Taraxacum coreanum protects against glutamate-induced neurotoxicity through heme oxygenase-1 expression in mouse hippocampal HT22 cells.

PubMed

Yoon, Chi-Su; Ko, Wonmin; Lee, Dong-Sung; Kim, Dong-Cheol; Kim, Jongsu; Choi, Moonbum; Beom, Jin Seon; An, Ren-Bo; Oh, Hyuncheol; Kim, Youn-Chul

2017-04-01

Taraxacum coreanum Nakai is a dandelion that is native to Korea, and is widely used as an edible and medicinal herb. The present study revealed the neuroprotective effect of this plant against glutamate-induced oxidative stress in HT22 murine hippocampal neuronal cells. Ethanolic extracts from the aerial (TCAE) and the root parts (TCRE) of T. coreanum were prepared. Both extracts were demonstrated, by high performance liquid chromatography, to contain caffeic acid and ferulic acid as representative constituents. TCAE and TCRE significantly increased cell viability against glutamate-induced oxidative stress in mouse hippocampal HT22 cells. Western blot analysis revealed that treatment of HT22 cells with the extracts induced increased expression of the enzyme heme oxygenase-1 (HO-1), compared with untreated cells, in a concentration-dependent manner. Increased HO-1 enzymatic activity, compared with untreated cells, was also demonstrated following treatment with TCAE and TCRE. In addition, western blot analysis of the nuclear fractions of both TCAE and TCRE-treated HT22 cells revealed increased levels of nuclear factor erythroid 2 like 2 (Nrf2) compared with untreated cells, and decreased Nrf2 levels in the cytoplasmic fraction compared with untreated cells. The present study suggested that the neuroprotective effect of T. coreanum is associated with induction of HO-1 expression and Nrf2 translocation to the nucleus. Therefore, T. coreanum exhibits a promising function in prevention of neurodegeneration. Further studies will be required for the isolation and the full characterization of its active substances.

Modulatory Role of Postsynaptic 5-Hydroxytryptamine Type 1A Receptors in (±)-8-Hydroxy-N,N-dipropyl-2-aminotetralin-Induced Hyperphagia in Mice.

PubMed

Brosda, Jan; Müller, Nadine; Bert, Bettina; Fink, Heidrun

2015-07-15

Brain serotonin (5-HT) is involved in the control of food intake. The ingestive effects of 5-HT are mediated by various receptor subtypes, among others the 5-HT1A receptor. While the involvement of presynaptic 5-HT1A receptors is regarded as certain, the role of postsynaptic 5-HT1A receptors is rather vague. Here, we studied the role of the 5-HT1A receptor on feeding in non-food-deprived and food-deprived (young adult and adult, both sexes) wild-type NMRI mice as well as transgenic NMRI mice, which are characterized by a distinct overexpression of postsynaptic 5-HT1A receptors. The known hyperphagic effect of the 5-HT1A receptor full agonist 8-OH-DPAT ((±)-8-hydroxy-N,N-dipropyl-2-aminotetralin) in non-food-deprived animals was demonstrated in male NMRI wild-type mice and could be antagonized by the selective 5-HT1A receptor antagonist WAY100635. In transgenic mice, this hyperphagic response was induced at lower doses, with an earlier onset and even in females. However, in adult male transgenic mice, the hyperphagic effect did not occur. In food-deprived NMRI wild-type as well as transgenic mice, 8-OH-DPAT first induced a hypophagic and subsequently a hyperphagic effect. Again, in transgenic animals most responses occurred at lower doses and with an earlier onset. The results indicate that postsynaptic 5-HT1A receptors exert a modulatory function in food intake in free-feeding and fasted mice, which for the first time shows an involvement of postsynaptic 5-HT1A receptors in feeding behavior. Understanding the function of pre- and postsynaptic 5-HT1A receptors may help to achieve new insights into the regulation of food intake and foster prospective treatment strategies for eating disorders.

Serotonin hyperinnervation and upregulated 5-HT2A receptor expression and motor-stimulating function in nigrostriatal dopamine-deficient Pitx3 mutant mice.

PubMed

Li, Li; Qiu, Guozhen; Ding, Shengyuan; Zhou, Fu-Ming

2013-01-23

The striatum receives serotonin (5-hydroxytryptamine, 5-HT) innervation and expresses 5-HT2A receptors (5-HT2ARs) and other 5-HT receptors, raising the possibility that the striatal 5-HT system may undergo adaptive changes after chronic severe dopamine (DA) loss and contribute to the function and dysfunction of the striatum. Here we show that in transcription factor Pitx3 gene mutant mice with a selective, severe DA loss in the dorsal striatum mimicking the DA denervation in late Parkinson's disease (PD), both the 5-HT innervation and the 5-HT2AR mRNA expression were increased in the dorsal striatum. Functionally, while having no detectable motor effect in wild type mice, the 5-HT2R agonist 2,5-dimethoxy-4-iodoamphetamine increased both the baseline and l-dopa-induced normal ambulatory and dyskinetic movements in Pitx3 mutant mice, whereas the selective 5-HT2AR blocker volinanserin had the opposite effects. These results demonstrate that Pitx3 mutant mice are a convenient and valid mouse model to study the compensatory 5-HT upregulation following the loss of the nigrostriatal DA projection and that the upregulated 5-HT2AR function in the DA deficient dorsal striatum may enhance both normal and dyskinetic movements. Copyright © 2012 Elsevier B.V. All rights reserved.

Effect of glial cell line-derived neurotrophic factor on behavior and key members of the brain serotonin system in mouse strains genetically predisposed to behavioral disorders.

PubMed

Naumenko, Vladimir S; Bazovkina, Daria V; Semenova, Alina A; Tsybko, Anton S; Il'chibaeva, Tatyana V; Kondaurova, Elena M; Popova, Nina K

2013-12-01

The effect of glial cell line-derived neurotrophic factor (GDNF) on behavior and on the serotonin (5-HT) system of a mouse strain predisposed to depressive-like behavior, ASC/Icg (Antidepressant Sensitive Cataleptics), in comparison with the parental "nondepressive" CBA/Lac mice was studied. Within 7 days after acute administration, GDNF (800 ng, i.c.v.) decreased cataleptic immobility but increased depressive-like behavioral traits in both investigated mouse strains and produced anxiolytic effects in ASC mice. The expression of the gene encoding the key enzyme for 5-HT biosynthesis in the brain, tryptophan hydroxylase-2 (Tph-2), and 5-HT1A receptor gene in the midbrain as well as 5-HT2A receptor gene in the frontal cortex were increased in GDNF-treated ASC mice. At the same time, GDNF decreased 5-HT1A and 5-HT2A receptor gene expression in the hippocampus of ASC mice. GDNF failed to change Tph2, 5-HT1A , or 5-HT2A receptor mRNA levels in CBA mice as well as 5-HT transporter gene expression and 5-HT1A and 5-HT2A receptor functional activity in both investigated mouse strains. The results show 1) a GDNF-induced increase in the expression of key genes of the brain 5-HT system, Tph2, 5-HT1A , and 5-HT2A receptors, and 2) significant genotype-dependent differences in the 5-HT system response to GDNF treatment. The data suggest that genetically defined cross-talk between neurotrophic factors and the brain 5-HT system underlies the variability in behavioral response to GDNF. Copyright © 2013 Wiley Periodicals, Inc.

Activation of serotonin 2C receptors in dopamine neurons inhibits binge-like eating in mice

PubMed Central

Xu, Pingwen; He, Yanlin; Cao, Xuehong; Valencia-Torres, Lourdes; Yan, Xiaofeng; Saito, Kenji; Wang, Chunmei; Yang, Yongjie; Hinton, Antentor; Zhu, Liangru; Shu, Gang; Myers, Martin G.; Wu, Qi; Tong, Qingchun; Heisler, Lora K.; Xu, Yong

2016-01-01

Background Neural networks that regulate binge eating remain to be identified, and effective treatments for binge eating are limited. Methods We combined neuroanatomical, pharmacological, electrophysiological, Cre-lox, and chemogenetic approaches to investigate the functions of 5-HT 2C receptor (5-HT2CR) expressed by dopamine (DA) neurons in the regulation of binge-like eating behavior in mice. Results We showed that 5-HT stimulates DA neural activity through a 5-HT2CR-mediated mechansim, and activation of this midbrain 5-HT-DA neural circuit effectively inhibits binge-like eating behavior in mice. Notably, 5-HT medications, including fluoxetine, d-Fenfluramine, and lorcaserin (a selective 5-HT2CR agonist), act upon 5-HT2CRs expressed by DA neurons to inhibit binge-like eating in mice. Conclusions We identified the 5-HT2CR population in DA neurons as one potential target for anti-binge therapies, and provided pre-clinical evidence that 5-HT2CR agonists could be used to treat binge eating. PMID:27516377

Sleep apneas are increased in mice lacking monoamine oxidase A.

PubMed

Real, Caroline; Popa, Daniela; Seif, Isabelle; Callebert, Jacques; Launay, Jean-Marie; Adrien, Joëlle; Escourrou, Pierre

2007-10-01

Alterations in the serotonin (5-HT) system have been suggested as a mechanism of sleep apnea in humans and rodents. The objective is to evaluate the contribution of 5-HT to this disorder. We studied sleep and breathing (whole-body plethysmography) in mutant mice that lack monoamine oxidase A (MAOA) and have increased concentrations of monoamines, including 5-HT. Compared to wild-type mice, the mutants showed similar amounts of slow wave sleep (SWS) and rapid eye movement sleep (REMS), but exhibited a 3-fold increase in SWS and REMS apnea indices. Acute administration of the MAOA inhibitor clorgyline decreased REMS amounts and increased the apnea index in wild-type but not mutant mice. Parachlorophenylalanine, a 5-HT synthesis inhibitor, reduced whole brain concentrations of 5-HT in both strains, and induced a decrease in apnea index in mutant but not wild-type mice. Our results show that MAOA deficiency is associated with increased sleep apnea in mice and suggest that an acute or chronic excess of 5-HT contributes to this phenotype.

Sleep Homeostatic and Waking Behavioral Phenotypes in Egr3-Deficient Mice Associated with Serotonin Receptor 5-HT2 Deficits

PubMed Central

Grønli, Janne; Clegern, William C.; Schmidt, Michelle A.; Nemri, Rahmi S.; Rempe, Michael J.; Gallitano, Amelia L.; Wisor, Jonathan P.

2016-01-01

Study Objective: The expression of the immediate early gene early growth response 3 (Egr3) is a functional marker of brain activity including responses to novelty, sustained wakefulness, and sleep. We examined the role of this gene in regulating wakefulness and sleep. Methods: Electroencephalogram/electromyogram (EEG/EMG) were recorded in Egr3-/- and wild-type (WT) mice during 24 h baseline, 6 h sleep disruption and 6 h recovery. Serotonergic signaling was assessed with 6 h EEG/EMG recordings after injections of nonselective 5-HT2 antagonist (clozapine), selective 5-HT2 antagonists (5-HT2A; MDL100907 and 5-HT2BC; SB206553) and a cocktail of both selective antagonists, administered in a randomized order to each animal. Results: Egr3-/- mice did not exhibit abnormalities in the timing of wakefulness and slow wave sleep (SWS); however, EEG dynamics in SWS (suppressed 1–3 Hz power) and in quiet wakefulness (elevated 3–8 Hz and 15–35 Hz power) differed in comparison to WT-mice. Egr3-/- mice showed an exaggerated response to sleep disruption as measured by active wakefulness, but with a blunted increase in homeostatic sleep drive (elevated 1–4 Hz power) relative to WT-mice. Egr3-/-mice exhibit greatly reduced sedative effects of clozapine at the electroencephalographic level. In addition, clozapine induced a previously undescribed dissociated state (low amplitude, low frequency EEG and a stable, low muscle tone) lasting up to 2 h in WT-mice. Egr3-/- mice did not exhibit this phenomenon. Selective 5-HT2A antagonist, alone or in combination with selective 5-HT2BC antagonist, caused EEG slowing coincident with behavioral quiescence in WT-mice but not in Egr3-/- mice. Conclusion: Egr3 has an essential role in regulating cortical arousal, wakefulness, and sleep, presumably by its regulation of 5-HT2 receptors. Citation: Grønli J, Clegern WC, Schmidt MA, Nemri RS, Rempe MJ, Gallitano AL, Wisor JP. Sleep homeostatic and waking behavioral phenotypes in Egr3-deficient mice associated with serotonin receptor 5-HT2 deficits. SLEEP 2016;39(12):2189–2199. PMID:28057087

Preservation of Essential Odor-Guided Behaviors and Odor-Based Reversal Learning after Targeting Adult Brain Serotonin Synthesis.

PubMed

Carlson, Kaitlin S; Whitney, Meredith S; Gadziola, Marie A; Deneris, Evan S; Wesson, Daniel W

2016-01-01

The neurotransmitter serotonin (5-HT) is considered a powerful modulator of sensory system organization and function in a wide range of animals. The olfactory system is innervated by midbrain 5-HT neurons into both its primary and secondary odor-processing stages. Facilitated by this circuitry, 5-HT and its receptors modulate olfactory system function, including odor information input to the olfactory bulb. It is unknown, however, whether the olfactory system requires 5-HT for even its most basic behavioral functions. To address this question, we established a conditional genetic approach to specifically target adult brain tryptophan hydroxylase 2 ( Tph2 ), encoding the rate-limiting enzyme in brain 5-HT synthesis, and nearly eliminate 5-HT from the mouse forebrain. Using this novel model, we investigated the behavior of 5-HT-depleted mice during performance in an olfactory go/no-go task. Surprisingly, the near elimination of 5-HT from the forebrain, including the olfactory bulbs, had no detectable effect on the ability of mice to perform the odor-based task. Tph2 -targeted mice not only were able to learn the task, but also had levels of odor acuity similar to those of control mice when performing coarse odor discrimination. Both groups of mice spent similar amounts of time sampling odors during decision-making. Furthermore, odor reversal learning was identical between 5-HT-depleted and control mice. These results suggest that 5-HT neurotransmission is not necessary for the most essential aspects of olfaction, including odor learning, discrimination, and certain forms of cognitive flexibility.

Sleep Homeostatic and Waking Behavioral Phenotypes in Egr3-Deficient Mice Associated with Serotonin Receptor 5-HT2 Deficits.

PubMed

Grønli, Janne; Clegern, William C; Schmidt, Michelle A; Nemri, Rahmi S; Rempe, Michael J; Gallitano, Amelia L; Wisor, Jonathan P

2016-12-01

The expression of the immediate early gene early growth response 3 ( Egr3 ) is a functional marker of brain activity including responses to novelty, sustained wakefulness, and sleep. We examined the role of this gene in regulating wakefulness and sleep. Electroencephalogram/electromyogram (EEG/EMG) were recorded in Egr3 -/- and wild-type (WT) mice during 24 h baseline, 6 h sleep disruption and 6 h recovery. Serotonergic signaling was assessed with 6 h EEG/EMG recordings after injections of nonselective 5-HT2 antagonist (clozapine), selective 5-HT2 antagonists (5-HT2A; MDL100907 and 5-HT2BC; SB206553) and a cocktail of both selective antagonists, administered in a randomized order to each animal. Egr3 -/- mice did not exhibit abnormalities in the timing of wakefulness and slow wave sleep (SWS); however, EEG dynamics in SWS (suppressed 1-3 Hz power) and in quiet wakefulness (elevated 3-8 Hz and 15-35 Hz power) differed in comparison to WT-mice. Egr3 -/- mice showed an exaggerated response to sleep disruption as measured by active wakefulness, but with a blunted increase in homeostatic sleep drive (elevated 1-4 Hz power) relative to WT-mice. Egr3 -/-mice exhibit greatly reduced sedative effects of clozapine at the electroencephalographic level. In addition, clozapine induced a previously undescribed dissociated state (low amplitude, low frequency EEG and a stable, low muscle tone) lasting up to 2 h in WT-mice. Egr3 -/- mice did not exhibit this phenomenon. Selective 5-HT2A antagonist, alone or in combination with selective 5-HT2BC antagonist, caused EEG slowing coincident with behavioral quiescence in WT-mice but not in Egr3 -/- mice. Egr3 has an essential role in regulating cortical arousal, wakefulness, and sleep, presumably by its regulation of 5-HT2 receptors. © 2016 Associated Professional Sleep Societies, LLC.

Gq/5-HT2c receptor signals activate a local GABAergic inhibitory feedback circuit to modulate serotonergic firing and anxiety in mice.

PubMed

Spoida, Katharina; Masseck, Olivia A; Deneris, Evan S; Herlitze, Stefan

2014-04-29

Serotonin 2c receptors (5-HT2c-Rs) are drug targets for certain mental disorders, including schizophrenia, depression, and anxiety. 5-HT2c-Rs are expressed throughout the brain, making it difficult to link behavioral changes to circuit specific receptor expression. Various 5-HT-Rs, including 5-HT2c-Rs, are found in the dorsal raphe nucleus (DRN); however, the function of 5-HT2c-Rs and their influence on the serotonergic signals mediating mood disorders remain unclear. To investigate the role of 5-HT2c-Rs in the DRN in mice, we developed a melanopsin-based optogenetic probe for activation of Gq signals in cellular domains, where 5-HT2c-Rs are localized. Our results demonstrate that precise temporal control of Gq signals in 5-HT2c-R domains in GABAergic neurons upstream of 5-HT neurons provides negative feedback regulation of serotonergic firing to modulate anxiety-like behavior in mice.

Gq/5-HT2c receptor signals activate a local GABAergic inhibitory feedback circuit to modulate serotonergic firing and anxiety in mice

PubMed Central

Spoida, Katharina; Masseck, Olivia A.; Deneris, Evan S.; Herlitze, Stefan

2014-01-01

Serotonin 2c receptors (5-HT2c-Rs) are drug targets for certain mental disorders, including schizophrenia, depression, and anxiety. 5-HT2c-Rs are expressed throughout the brain, making it difficult to link behavioral changes to circuit specific receptor expression. Various 5-HT-Rs, including 5-HT2c-Rs, are found in the dorsal raphe nucleus (DRN); however, the function of 5-HT2c-Rs and their influence on the serotonergic signals mediating mood disorders remain unclear. To investigate the role of 5-HT2c-Rs in the DRN in mice, we developed a melanopsin-based optogenetic probe for activation of Gq signals in cellular domains, where 5-HT2c-Rs are localized. Our results demonstrate that precise temporal control of Gq signals in 5-HT2c-R domains in GABAergic neurons upstream of 5-HT neurons provides negative feedback regulation of serotonergic firing to modulate anxiety-like behavior in mice. PMID:24733892

The Hypothalamic-Pituitary-Adrenal Axis and Serotonin Metabolism in Individual Brain Nuclei of Mice with Genetic Disruption of the NK1 Receptor Exposed to Acute Stress.

PubMed

Culman, Juraj; Mühlenhoff, Stephan; Blume, Annegret; Hedderich, Jürgen; Lützen, Ulf; Hunt, Stephen P; Rupniak, Nadia M J; Zhao, Yi

2018-06-15

Mice lacking the substance P (SP) neurokinin-1 (NK1) receptor (NK1R-/-mice) were used to investigate whether SP affects serotonin (5-HT) function in the brain and to assess the effects of acute immobilisation stress on the hypothalamic-pituitary-adrenocortical (HPA) axis and 5-HT turnover in individual brain nuclei. Basal HPA activity and the expression of hypothalamic corticotropin-releasing hormone (CRH) in wild-type (WT)- and NK1R-/- mice were identical. Stress-induced increases in plasma ACTH concentration were considerably higher in NK1R-/- mice than in WT mice while corticosterone concentrations were equally elevated in both mouse lines. Acute stress did not alter the expression of CRH. In the dorsal raphe nucleus (DRN), basal 5-HT turnover was increased in NK1R-/- mice and a 15 min stress further magnified 5-HT utilisation in this region. In the frontoparietal cortex, medial prefrontal cortex, central nucleus of amygdala, and the hippocampal CA1 region, stress increased 5-HT and/or 5-hydroxyindoleacetic acid (5-HIAA) concentrations to a similar extent in WT and NK1R-/- mice. 5-HT turnover in the hypothalamic paraventricular nucleus was not affected by stress, but stress induced similar increases in 5-HT and 5-HIAA in the ventromedial and dorsomedial hypothalamic nuclei in WT and NK1R-/- mice. Our findings indicate that NK1 receptor activation suppresses ACTH release during acute stress but does not exert sustained inhibition of the HPA axis. Genetic deletion of the NK1 receptor accelerates 5-HT turnover in DRN under basal and stress conditions. No differences between the responses of serotonergic system to acute stress in WT and NK1R-/- mice occur in forebrain nuclei linked to the regulation of anxiety and neuroendocrine stress responses.

Medullary 5-HT neurons: Switch from tonic respiratory drive to chemoreception during postnatal development

PubMed Central

Cerpa, Veronica J.; Wu, Yuanming; Bravo, Eduardo; Teran, Frida A.; Flynn, Rachel S.; Richerson, George B.

2016-01-01

Serotonin (5-HT) neurons contribute to respiratory chemoreception in adult mice, but it is unclear whether they play a similar role in neonatal mice. We studied breathing during development in Lmx1bf/f/p mice, which lack 5-HT neurons. From postnatal days 1–7 (P1–P7), ventilation of Lmx1bf/f/p mice breathing room air was 50% of WT mice (p < 0.001). By P12, baseline ventilation increased to a level equal to WT mice. In contrast, the hypercapnic ventilatory response (HCVR) of neonatal Lmx1bf/f/p and WT mice were equal to each other, but were both much less than adult WT mice. By P21 the HCVR of WT mice increased to near adult levels, but the HCVR of Lmx1bf/f/p mice had not changed, and was 42% less than WT mice. Primary cell cultures were prepared from the ventromedial medulla of neonatal mice, and patch-clamp recordings were made from neurons identified as serotonergic by expression of a reporter gene. In parallel with developmental changes of the HCVR in vivo, 5-HT neurons had little chemosensitivity to acidosis until 12 days in vitro (DIV), after which their response increased to reach a plateau around 25 DIV. Neonatal Lmx1bf/f/p mice displayed high mortality and decreased growth rate, and this worsened in hypoxia. Mortality was decreased in hyperoxia. These results indicate that maturation of 5-HT neurons contributes to development of respiratory CO2/pH chemoreception during the first few weeks of life in mice in vivo. A defect in the 5-HT system in early postnatal life decreases survival due in part to hypoxia. PMID:27619736

Role of the 5-HT2A receptor in the locomotor hyperactivity produced by phenylalkylamine hallucinogens in mice

PubMed Central

Halberstadt, Adam L.; Powell, Susan B.; Geyer, Mark A.

2014-01-01

The 5-HT2A receptor mediates the effects of serotonergic hallucinogens and may play a role in the pathophysiology of certain psychiatric disorders, including schizophrenia. Given these findings, there is a need for animal models to assess the behavioral effects of 5-HT2A receptor activation. Our previous studies demonstrated that the phenylalkylamine hallucinogen and 5-HT2A/2C agonist 2,5-dimethoxy-4-iodoamphetamine (DOI) produces dose-dependent effects on locomotor activity in C57BL/6J mice, increasing activity at low to moderate doses and reducing activity at high doses. DOI did not increase locomotor activity in 5-HT2A knockout mice, indicating the effect is a consequence of 5-HT2A receptor activation. Here, we tested a series of phenylalkylamine hallucinogens in C57BL/6J mice using the Behavioral Pattern Monitor (BPM) to determine whether these compounds increase locomotor activity by activating the 5-HT2A receptor. Low doses of mescaline, 2,5-dimethoxy-4-ethylamphetamine (DOET), 2,5-dimethoxy-4-propylamphetamine (DOPR), 2,4,5-trimethoxyamphetamine (TMA-2), and the conformationally restricted phenethylamine (4-bromo-3,6-dimethoxybenzocyclobuten-1-yl)methylamine (TCB-2) increased locomotor activity. By contrast, the non-hallucinogenic phenylalkylamine 2,5-dimethoxy-4-tert-butylamphetamine (DOTB) did not alter locomotor activity at any dose tested (0.1-10 mg/kg i.p.). The selective 5-HT2A antagonist M100907 blocked the locomotor hyperactivity induced by mescaline and TCB-2. Similarly, mescaline and TCB-2 did not increase locomotor activity in 5-HT2A knockout mice. These results confirm that phenylalkylamine hallucinogens increase locomotor activity in mice and demonstrate that this effect is mediated by 5-HT2A receptor activation. Thus, locomotor hyperactivity in mice can be used to assess phenylalkylamines for 5-HT2A agonist activity and hallucinogen-like behavioral effects. These studies provide additional support for the link between 5-HT2A activation and hallucinogenesis. PMID:23376711

5-HT2C Receptor Desensitization Moderates Anxiety in 5-HTT Deficient Mice: From Behavioral to Cellular Evidence

PubMed Central

Martin, Cédric BP; Martin, Vincent S.; Trigo, José M.; Chevarin, Caroline; Maldonado, Rafael; Fink, Latham H.; Cunningham, Kathryn A.; Hamon, Michel; Lanfumey, Laurence

2015-01-01

Background: Desensitization and blockade of 5-HT2C receptors (5-HT2CR) have long been thought to be central in the therapeutic action of antidepressant drugs. However, besides behavioral pharmacology studies, there is little in vivo data documenting antidepressant-induced 5-HT2CR desensitization in specific brain areas. Methods: Mice lacking the 5-HT reuptake carrier (5-HTT-/-) were used to model the consequences of chronic 5-HT reuptake inhibition with antidepressant drugs. The effect of this mutation on 5-HT2CR was evaluated at the behavioral (social interaction, novelty-suppressed feeding, and 5-HT2CR–induced hypolocomotion tests), the neurochemical, and the cellular (RT-qPCR, mRNA editing, and c-fos–induced expression) levels. Results: Although 5-HTT-/- mice had an anxiogenic profile in the novelty-suppressed feeding test, they displayed less 5-HT2CR–mediated anxiety in response to the agonist m-chlorophenylpiperazine in the social interaction test. In addition, 5-HT2CR–mediated inhibition of a stress-induced increase in 5-HT turnover, measured in various brain areas, was markedly reduced in 5-HTT-/- mutants. These indices of tolerance to 5-HT2CR stimulation were associated neither with altered levels of 5-HT2CR protein and mRNA nor with changes in pre-mRNA editing in the frontal cortex. However, basal c-fos mRNA production in cells expressing 5-HT2CR was higher in 5-HTT-/- mutants, suggesting an altered basal activity of these cells following sustained 5-HT reuptake carrier inactivation. Furthermore, the increased c-fos mRNA expression in 5-HT2CR–like immune-positive cortical cells observed in wild-type mice treated acutely with the 5-HT2CR agonist RO-60,0175 was absent in 5-HTT-/- mutants. Conclusions: Such blunted responsiveness of the 5-HT2CR system, observed at the cell signaling level, probably contributes to the moderation of the anxiety phenotype in 5-HTT-/- mice. PMID:25522398

Blockade of the high-affinity noradrenaline transporter (NET) by the selective 5-HT reuptake inhibitor escitalopram: an in vivo microdialysis study in mice

PubMed Central

Nguyen, Hai T; Guiard, Bruno P; Bacq, Alexandre; David, Denis J; David, Indira; Quesseveur, Gaël; Gautron, Sophie; Sanchez, Connie; Gardier, Alain M

2013-01-01

BACKGROUND AND PURPOSE Escitalopram, the S(+)-enantiomer of citalopram is the most selective 5-HT reuptake inhibitor approved. Although all 5-HT selective reuptake inhibitors (SSRIs) increase extracellular levels of 5-HT ([5-HT]ext). some also enhance, to a lesser extent, extracellular levels of noradrenaline ([NA]ext). However, the mechanisms by which SSRIs activate noradrenergic transmission in the brain remain to be determined. EXPERIMENTAL APPROACH This study examined the effects of escitalopram, on both [5-HT]ext and [NA]ext in the frontal cortex (FCx) of freely moving wild-type (WT) and mutant mice lacking the 5-HT transporter (SERT−/−) by using intracerebral microdialysis. We explored the possibilities that escitalopram enhances [NA]ext, either by a direct mechanism involving the inhibition of the low- or high-affinity noradrenaline transporters, or by an indirect mechanism promoted by [5-HT]ext elevation. The forced swim test (FST) was used to investigate whether enhancing cortical [5-HT]ext and/or [NA]ext affected the antidepressant-like activity of escitalopram. KEY RESULTS In WT mice, a single systemic administration of escitalopram produced a significant increase in cortical [5-HT]ext and [NA]ext. As expected, escitalopram failed to increase cortical [5-HT]ext in SERT−/− mice, whereas its neurochemical effects on [NA]ext persisted in these mutants. In WT mice subjected to the FST, escitalopram increased swimming parameters without affecting climbing behaviour. Finally, escitalopram, at relevant concentrations, failed to inhibit cortical noradrenaline and 5-HT uptake mediated by low-affinity monoamine transporters. CONCLUSIONS AND IMPLICATIONS These experiments suggest that escitalopram enhances, although moderately, cortical [NA]extin vivo by a direct mechanism involving the inhibition of the high-affinity noradrenaline transporter (NET). PMID:22233336

Molecular Regulation of Sexual Preference Revealed by Genetic Studies of 5-HT in the Brain of Male Mice

PubMed Central

Liu, Yan; Jiang, Yun’ai; Si, Yunxia; Kim, Ji-Young; Chen, Zhou-Feng; Rao, Yi

2014-01-01

To whom should a male directs his mating? While it is a critical social interaction, little is known about molecular and cellular mechanisms controlling mammalian sexual preference. Here we report that the neurotransmitter 5-HT is required for male sexual preference. Male mice lacking central serotonergic neurons lost sexual preference but were not generally defective in olfaction. A role for 5-hydroxytryptamine (5-HT) was demonstrated by the phenotype of mice unable to synthesize 5-HT in the brain when lacking tryptophan hydroxylase 2 (Tph2). 5-hydroxytryptophan (5-HTP) injection rescued the phenotype of adult Tph2 knockout mice within 35 minutes. These results indicate that 5-HT and serotonergic neurons in the adult brain regulate mammalian sexual preference. PMID:21441904

Increased ethanol preference and serotonin 1A receptor-dependent attenuation of ethanol-induced hypothermia in PACAP-deficient mice.

PubMed

Tanaka, Kazuhiro; Kunishige-Yamamoto, Akiko; Hashimoto, Hitoshi; Shintani, Norihito; Hayata, Atsuko; Baba, Akemichi

2010-01-01

Pituitary adenylate cyclase-activating polypeptide (PACAP)-deficient mice display remarkable behavioral changes including increased novelty-seeking behavior and reduced hypothermia induced by either serotonin (5-HT)(1A) receptor agonists or ethanol. Because 5-HT(1A) receptors have been implicated in the development of alcohol dependence, we have examined ethanol preference in PACAP-deficient mice using a two-bottle choice and a conditioned place preference test, as well as additive effects of ethanol and 5-HT(1A) receptor agents on hypothermia. PACAP-deficient mice showed an increased preference towards ethanol compared with wild-type mice. However, they showed no preference for the ethanol compartment after conditioning and neither preference nor aversion to sucrose or quinine. The 5-HT(1A) receptor agonist 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) restored the attenuated hypothermic response to ethanol in the mutants to similar levels in wild-type mice, with no effect in wild-types. In contrast, the 5-HT(1A) receptor antagonist WAY-100635 attenuated the ethanol-induced hypothermia in wild-type mice, with no effect in the mutants. These results demonstrate increased ethanol preference in PACAP-deficient mice that may be mediated by 5-HT(1A) receptor-dependent attenuation of ethanol-induced central inhibition. Copyright 2009 Elsevier Inc. All rights reserved.

Serotoninergic neuronal systems and ethanol sensitivity in long-sleep (LS) and short-sleep (SS) mice

DOE Office of Scientific and Technical Information (OSTI.GOV)

French, T.A.; Weiner, N.

LS and SS mice selectively bred for differences in CNS sensitivity to ethanol (EtOH) exhibit markedly different sleep times (LS = 120 min; SS = 13 min) and differ considerably in hypothermic response following EtOH< 4 g/kg i.p. Basal levels of serotonin (5HT), 5-hydroxyindole acetic acid and 5HT turnover (defined as 5-hydroxy-tryptophan accumulation after inhibition of aromatic L-amino acid decarboxylase) in 6 brain regions (hypthalamus (HYP), dorsal raphe (DR), pontine-medullary raphe (PMR), striatum (STR), hippocampus (HIP) and cortex (CTX)) differ minimally between the two lines. 5 HT turnover in STR, HIP, CTX and PMR of either LS or SS micemore » or in HYP or DR of SS mice was not altered at either 20 or 120 min after EtOH, 4 g/kg. However, in LS mice, 5HT turnover was decreased 23% in HYP at 20 min and 30-34% in HYP and DR at 120 min. LS mice become 1.2 and 2.2/sup 0/ more hypothermic than SS mice at 20 and 120 min after EtOH, 4 g/kg. When approximately equi-effective hypothermic doses of EtOH were administered to LS (3.5 g/kg) and SS (5.0 g/kg) mice, differences in 5HT turnover were still apparent. Pentobarbital administration (65 mg/kg) both decreased brain 5HT turnover 30-60% and produced comparable degrees of hypothermia in LS and SS mice. These data suggest that the apparent increase in sensitivity to inhibition by EtOH of 5HT neurons of HYP and DR of LS mice may contribute to the greater degree of hypothermia induced in this line.« less

ENHANCED 5-HT1A RECEPTOR-DEPENDENT FEEDBACK CONTROL OVER DORSAL RAPHE SEROTONIN NEURONS IN THE SERT KNOCKOUT MOUSE

PubMed Central

Soiza-Reilly, Mariano; Goodfellow, Nathalie M.; Lambe, Evelyn K.; Commons, Kathryn G.

2014-01-01

5-HT1A receptors are widely expressed in the brain and play a critical role in feedback inhibition of serotonin (5-HT) neurons through multiple mechanisms. Yet, it remains poorly understood how these feedback mechanisms, particularly those involving long-range projections, adapt in mood disorders. Here, we examined several aspects of 5-HT1A receptor function in the 5-HT transporter knockout mouse (SERT-KO), a model of vulnerability to stress and mood disorders. We found that in comparison to wild-type (WT) mice, SERT-KO mice had more passive coping in response to acute swim stress and this was accompanied by hypo-activation of medial prefrontal cortex (mPFC) Fos expression. Both of these effects were reversed by systemically blocking 5-HT1A receptors. Ex-vivo electrophysiological experiments showed that 5-HT exerted greater 5-HT1A-mediated inhibitory effects in the mPFC of SERT-KO mice compared to WT. Since 5-HT1A receptors in the mPFC provide a key feedback regulation of the dorsal raphe nucleus (DRN), we used a disinhibition strategy to examined endogenous feedback control of 5-HT neurons. Blocking 5-HT1A receptors disinhibited several fold more 5-HT neurons in the DRN of SERT-KO than in WT mice, revealing the presence of enhanced feedback inhibition of 5-HT neurons in the SERT-KO. Taken together our results indicate that increased stress sensitivity in the SERT-KO is associated with the enhanced capacity of 5-HT1A receptors to inhibit neurons in the mPFC as well as to exert feedback inhibition of DRN 5-HT neurons. PMID:25261781

Neurochemical, behavioral and physiological effects of pharmacologically enhanced serotonin levels in serotonin transporter (SERT)-deficient mice

PubMed Central

Fox, Meredith A.; Jensen, Catherine L.; French, Helen T.; Stein, Alison R.; Huang, Su-Jan; Tolliver, Teresa J.; Murphy, Dennis L.

2008-01-01

Rationale Serotonin transporter (SERT) knockout (−/−) mice have an altered phenotype in adulthood, including high baseline anxiety and depressive-like behaviors, associated with increased baseline extracellular serotonin levels throughout life. Objectives To examine the effects of increases in serotonin following administration of the serotonin precursor 5-hydroxy-L-tryptophan (5-HTP) in SERT wildtype (+/+), heterozygous (+/−) and −/− mice. Results 5-HTP increased serotonin in all five brain areas examined, with ~2–5-fold increases in SERT +/+ and +/− mice, and greater 4.5–11.7-fold increases in SERT −/− mice. Behaviorally, 5-HTP induced exaggerated serotonin syndrome behaviors in SERT −/− mice, with similar effects in male and female mice. Studies suggest promiscuous serotonin uptake by the dopamine transporter (DAT) in SERT −/− mice, and here, the DAT blocker GBR 12909 enhanced 5-HTP-induced behaviors in SERT −/− mice. Physiologically, 5-HTP induced exaggerated temperature effects in SERT-deficient mice. The 5-HT1A antagonist WAY 100635 decreased 5-HTP-induced hypothermia in SERT +/+ and +/− mice, with no effect in SERT −/− mice, whereas the 5-HT7 antagonist SB 269970 decreased this exaggerated response in SERT −/− mice only. WAY 100635 and SB 269970 together completely blocked 5-HTP-induced hypothermia in SERT +/− and −/− mice. Conclusions These studies demonstrate that SERT −/− mice have exaggerated neurochemical, behavioral and physiological responses to further increases in serotonin, and provide the first evidence of intact 5-HT7 receptor function in SERT −/− mice, with interesting interactions between 5-HT1A and 5-HT7 receptors. As roles for 5-HT7 receptors in anxiety and depression were recently established, the current findings have implications for understanding the high anxiety and depressive-like phenotype of SERT-deficient mice. PMID:18712364

Hepatic tissue environment in NEMO-deficient mice critically regulates positive selection of donor cells after hepatocyte transplantation.

PubMed

Kaldenbach, Michaela; Cubero, Francisco Javier; Erschfeld, Stephanie; Liedtke, Christian; Trautwein, Christian; Streetz, Konrad

2014-01-01

Hepatocyte transplantation (HT) is a promising alternative treatment strategy for end-stage liver diseases compared with orthotopic liver transplantation. A limitation for this approach is the low engraftment of donor cells. The deletion of the I-kappa B kinase-regulatory subunit IKKγ/NEMO in hepatocytes prevents nuclear factor (NF)-kB activation and triggers spontaneous liver apoptosis, chronic hepatitis and the development of liver fibrosis and hepatocellular carcinoma. We hypothesized that NEMOΔhepa mice may therefore serve as an experimental model to study HT. Pre-conditioned NEMOΔhepa mice were transplanted with donor-hepatocytes from wildtype (WT) and mice deficient for the pro-apoptotic mediator Caspase-8 (Casp8Δhepa). Transplantation of isolated WT-hepatocytes into pre-conditioned NEMOΔhepa mice resulted in a 6-7 fold increase of donor cells 12 weeks after HT, while WT-recipients showed no liver repopulation. The use of apoptosis-resistant Casp8Δhepa-derived donor cells further enhanced the selection 3-fold after 12-weeks and up to 10-fold increase after 52 weeks compared with WT donors. While analysis of NEMOΔhepa mice revealed strong liver injury, HT-recipient NEMOΔhepa mice showed improved liver morphology and decrease in serum transaminases. Concomitant with these findings, the histological examination elicited an improved liver tissue architecture associated with significantly lower levels of apoptosis, decreased proliferation and a lesser amount of liver fibrogenesis. Altogether, our data clearly support the therapeutic benefit of the HT procedure into NEMOΔhepa mice. This study demonstrates the feasibility of the NEMOΔhepa mouse as an in vivo tool to study liver repopulation after HT. The improvement of the characteristic phenotype of chronic liver injury in NEMOΔhepa mice after HT suggests the therapeutic potential of HT in liver diseases with a chronic inflammatory phenotype and opens a new door for the applicability of this technique to combat liver disease in the human clinic.

Hepatic Tissue Environment in NEMO-Deficient Mice Critically Regulates Positive Selection of Donor Cells after Hepatocyte Transplantation

PubMed Central

Kaldenbach, Michaela; Cubero, Francisco Javier; Erschfeld, Stephanie; Liedtke, Christian; Trautwein, Christian; Streetz, Konrad

2014-01-01

Background Hepatocyte transplantation (HT) is a promising alternative treatment strategy for end-stage liver diseases compared with orthotopic liver transplantation. A limitation for this approach is the low engraftment of donor cells. The deletion of the I-kappa B kinase-regulatory subunit IKKγ/NEMO in hepatocytes prevents nuclear factor (NF)-kB activation and triggers spontaneous liver apoptosis, chronic hepatitis and the development of liver fibrosis and hepatocellular carcinoma. We hypothesized that NEMOΔhepa mice may therefore serve as an experimental model to study HT. Methods Pre-conditioned NEMOΔhepa mice were transplanted with donor-hepatocytes from wildtype (WT) and mice deficient for the pro-apoptotic mediator Caspase-8 (Casp8Δhepa). Results Transplantation of isolated WT-hepatocytes into pre-conditioned NEMOΔhepa mice resulted in a 6-7 fold increase of donor cells 12 weeks after HT, while WT-recipients showed no liver repopulation. The use of apoptosis-resistant Casp8Δhepa-derived donor cells further enhanced the selection 3-fold after 12-weeks and up to 10-fold increase after 52 weeks compared with WT donors. While analysis of NEMOΔhepa mice revealed strong liver injury, HT-recipient NEMOΔhepa mice showed improved liver morphology and decrease in serum transaminases. Concomitant with these findings, the histological examination elicited an improved liver tissue architecture associated with significantly lower levels of apoptosis, decreased proliferation and a lesser amount of liver fibrogenesis. Altogether, our data clearly support the therapeutic benefit of the HT procedure into NEMOΔhepa mice. Conclusion This study demonstrates the feasibility of the NEMOΔhepa mouse as an in vivo tool to study liver repopulation after HT. The improvement of the characteristic phenotype of chronic liver injury in NEMOΔhepa mice after HT suggests the therapeutic potential of HT in liver diseases with a chronic inflammatory phenotype and opens a new door for the applicability of this technique to combat liver disease in the human clinic. PMID:24979756

Effect of brain-derived neurotrophic factor on behavior and key members of the brain serotonin system in genetically predisposed to behavioral disorders mouse strains.

PubMed

Naumenko, V S; Kondaurova, E M; Bazovkina, D V; Tsybko, A S; Tikhonova, M A; Kulikov, A V; Popova, N K

2012-07-12

The effect of brain-derived neurotrophic factor (BDNF) on depressive-like behavior and serotonin (5-HT) system in the brain of antidepressant sensitive cataleptics (ASC)/Icg mouse strain, characterized by depressive-like behavior, in comparison with the parental nondepressive CBA/Lac mouse strain was examined. Significant decrease of catalepsy and tail suspension test (TST) immobility was shown 17days after acute central BDNF administration (300ng i.c.v.) in ASC mice. In CBA mouse strain, BDNF moderately decreased catalepsy without any effect on TST immobility time. Significant difference between ASC and CBA mice in the effect of BDNF on 5-HT system was revealed. It was shown that central administration of BDNF led to increase of 5-HT(1A) receptor gene expression but not 5-HT(1A) functional activity in ASC mice. Increased tryptophan hydroxylase-2 (Tph-2) and 5-HT(2A) receptor genes expression accompanied by 5-HT(2A) receptor sensitization was shown in BDNF-treated ASC but not in CBA mouse strain, suggesting BDNF-induced increase of the brain 5-HT system functional activity and activation of neurogenesis in "depressive" ASC mice. There were no changes found in the 5-HT transporter mRNA level in BDNF-treated ASC and CBA mice. In conclusion, central administration of BDNF produced prolonged ameliorative effect on depressive-like behavior accompanied by increase of the Tph-2, 5-HT(1A) and 5-HT(2A) genes expression and 5-HT(2A) receptor functional activity in animal model of hereditary behavior disorders. Copyright © 2012 IBRO. Published by Elsevier Ltd. All rights reserved.

Metabotropic glutamate mGlu2 receptor is necessary for the pharmacological and behavioral effects induced by hallucinogenic 5-HT2A receptor agonists.

PubMed

Moreno, José L; Holloway, Terrell; Albizu, Laura; Sealfon, Stuart C; González-Maeso, Javier

2011-04-15

Hallucinogenic drugs, including mescaline, psilocybin and lysergic acid diethylamide (LSD), act at serotonin 5-HT2A receptors (5-HT2ARs). Metabotropic glutamate receptor 2/3 (mGluR2/3) ligands show efficacy in modulating the responses induced by activation of 5-HT2ARs. The formation of a 5-HT2AR-mGluR2 complex suggests a functional interaction that affects the hallucinogen-regulated cellular signaling pathways. Here, we tested the cellular and behavioral effects of hallucinogenic 5-HT2AR agonists in mGluR2 knockout (mGluR2-KO) mice. Mice were intraperitoneally injected with the hallucinogens DOI (2 mg/kg) and LSD (0.24 mg/kg), or vehicle. Head-twitch behavioral response, expression of c-fos, which is induced by all 5-HT2AR agonists, and expression of egr-2, which is hallucinogen-specific, were determined in wild type and mGluR2-KO mice. [(3)H]Ketanserin binding displacement curves by DOI were performed in mouse frontal cortex membrane preparations. Head twitch behavior was abolished in mGluR2-KO mice. The high-affinity binding site of DOI was undetected in mGluR2-KO mice. The hallucinogen DOI induced c-fos in both wild type and mGluR2-KO mice. However, the induction of egr-2 by DOI was eliminated in mGlu2-KO mice. These findings suggest that the 5-HT2AR-mGluR2 complex is necessary for the neuropsychological responses induced by hallucinogens. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Neuronal Tryptophan Hydroxylase Expression in BALB/cJ and C57Bl/6J Mice

PubMed Central

Bach, Helene; Arango, Victoria; Huang, Yung-Yu; Leong, Sharlene; Mann, J. John; Underwood, Mark D.

2014-01-01

BALB/c is an inbred stress-sensitive mouse strain exhibiting low brain serotonin (5-HT) content and a 5-HT biosynthetic enzyme tryptophan hydroxylase (Tph2) variant reported to have lower catalytic activity compared to other inbred base strains. To evaluate other mechanisms that may explain low 5-HT, we compared BALB/cJ mice and a control inbred strain C57Bl/6J mice, for expression of Tph2 mRNA, TPH2 protein and regional levels of 5-HT and its metabolite 5-hydroxyindoleacetic acid (5-HIAA). Tph2 mRNA and TPH2 protein in brainstem dorsal raphe nuclei (DRN) was assayed by in situ hybridization and immunocytochemistry respectively. 5-HT and 5-HIAA were determined by high pressure liquid chromatography (HPLC). BALB/cJ mice had 20% less Tph2 mRNA and 28% fewer TPH2 immunolabeled neurons than C57Bl/6J mice (t = -2.59, p = 0.02). The largest difference in Tph2 transcript expression was in rostral DRN (t = 2.731, p = 0.008). 5-HT was 15% lower in the midbrain of BALB/cJ compared to C57Bl/6J mice (p < 0.05). The behavioral differences in BALB/cJ mice relative to the C57Bl/6J strain may be due in part, to fewer 5-HT neurons and lower Tph2 gene expression resulting in less 5-HT neurotransmission. Future studies quantifying expression per neuron are needed to determine whether less expression is explained by fewer neurons or also less expression per neuron, or both. PMID:21740442

Neuronal tryptophan hydroxylase expression in BALB/cJ and C57Bl/6J mice.

PubMed

Bach, Helene; Arango, Victoria; Huang, Yung-Yu; Leong, Sharlene; Mann, J John; Underwood, Mark D

2011-09-01

BALB/c is an inbred stress-sensitive mouse strain exhibiting low brain serotonin (5-HT) content and a 5-HT biosynthetic enzyme tryptophan hydroxylase (Tph2) variant reported to have lower catalytic activity compared with other inbred base strains. To evaluate other mechanisms that may explain low 5-HT, we compared BALB/cJ mice and a control inbred strain C57Bl/6J mice, for expression of Tph2 mRNA, TPH2 protein and regional levels of 5-HT and its metabolite 5-hydroxyindoleacetic acid. Tph2 mRNA and TPH2 protein in brainstem dorsal raphe nuclei was assayed by in situ hybridization and immunocytochemistry respectively. 5-HT and 5-hydroxyindoleacetic acid were determined by HPLC. BALB/cJ mice had 20% less Tph2 mRNA and 28% fewer TPH2 immunolabeled neurons than C57Bl/6J mice (t = -2.59, p = 0.02). The largest difference in Tph2 transcript expression was in rostral dorsal raphe nuclei (t = 2.731, p = 0.008). 5-HT was 15% lower in the midbrain and 18% lower in the cerebral cortex of BALB/cJ compared with C57Bl/6J mice (p < 0.05). The behavioral differences in BALB/cJ mice relative to the C57Bl/6J strain may be due in part, to fewer 5-HT neurons and lower Tph2 gene expression resulting in less 5-HT neurotransmission. Future studies quantifying expression per neuron are needed to determine whether less expression is explained by fewer neurons or also less expression per neuron, or both. © 2011 The Authors. Journal of Neurochemistry © 2011 International Society for Neurochemistry.

Metabotropic glutamate mGlu2 receptor is necessary for the pharmacological and behavioral effects induced by hallucinogenic 5-HT2A receptor agonists

PubMed Central

Moreno, José L.; Holloway, Terrell; Albizu, Laura; Sealfon, Stuart C.; González-Maeso, Javier

2011-01-01

Hallucinogenic drugs, including mescaline, psilocybin and lysergic acid diethylamide (LSD), act at serotonin 5-HT2A receptors (5-HT2ARs). Metabotropic glutamate receptor 2/3 (mGluR2/3) ligands show efficacy in modulating the responses induced by activation of 5-HT2ARs. The formation of a 5-HT2AR-mGluR2 complex suggests a functional interaction that affects the hallucinogen-regulated cellular signaling pathways. Here, we tested the cellular and behavioral effects of hallucinogenic 5-HT2AR agonists in mGluR2 knockout (mGluR2-KO) mice. Mice were intraperitoneally injected with the hallucinogens DOI (2 mg/kg) and LSD (0.24 mg/kg), or vehicle. Head-twitch behavioral response, expression of c-fos, which is induced by all 5-HT2AR agonists, and expression of egr-2, which is hallucinogen-specific, were determined in wild type and mGluR2-KO mice. [3H]Ketanserin binding displacement curves by DOI were performed in mouse frontal cortex membrane preparations. Head twitch behavior was abolished in mGluR2-KO mice. The high-affinity binding site of DOI was undetected in mGluR2-KO mice. The hallucinogen DOI induced c-fos in both wild type and mGluR2-KO mice. However, the induction of egr-2 by DOI was eliminated in mGlu2-KO mice. These findings suggest that the 5-HT2AR-mGluR2 complex is necessary for the neuropsychological responses induced by hallucinogens. PMID:21276828

Differential long-term effects of MDMA on the serotoninergic system and hippocampal cell proliferation in 5-HTT knock-out vs. wild-type mice.

PubMed

Renoir, Thibault; Païzanis, Eleni; El Yacoubi, Malika; Saurini, Françoise; Hanoun, Naïma; Melfort, Maxette; Lesch, Klaus Peter; Hamon, Michel; Lanfumey, Laurence

2008-12-01

Although numerous studies investigated the mechanisms underlying 3,4-methylenedioxymethamphetamine (MDMA)-induced neurotoxicity, little is known about its long-term functional consequences on 5-HT neurotransmission in mice. This led us to evaluate the delayed effects of MDMA exposure on the 5-HT system, using in-vitro and in-vivo approaches in both 5-HTT wild-type and knock-out mice. Acute MDMA in-vitro application on slices of the dorsal raphe nucleus (DRN) induced concentration-dependent 5-HT release and 5-HT cell firing inhibition. Four weeks after MDMA administration (20 mg/kg b.i.d for 4 d), a 2-fold increase in the potency of the 5-HT1A receptor agonist ipsapirone to inhibit the discharge of DRN 5-HT neurons and a larger hypothermic response to 8-OH-DPAT were observed in MDMA- compared to saline-treated mice. This adaptive 5-HT1A autoreceptor supersensitivity was associated with decreases in 5-HT levels but no changes of [3H]citalopram binding in brain. Long-term MDMA treatment also induced a 30% decrease in BrdU labelling of proliferating hippocampal cells and an increased immobility duration in the forced swim test suggesting a depressive-like behaviour induced by MDMA treatment. All these effects were abolished in 5-HTT-/- knock-out mice. These data indicated that, in mice, MDMA administration induced a delayed adaptive supersensitivity of 5-HT1A autoreceptors in the DRN, a deficit in hippocampal cell proliferation and a depressive-like behaviour. These 5-HTT-dependent effects, opposite to those of antidepressants, might contribute to MDMA-induced mood disorders.

Partially Defective Store Operated Calcium Entry and Hem(ITAM) Signaling in Platelets of Serotonin Transporter Deficient Mice

PubMed Central

Wolf, Karen; Braun, Attila; Haining, Elizabeth J.; Tseng, Yu-Lun; Kraft, Peter; Schuhmann, Michael K.; Gotru, Sanjeev K.; Chen, Wenchun; Hermanns, Heike M.; Stoll, Guido; Lesch, Klaus-Peter; Nieswandt, Bernhard

2016-01-01

Background Serotonin (5-hydroxytryptamin, 5-HT) is an indolamine platelet agonist, biochemically derived from tryptophan. 5-HT is secreted from the enterochromaffin cells into the gastrointestinal tract and blood. Blood 5-HT has been proposed to regulate hemostasis by acting as a vasoconstrictor and by triggering platelet signaling through 5-HT receptor 2A (5HTR2A). Although platelets do not synthetize 5-HT, they take 5-HT up from the blood and store it in their dense granules which are secreted upon platelet activation. Objective To identify the molecular composite of the 5-HT uptake system in platelets and elucidate the role of platelet released 5-HT in thrombosis and ischemic stroke. Methods: 5-HT transporter knockout mice (5Htt-/-) were analyzed in different in vitro and in vivo assays and in a model of ischemic stroke. Results In 5Htt-/- platelets, 5-HT uptake from the blood was completely abolished and agonist-induced Ca2+ influx through store operated Ca2+ entry (SOCE), integrin activation, degranulation and aggregation responses to glycoprotein VI (GPVI) and C-type lectin-like receptor 2 (CLEC-2) were reduced. These observed in vitro defects in 5Htt-/- platelets could be normalized by the addition of exogenous 5-HT. Moreover, reduced 5-HT levels in the plasma, an increased bleeding time and the formation of unstable thrombi were observed ex vivo under flow and in vivo in the abdominal aorta and carotid artery of 5Htt-/- mice. Surprisingly, in the transient middle cerebral artery occlusion (tMCAO) model of ischemic stroke 5Htt-/- mice showed nearly normal infarct volume and the neurological outcome was comparable to control mice. Conclusion Although secreted platelet 5-HT does not appear to play a crucial role in the development of reperfusion injury after stroke, it is essential to amplify the second phase of platelet activation through SOCE and plays an important role in thrombus stabilization. PMID:26800051

Exercise is associated with reduction in the anxiogenic effect of mCPP on acoustic startle.

PubMed

Fox, James H; Hammack, Sayamwong E; Falls, William A

2008-08-01

Voluntary exercise has been associated with reduced anxiety across several animal models. Manipulation of central 5-HT can alter anxiety-like behaviors and administration of the 5-HT agonist metachlorophenylpiperazine (mCPP) increases anxiety in rodents and humans. To examine whether the anxiolytic effect of exercise is associated with an alteration in 5-HT systems, we examined the anxiogenic effect of mCPP in exercising and nonexercising mice. C57BL/6J mice were given 2 weeks of free access to either a functioning or nonfunctioning running wheel. Mice were then tested for acoustic startle following systemic injection of either 0, 0.1, 0.3, or 1 mg/kg of mCPP. Consistent with its anxiogenic properties, mCPP produced a dose-dependent increase in acoustic startle in nonexercising mice. However, this anxiogenic effect was blunted in exercising mice. These findings suggest that exercise may help to reduce anxiety by altering 5-HT systems, perhaps by down-regulating postsynaptic 5HT 2B/2C receptors.

Tph2 gene deletion enhances amphetamine-induced hypermotility: effect of 5-HT restoration and role of striatal noradrenaline release.

PubMed

Carli, Mirjana; Kostoula, Chrysaugi; Sacchetti, Giuseppina; Mainolfi, Pierangela; Anastasia, Alessia; Villani, Claudia; Invernizzi, Roberto William

2015-11-01

Variants of tryptophan hydroxylase-2 (Tph2), the gene encoding enzyme responsible for the synthesis of brain serotonin (5-HT), have been associated with neuropsychiatric disorders, substance abuse and addiction. This study assessed the effect of Tph2 gene deletion on motor behavior and found that motor activity induced by 2.5 and 5 mg/kg amphetamine was enhanced in Tph2(-/-) mice. Using the in vivo microdialysis technique we found that the ability of amphetamine to stimulate noradrenaline (NA) release in the striatum was reduced by about 50% in Tph2(-/-) mice while the release of dopamine (DA) was not affected. Tph2 deletion did not affect the release of NA and DA in the prefrontal cortex. The role of endogenous 5-HT in enhancing the effect of amphetamine was confirmed showing that treatment with the 5-HT precursor 5-hydroxytryptophan (10 mg/kg) restored tissue and extracellular levels of brain 5-HT and the effects of amphetamine on striatal NA release and motor activity in Tph2(-/-) mice. Treatment with the NA precursor dihydroxyphenylserine (400 mg/kg) was sufficient to restore the effect of amphetamine on striatal NA release and motor activity in Tph2(-/-) mice. These findings indicate that amphetamine-induced hyperactivity is attenuated by endogenous 5-HT through the inhibition of striatal NA release. Tph2(-/-) mice may be a useful preclinical model to assess the role of 5-HT-dependent mechanisms in the action of psychostimulants. Acute sensitivity to the motor effects of amphetamine has been associated to increased risk of psychostimulant abuse. Here, we show that deletion of Tph2, the gene responsible for brain 5-HT synthesis, enhances the motor effect of amphetamine in mice through the inhibition of striatal NA release. This suggests that Tph2(-/-) mice is a useful preclinical model to assess the role of 5-HT-dependent mechanisms in psychostimulants action. Tph2, tryptophan hydroxylase-2. © 2015 International Society for Neurochemistry.

Deletion of CB2 Cannabinoid Receptor Induces Schizophrenia-Related Behaviors in Mice

PubMed Central

Ortega-Alvaro, Antonio; Aracil-Fernández, Auxiliadora; García-Gutiérrez, María S; Navarrete, Francisco; Manzanares, Jorge

2011-01-01

The possible role of the CB2 receptor (CB2r) in psychiatric disorders has been considered. Several animal models use knockout (KO) mice that display schizophrenia-like behaviors and this study evaluated the role of CB2r in the regulation of such behaviors. Mice lacking the CB2r (CB2KO) were challenged in open field, light–dark box, elevated plus-maze, tail suspension, step down inhibitory avoidance, and pre-pulse inhibition tests (PPI). Furthermore, the effects of treatment with cocaine and risperidone were evaluated using the OF and the PPI test. Gene expression of dopamine D2 (D2r), adrenergic-α2C (α2Cr), serotonergic 5-HT2A and 5-HT2C receptors (5-HT2Ar and 5-HT2Cr) were studied by RT-PCR in brain regions related to schizophrenia. Deletion of CB2r decreased motor activity in the OF test, but enhanced response to acute cocaine and produced mood-related alterations, PPI deficit, and cognitive impairment. Chronic treatment with risperidone tended to impair PPI in WT mice, whereas it ‘normalized' the PPI deficit in CB2KO mice. CB2KO mice presented increased D2r and α2Cr gene expressions in the prefrontal cortex (PFC) and locus coeruleus (LC), decreased 5-HT2Cr gene expression in the dorsal raphe (DR), and 5-HT2Ar gene expression in the PFC. Chronic risperidone treatment in WT mice left α2Cr gene expression unchanged, decreased D2r gene expression (15 μg/kg), and decreased 5-HT2Cr and 5-HT2Ar in PFC and DR. In CB2KO, the gene expression of D2r in the PFC, of α2Cr in the LC, and of 5-HT2Cr and 5-HT2Ar in PFC was reduced; 5-HT2Cr and 5-HT2Ar gene expressions in DR were increased after treatment with risperidone. These results suggest that deletion of CB2r has a relation with schizophrenia-like behaviors. Pharmacological manipulation of CB2r may merit further study as a potential therapeutic target for the treatment of schizophrenia-related disorders. PMID:21430651

Delay-dependent working memory impairment in young-adult and aged 5-HT1BKO mice as assessed in a radial-arm water maze.

PubMed

Wolff, Mathieu; Benhassine, Narimane; Costet, Pierre; Hen, Rene; Segu, Louis; Buhot, Marie-Christine

2003-01-01

Serotonin (5-HT) plays a modulatory role in mnemonic functions, especially by interacting with the cholinergic system. The 5-HT1B receptor is a key target of this interaction. The 5-HT1B receptor knockout mice were found previously to exhibit a facilitation in hippocampal-dependent spatial reference memory learning. In the present study, we submitted mice to a delayed spatial working memory task, allowing the introduction of various delays between an exposure trial and a test trial. The 5-HT1BKO and wild-type mice learned the task in a radial-arm water maze (returning to the most recent presented arm containing the escape platform), and exhibited a high level of performance at delays of 0 and 5 min. However, at the delay of 60 min, only 5-HT1BKO mice exhibited an impairment. At a delay of 90 min, all mice were impaired. Treatment by scopolamine (0.8 mg/kg) induced the same pattern of performance in wild type as did the mutation for short (5 min, no impairment) and long (60 min, impairment) delays. The 22-month-old wild-type and knockout mice exhibited an impairment at short delays (5 and 15 min). The effect of the mutation affected both young-adult and aged mice at delays of 15, 30, and 60 min. Neurobiological data show that stimulation of the 5-HT1B receptor inhibits the release of acetylcholine in the hippocampus, but stimulates this in the frontal cortex. This dual function might, at least in part, explain the opposite effect of the mutation on reference memory (facilitation) and delay-dependent working memory (impairment). These results support the idea that cholinergic-serotonergic interactions play an important role in memory processes.

Enhanced serotonin response in the hippocampus of Galphaz protein knock-out mice.

PubMed

Oleskevich, Sharon; Leck, Kwong-Joo; Matthaei, Klaus; Hendry, Ian A

2005-06-21

The serotonin-1A [5-hydroxytryptamine 1A (5HT1A)] receptor is important for emotional and homeostatic processes in the central nervous system. In the hippocampus, the 5HT1A receptor couples to inhibitory Gi/o proteins to decrease pyramidal cell excitability. Here we investigate the 5HT1A receptor in a mouse deficient in the alpha-subunit of Gz protein (Galphaz knock-out). Behavioural tests showed heightened anxiety and depression-like behaviour in the Galphaz knock-out mice. Whole-cell recording in CA1 pyramidal neurons showed a significantly greater 5HT1A receptor-mediated potassium current in Galphaz knock-out mice. The effect was independent of 5HT4 receptors as the slow after-hyperpolarization was unaffected and a slow depolarization was absent in the Galphaz knock-out mice. Other receptors linked to Gi/o proteins [gamma-aminobutyric acid type B receptor (GABAB), adenosine A1 and muscarinic acetylcholine receptors] were not affected in Galphaz knock-out mice. These results suggest that the 5HT1A receptor may be linked to Galphaz protein, as reported previously in cell culture but shown here in an intact neural network.

Alterations in pharmacological and behavioural responses in recombinant mouse line with an increased predisposition to catalepsy: role of the 5-HT1A receptor.

PubMed

Kulikova, E A; Bazovkina, D V; Akulov, A E; Tsybko, A S; Fursenko, D V; Kulikov, A V; Naumenko, V S; Ponimaskin, E; Kondaurova, E M

2016-07-01

One important syndrome of psychiatric disorders in humans is catalepsy. Here, we created mice with different predispositions to catalepsy and analysed their pharmacological and behavioural properties. Two mouse lines, B6-M76C and B6-M76B, were created by transfer of the main locus of catalepsy containing the 5-HT1A receptor gene to the C57BL/6 genetic background. Behaviour, brain morphology, expression of key components of the serotoninergic system, and pharmacological responses to acute and chronic stimulation of the 5-HT1A receptor were compared. B6-M76B mice were not cataleptic, whereas 14% of B6-M76C mice demonstrated catalepsy and decreased depressive-like behaviour. Acute administration of the 5-HT1A receptor agonist 8-OH-DPAT resulted in dose-dependent hypothermia and in decreased locomotion in both lines. Chronic 8-OH-DPAT administration abolished the 5-HT1A receptor-mediated hypothermic response in B6-M76C mice and increased locomotor activity in B6-M76B mice. In addition, 5-HT metabolism was significantly reduced in the hippocampus of B6-M76C mice, and this effect was accompanied by an increased expression of the 5-HT1A receptor. Our findings indicate that transfer of the main locus of hereditary catalepsy containing the 5-HT1A receptor from CBA mice to the C57BL/6 genetic background led to increased postsynaptic and decreased presynaptic functional responses of the 5-HT1A receptor. This characteristic establishes the B6-M76C line as an attractive model for the pharmacological screening of 5-HT1A receptor-related drugs specifically acting on either pre- or postsynaptic receptors. This article is part of a themed section on Updating Neuropathology and Neuropharmacology of Monoaminergic Systems. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v173.13/issuetoc. © 2016 The British Pharmacological Society.

Decrease in serotonin concentration in raphe magnus nucleus and attenuation of morphine analgesia in two mice models of neuropathic pain.

PubMed

Sounvoravong, Sourisak; Nakashima, Mihoko N; Wada, Mitsuhiro; Nakashima, Kenichiro

2004-01-26

The alleviation of neuropathic pain cannot be satisfactorily achieved by treatment with opioids. There is much evidence to indicate that the active site of morphine for inducing effective analgesia is in the raphe magnus nucleus, where serotonin (5-HT, 5-hydroxytryptamine) acts as a primary transmitter. Therefore, we developed the hypothesis that 5-HT released in the raphe magnus nucleus could be related to the effectiveness of morphine in two mice models of neuropathic pain, diabetic (DM)-induced neuropathy and sciatic nerve ligation (SL). Two weeks after a single administration of streptozotocin, or 10 days after sciatic nerve ligation, mice were subcutaneously (s.c.) injected with morphine at 3, 5 and 10 mg/kg. The antinociceptive effect of morphine was estimated in the tail-pinch test; 5-HT content was measured after induction of neuropathic pain by microdialysis followed by high-performance liquid chromatography with electrochemical detection (HPLC-ECD). Morphine produced as insufficient antinociceptive effect in SL mice at all doses compared with that in sham-operated mice, while in DM mice, morphine given s.c. at 5 and 10 mg/kg produced antinociceptive effects compared with those in non-diabetic mice, but not at 3 mg/kg. The 5-HT content of dialysates, expressed as AUC for 75 min, in SL and DM mice was less than that in control mice. However, morphine given s.c. at 5 mg/kg did not significantly affect 5-HT levels in both mice models compared to their controls. These results suggest that the decrease in 5-HT levels in the raphe magnus nucleus may be related to attenuation of the analgesic effect of morphine caused by the abnormal pain state found in diabetes and partial peripheral nerve injury.

Role of Prefrontal Serotonergic and Dopaminergic Systems in Encounter-Induced Hyperactivity in Methamphetamine-Sensitized Mice.

PubMed

Tanaka, Tatsunori; Ago, Yukio; Umehara, Chiaki; Imoto, Emina; Hasebe, Shigeru; Hashimoto, Hitoshi; Takuma, Kazuhiro; Matsuda, Toshio

2017-05-01

Isolation-reared mice show social encounter-induced hyperactivity with activation of prefrontal serotonergic and dopaminergic systems, but it is not known whether this stress response is observed in other pathological conditions. Here we examined whether the social encounter stimulation induces abnormal behavior during withdrawal in chronic methamphetamine-treated mice. To induce methamphetamine-induced behavioral sensitization, male mice were injected with methamphetamine (1 mg/kg) once daily for 7 days. The encounter with an intruder elicited hyperactivity 24 h after the last injection of methamphetamine in methamphetamine-sensitized mice. This response was observed even as long as 2 weeks after withdrawal of methamphetamine. The encounter increased c-Fos expression in the prefrontal cortex, dorsal raphe nucleus and ventral tegmental area in methamphetamine-sensitized mice, while it did not in control mice. Furthermore, the encounter increased extracellular serotonin (5-HT) and dopamine, but not noradrenaline, levels in the prefrontal cortex in methamphetamine-sensitized mice. Local injection of 5,7-dihydroxytryptamine and 6-hydroxydopamine into the prefrontal cortex attenuated encounter-induced hyperactivity in methamphetamine-sensitized mice and it markedly decreased prefrontal 5-HT and dopamine levels, respectively. Pharmacological analysis showed that the encounter-induced hyperactivity is mediated by dopamine D1 receptors and 5-HT2A receptors and attenuated by anxiolytics and antidepressants such as diazepam, osemozotan and selective 5-HT reuptake inhibitors. The effect of paroxetine was blocked by the 5-HT3 receptor antagonist azasetron. The present study shows that psychological stress elicits hyperactivity with activation of prefrontal 5-HT and dopamine systems in methamphetamine-dependent mice and suggests that the abnormal behavior is associated with anxiety and depression. © The Author 2016. Published by Oxford University Press on behalf of CINP.

The serotonergic hallucinogen 5-methoxy-N,N-dimethyltryptamine disrupts cortical activity in a regionally-selective manner via 5-HT(1A) and 5-HT(2A) receptors.

PubMed

Riga, Maurizio S; Bortolozzi, Analia; Campa, Letizia; Artigas, Francesc; Celada, Pau

2016-02-01

5-Methoxy-N,N-dimethyltryptamine (5-MeO-DMT) is a natural hallucinogen, acting as a non-selective serotonin 5-HT(1A)/5-HT(2A)-R agonist. Psychotomimetic agents such as the non-competitive NMDA-R antagonist phencyclidine and serotonergic hallucinogens (DOI and 5-MeO-DMT) disrupt cortical synchrony in the low frequency range (<4 Hz) in rat prefrontal cortex (PFC), an effect reversed by antipsychotic drugs. Here we extend these observations by examining the effect of 5-MeO-DMT on low frequency cortical oscillations (LFCO, <4 Hz) in PFC, visual (V1), somatosensory (S1) and auditory (Au1) cortices, as well as the dependence of these effects on 5-HT(1A)-R and 5-HT(2A)-R, using wild type (WT) and 5-HT(2A)-R knockout (KO2A) anesthetized mice. 5-MeO-DMT reduced LFCO in the PFC of WT and KO2A mice. The effect in KO2A mice was fully prevented by the 5-HT(1A)-R antagonist WAY-100635. Systemic and local 5-MeO-DMT reduced 5-HT release in PFC mainly via 5-HT(1A)-R. Moreover, 5-MeO-DMT reduced LFCO in S1, Au1 and V1 of WT mice and only in V1 of KO2A mice, suggesting the involvement of 5-HT(1A)-R activation in the 5-MeO-DMT-induced disruption of V1 activity. In addition, antipsychotic drugs reversed 5-MeO-DMT effects in WT mice. The present results suggest that the hallucinogen action of 5-MeO-DMT is mediated by simultaneous alterations of the activity of sensory (S1, Au1, V1) and associative (PFC) cortical areas, also supporting a role of 5-HT(1A)-R stimulation in V1 and PFC, in addition to the well-known action on 5-HT(2A)-R. Moreover, the reversal by antipsychotic drugs of 5-MeO-DMT effects adds to previous literature supporting the usefulness of the present model in antipsychotic drug development. Copyright © 2015 Elsevier Ltd. All rights reserved.

Serotonin transporter variant drives preventable gastrointestinal abnormalities in development and function

PubMed Central

Margolis, Kara Gross; Li, Zhishan; Stevanovic, Korey; Saurman, Virginia; Anderson, George M.; Snyder, Isaac; Blakely, Randy D.; Gershon, Michael D.

2016-01-01

Autism spectrum disorder (ASD) is an increasingly common behavioral condition that frequently presents with gastrointestinal (GI) disturbances. It is not clear, however, how gut dysfunction relates to core ASD features. Multiple, rare hyperfunctional coding variants of the serotonin (5-HT) transporter (SERT, encoded by SLC6A4) have been identified in ASD. Expression of the most common SERT variant (Ala56) in mice increases 5-HT clearance and causes ASD-like behaviors. Here, we demonstrated that Ala56-expressing mice display GI defects that resemble those seen in mice lacking neuronal 5-HT. These defects included enteric nervous system hypoplasia, slow GI transit, diminished peristaltic reflex activity, and proliferation of crypt epithelial cells. An opposite phenotype was seen in SERT-deficient mice and in progeny of WT dams given the SERT antagonist fluoxetine. The reciprocal phenotypes that resulted from increased or decreased SERT activity support the idea that 5-HT signaling regulates enteric neuronal development and can, when disturbed, cause long-lasting abnormalities of GI function. Administration of a 5-HT4 agonist to Ala56 mice during development prevented Ala56-associated GI perturbations, suggesting that excessive SERT activity leads to inadequate 5-HT4–mediated neurogenesis. We propose that deficient 5-HT signaling during development may contribute to GI and behavioral features of ASD. The consequences of therapies targeting SERT during pregnancy warrant further evaluation. PMID:27111230

Genotype-dependent activity of tryptophan hydroxylase-2 determines the response to citalopram in a mouse model of depression.

PubMed

Cervo, Luigi; Canetta, Alessandro; Calcagno, Eleonora; Burbassi, Silvia; Sacchetti, Giuseppina; Caccia, Silvio; Fracasso, Claudia; Albani, Diego; Forloni, Gianluigi; Invernizzi, Roberto W

2005-09-07

Polymorphism of tryptophan hydroxylase, the rate-limiting enzyme in the synthesis of brain serotonin (5-HT), is associated with less synthesis of brain 5-HT in DBA/2J and BALB/c than in C57BL/6J and 129/Sv mice. We selected the forced swimming test, a mouse model used to assess the antidepressant potential of drugs, and neurochemical techniques to study strain differences in the response to citalopram, a selective 5-HT reuptake inhibitor. Citalopram reduced immobility time in C57BL/6J and 129/Sv mice but had no such effect in DBA/2J and BALB/c mice. The drug reduced accumulation of 5-hydroxytryptophan (5-HTP), an indicator of 5-HT synthesis, in C57BL/6J and 129/Sv mice but much less in DBA/2J and BALB/c mice. Pretreatment with tryptophan raised 5-HTP accumulation and reinstated the antidepressant-like effect of citalopram in DBA/2J and BALB/c mice, whereas pharmacological inhibition of 5-HT synthesis prevented the effect of citalopram in C57BL/6J and 129/Sv mice. Because there were no strain differences in catecholamine synthesis, locomotor activity, and brain levels of citalopram at the end of the behavioral test, the results suggest that the failure of citalopram to reduce immobility time in DBA/2J and BALB/c mice is attributable to genotype-dependent impairment of 5-HT synthesis. Interstrain comparisons could probably be a useful strategy for understanding the mechanisms underlying the response to selective serotonin reuptake inhibitors.

Activation of serotonin 5-HT2C receptor suppresses behavioral sensitization and naloxone-precipitated withdrawal symptoms in morphine-dependent mice

PubMed Central

Zhang, Gongliang; Wu, Xian; Zhang, Yong-Mei; Liu, Huan; Jiang, Qin; Pang, Gang; Tao, Xinrong; Dong, Liuyi; Stackman, Robert W.

2015-01-01

Opioid abuse and dependence have evolved into an international epidemic as a significant clinical and social problem with devastating consequences. Repeated exposure to the opioid, for example morphine, can induce profound, long-lasting behavioral sensitization and physical dependence, which are thought to reflect neuroplasticity in neural circuitry. Central serotonin (5-HT) neurotransmission participates in the development of dependence on and the expression of withdrawal from morphine. Serotonin 5-HT2C receptor (5-HT2CR) agonists suppress psychostimulant nicotine or cocaine-induced behavioral sensitization and drug-seeking behavior; however, the impact of 5-HT2CR agonists on behaviors relevant to opioid abuse and dependence has not been reported. In the present study, the effects of 5-HT2CR activation on the behavioral sensitization and naloxone-precipitated withdrawal symptoms were examined in mice underwent repeated exposure to morphine. Male mice received morphine (10 mg/kg, s.c.) to develop behavioral sensitization. Lorcaserin, a 5-HT2CR agonist, prevented the induction and expression, but not the development, of morphine-induced behavioral sensitization. Another cohort of mice received increasing doses of morphine over a 7-day period to induce morphine-dependence. Pretreatment of lorcaserin, or the positive control clonidine (an alpha 2-adrenoceptor agonist), ameliorated the naloxone-precipitated withdrawal symptoms. SB 242084, a selective 5-HT2CR antagonist, prevented the lorcaserin-mediated suppression of behavioral sensitization and withdrawal. Chronic morphine treatment was associated with an increase in the expression of 5-HT2CR protein in the ventral tegmental area, locus coeruleus and nucleus accumbens. These findings suggest that 5-HT2CR can modulate behavioral sensitization and withdrawal in morphine-dependent mice, and the activation of 5-HT2CR may represent a new avenue for the treatment of opioid addiction. PMID:26432939

Activation of serotonin 5-HT(2C) receptor suppresses behavioral sensitization and naloxone-precipitated withdrawal symptoms in heroin-treated mice.

PubMed

Wu, Xian; Pang, Gang; Zhang, Yong-Mei; Li, Guangwu; Xu, Shengchun; Dong, Liuyi; Stackman, Robert W; Zhang, Gongliang

2015-10-21

Abuse and dependence to heroin has evolved into a global epidemic as a significant clinical and societal problem with devastating consequences. Repeated exposure to heroin can induce long-lasting behavioral sensitization and withdrawal. Pharmacological activation of 5-HT2C receptors (5-HT2CRs) suppresses psychostimulant-induced drug-seeking and behavioral sensitization. The present study examined the effect of a selective 5-HT2CR agonist lorcaserin on behavioral sensitization and naloxone-precipitated withdrawal symptoms in heroin-treated mice. Male mice received heroin (1.0 mg/kg, s.c.) twice a day for 3 days and then drug treatment was suspended for 5 days. On day 9, a challenge dose of heroin (1.0 mg/kg) was administered to examine the expression of behavioral sensitization. Lorcaserin administered during the development, withdrawal or expression stage suppressed heroin-induced behavioral sensitization on day 9. Another cohort of mice received increasing doses of heroin over a 4.5-day period. Lorcaserin, or the positive control clonidine (an α2-adrenoceptor agonist) suppressed naloxone-precipitated withdrawal symptoms in heroin-treated mice. These findings suggest that activation of 5-HT2CRs suppresses behavioral sensitization and withdrawal in heroin-treated mice. Thus, pharmacological activation of 5-HT2CRs may represent a new avenue for the treatment of heroin addiction. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Activation of serotonin 5-HT2C receptor suppresses behavioral sensitization and naloxone-precipitated withdrawal symptoms in heroin-treated mice

PubMed Central

Li, Guangwu; Xu, Shengchun; Dong, Liuyi; Stackman, Robert W.; Zhang, Gongliang

2015-01-01

Abuse and dependence to heroin has evolved into a global epidemic as a significant clinical and societal problem with devastating consequences. Repeated exposure to heroin can induce long-lasting behavioral sensitization and withdrawal. Pharmacological activation of 5-HT2C receptors (5-HT2CRs) suppresses psychostimulant-induced drug-seeking and behavioral sensitization. The present study examined the effect of a selective 5-HT2CR agonist lorcaserin on behavioral sensitization and naloxone-precipitated withdrawal symptoms in heroin-treated mice. Male mice received heroin (1.0 mg/kg, s.c.) twice a day for 3 days and then drug treatment was suspended for 5 days. On day 9, a challenge dose of heroin (1.0 mg/kg) was administered to examine the expression of behavioral sensitization. Lorcaserin administered during the development, withdrawal or expression stage suppressed heroin-induced behavioral sensitization on day 9. Another cohort of mice received increasing doses of heroin over a 4.5-day period. Lorcaserin, or the positive control clonidine (an α2-adrenoceptor agonist) suppressed naloxone-precipitated withdrawal symptoms in heroin-treated mice. These findings suggest that activation of 5-HT2CRs suppresses behavioral sensitization and withdrawal in heroin-treated mice. Thus, pharmacological activation of 5-HT2CRs may represent a new avenue for the treatment of heroin addiction. PMID:26375926

Positive regulation of raphe serotonin neurons by serotonin 2B receptors.

PubMed

Belmer, Arnauld; Quentin, Emily; Diaz, Silvina L; Guiard, Bruno P; Fernandez, Sebastian P; Doly, Stéphane; Banas, Sophie M; Pitychoutis, Pothitos M; Moutkine, Imane; Muzerelle, Aude; Tchenio, Anna; Roumier, Anne; Mameli, Manuel; Maroteaux, Luc

2018-06-01

Serotonin is a neurotransmitter involved in many psychiatric diseases. In humans, a lack of 5-HT 2B receptors is associated with serotonin-dependent phenotypes, including impulsivity and suicidality. A lack of 5-HT 2B receptors in mice eliminates the effects of molecules that directly target serotonergic neurons including amphetamine derivative serotonin releasers, and selective serotonin reuptake inhibitor antidepressants. In this work, we tested the hypothesis that 5-HT 2B receptors directly and positively regulate raphe serotonin neuron activity. By ex vivo electrophysiological recordings, we report that stimulation by the 5-HT 2B receptor agonist, BW723C86, increased the firing frequency of serotonin Pet1-positive neurons. Viral overexpression of 5-HT 2B receptors in these neurons increased their excitability. Furthermore, in vivo 5-HT 2B -receptor stimulation by BW723C86 counteracted 5-HT 1A autoreceptor-dependent reduction in firing rate and hypothermic response in wild-type mice. By a conditional genetic ablation that eliminates 5-HT 2B receptor expression specifically and exclusively from Pet1-positive serotonin neurons (Htr2b 5-HTKO mice), we demonstrated that behavioral and sensitizing effects of MDMA (3,4-methylenedioxy-methamphetamine), as well as acute behavioral and chronic neurogenic effects of the antidepressant fluoxetine, require 5-HT 2B receptor expression in serotonergic neurons. In Htr2b 5-HTKO mice, dorsal raphe serotonin neurons displayed a lower firing frequency compared to control Htr2b lox/lox mice as assessed by in vivo extracellular recordings and a stronger hypothermic effect of 5-HT 1A -autoreceptor stimulation was observed. The increase in head-twitch response to DOI (2,5-dimethoxy-4-iodoamphetamine) further confirmed the lower serotonergic tone resulting from the absence of 5-HT 2B receptors in serotonin neurons. Together, these observations indicate that the 5-HT 2B receptor acts as a direct positive modulator of serotonin Pet1-positive neurons in an opposite way as the known 5-HT 1A -negative autoreceptor.

Functional Role of Serotonin in Insulin Secretion in a Diet-Induced Insulin-Resistant State

PubMed Central

Kim, Kyuho; Oh, Chang-Myung; Ohara-Imaizumi, Mica; Park, Sangkyu; Namkung, Jun; Yadav, Vijay K.; Tamarina, Natalia A.; Roe, Michael W.; Philipson, Louis H.; Karsenty, Gerard; Nagamatsu, Shinya

2015-01-01

The physiological role of serotonin, or 5-hydroxytryptamine (5-HT), in pancreatic β-cell function was previously elucidated using a pregnant mouse model. During pregnancy, 5-HT increases β-cell proliferation and glucose-stimulated insulin secretion (GSIS) through the Gαq-coupled 5-HT2b receptor (Htr2b) and the 5-HT3 receptor (Htr3), a ligand-gated cation channel, respectively. However, the role of 5-HT in β-cell function in an insulin-resistant state has yet to be elucidated. Here, we characterized the metabolic phenotypes of β-cell-specific Htr2b−/− (Htr2b βKO), Htr3a−/− (Htr3a knock-out [KO]), and β-cell-specific tryptophan hydroxylase 1 (Tph1)−/− (Tph1 βKO) mice on a high-fat diet (HFD). Htr2b βKO, Htr3a KO, and Tph1 βKO mice exhibited normal glucose tolerance on a standard chow diet. After 6 weeks on an HFD, beginning at 4 weeks of age, both Htr3a KO and Tph1 βKO mice developed glucose intolerance, but Htr2b βKO mice remained normoglycemic. Pancreas perfusion assays revealed defective first-phase insulin secretion in Htr3a KO mice. GSIS was impaired in islets isolated from HFD-fed Htr3a KO and Tph1 βKO mice, and 5-HT treatment improved insulin secretion from Tph1 βKO islets but not from Htr3a KO islets. Tph1 and Htr3a gene expression in pancreatic islets was not affected by an HFD, and immunostaining could not detect 5-HT in pancreatic islets from mice fed an HFD. Taken together, these results demonstrate that basal 5-HT levels in β-cells play a role in GSIS through Htr3, which becomes more evident in a diet-induced insulin-resistant state. PMID:25426873

Role of serotonin 5-HT2A receptors in the development of cardiac hypertrophy in response to aortic constriction in mice.

PubMed

Lairez, O; Cognet, T; Schaak, S; Calise, D; Guilbeau-Frugier, C; Parini, A; Mialet-Perez, J

2013-06-01

Serotonin, in addition to its fundamental role as a neurotransmitter, plays a critical role in the cardiovascular system, where it is thought to be involved in the development of cardiac hypertrophy and failure. Indeed, we recently found that mice with deletion of monoamine oxidase A had enhanced levels of blood and cardiac 5-HT, which contributed to exacerbation of hypertrophy in a model of experimental pressure overload. 5-HT2A receptors are expressed in the heart and mediate a hypertrophic response to 5-HT in cardiac cells. However, their role in cardiac remodeling in vivo and the signaling pathways associated are not well understood. In the present study, we evaluated the effect of a selective 5-HT2A receptor antagonist, M100907, on the development of cardiac hypertrophy induced by transverse aortic constriction (TAC). Cardiac 5-HT2A receptor expression was transiently increased after TAC, and was recapitulated in cardiomyocytes, as observed with 5-HT2A in situ labeling by immunohistochemistry. Selective blockade of 5-HT2A receptors prevented the development of cardiac hypertrophy, as measured by echocardiography, cardiomyocyte area and heart weight-to-body weight ratio. Interestingly, activation of calmodulin kinase (CamKII), which is a core mechanism in cardiac hypertrophy, was reduced in cardiac samples from M100907-treated TAC mice compared to vehicle-treated mice. In addition, phosphorylation of histone deacetylase 4 (HDAC4), a downstream partner of CamKII was significantly diminished in M100907-treated TAC mice. Thus, our results show that selective blockade of 5-HT2A receptors has beneficial effect in the development of cardiac hypertrophy through inhibition of the CamKII/HDAC4 pathway.

Dual effects of 5-HT(1a) receptor activation on breathing in neonatal mice.

PubMed

Corcoran, Andrea E; Commons, Kathryn G; Wu, Yuanming; Smith, Jeffrey C; Harris, Michael B; Richerson, George B

2014-01-01

Inhibitory 5-HT(1a) receptors are located on serotonin (5-HT) neurons (autoreceptors) as well as neurons of the respiratory network (heteroreceptors). Thus, effects on breathing of 5-HT(1a) agonists, such as (R)-(+)-8-hydroxy-2-(di-N-propylamino) tetralin (8-OH-DPAT), could either be due to decreased firing of 5-HT neurons or direct effects on the respiratory network. Mice in which the transcription factor LMX1B is genetically deleted selectively in Pet1-1-expressing cells (Lmx1b(f/f/p)) essentially have complete absence of central 5-HT neurons, providing a unique opportunity to separate the effect of activation of downstream 5-HT(1a) heteroreceptors from that of autoreceptors. We used rhythmically active medullary slices from wild-type (WT) and Lmx1b(f/f/p) neonatal mice to differentiate autoreceptor versus heteroreceptor effects of 8-OH-DPAT on hypoglossal nerve respiratory output. 8-OH-DPAT transiently increased respiratory burst frequency in Lmx1b(f/f/p) preparations, but not in WT slices. This excitation was abolished when synaptic inhibition was blocked by GABAergic/glycinergic receptor antagonists. Conversely, after 10 min of application, frequency in Lmx1b(f/f/p) slices was not different from baseline, whereas it was significantly depressed in WT slices. In WT mice in vivo, subcutaneous injection of 8-OH-DPAT produced similar biphasic respiratory effects as in Lmx1b(f/f/p) mice. We conclude that 5-HT1a receptor agonists have two competing effects: rapid stimulation of breathing due to excitation of the respiratory network, and delayed inhibition of breathing due to autoreceptor inhibition of 5-HT neurons. The former effect is presumably due to inhibition of inhibitory interneurons embedded in the respiratory network.

Dual Effects of 5-HT1a Receptor Activation on Breathing in Neonatal Mice

PubMed Central

Commons, Kathryn G.; Wu, Yuanming; Smith, Jeffrey C.; Harris, Michael B.; Richerson, George B.

2014-01-01

Inhibitory 5-HT1a receptors are located on serotonin (5-HT) neurons (autoreceptors) as well as neurons of the respiratory network (heteroreceptors). Thus, effects on breathing of 5-HT1a agonists, such as (R)-(+)-8-hydroxy-2-(di-N-propylamino) tetralin (8-OH-DPAT), could either be due to decreased firing of 5-HT neurons or direct effects on the respiratory network. Mice in which the transcription factor LMX1B is genetically deleted selectively in Pet1-1-expressing cells (Lmx1bf/f/p) essentially have complete absence of central 5-HT neurons, providing a unique opportunity to separate the effect of activation of downstream 5-HT1a heteroreceptors from that of autoreceptors. We used rhythmically active medullary slices from wild-type (WT) and Lmx1bf/f/p neonatal mice to differentiate autoreceptor versus heteroreceptor effects of 8-OH-DPAT on hypoglossal nerve respiratory output. 8-OH-DPAT transiently increased respiratory burst frequency in Lmx1bf/f/p preparations, but not in WT slices. This excitation was abolished when synaptic inhibition was blocked by GABAergic/glycinergic receptor antagonists. Conversely, after 10 min of application, frequency in Lmx1bf/f/p slices was not different from baseline, whereas it was significantly depressed in WT slices. In WT mice in vivo, subcutaneous injection of 8-OH-DPAT produced similar biphasic respiratory effects as in Lmx1bf/f/p mice. We conclude that 5-HT1a receptor agonists have two competing effects: rapid stimulation of breathing due to excitation of the respiratory network, and delayed inhibition of breathing due to autoreceptor inhibition of 5-HT neurons. The former effect is presumably due to inhibition of inhibitory interneurons embedded in the respiratory network. PMID:24381267

Lack of serotonin1B receptor expression leads to age-related motor dysfunction, early onset of brain molecular aging and reduced longevity.

PubMed

Sibille, E; Su, J; Leman, S; Le Guisquet, A M; Ibarguen-Vargas, Y; Joeyen-Waldorf, J; Glorioso, C; Tseng, G C; Pezzone, M; Hen, R; Belzung, C

2007-11-01

Normal aging of the brain differs from pathological conditions and is associated with increased risk for psychiatric and neurological disorders. In addition to its role in the etiology and treatment of mood disorders, altered serotonin (5-HT) signaling is considered a contributing factor to aging; however, no causative role has been identified in aging. We hypothesized that a deregulation of the 5-HT system would reveal its contribution to age-related processes and investigated behavioral and molecular changes throughout adult life in mice lacking the regulatory presynaptic 5-HT(1B) receptor (5-HT(1B)R), a candidate gene for 5-HT-mediated age-related functions. We show that the lack of 5-HT(1B)R (Htr1b(KO) mice) induced an early age-related motor decline and resulted in decreased longevity. Analysis of life-long transcriptome changes revealed an early and global shift of the gene expression signature of aging in the brain of Htr1b(KO) mice. Moreover, molecular changes reached an apparent maximum effect at 18-months in Htr1b(KO) mice, corresponding to the onset of early death in that group. A comparative analysis with our previous characterization of aging in the human brain revealed a phylogenetic conservation of age-effect from mice to humans, and confirmed the early onset of molecular aging in Htr1b(KO) mice. Potential mechanisms appear independent of known central mechanisms (Bdnf, inflammation), but may include interactions with previously identified age-related systems (IGF-1, sirtuins). In summary, our findings suggest that the onset of age-related events can be influenced by altered 5-HT function, thus identifying 5-HT as a modulator of brain aging, and suggesting age-related consequences to chronic manipulation of 5-HT.

Increased Serotonin Signaling Contributes to the Warburg Effect in Pancreatic Tumor Cells Under Metabolic Stress and Promotes Growth of Pancreatic Tumors in Mice.

PubMed

Jiang, Shu-Heng; Li, Jun; Dong, Fang-Yuan; Yang, Jian-Yu; Liu, De-Jun; Yang, Xiao-Mei; Wang, Ya-Hui; Yang, Min-Wei; Fu, Xue-Liang; Zhang, Xiao-Xin; Li, Qing; Pang, Xiu-Feng; Huo, Yan-Miao; Li, Jiao; Zhang, Jun-Feng; Lee, Ho-Young; Lee, Su-Jae; Qin, Wen-Xin; Gu, Jian-Ren; Sun, Yong-Wei; Zhang, Zhi-Gang

2017-07-01

Desmoplasia and poor vascularity cause severe metabolic stress in pancreatic ductal adenocarcinomas (PDACs). Serotonin (5-HT) is a neuromodulator with neurotransmitter and neuroendocrine functions that contributes to tumorigenesis. We investigated the role of 5-HT signaling in the growth of pancreatic tumors. We measured the levels of proteins that regulate 5-HT synthesis, packaging, and degradation in pancreata from Kras G12D/+ /Trp53 R172H/+ /Pdx1-Cre (KPC) mice, which develop pancreatic tumors, as well as in PDAC cell lines and a tissue microarray containing 81 human PDAC samples. We also analyzed expression levels of proteins involved in 5-HT synthesis and degradation by immunohistochemical analysis of a tissue microarray containing 311 PDAC specimens, and associated expression levels with patient survival times. 5-HT level in 14 matched PDAC tumor and non-tumor tissues were analyzed by ELISA. PDAC cell lines were incubated with 5-HT and cell survival and apoptosis were measured. We analyzed expression of the 5-HT receptor HTR2B in PDAC cells and effects of receptor agonists and antagonists, as well as HTR2B knockdown with small hairpin RNAs. We determined the effects of 5-HT stimulation on gene expression profiles of BxPC-3 cells. Regulation of glycolysis by 5-HT signaling via HTR2B was assessed by immunofluorescence and immunoprecipitation analyses, as well as by determination of the extracellular acid ratio, glucose consumption, and lactate production. Primary PDACs, with or without exposure to SB204741 (a selective antagonist of HTR2B), were grown as xenograft tumors in mice, and SB204741 was administered to tumor-bearing KPC mice; tumor growth and metabolism were measured by imaging analyses. In immunohistochemical analysis of a tissue microarray of PDAC specimens, increased levels of TPH1 and decreased level of MAOA, which regulate 5-HT synthesis and degradation, correlated with stage and size of PDACs and shorter patient survival time. We found levels of 5-HT to be increased in human PDAC tissues compared with non-tumor pancreatic tissues, and PDAC cell lines compared with non-transformed pancreatic cells. Incubation of PDAC cell lines with 5-HT increased proliferation and prevented apoptosis. Agonists of HTR2B, but not other 5-HT receptors, promoted proliferation and prevented apoptosis of PDAC cells. Knockdown of HTR2B in PDAC cells, or incubation of cells with HTR2B inhibitors, reduced their growth as xenograft tumors in mice. We observed a correlation between 5-HT and glycolytic flux in PDAC cells; levels of metabolic enzymes involved in glycolysis, the phosphate pentose pathway, and hexosamine biosynthesis pathway increased significantly in PDAC cells following 5-HT stimulation. 5-HT stimulation led to formation of the HTR2B-LYN-p85 complex, which increased PI3K-Akt-mTOR signaling and the Warburg effect by increasing protein levels of MYC and HIF1A. Administration of SB204741 to KPC mice slowed growth and metabolism of established pancreatic tumors and prolonged survival of the mice. Human PDACs have increased levels of 5-HT, and PDAC cells increase expression of its receptor, HTR2B. These increases allow for tumor glycolysis under metabolic stress and promote growth of pancreatic tumors and PDAC xenograft tumors in mice. Copyright © 2017 AGA Institute. Published by Elsevier Inc. All rights reserved.

Role of serotonin in the intestinal mucosal epithelium barrier in weaning mice undergoing stress-induced diarrhea.

PubMed

Dong, Yulan; Wang, Zixu; Qin, Zhuoming; Cao, Jing; Chen, Yaoxing

2018-02-01

Stress-induced diarrhea is a frequent and challenging threat to humans and domestic animals. Serotonin (5-HT) has been shown to be involved in the pathological process of stress-induced diarrhea. However, the role of 5-HT in stress-induced diarrhea remains unclear. A stress-induced diarrhea model was established in 21-day-old ICR weaning mice through an intragastric administration of 0.25 mL of 0.4 g/mL folium sennae and restraint of the hind legs with adhesive tape for 4 h to determine whether 5-HT regulates the mucosal barrier to cause diarrhea. Mice with decreased levels of 5-HT were pretreated with an intraperitoneal injection of 300 mg/kg p-chlorophenylalanine (PCPA), a 5-HT synthesis inhibitor. After 5 days of treatment, the stress level, body weight and intestinal mucosal morphology indexes were measured. Compared to the controls, the mice with stress-induced diarrhea displayed a stress reaction, with increased corticosterone levels, as well as increased 5-HT-positive cells. However, the mice with stress-induced diarrhea exhibited decreased body weights, villus height to crypt depth ratios (V/C), and Occludin and Claudin1 expression. The PCPA injection reversed these effects in mice with different degrees of stress-induced diarrhea. Based on these findings, inhibition of 5-HT synthesis relieved the stress response and improved the health of the intestinal tract, including both the intestinal absorption capacity, as determined by the villus height and crypt depth, and the mucosal barrier function, as determined by the tight junction proteins of epithelial cell.

Role of 5-HT3 Receptor on Food Intake in Fed and Fasted Mice

PubMed Central

Li, Bingjin; Shao, Dongyuan; Luo, Yungang; Wang, Pu; Liu, Changhong; Zhang, Xingyi; Cui, Ranji

2015-01-01

Background Many studies have shown that 5-hydroxytryptamine (5-HT) receptor subtypes are involved in the regulation of feeding behavior. However, the relative contribution of 5-HT3 receptor remains unclear. The present study was aimed to investigate the role of 5-HT3 receptor in control of feeding behavior in fed and fasted mice. Methodology/Principal Findings Food intake and expression of c-Fos, tyrosine hydroxylase (TH), proopiomelanocortin (POMC) and 5-HT in the brain were examined after acute treatment with 5-HT3 receptor agonist SR-57227 alone or in combination with 5-HT3 receptor antagonist ondansetron. Food intake was significantly inhibited within 3 h after acute treatment with SR 57227 in fasted mice but not fed mice, and this inhibition was blocked by ondansetron. Immunohistochemical study revealed that fasting-induced c-Fos expression was further enhanced by SR 57227 in the brainstem and the hypothalamus, and this enhancement was also blocked by ondansetron. Furthermore, the fasting-induced downregulation of POMC expression in the hypothalamus and the TH expression in the brain stem was blocked by SR 57227 in the fasted mice, and this effect of SR 57227 was also antagonized by ondansetron. Conclusion/Significance Taken together, our findings suggest that the effect of SR 57227 on the control of feeding behavior in fasted mice may be, at least partially, related to the c-Fos expression in hypothalamus and brain stem, as well as POMC system in the hypothalamus and the TH system in the brain stem. PMID:25789930

Seizure-dependent mTOR activation in 5-HT neurons promotes autism-like behaviors in mice.

PubMed

McMahon, John J; Yu, Wilson; Yang, Jun; Feng, Haihua; Helm, Meghan; McMahon, Elizabeth; Zhu, Xinjun; Shin, Damian; Huang, Yunfei

2015-01-01

Epilepsy and autism spectrum disorder (ASD) are common comorbidities of one another. Despite the prevalent correlation between the two disorders, few studies have been able to elucidate a mechanistic link. We demonstrate that forebrain specific Tsc1 deletion in mice causes epilepsy and autism-like behaviors, concomitant with disruption of 5-HT neurotransmission. We find that epileptiform activity propagates to the raphe nuclei, resulting in seizure-dependent hyperactivation of mTOR in 5-HT neurons. To dissect whether mTOR hyperactivity in 5-HT neurons alone was sufficient to recapitulate an autism-like phenotype we utilized Tsc1flox/flox;Slc6a4-cre mice, in which mTOR is restrictively hyperactivated in 5-HT neurons. Tsc1flox/flox;Slc6a4-cre mice displayed alterations of the 5-HT system and autism-like behaviors, without causing epilepsy. Rapamycin treatment in these mice was sufficient to rescue the phenotype. We conclude that the spread of seizure activity to the brainstem is capable of promoting hyperactivation of mTOR in the raphe nuclei, which in turn promotes autism-like behaviors. Thus our study provides a novel mechanism describing how epilepsy can contribute to the development of autism-like behaviors, suggesting new therapeutic strategies for autism. Copyright © 2015 Elsevier Inc. All rights reserved.

Seizure-dependent mTOR activation in 5-HT neurons promotes autism-like behaviors in mice

PubMed Central

McMahon, John J.; Yu, Wilson; Yang, Jun; Feng, Haihua; Helm, Meghan; McMahon, Elizabeth; Zhu, Xinjun; Shin, Damian; Huang, Yunfei

2014-01-01

Epilepsy and autism spectrum disorder (ASD) are common comorbidities of one another. Despite the prevalent correlation between the two disorders, few studies have been able to elucidate a mechanistic link. We demonstrate that forebrain specific Tsc1 deletion in mice causes epilepsy and autism-like behaviors, concomitant with disruption of 5-HT neurotransmission. We find that epileptiform activity propagates to the raphe nuclei, resulting in seizure-dependent hyperactivation of mTOR in 5-HT neurons. To dissect whether mTOR hyperactivity in 5-HT neurons alone was sufficient to recapitulate an autism-like phenotype we utilized Tsc1flox/flox;Slc6a4-cre mice, in which mTOR is restrictively hyperactivated in 5-HT neurons. Tsc1flox/flox;Slc6a4-cre mice displayed alterations of the 5-HT system and autism-like behaviors, without causing epilepsy. Rapamycin treatment in these mice was sufficient to rescue the phenotype. We conclude that the spread of seizure activity to the brainstem is capable of promoting hyperactivation of mTOR in the raphe nuclei, which in turn promotes autism-like behaviors. Thus our study provides a novel mechanism describing how epilepsy can contribute to the development of autism-like behaviors, suggesting new therapeutic strategies for autism. PMID:25315683

The effects of glycogen synthase kinase-3beta in serotonin neurons.

PubMed

Zhou, Wenjun; Chen, Ligong; Paul, Jodi; Yang, Sufen; Li, Fuzeng; Sampson, Karen; Woodgett, Jim R; Beaulieu, Jean Martin; Gamble, Karen L; Li, Xiaohua

2012-01-01

Glycogen synthase kinase-3 (GSK3) is a constitutively active protein kinase in brain. Increasing evidence has shown that GSK3 acts as a modulator in the serotonin neurotransmission system, including direct interaction with serotonin 1B (5-HT1B) receptors in a highly selective manner and prominent modulating effect on 5-HT1B receptor activity. In this study, we utilized the serotonin neuron-selective GSK3β knockout (snGSK3β-KO) mice to test if GSK3β in serotonin neurons selectively modulates 5-HT1B autoreceptor activity and function. The snGSK3β-KO mice were generated by crossbreeding GSK3β-floxed mice and ePet1-Cre mice. These mice had normal growth and physiological characteristics, similar numbers of tryptophan hydroxylase-2 (TpH2)-expressing serotonin neurons, and the same brain serotonin content as in littermate wild type mice. However, the expression of GSK3β in snGSK3β-KO mice was diminished in TpH2-expressing serotonin neurons. Compared to littermate wild type mice, snGSK3β-KO mice had a reduced response to the 5-HT1B receptor agonist anpirtoline in the regulation of serotonergic neuron firing, cAMP production, and serotonin release, whereas these animals displayed a normal response to the 5-HT1A receptor agonist 8-OH-DPAT. The effect of anpirtoline on the horizontal, center, and vertical activities in the open field test was differentially affected by GSK3β depletion in serotonin neurons, wherein vertical activity, but not horizontal activity, was significantly altered in snGSK3β-KO mice. In addition, there was an enhanced anti-immobility response to anpirtoline in the tail suspension test in snGSK3β-KO mice. Therefore, results of this study demonstrated a serotonin neuron-targeting function of GSK3β by regulating 5-HT1B autoreceptors, which impacts serotonergic neuron firing, serotonin release, and serotonin-regulated behaviors.

Hydroxytyrosol prevents diet-induced metabolic syndrome and attenuates mitochondrial abnormalities in obese mice.

PubMed

Cao, Ke; Xu, Jie; Zou, Xuan; Li, Yuan; Chen, Cong; Zheng, Adi; Li, Hao; Li, Hua; Szeto, Ignatius Man-Yau; Shi, Yujie; Long, Jiangang; Liu, Jiankang; Feng, Zhihui

2014-02-01

A Mediterranean diet rich in olive oil has profound influence on health outcomes including metabolic syndrome. However, the active compound and detailed mechanisms still remain unclear. Hydroxytyrosol (HT), a major polyphenolic compound in virgin olive oil, has received increased attention for its antioxidative activity and regulation of mitochondrial function. Here, we investigated whether HT is the active compound in olive oil exerting a protective effect against metabolic syndrome. In this study, we show that HT could prevent high-fat-diet (HFD)-induced obesity, hyperglycemia, hyperlipidemia, and insulin resistance in C57BL/6J mice after 17 weeks supplementation. Within liver and skeletal muscle tissues, HT could decrease HFD-induced lipid deposits through inhibition of the SREBP-1c/FAS pathway, ameliorate HFD-induced oxidative stress by enhancing antioxidant enzyme activities, normalize expression of mitochondrial complex subunits and mitochondrial fission marker Drp1, and eventually inhibit apoptosis activation. Moreover, in muscle tissue, the levels of mitochondrial carbonyl protein were decreased and mitochondrial complex activities were significantly improved by HT supplementation. In db/db mice, HT significantly decreased fasting glucose, similar to metformin. Notably, HT decreased serum lipid, at which metformin failed. Also, HT was more effective at decreasing the oxidation levels of lipids and proteins in both liver and muscle tissue. Similar to the results in the HFD model, HT decreased muscle mitochondrial carbonyl protein levels and improved mitochondrial complex activities in db/db mice. Our study links the olive oil component HT to diabetes and metabolic disease through changes that are not limited to decreases in oxidative stress, suggesting a potential pharmaceutical or clinical use of HT in metabolic syndrome treatment. Copyright © 2013 Elsevier Inc. All rights reserved.

PKCδ Knockout Mice Are Protected from Dextromethorphan-Induced Serotonergic Behaviors in Mice: Involvements of Downregulation of 5-HT1A Receptor and Upregulation of Nrf2-Dependent GSH Synthesis.

PubMed

Tran, Hai-Quyen; Lee, Youngho; Shin, Eun-Joo; Jang, Choon-Gon; Jeong, Ji Hoon; Mouri, Akihiro; Saito, Kuniaki; Nabeshima, Toshitaka; Kim, Hyoung-Chun

2018-02-22

We investigated whether a specific serotonin (5-HT) receptor-mediated mechanism was involved in dextromethorphan (DM)-induced serotonergic behaviors. We firstly observed that the activation of 5-HT 1A receptor, but not 5-HT 2A receptor, contributed to DM-induced serotonergic behaviors in mice. We aimed to determine whether the upregulation of 5-HT 1A receptor induced by DM facilitates the specific induction of certain PKC isoform, because previous reports suggested that 5-HT 1A receptor activates protein kinase C (PKC). A high dose of DM (80 mg/kg, i.p.) induced a selective induction of PKCδ out of PKCα, PKCβI, PKCβII, PKCξ, and PKCδ in the hypothalamus of wild-type (WT) mice. More importantly, 5-HT 1A receptor co-immunoprecipitated PKCδ in the presence of DM. Consistently, rottlerin, a pharmacological inhibitor of PKCδ, or PKCδ knockout significantly protected against increases in 5-HT 1A receptor gene expression, 5-HT turnover rate, and serotonergic behaviors induced by DM. Treatment with DM resulted in an initial increase in nuclear factor erythroid-2-related factor 2 (Nrf2) nuclear translocation and DNA-binding activity, γ-glutamylcysteine (GCL) mRNA expression, and glutathione (GSH) level. This compensative induction was further potentiated by rottlerin or PKCδ knockout. However, GCL mRNA and GSH/GSSG levels were decreased 6 and 12 h post-DM. These decreases were attenuated by PKCδ inhibition. Our results suggest that interaction between 5-HT 1A receptor and PKCδ is critical for inducing DM-induced serotonergic behaviors and that inhibition of PKCδ attenuates the serotonergic behaviors via downregulation of 5-HT 1A receptor and upregulation of Nrf2-dependent GSH synthesis.

Severe Serotonin Depletion after Conditional Deletion of the Vesicular Monoamine Transporter 2 Gene in Serotonin Neurons: Neural and Behavioral Consequences

PubMed Central

Narboux-Nême, Nicolas; Sagné, Corinne; Doly, Stephane; Diaz, Silvina L; Martin, Cédric B P; Angenard, Gaelle; Martres, Marie-Pascale; Giros, Bruno; Hamon, Michel; Lanfumey, Laurence; Gaspar, Patricia; Mongeau, Raymond

2011-01-01

The vesicular monoamine transporter type 2 gene (VMAT2) has a crucial role in the storage and synaptic release of all monoamines, including serotonin (5-HT). To evaluate the specific role of VMAT2 in 5-HT neurons, we produced a conditional ablation of VMAT2 under control of the serotonin transporter (slc6a4) promoter. VMAT2sert−cre mice showed a major (−95%) depletion of 5-HT levels in the brain with no major alterations in other monoamines. Raphe neurons contained no 5-HT immunoreactivity in VMAT2sert−cre mice but developed normal innervations, as assessed by both tryptophan hydroxylase 2 and 5-HT transporter labeling. Increased 5-HT1A autoreceptor coupling to G protein, as assessed with agonist-stimulated [35S]GTP-γ-S binding, was observed in the raphe area, indicating an adaptive change to reduced 5-HT transmission. Behavioral evaluation in adult VMAT2sert−cre mice showed an increase in escape-like reactions in response to tail suspension and anxiolytic-like response in the novelty-suppressed feeding test. In an aversive ultrasound-induced defense paradigm, VMAT2sert−cre mice displayed a major increase in escape-like behaviors. Wild-type-like defense phenotype could be rescued by replenishing intracellular 5-HT stores with chronic pargyline (a monoamine oxidase inhibitor) treatment. Pargyline also allowed some form of 5-HT release, although in reduced amounts, in synaptosomes from VMAT2sert−cre mouse brain. These findings are coherent with the notion that 5-HT has an important role in anxiety, and provide new insights into the role of endogenous 5-HT in defense behaviors. PMID:21814181

Abrogated Freud-1/CC2D1A repression of 5-HT1A autoreceptors induces fluoxetine-resistant anxiety/depression-like behavior

PubMed Central

Vahid-Ansari, Faranak; Daigle, Mireille; Manzini, M. Chiara; Tanaka, Kenji F.; Hen, René; Geddes, Sean D.; Béïque, Jean-Claude; James, Jonathan; Merali, Zul; Albert, Paul R.

2017-01-01

Freud-1/CC2D1A represses the gene transcription of serotonin-1A (5-HT1A) autoreceptors, which negatively regulate 5-HT tone. To test the role of Freud-1 in vivo, we generated mice with adulthood conditional knockout of Freud-1 in 5-HT neurons (cF1ko). In cF1ko mice, 5-HT1A autoreceptor protein, binding and hypothermia response were increased, with reduced 5-HT content and neuronal activity in the dorsal raphe. The cF1ko mice displayed increased anxiety- and depression-like behavior that was resistant to chronic antidepressant (fluoxetine) treatment. Using conditional Freud-1/5-HT1A double knockout (cF1/1A dko) to disrupt both Freud-1 and 5-HT1A genes in 5-HT neurons, no increase in anxiety- or depression-like behaviour was seen upon knockout of Freud-1 on the 5-HT1A autoreceptor-negative background, rather a reduction in depression-like behaviour emerged. These studies implicate transcriptional dys-regulation of 5-HT1A autoreceptors by the repressor Freud-1 in anxiety and depression and provide a clinically relevant genetic model of antidepressant resistance. Targeting specific transcription factors like Freud-1 to restore transcriptional balance may augment response to antidepressant treatment. PMID:29101244

Mouse strain differences in immobility and sensitivity to fluvoxamine and desipramine in the forced swimming test: analysis of serotonin and noradrenaline transporter binding.

PubMed

Sugimoto, Yumi; Kajiwara, Yoshinobu; Hirano, Kazufumi; Yamada, Shizuo; Tagawa, Noriko; Kobayashi, Yoshiharu; Hotta, Yoshihiro; Yamada, Jun

2008-09-11

Strain differences in immobility time in the forced swimming test were investigated in five strains of mice, namely, ICR, ddY, C57BL/6, DBA/2 and BALB/c mice. There were significant strain differences. The immobility times of ICR, ddY and C57BL/6 mice were longer than those of DBA/2 and BALB/c mice. Immobility times were not significantly related to locomotor activity in these strains. There were also differences in sensitivity to the selective serotonin reuptake inhibitor (SSRI) fluvoxamine. In ICR, ddY and C57BL/6 mice, fluvoxamine did not affect immobility time, while it reduced the immobility time of DBA/2 and BALB/c mice dose-dependently. The noradrenaline reuptake inhibitor desipramine decreased immobility time in all strains of mice. Serotonin (5-HT) transporter binding in the brains of all five strains of mice was also investigated. Analysis of 5-HT transporter binding revealed significant strain differences, being lower in DBA/2 and BALB/c mice than in other strains of mice. The amount of 5-HT transporter binding was correlated to baseline immobility time. However, there was no significant relation between noradrenaline transporter binding and immobility time. These results suggest that the duration of baseline immobility depends on the levels of 5-HT transporter binding, leading to apparent strain differences in immobility time in the forced swimming test. Furthermore, differences in 5-HT transporter binding may cause variations in responses to fluvoxamine.

Hypoxia facilitates neurogenic dural plasma protein extravasation in mice: a novel animal model for migraine pathophysiology

PubMed Central

Hunfeld, Anika; Segelcke, Daniel; Bäcker, Ingo; Mecheri, Badreddine; Hemmer, Kathrin; Dlugosch, Elisabeth; Andriske, Michael; Paris, Frank; Zhu, Xinran; Lübbert, Hermann

2015-01-01

Migraine animal models generally mimic the onset of attacks and acute treatment processes. A guinea pig model used the application of meta-chlorophenylpiperazine (mCPP) to trigger immediate dural plasma protein extravasation (PPE) mediated by 5-HT2B receptors. This model has predictive value for antimigraine drugs but cannot explain the delayed onset of efficacy of 5-HT2B receptor antagonists when clinically used for migraine prophylaxis. We found that mCPP failed to induce dural PPE in mice. Considering the role 5-HT2B receptors play in hypoxia-induced pulmonary vessel muscularization, we were encouraged to keep mice under hypoxic conditions and tested whether this treatment will render them susceptible to mCPP-induced dural PPE. Following four-week of hypoxia, PPE, associated with increased transendothelial transport, was induced by mCPP. The effect was blocked by sumatriptan. Chronic application of 5-HT2B receptor or nitric oxide synthase blockers during hypoxia prevented the development of susceptibility. Here we present a migraine model that distinguishes between a migraine-like state (hypoxic mice) and normal, normoxic mice and mimics processes that are related to chronic activation of 5-HT2B receptors under hypoxia. It seems striking, that chronic endogenous activation of 5-HT2B receptors is crucial for the sensitization since 5-HT2B receptor antagonists have strong, albeit delayed migraine prophylactic efficacy. PMID:26644235

12/15-Lipoxygenase Inhibition or Knockout Reduces Warfarin-Associated Hemorrhagic Transformation After Experimental Stroke.

PubMed

Liu, Yu; Zheng, Yi; Karatas, Hulya; Wang, Xiaoying; Foerch, Christian; Lo, Eng H; van Leyen, Klaus

2017-02-01

For stroke prevention, patients with atrial fibrillation typically receive oral anticoagulation. The commonly used anticoagulant warfarin increases the risk of hemorrhagic transformation (HT) when a stroke occurs; tissue-type plasminogen activator treatment is therefore restricted in these patients. This study was designed to test the hypothesis that 12/15-lipoxygenase (12/15-LOX) inhibition would reduce HT in warfarin-treated mice subjected to experimental stroke. Warfarin was dosed orally in drinking water, and international normalized ratio values were determined using a Coaguchek device. C57BL6J mice or 12/15-LOX knockout mice were subjected to transient middle cerebral artery occlusion with 3 hours severe ischemia (model A) or 2 hours ischemia and tissue-type plasminogen activator infusion (model B), with or without the 12/15-LOX inhibitor ML351. Hemoglobin was determined in brain homogenates, and hemorrhage areas on the brain surface and in brain sections were measured. 12/15-LOX expression was detected by immunohistochemistry. Warfarin treatment resulted in reproducible increased international normalized ratio values and significant HT in both models. 12/15-LOX knockout mice suffered less HT after severe ischemia, and ML351 reduced HT in wild-type mice. When normalized to infarct size, ML351 still independently reduced hemorrhage. HT after tissue-type plasminogen activator was similarly reduced by ML351. In addition to its benefits in infarct size reduction, 12/15-LOX inhibition also may independently reduce HT in warfarin-treated mice. ML351 should be further evaluated as stroke treatment in anticoagulated patients suffering a stroke, either alone or in conjunction with tissue-type plasminogen activator. © 2017 American Heart Association, Inc.

Repeated swim impairs serotonin clearance via a corticosterone-sensitive mechanism: organic cation transporter 3, the smoking gun.

PubMed

Baganz, Nicole; Horton, Rebecca; Martin, Kathryn; Holmes, Andrew; Daws, Lynette C

2010-11-10

Activation of the hypothalamic-pituitary-adrenal (HPA) axis is associated with increased extracellular serotonin (5-HT) in limbic brain regions. The mechanism through which this occurs remains unclear. One way could be via HPA axis-dependent impairment of serotonin transporter (SERT) function, the high-affinity uptake mechanism for 5-HT. Consistent with this idea, we found that 5-HT clearance rate in hippocampus was dramatically reduced in mice exposed to repeated swim, a stimulus known to activate the HPA axis. However, this phenomenon also occurred in mice lacking SERT, ruling out SERT as a mechanism. The organic cation transporter 3 (OCT3) is emerging as an important regulator of brain 5-HT. Moreover, corticosterone, which is released upon HPA axis activation, blocks 5-HT uptake by OCT3. Repeated swim produced a persistent elevation in plasma corticosterone, and, consistent with prolonged blockade by corticosterone, we found that OCT3 expression and function were reduced in these mice. Importantly, this effect of repeated swim to reduce 5-HT clearance rate was corticosterone dependent, as evidenced by its absence in adrenalectomized mice, in which plasma corticosterone levels were essentially undetectable. Behaviorally, mice subjected to repeated swim spent less time immobile in the tail suspension test than control mice, but responded similarly to SERT- and norepinephrine transporter-selective antidepressants. Together, these results show that reduced 5-HT clearance following HPA axis activation is likely mediated, at least in part, by the corticosterone-sensitive OCT3, and that drugs developed to selectively target OCT3 (unlike corticosterone) may be candidates for the development of novel antidepressant medications.

Early postnatal inhibition of serotonin synthesis results in long-term reductions of perseverative behaviors, but not aggression, in MAO A-deficient mice

PubMed Central

Bortolato, Marco; Godar, Sean C.; Tambaro, Simone; Li, Felix G.; Devoto, Paola; Coba, Marcelo P.; Chen, Kevin; Shih, Jean C.

2013-01-01

Monoamine oxidase (MAO) A, the major enzyme catalyzing the oxidative degradation of serotonin (5-hydroxytryptamine, 5-HT), plays a key role in emotional regulation. In humans and mice, MAO-A deficiency results in high 5-HT levels, antisocial, aggressive, and perseverative behaviors. We previously showed that the elevation in brain 5-HT levels in MAO-A knockout (KO) mice is particularly marked during the first two weeks of postnatal life. Building on this finding, we hypothesized that the reduction of 5-HT levels during these early stages may lead to enduring attenuations of the aggression and other behavioral aberrances observed in MAO-A KO mice. To test this possibility, MAO-A KO mice were treated with daily injections of a 5-HT synthesis blocker, the tryptophan hydroxylase inhibitor p-chloro-phenylalanine (pCPA, 300 mg/kg/day, IP), from postnatal day 1 through 7. As expected, this regimen significantly reduced 5-HT forebrain levels in MAO-A KO pups. These neurochemical changes persisted throughout adulthood, and resulted in significant reductions in marble-burying behavior, as well as increases in spontaneous alternations within a T-maze. Conversely, pCPA-treated MAO-A KO mice did not exhibit significant changes in anxiety-like behaviors in a novel open-field and elevated plus-maze; furthermore, this regimen did not modify their social deficits, aggressive behaviors and impairments in tactile sensitivity. Treatment with pCPA from postnatal day 8 through 14 elicited similar, yet milder, behavioral effects on marble-burying behavior. These results suggest that early developmental enhancements in 5-HT levels have long-term effects on the modulation of behavioral flexibility associated with MAO-A deficiency. PMID:23871843

Enhanced Stress Response in 5-HT1AR Overexpressing Mice: Altered HPA Function and Hippocampal Long-Term Potentiation.

PubMed

Pilar-Cuéllar, Fuencisla; Vidal, Rebeca; Díaz, Álvaro; Garro-Martínez, Emilio; Linge, Raquel; Castro, Elena; Haberzettl, Robert; Fink, Heidrun; Bert, Bettina; Brosda, Jan; Romero, Beatriz; Crespo-Facorro, Benedicto; Pazos, Ángel

2017-11-15

Postsynaptic 5-HT 1A receptors (5-HT 1A R) play an important role in anxiety and stress, although their contribution is still controversial. Previous studies report that mice overexpressing postsynaptic 5-HT 1A Rs show no changes in basal anxiety, though the influence of stress conditions has not been addressed yet. In this study, we used this animal model to evaluate the role of 5-HT 1A Rs in anxiety response after pre-exposure to an acute stressor. Under basal conditions, 5-HT 1A R overexpressing animals presented high corticosterone levels and a lower mineralocorticoid/glucocorticoid receptor ratio. After pre-exposure to a single stressor, they showed a high anxiety-like response, associated with a blunted increase in corticosterone levels and higher c-Fos activation in the prefrontal cortex. Moreover, these mice also presented a lack of downregulation of hippocampal long-term potentiation after stress exposure. Therefore, higher postsynaptic 5-HT 1A R activation might predispose to a high anxious phenotype and an impaired stress coping behavior.

5-HT2A receptor antagonists improve motor impairments in the MPTP mouse model of Parkinson's disease.

PubMed

Ferguson, Marcus C; Nayyar, Tultul; Deutch, Ariel Y; Ansah, Twum A

2010-01-01

Clinical observations have suggested that ritanserin, a 5-HT(2A/C) receptor antagonist may reduce motor deficits in persons with Parkinson's Disease (PD). To better understand the potential antiparkinsonian actions of ritanserin, we compared the effects of ritanserin with the selective 5-HT(2A) receptor antagonist M100907 and the selective 5-HT(2C) receptor antagonist SB 206553 on motor impairments in mice treated with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). MPTP-treated mice exhibited decreased performance on the beam-walking apparatus. These motor deficits were reversed by acute treatment with L-3,4-dihydroxyphenylalanine (levodopa). Both the mixed 5-HT(2A/C) antagonist ritanserin and the selective 5-HT(2A) antagonist M100907 improved motor performance on the beam-walking apparatus. In contrast, SB 206553 was ineffective in improving the motor deficits in MPTP-treated mice. These data suggest that 5-HT(2A) receptor antagonists may represent a novel approach to ameliorate motor symptoms of Parkinson's disease. Published by Elsevier Ltd.

5-HT2A receptor antagonists improve motor impairments in the MPTP mouse model of Parkinson's disease

PubMed Central

Ferguson, Marcus C.; Nayyar, Tultul; Deutch, Ariel Y.; Ansah, Twum A.

2010-01-01

Clinical observations have suggested that ritanserin, a 5-HT2A/C receptor antagonist may reduce motor deficits in persons with Parkinson's Disease (PD). To better understand the potential antiparkinsonian actions of ritanserin, we compared the effects of ritanserin with the selective 5-HT2A receptor antagonist M100907 and the selective 5-HT2C receptor antagonist SB 206553 on motor impairments in mice treated with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). MPTP-treated mice exhibited decreased performance on the beam-walking apparatus. These motor deficits were reversed by acute treatment with L-3,4-dihydroxyphenylalanine (levodopa). Both the mixed 5-HT2A/C antagonist ritanserin and the selective 5-HT2A antagonist M100907 improved motor performance on the beam-walking apparatus. In contrast, SB 206553 was ineffective in improving the motor deficits in MPTP-treated mice. These data suggest that 5-HT2A receptor antagonists may represent a novel approach to ameliorate motor symptoms of Parkinson's disease. PMID:20361986

A higher body temperature is associated with haemorrhagic transformation in patients with acute stroke untreated with recombinant tissue-type plasminogen activator (rtPA).

PubMed

Leira, Rogelio; Sobrino, Tomás; Blanco, Miguel; Campos, Francisco; Rodríguez-Yáñez, Manuel; Castellanos, Mar; Moldes, Octavio; Millán, Mónica; Dávalos, Antoni; Castillo, José

2012-02-01

Higher body temperature is a prognostic factor of poor outcome in acute stroke. Our aim was to study the relationship between body temperature, HT (haemorrhagic transformation) and biomarkers of BBB (blood-brain barrier) damage in patients with acute ischaemic stroke untreated with rtPA (recombinant tissue-type plasminogen activator). We studied 229 patients with ischaemic stroke <12 h from symptom onset. Body temperature was determined at admission and every 6 h during the first 3 days. HT was evaluated according to ECASS II (second European Co-operative Acute Stroke Study) criteria in a multimodal MRI (magnetic resonance imaging) at 72 h. We found that 55 patients (34.1%) showed HT. HT was associated with cardioembolic stroke (64.2% against 23.0%; P<0.0001), higher body temperature during the first 24 h (36.9°C compared with 36.5°C; P<0.0001), more severe stroke [NIHSS (National Institutes of Health Stroke Scale) score, 14 (9-20) against 10 (7-15); P=0.002], and greater DWI (diffusion-weighted imaging) lesion volume at admission (23.2 cc compared with 13.2 cc; P<0.0001). Plasma MMP-9 (matrix metalloproteinase 9) (187.3 ng/ml compared with 44.2 ng/ml; P<0.0001) and cFn (cellular fibronectin) levels (16.3 μg/ml compared with 7.1 μg/ml; P=0.001) were higher in patients with HT. Body temperature within the first 24 h was independently associated with HT {OR (odds ratio), 7.3 [95% CI (confidence interval), 2.4-22.6]; P<0.0001} after adjustment for cardioembolic stroke subtype, baseline NIHSS score and DWI lesion volume. This effect remained unchanged after controlling for MMP-9 and cFn. In conclusion, high body temperature within the first 24 h after ischaemic stroke is a risk factor for HT in patients untreated with rtPA. This effect is independent of some biological signatures of BBB damage.

Abrogated Freud-1/Cc2d1a Repression of 5-HT1A Autoreceptors Induces Fluoxetine-Resistant Anxiety/Depression-Like Behavior.

PubMed

Vahid-Ansari, Faranak; Daigle, Mireille; Manzini, M Chiara; Tanaka, Kenji F; Hen, René; Geddes, Sean D; Béïque, Jean-Claude; James, Jonathan; Merali, Zul; Albert, Paul R

2017-12-06

Freud-1/Cc2d1a represses the gene transcription of serotonin-1A (5-HT1A) autoreceptors, which negatively regulate 5-HT tone. To test the role of Freud-1 in vivo , we generated mice with adulthood conditional knock-out of Freud-1 in 5-HT neurons ( cF1ko ). In cF1ko mice, 5-HT1A autoreceptor protein, binding and hypothermia response were increased, with reduced 5-HT content and neuronal activity in the dorsal raphe. The cF1ko mice displayed increased anxiety- and depression-like behavior that was resistant to chronic antidepressant (fluoxetine) treatment. Using conditional Freud-1/5-HT1A double knock-out ( cF1/1A dko ) to disrupt both Freud-1 and 5-HT1A genes in 5-HT neurons, no increase in anxiety- or depression-like behavior was seen upon knock-out of Freud-1 on the 5-HT1A autoreceptor-negative background; rather, a reduction in depression-like behavior emerged. These studies implicate transcriptional dysregulation of 5-HT1A autoreceptors by the repressor Freud-1 in anxiety and depression and provide a clinically relevant genetic model of antidepressant resistance. Targeting specific transcription factors, such as Freud-1, to restore transcriptional balance may augment response to antidepressant treatment. SIGNIFICANCE STATEMENT Altered regulation of the 5-HT1A autoreceptor has been implicated in human anxiety, major depression, suicide, and resistance to antidepressants. This study uniquely identifies a single transcription factor, Freud-1, as crucial for 5-HT1A autoreceptor expression in vivo Disruption of Freud-1 in serotonin neurons in mice links upregulation of 5-HT1A autoreceptors to anxiety/depression-like behavior and provides a new model of antidepressant resistance. Treatment strategies to reestablish transcriptional regulation of 5-HT1A autoreceptors could provide a more robust and sustained antidepressant response. Copyright © 2017 the authors 0270-6474/17/3711967-12$15.00/0.

HSV-Mediated Transgene Expression of Chimeric Constructs to Study Behavioral Function of GPCR Heteromers in Mice.

PubMed

Holloway, Terrell; Moreno, Jose L; González-Maeso, Javier

2016-07-09

The heteromeric receptor complex between 5-HT2A and mGlu2 has been implicated in some of the behavioral phenotypes in mouse models of psychosis(1,2). Consequently, investigation of structural details of the interaction between 5-HT2A and mGlu2 affecting schizophrenia-related behaviors represents a powerful translational tool. As previously shown, the head-twitch response (HTR) in mice is elicited by hallucinogenic drugs and this behavioral response is absent in 5-HT2A knockout (KO) mice(3,4). Additionally, by conditionally expressing the 5-HT2A receptor only in cortex, it was demonstrated that 5-HT2A receptor-dependent signaling pathways on cortical pyramidal neurons are sufficient to elicit head-twitch behavior in response to hallucinogenic drugs(3). Finally, it has been shown that the head-twitch behavioral response induced by the hallucinogens DOI and lysergic acid diethylamide (LSD) is significantly decreased in mGlu2-KO mice(5). These findings suggest that mGlu2 is at least in part necessary for the 5-HT2A receptor-dependent psychosis-like behavioral effects induced by LSD-like drugs. However, this does not provide evidence as to whether the 5-HT2A-mGlu2 receptor complex is necessary for this behavioral phenotype. To address this question, herpes simplex virus (HSV) constructs to express either mGlu2 or mGlu2ΔTM4N (mGlu2/mGlu3 chimeric construct that does not form the 5-HT2A-mGlu2 receptor complex) in the frontal cortex of mGlu2-KO mice were used to examine whether this GPCR heteromeric complex is needed for the behavioral effects induced by LSD-like drugs(6).

Serotonin neurones have anti-convulsant effects and reduce seizure-induced mortality

PubMed Central

Buchanan, Gordon F; Murray, Nicholas M; Hajek, Michael A; Richerson, George B

2014-01-01

Sudden unexpected death in epilepsy (SUDEP) is the leading cause of death in patients with refractory epilepsy. Defects in central control of breathing are important contributors to the pathophysiology of SUDEP, and serotonin (5-HT) system dysfunction may be involved. Here we examined the effect of 5-HT neurone elimination or 5-HT reduction on seizure risk and seizure-induced mortality. Adult Lmx1bf/f/p mice, which lack >99% of 5-HT neurones in the CNS, and littermate controls (Lmx1bf/f) were subjected to acute seizure induction by maximal electroshock (MES) or pilocarpine, variably including electroencephalography, electrocardiography, plethysmography, mechanical ventilation or pharmacological therapy. Lmx1bf/f/p mice had a lower seizure threshold and increased seizure-induced mortality. Breathing ceased during most seizures without recovery, whereas cardiac activity persisted for up to 9 min before terminal arrest. The mortality rate of mice of both genotypes was reduced by mechanical ventilation during the seizure or 5-HT2A receptor agonist pretreatment. The selective serotonin reuptake inhibitor citalopram reduced mortality of Lmx1bf/f but not of Lmx1bf/f/p mice. In C57BL/6N mice, reduction of 5-HT synthesis with para-chlorophenylalanine increased MES-induced seizure severity but not mortality. We conclude that 5-HT neurones raise seizure threshold and decrease seizure-related mortality. Death ensued from respiratory failure, followed by terminal asystole. Given that SUDEP often occurs in association with generalised seizures, some mechanisms causing death in our model might be shared with those leading to SUDEP. This model may help determine the relationship between seizures, 5-HT system dysfunction, breathing and death, which may lead to novel ways to prevent SUDEP. PMID:25107926

[Correlation of insulin-like growth factor-1 (IGF-1) to angiogenesis of breast cancer in IGF-1-deficient mice].

PubMed

Tang, Hong-Bo; Ren, Yu-Ping; Zhang, Jun; Ma, Shi-Hui; Gao, Feng; Wu, Yi-Ping

2007-11-01

Insulin-like growth factors (IGFs) play important roles in the development and progression of tumors. But the mechanism of tumorigenesis in relation to IGF-1 is unclear yet. This study was to explore the correlation of circulating IGF-1 level to the angiogenesis of breast cancer in IGF-1-deficient mice. The liver-specific IGF-1-deficient (LID) mice and control mice were injected with 7,12-dimethybenz(a)anthracene (DMBA) to develop breast cancer. Ginsenoside Rg3 was used to intervene tumor growth. The occurrence rates of breast cancer were compared. The expression of vascular endothelial growth factor (VEGF) and microvessel density (MVD) was detected by immunohistochemistry. The occurrence rate of breast cancer was 66.67% in untreated control mice, 33.33% in untreated LID mice, 36.00% in Rg3-treated control mice, and 12.00% in Rg3-treated LID mice. The tumor size was (0.79+/-0.20) cm in untreated control mice, (0.37+/-0.08) cm in untreated LID mice, (0.32+/-0.08) cm in Rg3-treated control mice, and (0.15+/-0.05) cm in Rg3-treated LID mice. The average light density and positive rate of VEGF were the highest in untreated control mice (0.34+/-0.10 and 0.04+/-0.02, P<0.05), and the lowest in Rg3-treated LID mice (0.13+/-0.03 and 0.01+/-0.00, P<0.05). The MVD was 31.9+/-5.3 in untreated control mice, 26.8+/-4.9 in untreated LID mice, 20.1+/-4.9 in Rg3-treated control mice, and 14.4+/-4.9 in Rg3-treated LID mice. Circulating IGF-1 plays a role in the onset and development of breast cancer. Degrading serum IGF-1 level could inhibit angiogenesis and growth of breast cancer. Rg3 could promote this effect.

Dynamic alterations of serotonergic metabolism and receptors during social isolation of low- and high-active mice.

PubMed

Rilke, O; Freier, D; Jähkel, M; Oehler, J

1998-04-01

Alterations induced by social isolation (1 day to 18 weeks) in low- and high-active mice (LAM and HAM) were studied in respect to serotonin metabolism, [3H]-8-OH-DPAT binding of presynaptic (midbrain), postsynaptic (hippocampus) 5-HT1A receptors and [3H]-ketanserin binding of cortical 5-HT2A receptors. Individual housing of mice was associated with reduction of serotonin metabolism, depending on isolation time and brain structure. Whereas a transient decrease in the striatum and cortex was detected between 1 week and 6 weeks, reduction of cerebellar and hippocampal serotonin metabolism was found later (12-18 weeks). Serotonergic systems of HAM were found to be more reactive to environmental disturbances, and their serotonin metabolism was more affected by social isolation. Isolation-induced upregulation of cortical 5-HT2A receptors was measured only in HAM. Densities of postsynaptic 5-HT1A receptors in the hippocampus did differ either in grouped or isolated mice. However, there were significant differences in hippocampal 5-HT1A receptor affinity, especially between 1 day and 3 weeks. Transient downregulation of presynaptic 5-HT1A receptors in the midbrain was found in isolated mice between 3 and 6 weeks. These results are discussed in terms of interactions between serotonergic alterations and isolation-induced aggression.

The effect of chronic fluoxetine on social isolation-induced changes on sucrose consumption, immobility behavior, and on serotonin and dopamine function in hippocampus and ventral striatum.

PubMed

Brenes, Juan C; Fornaguera, Jaime

2009-03-02

This study examined the effect of fluoxetine, a selective serotonin (5-HT) reuptake inhibitor, on isolation-induced changes on sucrose consumption and preference, spontaneous open-field activity, forced swimming behavior, and on tissue levels of 5-HT and dopamine (DA) in hippocampus and ventral striatum (VS). Male Sprague-Dawley rats were reared in social isolation or group housing from postnatal day 28. Thirty-two days later, half of the isolated animals were orally treated with fluoxetine (10mg/kg/day) during the following 34 days. At the end of this period, behavior was assessed and afterward ex-vivo tissue samples were obtained. It was found that fluoxetine restored isolation-increased sucrose consumption and immobility behavior, without affecting locomotor activity, which appeared slightly increased in isolated groups both treated and untreated. In the hippocampus, isolation rearing depleted 5-HT contents and increased 3,4-dihydroxyphenylacetic acid (DOPAC) levels, as well as 5-HT and DA turnover. These neurochemical alterations were reversed by fluoxetine. In VS, treated and untreated isolated rats showed higher 5-HT levels than grouped congeners. Although fluoxetine did not affect 5-HT and DA contents in this region, it slightly reversed the alterations in the 5-HT and DA turnover observed in isolated rats. Overall, social isolation impaired incentive and escape motivated behaviors. At the neurochemical level, isolation rearing affected 5-HT rather than DA activity, and this differential effect was more noticeable in hippocampus than in VS. The chronic treatment with fluoxetine during the last month of rearing somewhat prevented these behavioral and neurochemical alterations. Our data suggest that isolation rearing is an appropriate procedure to model some developmental-related alterations underlying depression disorders.

Cocaine Modulates Mammalian Circadian Clock Timing by Decreasing Serotonin Transport in the SCN

PubMed Central

Prosser, Rebecca A.; Stowie, Adam; Amicarelli, Mario; Nackenoff, Alex G.; Blakely, Randy D.; Glass, J. David

2014-01-01

Cocaine abuse disrupts reward and homeostatic processes through diverse processes, including those involved in circadian clock regulation. Recently we showed that cocaine administration to mice disrupts nocturnal photic phase resetting of the suprachiasmatic (SCN) circadian clock, whereas administration during the day induces non-photic phase shifts. Importantly, the same effects are seen when cocaine is applied to the SCN in vitro, where it blocks photic-like (glutamate-induced) phase shifts at night and induces phase advances during the day. Furthermore, our previous data suggest that cocaine acts in the SCN by enhancing serotonin (5-HT) signaling. For example, the in vitro actions of cocaine mimic those of 5-HT and are blocked by the 5-HT antagonist, metergoline, but not the dopamine receptor antagonist, fluphenazine. Although our data are consistent with cocaine acting through enhance 5-HT signaling, the nonselective actions of cocaine as an antagonist of monoamine transporters raises the question of whether inhibition of the 5-HT transporter (SERT) is key to its circadian effects. Here we investigate this issue using transgenic mice expressing a SERT that exhibits normal 5-HT recognition and transport but significantly reduced cocaine potency (SERT Met172). Circadian patterns of SCN behavioral and neuronal activity did not differ between WT and SERT Met172 mice, nor did they differ in the ability of the 5-HT1A,2,7 receptor agonist, 8-OH-DPAT to reset SCN clock phase, consistent with the normal SERT expression and activity in the transgenic mice. However, 1) cocaine administration does not induce phase advances when administered in vivo or in vitro in SERT Met172 mice; 2) cocaine does not block photic or glutamate-induced (phase shifts in SERT Met172 mice; and 3) cocaine does not induce long-term changes in free-running period in SERT Met172 mice. We conclude that SERT antagonism is required for the phase shifting of the SCN circadian clock induced by cocaine. PMID:24950119

Antidepressant potential of novel flavonoids derivatives from sweet violet (Viola odorata L): Pharmacological, biochemical and computational evidences for possible involvement of serotonergic mechanism.

PubMed

Karim, Nasiara; Khan, Imran; Abdelhalim, Abeer; Khan, Ajmal; Halim, Sobia Ahsan

2018-05-22

Plant-derived natural constituents are of great interest in modern drug discovery due to their natural diversity. Viola odorata L has been traditionally used for the treatment of neuropsychiatric disorders. The present study was undertaken to isolate phytoconstituents including three flavonoids 5,7-Dihydroxy-3,6-dimethoxyflavone[1] 5,7,4'-trihydroxy-3',5'dimethoxyflavone [2] and 5,7,4'-trihydroxy-3'-methoxyflavone [3] from the whole plant of Viola odorata L and to investigate the antidepressant-like effects of these compounds and their possible mechanism of action using antagonists of the serotonergic, dopaminergic and adrenergic system. Classical animal models of depression including tail suspension test (TST) and forced swimming test (FST) using mice were used to evaluate the antidepressant-like effects. Mice were divided into various groups and were administered with either vehicle control, fluoxetine (FLX), or test compounds 1-3 intraperitoneally (i.p.). For experiments involving mechanism determination, mice were pretreated with 5-HT, dopamine and adrenergic antagonists. The brain 5-HT levels were determined following FST. Molecular docking studies were carried out to determine the binding affinity of compounds 1-3 to serotonergic receptors. The results indicated that compounds 1-3 at the dose of 1-30 mg/kg, i.p significantly decreased the immobility time in the FST and TST in mice. The reduction in immobility time was reversed by pre-treating the mice with pCPA (5-HT synthesis inhibitor) 100 mg/kg, i.p. and 5-HT receptor antagonists including WAY100635 (5-HT1a antagonist), ketanserin (a 5-HT2a antagonist) and ondansetron (5-HT3 antagonist) but not with prazosin (α1-adrenergic antagonist) and SCH23390 (D1 dopaminergic antagonist) or haloperidol (D2 dopaminergic antagonist). Moreover, in neurochemical assays, compounds 1-3 caused a significant increase in the 5-HT level in the brain tissue as compared to vehicle. These increases were reversed in the mice groups pretreated with pCPA. Furthermore, molecular docking results also depict that compounds 1-3 can interact with 5HT1A, 5HT2A, and 5HT3 receptors, and are more specific to the 5HT3 receptor subtype. In conclusion, the findings of this study clearly suggest that compounds 1-3 possess antidepressant-like effects which might be mediated via the serotonergic system. Copyright © 2018 Elsevier B.V. All rights reserved.

Increasing brain serotonin corrects CO2 chemosensitivity in methyl-CpG-binding protein 2 (Mecp2)-deficient mice

PubMed Central

Toward, Marie A.; Abdala, Ana P.; Knopp, Sharon J.; Paton, Julian F. R.; Bissonnette, John M.

2013-01-01

Mice deficient in the transcription factor methyl-CpG-binding protein 2 (Mecp2), a mouse model of Rett syndrome, display reduced CO2 chemosensitivity, which may contribute to their breathing abnormalities. In addition, patients with Rett syndrome and male mice that are null for Mecp2 show reduced levels of brain serotonin (5-HT). Serotonin is known to play a role in central chemosensitivity, and we hypothesized that increasing the availability of 5-HT in this mouse model would improve their respiratory response to CO2. Here we determined the apnoeic threshold in heterozygous Mecp2-deficient female mice and examined the effects of blocking 5-HT reuptake on the CO2 response in Mecp2-null male mice. Studies were performed in B6.129P2(C)-Mecp2τm1.1Bird null males and heterozygous females. In an in situ preparation, seven of eight Mecp2-deficient heterozygous females showed arrest of phrenic nerve activity when arterial CO2 was lowered to 3%, whereas the wild-types maintained phrenic nerve amplitude at 53 ± 3% of maximal. In vivo plethysmography studies were used to determine CO2 chemosensitivity in null males. These mice were exposed sequentially to 1, 3 and 5% CO2. The percentage increase in minute ventilation in response to increased inspired CO2 was less in Mecp2−/y than in Mecp2+/y mice. Pretreatment with citalopram, a selective 5-HT reuptake inhibitor (2.5 mg kg−1 I.P.), 40 min prior to CO2 exposure, in Mecp2−/y mice resulted in an improvement in CO2 chemosensitivity to wild-type levels. These results suggest that decreased 5-HT in Mecp2-deficient mice reduces CO2 chemosensitivity, and restoring 5-HT levels can reverse this effect. PMID:23180809

Serotonin 5-HT2C receptor-independent expression of hypothalamic NOR1, a novel modulator of food intake and energy balance, in mice

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nonogaki, Katsunori, E-mail: knonogaki-tky@umin.ac.jp; Department of Lifestyle Medicine, Biomedical Engineering Center, Tohoku University; Kaji, Takao

2009-08-21

NOR1, Nur77 and Nurr1 are orphan nuclear receptors and members of the NR4A subfamily. Here, we report that the expression of hypothalamic NOR1 was remarkably decreased in mildly obese {beta}-endorphin-deficient mice and obese db/db mice with the leptin receptor mutation, compared with age-matched wild-type mice, whereas there were no genotypic differences in the expression of hypothalamic Nur77 or Nurr1 in these animals. The injection of NOR1 siRNA oligonucleotide into the third cerebral ventricle significantly suppressed food intake and body weight in mice. On the other hand, the decreases in hypothalamic NOR1 expression were not found in non-obese 5-HT2C receptor-deficient mice.more » Moreover, systemic administration of m-chlorophenylpiperazine (mCPP), a 5-HT2C/1B receptor agonist, had no effect on hypothalamic NOR1 expression, while suppressing food intake in {beta}-endorphin-deficient mice. These findings suggest that 5-HT2C receptor-independent proopiomelanocortin-derived peptides regulate the expression of hypothalamic NOR1, which is a novel modulator of feeding behavior and energy balance.« less

5-HT2A receptor activation is necessary for CO2-induced arousal

PubMed Central

Smith, Haleigh R.; MacAskill, Amanda; Richerson, George B.

2015-01-01

Hypercapnia-induced arousal from sleep is an important protective mechanism pertinent to a number of diseases. Most notably among these are the sudden infant death syndrome, obstructive sleep apnea and sudden unexpected death in epilepsy. Serotonin (5-HT) plays a significant role in hypercapnia-induced arousal. The mechanism of 5-HT's role in this protective response is unknown. Here we sought to identify the specific 5-HT receptor subtype(s) involved in this response. Wild-type mice were pretreated with antagonists against 5-HT receptor subtypes, as well as antagonists against adrenergic, cholinergic, histaminergic, dopaminergic, and orexinergic receptors before challenge with inspired CO2 or hypoxia. Antagonists of 5-HT2A receptors dose-dependently blocked CO2-induced arousal. The 5-HT2C receptor antagonist, RS-102221, and the 5-HT1A receptor agonist, 8-OH-DPAT, attenuated but did not completely block CO2-induced arousal. Blockade of non-5-HT receptors did not affect CO2-induced arousal. None of these drugs had any effect on hypoxia-induced arousal. 5-HT2 receptor agonists were given to mice in which 5-HT neurons had been genetically eliminated during embryonic life (Lmx1bf/f/p) and which are known to lack CO2-induced arousal. Application of agonists to 5-HT2A, but not 5-HT2C, receptors, dose-dependently restored CO2-induced arousal in these mice. These data identify the 5-HT2A receptor as an important mediator of CO2-induced arousal and suggest that, while 5-HT neurons can be independently activated to drive CO2-induced arousal, in the absence of 5-HT neurons and endogenous 5-HT, 5-HT receptor activation can act in a permissive fashion to facilitate CO2-induced arousal via another as yet unidentified chemosensor system. PMID:25925320

Fluvoxamine moderates reduced voluntary activity following chronic dexamethasone infusion in mice via recovery of BDNF signal cascades.

PubMed

Terada, Kazuki; Izumo, Nobuo; Suzuki, Biora; Karube, Yoshiharu; Morikawa, Tomomi; Ishibashi, Yukiko; Kameyama, Toshiki; Chiba, Koji; Sasaki, Noriko; Iwata, Keiko; Matsuzaki, Hideo; Manabe, Takayuki

2014-04-01

Major depression is a complex disorder characterized by genetic and environmental interactions. Selective serotonin reuptake inhibitors (SSRIs) effectively treat depression. Neurogenesis following chronic antidepressant treatment activates brain derived neurotrophic factor (BDNF) signaling. In this study, we analyzed the effects of the SSRI fluvoxamine (Flu) on locomotor activity and forced-swim behavior using chronic dexamethasone (cDEX) infusions in mice, which engenders depression-like behavior. Infusion of cDEX decreased body weight and produced a trend towards lower locomotor activity during darkness. In the forced-swim test, cDEX-mice exhibited increased immobility times compared with mice administered saline. Flu treatment reversed decreased locomotor activity and mitigated forced-swim test immobility. Real-time polymerase chain reactions using brain RNA samples yielded significantly lower BDNF mRNA levels in cDEX-mice compared with the saline group. Endoplasmic reticulum stress-associated X-box binding protein-1 (XBP1) gene expression was lower in cDEX-mice compared with the saline group. However, marked expression of the XBP1 gene was observed in cDEX-mice treated with Flu compared with mice given saline and untreated cDEX-mice. Expression of 5-HT2A and Sigma-1 receptors decreased after cDEX infusion compared with the saline group, and these decreases normalized to control levels upon Flu treatment. Our results indicate that the Flu moderates reductions in voluntary activity following chronic dexamethasone infusions in mice via recovery of BDNF signal cascades. Copyright © 2014 Elsevier Ltd. All rights reserved.

Adult AMPA GLUA1 receptor subunit loss in 5-HT neurons results in a specific anxiety-phenotype with evidence for dysregulation of 5-HT neuronal activity.

PubMed

Weber, Tillmann; Vogt, Miriam A; Gartside, Sarah E; Berger, Stefan M; Lujan, Rafael; Lau, Thorsten; Herrmann, Elke; Sprengel, Rolf; Bartsch, Dusan; Gass, Peter

2015-05-01

Both the glutamatergic and serotonergic (5-HT) systems are implicated in the modulation of mood and anxiety. Descending cortical glutamatergic neurons regulate 5-HT neuronal activity in the midbrain raphe nuclei through α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and N-methyl-D-aspartate (NMDA) receptors. To analyze the functional role of GLUA1-containing AMPA receptors in serotonergic neurons, we used the Cre-ERT2/loxP-system for the conditional inactivation of the GLUA1-encoding Gria1 gene selectively in 5-HT neurons of adult mice. These Gria1(5-HT-/-) mice exhibited a distinct anxiety phenotype but showed no alterations in locomotion, depression-like behavior, or learning and memory. Increased anxiety-related behavior was associated with significant decreases in tryptophan hydroxylase 2 (TPH2) expression and activity, and subsequent reductions in tissue levels of 5-HT, its metabolite 5-hydroxyindoleacetic acid (5-HIAA), and norepinephrine in the raphe nuclei. However, TPH2 expression and activity as well as monoamine levels were unchanged in the projection areas of 5-HT neurons. Extracellular electrophysiological recordings of 5-HT neurons revealed that, while α1-adrenoceptor-mediated excitation was unchanged, excitatory responses to AMPA were enhanced and the 5-HT1A autoreceptor-mediated inhibitory response to 5-HT was attenuated in Gria1(5-HT-/-) mice. Our data show that a loss of GLUA1 protein in 5-HT neurons enhances AMPA receptor function and leads to multiple local molecular and neurochemical changes in the raphe nuclei that dysregulate 5-HT neuronal activity and induce anxiety-like behavior.

The serotonin hallucinogen 5-MeO-DMT alters cortico-thalamic activity in freely moving mice: Regionally-selective involvement of 5-HT1A and 5-HT2A receptors.

PubMed

Riga, Maurizio S; Lladó-Pelfort, Laia; Artigas, Francesc; Celada, Pau

2017-12-06

5-MeO-DMT is a natural hallucinogen acting as serotonin 5-HT 1A /5-HT 2A receptor agonist. Its ability to evoke hallucinations could be used to study the neurobiology of psychotic symptoms and to identify new treatment targets. Moreover, recent studies revealed the therapeutic potential of serotonin hallucinogens in treating mood and anxiety disorders. Our previous results in anesthetized animals show that 5-MeO-DMT alters cortical activity via 5-HT 1A and 5-HT 2A receptors. Here, we examined 5-MeO-DMT effects on oscillatory activity in prefrontal (PFC) and visual (V1) cortices, and in mediodorsal thalamus (MD) of freely-moving wild-type (WT) and 5-HT 2A -R knockout (KO2A) mice. We performed local field potential multi-recordings evaluating the power at different frequency bands and coherence between areas. We also examined the prevention of 5-MeO-DMT effects by the 5-HT 1A -R antagonist WAY-100635. 5-MeO-DMT affected oscillatory activity more in cortical than in thalamic areas. More marked effects were observed in delta power in V1 of KO2A mice. 5-MeO-DMT increased beta band coherence between all examined areas. In KO2A mice, WAY100635 prevented most of 5-MeO-DMT effects on oscillatory activity. The present results indicate that hallucinatory activity of 5-MeO-DMT is likely mediated by simultaneous alteration of prefrontal and visual activities. The prevention of these effects by WAY-100635 in KO2A mice supports the potential usefulness of 5-HT 1A receptor antagonists to treat visual hallucinations. 5-MeO-DMT effects on PFC theta activity and cortico-thalamic coherence may be related to its antidepressant activity. Copyright © 2017. Published by Elsevier Ltd.

Depletion of angiotensin-converting enzyme 2 reduces brain serotonin and impairs the running-induced neurogenic response.

PubMed

Klempin, Friederike; Mosienko, Valentina; Matthes, Susann; Villela, Daniel C; Todiras, Mihail; Penninger, Josef M; Bader, Michael; Santos, Robson A S; Alenina, Natalia

2018-04-20

Physical exercise induces cell proliferation in the adult hippocampus in rodents. Serotonin (5-HT) and angiotensin (Ang) II are important mediators of the pro-mitotic effect of physical activity. Here, we examine precursor cells in the adult brain of mice lacking angiotensin-converting enzyme (ACE) 2, and explore the effect of an acute running stimulus on neurogenesis. ACE2 metabolizes Ang II to Ang-(1-7) and is essential for the intestinal uptake of tryptophan (Trp), the 5-HT precursor. In ACE2-deficient mice, we observed a decrease in brain 5-HT levels and no increase in the number of BrdU-positive cells following exercise. Targeting the Ang II/AT1 axis by blocking the receptor, or experimentally increasing Trp/5-HT levels in the brain of ACE2-deficient mice, did not rescue the running-induced effect. Furthermore, mice lacking the Ang-(1-7) receptor, Mas, presented a normal neurogenic response to exercise. Our results identify ACE2 as a novel factor required for exercise-dependent modulation of adult neurogenesis and essential for 5-HT metabolism.

Differential contributions of serotonin receptors to the behavioral effects of indoleamine hallucinogens in mice

PubMed Central

Halberstadt, Adam L; Koedood, Liselore; Powell, Susan B; Geyer, Mark A

2012-01-01

Psilocin (4-hydroxy-N,N-dimethyltryptamine) is a hallucinogen that acts as an agonist at 5-HT1A, 5-HT2A, and 5-HT2C receptors. Psilocin is the active metabolite of psilocybin, a hallucinogen that is currently being investigated clinically as a potential therapeutic agent. In the present investigation, we used a combination of genetic and pharmacological approaches to identify the serotonin (5-HT) receptor subtypes responsible for mediating the effects of psilocin on head twitch response (HTR) and the behavioral pattern monitor (BPM) in C57BL/6J mice. We also compared the effects of psilocin with those of the putative 5-HT2C receptor-selective agonist 1-methylpsilocin and the hallucinogen and non-selective serotonin receptor agonist 5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT). Psilocin, 1-methylpsilocin, and 5-MeO-DMT induced the HTR, effects that were absent in mice lacking the 5-HT2A receptor gene. When tested in the BPM, psilocin decreased locomotor activity, holepoking, and time spent in the center of the chamber, effects that were blocked by the selective 5-HT1A antagonist WAY-100635 but were not altered by the selective 5-HT2C antagonist SB 242,084 or by 5-HT2A receptor gene deletion. 5-MeO-DMT produced similar effects when tested in the BPM, and the action of 5-MeO-DMT was significantly attenuated by WAY-100635. Psilocin and 5-MeO-DMT also decreased the linearity of locomotor paths, effects that were mediated by 5-HT2C and 5-HT1A receptors, respectively. In contrast to psilocin and 5-MeO-DMT, 1-methylpsilocin (0.6–9.6 mg/kg) was completely inactive in the BPM. These findings confirm that psilocin acts as an agonist at 5-HT1A, 5-HT2A, and 5-HT2C receptors in mice, whereas the behavioral effects of 1-methylpsilocin indicate that this compound is acting at 5-HT2A sites but is inactive at the 5-HT1A receptor. The fact that 1-methylpsilocin displays greater pharmacological selectivity than psilocin indicates that 1-methylpsilocin represents a potentially useful alternative to psilocybin for development as a potential therapeutic agent. PMID:21148021

5-HT1A/1B Receptors as Targets for Optimizing Pigmentary Responses in C57BL/6 Mouse Skin to Stress

PubMed Central

Wu, Hua-Li; Pang, Si-Lin; Liu, Qiong-Zhen; Wang, Qian; Cai, Min-Xuan; Shang, Jing

2014-01-01

Stress has been reported to induce alterations of skin pigmentary response. Acute stress is associated with increased turnover of serotonin (5-hydroxytryptamine; 5-HT) whereas chronic stress causes a decrease. 5-HT receptors have been detected in pigment cells, indicating their role in skin pigmentation. To ascertain the precise role of 5-HT in stress-induced pigmentary responses, C57BL/6 mice were subjected to chronic restraint stress and chronic unpredictable mild stress (CRS and CUMS, two models of chronic stress) for 21 days, finally resulting in abnormal pigmentary responses. Subsequently, stressed mice were characterized by the absence of a black pigment in dorsal coat. The down-regulation of tyrosinase (TYR) and tyrosinase-related proteins (TRP1 and TRP2) expression in stressed skin was accompanied by reduced levels of 5-HT and decreased expression of 5-HT receptor (5-HTR) system. In both murine B16F10 melanoma cells and normal human melanocytes (NHMCs), 5-HT had a stimulatory effect on melanin production, dendricity and migration. When treated with 5-HT in cultured hair follicles (HFs), the increased expression of melanogenesis-related genes and the activation of 5-HT1A, 1B and 7 receptors also occurred. The serum obtained from stressed mice showed significantly decreased tyrosinase activity in NHMCs compared to that from nonstressed mice. The decrease in tyrosinase activity was further augmented in the presence of 5-HTR1A, 1B and 7 antagonists, WAY100635, SB216641 and SB269970. In vivo, stressed mice received 5-HT precursor 5-hydroxy-l-tryptophan (5-HTP), a member of the class of selective serotonin reuptake inhibitors (fluoxetine; FX) and 5-HTR1A/1B agonists (8-OH-DPAT/CP94253), finally contributing to the normalization of pigmentary responses. Taken together, these data strongly suggest that the serotoninergic system plays an important role in the regulation of stress-induced depigmentation, which can be mediated by 5-HT1A/1B receptors. 5-HT and 5-HTR1A/1B may constitute novel targets for therapy of skin hypopigmentation disorders, especially those worsened with stress. PMID:24586946

Activation of 5-HT7 serotonin receptors reverses metabotropic glutamate receptor-mediated synaptic plasticity in wild-type and Fmr1 knockout mice, a model of Fragile X syndrome.

PubMed

Costa, Lara; Spatuzza, Michela; D'Antoni, Simona; Bonaccorso, Carmela M; Trovato, Chiara; Musumeci, Sebastiano A; Leopoldo, Marcello; Lacivita, Enza; Catania, Maria V; Ciranna, Lucia

2012-12-01

Fragile X syndrome (FXS) is a genetic cause of intellectual disability and autism. Fmr1 knockout (Fmr1 KO) mice, an animal model of FXS, exhibit spatial memory impairment and synapse malfunctioning in the hippocampus, with abnormal enhancement of long-term depression mediated by metabotropic glutamate receptors (mGluR-LTD). The neurotransmitter serotonin (5-HT) modulates hippocampal-dependent learning through serotonin 1A (5-HT1A) and serotonin 7 (5-HT7) receptors; the underlying mechanisms are unknown. We used electrophysiology to test the effects of 5-HT on mGluR-LTD in wild-type and Fmr1 KO mice and immunocytochemistry and biotinylation assay to study related changes of 2-amino-3-(5-methyl-3-oxo-1,2-oxazol-4-yl)propanoic acid (AMPA) glutamate receptor surface expression. Application of 5-HT or 8-OH-DPAT (a mixed 5-HT1A/5-HT7 agonist) reversed mGluR-LTD in hippocampal slices. Reversal of mGluR-LTD by 8-OH-DPAT persisted in the presence of the 5-HT1A receptor antagonist WAY-100635, was abolished by SB-269970 (5-HT7 receptor antagonist), and was mimicked by LP-211, a novel selective 5-HT7 receptor agonist. Consistently, 8-OH-DPAT decreased mGluR-mediated reduction of AMPA glutamate receptor 2 (GluR2) subunit surface expression in hippocampal slices and cultured hippocampal neurons, an effect mimicked by LP-211 and blocked by SB-269970. In Fmr1 KO mice, mGluR-LTD was abnormally enhanced; similarly to wild-type, 8-OH-DPAT reversed mGluR-LTD and decreased mGluR-induced reduction of surface AMPA receptors, an effect antagonized by SB-269970. Serotonin 7 receptor activation reverses metabotropic glutamate receptor-induced AMPA receptor internalization and LTD both in wild-type and in Fmr1 KO mice, correcting excessive mGluR-LTD. Therefore, selective activation of 5-HT7 receptors may represent a novel strategy in the therapy of FXS. Copyright © 2012 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

Pharmacological profile of DA-6886, a novel 5-HT4 receptor agonist to accelerate colonic motor activity in mice.

PubMed

Lee, Min Jung; Cho, Kang Hun; Park, Hyun Min; Sung, Hyun Jung; Choi, Sunghak; Im, Weonbin

2014-07-15

DA-6886, the gastrointestinal prokinetic benzamide derivative is a novel 5-HT4 receptor agonist being developed for the treatment of constipation-predominant irritable bowel syndrome (IBS-C). The purpose of this study was to characterize in vitro and in vivo pharmacological profile of DA-6886. We used various receptor binding assay, cAMP accumulation assay, organ bath experiment and colonic transit assay in normal and chemically constipated mice. DA-6886 exhibited high affinity and selectivity to human 5-HT4 receptor splice variants, with mean pKi of 7.1, 7.5, 7.9 for the human 5-HT4a, 5-HT4b and 5-HT4d, respectively. By contrast, DA-6886 did not show significant affinity for several receptors including dopamine D2 receptor, other 5-HT receptors except for 5-HT2B receptor (pKi value of 6.2). The affinity for 5-HT4 receptor was translated into functional agonist activity in Cos-7 cells expressing 5-HT4 receptor splice variants. Furthermore, DA-6886 induced relaxation of the rat oesophagus preparation (pEC50 value of 7.4) in a 5-HT4 receptor antagonist-sensitive manner. The evaluation of DA-6886 in CHO cells expressing hERG channels revealed that it inhibited hERG channel current with an pIC50 value of 4.3, indicating that the compound was 1000-fold more selective for the 5-HT4 receptor over hERG channels. In the normal ICR mice, oral administration of DA-6886 (0.4 and 2mg/kg) resulted in marked stimulation of colonic transit. Furthermore, in the loperamide-induced constipation mouse model, 2mg/kg of DA-6886 significantly improved the delay of colonic transit, similar to 10mg/kg of tegaserod. Taken together, DA-6886 is a highly potent and selective 5-HT4 receptor agonist to accelerate colonic transit in mice, which might be therapeutic agent having a favorable safety profile in the treatment of gastrointestinal motor disorders such as IBS-C and chronic constipation. Copyright © 2014 Elsevier B.V. All rights reserved.

Differential response of nNOS knockout mice to MDMA ("ecstasy")- and methamphetamine-induced psychomotor sensitization and neurotoxicity.

PubMed

Itzhak, Yossef; Anderson, Karen L; Ali, Syed F

2004-10-01

It has been shown that mice deficient in neuronal nitric oxide synthase (nNOS) gene are resistant to cocaine-induced psychomotor sensitization and methamphetamine (METH)-induced dopaminergic neurotoxicity. The present study was undertaken to investigate the hypothesis that nNOS has a major role in dopamine (DA)- but not serotonin (5-hydroxytryptamine; 5-HT)-mediated effects of psychostimulants. The response of nNOS knockout (KO) and wild-type (WT) mice to the psychomotor-stimulating and neurotoxic effects of 3,4-methylenedioxymethamphetamine (MDMA; "Ecstasy") and METH were investigated. Repeated administration of MDMA for 5 days resulted in psychomotor sensitization in both WT and nNOS KO mice, while repeated administration of METH caused psychomotor sensitization in WT but not in KO mice. Sensitization to both MDMA and METH was persistent for 40 days in WT mice, but not in nNOS KO mice. These findings suggest that the induction of psychomotor sensitization to MDMA and METH is NO independent and NO dependent, respectively, while the persistence of sensitization to both drugs is NO dependent. For the neurochemical studies, a high dose of MDMA caused marked depletion of 5-HT in several brain regions of both WT and KO mice, suggesting that the absence of the nNOS gene did not afford protection against MDMA-induced depletion of 5-HT. Striatal dopaminergic neurotoxicity caused by high doses of MDMA and METH in WT mice was partially prevented in KO mice administered with MDMA, but it was fully precluded in KO mice administered with METH. The differential response of nNOS KO mice to the behavioral and neurotoxic effects of MDMA and METH suggests that the nNOS gene is required for the expression and persistence of DA-mediated effects of METH and MDMA, while 5-HT-mediated effects of MDMA (induction of sensitization and 5-HT depletion) are not dependent on nNOS.

Genetic depletion of brain 5HT reveals a common molecular pathway mediating compulsivity and impulsivity.

PubMed

Angoa-Pérez, Mariana; Kane, Michael J; Briggs, Denise I; Sykes, Catherine E; Shah, Mrudang M; Francescutti, Dina M; Rosenberg, David R; Thomas, David M; Kuhn, Donald M

2012-06-01

Neuropsychiatric disorders characterized by behavioral disinhibition, including disorders of compulsivity (e.g. obsessive-compulsive disorder; OCD) and impulse-control (e.g. impulsive aggression), are severe, highly prevalent and chronically disabling. Treatment options for these diseases are extremely limited. The pathophysiological bases of disorders of behavioral disinhibition are poorly understood but it has been suggested that serotonin dysfunction may play a role. Mice lacking the gene encoding brain tryptophan hydroxylase 2 (Tph2-/-), the initial and rate-limiting enzyme in the synthesis of serotonin, were tested in numerous behavioral assays that are well known for their utility in modeling human neuropsychiatric diseases. Mice lacking Tph2 (and brain 5HT) show intense compulsive and impulsive behaviors to include extreme aggression. The impulsivity is motor in form and not cognitive because Tph2-/- mice show normal acquisition and reversal learning on a spatial learning task. Restoration of 5HT levels by treatment of Tph2-/- mice with its immediate precursor 5-hydroxytryptophan attenuated compulsive and impulsive-aggressive behaviors. Surprisingly, in Tph2-/- mice, the lack of 5HT was not associated with anxiety-like behaviors. The results indicate that 5HT mediates behavioral disinhibition in the mammalian brain independent of anxiogenesis. © 2012 The Authors. Journal of Neurochemistry © 2012 International Society for Neurochemistry.

Sensorimotor function is modulated by the serotonin receptor 1d, a novel marker for gamma motor neurons

PubMed Central

Enjin, Anders; Leão, Katarina E.; Mikulovic, Sanja; Le Merre, Pierre; Tourtellotte, Warren G.; Kullander, Klas

2012-01-01

Gamma motor neurons (MNs), the efferent component of the fusimotor system, regulate muscle spindle sensitivity. Muscle spindle sensory feedback is required for proprioception that includes sensing the relative position of neighboring body parts and appropriately adjust the employed strength in a movement. The lack of a single and specific genetic marker has long hampered functional and developmental studies of gamma MNs. Here we show that the serotonin receptor 1d (5-ht1d) is specifically expressed by gamma MNs and proprioceptive sensory neurons. Using mice expressing GFP driven by the 5-ht1d promotor, we performed whole-cell patch-clamp recordings of 5-ht1d∷GFP+ and 5-ht1d∷GFP− motor neurons from young mice. Hierarchal clustering analysis revealed that gamma MNs have distinct electrophysiological properties intermediate to fast-like and slow-like alpha MNs. Moreover, mice lacking 5-ht1d displayed lower monosynaptic reflex amplitudes suggesting a reduced response to sensory stimulation in motor neurons. Interestingly, adult 5-ht1d knockout mice also displayed improved coordination skills on a beam-walking task, implying that reduced activation of MNs by Ia afferents during provoked movement tasks could reduce undesired exaggerated muscle output. In summary, we show that 5-ht1d is a novel marker for gamma MNs and that the 5-ht1d receptor is important for the ability of proprioceptive circuits to receive and relay accurate sensory information in developing and mature spinal cord motor circuits. PMID:22273508

Serotonin-mediated central fatigue underlies increased endurance capacity in mice from lines selectively bred for high voluntary wheel running.

PubMed

Claghorn, Gerald C; Fonseca, Ivana A T; Thompson, Zoe; Barber, Curtis; Garland, Theodore

2016-07-01

Serotonin (5-hydroxytryptamine; 5-HT) is implicated in central fatigue, and 5-HT1A pharmaceuticals are known to influence locomotor endurance in both rodents and humans. We studied the effects of a 5-HT1A agonist and antagonist on both forced and voluntary exercise in the same set of mice. This cohort of mice was taken from 4 replicate lines of mice that have been selectively bred for high levels of voluntary wheel running (HR) as compared with 4 non-selected control (C) lines. HR mice run voluntarily on wheels about 3× as many revolutions per day as compared with C, and have greater endurance during forced treadmill exercise. We hypothesized that drugs targeting serotonin receptors would have differential effects on locomotor behavior of HR and C mice. Subcutaneous injections of a 5-HT1A antagonist (WAY-100,635), a combination of 5-HT1A agonist and a 5-HT1A/1B partial agonist (8-OH-DPAT+pindolol), or physiological saline were given to separate groups of male mice before the start of each of three treadmill trials. The same manipulations were used later during voluntary wheel running on three separate nights. WAY-100,635 decreased treadmill endurance in HR but not C mice (dose by linetype interaction, P=0.0014). 8-OH-DPAT+pindolol affected treadmill endurance (P<0.0001) in a dose-dependent manner, with no dose by linetype interaction. Wheel running was reduced in HR but not C mice at the highest dose of 8-OH-DPAT+pindolol (dose by linetype, P=0.0221), but was not affected by WAY-100,635 treatment. These results provide further evidence that serotonin signaling is an important determinant of performance during both forced and voluntary exercise. Although the elevated wheel running of HR mice does not appear related to alterations in serotonin signaling, their enhanced endurance capacity does. More generally, our results indicate that both forced and voluntary exercise can be affected by an intervention that acts (primarily) centrally. Copyright © 2016 Elsevier Inc. All rights reserved.

C1473G polymorphism in mouse tryptophan hydroxylase-2 gene in the regulation of the reaction to emotional stress.

PubMed

Bazhenova, Ekaterina Y; Bazovkina, Daria V; Kulikova, Elizabeth A; Fursenko, Dariya V; Khotskin, Nikita V; Lichman, Daria V; Kulikov, Alexander V

2017-02-15

Neurotransmitter serotonin (5-HT) is involved in the regulation of stress response. Tryptophan hydroxylase-2 (TPH2) is the key enzyme of serotonin (5-HT) synthesis in the brain. C1473G polymorphism in Tph2 gene is the main factor defining the enzyme activity in the brain of laboratory mice. The effect of interaction between C1473G polymorphism and 30min restriction stress on the behavior in the open field test, c-Fos gene expression and 5-HT metabolism in the brain in adult male of B6-1473C and B6-1473G congenic mouse lines with high and low TPH2 activity was investigated. A significant effect of genotype x stress interaction on c-Fos mRNA in the hypothalamus (F 1,21 =10.66, p<0.001) and midbrain (F 1,21 =9.18, p<0.01) was observed. The stress-induced rise of c-Fos mRNA in these structures is more intensive in B6-1473G than in B6-1473C mice. A marked effect of genotype x stress interaction on 5-HT level in the cortex (F 1,18 =9.38, p<0.01) and 5-HIAA/5-HT turnover rate in the hypothalamus (F 1,18 =9.01, p<0.01) was revealed. The restriction significantly decreased 5-HT level in the cortex (p<0.01) and increased 5-HIAA/5-HT rate (p<0.001) in the hypothalamus in B6-1473C mice, but not in B6-1473G mice. The present result is the first experimental evidence that C1473G polymorphism is involved in the regulation of the reaction to emotional stress in mice. Copyright © 2017 Elsevier B.V. All rights reserved.

Enhanced effects of amphetamine but reduced effects of the hallucinogen, 5-MeO-DMT, on locomotor activity in 5-HT(1A) receptor knockout mice: implications for schizophrenia.

PubMed

van den Buuse, Maarten; Ruimschotel, Emma; Martin, Sally; Risbrough, Victoria B; Halberstadt, Adam L

2011-01-01

Serotonin-1A (5-HT(1A)) receptors may play a role in schizophrenia and the effects of certain antipsychotic drugs. However, the mechanism of interaction of 5-HT(1A) receptors with brain systems involved in schizophrenia, remains unclear. Here we show that 5-HT(1A) receptor knockout mice display enhanced locomotor hyperactivity to acute treatment with amphetamine, a widely used animal model of hyperdopaminergic mechanisms in psychosis. In contrast, the effect of MK-801 on locomotor activity, modeling NMDA receptor hypoactivity, was unchanged in the knockouts. The effect of the hallucinogen 5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT) was markedly reduced in 5-HT(1A) receptor knockout mice. There were no changes in apomorphine-induced disruption of PPI, a model of sensory gating deficits seen in schizophrenia. Similarly, there were no major changes in density of dopamine transporters (DAT) or dopamine D(1) or D(2) receptors which could explain the behavioural changes observed in 5-HT(1A) receptor knockout mice. These results extend our insight into the possible role of these receptors in aspects of schizophrenia. As also suggested by previous studies using agonist and antagonist drugs, 5-HT(1A) receptors may play an important role in hallucinations and to modulate dopaminergic activity in the brain. Copyright © 2011 Elsevier Ltd. All rights reserved.

Effect of 5-hydroxytryptamine on duodenal mucosal bicarbonate secretion in mice.

PubMed

Tuo, Bi-Guang; Isenberg, Jon I

2003-09-01

5-hydroxytryptamine (5-HT) is an important neurotransmitter and intercellular messenger that modulates many gastrointestinal functions. Because little is known about the role of 5-HT in the regulation of duodenal bicarbonate secretion, we examined the role of 5-HT on duodenal bicarbonate secretion and define neural pathways involved in the actions of 5-HT. Duodenal mucosa from National Institutes of Health Swiss mice was stripped of seromuscular layers and mounted in Ussing chambers. The effect of 5-HT on duodenal bicarbonate secretion was determined by the pH stat technique. Acetylcholine (ACh) release from duodenal mucosa was assessed by preincubating the tissue with [(3)H] choline and measuring 5-HT-evoked release of tritium. 5-HT added to the serosal bath markedly stimulated duodenal bicarbonate secretion and short circuit current (Isc) in a dose-dependent manner (10(-7) mol/L to 10(-3) mol/L; P < 0.0001), whereas mucosally added 5-HT was without effect. 5-HT-stimulated bicarbonate secretion was independent of luminal Cl(-). Pretreatment with tetrodotoxin (TTX) (10(-6) mol/L) or atropine (10(-5) mol/L) markedly reduced 5-HT-stimulated duodenal bicarbonate secretion (by 60% and 65%, respectively; P < 0.001) and Isc (by 45% and 27%, respectively; P < 0.001 and P < 0.05). Pretreatment with N(omega)-nitro-l-arginine methyl ester (l-NAME) (10(-3) mol/L), propranolol (10(-5) mol/L), or phentolamine (10(-5) mol/L) did not significantly alter 5-HT-stimulated duodenal mucosal bicarbonate secretion or Isc. 5-HT concentration-dependently evoked ACh release from duodenal mucosal preparations (P < 0.0001). TTX markedly inhibited 5-HT-evoked ACh release (P < 0.001). 5-HT is a potent activator of duodenal mucosal bicarbonate secretion in mice. Duodenal bicarbonate secretion induced by 5-HT in vitro occurs principally via a cholinergic neural pathway.

Serotonin₂A/C receptors mediate the aggressive phenotype of TLX gene knockout mice.

PubMed

Juárez, Pablo; Valdovinos, Maria G; May, Michael E; Lloyd, Blair P; Couppis, Maria H; Kennedy, Craig H

2013-11-01

Deleting the tailless (TLX) gene in mice produces a highly aggressive phenotype yet to be characterized in terms of heterozygous animals or neurotransmitter mechanisms. We sought to establish pharmacological control over aggression and study the role of serotonin (5-HT)(2A/C) receptors in mediating changes in aggression. We analyzed aggression in mice heterozygous (+/-) or homozygous (-/-) for the TLX gene and wild-types (+/+) using a resident-intruder paradigm. No +/+ mice were aggressive, 36% of +/- TLX and 100% of -/- TLX mice showed aggression. Dose-effect functions were established for clozapine (0.1-1.5mg/kg, ip), ketanserin (0.3-1.25 mg/kg, ip), and (±)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane [(±)DOI] (0.5-2.0 mg/kg, ip). Injecting clozapine decreased the frequency and duration of attacks for +/- TLX and -/- TLX mice. Clozapine did not decrease grooming in either +/- TLX or -/- TLX mice but may have increased locomotion for -/- TLX mice. Injecting ketanserin, a 5-HT(2A/C) receptor antagonist, produced differential decreases in frequency and latency to aggression between genotypes and corresponding increases in locomotor behavior. Injecting (±)DOI, a 5-HT(2A/C) receptor agonist, increased the frequency and duration of attacks, decreased the latency to attacks, and decreased locomotion in +/- and -/- TLX mice. Results of the current study suggest aggression displayed by TLX null and heterozygous mice involves 5-HT(2A/C) receptors. Copyright © 2013 Elsevier B.V. All rights reserved.

[The characteristics of the functional activity of the brain serotoninergic system in the manifestation of natural and pathological anxiety in mice: the effect of the genotype].

PubMed

Avgustinovich, D F; Lipina, T V; Alekseenko, O V; Amstislavskaia, T G; Kudriatseva, N N

1998-01-01

Anxiety was estimated in intact male mice of C57BL/6J (C57) and (CBA) and CBA/Lac (CBA) strains and in males of both strains after the repeated experience of social defeats (losers) in 10 daily aggressive confrontations. A plus-maze test for behavior in a novel situation and a partition test for communicative activity were applied. Tryptophan hydroxylase (TPH) activity, 5-hydroxytryptamine (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) levels were measured in the midbrain, hypothalamus, amygdala, hippocampus, and striatum in losers and controls (5 days of individual housing of intact animals). Intact C57 mice which demonstrated active avoidance in the maze had reduced TPH activity in the all studied brain regions compared to the intact CBA mice with passive behavior. The 5-HT catabolism in intact C57 was lower in the midbrain and hypothalamus and higher in amygdala, hippocampus, and striatum than in CBA mice. Chronic social stress led to expressed anxiety revealed by both tests in C57 losers in contrast to CBA ones. This anxiety was accompanied by an increase in 5-HIAA level and 5-HIAA/5-HT ratio in the midbrain as well as by an increase in 5-HT level and decrease in 5-HIAA level and 5-HIAA/5-HT ratio in the hippocampus of C57 losers in comparison with the controls. Flesinoxan (0.5 mg/kg, i.p.), 5-HT1A receptor agonist, changed the communicative behavior of controls but was ineffective in losers. Thus, a decrease in sensitivity of 5-HT1A receptors was suggested in stress-induced anxiety of C57 losers. The less expressed anxiety in CBA losers was associated with less expressed changes in serotonergic metabolism. It is concluded that serotonergic mechanisms of pathological anxiety induced by the long-term social stress and those of natural anxiety in intact mice are different.

Antinociception by systemically-administered acetaminophen (paracetamol) involves spinal serotonin 5-HT7 and adenosine A1 receptors, as well as peripheral adenosine A1 receptors.

PubMed

Liu, Jean; Reid, Allison R; Sawynok, Jana

2013-03-01

Acetaminophen (paracetamol) is a widely used analgesic, but its sites and mechanisms of action remain incompletely understood. Recent studies have separately implicated spinal adenosine A(1) receptors (A(1)Rs) and serotonin 5-HT(7) receptors (5-HT(7)Rs) in the antinociceptive effects of systemically administered acetaminophen. In the present study, we determined whether these two actions are linked by delivering a selective 5-HT(7)R antagonist to the spinal cord of mice and examining nociception using the formalin 2% model. In normal and A(1)R wild type mice, antinociception by systemic (i.p.) acetaminophen 300mg/kg was reduced by intrathecal (i.t.) delivery of the selective 5-HT(7)R antagonist SB269970 3μg. In mice lacking A(1)Rs, i.t. SB269970 did not reverse antinociception by systemic acetaminophen, indicating a link between spinal 5-HT(7)R and A(1)R mechanisms. We also explored potential roles of peripheral A(1)Rs in antinociception by acetaminophen administered both locally and systemically. In normal mice, intraplantar (i.pl.) acetaminophen 200μg produced antinociception in the formalin test, and this was blocked by co-administration of the selective A(1)R antagonist DPCPX 4.5μg. Acetaminophen administered into the contralateral hindpaw had no effect, indicating a local peripheral action. When acetaminophen was administered systemically, its antinociceptive effect was reversed by i.pl. DPCPX in normal mice; this was also observed in A(1)R wild type mice, but not in those lacking A(1)Rs. In summary, we demonstrate a link between spinal 5-HT(7)Rs and A(1)Rs in the spinal cord relevant to antinociception by systemic acetaminophen. Furthermore, we implicate peripheral A(1)Rs in the antinociceptive effects of locally- and systemically-administered acetaminophen. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Enhanced responsiveness to selective serotonin reuptake inhibitors during lactation.

PubMed

Jury, Nicholas J; McCormick, Betsy A; Horseman, Nelson D; Benoit, Stephen C; Gregerson, Karen A

2015-01-01

The physiology of mood regulation in the postpartum is poorly understood despite the fact that postpartum depression (PPD) is a common pathology. Serotonergic mechanisms and their dysfunction are widely presumed to be involved, which has led us to investigate whether lactation induces changes in central or peripheral serotonin (5-HT) systems and related affective behaviors. Brain sections from lactating (day 10 postpartum) and age-matched nulliparous (non-pregnant) C57BL/6J mice were processed for 5-HT immunohistochemistry. The total number of 5-HT immunostained cells and optical density were measured. Lactating mice exhibited lower immunoreactive 5-HT and intensity in the dorsal raphe nucleus when compared with nulliparous controls. Serum 5-HT was quantified from lactating and nulliparous mice using radioimmunoassay. Serum 5-HT concentrations were higher in lactating mice than in nulliparous controls. Affective behavior was assessed in lactating and non-lactating females ten days postpartum, as well as in nulliparous controls using the forced swim test (FST) and marble burying task (MBT). Animals were treated for the preceding five days with a selective serotonin reuptake inhibitor (SSRI, citalopram, 5mg/kg/day) or vehicle. Lactating mice exhibited a lower baseline immobility time during the FST and buried fewer marbles during the MBT as compared to nulliparous controls. Citalopram treatment changed these behaviors in lactating mice with further reductions in immobility during the FST and decreased marble burying. In contrast, the same regimen of citalopram treatment had no effect on these behaviors in either non-lactating postpartum or nulliparous females. Our findings demonstrate changes in both central and peripheral 5-HT systems associated with lactation, independent of pregnancy. They also demonstrate a significant interaction of lactation and responsiveness to SSRI treatment, which has important implications in the treatment of PPD. Although recent evidence has cast doubt on the effectiveness of SSRIs, these results support their therapeutic use in the treatment of PPD.

Enhanced Responsiveness to Selective Serotonin Reuptake Inhibitors during Lactation

PubMed Central

Jury, Nicholas J.; McCormick, Betsy A.; Horseman, Nelson D.; Benoit, Stephen C.; Gregerson, Karen A.

2015-01-01

The physiology of mood regulation in the postpartum is poorly understood despite the fact that postpartum depression (PPD) is a common pathology. Serotonergic mechanisms and their dysfunction are widely presumed to be involved, which has led us to investigate whether lactation induces changes in central or peripheral serotonin (5-HT) systems and related affective behaviors. Brain sections from lactating (day 10 postpartum) and age-matched nulliparous (non-pregnant) C57BL/6J mice were processed for 5-HT immunohistochemistry. The total number of 5-HT immunostained cells and optical density were measured. Lactating mice exhibited lower immunoreactive 5-HT and intensity in the dorsal raphe nucleus when compared with nulliparous controls. Serum 5-HT was quantified from lactating and nulliparous mice using radioimmunoassay. Serum 5-HT concentrations were higher in lactating mice than in nulliparous controls. Affective behavior was assessed in lactating and non-lactating females ten days postpartum, as well as in nulliparous controls using the forced swim test (FST) and marble burying task (MBT). Animals were treated for the preceding five days with a selective serotonin reuptake inhibitor (SSRI, citalopram, 5mg/kg/day) or vehicle. Lactating mice exhibited a lower baseline immobility time during the FST and buried fewer marbles during the MBT as compared to nulliparous controls. Citalopram treatment changed these behaviors in lactating mice with further reductions in immobility during the FST and decreased marble burying. In contrast, the same regimen of citalopram treatment had no effect on these behaviors in either non-lactating postpartum or nulliparous females. Our findings demonstrate changes in both central and peripheral 5-HT systems associated with lactation, independent of pregnancy. They also demonstrate a significant interaction of lactation and responsiveness to SSRI treatment, which has important implications in the treatment of PPD. Although recent evidence has cast doubt on the effectiveness of SSRIs, these results support their therapeutic use in the treatment of PPD. PMID:25689282

Serotonin 2B Receptors in Mesoaccumbens Dopamine Pathway Regulate Cocaine Responses.

PubMed

Doly, Stéphane; Quentin, Emily; Eddine, Raphaël; Tolu, Stefania; Fernandez, Sebastian P; Bertran-Gonzalez, Jesus; Valjent, Emmanuel; Belmer, Arnauld; Viñals, Xavier; Callebert, Jacques; Faure, Philippe; Meye, Frank J; Hervé, Denis; Robledo, Patricia; Mameli, Manuel; Launay, Jean-Marie; Maldonado, Rafael; Maroteaux, Luc

2017-10-25

Addiction is a maladaptive pattern of behavior following repeated use of reinforcing drugs in predisposed individuals, leading to lifelong changes. Common among these changes are alterations of neurons releasing dopamine in the ventral and dorsal territories of the striatum. The serotonin 5-HT 2B receptor has been involved in various behaviors, including impulsivity, response to antidepressants, and response to psychostimulants, pointing toward putative interactions with the dopamine system. Despite these findings, it remains unknown whether 5-HT 2B receptors directly modulate dopaminergic activity and the possible mechanisms involved. To answer these questions, we investigated the contribution of 5-HT 2B receptors to cocaine-dependent behavioral responses. Male mice permanently lacking 5-HT 2B receptors, even restricted to dopamine neurons, developed heightened cocaine-induced locomotor responses. Retrograde tracing combined with single-cell mRNA amplification indicated that 5-HT 2B receptors are expressed by mesolimbic dopamine neurons. In vivo and ex vivo electrophysiological recordings showed that 5-HT 2B -receptor inactivation in dopamine neurons affects their neuronal activity and increases AMPA-mediated over NMDA-mediated excitatory synaptic currents. These changes are associated with lower ventral striatum dopamine activity and blunted cocaine self-administration. These data identify the 5-HT 2B receptor as a pharmacological intermediate and provide mechanistic insight into attenuated dopamine tone following exposure to drugs of abuse. SIGNIFICANCE STATEMENT Here we report that mice lacking 5-HT 2B receptors totally or exclusively in dopamine neurons exhibit heightened cocaine-induced locomotor responses. Despite the sensitized state of these mice, we found that associated changes include lower ventral striatum dopamine activity and lower cocaine operant self-administration. We described the selective expression of 5-HT 2B receptors in a subpopulation of dopamine neurons sending axons to the ventral striatum. Increased bursting in vivo properties of these dopamine neurons and a concomitant increase in AMPA synaptic transmission to ex vivo dopamine neurons were found in mice lacking 5-HT 2B receptors. These data support the idea that the chronic 5-HT 2B -receptor inhibition makes mice behave like animals already exposed to cocaine with higher cocaine-induced locomotion associated with changes in dopamine neuron reactivity. Copyright © 2017 the authors 0270-6474/17/3710373-17$15.00/0.

Mast Cells and Serotonin Synthesis Modulate Chagas Disease in the Colon: Clinical and Experimental Evidence.

PubMed

Kannen, Vinicius; Sakita, Juliana Y; Carneiro, Zumira A; Bader, Michael; Alenina, Natalia; Teixeira, Regina R; de Oliveira, Enio C; Brunaldi, Mariângela O; Gasparotto, Bianca; Sartori, Daniela C; Fernandes, Cleverson R; Silva, João S; Andrade, Marcus V; Silva, Wilson A; Uyemura, Sergio A; Garcia, Sérgio B

2018-06-01

Trypanosoma cruzi (T. cruzi) infects millions of Latin Americans each year and can induce chagasic megacolon. Little is known about how serotonin (5-HT) modulates this condition. Aim We investigated whether 5-HT synthesis alters T. cruzi infection in the colon. Forty-eight paraffin-embedded samples from normal colon and chagasic megacolon were histopathologically analyzed (173/2009). Tryptophan hydroxylase 1 (Tph1) knockout (KO) mice and c-Kit W-sh mice underwent T. cruzi infection together with their wild-type counterparts. Also, mice underwent different drug treatments (16.1.1064.60.3). In both humans and experimental mouse models, the serotonergic system was activated by T. cruzi infection (p < 0.05). While treating Tph1KO mice with 5-HT did not significantly increase parasitemia in the colon (p > 0.05), rescuing its synthesis promoted trypanosomiasis (p < 0.01). T. cruzi-related 5-HT release (p < 0.05) seemed not only to increase inflammatory signaling, but also to enlarge the pericryptal macrophage and mast cell populations (p < 0.01). Knocking out mast cells reduced trypanosomiasis (p < 0.01), although it did not further alter the neuroendocrine cell number and Tph1 expression (p > 0.05). Further experimentation revealed that pharmacologically inhibiting mast cell activity reduced colonic infection (p < 0.01). A similar finding was achieved when 5-HT synthesis was blocked in c-Kit W-sh mice (p > 0.05). However, inhibiting mast cell activity in Tph1KO mice increased colonic trypanosomiasis (p < 0.01). We show that mast cells may modulate the T. cruzi-related increase of 5-HT synthesis in the intestinal colon.

Insomnia Caused by Serotonin Depletion is Due to Hypothermia.

PubMed

Murray, Nicholas M; Buchanan, Gordon F; Richerson, George B

2015-12-01

Serotonin (5-hydroxytryptamine, 5-HT) neurons are now thought to promote wakefulness. Early experiments using the tryptophan hydroxylase inhibitor para-chlorophenylalanine (PCPA) had led to the opposite conclusion, that 5-HT causes sleep, but those studies were subsequently contradicted by electrophysiological and behavioral data. Here we tested the hypothesis that the difference in conclusions was due to failure of early PCPA experiments to control for the recently recognized role of 5-HT in thermoregulation. Adult male C57BL/6N mice were treated with PCPA (800 mg/kg intraperitoneally for 5 d; n = 15) or saline (n = 15), and housed at 20 °C (normal room temperature) or at 33 °C (thermoneutral for mice) for 24 h. In a separate set of experiments, mice were exposed to 4 °C for 4 h to characterize their ability to thermoregulate. PCPA treatment reduced brain 5-HT to less than 12% of that of controls. PCPA-treated mice housed at 20 °C spent significantly more time awake than controls. However, core body temperature decreased from 36.5 °C to 35.1 °C. When housed at 33 °C, body temperature remained normal, and total sleep duration, sleep architecture, and time in each vigilance state were the same as controls. When challenged with 4 °C, PCPA-treated mice experienced a precipitous drop in body temperature, whereas control mice maintained a normal body temperature. These results indicate that early experiments using para-chlorophenylalanine that led to the conclusion that 5-hydroxytryptamine (5-HT) causes sleep were likely confounded by hypothermia. Temperature controls should be considered in experiments using 5-HT depletion. © 2015 Associated Professional Sleep Societies, LLC.

Autism gene variant causes hyperserotonemia, serotonin receptor hypersensitivity, social impairment and repetitive behavior.

PubMed

Veenstra-VanderWeele, Jeremy; Muller, Christopher L; Iwamoto, Hideki; Sauer, Jennifer E; Owens, W Anthony; Shah, Charisma R; Cohen, Jordan; Mannangatti, Padmanabhan; Jessen, Tammy; Thompson, Brent J; Ye, Ran; Kerr, Travis M; Carneiro, Ana M; Crawley, Jacqueline N; Sanders-Bush, Elaine; McMahon, Douglas G; Ramamoorthy, Sammanda; Daws, Lynette C; Sutcliffe, James S; Blakely, Randy D

2012-04-03

Fifty years ago, increased whole-blood serotonin levels, or hyperserotonemia, first linked disrupted 5-HT homeostasis to Autism Spectrum Disorders (ASDs). The 5-HT transporter (SERT) gene (SLC6A4) has been associated with whole blood 5-HT levels and ASD susceptibility. Previously, we identified multiple gain-of-function SERT coding variants in children with ASD. Here we establish that transgenic mice expressing the most common of these variants, SERT Ala56, exhibit elevated, p38 MAPK-dependent transporter phosphorylation, enhanced 5-HT clearance rates and hyperserotonemia. These effects are accompanied by altered basal firing of raphe 5-HT neurons, as well as 5HT(1A) and 5HT(2A) receptor hypersensitivity. Strikingly, SERT Ala56 mice display alterations in social function, communication, and repetitive behavior. Our efforts provide strong support for the hypothesis that altered 5-HT homeostasis can impact risk for ASD traits and provide a model with construct and face validity that can support further analysis of ASD mechanisms and potentially novel treatments.

Strain differences in paroxetine-induced reduction of immobility time in the forced swimming test in mice: role of serotonin.

PubMed

Guzzetti, Sara; Calcagno, Eleonora; Canetta, Alessandro; Sacchetti, Giuseppina; Fracasso, Claudia; Caccia, Silvio; Cervo, Luigi; Invernizzi, Roberto W

2008-10-10

We studied the antidepressant-like effect of paroxetine in strains of mice carrying different isoforms of tryptophan hydroxylase-2 (TPH-2), the enzyme responsible for the synthesis of brain serotonin (5-HT). The effect of paroxetine alone and in combination with pharmacological treatments enhancing or lowering 5-HT synthesis or melatonin was assessed in the forced swimming test in mice carrying allelic variants of TPH-2 (1473C in C57BL/6 and 1473G in DBA/2 and BALB/c). Changes in brain 5-hydroxytryptophan (5-HTP) accumulation and melatonin levels were measured by high-performance liquid chromatography. Paroxetine (2.5 and 5 mg/kg) reduced immobility time in C57BL/6J and C57BL/6N mice but had no such effect in DBA/2J, DBA/2N and BALB/c mice, even at 10 mg/kg. Enhancing 5-HT synthesis with tryptophan reinstated the antidepressant-like effect of paroxetine in DBA/2J, DBA/2N and BALB/c mice whereas inhibition of 5-HT synthesis prevented the effect of paroxetine in C57BL/6N mice. The response to paroxetine was not associated with changes in locomotor activity, brain melatonin or brain levels of the drug measured at the end of the behavioral test. These results support the importance of 5-HT synthesis in the response to SSRIs and suggest that melatonin does not contribute to the ability of tryptophan to rescue the antidepressant-like effect of paroxetine.

5-HT2CRs expressed by pro-opiomelanocortin neurons regulate insulin sensitivity in liver

USDA-ARS?s Scientific Manuscript database

Mice lacking 5-HT 2C receptors displayed hepatic insulin resistance, a phenotype normalized by re-expression of 5-HT2CRs only in pro-opiomelanocortin (POMC) neurons. 5-HT2CR deficiency also abolished the anti-diabetic effects of meta-chlorophenylpiperazine (a 5-HT2CR agonist); these effects were re...

Diphtheria toxin treatment of Pet-1-Cre floxed diphtheria toxin receptor mice disrupts thermoregulation without affecting respiratory chemoreception.

PubMed

Cerpa, V; Gonzalez, A; Richerson, G B

2014-10-24

In genetically-modified Lmx1b(f/f/p) mice, selective deletion of LMX1B in Pet-1 expressing cells leads to failure of embryonic development of serotonin (5-HT) neurons. As adults, these mice have a decreased hypercapnic ventilatory response and abnormal thermoregulation. This mouse model has been valuable in defining the normal role of 5-HT neurons, but it is possible that developmental compensation reduces the severity of observed deficits. Here we studied mice genetically modified to express diphtheria toxin receptors (DTR) on Pet-1 expressing neurons (Pet-1-Cre/floxed DTR or Pet1/DTR mice). These mice developed with a normal complement of 5-HT neurons. As adults, systemic treatment with 2-35μg of diphtheria toxin (DT) reduced the number of tryptophan hydroxylase-immunoreactive (TpOH-ir) neurons in the raphe nuclei and ventrolateral medulla by 80%. There were no effects of DT on minute ventilation (VE) or the ventilatory response to hypercapnia or hypoxia. At an ambient temperature (TA) of 24°C, all Pet1/DTR mice dropped their body temperature (TB) below 35°C after DT treatment, but the latency was shorter in males than females (3.0±0.37 vs. 4.57±0.29days, respectively; p<0.001). One week after DT treatment, mice were challenged by dropping TA from 37°C to 24°C, which caused TB to decrease more in males than in females (29.7±0.31°C vs. 33.0±1.3°C, p<0.01). We conclude that the 20% of 5-HT neurons that remain after DT treatment in Pet1/DTR mice are sufficient to maintain normal baseline breathing and a normal response to CO2, while those affected include some essential for thermoregulation, in males more than females. In comparison to models with deficient embryonic development of 5-HT neurons, acute deletion of 5-HT neurons in adults leads to a greater defect in thermoregulation, suggesting that significant developmental compensation can occur. Copyright © 2014 IBRO. Published by Elsevier Ltd. All rights reserved.

Radiosensitization of HT-29 cells and xenografts by the nitric oxide donor DETANONOate.

PubMed

Gao, Xiaohuan; Saha, Debabrata; Kapur, Payal; Anthony, Thomas; Livingston, Edward H; Huerta, Sergio

2009-08-01

Mechanisms of radioresistance in rectal cancer remain unclear. To determine mechanisms of radioresistance in rectal cancer cells and to assess the role of the nitric oxide donor DETANONOate as a radiosensitizing agent. Survival was determined by clonogenic assays, apoptosis by PARP-1 cleavage, and phenotypic differences by Western blot analysis. SCID mice bearing HT-29 xenografts were treated with ionizing radiation (IR) [2.0 Gy x 5], DETANONOate [0.4 mg/kg i.p.], or combination treatment. Colorectal cancer HT-29-p53-null cells were resistant and HCT-116-p53 wild-type cells sensitive to IR, which correlated with cleaved PARP-1. Increased levels of p21 occurred in HCT-116 cells, while Bcl-2 and survivin were elevated in HT-29 cells. Radiosensitization was achieved with a substantial elevation of cleaved PARP-1 in DETANONOate-HT-29-treated versus control cells, which was accompanied by elevation of p21, p27, and BAX, and a concomitant decrease in Bcl-2. SCID mice bearing HT-29 xenografts demonstrated a 37.6%, 51.1%, and 70.1% inhibition in tumor growth in mice receiving IR, DETANONOate, and combination treatment versus control, respectively. Radioresistant HT-29 cells are p53-null and have substantially decreased levels of p21. DETANONOate radiosensitized HT-29 cells in vitro and in vivo by an additive effect in apoptosis.

Serotonin transporter, 5-HT1A receptor, and behavior in DBA/2J mice in comparison with four inbred mouse strains.

PubMed

Popova, Nina K; Naumenko, Vladimir S; Tibeikina, Marina A; Kulikov, Alexander V

2009-12-01

Prepulse inhibition (PPI), the reduction in acoustic startle produced when it is preceded by a weak prepulse stimulus, is impaired in schizophrenic patients. The DBA/2J mouse strain displayed deficient PPI and is therefore suggested as an experimental animal model for the loss of sensorimotor gating in schizophrenia. Brain serotonin (5-HT) has been implicated in the pathophysiology of several psychiatric disorders, including major depressive disorder and schizophrenia. In the present study, behavior, 5-HT transporter (5-HTT) mRNA level, 5-HT(1A) receptor mRNA level, and 5-HT(1A) receptor density in the brain regions were studied in DBA/2J mice in comparison with four inbred mouse strains (CBA/Lac, C57BL/6, BALB/c, and ICR). A decrease in 5-HTT mRNA level in the midbrain and a reduced density of 5-HT(1A) receptors in the frontal cortex without significant changes in 5-HT(1A) receptor mRNA level in DBA/2J mice were found. It was shown that, along with decreased PPI, DBA/2J mice demonstrated considerably reduced immobility in the tail suspension test and in the forced swim test. No significant interstrain differences in intermale aggression, or in light-dark box and elevated plus-maze tests, were found. The results suggested the involvement of decreased 5-HTT gene expression and 5-HT(1A) receptor density in genetically defined PPI deficiency and showed a lack of any association between PPI deficiency and predisposition to aggressive, anxiety, and depressive-like behaviors. Copyright 2009 Wiley-Liss, Inc.

Monoamine oxidase and head-twitch response in mice. Mechanisms of alpha-methylated substrate derivatives.

PubMed

Nakagawasai, Osamu; Arai, Yuichiro; Satoh, Shin-etsu; Satoh, Nobunori; Neda, Mitsuro; Hozumi, Masato; Oka, Ryusho; Hiraga, Hajime; Tadano, Takeshi

2004-01-01

It is well known that head-twitch response (HTR) in mice represents hallucinations, since administration of lysergic acid diethylamide (LSD) produces hallucinations in humans, and the HTR in mice is induced by administration of LSD as a hallucinogen. The HTR is produced by excitation of 5-hydroxytryptamine (5-HT)2A receptors. In this paper, we review the mechanisms of HTR induced by various drugs such as 5-HT precursor, 5-HT receptor agonist, 5-HT releaser, hallucinogenic compounds, benzodiazepins and cannabinoid. The response induced by HTR-inducers is significantly enhanced by combined treatment with a non-selective form of monoamine oxidase (MAO) inhibitor. Thus, the relationship between MAO activity and HTR caused by these drugs (especially, alpha-methylated analogous compounds which 5-fluoro-alpha-methyltryptamine, 6-fluoro-alpha-methyltryptamine and p-hydroxyamphetamine) is presented in detail.

Effect of sodium-alginate and laminaran on Salmonella Typhimurium infection in human enterocyte-like HT-29-Luc cells and BALB/c mice.

PubMed

Kuda, Takashi; Kosaka, Misa; Hirano, Shino; Kawahara, Miho; Sato, Masahiro; Kaneshima, Tai; Nishizawa, Makoto; Takahashi, Hajime; Kimura, Bon

2015-07-10

Brown algal polysaccharides such as alginate, polymers of uronic acids, and laminaran, beta-1,3 and 1,6-glucan, can be fermented by human intestinal microbiota. To evaluate the effects of these polysaccharides on infections caused by food poisoning pathogens, we investigated the adhesion and invasion of pathogens (Salmonella Typhimurium, Listeria monocytogenes and Vibrio parahaemolyticus) in human enterocyte-like HT-29-Luc cells and in infections caused in BALB/c mice. Both sodium Na-alginate and laminaran (0.1% each) inhibited the adhesion of the pathogens to HT-29-Luc cells by approximately 70-90%. The invasion of S. Typhimurium was also inhibited by approximately 70 and 80% by Na-alginate and laminaran, respectively. We observed that incubation with Na-alginate for 18 h increased the transepithelial electrical resistance of HT-29-Luc monolayer cells. Four days after inoculation with 7 log CFU/mouse of S. Typhimurium, the faecal pathogen count in mice that were not fed polysaccharides (control mice) was about 6.5 log CFU/g while the count in mice that were fed Na-alginate had decreased to 5.0 log CFU/g. The liver pathogen count, which was 4.1 log CFU/g in the control mice, was also decreased in mice that were fed Na-alginate. In contrast, the mice that were fed laminaran exhibited a more severe infection than that exhibited by control mice. Copyright © 2015 Elsevier Ltd. All rights reserved.

Complex discriminative stimulus properties of (+)lysergic acid diethylamide (LSD) in C57Bl/6J mice.

PubMed

Benneyworth, Michael A; Smith, Randy L; Barrett, Robert J; Sanders-Bush, Elaine

2005-06-01

The drug discrimination procedure is the most frequently used in vivo model of hallucinogen activity. Historically, most drug discrimination studies have been conducted in the rat. With the development of genetically modified mice, a powerful new tool has become available for investigating the mechanisms of drug-induced behavior. The current paper is part of an ongoing effort to determine the utility of the drug discrimination technique for evaluating hallucinogenic drugs in mice. To establish the training procedures and characterize the stimulus properties of (+)lysergic acid diethylamide (LSD) in mice. Using a two-lever drug discrimination procedure, C57Bl/6J mice were trained to discriminate 0.45 mg/kg LSD vs saline on a VI30 sec schedule of reinforcement, with vanilla-flavored Ensure serving as the reinforcer. As in rats, acquisition was orderly, but the training dose was nearly five-fold higher for mice than rats. LSD lever selection was dose-dependent. Time-course studies revealed a rapid loss of the LSD stimulus effects. The 5-HT(2A/2C) receptor agonist, 2,5-dimethoxy-4-bromoamphetamine [(-)DOB] (1.0 mg/kg), substituted fully for LSD and the 5-HT(1A) receptor agonist, 8-hydroxy-2-(di-n-propylamino)-tetralin (8-OH-DPAT) (1.6 mg/kg), substituted partially for LSD. Pretreatment with the 5-HT(2A) receptor-selective antagonist, MDL 100907, or the 5-HT(1A)-selective antagonist WAY 100635, showed that each antagonist only partially blocked LSD discrimination. Substitution of 1.0 mg/kg (-)DOB for LSD was fully blocked by pretreatment with MDL 100907 but unaltered by WAY 100635 pretreatment. These data suggest that in mice the stimulus effects of LSD have both a 5-HT(2A) receptor and a 5-HT(1A) receptor component.

Selective effects of 5-HT2C receptor modulation on performance of a novel valence-probe visual discrimination task and probabilistic reversal learning in mice.

PubMed

Phillips, Benjamin U; Dewan, Sigma; Nilsson, Simon R O; Robbins, Trevor W; Heath, Christopher J; Saksida, Lisa M; Bussey, Timothy J; Alsiö, Johan

2018-04-22

Dysregulation of the serotonin (5-HT) system is a pathophysiological component in major depressive disorder (MDD), a condition closely associated with abnormal emotional responsivity to positive and negative feedback. However, the precise mechanism through which 5-HT tone biases feedback responsivity remains unclear. 5-HT2C receptors (5-HT2CRs) are closely linked with aspects of depressive symptomatology, including abnormalities in reinforcement processes and response to stress. Thus, we aimed to determine the impact of 5-HT2CR function on response to feedback in biased reinforcement learning. We used two touchscreen assays designed to assess the impact of positive and negative feedback on probabilistic reinforcement in mice, including a novel valence-probe visual discrimination (VPVD) and a probabilistic reversal learning procedure (PRL). Systemic administration of a 5-HT2CR agonist and antagonist resulted in selective changes in the balance of feedback sensitivity bias on these tasks. Specifically, on VPVD, SB 242084, the 5-HT2CR antagonist, impaired acquisition of a discrimination dependent on appropriate integration of positive and negative feedback. On PRL, SB 242084 at 1 mg/kg resulted in changes in behaviour consistent with reduced sensitivity to positive feedback. In contrast, WAY 163909, the 5-HT2CR agonist, resulted in changes associated with increased sensitivity to positive feedback and decreased sensitivity to negative feedback. These results suggest that 5-HT2CRs tightly regulate feedback sensitivity bias in mice with consequent effects on learning and cognitive flexibility and specify a framework for the influence of 5-HT2CRs on sensitivity to reinforcement.

Decreased Incentive Motivation Following Knockout or Acute Blockade of the Serotonin Transporter: Role of the 5-HT2C Receptor.

PubMed

Browne, Caleb J; Fletcher, Paul J

2016-09-01

Acute pharmacological elevation of serotonin (5-hydroxytryptamine; 5-HT) activity decreases operant responding for primary reinforcers, suggesting that 5-HT reduces incentive motivation. The mechanism by which 5-HT alters incentive motivation is unknown, but parallel evidence that 5-HT2C receptor agonists also reduce responding for primary reinforcers implicates this receptor as a potential candidate. These experiments examined whether chronic and acute disruptions of serotonin transporter (SERT) activity altered incentive motivation, and whether the 5-HT2C receptor mediated the effects of elevated 5-HT on behavior. To assess incentive motivation, we measured responding for three different reinforcers: a primary reinforcer (saccharin), a conditioned reinforcer (CRf), and an unconditioned sensory reinforcer (USRf). In the chronic condition, responding was compared between SERT knockout (SERT-KO) mice and their wild-type littermates. In the acute condition, responding was examined in wild-type mice following treatment with 10 or 20 mg/kg citalopram, or its vehicle. The ability of the selective 5-HT2C antagonist SB 242084 to prevent the effects of SERT-KO and citalopram on responding was subsequently examined. Both SERT-KO and citalopram reduced responding for saccharin, a CRf, and a USRf. Treatment with SB 242084 enhanced responding for a CRf and a USRf in SERT-KO mice and blocked the effects of citalopram on CRf and USRf responding. However, SB 242084 was unable to prevent the effects of SERT-KO or citalopram on responding for saccharin. These results support a powerful inhibitory function for 5-HT in the control of incentive motivation, and indicate that the 5-HT2C receptor mediates these effects of 5-HT in a reinforcer-dependent manner.

Influence of serotonin and melatonin on some parameters of gastrointestinal activity.

PubMed

Bubenik, G A; Dhanvantari, S

1989-01-01

In vitro melatonin (M) reduced the tone of gut muscles and counteracted the tonic effect of serotonin (5-HT). In vivo 0.1 to 4 mg of 5-HT (contained in beeswax implants) decreased the food transit time (FTT) in a dose-dependent manner, but higher doses (5 and 6 mg) increased the FTT. Melatonin injected intraperitoneally into mice bearing 5-HT implants (2 mg per animal) blocked partly the serotonin effect and increased FTT by 50%; however, no dose-dependent effect was observed when doses between 0.01 and 1 mg were used. Surprisingly, M injected into intact mice decreased FTT to levels comparable to those observed in 5-HT implanted, M-treated mice. Again, this significant decrease was not dose-dependent between 0.02 and 1 mg. Although in vitro the maximal inhibition of serotonin-induced spasm was achieved when the M:5-HT ratio was 50-100:1, in vivo the effective ratio was about 1:1. This may indicate that part of M action on the gut movement is mediated by extraintestinal mechanisms. A hypothetical, counterbalancing system of M and 5-HT regulation of gut activity (similar to adrenaline-acetylcholine system) is proposed.

Pharmacological and physiological assessment of serotonin formation and degradation in isolated preparations from mouse and human hearts.

PubMed

Gergs, Ulrich; Jung, Franziska; Buchwalow, Igor B; Hofmann, Britt; Simm, Andreas; Treede, Hendrik; Neumann, Joachim

2017-12-01

Using transgenic (TG) mice that overexpress the human serotonin (5-HT) 4a receptor specifically in cardiomyocytes, we wanted to know whether 5-HT can be formed and degraded in the mammalian heart and whether this can likewise lead to inotropic and chronotropic effects in this TG model. We noted that the 5-HT precursor 5-hydroxy-tryptophan (5-HTP) can exert inotropic and chronotropic effects in cardiac preparations from TG mice but not from wild-type (WT) mice; similar results were found in human atrial preparations as well as in intact TG animals using echocardiography. Moreover, by immunohistochemistry we could detect 5-HT metabolizing enzymes and 5-HT transporters in mouse hearts as well as in human atria. Hence, in the presence of an inhibitor of aromatic l-amino acid decarboxylase, the positive inotropic effects of 5-HTP were absent in TG and isolated human atrial preparations, and, moreover, inhibitors of enzymes involved in 5-HT degradation enhanced the efficacy of 5-HT in TG atria. A releaser of neurotransmitters increased inotropy in the isolated TG atrium, and this effect could be blocked by a 5-HT 4a receptor antagonist. Fluoxetine, an inhibitor of 5-HT uptake, elevated the potency of 5-HT to increase contractility in the TG atrium. In addition, inhibitors of organic cation and monoamine transporters apparently reduced the positive inotropic potency of 5-HT in the TG atrium. Hence, we tentatively conclude that a local production and degradation of 5-HT in the mammalian heart and more specifically in mammalian myocytes probably occurs. Conceivably, this formation of 5-HT and possibly impaired degradation may be clinically relevant in cases of unexplained tachycardia and other arrhythmias. NEW & NOTEWORTHY The present work suggests that inotropically active serotonin (5-HT) can be formed in the mouse and human heart and probably by cardiomyocytes themselves. Moreover, active degradation of 5-HT seems to occur in the mammalian heart. These findings may again increase the interest of researchers for cardiac effects of 5-HT. Copyright © 2017 the American Physiological Society.

Strain-specific genetics, anatomy and function of enteric neural serotonergic pathways in inbred mice

PubMed Central

Neal, Kathleen B; Parry, Laura J; Bornstein, Joel C

2009-01-01

Serotonin (5-HT) powerfully affects small intestinal motility and 5-HT-immunoreactive (IR) neurones are highly conserved between species. 5-HT synthesis in central neurones and gastrointestinal mucosa depends on tissue-specific isoforms of the enzyme tryptophan hydroxylase (TPH). RT-PCR identified strain-specific expression of a polymorphism (1473C/G) of the tph2 gene in longitudinal muscle–myenteric plexus preparations of C57Bl/6 and Balb/c mice. The former expressed the high-activity C allele, the latter the low-activity G allele. Confocal microscopy was used to examine close contacts between 5-HT-IR varicosities and myenteric neurones immunoreactive for neuronal nitric oxide synthase (NOS) or calretinin in these two strains. Significantly more close contacts were identified to NOS- (P < 0.05) and calretinin-IR (P < 0.01) neurones in C57Bl/6 jejunum (NOS 1.6 ± 0.3, n= 52; calretinin 5.2 ± 0.4, n= 54), than Balb/c jejunum (NOS 0.9 ± 0.2, n= 78; calretinin 3.5 ± 0.3, n= 98). Propagating contractile complexes (PCCs) were identified in the isolated jejunum by constructing spatiotemporal maps from video recordings of cannulated segments in vitro. These clusters of contractions usually arose towards the anal end and propagated orally. Regular PCCs were initiated at intraluminal pressures of 6 cmH2O, and abolished by tetrodotoxin (1 μm). Jejunal PCCs from C57Bl/6 mice were suppressed by a combination of granisetron (1 μm, 5-HT3 antagonist) and SB207266 (10 nm, 5-HT4 antagonist), but PCCs from Balb/c mice were unaffected. There were, however, no strain-specific differences in sensitivity of longitudinal muscle contractions to exogenous 5-HT or blockade of 5-HT3 and 5-HT4 receptors. These data associate a genetic difference with significant structural and functional consequences for enteric neural serotonergic pathways in the jejunum. PMID:19064621

Insertion mutation at the C-terminus of the serotonin transporter disrupts brain serotonin function and emotion-related behaviors in mice.

PubMed

Zhao, S; Edwards, J; Carroll, J; Wiedholz, L; Millstein, R A; Jaing, C; Murphy, D L; Lanthorn, T H; Holmes, A

2006-06-19

The 5-hydroxytryptamine transporter (5-HTT) regulates 5-hydroxytryptamine (5-HT) neurotransmission by removing 5-HT from the synaptic cleft. Emerging evidence from clinical and genetic studies implicates the 5-HTT in various neuropsychiatric conditions, including anxiety and depression. Here we report that a 5-HTT null mutant mouse line was generated by gene trapping that disrupted the sequence encoding the C-terminus of 5-HTT. This mutation resulted in significant reduction of 5-HTT mRNA and loss of 5-HTT protein. Brain levels of 5-HT and its major metabolite, 5-hydroxyindoleacetic acid, were markedly decreased in C-terminus 5-HTT -/- mice, while 5-HT uptake or 5-HT content in platelets was absent. Behavioral phenotyping showed that C-terminus 5-HTT -/- mice were normal on a screen for gross behavioral, neurological, and sensory functions. In the tail suspension test for depression-related behavior, C-terminus 5-HTT -/- mice showed increased immobility relative to their +/+ controls. By comparison, a previously generated line of 5-HTT -/- mice lacking exon 2, encoding the N-terminus of the 5-HTT, showed abnormally high immobility in response to repeated, but not acute, exposure to the tail suspension test. In a novel, brightly-lit open field, both C-terminus 5-HTT -/- mice and N-terminus 5-HTT -/- mice displayed decreased center time and reduced locomotor activity compared with their +/+ controls. Both mutant lines buried significantly fewer marbles than their +/+ controls in the marble burying test. These findings further demonstrate the neurobiological functions of the 5-HTT and add to a growing literature linking genetic variation in 5-HTT function with emotional abnormalities.

The effects of serotonin1A receptor on female mice body weight and food intake are associated with the differential expression of hypothalamic neuropeptides and the GABAA receptor.

PubMed

Butt, Isma; Hong, Andrew; Di, Jing; Aracena, Sonia; Banerjee, Probal; Shen, Chang-Hui

2014-10-01

Both common eating disorders anorexia nervosa and bulimia nervosa are characteristically diseases of women. To characterize the role of the 5-HT1A receptor (5-HT1A-R) in these eating disorders in females, we investigated the effect of saline or 8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT) treatment on feeding behavior and body weight in adult WT female mice and in adult 5-HT1A-R knockout (KO) female mice. Our results showed that KO female mice have lower food intake and body weight than WT female mice. Administration of 8-OH-DPAT decreased food intake but not body weight in WT female mice. Furthermore, qRT-PCR was employed to analyze the expression levels of neuropeptides, γ-aminobutyric acid A receptor subunit β (GABAA β subunits) and glutamic acid decarboxylase in the hypothalamic area. The results showed the difference in food intake between WT and KO mice was accompanied by differential expression of POMC, CART and GABAA β2, and the difference in body weight between WT and KO mice was associated with significantly different expression levels of CART and GABAA β2. As such, our data provide new insight into the role of 5-HT1A-R in both feeding behavior and the associated expression of neuropeptides and the GABAA receptor. Copyright © 2014 Elsevier Ltd. All rights reserved.

5-HT2A Receptor Binding in the Frontal Cortex of Parkinson's Disease Patients and Alpha-Synuclein Overexpressing Mice: A Postmortem Study

PubMed Central

Rasmussen, Nadja Bredo; Olesen, Mikkel Vestergaard; Plenge, Per; Klein, Anders Bue; Westin, Jenny E.; Fog, Karina

2016-01-01

The 5-HT2A receptor is highly involved in aspects of cognition and executive function and seen to be affected in neurodegenerative diseases like Alzheimer's disease and related to the disease pathology. Even though Parkinson's disease (PD) is primarily a motor disorder, reports of impaired executive function are also steadily being associated with this disease. Not much is known about the pathophysiology behind this. The aim of this study was thereby twofold: (1) to investigate 5-HT2A receptor binding levels in Parkinson's brains and (2) to investigate whether PD associated pathology, alpha-synuclein (AS) overexpression, could be associated with 5-HT2A alterations. Binding density for the 5-HT2A-specific radioligand [3H]-MDL 100.907 was measured in membrane suspensions of frontal cortex tissue from PD patients. Protein levels of AS were further measured using western blotting. Results showed higher AS levels accompanied by increased 5-HT2A receptor binding in PD brains. In a separate study, we looked for changes in 5-HT2A receptors in the prefrontal cortex in 52-week-old transgenic mice overexpressing human AS. We performed region-specific 5-HT2A receptor binding measurements followed by gene expression analysis. The transgenic mice showed lower 5-HT2A binding in the frontal association cortex that was not accompanied by changes in gene expression levels. This study is one of the first to look at differences in serotonin receptor levels in PD and in relation to AS overexpression. PMID:27579212

[Foshouningshen decoction improves sleeping via the serotonergic system in a rat model of insomnia].

PubMed

Huang, Jie-Cong; Xie, Wei; Deng, Ning; Liang, Wen-Lin; Hu, Dong-Rong; Hong, Yu; Zhou, Yang

2017-08-20

To evaluate the sedative and hypnotic effects of Foshouningshen decoction (FSNSD) and study its effects on expressions of 5-hydroxy tryptamine (5-HT) and 5-HT1A receptor (5-HT 1A R) in the hippocampus in a rat model of insomnia. Male KM mice were divided into control group, estazolam (0.4 mg/kg daily) group, and low-, moderate-, and high-dose FSNSD groups (daily dose of 12, 24, and 48 g/kg, respectively). After corresponding treatments for 1 week, the mice underwent sleep-inducing test with subthreshold and threshold doses of sodium pentobarbital. Forty-eight male SD rats were randomized into control group, insomnia model group, estazolam group (0.2 mg/kg daily), and low-, moderate-, and high-dose FSNSD groups (with daily dose of 6, 12, and 24 g/kg, respectively). Rat models of insomnia were established by intraperitoneal injection of 4-cholro-dl-phenylalanine (PCPA) at the daily dose of 350 mg/kg for 3 days, after which the rats received corresponding treatments via gavage for 1 week. The performance of the rats in open field test was recorded and the hippocampal expression of 5-HT was detected using ELISA; the expressions of 5-HT 1A R protein and mRNA in the hippocampus were detected using immunohistochemistry and real-time PCR, respectively. In the sleep-inducing test with a subthreshold dose of sodium pentobarbital, the mice treated with high-dose FSNSD showed a significantly higher rate of sleep onset than the control mice (P<0.05); in the test with a threshold dose of sodium pentobarbital, treatment with moderate- and high-dose FSNSD resulted in significantly prolonged sleeping time (P<0.01) and shortened sleep latency (P<0.05) in the mice. The rats in insomnia model group showed increased total distance in open field test (P<0.05) with significantly decreased content of 5-HT (P<0.01) and expressions of 5-HT 1A R protein and mRNA in the hippocampus (P<0.01). Treatment of the rats with estazolam or high-dose FSNSD obviously decreased the total distance in open field test (P<0.05) and increased the content of 5-HT (P<0.05) and expressions of 5-HT 1A R (P<0.01) in the hippocampus of rats with insomnia. FSNSD can produce therapeutic effects on insomnia possibly by increasing 5-HT content and expressions of 5-HT 1A R in the hippocampus.

Autism gene variant causes hyperserotonemia, serotonin receptor hypersensitivity, social impairment and repetitive behavior

PubMed Central

Veenstra-VanderWeele, Jeremy; Muller, Christopher L.; Iwamoto, Hideki; Sauer, Jennifer E.; Owens, W. Anthony; Shah, Charisma R.; Cohen, Jordan; Mannangatti, Padmanabhan; Jessen, Tammy; Thompson, Brent J.; Ye, Ran; Kerr, Travis M.; Carneiro, Ana M.; Crawley, Jacqueline N.; Sanders-Bush, Elaine; McMahon, Douglas G.; Ramamoorthy, Sammanda; Daws, Lynette C.; Sutcliffe, James S.; Blakely, Randy D.

2012-01-01

Fifty years ago, increased whole-blood serotonin levels, or hyperserotonemia, first linked disrupted 5-HT homeostasis to Autism Spectrum Disorders (ASDs). The 5-HT transporter (SERT) gene (SLC6A4) has been associated with whole blood 5-HT levels and ASD susceptibility. Previously, we identified multiple gain-of-function SERT coding variants in children with ASD. Here we establish that transgenic mice expressing the most common of these variants, SERT Ala56, exhibit elevated, p38 MAPK-dependent transporter phosphorylation, enhanced 5-HT clearance rates and hyperserotonemia. These effects are accompanied by altered basal firing of raphe 5-HT neurons, as well as 5HT1A and 5HT2A receptor hypersensitivity. Strikingly, SERT Ala56 mice display alterations in social function, communication, and repetitive behavior. Our efforts provide strong support for the hypothesis that altered 5-HT homeostasis can impact risk for ASD traits and provide a model with construct and face validity that can support further analysis of ASD mechanisms and potentially novel treatments. PMID:22431635

The 5-HT[subscript 3A] Receptor Is Essential for Fear Extinction

ERIC Educational Resources Information Center

Kondo, Makoto; Nakamura, Yukiko; Ishida, Yusuke; Yamada, Takahiro; Shimada, Shoichi

2014-01-01

The 5-HT [subscript 3] receptor, the only ionotropic 5-HT receptor, is expressed in limbic regions, including the hippocampus, amygdala, and cortex. However, it is not known whether it has a role in fear memory processes. Analysis of 5-HT [subscript 3A] receptor knockout mice in fear conditioning paradigms revealed that the 5-HT [subscript 3A]…

Effect of chronic mild stress on serotonergic markers in the skin and brain of the NC/Nga atopic-like mouse strain.

PubMed

Rasul, Aram; El-Nour, Husameldin; Blakely, Randy D; Lonne-Rahm, Sol-Britt; Forsberg, Johan; Johansson, Björn; Theodorsson, Elvar; Nordlind, Klas

2011-11-01

Atopic eczema is often worsened by stress. While acute stress is associated with increased turnover of serotonin (5-hydroxytryptamine; 5-HT), chronic stress causes a decrease. In chronic stress, there is a decrease of the 5-HT1A receptor (R)- and an increase in the 5-HT2AR-responsiveness to 5-HT. In the present study, the impact of chronic mild stress on the expression of 5-HT1A and 5-HT2A receptors and serotonin transporter protein (SERT) was investigated in eczematous skin and brain of atopic-like NC/Nga mice. Twenty-four NC/Nga mice were subjected to chronic mild stress for 12 weeks, and eczema was induced by applying a mite antigen (Dermatophagoides pteronyssinus) on the ears for the last 4 weeks. The mice were divided into three groups, eight per group, stressed eczematous (SE), non-stressed eczematous (NSE) and stressed control (SC). The biopsies were analysed by immunohistochemistry, using a streptavidin-biotin technique. There was an increased number of 5-HT containing dermal mast cell-like mononuclear cells in the skin of mice with eczema (SE and NSE, respectively) compared with the SC, and a tendency to more 5-HT-positive cells in the SE compared with the NSE group. Increased 5-HT1AR immunoreactivity (IR) in the skin and hippocampus of the eczematous groups compared to the control group was seen, but no difference between the SE and NSE groups. The epidermal immunoreactivity for 5-HT2AR was highest in the SE and NSE compared to the SC group, and was also higher in the SE compared to NSE. 5-HT2AR expression was also seen on nerve bundles, the number and intensity of such bundles being decreased in the SE compared to the NSE group. In the CA1 area of the hippocampus, there was an increase in the quantity of cells immunoreactive for 5-HT2AR in the SE versus the NSE group and also in the SE versus the SC group. SERT-IR was found also on nerve bundles with a decreased number in the SE compared to the NSE and SC group. There is a modulation of the expression of serotonergic markers in the eczematous skin and brain of the atopic-like mouse during chronic mild stress.

Novel agonists for serotonin 5-HT7 receptors reverse metabotropic glutamate receptor-mediated long-term depression in the hippocampus of wild-type and Fmr1 KO mice, a model of Fragile X Syndrome

PubMed Central

Costa, Lara; Sardone, Lara M.; Lacivita, Enza; Leopoldo, Marcello; Ciranna, Lucia

2015-01-01

Serotonin 5-HT7 receptors are expressed in the hippocampus and modulate the excitability of hippocampal neurons. We have previously shown that 5-HT7 receptors modulate glutamate-mediated hippocampal synaptic transmission and long-term synaptic plasticity. In particular, we have shown that activation of 5-HT7 receptors reversed metabotropic glutamate receptor-mediated long-term depression (mGluR-LTD) in wild-type (wt) and in Fmr1 KO mice, a mouse model of Fragile X Syndrome in which mGluR-LTD is abnormally enhanced, suggesting that 5-HT7 receptor agonists might be envisaged as a novel therapeutic strategy for Fragile X Syndrome. In this perspective, we have characterized the basic in vitro pharmacokinetic properties of novel molecules with high binding affinity and selectivity for 5-HT7 receptors and we have tested their effects on synaptic plasticity using patch clamp on acute hippocampal slices. Here we show that LP-211, a high affinity selective agonist of 5-HT7 receptors, reverses mGluR-LTD in wt and Fmr1 KO mice, correcting a synaptic malfunction in the mouse model of Fragile X Syndrome. Among novel putative agonists of 5-HT7 receptors, the compound BA-10 displayed improved affinity and selectivity for 5-HT7 receptors and improved in vitro pharmacokinetic properties with respect to LP-211. BA-10 significantly reversed mGluR-LTD in the CA3-CA1 synapse in wt and Fmr1KO mice, indicating that BA-10 behaved as a highly effective agonist of 5-HT7 receptors and reduced exaggerated mGluR-LTD in a mouse model of Fragile X Syndrome. On the other side, the compounds RA-7 and PM-20, respectively arising from in vivo metabolism of LP-211 and BA-10, had no effect on mGluR-LTD thus did not behave as agonists of 5-HT7 receptors in our conditions. The present results provide information about the structure-activity relationship of novel 5-HT7 receptor agonists and indicate that LP-211 and BA-10 might be used as novel pharmacological tools for the therapy of Fragile X Syndrome. PMID:25814945

Important role of mucosal serotonin in colonic propulsion and peristaltic reflexes: in vitro analyses in mice lacking tryptophan hydroxylase 1.

PubMed

Heredia, Dante J; Gershon, Michael D; Koh, Sang Don; Corrigan, Robert D; Okamoto, Takanubu; Smith, Terence K

2013-12-01

Although there is general agreement that mucosal 5-hydroxytryptamine (5-HT) can initiate peristaltic reflexes in the colon, recent studies have differed as to whether or not the role of mucosal 5-HT is critical. We therefore tested the hypothesis that the secretion of 5-HT from mucosal enterochromaffin (EC) cells is essential for the manifestation of murine colonic peristaltic reflexes. To do so, we analysed the mechanisms underlying faecal pellet propulsion in isolated colons of mice lacking tryptophan hydroxylase 1 (Tph1(-/-) mice), which is the rate-limiting enzyme in the biosynthesis of mucosal but not neuronal 5-HT. We used video analysis of faecal pellet propulsion, tension transducers to record colonic migrating motor complexes (CMMCs) and intracellular microelectrodes to record circular muscle activity occurring spontaneously or following intraluminal distension. When compared with control (Tph1(+/+)) mice, Tph1(-/-) animals exhibited: (1) an elongated colon; (2) larger faecal pellets; (3) orthograde propulsion followed by retropulsion (not observed in Tph1(+/+) colon); (4) slower in vitro propulsion of larger faecal pellets (28% of Tph1(+/+)); (5) CMMCs that infrequently propagated in an oral to anal direction because of impaired descending inhibition; (6) reduced CMMCs and inhibitory responses to intraluminal balloon distension; (7) an absence of reflex activity in response to mucosal stimulation. In addition, (8) thin pellets that propagated along the control colon failed to do so in Tph1(-/-) colon; and (9) the 5-HT3 receptor antagonist ondansetron, which reduced CMMCs and blocked their propagation in Tph1(+/+) mice, failed to alter CMMCs in Tph1(-/-) animals. Our observations suggest that mucosal 5-HT is essential for reflexes driven by mucosal stimulation and is also important for normal propagation of CMMCs and propulsion of pellets in the isolated colon.

Covalent complexes of albumin with serotonin, ketanserin and lysergic acid antagonize the activity of serotonin in human platelets

DOE Office of Scientific and Technical Information (OSTI.GOV)

VanderBerg, S.R.; Gonias, S.L.

1989-01-01

Covalent conjugates of bovine serum albumin (BSA) and 5-HT, ketanserin or d-lysergic acid were synthesized and characterized by polyacrylamide gel electrophoresis, whole blood clearance experiments in mice and aggregation studies with human platelets. Using the standard synthesis procedure, each mol of BSA bound 13.4 mol of (/sup 3/H)5-HT. Derivatization did not cause significant protein aggregation as determined by electrophoresis. All three conjugates antagonized the ability of 5-HT to amplify aggregation caused by low concentrations of ADP. The antagonist activity of each conjugate was concentration dependent; 2.6 ..mu..M 5-HT-BSA completely inhibited the aggregation caused by 13 ..mu..M 5-HT. None of themore » BSA drug conjugates, including 5-HT-BSA, amplified platelet aggregation caused by ADP in the absence of 5-HT. Aggregation by ristocetin, collagen, epinephrine or ADP alone was not significantly affected by the conjugates. Whole blood elimination experiments in mice demonstrated that the three conjugates and underivatized BSA are equally stable in the circulation. These prototypic 5-HT drug-protein conjugates may be useful for probing 5-HT/sub 2/ receptor-ligand interactions in human platelets.« less

A Subpopulation of Serotonergic Neurons That Do Not Express the 5-HT1A Autoreceptor

PubMed Central

2012-01-01

5-HT neurons are topographically organized in the hindbrain, and have been implicated in the etiology and treatment of psychiatric diseases such as depression and anxiety. Early studies suggested that the raphe 5-HT neurons were a homogeneous population showing similar electrical properties, and feedback inhibition mediated by 5-HT1A autoreceptors. We utilized histochemistry techniques in ePet1-eGFP and 5-HT1A-iCre/R26R mice to show that a subpopulation of 5-HT neurons do not express the somatodendritic 5-HT1A autoreceptor mRNA. In addition, we performed patch-clamp recordings followed by single-cell PCR in ePet1-eGFP mice. From 134 recorded 5-HT neurons located in the dorsal, lateral, and median raphe, we found lack of 5-HT1A mRNA expression in 22 cells, evenly distributed across raphe subfields. We compared the cellular characteristics of these neuronal types and found no difference in passive membrane properties and general excitability. However, when injected with large depolarizing current, 5-HT1A-negative neurons fired more action potentials, suggesting a lack of autoinhibitory action of local 5-HT release. Our results support the hypothesis that the 5-HT system is composed of subpopulations of serotonergic neurons with different capacity for adaptation. PMID:23336048

Insomnia Caused by Serotonin Depletion is Due to Hypothermia

PubMed Central

Murray, Nicholas M.; Buchanan, Gordon F.; Richerson, George B.

2015-01-01

Study Objective: Serotonin (5-hydroxytryptamine, 5-HT) neurons are now thought to promote wakefulness. Early experiments using the tryptophan hydroxylase inhibitor para-chlorophenylalanine (PCPA) had led to the opposite conclusion, that 5-HT causes sleep, but those studies were subsequently contradicted by electrophysiological and behavioral data. Here we tested the hypothesis that the difference in conclusions was due to failure of early PCPA experiments to control for the recently recognized role of 5-HT in thermoregulation. Design: Adult male C57BL/6N mice were treated with PCPA (800 mg/kg intraperitoneally for 5 d; n = 15) or saline (n = 15), and housed at 20°C (normal room temperature) or at 33°C (thermoneutral for mice) for 24 h. In a separate set of experiments, mice were exposed to 4°C for 4 h to characterize their ability to thermoregulate. Measurements and Results: PCPA treatment reduced brain 5-HT to less than 12% of that of controls. PCPA-treated mice housed at 20°C spent significantly more time awake than controls. However, core body temperature decreased from 36.5°C to 35.1°C. When housed at 33°C, body temperature remained normal, and total sleep duration, sleep architecture, and time in each vigilance state were the same as controls. When challenged with 4°C, PCPA-treated mice experienced a precipitous drop in body temperature, whereas control mice maintained a normal body temperature. Conclusions: These results indicate that early experiments using para-chlorophenylalanine that led to the conclusion that 5-hydroxytryptamine (5-HT) causes sleep were likely confounded by hypothermia. Temperature controls should be considered in experiments using 5-HT depletion. Citation: Murray NM, Buchanan GF, Richerson GB. Insomnia caused by serotonin depletion is due to hypothermia. SLEEP 2015;38(12):1985–1993. PMID:26194567

The Gain-of-Function Integrin β3 Pro33 Variant Alters the Serotonin System in the Mouse Brain.

PubMed

Dohn, Michael R; Kooker, Christopher G; Bastarache, Lisa; Jessen, Tammy; Rinaldi, Capria; Varney, Seth; Mazalouskas, Matthew D; Pan, Hope; Oliver, Kendra H; Velez Edwards, Digna R; Sutcliffe, James S; Denny, Joshua C; Carneiro, Ana M D

2017-11-15

Engagement of integrins by the extracellular matrix initiates signaling cascades that drive a variety of cellular functions, including neuronal migration and axonal pathfinding in the brain. Multiple lines of evidence link the ITGB3 gene encoding the integrin β3 subunit with the serotonin (5-HT) system, likely via its modulation of the 5-HT transporter (SERT). The ITGB3 coding polymorphism Leu33Pro (rs5918, Pl A2 ) produces hyperactive αvβ3 receptors that influence whole-blood 5-HT levels and may influence the risk for autism spectrum disorder (ASD). Using a phenome-wide scan of psychiatric diagnoses, we found significant, male-specific associations between the Pro33 allele and attention-deficit hyperactivity disorder and ASDs. Here, we used knock-in (KI) mice expressing an Itgb3 variant that phenocopies the human Pro33 variant to elucidate the consequences of constitutively enhanced αvβ3 signaling to the 5-HT system in the brain. KI mice displayed deficits in multiple behaviors, including anxiety, repetitive, and social behaviors. Anatomical studies revealed a significant decrease in 5-HT synapses in the midbrain, accompanied by decreases in SERT activity and reduced localization of SERTs to integrin adhesion complexes in synapses of KI mice. Inhibition of focal adhesion kinase (FAK) rescued SERT function in synapses of KI mice, demonstrating that constitutive active FAK signaling downstream of the Pro32Pro33 integrin αvβ3 suppresses SERT activity. Our studies identify a complex regulation of 5-HT homeostasis and behaviors by integrin αvβ3, revealing an important role for integrins in modulating risk for neuropsychiatric disorders. SIGNIFICANCE STATEMENT The integrin β3 Leu33Pro coding polymorphism has been associated with autism spectrum disorders (ASDs) within a subgroup of patients with elevated blood 5-HT levels, linking integrin β3, 5-HT, and ASD risk. We capitalized on these interactions to demonstrate that the Pro33 coding variation in the murine integrin β3 recapitulates the sex-dependent neurochemical and behavioral attributes of ASD. Using state-of-the-art techniques, we show that presynaptic 5-HT function is altered in these mice, and that the localization of 5-HT transporters to specific compartments within the synapse, disrupted by the integrin β3 Pro33 mutation, is critical for appropriate reuptake of 5-HT. Our studies provide fundamental insight into the genetic network regulating 5-HT neurotransmission in the CNS that is also associated with ASD risk. Copyright © 2017 the authors 0270-6474/17/3711272-14$15.00/0.

Abnormal cell-intrinsic and network excitability in the neocortex of serotonin-deficient Pet-1 knockout mice.

PubMed

Puzerey, Pavel A; Kodama, Nathan X; Galán, Roberto F

2016-02-01

Neurons originating from the raphe nuclei of the brain stem are the exclusive source of serotonin (5-HT) to the cortex. Their serotonergic phenotype is specified by the transcriptional regulator Pet-1, which is also necessary for maintaining their neurotransmitter identity across development. Transgenic mice in which Pet-1 is genetically ablated (Pet-1(-/-)) show a dramatic reduction (∼80%) in forebrain 5-HT levels, yet no investigations have been carried out to assess the impact of such severe 5-HT depletion on the function of target cortical neurons. Using whole cell patch-clamp methods, two-dimensional (2D) multielectrode arrays (MEAs), 3D morphological neuronal reconstructions, and animal behavior, we investigated the impact of 5-HT depletion on cortical cell-intrinsic and network excitability. We found significant changes in several parameters of cell-intrinsic excitability in cortical pyramidal cells (PCs) as well as an increase in spontaneous synaptic excitation through 5-HT3 receptors. These changes are associated with increased local network excitability and oscillatory activity in a 5-HT2 receptor-dependent manner, consistent with previously reported hypersensitivity of cortical 5-HT2 receptors. PC morphology was also altered, with a significant reduction in dendritic complexity that may possibly act as a compensatory mechanism for increased excitability. Consistent with this interpretation, when we carried out experiments with convulsant-induced seizures to asses cortical excitability in vivo, we observed no significant differences in seizure parameters between wild-type and Pet-1(-/-) mice. Moreover, MEA recordings of propagating field potentials showed diminished propagation of activity across the cortical sheath. Together these findings reveal novel functional changes in neuronal and cortical excitability in mice lacking Pet-1. Copyright © 2016 the American Physiological Society.

Effects of acute tryptophan depletion on brain serotonin function and concentrations of dopamine and norepinephrine in C57BL/6J and BALB/cJ mice.

PubMed

Biskup, Caroline Sarah; Sánchez, Cristina L; Arrant, Andrew; Van Swearingen, Amanda E D; Kuhn, Cynthia; Zepf, Florian Daniel

2012-01-01

Acute tryptophan depletion (ATD) is a method of lowering brain serotonin (5-HT). Administration of large neutral amino acids (LNAA) limits the transport of endogenous tryptophan (TRP) across the blood brain barrier by competition with other LNAAs and subsequently decreases serotonergic neurotransmission. A recent discussion on the specificity and efficacy of the ATD paradigm for inhibition of central nervous 5-HT has arisen. Moreover, side effects such as vomiting and nausea after intake of amino acids (AA) still limit its use. ATD Moja-De is a revised mixture of AAs which is less nauseating than conventional protocols. It has been used in preliminary clinical studies but its effects on central 5-HT mechanisms and other neurotransmitter systems have not been validated in an animal model. We tested ATD Moja-De (TRP-) in two strains of mice: C57BL/6J, and BALB/cJ, which are reported to have impaired 5-HT synthesis and a more anxious phenotype relative to other strains of mice. ATD Moja-De lowered brain TRP, significantly decreased 5-HT synthesis as indexed by 5-HTP levels after decarboxlyase inhibition, and lowered 5-HT and 5-HIAA in both strains of mice, however more so in C57BL/6J than in BALB/cJ. Dopamine and its metabolites as well as norepinephrine were not affected. A balanced (TRP+) control mixture did not raise 5-HT or 5-HIAA. The present findings suggest that ATD Moja-De effectively and specifically suppresses central serotonergic function. These results also demonstrate a strain-specific effect of ATD Moja-De on anxiety-like behavior.

Abnormal cell-intrinsic and network excitability in the neocortex of serotonin-deficient Pet-1 knockout mice

PubMed Central

Puzerey, Pavel A.; Kodama, Nathan X.

2015-01-01

Neurons originating from the raphe nuclei of the brain stem are the exclusive source of serotonin (5-HT) to the cortex. Their serotonergic phenotype is specified by the transcriptional regulator Pet-1, which is also necessary for maintaining their neurotransmitter identity across development. Transgenic mice in which Pet-1 is genetically ablated (Pet-1−/−) show a dramatic reduction (∼80%) in forebrain 5-HT levels, yet no investigations have been carried out to assess the impact of such severe 5-HT depletion on the function of target cortical neurons. Using whole cell patch-clamp methods, two-dimensional (2D) multielectrode arrays (MEAs), 3D morphological neuronal reconstructions, and animal behavior, we investigated the impact of 5-HT depletion on cortical cell-intrinsic and network excitability. We found significant changes in several parameters of cell-intrinsic excitability in cortical pyramidal cells (PCs) as well as an increase in spontaneous synaptic excitation through 5-HT3 receptors. These changes are associated with increased local network excitability and oscillatory activity in a 5-HT2 receptor-dependent manner, consistent with previously reported hypersensitivity of cortical 5-HT2 receptors. PC morphology was also altered, with a significant reduction in dendritic complexity that may possibly act as a compensatory mechanism for increased excitability. Consistent with this interpretation, when we carried out experiments with convulsant-induced seizures to asses cortical excitability in vivo, we observed no significant differences in seizure parameters between wild-type and Pet-1−/− mice. Moreover, MEA recordings of propagating field potentials showed diminished propagation of activity across the cortical sheath. Together these findings reveal novel functional changes in neuronal and cortical excitability in mice lacking Pet-1. PMID:26609119

Serotonin and corticosterone rhythms in mice exposed to cigarette smoke and in patients with COPD: implication for COPD-associated neuropathogenesis.

PubMed

Sundar, Isaac K; Yao, Hongwei; Huang, Yadi; Lyda, Elizabeth; Sime, Patricia J; Sellix, Michael T; Rahman, Irfan

2014-01-01

The circadian timing system controls daily rhythms of physiology and behavior, and disruption of clock function can trigger stressful life events. Daily exposure to cigarette smoke (CS) can lead to alteration in diverse biological and physiological processes. Smoking is associated with mood disorders, including depression and anxiety. Patients with chronic obstructive pulmonary disease (COPD) have abnormal circadian rhythms, reflected by daily changes in respiratory symptoms and lung function. Corticosterone (CORT) is an adrenal steroid that plays a considerable role in stress and anti-inflammatory responses. Serotonin (5-hydroxytryptamine; 5HT) is a neurohormone, which plays a role in sleep/wake regulation and affective disorders. Secretion of stress hormones (CORT and 5HT) is under the control of the circadian clock in the suprachiasmatic nucleus. Since smoking is a contributing factor in the development of COPD, we hypothesize that CS can affect circadian rhythms of CORT and 5HT secretion leading to sleep and mood disorders in smokers and patients with COPD. We measured the daily rhythms of plasma CORT and 5HT in mice following acute (3 d), sub-chronic (10 d) or chronic (6 mo) CS exposure and in plasma from non-smokers, smokers and patients with COPD. Acute and chronic CS exposure affected both the timing (peak phase) and amplitude of the daily rhythm of plasma CORT and 5HT in mice. Acute CS appeared to have subtle time-dependent effects on CORT levels but more pronounced effects on 5HT. As compared with CORT, plasma 5HT was slightly elevated in smokers but was reduced in patients with COPD. Thus, the effects of CS on plasma 5HT were consistent between mice and patients with COPD. Together, these data reveal a significant impact of CS exposure on rhythms of stress hormone secretion and subsequent detrimental effects on cognitive function, depression-like behavior, mood/anxiety and sleep quality in smokers and patients with COPD.

Yokukansan, a traditional Japanese herbal medicine, enhances the anxiolytic effect of fluvoxamine and reduces cortical 5-HT2A receptor expression in mice.

PubMed

Ohno, Rintaro; Miyagishi, Hiroko; Tsuji, Minoru; Saito, Atsumi; Miyagawa, Kazuya; Kurokawa, Kazuhiro; Takeda, Hiroshi

2018-04-24

Yokukansan is a traditional Japanese herbal medicine that has been approved in Japan as a remedy for neurosis, insomnia, and irritability in children. It has also been reported to improve behavioral and psychological symptoms in patients with various forms of dementia. To evaluate the usefulness of co-treatment with an antidepressant and an herbal medicine in the psychiatric field, the current study examined the effect of yokukansan on the anxiolytic-like effect of fluvoxamine in mice. The anxiolytic-like effect in mice was estimated by the contextual fear conditioning paradigm. Contextual fear conditioning consisted of two sessions, i.e., day 1 for the conditioning session and day 2 for the test session. The expression levels of 5-HT 1A and 5-HT 2A receptor in the mouse brain regions were quantified by western blot analysis. A single administration of fluvoxamine (5-20 mg/kg, i.p.) before the test session dose-dependently and significantly suppressed freezing behavior in mice. In the combination study, a sub-effective dose of fluvoxamine (5 mg/kg, i.p.) significantly suppressed freezing behavior in mice that had been repeatedly pretreated with yokukansan (0.3 and 1 g/kg, p.o.) once a day for 6 days after the conditioning session. Western blot analysis revealed that the expression level of 5-HT 2A receptor was specifically decreased in the prefrontal cortex of mice that had been administered yokukansan and fluvoxamine. Furthermore, microinjection of the 5-HT 2A receptor antagonist ketanserin (5 nmol/mouse) into the prefrontal cortex significantly suppressed freezing behavior. The present findings indicate that repeated treatment with yokukansan synergistically enhances the anxiolytic-like effect of fluvoxamine in the contextual fear conditioning paradigm in mice in conjunction with a decrease in 5-HT 2A receptor-mediated signaling in the prefrontal cortex. Therefore, combination therapy with fluvoxamine and yokukansan may be beneficial for the treatment of anxiety disorders. Copyright © 2018 Elsevier B.V. All rights reserved.

Effect of aging and Alzheimer's disease-like pathology on brain monoamines in mice.

PubMed

Von Linstow, C U; Severino, M; Metaxas, A; Waider, J; Babcock, A A; Lesch, K P; Gramsbergen, J B; Finsen, B

2017-09-01

Aging is the greatest single risk factor of the neurodegenerative disorder Alzheimer's disease (AD). The monoaminergic system, including serotonin (5-HT), dopamine (DA) and noradrenaline (NA) modulates cognition, which is affected in AD. Changes in monoamine levels have been observed in AD, but these can both be age- and/or disease-related. We examined whether brain monoamine levels change as part of physiological aging and/or AD-like disease in APP SWE /PS1 ΔE9 (APP/PS1) transgenic mice. The neocortex, hippocampus, striatum, brainstem and cerebellum of 6-, 12-, 18- and 24-month-old B6C3 wild-type (WT) mice and of 18-month old APP/PS1 and WT mice were analysed for 5-HT, DA and NA contents by high pressure liquid chromatography (HPLC), along with neocortex from 14-month-old APP/PS1 and WT mice. While, we observed no aging effect in WT mice, we detected region-specific changes in the levels of all monoamines in 18-month-old transgenic compared with WT mice. This included reductions in 5-HT (-30%), DA (-47%) and NA (-32%) levels in the neocortex and increases of 5-HT in the brainstem (+18%). No changes were observed in any of the monoamines in the neocortex from 14-month-old APP/PS1 mice. In combination, these findings indicate that aging alone is not sufficient to affect brain monoamine levels, unlike the APP SWE /PS1 ΔE9 genotype. Copyright © 2017 Elsevier Ltd. All rights reserved.

Stimulation of 5-HT2C Receptors Improves Cognitive Deficits Induced by Human Tryptophan Hydroxylase 2 Loss of Function Mutation

PubMed Central

Del'Guidice, Thomas; Lemay, Francis; Lemasson, Morgane; Levasseur-Moreau, Jean; Manta, Stella; Etievant, Adeline; Escoffier, Guy; Doré, François Y; Roman, François S; Beaulieu, Jean-Martin

2014-01-01

Polymorphisms in the gene encoding the serotonin synthesis enzyme Tph2 have been identified in mental illnesses, including bipolar disorder, major depression, autism, schizophrenia, and ADHD. Deficits in cognitive flexibility and perseverative behaviors are shared common symptoms in these disorders. However, little is known about the impact of Tph2 gene variants on cognition. Mice expressing a human TPH2 variant (Tph2-KI) were used to investigate cognitive consequences of TPH2 loss of function and pharmacological treatments. We applied a recently developed behavioral assay, the automated H-maze, to study cognitive functions in Tph2-KI mice. This assay involves the consecutive discovery of three different rules: a delayed alternation task, a non-alternation task, and a delayed reversal task. Possible contribution of locomotion, reward, and sensory perception were also investigated. The expression of loss-of-function mutant Tph2 in mice was associated with impairments in reversal learning and cognitive flexibility, accompanied by perseverative behaviors similar to those observed in human clinical studies. Pharmacological restoration of 5-HT synthesis with 5-hydroxytryptophan or treatment with the 5-HT2C receptor agonist CP809.101 reduced cognitive deficits in Tph2-KI mice and abolished perseveration. In contrast, treatment with the psychostimulant methylphenidate exacerbated cognitive deficits in mutant mice. Results from this study suggest a contribution of TPH2 in the regulation of cognition. Furthermore, identification of a role for a 5-HT2 receptor agonist as a cognition-enhancing agent in mutant mice suggests a potential avenue to explore for the personalized treatment of cognitive symptoms in humans with reduced 5-HT synthesis and TPH2 polymorphisms. PMID:24196946

Inhibition of peritoneal dissemination of colon cancer by hyperthermic CO2 insufflation: A novel approach to prevent intraperitoneal tumor spread

PubMed Central

Zhou, Houming; Zheng, Minhua

2017-01-01

Background The increasing use of laparoscopic surgery for advanced gastrointestinal cancer raises concerns about intra-peritoneal tumor spread. Prevention of peritoneal dissemination is extremely important but a preventive modality is lacking. The aim of this study was to examine a novel approach (hyperthermic CO2 insufflation, HT-CO2) for preventing peritoneal dissemination during laparoscopic surgery. Methods A peritoneal dissemination model was established in Balb/c nu/nu mice by intraperitoneal injection of human colon cancer cells (SW1116, 1×106). The mice (n = 48) were subsequently randomized into two groups and subjected to hyperthermic CO2 (43°C, >95% humidity, HT-CO2 group) or standard normothermic CO2 (21°C, <1% relative humidity, NT-CO2 group) insufflation for 3 hours. The mice were sacrificed 28 days later. The peritoneal dissemination was quantitatively analyzed by counting and weighing the peritoneal nodules. The port sites and ascites volume were measured. The peritoneal damage of HT-CO2 was histologically examined with light microscopy and scanning electron microscopy. Intra-abdominal adhesions were evaluated 4 weeks later. Results The number of peritoneal nodules in the HT-CO2 group was significantly less than that in the NT-CO2 group (10.21±3.72 vs. 67.12±5.49, P<0.01). The mean weight of metastatic tumors in the HT-CO2 group was significantly lower than that in the NT-CO2 group (0.31±0.10g vs. 2.16±0.31g, P<0.01). Massive ascites were found in the NT-CO2 group while significantly less ascites developed in HT-CO2- treated mice (8.26±0.31ml vs. 1.27±0.28ml, P<0.01). No port-site metastases were detected in the HT-CO2 group while the incidence of the NT-CO2 group was 12.5% (3/24). HT-CO2 subjection resulted in slight peritoneal damage; the peritoneum returned to normal within five days. No adhesions formed after HT-CO2 treatment. Conclusions HT-CO2 can suppress peritoneal dissemination of colon cancer cells and only causes slight and transient peritoneal damage. HT-CO2 may serve as a promising adjuvant treatment for preventing peritoneal dissemination in laparoscopic resection of advanced colorectal cancer. PMID:28207849

Inhibition of peritoneal dissemination of colon cancer by hyperthermic CO2 insufflation: A novel approach to prevent intraperitoneal tumor spread.

PubMed

Peng, Yuanfei; Yang, Hua; Ye, Qing; Zhou, Houming; Zheng, Minhua; Shi, Yinghong

2017-01-01

The increasing use of laparoscopic surgery for advanced gastrointestinal cancer raises concerns about intra-peritoneal tumor spread. Prevention of peritoneal dissemination is extremely important but a preventive modality is lacking. The aim of this study was to examine a novel approach (hyperthermic CO2 insufflation, HT-CO2) for preventing peritoneal dissemination during laparoscopic surgery. A peritoneal dissemination model was established in Balb/c nu/nu mice by intraperitoneal injection of human colon cancer cells (SW1116, 1×106). The mice (n = 48) were subsequently randomized into two groups and subjected to hyperthermic CO2 (43°C, >95% humidity, HT-CO2 group) or standard normothermic CO2 (21°C, <1% relative humidity, NT-CO2 group) insufflation for 3 hours. The mice were sacrificed 28 days later. The peritoneal dissemination was quantitatively analyzed by counting and weighing the peritoneal nodules. The port sites and ascites volume were measured. The peritoneal damage of HT-CO2 was histologically examined with light microscopy and scanning electron microscopy. Intra-abdominal adhesions were evaluated 4 weeks later. The number of peritoneal nodules in the HT-CO2 group was significantly less than that in the NT-CO2 group (10.21±3.72 vs. 67.12±5.49, P<0.01). The mean weight of metastatic tumors in the HT-CO2 group was significantly lower than that in the NT-CO2 group (0.31±0.10g vs. 2.16±0.31g, P<0.01). Massive ascites were found in the NT-CO2 group while significantly less ascites developed in HT-CO2- treated mice (8.26±0.31ml vs. 1.27±0.28ml, P<0.01). No port-site metastases were detected in the HT-CO2 group while the incidence of the NT-CO2 group was 12.5% (3/24). HT-CO2 subjection resulted in slight peritoneal damage; the peritoneum returned to normal within five days. No adhesions formed after HT-CO2 treatment. HT-CO2 can suppress peritoneal dissemination of colon cancer cells and only causes slight and transient peritoneal damage. HT-CO2 may serve as a promising adjuvant treatment for preventing peritoneal dissemination in laparoscopic resection of advanced colorectal cancer.

5-HT2C Agonists Modulate Schizophrenia-Like Behaviors in Mice.

PubMed

Pogorelov, Vladimir M; Rodriguiz, Ramona M; Cheng, Jianjun; Huang, Mei; Schmerberg, Claire M; Meltzer, Herbert Y; Roth, Bryan L; Kozikowski, Alan P; Wetsel, William C

2017-10-01

All FDA-approved antipsychotic drugs (APDs) target primarily dopamine D 2 or serotonin (5-HT 2A ) receptors, or both; however, these medications are not universally effective, they may produce undesirable side effects, and provide only partial amelioration of negative and cognitive symptoms. The heterogeneity of pharmacological responses in schizophrenic patients suggests that additional drug targets may be effective in improving aspects of this syndrome. Recent evidence suggests that 5-HT 2C receptors may be a promising target for schizophrenia since their activation reduces mesolimbic nigrostriatal dopamine release (which conveys antipsychotic action), they are expressed almost exclusively in CNS, and have weight-loss-promoting capabilities. A difficulty in developing 5-HT 2C agonists is that most ligands also possess 5-HT 2B and/or 5-HT 2A activities. We have developed selective 5-HT 2C ligands and herein describe their preclinical effectiveness for treating schizophrenia-like behaviors. JJ-3-45, JJ-3-42, and JJ-5-34 reduced amphetamine-stimulated hyperlocomotion, restored amphetamine-disrupted prepulse inhibition, improved social behavior, and novel object recognition memory in NMDA receptor hypofunctioning NR1-knockdown mice, and were essentially devoid of catalepsy. However, they decreased motivation in a breakpoint assay and did not promote reversal learning in MK-801-treated mice. Somewhat similar effects were observed with lorcaserin, a 5-HT 2C agonist with potent 5-HT 2B and 5-HT 2A agonist activities, which is approved for treating obesity. Microdialysis studies revealed that both JJ-3-42 and lorcaserin reduced dopamine efflux in the infralimbic cortex, while only JJ-3-42 decreased it in striatum. Collectively, these results provide additional evidence that 5-HT 2C receptors are suitable drug targets with fewer side effects, greater therapeutic selectivity, and enhanced efficacy for treating schizophrenia and related disorders than current APDs.

Gut microbiota regulates maturation of the adult enteric nervous system via enteric serotonin networks.

PubMed

De Vadder, Filipe; Grasset, Estelle; Mannerås Holm, Louise; Karsenty, Gérard; Macpherson, Andrew J; Olofsson, Louise E; Bäckhed, Fredrik

2018-06-19

The enteric nervous system (ENS) is crucial for essential gastrointestinal physiologic functions such as motility, fluid secretion, and blood flow. The gut is colonized by trillions of bacteria that regulate host production of several signaling molecules including serotonin (5-HT) and other hormones and neurotransmitters. Approximately 90% of 5-HT originates from the intestine, and activation of the 5-HT 4 receptor in the ENS has been linked to adult neurogenesis and neuroprotection. Here, we tested the hypothesis that the gut microbiota could induce maturation of the adult ENS through release of 5-HT and activation of 5-HT 4 receptors. Colonization of germ-free mice with a microbiota from conventionally raised mice modified the neuroanatomy of the ENS and increased intestinal transit rates, which was associated with neuronal and mucosal 5-HT production and the proliferation of enteric neuronal progenitors in the adult intestine. Pharmacological modulation of the 5-HT 4 receptor, as well as depletion of endogenous 5-HT, identified a mechanistic link between the gut microbiota and maturation of the adult ENS through the release of 5-HT and activation of the 5-HT 4 receptor. Taken together, these findings show that the microbiota modulates the anatomy of the adult ENS in a 5-HT-dependent fashion with concomitant changes in intestinal transit. Copyright © 2018 the Author(s). Published by PNAS.

Serotonin Improves High Fat Diet Induced Obesity in Mice.

PubMed

Watanabe, Hitoshi; Nakano, Tatsuya; Saito, Ryo; Akasaka, Daisuke; Saito, Kazuki; Ogasawara, Hideki; Minashima, Takeshi; Miyazawa, Kohtaro; Kanaya, Takashi; Takakura, Ikuro; Inoue, Nao; Ikeda, Ikuo; Chen, Xiangning; Miyake, Masato; Kitazawa, Haruki; Shirakawa, Hitoshi; Sato, Kan; Tahara, Kohji; Nagasawa, Yuya; Rose, Michael T; Ohwada, Shyuichi; Watanabe, Kouichi; Aso, Hisashi

2016-01-01

There are two independent serotonin (5-HT) systems of organization: one in the central nervous system and the other in the periphery. 5-HT affects feeding behavior and obesity in the central nervous system. On the other hand, peripheral 5-HT also may play an important role in obesity, as it has been reported that 5-HT regulates glucose and lipid metabolism. Here we show that the intraperitoneal injection of 5-HT to mice inhibits weight gain, hyperglycemia and insulin resistance and completely prevented the enlargement of intra-abdominal adipocytes without having any effect on food intake when on a high fat diet, but not on a chow diet. 5-HT increased energy expenditure, O2 consumption and CO2 production. This novel metabolic effect of peripheral 5-HT is critically related to a shift in the profile of muscle fiber type from fast/glycolytic to slow/oxidative in soleus muscle. Additionally, 5-HT dramatically induced an increase in the mRNA expression of peroxisome proliferator-activated receptor coactivator 1α (PGC-1α)-b and PGC-1α-c in soleus muscle. The elevation of these gene mRNA expressions by 5-HT injection was inhibited by treatment with 5-HT receptor (5HTR) 2A or 7 antagonists. Our results demonstrate that peripheral 5-HT may play an important role in the relief of obesity and other metabolic disorders by accelerating energy consumption in skeletal muscle.

Serotonin abnormalities in Engrailed-2 knockout mice: New insight relevant for a model of Autism Spectrum Disorder.

PubMed

Viaggi, Cristina; Gerace, Claudio; Pardini, Carla; Corsini, Giovanni U; Vaglini, Francesca

2015-08-01

Autism spectrum disorder (ASD) is a congenital neurodevelopmental behavioral disorder that appears in early childhood. Recent human genetic studies identified the homeobox transcription factor, Engrailed 2 (EN2), as a possible ASD susceptibility gene. En2 knockout mice (En2-/-) display subtle cerebellar neuropathological changes and reduced levels of tyrosine hydroxylase, noradrenaline and serotonin in the hippocampus and cerebral cortex similar to those ones which have been observed in the ASD brain. Furthermore other similarities link En2 knockout mice to ASD patients. Several lines of evidence suggest that serotonin may play an important role in the pathophysiology of the disease. In the present study we measured, by using an HPLC, the 5-HT levels in different brain areas and at different ages in En2-/- mice. In the frontal and occipital cortex, the content of 5HT was reduced in En2-/- 1 and 3 months old mice; in 6 month old mice, the difference was still present, but it was not statistically significant. The 5-HT content of cerebellar cortex was significantly reduced at 1 month old but significantly high when the KO mice reached 3 months of age. The increase was present even at 6 months of age. A similar trend was highlighted by SERT immunolabeling in En2-/- mice compared to control in the same areas and age analyzed. Our findings, in agreement with the current knowledge on the 5-HT system alterations in ASD, confirm the early neurotransmitter deficit with a late compensatory recovery in En2 KO-mice further suggesting that this experimental animal may be considered a good predictive model for the human disease. Copyright © 2015 Elsevier Ltd. All rights reserved.

[Effect of bitumen fume on neurotransmitter and ultrastructure in mice brain].

PubMed

Li, Hai-Ling; Guo, Xiang-Yun; Feng, San-Wei; Liu, Chang-Hai

2006-12-01

To observe the effects of bitumen fume on neurotransmitter and ultrastructure of mice brain and to investigate the toxicity of bitumen fume on nerve system of mice brain. The experimental mice were forced to inhale the bitumen fume at different exposure level and in different time periods. The contents of the three transmitters dopamine (DA), norepinephrine (NE), 5-hydroxytryptamine (5-HT) in mice brain were measured by the fluorescence meanwhile ultrastructure of mice brain was observed by electronic microscope. The ultrastructure of mice brain was observed under transmission electron microscopy. The contents of DA, NE and 5-HT in all groups decreased with the increasing of dose and prolonging of time (after 8 week, with the increasing of exposure lever, the content of DA, NE, 5-HT was respectively 2.194, 2.190, 2.181, 2.178 microg/g and 1.148, 1.138, 1.135 and 1.407, 1.403, 1.395 microg), but the results did not show significant differences. The structure of the mitochondria changes included the swollen mitochondria, chromatin margination, pyknosis and apoptosis in neuro cells and the processes of swollen astrocyte cells. The bitumen fume could induce changes of the ultrastructure of mice brain and affect the contents of neurotransmitter of mice brain.

5-HT6 receptor blockade regulates primary cilia morphology in striatal neurons.

PubMed

Brodsky, Matthew; Lesiak, Adam J; Croicu, Alex; Cohenca, Nathalie; Sullivan, Jane M; Neumaier, John F

2017-04-01

The 5-HT 6 receptor has been implicated in a variety of cognitive processes including habitual behaviors, learning, and memory. It is found almost exclusively in the brain, is expressed abundantly in striatum, and localizes to neuronal primary cilia. Primary cilia are antenna-like, sensory organelles found on most neurons that receive both chemical and mechanical signals from other cells and the surrounding environment; however, the effect of 5-HT 6 receptor function on cellular morphology has not been examined. We confirmed that 5-HT 6 receptors were localized to primary cilia in wild-type (WT) but not 5-HT 6 knockout (5-HT 6 KO) in both native mouse brain tissue and primary cultured striatal neurons then used primary neurons cultured from WT or 5-HT 6 KO mice to study the function of these receptors. Selective 5-HT 6 antagonists reduced cilia length in neurons cultured from wild-type mice in a concentration and time-dependent manner without altering dendrites, but had no effect on cilia length in 5-HT 6 KO cultured neurons. Varying the expression levels of heterologously expressed 5-HT 6 receptors affected the fidelity of ciliary localization in both WT and 5-HT 6 KO neurons; overexpression lead to increasing amounts of 5-HT 6 localization outside of the cilia but did not alter cilia morphology. Introducing discrete mutations into the third cytoplasmic loop of the 5-HT 6 receptor greatly reduced, but did not entirely eliminate, trafficking of the 5-HT 6 receptor to primary cilia. These data suggest that blocking 5-HT 6 receptor activity reduces the length of primary cilia and that mechanisms that regulate trafficking of 5-HT 6 receptors to cilia are more complex than previously thought. Copyright © 2017 Elsevier B.V. All rights reserved.

Pharmacological aspects of metaldehyde poisoning in mice.

PubMed

Homeida, A M; Cooke, R G

1982-03-01

Metaldehyde, when administered orally to mice at a dose of 1 g kg-1, produced convulsions and death within 2 h. Brain concentrations of noradrenaline (NA) 5-hydroxytryptamie (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) were significantly reduced in these animals relative to controls. Treatment with either intraperitoneal clonidine or diazepam 20 min after administration of metaldehyde reduced the mortality rate and in mice surviving for 5 h, the decrease in brain NA and 5-HT concentrations were significantly reduced.

MicroRNA-Dependent Control of Serotonin-Induced Pulmonary Arterial Contraction.

PubMed

Dahan, Diana; Hien, Tran Thi; Tannenberg, Philip; Ekman, Mari; Rippe, Catarina; Boettger, Thomas; Braun, Thomas; Tran-Lundmark, Karin; Tran, Phan-Kiet; Swärd, Karl; Albinsson, Sebastian

2017-01-01

Serotonin (5-HT) is considered to play a role in pulmonary arterial hypertension by regulating vascular remodeling and smooth muscle contractility. Here, arteries from mice with inducible and smooth muscle-specific deletion of Dicer were used to address mechanisms by which microRNAs control 5-HT-induced contraction. Mice were used 5 weeks after Dicer deletion, and pulmonary artery contractility was analyzed by wire myography. No change was seen in right ventricular systolic pressure following dicer deletion, but systemic blood pressure was reduced. Enhanced 5-HT-induced contraction in Dicer KO pulmonary arteries was associated with increased 5-HT2A receptor mRNA expression whereas 5-HT1B and 5-HT2B receptor mRNAs were unchanged. Contraction by the 5-HT2A agonist TCB-2 was increased in Dicer KO as was the response to the 5-HT2B agonist BW723C86. Effects of Src and protein kinase C inhibition were similar in control and KO arteries, but the effect of inhibition of Rho kinase was reduced. We identified miR-30c as a potential candidate for 5-HT2A receptor regulation as it repressed 5-HT2A mRNA and protein. Our findings show that 5-HT receptor signaling in the arterial wall is subject to regulation by microRNAs and that this entails altered 5-HT2A receptor expression and signaling. © 2017 S. Karger AG, Basel.

Serotonergic modulation of nicotine-induced kinetic tremor in mice.

PubMed

Kunisawa, Naofumi; Iha, Higor A; Nomura, Yuji; Onishi, Misaki; Matsubara, Nami; Shimizu, Saki; Ohno, Yukihiro

2017-06-01

We previously demonstrated that nicotine elicited kinetic tremor by elevating the neural activity of the inferior olive via α7 nicotinic acetylcholine (nACh) receptors. Since α7 nACh receptors reportedly facilitate synaptic monoamine release, we explored the role of 5-HT receptors in induction and/or modulation of nicotine tremor. Treatment of mice with nicotine induced kinetic tremor that normally appeared during movement. The 5-HT 1A agonist, 8-hydroxydipropylaminotetraline (8-OH-DPAT), significantly enhanced nicotine-induced tremor and the action of 8-OH-DPAT was antagonized by WAY-100135 (5-HT 1A antagonist). In addition, the cerebral 5-HT depletion by repeated treatment with p-chlorophenylalanine did not reduce, but rather potentiated the facilitatory effects of 8-OH-DPAT. In contrast, the 5-HT 2 agonist, 2,5-dimethoxy-4-iodoamphetamine (DOI), significantly attenuated nicotine tremor, which was antagonized by ritanserin (5-HT 2 antagonist). The 5-HT 3 agonist SR-57227 did not affect nicotine-induced tremor. Furthermore, when testing the direct actions of 5-HT antagonists, nicotine tremor was inhibited by WAY-100135, but was unaffected by ritanserin, ondansetron (5-HT 3 antagonist) or SB-258585 (5-HT 6 antagonist). These results suggest that postsynaptic 5-HT 1A receptors are involved in induction of nicotine tremor mediated by α7 nACh receptors. In addition, 5-HT 2 receptors have an inhibitory modulatory role in induction of nicotine tremor. Copyright © 2017 The Authors. Production and hosting by Elsevier B.V. All rights reserved.

Social deficits and perseverative behaviors, but not overt aggression, in MAO-A hypomorphic mice.

PubMed

Bortolato, Marco; Chen, Kevin; Godar, Sean C; Chen, Gao; Wu, Weihua; Rebrin, Igor; Farrell, Mollee R; Scott, Anna L; Wellman, Cara L; Shih, Jean C

2011-12-01

Monoamine oxidase (MAO)-A is a key enzyme for the degradation of brain serotonin (5-hydroxytryptamine, 5-HT) and norepinephrine (NE). In humans and mice, total MAO-A deficiency results in high 5-HT and NE levels, as well as elevated reactive aggression. Here we report the generation of MAO-A(Neo) mice, a novel line of hypomorphic MAO-A mutants featuring the insertion of a floxed neomycin-resistance cassette in intron-12 of the Maoa gene. This construct resulted in a chimeric, non-functional variant of the Maoa-Neo transcript, with a truncated C-terminus, likely due to aberrant splicing; these deficits notwithstanding, small amounts of functional Maoa transcript were found in the brain of MAO-A(Neo) mice. In the prefrontal cortex and amygdala, MAO-A(Neo) mice showed low, yet detectable, MAO-A catalytic activity, as well as 5-HT levels equivalent to WT littermates; conversely, the hippocampus and midbrain of MAO-A(Neo) mice featured a neurochemical profile akin to MAO-A-knockout (KO) mice, with undetectable MAO-A activity and high 5-HT concentrations. MAO-A(Neo) mice showed significant increases in dendritic length in the pyramidal neurons of orbitofrontal cortex, but not basolateral amygdala, in comparison with WT littermates; by contrast, the orbitofrontal cortex of MAO-A KO mice showed significant reductions in basilar dendritic length, as well as a profound increase in apical dendritic length. MAO-A(Neo) mice showed a unique set of behavioral abnormalities, encompassing reduced open-field locomotion, perseverative responses, such as marble burying and water mist-induced grooming, and a lack of anxiety-like behaviors in the elevated plus-maze and light-dark box paradigms. Notably, whereas MAO-A(Neo) and KO mice showed significant reductions in social interaction, only the latter genotype showed increases in resident-intruder aggression. Taken together, our findings indicate that MAO A hypomorphism results in behavioral and morphological alterations distinct from those featured by MAO-A KO mice.

Cell type-specific in vivo expression of genes encoding signalling molecules in the brain in response to chronic mild stress and chronic treatment with fluoxetine.

PubMed

Dong, Lu; Li, Baoman; Verkhratsky, Alexei; Peng, Liang

2015-08-01

Previously, we reported that chronic treatment with fluoxetine increased gene expression of 5-hydroxytryptamine receptor 2B (5-HT2BR), cytosolic phospholipase 2α (cPLA2α), glutamate receptor, ionotropic kainate 2 (GluK2) and adenosine deaminase acting on RNA 2 (ADAR2), in cultured astrocytes and astrocytes freshly isolated from transgenic mice tagged with an astrocyte-specific marker. In contrast, neurones isolated from transgenic mice tagged with a neurone-specific marker and exposed to fluoxetine showed an increase in gene expression of glutamate receptor, ionotropic kainate 4 (GluK4) and 5-hydroxytryptamine receptor 2C (5-HT2CR). In a mouse model of anhedonia, the downregulation of 5-HT2BR, cPLA2α, ADAR2 and GluK4 but not GluK2 and 5-HT2CR was detected. To investigate the effects of chronic mild stress (CMS) and/or fluoxetine treatment on gene expression of 5-HT2BR, 5-HT2CR, cPLA2α, ADAR2, GluK2 and GluK4 specifically in astrocytes and neurones. Transgenic mice tagged with either astrocyte- or neurone-specific markers were exposed to the CMS. Real-time PCR was applied to determine expression of messenger RNA (mRNA). We found that (i) mRNAs of the 5-HT2BR and cPLA2α in astrocytes and GluK4 in neurones were significantly reduced in mice that became anhedonic; the mRNA levels were restored by fluoxetine treatment; (ii) ADAR2 in astrocytes was decreased by the CMS but showed no response to fluoxetine in anhedonic animals; (iii) neither GluK2 expression in astrocytes nor 5-HT2CR expression in neurones were affected in anhedonic animals, although expression of 5-HT2CR mRNA was upregulated by fluoxetine. Our results indicate that the effects of chronic treatment with fluoxetine are not only dependent on the cell type studied but also on the development of anhedonia. This suggests that fluoxetine may affect major depression (MD) patients and healthy people in a different manner.

Hexim1 heterozygosity stabilizes atherosclerotic plaque and decreased steatosis in ApoE null mice fed atherogenic diet.

PubMed

Dhar-Mascareno, Manya; Rozenberg, Inna; Iqbal, Jahangir; Hussain, M Mahmood; Beckles, Daniel; Mascareno, Eduardo

2017-02-01

Hexim-1 is an inhibitor of RNA polymerase II transcription elongation. Decreased Hexim-1 expression in animal models of chronic diseases such as left ventricular hypertrophy, obesity and cancer triggered significant changes in adaptation and remodeling. The main aim of this study was to evaluate the role of Hexim1 in lipid metabolism focused in the progression of atherosclerosis and steatosis. We used the C57BL6 apolipoprotein E (ApoE null) crossed bred to C57BL6Hexim1 heterozygous mice to obtain ApoE null - Hexim1 heterozygous mice (ApoE-HT). Both ApoE null backgrounds were fed high fat diet for twelve weeks. Then, we evaluated lipid metabolism, atherosclerotic plaque formation and liver steatosis. In order to understand changes in the transcriptome of both backgrounds during the progression of steatosis, we performed Affymetrix mouse 430 2.0 microarray. After 12 weeks of HFD, ApoE null and ApoE-HT showed similar increase of cholesterol and triglycerides in plasma. Plaque composition was altered in ApoE-HT. Additionally, liver triglycerides and steatosis were decreased in ApoE-HT mice. Affymetrix analysis revealed that decreased steatosis might be due to impaired inducible SOCS3 expression in ApoE-HT mice. In conclusion, decreased Hexim-1 expression does not alter cholesterol metabolism in ApoE null background after HFD. However, it promotes stable atherosclerotic plaque and decreased steatosis by promoting the anti-inflammatory TGFβ pathway and blocking the expression of the inducible and pro-inflammatory expression of SOCS3 respectively. Published by Elsevier Ltd.

Experimental febrile seizures induce age-dependent structural plasticity and improve memory in mice.

PubMed

Tao, K; Ichikawa, J; Matsuki, N; Ikegaya, Y; Koyama, R

2016-03-24

Population-based studies have demonstrated that children with a history of febrile seizure (FS) perform better than age-matched controls at hippocampus-dependent memory tasks. Here, we report that FSs induce two distinct structural reorganizations in the hippocampus and bidirectionally modify future learning abilities in an age-dependent manner. Compared with age-matched controls, adult mice that had experienced experimental FSs induced by hyperthermia (HT) on postnatal day 14 (P14-HT) performed better in a cognitive task that requires dentate granule cells (DGCs). The enhanced memory performance correlated with an FS-induced persistent increase in the density of large mossy fiber terminals (LMTs) of the DGCs. The memory enhancement was not observed in mice that had experienced HT-induced seizures at P11 which exhibited abnormally located DGCs in addition to the increased LMT density. The ectopic DGCs of the P11-HT mice were abolished by the diuretic bumetanide, and this pharmacological treatment unveiled the masked memory enhancement. Thus, this work provides a novel basis for age-dependent structural plasticity in which FSs influence future brain function. Copyright © 2016 IBRO. Published by Elsevier Ltd. All rights reserved.

Low-tar and high-tar cigarettes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holt, P.G.; Chalmer, J.E.; Roberts, L.M.

Mice were exposed for 7 to 8 minutes on weekdays to fresh smoke from high-tar (HT) or low-tar (LT) cigarettes for varying periods of up to 36 weeks. Mice exposed to HT cigarettes exhibited more marked alterations in humoral immune responsiveness, hematological profiles, and pulmonary pathologic findings than those exposed to LT cigarettes. However, cell-mediated immune responsiveness to both bacterial and tumor-specific antigens was depressed similarly in animals exposed to HT or LT cigarettes. Furthermore, the growth rates of subcutaneously established tumors were enhanced similarly in the two groups, with respect to those in control animals.

Loss of GluN2D subunit results in social recognition deficit, social stress, 5-HT2C receptor dysfunction, and anhedonia in mice.

PubMed

Yamamoto, Hideko; Kamegaya, Etsuko; Hagino, Yoko; Takamatsu, Yukio; Sawada, Wakako; Matsuzawa, Maaya; Ide, Soichiro; Yamamoto, Toshifumi; Mishina, Masayoshi; Ikeda, Kazutaka

2017-01-01

The N-methyl-d-aspartate (NMDA) receptor channel is involved in various physiological functions, including learning and memory. The GluN2D subunit of the NMDA receptor has low expression in the mature brain, and its role is not fully understood. In the present study, the effects of GluN2D subunit deficiency on emotional and cognitive function were investigated in GluN2D knockout (KO) mice. We found a reduction of motility (i.e., a depressive-like state) in the tail suspension test and a reduction of sucrose preference (i.e., an anhedonic state) in GluN2D KO mice that were group-housed with littermates. Despite apparently normal olfactory function and social interaction, GluN2D KO mice exhibited a decrease in preference for social novelty, suggesting a deficit in social recognition or memory. Golgi-Cox staining revealed a reduction of the complexity of dendritic trees in the accessory olfactory bulb in GluN2D KO mice, suggesting a deficit in pheromone processing pathway activation, which modulates social recognition. The deficit in social recognition may result in social stress in GluN2D KO mice. Isolation housing is a procedure that has been shown to reduce stress in mice. Interestingly, 3-week isolation and treatment with agomelatine or the 5-hydroxytryptamine-2C (5-HT 2C ) receptor antagonist SB242084 reversed the anhedonic-like state in GluN2D KO mice. In contrast, treatment with the 5-HT 2C receptor agonist CP809101 induced depressive- and anhedonic-like states in isolated GluN2D KO mice. These results suggest that social stress that is caused by a deficit in social recognition desensitizes 5-HT 2c receptors, followed by an anhedonic- and depressive-like state, in GluN2D KO mice. The GluN2D subunit of the NMDA receptor appears to be important for the recognition of individuals and development of normal emotionality in mice. 5-HT 2C receptor antagonism may be a therapeutic target for treating social stress-induced anhedonia. This article is part of the Special Issue entitled 'Ionotropic glutamate receptors'. Copyright © 2016 Elsevier Ltd. All rights reserved.

A novel 5HT3 antagonist 4i (N-(3-chloro-2-methylphenyl)quinoxalin-2-carboxamide) prevents diabetes-induced depressive phenotypes in mice: Modulation of serotonergic system.

PubMed

Gupta, Deepali; Thangaraj, Devadoss; Radhakrishnan, Mahesh

2016-01-15

Despite the presence of a multitudinous pharmacotherapy, diabetes-induced depressive disorder remains undertreated. Evidence suggests that brain serotonergic deficits are associated with depressive-like behavior in diabetes and that 5HT3 receptor (5HT3R) antagonists have serotonergic facilitatory effects. This study examined the effects of a novel 5HT3R antagonist, 4i (N-(3-chloro-2-methylphenyl)quinoxalin-2-carboxamide), in diabetes-induced depressive phenotypes. Experimentally, (1) to evaluate the effects of 4i, mice with 8-weeks of diabetes (induced by streptozotocin, 200mg/kg, i.p.) were treated with vehicle, 4i (0.5 and 1mg/kg/day, i.p.), fluoxetine (10mg/kg/day, i.p.) for 4-weeks and subjected to neurobehavioral assays, followed by biochemical estimation of serotonin levels in midbrain, prefrontal-cortex and cerebellum. (2) To evaluate the role of 5HT3R in the postulated effect of 4i, diabetic mice were given 4i (1mg/kg/day, i.p.) after 1h of 1-(m-chlorophenyl)-biguanide (mCPBG, a 5HT3R agonist, 10mg/kg/day, i.p.) treatment and subjected to the same protocol. The results showed that diabetic mice exhibited a significant behavioral deficit, including depression-like behavior in forced swim test, anxiety-like in open field test and sociability deficits in social interaction test, along with a significant decrease in serotonin level in these brain regions. 4i (1mg/kg), similar to fluoxetine, prevented these behavioral abnormalities and normalized brain serotonin levels. 4i (0.5mg/kg) ameliorated only diabetes-induced depressive-like behavior and serotonin deficits, but not anxiety-like effects. mCPBG blunted 4i-mediated behavioral response and increase in brain serotonin levels. Altogether, this study suggests that 4i prevents diabetes-induced depressive phenotypes in mice, which may involve antagonism of 5HT3Rs and increase in serotonin levels in discrete brain regions. Copyright © 2015 Elsevier B.V. All rights reserved.

A chronic treatment with fluoxetine decreases 5-HT(1A) receptors labeling in mice selected as a genetic model of helplessness.

PubMed

Naudon, Laurent; El Yacoubi, Malika; Vaugeois, Jean-Marie; Leroux-Nicollet, Isabelle; Costentin, Jean

2002-05-17

Two lines of mice were bred for their opposite helpless behavior in the tail suspension test, i.e., helpless (HL) mice and non helpless (NHL) mice. The 5-HT(1A) receptor labeling was quantified by means of autoradiography with (3)H-8-OH-DPAT on brain sections from mice of these two lines. We observed a significantly higher level of (3)H-8-OH-DPAT binding sites density in HL mice comparatively to NHL mice, in the medial prefrontal, cingulate, motor and sensorial cortices, in several regions of the limbic system, such as CA3 field of hippocampus, dentate gyrus, medial and baso-medial amygdala, and in dorsal and median raphe nuclei. A chronic 21-day treatment with the antidepressant fluoxetine (10 mg/kg, i.p. daily) attenuated significantly the spontaneous helplessness in HL mice but did not alter the behavior of NHL mice. In the brain of HL mice chronically injected with fluoxetine, the elevated (3)H-8-OH-DPAT binding sites density was no longer observed after treatment in several regions, among which the raphe nuclei. Conversely, the antidepressant treatment did not modify the (3)H-8-OH-DPAT binding sites density in NHL mice. The variation of 5-HT(1A) receptors binding density in the HL mice in response to a chronic fluoxetine treatment parallels the attenuation of the spontaneous helplessness observed in the tail suspension test, and may underlie this behavior.

Important role of mucosal serotonin in colonic propulsion and peristaltic reflexes: in vitro analyses in mice lacking tryptophan hydroxylase 1

PubMed Central

Heredia, Dante J; Gershon, Michael D; Koh, Sang Don; Corrigan, Robert D; Okamoto, Takanubu; Smith, Terence K

2013-01-01

Although there is general agreement that mucosal 5-hydroxytryptamine (5-HT) can initiate peristaltic reflexes in the colon, recent studies have differed as to whether or not the role of mucosal 5-HT is critical. We therefore tested the hypothesis that the secretion of 5-HT from mucosal enterochromaffin (EC) cells is essential for the manifestation of murine colonic peristaltic reflexes. To do so, we analysed the mechanisms underlying faecal pellet propulsion in isolated colons of mice lacking tryptophan hydroxylase 1 (Tph1−/− mice), which is the rate-limiting enzyme in the biosynthesis of mucosal but not neuronal 5-HT. We used video analysis of faecal pellet propulsion, tension transducers to record colonic migrating motor complexes (CMMCs) and intracellular microelectrodes to record circular muscle activity occurring spontaneously or following intraluminal distension. When compared with control (Tph1+/+) mice, Tph1−/− animals exhibited: (1) an elongated colon; (2) larger faecal pellets; (3) orthograde propulsion followed by retropulsion (not observed in Tph1+/+ colon); (4) slower in vitro propulsion of larger faecal pellets (28% of Tph1+/+); (5) CMMCs that infrequently propagated in an oral to anal direction because of impaired descending inhibition; (6) reduced CMMCs and inhibitory responses to intraluminal balloon distension; (7) an absence of reflex activity in response to mucosal stimulation. In addition, (8) thin pellets that propagated along the control colon failed to do so in Tph1−/− colon; and (9) the 5-HT3 receptor antagonist ondansetron, which reduced CMMCs and blocked their propagation in Tph1+/+ mice, failed to alter CMMCs in Tph1−/− animals. Our observations suggest that mucosal 5-HT is essential for reflexes driven by mucosal stimulation and is also important for normal propagation of CMMCs and propulsion of pellets in the isolated colon. PMID:24127620

Ethanol induced adaptations in 5-HT2c receptor signaling in the bed nucleus of stria terminalis: Implications for anxiety during ethanol withdrawal

PubMed Central

Marcinkiewcz, Catherine A.; Dorrier, Cayce E.; Lopez, Alberto J.; Kash, Thomas L.

2015-01-01

One of the hallmarks of alcohol dependence is the presence of a withdrawal syndrome during abstinence, which manifests as physical craving for alcohol accompanied by subjective feelings of anxiety. Using a model of chronic intermittent ethanol (CIE) vapor in mice, we investigated the role of serotonin2c signaling in the BNST as a neural substrate underlying ethanol-induced anxiety during withdrawal. Mice were subjected to a 5-day CIE regimen of 16 hours of ethanol vapor exposure followed by an 8 hour “withdrawal” period between exposures. After the 5th and final exposure, mice were withdrawn for 24 hours or 1 week before experiments began. Anxiety-like behavior was assessed in the social approach, light dark, and open field test with mice showing deficits in social, but not general anxiety-like behavior that was alleviated by pretreatment with the 5HT2c-R antagonist SB 242,084 (3 mg/kg, i.p.) 24 hours and 1 week post-CIE. Using immunohistochemistry and whole cell patch clamp electrophysiology, we also found that CIE increased FOS-IR and enhanced neuronal excitability in the ventral BNST (vBNST) 24 hrs into withdrawal in a 5HT2c-R dependent manner. This enhanced excitability persisted for 1 week post-CIE. We also found that mCPP, a 5HT2c/b agonist, induced a more robust depolarization in cells of the vBNST in CIE mice, confirming that 5HT2c-R signaling is upregulated in the vBNST following CIE. Taken together, these results suggest that CIE upregulates 5HT2c-R signaling in the vBNST, leading to increased excitability. This enhanced excitability of the vBNST may drive increased anxiety-like behavior during ethanol withdrawal. PMID:25229718

Serotonin signaling is crucial in the induction of PUVA-induced systemic suppression of delayed type hypersensitivity but not local apoptosis or inflammation of the skin

PubMed Central

Wolf, Peter; Byrne, Scott N.; Limon-Flores, Alberto Y.; Hoefler, Gerald; Ullrich, Stephen E.

2016-01-01

Psoralen and UVA (PUVA) has immunosuppressive and proapoptotic effects, which are thought to be responsible alone or in combination for its therapeutic efficacy. However, the molecular mechanism by which PUVA mediates its effects are not well understood. Activation of the serotonin (5-hydroxytryptamine, 5-HT) pathway has been suggested to be involved in the modulation of T cell responses and found to mediate UVB-induced immune suppression. In particular, the activation of the 5-HT2A receptor has been proposed as one mechanism responsible for UV-induced immune suppression. We therefore hypothesized that 5-HT may play a role in PUVA-induced effects. The model of systemic suppression of delayed-type hypersensitivity (DTH) to Candida albicans was used to study immune function after exposure of C3H and KITW-Sh/W-Sh mice to a minimal inflammatory dose of topical PUVA. The intraperitoneal injection of the 5-HT2 receptor antagonist ketanserin or cyproheptadine or an anti-5-HT antibody immediately before PUVA exposure entirely abrogated suppression of DTH but had no significant effect on inflammation, as measured by swelling and cellular infiltration of the skin, and apoptosis as determined by the number of sunburn cells in C3H mice. Importantly, the systemic injection of 5-HT recapitulated PUVA immune suppression of DTH but did not induce inflammation or apoptosis in the skin. KITW-Sh/W-Sh mice (exhibiting myelopoietic abnormalities, including lack of 5-HT-containing mast cells) were resistant to PUVA-induced suppression of DTH but not local skin swelling. Thus, this points towards a crucial role of 5-HT signaling in PUVA-induced immune suppression but not inflammation or apoptosis in situ in the skin. PMID:26914366

Focused cerebellar laser light induced hyperthermia improves symptoms and pathology of polyglutamine disease SCA1 in a mouse model.

PubMed

Hearst, Scoty M; Shao, Qingmei; Lopez, Mariper; Raucher, Drazen; Vig, Parminder J S

2014-10-01

Spinocerebellar ataxia 1 (SCA1) results from pathologic glutamine expansion in the ataxin-1 protein (ATXN1). This misfolded ATXN1 causes severe Purkinje cell (PC) loss and cerebellar ataxia in both humans and mice with the SCA1 disease. The molecular chaperone heat-shock proteins (HSPs) are known to modulate polyglutamine protein aggregation and are neuroprotective. Since HSPs are induced under stress, we explored the effects of focused laser light induced hyperthermia (HT) on HSP-mediated protection against ATXN1 toxicity. We first tested the effects of HT in a cell culture model and found that HT induced Hsp70 and increased its localization to nuclear inclusions in HeLa cells expressing GFP-ATXN1[82Q]. HT treatment decreased ATXN1 aggregation by making GFP-ATXN1[82Q] inclusions smaller and more numerous compared to non-treated cells. Further, we tested our HT approach in vivo using a transgenic (Tg) mouse model of SCA1. We found that our laser method increased cerebellar temperature from 38 to 40 °C without causing any neuronal damage or inflammatory response. Interestingly, mild cerebellar HT stimulated the production of Hsp70 to a significant level. Furthermore, multiple exposure of focused cerebellar laser light induced HT to heterozygous SCA1 transgenic (Tg) mice significantly suppressed the SCA1 phenotype as compared to sham-treated control animals. Moreover, in treated SCA1 Tg mice, the levels of PC calcium signaling/buffering protein calbindin-D28k markedly increased followed by a reduction in PC neurodegenerative morphology. Taken together, our data suggest that laser light induced HT is a novel non-invasive approach to treat SCA1 and maybe other polyglutamine disorders.

Effects of prenatal stress and monoaminergic perturbations on the expression of serotonin 5-HT₄ and adrenergic β₂ receptors in the embryonic mouse telencephalon.

PubMed

Chen, Angela; Kelley, Lauren D S; Janušonis, Skirmantas

2012-06-12

The serotonin 5-HT(4) receptor (5-HT(4)R) is coded by a complex gene that produces four mRNA splice variants in mice (5-HT(4(a))R, 5-HT(4(b))R, 5-HT(4(e))R, 5-HT(4(f))R). This receptor has highly dynamic expression in brain development and its splice variants differ in their developmental trajectories. Since 5-HT(4)Rs are important in forebrain function (including forebrain control of serotonergic activity in the brainstem), we investigated the susceptibility of 5-HT(4)R expression in the mouse embryonic telencephalon to prenatal maternal stress and altered serotonin (5-hydroxytryptamine, 5-HT) levels. Because the gene coding the adrenergic β(2) receptor (β(2)AR) is embedded in the 5-HT(4)R gene, we also investigated whether 5-HT(4)R mRNA levels were modulated by selective β(2)AR agents. Timed-pregnant C57BL/6 mice were treated beginning at embryonic day (E) 14 and quantitative reverse-transcription polymerase chain reaction (qRT-PCR) was used to assess the mRNA levels of all 5-HT(4)R splice variants and β(2)AR in the embryonic telencephalon at E17. Maternal prenatal stress and 5-HT depletion with pCPA, a tryptophan hydroxylase inhibitor, reduced the levels of the 5-HT(4(b))R splice variant. Terbutaline (a selective β(2)AR agonist) and ICI 118,551 (a selective β(2)AR antagonist) had no effect on β(2)AR and 5-HT(4)R mRNA levels. These results show that prenatal stress and reduced 5-HT levels can alter 5-HT(4)R expression in the developing forebrain and that some 5-HT(4)R splice variants may be more susceptible than others. Copyright © 2012 Elsevier B.V. All rights reserved.

An interplay between the serotonin transporter (SERT) and 5-HT receptors controls stimulus-secretion coupling in sympathoadrenal chromaffin cells.

PubMed

Brindley, Rebecca L; Bauer, Mary Beth; Blakely, Randy D; Currie, Kevin P M

2016-11-01

Adrenal chromaffin cells (ACCs), the neuroendocrine arm of the sympathetic nervous system, secrete catecholamines to mediate the physiological response to stress. Although ACCs do not synthesize 5-HT, they express the serotonin transporter (SERT). Genetic variations in SERT are linked to several CNS disorders but the role(s) of SERT/5-HT in ACCs has remained unclear. Adrenal glands from wild-type mice contained 5-HT at ≈ 750 fold lower abundance than adrenaline, and in SERT(-/-) mice this was reduced by ≈80% with no change in catecholamines. Carbon fibre amperometry showed that SERT modulated the ability of 5-HT1A receptors to inhibit exocytosis. 5-HT reduced the number of amperometric spikes (vesicular fusion events) evoked by KCl in SERT(-/-) cells and wild-type cells treated with escitalopram, a SERT antagonist. The 5-HT1A receptor antagonist WAY100635 blocked the inhibition by 5-HT which was mimicked by the 5-HT1A agonist 8-OH-DPAT but not the 5-HT1B agonist CP93129. There was no effect on voltage-gated Ca(2+) channels, K(+) channels, or intracellular [Ca(2+)] handling, showing the 5-HT receptors recruit an atypical inhibitory mechanism. Spike charge and kinetics were not altered by 5-HT receptors but were reduced in SERT(-/-) cells compared to wild-type cells. Our data reveal a novel role for SERT and suggest that adrenal chromaffin cells might be a previously unrecognized hub for serotonergic control of the sympathetic stress response. Copyright © 2016 Elsevier Ltd. All rights reserved.

5-HT2A receptors control body temperature in mice during LPS-induced inflammation via regulation of NO production.

PubMed

Voronova, Irina P; Khramova, Galina M; Kulikova, Elizabeth A; Petrovskii, Dmitrii V; Bazovkina, Daria V; Kulikov, Alexander V

2016-01-01

G protein-coupled 5-HT2A receptors are involved in the regulation of numerous normal and pathological physiological functions. At the same time, its involvement in the regulation of body temperature (Tb) in normal conditions is obscure. Here we study the effect of the 5-HT2A receptor activation or blockade on Tb in sick animals. The experiments were carried out on adult C57BL/6 mouse males. Systemic inflammation and sickness were produced by lipopolysaccharide (LPS, 0.1mg/kg, ip), while the 5-HT2A receptor was stimulated or blocked through the administration of the receptor agonist DOI or antagonist ketanserin (1mg/kg), respectively. LPS, DOI or ketanserin alone produced no effect on Tb. However, administration of LPS together with a peripheral or central ketanserin injection reduced Tb (32.2°C). Ketanserin reversed the LPS-induced expression of inducible NO synthase in the brain. Consequently, an involvement of NO in the mechanism of the hypothermic effect of ketanserin in sick mice was hypothesized. Administration of LPS together with NO synthase inhibitor, l-nitro-arginine methyl ester (60mg/kg, ip) resulted in deep (28.5°C) and prolonged (8h) hypothermia, while administration of l-nitro-arginine methyl ester alone produced no effect on Tb. Thus, 5-HT2A receptors play a key role in Tb control in sick mice. Blockade of this GPCR produces hypothermia in mice with systemic inflammation via attenuation of LPS-induced NO production. These results indicate an unexpected role of 5-HT2A receptors in inflammation and NO production and have a considerable biological impact on understanding the mechanism of animal adaptation to pathogens and parasites. Moreover, adverse side effects of 5-HT2A receptor antagonists in patients with inflammation may be expected. Copyright © 2015 Elsevier Ltd. All rights reserved.

A pharmacological evidence of positive association between mouse intermale aggression and brain serotonin metabolism.

PubMed

Kulikov, A V; Osipova, D V; Naumenko, V S; Terenina, E; Mormède, P; Popova, N K

2012-07-15

The neurotransmitter serotonin (5-HT) is involved in the regulation of mouse intermale aggression. Previously, it was shown that intensity of mouse intermale aggression was positively associated with activity of the key enzyme of 5-HT synthesis - tryptophan hydroxylase 2 (TPH2) in mouse brain. The aim of the present study was to investigate the effect of pharmacological activation or inhibition of 5-HT synthesis in the brain on intermale aggression in two mouse strains differing in the TPH2 activity: C57BL/6J (B6, high TPH2 activity, high aggressiveness) and CC57BR/Mv (BR, low TPH2 activity, low aggressiveness). Administration of 5-HT precursor L-tryptophan (300 mg/kg, i.p.) to BR mice significantly increased the 5-HT and 5-hydroxyindoleacetic acid (5-HIAA) levels in the midbrain as well as the number of attacks and their duration in the resident-intruder test. And vice versa, administration of TPH2 inhibitor p-chlorophenylalanine (pCPA) (300 mg/kg, i.p., for 3 consecutive days) to B6 mice dramatically reduced the 5-HT and 5-HIAA contents in brain structures and attenuated the frequency and the duration of aggressive attacks. At the same time, L-tryptophan or pCPA did not influence the percentage of aggressive mice and the attack latency reflecting the threshold of aggressive reaction. This result indicated that the intensity of intermale aggression, but not the threshold of aggressive reaction is positively dependent on 5-HT metabolism in mouse brain. Copyright © 2012 Elsevier B.V. All rights reserved.

miR-29a-3p/T-bet Regulatory Circuit Is Altered in T Cells of Patients With Hashimoto's Thyroiditis.

PubMed

Tokić, Stana; Štefanić, Mario; Glavaš-Obrovac, Ljubica; Kishore, Amit; Navratilova, Zdenka; Petrek, Martin

2018-01-01

Hashimoto's thyroiditis (HT) is a common autoimmune thyroid disorder that frequently evolves from asymptomatic, T-cell mediated chronic inflammation toward overt hypothyroidism. Previously, we have demonstrated a role for T-bet, a T helper 1/CD8 + T cell transcription factor (TF), and FoxP3, a regulatory T cell TF, in disease progression and severity, but the basis behind their altered mRNA expression remains unknown. In this study, we aimed to leverage the role for microRNAs, representing negative transcriptional regulators, across the spectrum of HT clinical presentations using the same, well-characterized RNA sample cohort. Ten hypothyroid, untreated patients (hypoHT), 10 hypothyroid cases rendered euthyroid by l-thyroxine therapy (substHT), 11 spontaneously euthyroid HT subjects (euHT), and 10 healthy controls (ctrl) were probed for three candidate immunoregulatory miRNA (miR-9-5p, miR-29a-3p, and miR-210-3p) using quantitative real-time PCR measurements. Data were normalized to U6snRNA and fold difference in expression calculated by the efficiency corrected 2 -ΔΔCt model. Compared to healthy controls, peripheral blood (PB) T cells of HT patients exhibited significantly diminished miR-29a-3p expression levels [median expression levels (IQR), HT vs CTRL, 0.62 (0.44-1.01) vs 1.373 (0.63-2.7), P  = 0.046], and a similar, but not significant decline in miR-210-3p abundance [HT vs CTRL, 0.64 (0.39-1.31) vs 1.2 (0.5-2.56), P  = 0.24, Wilcoxon test]. A significant inverse correlation was observed between the two differentially expressed transcripts, T-bet mRNA and miR-29a-3p. Moreover, altered miR-29a-3p/T-bet expression in T cells of untreated HT patients was related to low serum FT4, high serum thyrotropin, and decreased thyroid volumes. Of note, miR-210-3p expression was positively correlated to HIF1α, and inversely to FoxP3 mRNA levels, but no evidence of differential expression for any of these miRNA-mRNA pairs was observed. Finally, miR-9-5p expression levels were no different in HT vs control comparisons, or related to clinicopathological features. T cell miR-29a-3p is downregulated in HT patients and associated with clinical and biochemical parameters of progressive thyroid injury, plausibly subsequent to altered control of T-bet expression in PB T cells. As such miR-29a-3p/T-bet axis should be further explored as a biomarker or as a plausible target for therapeutic interventions in HT.

Biological mechanisms associated with increased perseveration and hyperactivity in a genetic mouse model of neurodevelopmental disorder

PubMed Central

Trent, Simon; Dean, Rachel; Veit, Bonnie; Cassano, Tommaso; Bedse, Gaurav; Ojarikre, Obah A.; Humby, Trevor; Davies, William

2013-01-01

Summary Chromosomal deletions at Xp22.3 appear to influence vulnerability to the neurodevelopmental disorders attention deficit hyperactivity disorder (ADHD) and autism. 39,XY*O mice, which lack the murine orthologue of the Xp22.3 ADHD candidate gene STS (encoding steroid sulfatase), exhibit behavioural phenotypes relevant to such disorders (e.g. hyperactivity), elevated hippocampal serotonin (5-HT) levels, and reduced serum levels of dehydroepiandrosterone (DHEA). Here we initially show that 39,XY*O mice are also deficient for the recently-characterised murine orthologue of the Xp22.3 autism candidate gene ASMT (encoding acetylserotonin-O-methyltransferase). Subsequently, to specify potential behavioural correlates of elevated hippocampal 5-HT arising due to the genetic lesion, we compared 39,XY*O MF1 mice to 40,XY MF1 mice on behavioural tasks taxing hippocampal and/or 5-HT function (a ‘foraging’ task, an object-location task, and the 1-choice serial reaction time task of impulsivity). Although Sts/Asmt deficiency did not influence foraging behaviour, reactivity to familiar objects in novel locations, or ‘ability to wait’, it did result in markedly increased response rates; these rates correlated with hippocampal 5-HT levels and are likely to index behavioural perseveration, a frequent feature of neurodevelopmental disorders. Additionally, we show that whilst there was no systematic relationship between serum DHEA levels and hippocampal 5-HT levels across 39,XY*O and 40,XY mice, there was a significant inverse linear correlation between serum DHEA levels and activity. Our data suggest that deficiency for genes within Xp22.3 could influence core behavioural features of neurodevelopmental disorders via dissociable effects on hippocampal neurochemistry and steroid hormone levels, and that the mediating neurobiological mechanisms may be investigated in the 39,XY*O model. PMID:23276394

5-HT1A Receptors on Mature Dentate Gyrus Granule Cells are Critical for the Antidepressant Response

PubMed Central

Samuels, Benjamin Adam; Anacker, Christoph; Hu, Alice; Levinstein, Marjorie R.; Pickenhagen, Anouchka; Tsetsenis, Theodore; Madroñal, Noelia; Donaldson, Zoe R.; Drew, Liam John; Dranovsky, Alex; Gross, Cornelius T.; Tanaka, Kenji F.; Hen, René

2015-01-01

Selective serotonin reuptake inhibitors (SSRIs) are widely used antidepressants, but the mechanisms by which they influence behavior are only partially resolved. Adult hippocampal neurogenesis is necessary for some of the responses to SSRIs, but it is unknown whether the mature dentate gyrus granule cells (mature DG GCs) also contribute. We deleted Serotonin 1A receptor (5HT1AR; a receptor required for the SSRI response) specifically from DG GCs and found that the effects of the SSRI fluoxetine on behavior and the Hypothalamic-Pituitary-Adrenal (HPA) axis were abolished. By contrast, mice lacking 5HT1ARs only in young adult born granule cells (abGCs) showed normal fluoxetine responses. Importantly, 5HT1AR deficient mice engineered to express functional 5HT1ARs only in DG GCs responded to fluoxetine, indicating that 5HT1ARs in DG GCs are sufficient to mediate an antidepressant response. Taken together, these data indicate that both mature DG GCs and young abGCs must be engaged for an antidepressant response. PMID:26389840

Alterations in melatonin and 5-HT signalling in the colonic mucosa of mice with dextran-sodium sulfate-induced colitis.

PubMed

MacEachern, Sarah J; Keenan, Catherine M; Papakonstantinou, Evangelia; Sharkey, Keith A; Patel, Bhavik Anil

2018-05-01

Inflammatory bowel disease (IBD) is characterized by pain, bleeding, cramping and altered gastrointestinal (GI) function. Changes in mucosal 5-HT (serotonin) signalling occur in animal models of colitis and in humans suffering from IBD. Melatonin is co-released with 5-HT from the mucosa and has a wide variety of actions in the GI tract. Here, we examined how melatonin signalling is affected by colitis and determined how this relates to 5-HT signalling. Using electroanalytical approaches, we investigated how 5-HT release, reuptake and availability as well as melatonin availability are altered in dextran sodium sulfate (DSS)-induced colitis in mice. Studies were conducted to explore if melatonin treatment during active colitis could reduce the severity of colitis. We observed an increase in 5-HT and a decrease in melatonin availability in DSS-induced colitis. A significant reduction in 5-HT reuptake was observed in DSS-induced colitis animals. A reduction in the content of 5-HT was observed, but no difference in tryptophan levels were observed. A reduction in deoxycholic acid-stimulated 5-HT availability and a significant reduction in mechanically-stimulated 5-HT and melatonin availability were observed in DSS-induced colitis. Orally or rectally administered melatonin once colitis was established did not significantly suppress inflammation. Our data suggest that DSS-induced colitis results in a reduction in melatonin availability and an increase in 5-HT availability, due to a reduction/loss of tryptophan hydroxylase 1 enzyme, 5-HT content and 5-HT transporters. Mechanosensory release was more susceptible to inflammation when compared with chemosensory release. © 2018 The British Pharmacological Society.

Attenuation of hepatotoxicity and oxidative stress in diabetes STZ-induced type 1 by biotin in Swiss albino mice

PubMed Central

Aldahmash, Badr Abdullah; El-Nagar, Doaa Mohamed; Ibrahim, Khalid Elfakki

2015-01-01

Diabetes mellitus is one of the major health problems. This study was designed to investigate the effect of biotin to regulate blood glucose level, reduced toxicity and oxidative stress in liver of diabetic mice STZ-induced type 1. Male mice were divided into three groups, the first one served as the control group, the second and the third groups received single ip dose of 150 mg/kg of STZ, the second group served as the untreated diabetic group, the third group received daily oral dose of 15 mg/kg of biotin, livers and liver index showed insignificant difference among groups. Blood glucose level showed a significant decrease in treated diabetic mice compared to untreated diabetic mice. Biochemical analysis showed a significant decrease in liver enzymes AST and ALT compared to the control group. Histopathological examination showed severe changes in untreated diabetic liver tissue manifested by dilated portal vein, leukocytic infiltration, fatty degeneration and moderate to severe histopathological score, whereas, treated diabetic mice with biotin showed reduction in hepatotoxicity represented by appearance of relative healthy hepatocytes and normal histopathological score. Immunohistochemistry of acrolein showed intense immunoreactions in liver section of untreated diabetic mice and faint immunoreactions in treated diabetic mice with biotin as evidence to oxidative stress reduction. PMID:26981014

Time-dependent impact of glutamatergic modulators on the promnesiant effect of 5-HT6R blockade on mice recognition memory.

PubMed

Asselot, Rachel; Simon-O'Brien, Emmanuelle; Lebourgeois, Sophie; Nee, Gérald; Delaunay, Virgile; Duchatelle, Pascal; Bouet, Valentine; Dauphin, François

2017-04-01

Selective antagonists at serotonin 5-HT 6 receptors (5-HT 6 R) improve memory performance in rodents and are currently under clinical investigations. If blockade of 5-HT 6 R is known to increase glutamate release, only two studies have so far demonstrated an interaction between 5-HT 6 R and glutamate transmission, but both, using the non-competitive NMDA antagonist MK-801, insensitive to variations of glutamate concentrations. In a place recognition task, we investigated here in mice the role of glutamate transmission in the beneficial effects of 5-HT 6 R blockade (SB-271046). Through the use of increasing intervals (2, 4 and 6h) between acquisition and retrieval, we investigated the time-dependent impact of two different glutamatergic modulators. NMDAR-dependant glutamate transmission (NMDA Receptors) was either blocked by the competitive antagonist at NMDAR, CGS 19755, or potentiated by the glycine transporter type 1 (GlyT1) inhibitor, NFPS. Results showed that neither SB-271046, nor CGS 19755, nor NFPS, alter behavioural performances after short intervals, i.e. when control mice displayed significant memory performances (2h and 4h) (respectively 10, 3, and 0.625mg.kg -1 ). Conversely, with the 6h-interval, a situation in which spontaneous forgetting is observed in control mice, SB-271046 improved recognition memory performances. This beneficial effect was prevented when co-administered with either CGS 19755 or NFPS, which themselves had no effect. Interestingly, a dose-dependent effect was observed with NFPS, with promnesic effect observed at lower dose (0.156mg.kg -1 ) when administrated alone, whereas it did no modify promnesic effect of SB-271046. These results demonstrate that promnesiant effect induced by 5-HT 6 R blockade is sensitive to the competitive blockade of NMDAR and underline the need of a fine adjustment of the inhibition of GlyT1. Overall, our findings support the idea of a complex crosstalk between serotonergic and glutamatergic systems in the promnesic properties of 5-HT 6 R antagonists. Copyright © 2016 Elsevier Ltd. All rights reserved.

Do imipramine and dihydroergosine possess two components - one stimulating 5-HT sub 1 and the other inhibiting 5-HT sub 2 receptors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pericic, D.; Mueck-Seler, D.

1990-01-01

The mechanisms by which imipramine and dihydroergosine stimulate the 5-HT syndrome in rats and inhibit the head-twitch response in rats and mice were studied. Imipramine- and dihydroergosine-included stimulation of the 5-HT syndrome was inhibited stereoselectively by propranolol, a high affinity ligand for 5-HT{sub 1} receptor sites, but not by ritanserin, a specific 5-HT{sub 2} receptor antagonist. (-) -Propranolol potentiated the inhibitory effect of imipramine, but not of dihydroergosine on the head-twitch response, while ritanserin was without effect. As expected, 8-OH-DPAT, a selective 5-HT{sub 1A} receptor agonist, stimulated, and 5-HT{sub 1B} agonists CGS 12066B and 1-(trifluoromethylphenyl) piperazine (TFMPP) failed to stimulatemore » the 5-HT syndrome induced in rats by pargyline and 5-HTP administration. A higher dose of ritanserin inhibited the syndrome. While 8-OH-DPAT alone produced all behavioral components of the 5-HT syndrome, dihydroergosine or imipramine alone even at very high doses never produced tremor or a more intensive forepaw padding as seen when these drugs were given in combination with pargyline and 5-HTP. A single administration of (-)-propranolol also inhibited the head-twitch response. This effect lasted in mice longer that after ritanserin administration. In in vitro experiments dihydroergosine expressed approximately twenty-fold higher affinity for {sup 3}H-ketanserin binding sites than imipramine.« less

Regulator of G-protein signaling 6 (RGS6) promotes anxiety and depression by attenuating serotonin-mediated activation of the 5-HT1A receptor-adenylyl cyclase axis

PubMed Central

Stewart, Adele; Maity, Biswanath; Wunsch, Amanda M.; Meng, Fantao; Wu, Qi; Wemmie, John A.; Fisher, Rory A.

2014-01-01

Targeting serotonin (5-HT) bioavailability with selective 5-HT reuptake inhibitors (SSRIs) remains the most widely used treatment for mood disorders. However, their limited efficacy, delayed onset of action, and side effects restrict their clinical utility. Endogenous regulator of G-protein signaling (RGS) proteins have been implicated as key inhibitors of 5-HT1ARs, whose activation is believed to underlie the beneficial effects of SSRIs, but the identity of the specific RGS proteins involved remains unknown. We identify RGS6 as the critical negative regulator of 5-HT1AR-dependent antidepressant actions. RGS6 is enriched in hippocampal and cortical neurons, 5-HT1AR-expressing cells implicated in mood disorders. RGS6−/− mice exhibit spontaneous anxiolytic and antidepressant behavior rapidly and completely reversibly by 5-HT1AR blockade. Effects of the SSRI fluvoxamine and 5-HT1AR agonist 8-OH-DPAT were also potentiated in RGS6+/− mice. The phenotype of RGS6−/− mice was associated with decreased CREB phosphorylation in the hippocampus and cortex, implicating enhanced Gαi-dependent adenylyl cyclase inhibition as a possible causative factor in the behavior observed in RGS6−/− animals. Our results demonstrate that by inhibiting serotonergic innervation of the cortical-limbic neuronal circuit, RGS6 exerts powerful anxiogenic and prodepressant actions. These findings indicate that RGS6 inhibition may represent a viable means to treat mood disorders or enhance the efficacy of serotonergic agents.—Stewart, A., Maity, B., Wunsch, A. M., Meng, F., Wu, Q., Wemmie, J. A., Fisher, R. A. Regulator of G-protein signaling 6 (RGS6) promotes anxiety and depression by attenuating serotonin-mediated activation of the 5-HT1A receptor-adenylyl cyclase axis. PMID:24421401

Serotonin 5-HT2C receptor-mediated inhibition of the M-current in hypothalamic POMC neurons.

PubMed

Roepke, T A; Smith, A W; Rønnekleiv, O K; Kelly, M J

2012-06-01

Hypothalamic proopiomelanocortin (POMC) neurons are controlled by many central signals, including serotonin. Serotonin increases POMC activity and reduces feeding behavior via serotonion [5-hydroxytryptamine (5-HT)] receptors by modulating K(+) currents. A potential K(+) current is the M-current, a noninactivating, subthreshold outward K(+) current. Previously, we found that M-current activity was highly reduced in fasted vs. fed states in neuropeptide Y neurons. Because POMC neurons also respond to energy states, we hypothesized that fasting may alter the M-current and/or its modulation by serotonergic input to POMC neurons. Using visualized-patch recording in neurons from fed male enhanced green fluorescent protein-POMC transgenic mice, we established that POMC neurons expressed a robust M-current (102.1 ± 6.7 pA) that was antagonized by the selective KCNQ channel blocker XE-991 (40 μM). However, the XE-991-sensitive current in POMC neurons did not differ between fed and fasted states. To determine if serotonin suppresses the M-current via the 5-HT(2C) receptor, we examined the effects of the 5-HT(2A)/5-HT(2C) receptor agonist 2,5-dimethoxy-4-iodoamphetamine (DOI) on the M-current. Indeed, DOI attenuated the M-current by 34.5 ± 6.9% and 42.0 ± 5.3% in POMC neurons from fed and fasted male mice, respectively. In addition, the 5-HT(1B)/5-HT(2C) receptor agonist m-chlorophenylpiperazine attenuated the M-current by 42.4 ± 5.4% in POMC neurons from fed male mice. Moreover, the selective 5-HT(2C) receptor antagonist RS-102221 abrogated the actions of DOI in suppressing the M-current. Collectively, these data suggest that although M-current expression does not differ between fed and fasted states in POMC neurons, serotonin inhibits the M-current via activation of 5-HT(2C) receptors to increase POMC neuronal excitability and, subsequently, reduce food intake.

Relations between open-field, elevated plus-maze, and emergence tests in C57BL/6J and BALB/c mice injected with GABA- and 5HT-anxiolytic agents.

PubMed

Lalonde, Robert; Strazielle, Catherine

2010-06-01

Two 5HT(1A) receptor agonists and chlordiazepoxide were examined in open-field, elevated plus maze, and emergence tests. At doses with no effect in the open-field, chlordiazepoxide increased open and open/total arm visits as well as open arm duration in the elevated plus maze, whereas 5HT(1A) receptor agonists showed an anxiolytic response on a single measure. The anxiolytic action of chlordiazepoxide was limited to the less active BALB/c strain. Unlike the 5HT(1A) receptor agonists, chlordiazepoxide was also anxiolytic in the emergence test, once again only in BALB/c and not C57BL/6J mice. Significant correlations were found between emergence latencies and specific indicators of anxiety in the elevated plus-maze in chlordiazepoxide-treated but not in mice treated with buspirone and 8-OH-DPAT. These results indicate that elevated plus-maze and emergence tests depend on benzodiazepine receptors. In contrast, 5HT(1A) receptor agonists were ineffective in the emergence test and no correlation was found between emergence latencies and specific indicators of anxiety in the elevated plus-maze. Though superficially similar, the emergence test seems to tap into a partially separate facet of anxiety.

Protective effects of hydroxytyrosol on gentamicin induced nephrotoxicity in mice.

PubMed

Chashmi, Nooshin Ahmadian; Emadi, Sarvenaz; Khastar, Hossein

2017-01-22

Gentamicin (GM) is an effective and common antibiotic against severe gram-negative infections. However, its nephrotoxic action has limited the extent of its use. The aim of this study was to investigate the protective effects of hydroxytyrosol (HT) on gentamicin induced nephrotoxicity in mice. Male mice (n = 27) were randomly assigned to three groups: (1) Sham, (2) GM (100 mg/kg for 7 days) (3) GM + HT (2 mg/kg BW; gastric gavages, for 7 days). 24-h urine samples were collected on day 8 and then animal were anesthetized. The blood and kidney tissue samples were collected. Gentamicin led to increase in plasma BUN and creatinine, fractional excretion of sodium and potassium and decrease in creatinine clearance and urine flow rate. SOD and GSH levels were reduced and MDA was increased in the GM group compared with the sham group. In GM + HT group, plasma BUN and creatinine, fractional excretion of Na, creatinine clearance and urine flow rate were decreased in contrast to GM group. Increase in SOD and GSH activity and decrease in MDA compared to GM group were seen. Findings suggest that HT partly protected the kidneys from gentamicin induced nephrotoxicity and it is partly due to antioxidant effect of HT. Copyright © 2016 Elsevier Inc. All rights reserved.

Serotonin receptor 5-HT5A in rat hippocampus decrease by leptin treatment.

PubMed

García-Alcocer, Guadalupe; Rodríguez, Angelina; Moreno-Layseca, Paulina; Berumen, Laura C; Escobar, Jesica; Miledi, Ricardo

2010-12-17

5-Hydroxytryptamine (5-HT) is involved in a variety of different physiological processes and behaviors through the activation of equally diverse receptors subtypes. In this work we studied the changes on the expression of 5-HT(5A) receptors in rat hippocampus induced by leptin, an adipocyte-derived hormone that has been reported to participate in the modulation of food intake and in adult hippocampal neurogenesis. To study the effect of leptin on the 5-HT(5A) receptor gene expression a qRT-PCR was used and the distribution of those receptors in the hippocampus was visualized by immunohistochemistry. Rats were separated in four groups: control (untreated rats), leptin-treated, serotonin-treated and leptin+serotonin treated. The results showed that even though the 5-HT(5A) gene expression did not change in the hippocampus of any of the treated groups, in the rats treated with leptin and serotonin, the specific immunostaining for the 5-HT(5A) serotonin receptor decreased significantly in the dentate gyrus. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

Cannabidiol improves brain and liver function in a fulminant hepatic failure-induced model of hepatic encephalopathy in mice

PubMed Central

Avraham, Y; Grigoriadis, NC; Poutahidis, T; Vorobiev, L; Magen, I; Ilan, Y; Mechoulam, R; Berry, EM

2011-01-01

BACKGROUND AND PURPOSE Hepatic encephalopathy is a neuropsychiatric disorder of complex pathogenesis caused by acute or chronic liver failure. We investigated the effects of cannabidiol, a non-psychoactive constituent of Cannabis sativa with anti-inflammatory properties that activates the 5-hydroxytryptamine receptor 5-HT1A, on brain and liver functions in a model of hepatic encephalopathy associated with fulminant hepatic failure induced in mice by thioacetamide. EXPERIMENTAL APPROACH Female Sabra mice were injected with either saline or thioacetamide and were treated with either vehicle or cannabidiol. Neurological and motor functions were evaluated 2 and 3 days, respectively, after induction of hepatic failure, after which brains and livers were removed for histopathological analysis and blood was drawn for analysis of plasma liver enzymes. In a separate group of animals, cognitive function was tested after 8 days and brain 5-HT levels were measured 12 days after induction of hepatic failure. KEY RESULTS Neurological and cognitive functions were severely impaired in thioacetamide-treated mice and were restored by cannabidiol. Similarly, decreased motor activity in thioacetamide-treated mice was partially restored by cannabidiol. Increased plasma levels of ammonia, bilirubin and liver enzymes, as well as enhanced 5-HT levels in thioacetamide-treated mice were normalized following cannabidiol administration. Likewise, astrogliosis in the brains of thioacetamide-treated mice was moderated after cannabidiol treatment. CONCLUSIONS AND IMPLICATIONS Cannabidiol restores liver function, normalizes 5-HT levels and improves brain pathology in accordance with normalization of brain function. Therefore, the effects of cannabidiol may result from a combination of its actions in the liver and brain. PMID:21182490

Cannabidiol improves brain and liver function in a fulminant hepatic failure-induced model of hepatic encephalopathy in mice.

PubMed

Avraham, Y; Grigoriadis, Nc; Poutahidis, T; Vorobiev, L; Magen, I; Ilan, Y; Mechoulam, R; Berry, Em

2011-04-01

Hepatic encephalopathy is a neuropsychiatric disorder of complex pathogenesis caused by acute or chronic liver failure. We investigated the effects of cannabidiol, a non-psychoactive constituent of Cannabis sativa with anti-inflammatory properties that activates the 5-hydroxytryptamine receptor 5-HT(1A) , on brain and liver functions in a model of hepatic encephalopathy associated with fulminant hepatic failure induced in mice by thioacetamide. Female Sabra mice were injected with either saline or thioacetamide and were treated with either vehicle or cannabidiol. Neurological and motor functions were evaluated 2 and 3 days, respectively, after induction of hepatic failure, after which brains and livers were removed for histopathological analysis and blood was drawn for analysis of plasma liver enzymes. In a separate group of animals, cognitive function was tested after 8 days and brain 5-HT levels were measured 12 days after induction of hepatic failure. Neurological and cognitive functions were severely impaired in thioacetamide-treated mice and were restored by cannabidiol. Similarly, decreased motor activity in thioacetamide-treated mice was partially restored by cannabidiol. Increased plasma levels of ammonia, bilirubin and liver enzymes, as well as enhanced 5-HT levels in thioacetamide-treated mice were normalized following cannabidiol administration. Likewise, astrogliosis in the brains of thioacetamide-treated mice was moderated after cannabidiol treatment. Cannabidiol restores liver function, normalizes 5-HT levels and improves brain pathology in accordance with normalization of brain function. Therefore, the effects of cannabidiol may result from a combination of its actions in the liver and brain. © 2011 The Authors. British Journal of Pharmacology © 2011 The British Pharmacological Society.

Neuropeptide AF induces anxiety-like and antidepressant-like behavior in mice.

PubMed

Palotai, Miklós; Telegdy, Gyula; Tanaka, Masaru; Bagosi, Zsolt; Jászberényi, Miklós

2014-11-01

Little is known about the action of neuropeptide AF (NPAF) on anxiety and depression. Only our previous study provides evidence that NPAF induces anxiety-like behavior in rats. Therefore, the aim of the present study was to investigate the action of NPAF on depression-like behavior and the underlying neurotransmissions in mice. In order to determine whether there are species differences between rats and mice, we have investigated the action of NPAF on anxiety-like behavior in mice as well. A modified forced swimming test (mFST) and an elevated plus maze test (EPMT) were used to investigate the depression and anxiety-related behaviors, respectively. Mice were treated with NPAF 30min prior to the tests. In the mFST, the animals were pretreated with a non-selective muscarinic acetylcholine receptor antagonist, atropine, a non-selective 5-HT2 serotonergic receptor antagonist, cyproheptadine, a mixed 5-HT1/5-HT2 serotonergic receptor antagonist, methysergide, a D2/D3/D4 dopamine receptor antagonist, haloperidol, a α1/α2β-adrenergic receptor antagonist, prazosin or a non-selective β-adrenergic receptor antagonist, propranolol 30min before the NPAF administration. In the mFST, NPAF decreased the immobility time and increased the climbing and swimming times. This action was reversed completely by methysergide and partially by atropine, whereas cyproheptadine, haloperidol, prazosin and propranolol were ineffective. In the EPMT, NPAF decreased the time spent in the arms (open/open+closed). Our results demonstrate that NPAF induces anti-depressant-like behavior in mice, which is mediated, at least in part, through 5HT2-serotonergic and muscarinic cholinergic neurotransmissions. In addition, the NPAF-induced anxiety is species-independent, since it develops also in mice. Copyright © 2014 Elsevier B.V. All rights reserved.

Vulnerability to mild predator stress in serotonin transporter knockout mice.

PubMed

Adamec, Robert; Burton, Paul; Blundell, Jacqueline; Murphy, Dennis L; Holmes, Andrew

2006-06-03

Effect of predator stress on rat and mouse anxiety-like behavior may model aspects of post traumatic stress disorder (PTSD). A single cat exposure of wild type (C57, CFW) mice can produce lasting anxiety-like effects in the elevated plus maze, light/dark box tests and startle. In addition, female but not male C57 mice are made more anxious in the plus maze by exposure to predator odors alone, suggesting differential vulnerability to predator stressors of differing intensity. There is a link between genetic variation in the serotonin (5-HT) transporter (SERT) and anxiety in humans. This prompted the generation of SERT knockout mice [see Holmes A, Murphy DL, Crawley, JN. Biol Psychiatry 2003;54(10):953-9]. Present work used these mice to determine if there was a link between vulnerability to the anxiogenic effects of predator odors and abnormalities of 5-HT transmission induced by a life long reduction in 5-HT reuptake. Wild type (WT, C57 background), heterozygous (SERT +/-, HET) mice and homozygous knockout (SERT -/-, KO) were assigned to handled control groups or groups exposed for 10 min to a large testing room rich in cat odor. One week after handling or room exposure, anxiety testing took place in the dark phase of the light/dark cycle, in red light. Predator odor exposure was selectively anxiogenic in the plus maze and light/dark box tests in SERT -/- mice. Exposure to predator odor did not potentiate startle. Findings suggest a role for abnormalities in 5-HT transmission in vulnerability to some of the lasting anxiogenic effects of species relevant stressors and possibly in vulnerability to PTSD.

Effect of Agaricus blazei Murrill extract on HT-29 human colon cancer cells in SCID mice in vivo.

PubMed

Wu, Ming-Fang; Chen, Yung-Liang; Lee, Mei-Hui; Shih, Yung-Luen; Hsu, Yu-Ming; Tang, Ming-Chu; Lu, Hsu-Feng; Tang, Nou-Ying; Yang, Su-Tso; Chueh, Fu-Shin; Chung, Jing-Gung

2011-01-01

Agaricus blazei Murrill (ABM) popularly known as 'Cogumelo do Sol' in Brazil, or 'Himematsutake' in Japan, is a mushroom native to Brazil and widely cultivated in Japan for its medicinal uses and is now considered one of the most important edible and culinary-medicinal biotechnological species. This study is the first tumor growth model to evaluate the amelioratory effect of ABM extract using HT-29 human colon cancer cells in severe combined immunodeficiency (SCID) mice. Forty SCID mice were inoculated with HT-29 cells to induce tumor formation and were then divided into four groups. All the four groups (control, low, medium and high concentration treatment) of mice were separately orally administered 0 mg, 1.125 mg, 4.5 mg or 45 mg ABM extract daily. After six weeks of treatment, 8 out of the 40 mice had not survived including one mouse which scored +++ (tumor up to 15 mm diameter) and four mice which scored ++++ (tumor over 15 mm diameter) in the control group and three mice which scored ++++ on the low-dose ABM treatment. After high- or medium-dose treatment, all ten mice in each group survived. The oral administration of ABM does not prevent tumor growth, as shown by increased tumor mass, but compared with the control group, the tumor mass seems to grow more slowly depending on the ABM dose.

Modeling Early Cortical Serotonergic Deficits in Autism

PubMed Central

Boylan, Carolyn B.; Blue, Mary E.; Hohmann, Christine F.

2007-01-01

Autism is a developmental brain disorder characterized by deficits in social interaction, language and behavior. Brain imaging studies demonstrate increased cerebral cortical volumes and micro- and macroscopic neuroanatomic changes in children with this disorder. Alterations in forebrain serotonergic function may underlie the neuroanatomic and behavioral features of autism. Serotonin is involved in neuronal growth and plasticity and these actions are likely mediated via serotonergic and glutamatergic receptors. Few animal models of autism have been described that replicate both etiology and pathophysiology. We report here on a selective serotonin (5-HT) depletion model of this disorder in neonatal mice that mimics neurochemical and structural changes in cortex and, in addition, displays a behavioral phenotype consistent with autism. Newborn male and female mice were depleted of forebrain 5-HT with injections of the serotonergic neurotoxin, 5,7-dihydroxytryptamine (5,7-DHT), into the bilateral medial forebrain bundle (mfb). Behavioral testing of these animals as adults revealed alterations in social, sensory and stereotypic behaviors. Lesioned mice showed significantly increased cortical width. Serotonin immunocytochemistry showed a dramatic long-lasting depletion of 5-HT containing fibers in cerebral cortex until postnatal day (PND) 60. Autoradiographic binding to high affinity 5-HT transporters was significantly but transiently reduced in cerebral cortex of 5,7-DHT-depleted mice. AMPA glutamate receptor binding was decreased at PND 15. We hypothesize that increased cerebral cortical volume and sensorimotor, cognitive and social deficits observed in both 5-HT-depleted animals and in individuals with autism, may be the result of deficiencies in timely axonal pruning to key cerebral cortical areas. PMID:17034875

Modeling early cortical serotonergic deficits in autism.

PubMed

Boylan, Carolyn B; Blue, Mary E; Hohmann, Christine F

2007-01-10

Autism is a developmental brain disorder characterized by deficits in social interaction, language and behavior. Brain imaging studies demonstrate increased cerebral cortical volumes and micro- and macro-scopic neuroanatomic changes in children with this disorder. Alterations in forebrain serotonergic function may underlie the neuroanatomic and behavioral features of autism. Serotonin is involved in neuronal growth and plasticity and these actions are likely mediated via serotonergic and glutamatergic receptors. Few animal models of autism have been described that replicate both etiology and pathophysiology. We report here on a selective serotonin (5-HT) depletion model of this disorder in neonatal mice that mimics neurochemical and structural changes in cortex and, in addition, displays a behavioral phenotype consistent with autism. Newborn male and female mice were depleted of forebrain 5-HT with injections of the serotonergic neurotoxin, 5,7-dihydroxytryptamine (5,7-DHT), into the bilateral medial forebrain bundle (mfb). Behavioral testing of these animals as adults revealed alterations in social, sensory and stereotypic behaviors. Lesioned mice showed significantly increased cortical width. Serotonin immunocytochemistry showed a dramatic long-lasting depletion of 5-HT containing fibers in cerebral cortex until postnatal day (PND) 60. Autoradiographic binding to high affinity 5-HT transporters was significantly but transiently reduced in cerebral cortex of 5,7-DHT-depleted mice. AMPA glutamate receptor binding was decreased at PND 15. We hypothesize that increased cerebral cortical volume and sensorimotor, cognitive and social deficits observed in both 5-HT-depleted animals and in individuals with autism, may be the result of deficiencies in timely axonal pruning to key cerebral cortical areas.

Prevention of alcohol-heightened aggression by CRF-R1 antagonists in mice: critical role for DRN-PFC serotonin pathway.

PubMed

Quadros, Isabel M; Hwa, Lara S; Shimamoto, Akiko; Carlson, Julia; DeBold, Joseph F; Miczek, Klaus A

2014-11-01

Alcohol can escalate aggressive behavior in a significant subgroup of rodents, humans, and nonhuman primates. The present study investigated whether blockade of corticotropin-releasing factor receptor type 1 (CRF-R1) could prevent the emergence of alcohol-heightened aggression in mice. The serotonin (5-HT) pathway from the dorsal raphe nucleus (DRN) to the medial prefrontal cortex (mPFC) by CRF-R1 was investigated as a possible target for the prevention of alcohol-heightened aggressive behavior. Male CFW mice that reliably exhibited aggressive behaviors after consuming 1 g/kg of alcohol received systemic or intra-DRN administration of CRF-R1 antagonists, CP-154,526 or MTIP, before a confrontation with a male conspecific. Blockade of DRN CRF-R1 receptors with both antagonists significantly reduced only alcohol-heightened aggression, whereas systemic administration reduced both alcohol-heightened and species-typical aggression. Next, a 5-HT1A agonist, 8-OH-DPAT, was coadministered with CP-154,526 into the DRN to temporarily disrupt 5-HT activity. This manipulation abolished the antiaggressive effects of intra-DRN CP-154,526. In the mPFC, in vivo microdialysis revealed that extracellular 5-HT levels were increased in mice that consumed alcohol and were then injected with CP-154,526, both systemically or intra-DRN. Neither alcohol nor CP-154,526 alone affected 5-HT release in the mPFC. The present results suggest the DRN as a critical site for CRF-R1 to modulate alcohol-heightened aggression via action on the serotonergic DRN-PFC pathway.

Genistein, a dietary soy isoflavone, exerts antidepressant-like effects in mice: Involvement of serotonergic system.

PubMed

Hu, Pei; Ma, Li; Wang, Yan-Gui; Ye, Feng; Wang, Chuang; Zhou, Wen-Hua; Zhao, Xin

2017-09-01

Genistein, a principal isoflavone property of soybeans, possesses multiple pharmacological activities such as neuroprotection. Recently, it was reported that genistein exerted antidepressant-like effects in animal models, but the mechanism of action remains ambiguous. The purpose of this study was to investigate the antidepressant-like effect of genistein in mice and explore the underlying mechanism(s), using two mouse models of depression, i.e. forced swim test (FST) and tail suspension test (TST). Chronic, but not acute (single dose), genistein treatment (5, 15 or 45 mg/kg, p.o., once per day for three weeks) exerted dose-dependently antidepressant-like effect in mice, concomitant with escalated levels of brain monoamines and suppressed monoamine oxidase (MAO) activity. Chemical depletion of brain serotonin by PCPA abrogated the antidepressant-like action of genistein, but it was not the case for ablation of NA by DSP-4. Moreover, the anti-depression by genistein was preferentially counteracted by co-administration of 5-HT 1A receptor antagonist WAY-100635, suggesting a pivotal role for 5-HT system coupled with 5-HT 1A receptors in mediating such genistein anti-depression. This point was further validated by the fact that genistein action was potentiated by co-treatment with 8-OH-DPAT, a selective 5-HT 1A receptor agonist. Collectively, these findings confirm that chronic genistein administration to mice engenders antidepressant-like efficacy evidenced by lessened behavioral despair. Serotonergic system that preferentially couples with 5-HT 1A receptors may be critically responsible for the present genistein anti-depression. Copyright © 2017 Elsevier Ltd. All rights reserved.

5HTR3A-driven GFP labels immature olfactory sensory neurons.

PubMed

Finger, Thomas E; Bartel, Dianna L; Shultz, Nicole; Goodson, Noah B; Greer, Charles A

2017-05-01

The ionotropic serotonin receptor, 5-HT 3 , is expressed by many developing neurons within the central nervous system. Since the olfactory epithelium continues to generate new olfactory sensory neurons (OSNs) throughout life, we investigated the possibility that 5-HT 3 is expressed in the adult epithelium. Using a transgenic mouse in which the promoter for the 5-HT 3a subunit drives expression of green fluorescent protein (GFP), we assessed the expression of this marker in the olfactory epithelium of adult mice. Both the native 5-HT 3a mRNA and GFP are expressed within globose basal cells of the olfactory and vomeronasal epithelium in adult mice. Whereas the 5-HT 3a mRNA disappears relatively quickly after final cell division, the GFP label persists for about 5 days, thereby labeling immature OSNs in both the main olfactory system and vomeronasal organ. The GFP-labeled cells include both proliferative globose basal cells as well as immature OSNs exhibiting the hallmarks of ongoing differentiation including GAP43, PGP9.5, but the absence of olfactory marker protein. Some of the GFP-labeled OSNs show characteristics of more mature yet still developing OSNs including the presence of cilia extending from the apical knob and expression of NaV1.5, a component of the transduction cascade. These findings suggest that 5-HT 3a is indicative of a proliferative or developmental state, regardless of age, and that the 5-HT 3A GFP mice may prove useful for future studies of neurogenesis in the olfactory epithelium. J. Comp. Neurol. 525:1743-1755, 2017. © 2016 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Losartan Decreases Cardiac Muscle Fibrosis and Improves Cardiac Function in Dystrophin-Deficient Mdx Mice

PubMed Central

Spurney, Christopher F.; Sali, Arpana; Guerron, Alfredo D.; Iantorno, Micaela; Yu, Qing; Gordish-Dressman, Heather; Rayavarapu, Sree; van der Meulen, Jack; Hoffman, Eric P.; Nagaraju, Kanneboyina

2014-01-01

Recent studies showed that chronic administration of losartan, an angiotensin II type I receptor antagonist, improved skeletal muscle function in dystrophin-deficient mdx mice. In this study, C57BL/10ScSn-Dmdmdx/J female mice were either untreated or treated with losartan (n = 15) in the drinking water at a dose of 600 mg/L over a 6-month period. Cardiac function was assessed via in vivo high frequency echocardiography and skeletal muscle function was assessed using grip strength testing, Digiscan monitoring, Rotarod timing, and in vitro force testing. Fibrosis was assessed using picrosirius red staining and Image J analysis. Gene expression was evaluated using real-time polymerized chain reaction (RT-PCR). Percentage shortening fraction was significantly decreased in untreated (26.9% ± 3.5%) mice compared to losartan-treated (32.2% ± 4.2%; P < .01) mice. Systolic blood pressure was significantly reduced in losartan-treated mice (56 ± 6 vs 69 ± 7 mm Hg; P < .0005). Percentage cardiac fibrosis was significantly reduced in losartan-treated hearts (P < .05) along with diaphragm (P < .01), extensor digitorum longus (P < .05), and gastrocnemius (P < .05) muscles compared to untreated mdx mice. There were no significant differences in skeletal muscle function between treated and untreated groups. Chronic treatment with losartan decreases cardiac and skeletal muscle fibrosis and improves cardiac systolic function in dystrophin-deficient mdx mice. PMID:21304057

Effect of Peripheral 5-HT on Glucose and Lipid Metabolism in Wether Sheep

PubMed Central

Watanabe, Hitoshi; Saito, Ryo; Nakano, Tatsuya; Takahashi, Hideyuki; Takahashi, Yu; Sumiyoshi, Keisuke; Sato, Katsuyoshi; Chen, Xiangning; Okada, Natsumi; Iwasaki, Shunsuke; Harjanti, Dian W.; Sekiguchi, Natsumi; Sano, Hiroaki; Kitazawa, Haruki; Rose, Michael T.; Ohwada, Shyuichi; Watanabe, Kouichi; Aso, Hisashi

2014-01-01

In mice, peripheral 5-HT induces an increase in the plasma concentrations of glucose, insulin and bile acids, and a decrease in plasma triglyceride, NEFA and cholesterol concentrations. However, given the unique characteristics of the metabolism of ruminants relative to monogastric animals, the physiological role of peripheral 5-HT on glucose and lipid metabolism in sheep remains to be established. Therefore, in this study, we investigated the effect of 5-HT on the circulating concentrations of metabolites and insulin using five 5-HT receptor (5HTR) antagonists in sheep. After fasting for 24 h, sheep were intravenously injected with 5-HT, following which-, plasma glucose, insulin, triglyceride and NEFA concentrations were significantly elevated. In contrast, 5-HT did not affect the plasma cholesterol concentration, and it induced a decrease in bile acid concentrations. Increases in plasma glucose and insulin concentrations induced by 5-HT were attenuated by pre-treatment with Methysergide, a 5HTR 1, 2 and 7 antagonist. Additionally, decreased plasma bile acid concentrations induced by 5-HT were blocked by pre-treatment with Ketanserin, a 5HTR 2A antagonist. However, none of the 5HTR antagonists inhibited the increase in plasma triglyceride and NEFA levels induced by 5-HT. On the other hand, mRNA expressions of 5HTR1D and 1E were observed in the liver, pancreas and skeletal muscle. These results suggest that there are a number of differences in the physiological functions of peripheral 5-HT with respect to lipid metabolism between mice and sheep, though its effect on glucose metabolism appears to be similar between these species. PMID:24505376

Postnatal Day 2 to 11 Constitutes a 5-HT-Sensitive Period Impacting Adult mPFC Function

PubMed Central

Rebello, Tahilia J.; Yu, Qinghui; Goodfellow, Nathalie M.; Caffrey Cagliostro, Martha K.; Teissier, Anne; Morelli, Emanuela; Demireva, Elena Y.; Chemiakine, Alexei; Rosoklija, Gorazd B.; Dwork, Andrew J.; Lambe, Evelyn K.; Ansorge, Mark S.

2014-01-01

Early-life serotonin [5-hydroxytryptamine (5-HT)] signaling modulates brain development, which impacts adult behavior, but 5-HT-sensitive periods, neural substrates, and behavioral consequences remain poorly understood. Here we identify the period ranging from postnatal day 2 (P2) to P11 as 5-HT sensitive, with 5-HT transporter (5-HTT) blockade increasing anxiety- and depression-like behavior, and impairing fear extinction learning and memory in adult mice. Concomitantly, P2–P11 5-HTT blockade causes dendritic hypotrophy and reduced excitability of infralimbic (IL) cortex pyramidal neurons that normally promote fear extinction. By contrast, the neighboring prelimbic (PL) pyramidal neurons, which normally inhibit fear extinction, become more excitable. Excitotoxic IL but not PL lesions in adult control mice reproduce the anxiety-related phenotypes. These findings suggest that increased 5-HT signaling during P2–P11 alters adult mPFC function to increase anxiety and impair fear extinction, and imply a differential role for IL and PL neurons in regulating affective behaviors. Together, our results support a developmental mechanism for the etiology and pathophysiology of affective disorders and fear-related behaviors. PMID:25209278

Ethanol induced antidepressant-like effect in the mouse forced swimming test: modulation by serotonergic system.

PubMed

Jain, Nishant S; Kannamwar, Uday; Verma, Lokesh

2017-02-01

The present investigation explored the modulatory role of serotonergic transmission in the acute ethanol-induced effects on immobility time in the mouse forced swim test (FST). Acute i.p. administration of ethanol (20% w/v, 2 or 2.5 g/kg, i.p.) decreased the immobility time in FST of mice, indicating its antidepressant-like effect while lower doses of ethanol (1, 1.5 g/kg, i.p.) were devoid of any effect in the FST. The mice pre-treated with a sub-effective dose of 5-HT 2A agonist, DOI (10 μg/mouse, i.c.v.) or 5-HT 1A receptor antagonist, WAY 100635 (0.1 μg/mouse, i.c.v.) but not with the 5-HT 2A/2C antagonist, ketanserin (1.5 μg/mouse, i.c.v.) exhibited a synergistic reduction in the immobility time induced by sub-effective dose of ethanol (1.5 g/kg, i.p.). On the other hand, ethanol (2.5 g/kg, i.p.) failed to decrease the immobility time in mice, pre-treated with 5-HT 1A agonist, 8-OH-DPAT (0.1 μg/mouse, i.c.v.) or ketanserin (1.5 μg/mouse, i.c.v.). In addition, pre-treatment with a 5-HT neuronal synthesis inhibitor, p-CPA (300 mg/kg, i.p. × 3 days) attenuated the anti-immobility effect ethanol (2.5 g/kg, i.p.) in mouse FST. Thus, the results of the present study points towards the essentiality of the central 5-HT transmission at the synapse for the ethanol-induced antidepressant-like effect in the FST wherein the regulatory role of the 5-HT 1A receptor or contributory role of the 5-HT 2A/2C receptor-mediated mechanism is proposed in the anti-immobility effect of acute ethanol in mouse FST.

Role of CB2 receptors in social and aggressive behavior in male mice.

PubMed

Rodríguez-Arias, Marta; Navarrete, Francisco; Blanco-Gandia, M Carmen; Arenas, M Carmen; Aguilar, María A; Bartoll-Andrés, Adrián; Valverde, Olga; Miñarro, José; Manzanares, Jorge

2015-08-01

Male CB1KO mice exhibit stronger aggressive responses than wild-type mice. This study was designed to examine the role of cannabinoid CB2r in social and aggressive behavior. The social interaction test and resident-intruder paradigm were performed in mice lacking CB2r (CB2KO) and in wild-type (WT) littermates. The effects of the CB2r selective agonist JWH133 (1 and 2 mg/kg) on aggression were also evaluated in Oncins France 1 (OF1) mice. Gene expression analyses of monoamine oxidase-A (MAO-A), catechol-o-methyltransferase (COMT), 5-hydroxytryptamine transporter (5-HTT), and 5-HT1B receptor (5HT1Br) in the dorsal raphe nuclei (DR) and the amygdala (AMY) were carried out using real-time PCR. Group-housed CB2KO mice exhibited higher levels of aggression in the social interaction test and displayed more aggression than resident WT mice. Isolation increased aggressive behavior in WT mice but did not affect CB2KO animals; however, the latter mice exhibited higher levels of social interaction with their WT counterparts. MAO-A and 5-HTT gene expression was significantly higher in grouped CB2KO mice. The expression of 5HT1Br, COMT, and MAO-A in the AMY was more pronounced in CB2KO mice than in WT counterparts. Acute administration of the CB2 agonist JWH133 significantly reduced the level of aggression in aggressive isolated OF1 mice, an effect that decreased after pretreatment with the CB2 receptor antagonist AM630. Our results suggest that CB2r is implicated in social interaction and aggressive behavior and deserves further consideration as a potential new target for the management of aggression.

Serotonin transporter protects the placental cells against apoptosis in caspase 3-independent pathway.

PubMed

Hadden, Coedy; Fahmi, Tariq; Cooper, Anthonya; Savenka, Alena V; Lupashin, Vladimir V; Roberts, Drucilla J; Maroteaux, Luc; Hauguel-de Mouzon, Sylvie; Kilic, Fusun

2017-12-01

Serotonin (5-HT) and its specific transporter, SERT play important roles in pregnancy. Using placentas dissected from 18d gestational SERT-knock out (KO), peripheral 5-HT (TPH1)-KO, and wild-type (WT) mice, we explored the role of 5-HT and SERT in placental functions in detail. An abnormal thick band of fibrosis and necrosis under the giant cell layer in SERT-KO placentas appeared only moderately in TPH1-KO and minimally present in WT placentas. The majority of the changes were located at the junctional zone of the placentas in SERT. The etiology of these findings was tested with TUNEL assays. The placentas from SERT-KO and TPH1-KO showed 49- and 8-fold increase in TUNEL-positive cells without a concurrent change in the DNA repair or cell proliferation compared to WT placentas. While the proliferation rate in the embryos of TPH1-KO mice was 16-fold lower than the rate in gestational age matched embryos of WT or SERT-KO mice. These findings highlight an important role of continuous 5-HT signaling on trophoblast cell viability. SERT may contribute to protecting trophoblast cells against cell death via terminating the 5-HT signaling which changes cell death ratio in trophoblast as well as proliferation rate in embryos. However, the cell death in SERT-KO placentas is in caspase 3-independent pathway. © 2017 Wiley Periodicals, Inc.

Effects of Serotonergic Activation by 5-Hydroxytryptophan on Sleep and Body Temperature of C57BL/6J and Interleukin-6-Deficient Mice are Dose and Time Related

PubMed Central

Morrow, Jonathan D.; Vikraman, Sundeep; Imeri, Luca; Opp, Mark R.

2008-01-01

Study Objectives: Extensive data implicate serotonin (5-hydroxytryptamine [5-HT]) in the regulation of sleep. Jouvet has hypothesized that 5-HT promotes wakefulness, yet is necessary for subsequent non-rapid eye movement (NREM) sleep, actions he proposes to be mediated by sleep factors. Studies in rat support this dual role for 5-HT. The objectives of this study were to (1) determine effects of serotonergic activation on sleep of mice and (2) elucidate a potential role for the cytokine interleukin-6 as a sleep factor mediating serotonergic effects on sleep. Design: C57BL/6J and B6.129S6-Il6tm1Kopf (interleukin-6 knockout [IL-6 KO]) mice were purchased from the Jackson Laboratory and instrumented for recording the electroencephalogram and body temperature. After recovery, separate groups of mice were injected intraperitoneally at either light or dark onset with vehicle or with the 5-HT precursor 5-hydroxytryptophan (5-HTP). Sleep-wake behavior was determined and body temperature recorded for 24 hours after injections. Results: 5-HTP induced hypothermia in both mouse strains. When injected at dark onset, the highest dose of 5-HTP (200 mg/kg) increased NREM sleep. Light onset administration initially increased wakefulness, with increases in NREM sleep apparent only during the subsequent dark period. For most parameters, there were no differences in responses between strains. However IL-6 KO mice at some doses exhibited a greater increase in NREM sleep. Conclusions: 5-HTP alters sleep-wake behavior and body temperature of mice in a manner similar to that of rats. Increases in NREM sleep after 5-HTP are apparent only during the dark period, which may represent a fundamental property of the serotonergic system. These results suggest that 5-HT should not be considered either wake promoting or NREM sleep promoting. Rather, the role of 5-HT in the regulation of sleep-wake behavior must be considered within the context of the degree to which the system is activated and the time at which the activation occurs. Citation: Morrow JD; Vikraman S; Imeri L; Opp MR. Effects of serotonergic activation by 5-hydroxytryptophan on sleep and body temperature of C57BL/6J and interleukin-6-deficient mice are dose and time related. SLEEP 2008;31(1):21-33. PMID:18220075

Serotonin Signaling Through the 5-HT1B Receptor and NADPH Oxidase 1 in Pulmonary Arterial Hypertension.

PubMed

Hood, Katie Y; Mair, Kirsty M; Harvey, Adam P; Montezano, Augusto C; Touyz, Rhian M; MacLean, Margaret R

2017-07-01

Serotonin can induce human pulmonary artery smooth muscle cell (hPASMC) proliferation through reactive oxygen species (ROS), influencing the development of pulmonary arterial hypertension (PAH). We hypothesize that in PASMCs, serotonin induces oxidative stress through NADPH-oxidase-derived ROS generation and reduced Nrf-2 (nuclear factor [erythroid-derived 2]-like 2) antioxidant systems, promoting vascular injury. HPASMCs from controls and PAH patients, and PASMCs from Nox1 -/- mice, were stimulated with serotonin in the absence/presence of inhibitors of Src kinase, the 5-HT 1B receptor, and NADPH oxidase 1 (Nox1). Markers of fibrosis were also determined. The pathophysiological significance of our findings was examined in vivo in serotonin transporter overexpressing female mice, a model of pulmonary hypertension. We confirmed thatserotonin increased superoxide and hydrogen peroxide production in these cells. For the first time, we show that serotonin increased oxidized protein tyrosine phosphatases and hyperoxidized peroxiredoxin and decreased Nrf-2 and catalase activity in hPASMCs. ROS generation was exaggerated and dependent on cellular Src-related kinase, 5-HT 1B receptor, and the serotonin transporter in human pulmonary artery smooth muscle cells from PAH subjects. Proliferation and extracellular matrix remodeling were exaggerated in human pulmonary artery smooth muscle cells from PAH subjects and dependent on 5-HT 1B receptor signaling and Nox1, confirmed in PASMCs from Nox1 -/- mice. In serotonin transporter overexpressing mice, SB216641, a 5-HT 1B receptor antagonist, prevented development of pulmonary hypertension in a ROS-dependent manner. Serotonin can induce cellular Src-related kinase-regulated Nox1-induced ROS and Nrf-2 dysregulation, contributing to increased post-translational oxidative modification of proteins and activation of redox-sensitive signaling pathways in hPASMCs, associated with mitogenic responses. 5-HT 1B receptors contribute to experimental pulmonary hypertension by inducing lung ROS production. Our results suggest that 5-HT 1B receptor-dependent cellular Src-related kinase-Nox1-pathways contribute to vascular remodeling in PAH. © 2017 The Authors.

Serotonin Signaling Through the 5-HT1B Receptor and NADPH Oxidase 1 in Pulmonary Arterial Hypertension

PubMed Central

Hood, Katie Y.; Mair, Kirsty M.; Harvey, Adam P.; Montezano, Augusto C.; Touyz, Rhian M.

2017-01-01

Objective— Serotonin can induce human pulmonary artery smooth muscle cell (hPASMC) proliferation through reactive oxygen species (ROS), influencing the development of pulmonary arterial hypertension (PAH). We hypothesize that in PASMCs, serotonin induces oxidative stress through NADPH-oxidase–derived ROS generation and reduced Nrf-2 (nuclear factor [erythroid-derived 2]-like 2) antioxidant systems, promoting vascular injury. Approach and Results— HPASMCs from controls and PAH patients, and PASMCs from Nox1−/− mice, were stimulated with serotonin in the absence/presence of inhibitors of Src kinase, the 5-HT1B receptor, and NADPH oxidase 1 (Nox1). Markers of fibrosis were also determined. The pathophysiological significance of our findings was examined in vivo in serotonin transporter overexpressing female mice, a model of pulmonary hypertension. We confirmed thatserotonin increased superoxide and hydrogen peroxide production in these cells. For the first time, we show that serotonin increased oxidized protein tyrosine phosphatases and hyperoxidized peroxiredoxin and decreased Nrf-2 and catalase activity in hPASMCs. ROS generation was exaggerated and dependent on cellular Src-related kinase, 5-HT1B receptor, and the serotonin transporter in human pulmonary artery smooth muscle cells from PAH subjects. Proliferation and extracellular matrix remodeling were exaggerated in human pulmonary artery smooth muscle cells from PAH subjects and dependent on 5-HT1B receptor signaling and Nox1, confirmed in PASMCs from Nox1−/− mice. In serotonin transporter overexpressing mice, SB216641, a 5-HT1B receptor antagonist, prevented development of pulmonary hypertension in a ROS-dependent manner. Conclusions— Serotonin can induce cellular Src-related kinase–regulated Nox1-induced ROS and Nrf-2 dysregulation, contributing to increased post-translational oxidative modification of proteins and activation of redox-sensitive signaling pathways in hPASMCs, associated with mitogenic responses. 5-HT1B receptors contribute to experimental pulmonary hypertension by inducing lung ROS production. Our results suggest that 5-HT1B receptor–dependent cellular Src-related kinase-Nox1-pathways contribute to vascular remodeling in PAH. PMID:28473438

Antidepressant- and Anxiolytic-Like Effects of New Dual 5-HT1A and 5-HT7 Antagonists in Animal Models

PubMed Central

Pytka, Karolina; Partyka, Anna; Jastrzębska-Więsek, Magdalena; Siwek, Agata; Głuch-Lutwin, Monika; Mordyl, Barbara; Kazek, Grzegorz; Rapacz, Anna; Olczyk, Adrian; Gałuszka, Adam; Błachuta, Marian; Waszkielewicz, Anna; Marona, Henryk; Sapa, Jacek; Filipek, Barbara; Wesołowska, Anna

2015-01-01

The aim of this study was to further characterize pharmacological properties of two phenylpiperazine derivatives: 1-{2-[2-(2,6-dimethlphenoxy)ethoxy]ethyl}-4-(2-methoxyphenyl)piperazynine hydrochloride (HBK-14) and 2-[2-(2-chloro-6-methylphenoxy)ethoxy]ethyl-4-(2- methoxyphenyl)piperazynine dihydrochloride (HBK-15) in radioligand binding and functional in vitro assays as well as in vivo models. Antidepressant-like properties were investigated in the forced swim test (FST) in mice and rats. Anxiolytic-like activity was evaluated in the four-plate test in mice and elevated plus maze test (EPM) in rats. Imipramine and escitalopram were used as reference drugs in the FST, and diazepam was used as a standard anxiolytic drug in animal models of anxiety. Our results indicate that HBK-14 and HBK-15 possess high or moderate affinity for serotonergic 5-HT2, adrenergic α1, and dopaminergic D2 receptors as well as being full 5-HT1A and 5-HT7 receptor antagonists. We also present their potent antidepressant-like activity (HBK-14—FST mice: 2.5 and 5 mg/kg; FST rats: 5 mg/kg) and (HBK-15—FST mice: 1.25, 2.5 and 5 mg/kg; FST rats: 1.25 and 2.5 mg/kg). We show that HBK-14 (four-plate test: 2.5 and 5 mg/kg; EPM: 2.5 mg/kg) and HBK-15 (four-plate test: 2.5 and 5 mg/kg; EPM: 5 mg/kg) possess anxiolytic-like properties. Among the two, HBK-15 has stronger antidepressant-like properties, and HBK-14 displays greater anxiolytic-like activity. Lastly, we demonstrate the involvement of serotonergic system, particularly 5-HT1A receptor, in the antidepressant- and anxiolytic-like actions of investigated compounds. PMID:26554929

Prebiotic administration normalizes lipopolysaccharide (LPS)-induced anxiety and cortical 5-HT2A receptor and IL1-β levels in male mice.

PubMed

Savignac, Helene M; Couch, Yvonne; Stratford, Michael; Bannerman, David M; Tzortzis, George; Anthony, Daniel C; Burnet, Philip W J

2016-02-01

The manipulation of the enteric microbiota with specific prebiotics and probiotics, has been shown to reduce the host's inflammatory response, alter brain chemistry, and modulate anxiety behaviour in both rodents and humans. However, the neuro-immune and behavioural effects of prebiotics on sickness behaviour have not been explored. Here, adult male CD1 mice were fed with a specific mix of non-digestible galacto-oligosaccharides (Bimuno®, BGOS) for 3 weeks, before receiving a single injection of lipopolysaccharide (LPS), which induces sickness behaviour and anxiety. Locomotor and marble burying activities were assessed 4h after LPS injection, and after 24h, anxiety in the light-dark box was assessed. Cytokine expression, and key components of the serotonergic (5-Hydroxytryptamine, 5-HT) and glutamatergic system were evaluated in the frontal cortex to determine the impact of BGOS administration at a molecular level. BGOS-fed mice were less anxious in the light-dark box compared to controls 24h after the LPS injection. Elevated cortical IL-1β concentrations in control mice 28 h after LPS were not observed in BGOS-fed animals. This significant BGOS×LPS interaction was also observed for 5HT2A receptors, but not for 5HT1A receptors, 5HT, 5HIAA, NMDA receptor subunits, or other cytokines. The intake of BGOS did not influence LPS-mediated reductions in marble burying behaviour, and its effect on locomotor activity was equivocal. Together, our data show that the prebiotic BGOS has an anxiolytic effect, which may be related to the modulation of cortical IL-1β and 5-HT2A receptor expression. Our data suggest a potential role for prebiotics in the treatment of neuropsychiatric disorders where anxiety and neuroinflammation are prominent clinical features. Copyright © 2015. Published by Elsevier Inc.

Effects of GABA microinjection into dorsal raphe nucleus on behavior and activity of lateral habenular neurons in mice.

PubMed

Xiao, Jinyu; Song, Meiying; Li, Fengdan; Liu, Xiaofeng; Anwar, Alinur; Zhao, Hua

2017-12-01

The dorsal raphe nucleus (DRN) is a key site for 5-hydroxytryptamine (5-HT) synthesis and release. DRN dysfunction has been implicated in several stress-related disorders, including depression and anxiety. The lateral habenular nucleus (LHb) has been shown to inhibit the activity of DRN 5-HT neurons, and thus the LHb-DRN pathway plays an important role in the pathogenesis of depression. Although it is known that the LHb also receives the projection from the 5-HT neuron in the DRN, whether 5-HT neurons in the DRN can influence activity of the LHb in vivo and whether this effect is related to the induced behavioral changes have not been investigated. In the current study, we determined how injecting γ-aminobutyric acid (GABA) into the DRN to inhibit 5-HT neurons affected behavior and the changes in the activity of LHb neurons in mice. We found that GABA injection into the DRN induced depression-like behavior in mice, as indicated by increased immobility time, and decreased climbing time in the forced swimming test and the tail suspension test, decreased time spent in the center and total distance moved in the open field test. Using extracellular single unit recording, we showed that the firing rate of LHb neurons decreased after GABA microinjection into the DRN. Further, c-Fos expression in LHb neurons was inhibited. Together our results indicate that inhibition of DRN 5-HT neurons can cause decreased LHb activity and depression-like behavior in mice, however this depression-like behavior could be independent of the LHb activity. The observed decrease in LHb activity is probably due to the presence of a negative feedback loop between the DRN and the LHb, which may play a role in maintaining emotional homeostasis. Copyright © 2017 Elsevier Inc. All rights reserved.

Central serotonergic neurons activate and recruit thermogenic brown and beige fat and regulate glucose and lipid homeostasis.

PubMed

McGlashon, Jacob M; Gorecki, Michelle C; Kozlowski, Amanda E; Thirnbeck, Caitlin K; Markan, Kathleen R; Leslie, Kirstie L; Kotas, Maya E; Potthoff, Matthew J; Richerson, George B; Gillum, Matthew P

2015-05-05

Thermogenic brown and beige adipocytes convert chemical energy to heat by metabolizing glucose and lipids. Serotonin (5-HT) neurons in the CNS are essential for thermoregulation and accordingly may control metabolic activity of thermogenic fat. To test this, we generated mice in which the human diphtheria toxin receptor (DTR) was selectively expressed in central 5-HT neurons. Treatment with diphtheria toxin (DT) eliminated 5-HT neurons and caused loss of thermoregulation, brown adipose tissue (BAT) steatosis, and a >50% decrease in uncoupling protein 1 (Ucp1) expression in BAT and inguinal white adipose tissue (WAT). In parallel, blood glucose increased 3.5-fold, free fatty acids 13.4-fold, and triglycerides 6.5-fold. Similar BAT and beige fat defects occurred in Lmx1b(f/f)ePet1(Cre) mice in which 5-HT neurons fail to develop in utero. We conclude 5-HT neurons play a major role in regulating glucose and lipid homeostasis, in part through recruitment and metabolic activation of brown and beige adipocytes. Copyright © 2015 Elsevier Inc. All rights reserved.

Biological mechanisms associated with increased perseveration and hyperactivity in a genetic mouse model of neurodevelopmental disorder.

PubMed

Trent, Simon; Dean, Rachel; Veit, Bonnie; Cassano, Tommaso; Bedse, Gaurav; Ojarikre, Obah A; Humby, Trevor; Davies, William

2013-08-01

Chromosomal deletions at Xp22.3 appear to influence vulnerability to the neurodevelopmental disorders attention deficit hyperactivity disorder (ADHD) and autism. 39,X(Y*)O mice, which lack the murine orthologue of the Xp22.3 ADHD candidate gene STS (encoding steroid sulfatase), exhibit behavioural phenotypes relevant to such disorders (e.g. hyperactivity), elevated hippocampal serotonin (5-HT) levels, and reduced serum levels of dehydroepiandrosterone (DHEA). Here we initially show that 39,X(Y*)O mice are also deficient for the recently-characterised murine orthologue of the Xp22.3 autism candidate gene ASMT (encoding acetylserotonin-O-methyltransferase). Subsequently, to specify potential behavioural correlates of elevated hippocampal 5-HT arising due to the genetic lesion, we compared 39,X(Y*)O MF1 mice to 40,XY MF1 mice on behavioural tasks taxing hippocampal and/or 5-HT function (a 'foraging' task, an object-location task, and the 1-choice serial reaction time task of impulsivity). Although Sts/Asmt deficiency did not influence foraging behaviour, reactivity to familiar objects in novel locations, or 'ability to wait', it did result in markedly increased response rates; these rates correlated with hippocampal 5-HT levels and are likely to index behavioural perseveration, a frequent feature of neurodevelopmental disorders. Additionally, we show that whilst there was no systematic relationship between serum DHEA levels and hippocampal 5-HT levels across 39,X(Y*)O and 40,XY mice, there was a significant inverse linear correlation between serum DHEA levels and activity. Our data suggest that deficiency for genes within Xp22.3 could influence core behavioural features of neurodevelopmental disorders via dissociable effects on hippocampal neurochemistry and steroid hormone levels, and that the mediating neurobiological mechanisms may be investigated in the 39,X(Y*)O model. Copyright © 2012 Elsevier Ltd. All rights reserved.

Attenuation of nicotine's discriminative stimulus effects in rats and its locomotor activity effects in mice by serotonergic 5-HT2A/2C receptor agonists.

PubMed

Batman, Angela M; Munzar, Patrik; Beardsley, Patrick M

2005-05-01

Reports have indicated that administration of nicotine inhibits, while withdrawal of chronically administered nicotine augments effects of serotonergic 5HT2A/2C agonists. It was our objective to determine whether 5HT2A/2C agonists can modulate the discriminative stimulus effects of nicotine in rats or its locomotor activity effects in mice. Adult male Sprague-Dawley rats were trained to discriminate 0.3 mg/kg nicotine base from saline in a two-lever, fixed-ratio (FR10), food-reinforced, operant-conditioning task during daily (Monday-Friday) 15-min experimental sessions. After characterizing a dose-response curve for nicotine, we tested the ability of the 5HT(2A/2C) agonists (+/-)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane HCL (DOI; 0.18-1.0 mg/kg) and 1-(4-bromo-2, 5-dimethoxyphenyl)-2-aminopropane (DOB; 0.1-1.0 mg/kg), the 5HT2C agonist 6-chloro-2-(1-piperazinyl)pyrazine hydrochloride (MK 212; 0.1 mg/kg-1.0 mg/kg), and the 5HT1A agonist (+/-)-8-hydroxy-2-(di-n-propylamino)tetralin hydrobromide (8-OH-DPAT; 0.01 mg/kg-1.0 mg/kg) to modulate nicotine's discriminative stimulus effects. After finding that DOI was able to attenuate the percentage nicotine lever responding (%NLR), we tested for it to also reverse nicotine's effects on locomotor activity in mice. The 5HT2A/2C agonists-in particular DOI-dose dependently attenuated %NLR. The effects of DOI were reversed by the 5HT2A/2C antagonist ketanserin. MK 212 and 8-OH-DPAT had irregular effects among rats and only reduced %NLR to below 50% levels at doses markedly suppressing responding. DOI also dose dependently blocked nicotine's acute rate-lowering locomotor activity effects. These results indicate that activation of serotonin 5HT2A/2C receptors can blunt the discriminative stimulus and locomotor activity effects of nicotine and presents the possibility that activation of these receptors might also be able to attenuate other effects of nicotine.

Forebrain-specific expression of monoamine oxidase A reduces neurotransmitter levels, restores the brain structure, and rescues aggressive behavior in monoamine oxidase A-deficient mice.

PubMed

Chen, Kevin; Cases, Olivier; Rebrin, Igor; Wu, Weihua; Gallaher, Timothy K; Seif, Isabelle; Shih, Jean Chen

2007-01-05

Previous studies have established that abrogation of monoamine oxidase (MAO) A expression leads to a neurochemical, morphological, and behavioral specific phenotype with increased levels of serotonin (5-HT), norepinephrine, and dopamine, loss of barrel field structure in mouse somatosensory cortex, and an association with increased aggression in adults. Forebrain-specific MAO A transgenic mice were generated from MAO A knock-out (KO) mice by using the promoter of calcium-dependent kinase IIalpha (CaMKIIalpha). The presence of human MAO A transgene and its expression were verified by PCR of genomic DNA and reverse transcription-PCR of mRNA and Western blot, respectively. Significant MAO A catalytic activity, autoradiographic labeling of 5-HT, and immunocytochemistry of MAO A were found in the frontal cortex, striatum, and hippocampus but not in the cerebellum of the forebrain transgenic mice. Also, compared with MAO A KO mice, lower levels of 5-HT, norepinephrine, and DA and higher levels of MAO A metabolite 5-hydroxyindoleacetic acid were found in the forebrain regions but not in the cerebellum of the transgenic mice. These results suggest that MAO A is specifically expressed in the forebrain regions of transgenic mice. This forebrain-specific differential expression resulted in abrogation of the aggressive phenotype. Furthermore, the disorganization of the somatosensory cortex barrel field structure associated with MAO A KO mice was restored and became morphologically similar to wild type. Thus, the lack of MAO A in the forebrain of MAO A KO mice may underlie their phenotypes.

Escherichia coli Nissle 1917 enhances bioavailability of serotonin in gut tissues through modulation of synthesis and clearance

PubMed Central

Nzakizwanayo, Jonathan; Dedi, Cinzia; Standen, Guy; Macfarlane, Wendy M.; Patel, Bhavik A.; Jones, Brian V.

2015-01-01

Accumulating evidence shows indigenous gut microbes can interact with the human host through modulation of serotonin (5-HT) signaling. Here we investigate the impact of the probiotic Escherichia coli Nissle 1917 (EcN) on 5-HT signalling in gut tissues. Ex-vivo mouse ileal tissue sections were treated with either EcN or the human gut commensal MG1655, and effects on levels of 5-HT, precursors, and metabolites, were evaluated using amperometry and high performance liquid chromatography with electrochemical detection (HPLC-EC). Exposure of tissue to EcN cells, but not MG1655 cells, was found to increase levels of extra-cellular 5-HT. These effects were not observed when tissues were treated with cell-free supernatant from bacterial cultures. In contrast, when supernatant recovered from untreated ileal tissue was pre-incubated with EcN, the derivative cell-free supernatant was able to elevate 5-HT overflow when used to treat fresh ileal tissue. Measurement of 5-HT precursors and metabolites indicated EcN also increases intracellular 5-HTP and reduces 5-HIAA. The former pointed to modulation of tryptophan hydroxylase-1 to enhance 5-HT synthesis, while the latter indicates an impact on clearance into enterocytes through SERT. Taken together, these findings show EcN is able to enhance 5-HT bioavailability in ileal tissues through interaction with compounds secreted from host tissues. PMID:26616662

Effect of long-term actual spaceflight on the expression of key genes encoding serotonin and dopamine system

NASA Astrophysics Data System (ADS)

Popova, Nina; Shenkman, Boris; Naumenko, Vladimir; Kulikov, Alexander; Kondaurova, Elena; Tsybko, Anton; Kulikova, Elisabeth; Krasnov, I. B.; Bazhenova, Ekaterina; Sinyakova, Nadezhda

The effect of long-term spaceflight on the central nervous system represents important but yet undeveloped problem. The aim of our work was to study the effect of 30-days spaceflight of mice on Russian biosatellite BION-M1 on the expression in the brain regions of key genes of a) serotonin (5-HT) system (main enzymes in 5-HT metabolism - tryptophan hydroxylase-2 (TPH-2), monoamine oxydase A (MAO A), 5-HT1A, 5-HT2A and 5-HT3 receptors); b) pivotal enzymes in DA metabolism (tyrosine hydroxylase, COMT, MAO A, MAO B) and D1, D2 receptors. Decreased expression of genes encoding the 5-HT catabolism (MAO A) and 5-HT2A receptor in some brain regions was shown. There were no differences between “spaceflight” and control mice in the expression of TPH-2 and 5-HT1A, 5-HT3 receptor genes. Significant changes were found in genetic control of DA system. Long-term spaceflight decreased the expression of genes encoding the enzyme in DA synthesis (tyrosine hydroxylase in s.nigra), DA metabolism (MAO B in the midbrain and COMT in the striatum), and D1 receptor in hypothalamus. These data suggested that 1) microgravity affected genetic control of 5-HT and especially the nigrostriatal DA system implicated in the central regulation of muscular tonus and movement, 2) the decrease in the expression of genes encoding key enzyme in DA synthesis, DA degradation and D1 receptor contributes to the movement impairment and dyskinesia produced by the spaceflight. The study was supported by Russian Foundation for Basic Research grant No. 14-04-00173.

Prophylaxis and therapy of mouse mammary carcinomas with doxorubicin and vincristine encapsulated in sterically stabilised liposomes.

PubMed

Vaage, J; Donovan, D; Loftus, T; Uster, P; Working, P

1995-01-01

This study tested the prophylactic efficacies of doxorubicin hydrochloride and vincristine sulphate, encapsulated in sterically stabilised long circulating liposomes, against the spontaneous development of mammary carcinomas in C3H/He mice. Monthly prophylactic intravenous (i.v.) injections of 6 mg/kg doses of liposome-encapsulated doxorubicin (DOX-SL) or 1 mg/kg doses of liposome-encapsulated vincristine (VIN-SL) were begun when retired breeding mice were 26 weeks old. Mice that developed a mammary carcinoma while on the monthly prophylactic protocols were then given weekly i.v. injections of 6 mg/kg DOX-SL or 1 mg/kg VIN-SL to test the therapeutic efficacies of the drugs, and to determine whether the tumours were susceptible or resistant to therapy. The monthly prophylactic injections reduced the incidence of first mammary carcinomas from 87/88 (99%) in untreated mice to 24/42 (57%) in DOX-SL-treated mice and to 26/32 (81%) in VIN-SL-treated mice. Of the mice that developed a mammary tumour while on the prophylactic protocols, 12 of 30 mice were cured by the weekly therapeutic use of DOX-SL, and the growth of 18 tumours was inhibited. The weekly therapeutic use of VIN-SL cured 3 of 8 mice, and inhibited the growth of five tumours. Weekly DOX-SL therapy cured 7 of 22 previously untreated mice. The mean survival of tumour-bearing mice was extended from 24 days in untreated mice to 87 days in DOX-SL-treated mice, which had not received prophylactic treatment. Metastases were found in 29 of 54 untreated mice, and in 3 of 72 mice treated with DOX-SL and VIN-SL. Toxic side effects were limited to a transient weight loss during the weekly treatments. Drug resistance as a result of treatments was not observed.

NATURAL AND ENGINEERED CODING VARIATION IN ANTIDEPRESSANT-SENSITIVE SEROTONIN TRANSPORTERS

PubMed Central

YE, R.; BLAKELY, R. D.

2013-01-01

The presynaptic serotonin (5-HT) transporter (SERT) is a key regulator of 5-HT signaling and is a major target for antidepressant medications and psychostimulants. In recent years, studies of natural and engineered genetic variation in SERT have provided new opportunities to understand structural dimensions of drug interactions and regulation of the transporter, to explore 5-HT contributions to antidepressant action, and to assess the impact of SERT-mediated 5-HT contributions to neuropsychiatric disorders. Here we review three examples from our recent studies where genetic changes in SERT, identified or engineered, have led to new models, findings, and theories that cast light on new dimensions of 5-HT action in the CNS and periphery. First, we review our work to identify specific residues through which SERT recognizes antagonists, and the conversion of this knowledge to the creation of mice lacking high-affinity antidepressant and cocaine sensitivity. Second, we discuss our studies of functional coding variation in SERT that exists in commonly used strains of inbred mice, and how this variation is beginning to reveal novel 5-HT-associated phenotypes. Third, we review our identification and functional characterization of multiple, hyperactive SERT coding variants in subjects with autism. Each of these activities has driven the development of new model systems that can be further exploited to understand the contribution of 5-HT signaling to risk for neuropsychiatric disorders and their treatment. PMID:21893166

Effects of prenatal stress and neonatal handling on anxiety, spatial learning and serotonergic system of male offspring mice.

PubMed

Akatsu, Shigemi; Ishikawa, Chihiro; Takemura, Kaori; Ohtani, Akiko; Shiga, Takashi

2015-12-01

Environmental factors during perinatal period have various effects on behavior. The present study examined the effects of prenatal stress and neonatal handling on anxiety and spatial learning of offspring. Prenatal stress increased anxiety-related behavior of adult offspring, whereas neonatal handling had no effect. In contrast, spatial learning was not affected by prenatal stress, but improved by neonatal handling in both prenatally stressed and non-stressed mice. Next, to elucidate possible brain mechanisms mediating effects of environmental factors on behavior, we focused on serotonin (5-HT) system in the frontal cortex and hippocampus which is involved in anxiety and learning. We examined effects of environmental factors on the mRNA expression of 5-HT1A, 5-HT2A and 5-HT2C receptors in the frontal cortex and hippocampus during postnatal period and adulthood. Both prenatal stress and neonatal handling altered the mRNA expression of 5-HT receptors. These effects were dependent on environmental factors, brain regions and developmental stages. In summary, the present study revealed that prenatal stress and neonatal handling had differential effects on anxiety and spatial learning of offspring, and concomitantly the expression of 5-HT receptors. It was also shown that the effects of prenatal stress on 5-HT system were recovered partially by neonatal handling. Copyright © 2015 Elsevier Ireland Ltd and the Japan Neuroscience Society. All rights reserved.

Pivotal role of oxidative stress in tumor metastasis under diabetic conditions in mice.

PubMed

Ikemura, Mai; Nishikawa, Makiya; Kusamori, Kosuke; Fukuoka, Miho; Yamashita, Fumiyoshi; Hashida, Mitsuru

2013-09-10

Diabetic patients are reported to have a high incidence and mortality of cancer, but little is known about the linkage. In this study, we investigated whether high oxidative stress is involved in the acceleration of tumor metastasis in diabetic mice. Murine melanoma B16-BL6 cells stably labeled with firefly luciferase (B16-BL6/Luc) were inoculated into the tail vein of streptozotocin (STZ)-treated or untreated mice. A luciferase assay demonstrated that tumor cells were present largely in the lung of untreated mice, whereas large numbers of tumor cells were detected in both the lung and liver of STZ-treated mice. Repeated injections of polyethylene glycol-conjugated catalase (PEG-catalase), a long-circulating derivative, reduced the elevated fasting blood glucose levels and plasma lipoperoxide levels of STZ-treated mice, but had no significant effects on these parameters in untreated mice. In addition, the injections significantly reduced the number of tumor cells in the lung and liver in both untreated and STZ-treated mice. Culture of B16-BL6/Luc cells in medium containing over 45 mg/dl glucose hardly affected the proliferation of the cells, whereas the addition of plasma of STZ-treated mice to the medium significantly increased the number of cells. Plasma samples of STZ-treated mice receiving PEG-catalase exhibited no such effect on proliferation. These findings indicate that a hyperglycemia-induced increase in oxidative stress is involved in the acceleration of tumor metastasis, and the removal of systemic hydrogen peroxide by PEG-catalase can inhibit the progression of diabetic conditions and tumor metastasis in diabetes. Copyright © 2013 Elsevier B.V. All rights reserved.

Verification of the causal relationship between subchronic exposures to dinotefuran and depression-related phenotype in juvenile mice.

PubMed

Takada, Tadashi; Yoneda, Naoki; Hirano, Tetsushi; Yanai, Shogo; Yamamoto, Anzu; Mantani, Youhei; Yokoyama, Toshifumi; Kitagawa, Hiroshi; Tabuchi, Yoshiaki; Hoshi, Nobuhiko

2018-04-27

It has been suggested that an increase in the use of pesticides affects neurodevelopment, but there has been no animal experiment showing a causal relation between neonicotinoid pesticides (NNs) and depression. We examined whether dinotefuran (DIN), the most widely used NN in Japan, induces depression. Male mice were administered DIN between 3 and 8 weeks of age, referring to the no-observed-effect level (NOEL). The mice were then subjected to a tail suspension test (TST) and a forced swimming test (FST). After these tests, their brains were dissected for immunohistochemical analyses of serotonin (5-HT). Antidepressant activity in TST and no decrease in 5-HT-positive cells were observed. The subchronic exposure to DIN alone in juvenile male mice may not cause depression-like indication.

Omega-3 fatty acid deficiency does not alter the effects of chronic fluoxetine treatment on central serotonin turnover or behavior in the forced swim test in female rats.

PubMed

McNamara, Robert K; Able, Jessica A; Liu, Yanhong; Jandacek, Ronald; Rider, Therese; Tso, Patrick; Lipton, Jack W

2013-12-01

While translational evidence suggests that long-chain omega-3 fatty acid status is positively associated with the efficacy of selective serotonin reuptake inhibitor drugs, the neurochemical mechanisms mediating this interaction are not known. Here, we investigated the effects of dietary omega-3 (n-3) fatty acid insufficiency on the neurochemical and behavioral effects of chronic fluoxetine (FLX) treatment. Female rats were fed diets with (CON, n=56) or without (DEF, n=40) the n-3 fatty acids during peri-adolescent development (P21-P90), and one half of each group was administered FLX (10mg/kg/day) for 30days (P60-P90) prior to testing. In adulthood (P90), regional brain serotonin (5-HT) and 5-hydroxyindoleacetic (5-HIAA) concentrations, presynaptic markers of 5-HT neurotransmission, behavioral responses in the forced swim test (FST), and plasma FLX and norfluoxetine (NFLX) concentrations were investigated. Peri-adolescent n-3 insufficiency led to significant reductions in cortical docosahexaenoic acid (DHA, 22:6n-3) composition in DEF (-25%, p≤0.0001) and DEF+FLX (-28%, p≤0.0001) rats. Untreated DEF rats exhibited significantly lower regional 5-HIAA/5-HT ratios compared with untreated CON rats, but exhibited similar behavioral responses in the FST. In both CON and DEF rats, chronic FLX treatment similarly and significantly decreased 5-HIAA concentrations and the 5-HIAA/5-HT ratio in the hypothalamus, hippocampus, and nucleus accumbens, brainstem tryptophan hydroxylase-2 mRNA expression, and immobility in the FST. While the FLX-induced reduction in 5-HIAA concentrations in the prefrontal cortex was significantly blunted in DEF rats, the reduction in the 5-HIAA/5-HT ratio was similar to CON rats. Although plasma FLX and NFLX levels were not significantly different in DEF and CON rats, the NFLX/FLX ratio was significantly lower in DEF+FLX rats. These preclinical data demonstrate that n-3 fatty acid deficiency does not significantly reduce the effects of chronic FLX treatment on central 5-HT turnover or behavior in the FST in female rats. © 2013 Elsevier Inc. All rights reserved.

Omega-3 Fatty Acid Deficiency Does Not Alter the Effects of Chronic Fluoxetine Treatment on Central Serotonin Turnover or Behavior in the Forced Swim Test in Female Rats

PubMed Central

McNamara, Robert K.; Able, Jessica A.; Liu, Yanhong; Jandacek, Ronald; Rider, Therese; Tso, Patrick; Lipton, Jack W.

2013-01-01

While translational evidence suggests that long-chain omega-3 fatty acid status is positively associated with the efficacy of selective serotonin reuptake inhibitor drugs, the neurochemical mechanisms mediating this interaction are not known. Here we investigated the effects of dietary omega-3 (n-3) fatty acid insufficiency on the neurochemical and behavioral effects of chronic fluoxetine (FLX) treatment. Female rats were fed diets with (CON, n=56) or without (DEF, n=40) the n-3 fatty acids during peri-adolescent development (P21-P90), and one half of each group were administered FLX (10 mg/kg/d) for 30 d (P60-P90) prior to testing. In adulthood (P90), regional brain serotonin (5-HT) and 5-hydroxyindoleacetic (5-HIAA) concentrations, presynaptic markers of 5-HT neurotransmission, behavioral responses in the forced swim test (FST), and plasma FLX and norfluoxetine (NFLX) concentrations were investigated. Peri-adolescent n-3 insufficiency led to significant reductions in cortical docosahexaenoic acid (DHA, 22:6n-3) composition in DEF (−25%, p≤0.0001) and DEF+FLX (−28%, p≤0.0001) rats. Untreated DEF rats exhibited significantly lower regional 5-HIAA/5-HT ratios compared with untreated CON rats, but exhibited similar behavioral responses in the FST. In both CON and DEF rats, chronic FLX treatment similarly and significantly decreased 5-HIAA concentrations and the 5-HIAA/5-HT ratio in the hypothalamus, hippocampus, and nucleus accumbens, brainstem tryptophan hydroxylase-2 mRNA expression, and immobility in the FST. While the FLX-induced reduction in 5-HIAA concentrations in the prefrontal cortex was significantly blunted in DEF rats, the reduction in the 5-HIAA/5-HT ratio was similar to CON rats. Although plasma FLX and NFLX levels were not significantly different in DEF and CON rats, the NFLX/FLX ratio was significantly lower in DEF+FLX rats. These preclinical data demonstrate that n-3 fatty acid deficiency does not significantly reduce the effects of chronic FLX treatment on central 5-HT turnover or behavior in the FST in female rats. PMID:24090922

Rivastigmine improves hippocampal neurogenesis and depression-like behaviors via 5-HT1A receptor stimulation in olfactory bulbectomized mice.

PubMed

Islam, M R; Moriguchi, S; Tagashira, H; Fukunaga, K

2014-07-11

Rivastigmine is a non-competitive inhibitor of both acetylcholinesterase (AChE) and butylcholinesterase (BuChE) used to treat mild to moderate dementia in Alzheimer's disease (AD) patients. Although rivastigmine reportedly ameliorates cognitive dysfunction in these patients, its ability to improve Behavioral and Psychological Symptoms of Dementia (BPSD) remains unclear. To determine whether rivastigmine treatment antagonizes depression-like behaviors, we chronically administered rivastigmine (0.1-1.0mg/kg) to olfactory bulbectomized (OBX) mice once a day for 2weeks, starting 2weeks after bulbectomy. Chronic treatment at 0.3 or 1.0mg/kg dose dependently and significantly improved depression-like behaviors, as assessed by tail suspension (TST), forced swim (FST), locomotion and novelty-suppressed feeding (NSFT) tests. Importantly, co-administration with WAY-100635 (1.0mg/kg), a 5-HT1A receptor antagonist, but not ketanserin (1.0mg/kg,), a 5-HT2A receptor antagonist, completely blocked rivastigmine-induced anti-depressive effects, suggesting that 5-HT1A receptor stimulation mediates this activity. Consistent with this observation, rivastigmine treatment significantly rescued impaired neurogenesis observed in OBX mice in a 5-HT1A receptor-dependent manner. Furthermore, enhanced protein kinase B (Akt) and extracellular signal-regulated kinase (ERK) phosphorylation seen following rivastigmine treatment was closely associated with improved neurogenesis. These effects were blocked by WAY-100635 but not ketanserin treatment. Finally, we confirmed that 5-HT1A but not 5-HT2A receptor stimulation by specific agonists mimicked rivastigmine-induced anti-depression activity and promoted hippocampal neurogenesis. We conclude that, in addition to enhancing the cholinergic system, rivastigmine treatment restores normal function of the hippocampal serotonergic system, an activity that likely ameliorates depressive behaviors in AD patients. Copyright © 2014 IBRO. Published by Elsevier Ltd. All rights reserved.

The expression and functional significance of the serotonin(2C) receptor in murine contact allergy.

PubMed

El-Nour, Husameldin; Lundeberg, Lena; Boman, Anders; Abramowski, Dorothee; Holst, Mikael; Nordlind, Klas

2007-08-01

Serotonin (5-hydroxytryptamine, 5-HT) was proposed to modulate murine contact allergy by binding to 5-HT(1A/2A) receptors (R). We examined the expression of 5-HT(2C)R in the skin of mice with contact allergy, as well as the effects of an agonist and antagonist of this receptor on the elicitation phase of this type of allergy. Immunohistochemistry revealed the presence of 5-HT(2C)R on epidermal dendritic cells, and in the inflamed skin the cells expressing this antigen were increased in number (P < 0.01) and exhibited longer dendrites than in the control tissue. Furthermore, the majority of these cells also stained positively for I-A, a specific marker for Langerhans cells (LCs). Treatment of the skin of sensitized mice in vivo with RO60-0175 (0.5 and 1.0 mg/kg, once daily for 3 days prior to the challenge with antigen), an agonist for 5-HT(2C)R, enhanced the degree of contact eczema (P < 0.05 and P < 0.01 for the two doses respectively), as indicated by ear thickness. This enhancement could be prevented (P < 0.001) by the 5-HT(2C)R antagonist SB 242084 at 3 mg/kg. Addition of 5 x 10(-5) mol/l RO60-0175 to murine XS52 cells, which resembles LCs, potentiated their secretion of interleukin (IL)-1beta (P < 0.05); whereas 10(-10) mol/l attenuated this secretion (P < 0.05). Under the same conditions, the level of IL-1beta mRNA in these cells (as assessed by RT-PCR) was unaltered suggesting that this agonist may exert its effect on IL-1beta secretion at the post-transcriptional or even at the secretory level. In conclusion, our findings indicate that the 5-HT(2C)R is involved in modulating contact allergy in mice.

Pharmacological Modulation of 5-HT2C Receptor Activity Produces Bidirectional Changes in Locomotor Activity, Responding for a Conditioned Reinforcer, and Mesolimbic DA Release in C57BL/6 Mice.

PubMed

Browne, Caleb J; Ji, Xiaodong; Higgins, Guy A; Fletcher, Paul J; Harvey-Lewis, Colin

2017-10-01

Converging lines of behavioral, electrophysiological, and biochemical evidence suggest that 5-HT 2C receptor signaling may bidirectionally influence reward-related behavior through an interaction with the mesolimbic dopamine (DA) system. Here we directly test this hypothesis by examining how modulating 5-HT 2C receptor activity affects DA-dependent behaviors and relate these effects to changes in nucleus accumbens (NAc) DA release. In C57BL/6 mice, locomotor activity and responding for a conditioned reinforcer (CRf), a measure of incentive motivation, were examined following treatment with three 5-HT 2C receptor ligands: the agonist CP809101 (0.25-3 mg/kg), the antagonist SB242084 (0.25-1 mg/kg), or the antagonist/inverse agonist SB206553 (1-5 mg/kg). We further tested whether doses of these compounds that changed locomotor activity and responding for a CRf (1 mg/kg CP809101, 0.5 mg/kg SB242084, or 2.5 mg/kg SB206553) also altered NAc DA release using in vivo microdialysis in anesthetized mice. CP809101 reduced locomotor activity, responding for a CRf, and NAc DA release. In contrast, both SB242084 and SB206553 enhanced locomotor activity, responding for a CRf, and NAc DA release, although higher doses of SB206553 produced opposite behavioral effects. Pretreatment with the non-selective DA receptor antagonist α-flupenthixol prevented SB242084 from enhancing responding for a CRf. Thus blocking tonic 5-HT 2C receptor signaling can release serotonergic inhibition of mesolimbic DA activity and enhance reward-related behavior. The observed bidirectional effects of 5-HT 2C receptor ligands may have important implications when considering the 5-HT 2C receptor as a therapeutic target for psychiatric disorders, particularly those presenting with motivational dysfunctions.

[Effects of Huoxue Bushen Mixture on skin blood vessel neogenesis and vascular endothelial growth factor expression in hair follicle of C57BL/6 mice].

PubMed

Gao, Shang-pu; Huang, Lan; Yang, Xin-wei

2007-03-01

To investigate the possible stimulating mechanism of Huoxue Bushen Mixture (HXBSM), a traditional Chinese compound medicine, on hair growth of mice via measuring the variance of skin blood vessel neogenesis and vascular endothelial growth factor (VEGF) expression in the hair follicle. Hot rosin and paraffin mixture depilation were used to induce C57BL/6 mice hair follicle to enter from telogen into anagen. Ninety C57BL/6 mice were divided into 3 groups randomly: HXBSM group, Yangxue Shengfa Capsule (YXSFC, another traditional Chinese compound medicine) group and untreated group. The mice were fed with corresponding drugs after modeling. The hair growth of the mice was observed every day. Every ten mice out of each group were executed respectively at day 4, 11 and day 17. Skin blood vessel neogenesis was counted through pathological section and VEGF expression in the hair follicle was measured via immunohistochemical method. The number of local blood vessel neogenisis in the HXBSM group observed was larger than that in the untreated group at day 4 (P<0.05); and evidently larger than that in the YXSFC group and the untreated group at day 11 (P<0.05). The expression of VEGF in the hair follicle was distinctively higher than that in the YXSFC group and the untreated group at day 11 and day 17 (P<0.05). HXBSM up-regulates VEGF expression to accelerate blood vessel neogenesis and hair growth.

Involvement of bilitranslocase and beta-glucuronidase in the vascular protection by hydroxytyrosol and its glucuronide metabolites in oxidative stress conditions.

PubMed

Peyrol, Julien; Meyer, Grégory; Obert, Philippe; Dangles, Olivier; Pechère, Laurent; Amiot, Marie-Josèphe; Riva, Catherine

2018-01-01

Olive oil vascular benefits have been attributed to hydroxytyrosol (HT). However, HT biological actions are still debated because it is extensively metabolized into glucuronides (GCs). The aim of this study was to test HT and GC vasculoprotective effects and the underlying mechanisms using aorta rings from 8-week-old male Wistar rats. In the absence of oxidative stress, incubation with 100 μM HT or GC for 5 min did not exert any vasorelaxing effect and did not influence the vascular function. Conversely, in condition of oxidative stress [upon incubation with 500 μM tert-butylhydroperoxide (t-BHP) for 30 min], preincubation with HT or GC improved acetylcholine-induced vasorelaxation compared with untreated samples (no t-BHP). This protective effect was lost for GC, but not for HT, when a washing step (15 min) was introduced between preincubation with HT or GC and t-BHP addition, suggesting that only HT enters the cells. In agreement, bilitranslocase inhibition with 100 μM phenylmethanesulfonyl fluoride for 20 min reduced significantly HT, but not GC, effect on the vascular function upon stress induction. Moreover, GC protective effect (improvement of endothelium-dependent relaxation in response to acetylcholine) in oxidative stress conditions was reduced by preincubation of aorta rings with 300 μM D-saccharolactone to inhibit β-glucuronidase, which can deconjugate polyphenols. Finally, only HT was detected by high-pressure liquid chromatography in aorta rings incubated with GC and t-BHP. These results suggest that, in conditions of oxidative stress, GC can be deconjugated into HT that is transported through the cell membrane by bilitranslocase to protect vascular function. Copyright © 2017 Elsevier Inc. All rights reserved.

Increased alternate splicing of Htr2c in a mouse model for Prader-Willi syndrome leads disruption of 5HT2C receptor mediated appetite.

PubMed

Garfield, Alastair S; Davies, Jennifer R; Burke, Luke K; Furby, Hannah V; Wilkinson, Lawrence S; Heisler, Lora K; Isles, Anthony R

2016-12-08

Alternate splicing of serotonin (5-hydroxytryptamine; 5-HT) 2C receptor (5-HT 2C R) pre-RNA is negatively regulated by the small nucleolar RNA, Snord115, loss of which is observed in nearly all individuals with Prader-Willi Syndrome (PWS), a multigenic disorder characterised by hyperphagia and obesity. Given the role of the 5-HT 2C R in the regulation of ingestive behaviour we investigated the pathophysiological implications of Snord115 deficiency on 5-HT 2C R regulated appetite in a genotypically relevant PWS mouse model (PWS-IC). Specifically, we demonstrate that loss of Snord115 expression is associated with increased levels of hypothalamic truncated 5-HT 2C R pre-mRNA. The 5-HT 2C R promotes appetite suppression via engagement of the central melanocortin system. Pro-opiomelancortin (Pomc) mRNA levels within the arcuate nucleus of the hypothalamus (ARC) were reduced in PWS-IC mice. We then went on to assess the functional consequences of these molecular changes, demonstrating that PWS-IC mice are unresponsive to an anorectic doses of a 5-HT 2C R agonist and that this is associated with attenuated activation of POMC neurons within the ARC. These data provide new insight into the significance of Htr2c pre-mRNA processing to the physiological regulation of appetite and potentially the pathological manifestation of hyperphagia in PWS. Furthermore, these findings have translational relevance for individuals with PWS who may seek to control appetite with another 5-HT 2C R agonist, the new obesity treatment lorcaserin.

Effect of methergoline on body temperature in mice.

PubMed

Cardano, C; Strocchi, P; Gonni, D; Walsh, M; Agnati, L F

1977-03-01

Serotonin (5-HT) involvement in body temperature regulation has been studied in mice by means of a 5-HT-selective blocking agent (methergoline). This drug causes an effect on body temperature which is dependent on environmental temperature. At environmental temperatures of 25 degrees C and 11 degrees C methergoline has a hypothermic effect, while at 36 degrees C environmental temperature, methergoline has a hyperthermic effect. At 25 degrees C environmental temperature, the hypothermic effect induced by 125 mug/kg i.p. of methergoline could be antagonized by low doses of LAE-32 (80 mug/kg s.c.), while there was not such an antagonism using higher doses of LAE-32 (100 and 300 mug/kg s.c.). This has been explained using Jalfre's hypothesis of the existence of 5-HT inhibitory and excitatory receptors.

Characterization, solubilization and partial purification of serotonin 5-HT1C receptors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yagaloff, K.A.

1986-01-01

/sup 125/I-Lysergic acid diethylamide (/sup 125/I-LSD) binds with high affinity to a unique serotonergic site on rat choroid plexus. These sites were localized to choroid plexus epithelial cells using a novel high resolution autoradiographic technique. In membrane preparations, the serotonergic site density was 3100 fmol/mg protein, which is 10 fold higher than the density of any other serotonergic site in brain homogenates. The pharmacology of this site, termed the 5-HT1c site, does not match that of 5-Ht1a, 5-HT1b or 5HT2 serotonergic sites. 5-Ht1c sites were solubilized from pig choroid plexus using the zwitterionic detergent, CHAPS. High affinity labelling of themore » solubilized site was obtained using the serotonergic radioligand, N1-methyl-2-(/sup 125/I)lysergic acid diethylamide (/sup 125/I-MIL). Choroid plexus tumors obtained from transgenic mice were examined for the presence of serotonin 5-HT1c receptors. /sup 125/I-LSD binding to choroid plexus tumors displays a pharmacological profile that matches the properties of 5-HT1c receptors in normal choroid plexus. The tumor exhibits the highest site density of serotonin receptors (6600 fmol/mg protein) found in any tissue. /sup 125/I-LSD autoradiography of brain sections from transgenic mice shows high levels of specific labelling over the tumor. The affinities of various indolealkyl, phenlakyl and beta-carboline derivatives for the serotonin 5-HT1c receptor were measured in pig choroid plexus using /sup 125/I-MIL. Serotonin precursors and metabolites were all very weak inhibitors of specific /sup 125/I-MIL binding. Structure-affinity relationships were determined for a number of indolealkylamine analogues. Only serotonin is present in cerebrospinal fluid at concentrations near its 5-HT1c inhibition constant, suggesting that serotonin is the natural 5-HT1c agonist.« less

Novel 5-HT5A receptor antagonists ameliorate scopolamine-induced working memory deficit in mice and reference memory impairment in aged rats.

PubMed

Yamazaki, Mayako; Okabe, Mayuko; Yamamoto, Noriyuki; Yarimizu, Junko; Harada, Katsuya

2015-03-01

Despite the human 5-HT5A receptor being cloned in 1994, the biological function of this receptor has not been extensively characterized due to a lack of specific ligands. We recently reported that the selective 5-HT5A receptor antagonist ASP5736 ameliorated cognitive impairment in several animal models of schizophrenia. Given that areas of the brain with high levels of 5-HT5A receptor expression, such as the hippocampus and cerebral cortex, have important functions in cognition and memory, we evaluated the chemically diverse, potent and brain-penetrating 5-HT5A receptor antagonists ASP5736, AS2030680, and AS2674723 in rodent models of cognitive dysfunction associated with dementia. Each of these compounds exhibited a high affinity for recombinant 5-HT5A receptors that was comparable to that of the non-selective ligand of this receptor, lysergic acid diethylamide (LSD). Although each compound had a low affinity for other receptors, 5-HT5A was the only receptor for which all three compounds had a high affinity. Each of the three compounds ameliorated scopolamine-induced working memory deficit in mice and improved reference memory impairment in aged rats at similar doses. Further, ASP5736 decreased the binding of LSD to 5-HT5A receptors in the olfactory bulb of rats in a dose-dependent manner and occupied 15%-50% of brain 5-HT5A receptors at behaviorally effective doses. These results indicate that the 5-HT5A receptor is involved in learning and memory and that treatment with 5-HT5A receptor antagonists might be broadly effective for cognitive impairment associated with not only schizophrenia but also dementia. Copyright © 2015 The Authors. Production and hosting by Elsevier B.V. All rights reserved.

An assessment of the effects of serotonin 6 (5-HT6) receptor antagonists in rodent models of learning.

PubMed

Lindner, Mark D; Hodges, Donald B; Hogan, John B; Orie, Anitra F; Corsa, Jason A; Barten, Donna M; Polson, Craig; Robertson, Barbara J; Guss, Valerie L; Gillman, Kevin W; Starrett, John E; Gribkoff, Valentin K

2003-11-01

Antagonists of serotonin 6 (5-HT6) receptors have been reported to enhance cognition in animal models of learning, although this finding has not been universal. We have assessed the therapeutic potential of the specific 5-HT6 receptor antagonists 4-amino-N-(2,6-bis-methylamino-pyrimidin-4-yl)-benzenesulfonamide (Ro 04-6790) and 5-chloro-N-(4-methoxy-3-piperazin-1-yl-phenyl)-3-methyl-2-benzothiophenesulfonamide (SB-271046) in rodent models of cognitive function. Although mice express the 5-HT6 receptor and the function of this receptor has been investigated in mice, all reports of activity with 5-HT6 receptor antagonists have used rat models. In the present study, receptor binding revealed that the pharmacological properties of the mouse receptor are different from the rat and human receptor: Ro 04-6790 does not bind to the mouse 5-HT6 receptor, so all in vivo testing included in the present report was conducted in rats. We replicated previous reports that 5-HT6 receptor antagonists produce a stretching syndrome previously shown to be mediated through cholinergic mechanisms, but Ro 04-6790 and SB-271046 failed to attenuate scopolamine-induced deficits in a test of contextual fear conditioning. We also failed to replicate the significant effects reported previously in both an autoshaping task and in a version of the Morris water maze. The results of our experiments are not consistent with previous reports that suggested that 5-HT6 antagonists might have therapeutic potential for cognitive disorders.

Tumor Volume Estimation and Quasi-Continuous Administration for Most Effective Bevacizumab Therapy

PubMed Central

Sápi, Johanna; Kovács, Levente; Drexler, Dániel András; Kocsis, Pál; Gajári, Dávid; Sápi, Zoltán

2015-01-01

Background Bevacizumab is an exogenous inhibitor which inhibits the biological activity of human VEGF. Several studies have investigated the effectiveness of bevacizumab therapy according to different cancer types but these days there is an intense debate on its utility. We have investigated different methods to find the best tumor volume estimation since it creates the possibility for precise and effective drug administration with a much lower dose than in the protocol. Materials and Methods We have examined C38 mouse colon adenocarcinoma and HT-29 human colorectal adenocarcinoma. In both cases, three groups were compared in the experiments. The first group did not receive therapy, the second group received one 200 μg bevacizumab dose for a treatment period (protocol-based therapy), and the third group received 1.1 μg bevacizumab every day (quasi-continuous therapy). Tumor volume measurement was performed by digital caliper and small animal MRI. The mathematical relationship between MRI-measured tumor volume and mass was investigated to estimate accurate tumor volume using caliper-measured data. A two-dimensional mathematical model was applied for tumor volume evaluation, and tumor- and therapy-specific constants were calculated for the three different groups. The effectiveness of bevacizumab administration was examined by statistical analysis. Results In the case of C38 adenocarcinoma, protocol-based treatment did not result in significantly smaller tumor volume compared to the no treatment group; however, there was a significant difference between untreated mice and mice who received quasi-continuous therapy (p = 0.002). In the case of HT-29 adenocarcinoma, the daily treatment with one-twelfth total dose resulted in significantly smaller tumors than the protocol-based treatment (p = 0.038). When the tumor has a symmetrical, solid closed shape (typically without treatment), volume can be evaluated accurately from caliper-measured data with the applied two-dimensional mathematical model. Conclusion Our results provide a theoretical background for a much more effective bevacizumab treatment using optimized administration. PMID:26540189

Tumor Volume Estimation and Quasi-Continuous Administration for Most Effective Bevacizumab Therapy.

PubMed

Sápi, Johanna; Kovács, Levente; Drexler, Dániel András; Kocsis, Pál; Gajári, Dávid; Sápi, Zoltán

2015-01-01

Bevacizumab is an exogenous inhibitor which inhibits the biological activity of human VEGF. Several studies have investigated the effectiveness of bevacizumab therapy according to different cancer types but these days there is an intense debate on its utility. We have investigated different methods to find the best tumor volume estimation since it creates the possibility for precise and effective drug administration with a much lower dose than in the protocol. We have examined C38 mouse colon adenocarcinoma and HT-29 human colorectal adenocarcinoma. In both cases, three groups were compared in the experiments. The first group did not receive therapy, the second group received one 200 μg bevacizumab dose for a treatment period (protocol-based therapy), and the third group received 1.1 μg bevacizumab every day (quasi-continuous therapy). Tumor volume measurement was performed by digital caliper and small animal MRI. The mathematical relationship between MRI-measured tumor volume and mass was investigated to estimate accurate tumor volume using caliper-measured data. A two-dimensional mathematical model was applied for tumor volume evaluation, and tumor- and therapy-specific constants were calculated for the three different groups. The effectiveness of bevacizumab administration was examined by statistical analysis. In the case of C38 adenocarcinoma, protocol-based treatment did not result in significantly smaller tumor volume compared to the no treatment group; however, there was a significant difference between untreated mice and mice who received quasi-continuous therapy (p = 0.002). In the case of HT-29 adenocarcinoma, the daily treatment with one-twelfth total dose resulted in significantly smaller tumors than the protocol-based treatment (p = 0.038). When the tumor has a symmetrical, solid closed shape (typically without treatment), volume can be evaluated accurately from caliper-measured data with the applied two-dimensional mathematical model. Our results provide a theoretical background for a much more effective bevacizumab treatment using optimized administration.

Genetic deletion of the norepinephrine transporter decreases vulnerability to seizures

PubMed Central

Kaminski, Rafal M.; Shippenberg, Toni S.; Witkin, Jeffrey M.; Rocha, Beatriz A.

2005-01-01

Norepinephrine (NE) has been reported to modulate neuronal excitability and act as endogenous anticonvulsant. In the present study we used NE transporter knock-out mice (NET-KO), which are characterized by high levels of extracellular NE, to investigate the role of endogenous NE in seizure susceptibility. Seizure thresholds for cocaine (i.p.), pentylenetetrazol (i.v.) and kainic acid (i.v.) were compared in NET-KO, heterozygous (NET-HT) and wild type (NET-WT) female mice. The dose-response curve for cocaine-induced convulsions was significantly shifted to the right in NET-KO mice, indicating higher seizure thresholds. The threshold doses of pentylenetetrazol that induced clonic and tonic seizures were also significantly higher in NET-KO when compared to NET-WT mice. Similarly, NET-KO mice displayed higher resistance to convulsions engendered by kainic acid. For all drugs tested, the response of NET-HT mice was always intermediate. These data provide further support for a role of endogenous NE in the control of seizure susceptibility. PMID:15911120

Role of the 5HT3 Receptor in Alcohol Drinking and Aggression Using A Transgenic Mouse Model

DTIC Science & Technology

2005-09-01

HT3-OE mice, proliferation, survival and differentiation were quantified in the DG and depression-like behavior was examined using the forced swim ... FORCED SWIM TEST 15 animals from each genotype were tested. Mice were placed in a 30 cm diameter, 46 cm tall cylinder of water (22-25°C, depth...26 cm) and forced to swim for 6 minutes as described previously (43, 44). Six behaviors were scored as described by Scramm et al. (45). 1=floating, 2

Sonographic Features of Cervical Lymph Nodes in Patients With Hashimoto Thyroiditis and the Impacts From the Levothyroxine With Prednisone Therapy.

PubMed

Lyu, Guo-Rong; Zheng, Wei-Kun; Lin, Wan-Ling; Zheng, Li-Ping; Guo, Hai-Xin; Li, Li-Ya

2017-11-06

This study aimed to evaluate the ultrasonographic pattern of cervical lymph nodes (CLNs) and whether levothyroxine with prednisone therapy is effective for lymphadenopathy in patients with Hashimoto thyroiditis (HT). This retrospective study was looking at patients with confirmed diagnosis of HT who underwent comprehensive neck ultrasound examination. We reviewed sonographic findings in 127 patients with HT, 234 euthyroid patients with goiter, and 122 healthy subjects. In addition, 30 untreated HT patients with cervical lymphadenopathy were recruited for the levothyroxine with prednisone therapy. We rescanned the patients 9 months after treatment with levothyroxine and prednisone. Patients with HT had a higher rate of CLN detection on ultrasound than euthyroid patients with goiter and healthy subjects at cervical levels III, IV, and VI (P < 0.01). In addition, patients with HT had a higher rate of detection of CLNs with abnormal sonographic features than the other 2 groups, most notably at cervical levels III, IV, and VI (P < 0.01). After the treatment, the mean thyroid volume, thyroid nodule volume, CLN volume, symptom score, and cosmetic grade of 30 HT patients were remarkably decreased (P < 0.01 or P < 0.001). Hashimoto thyroiditis seems to be associated with an increased rate of detection of CLNs with abnormal sonographic features, particularly at cervical levels III, IV, and VI. Therapy with levothyroxine with prednisone is effective for cervical lymphadenopathy in patients with HT.

Ketamine treatment involves medial prefrontal cortex serotonin to induce a rapid antidepressant-like activity in BALB/cJ mice.

PubMed

Pham, T H; Mendez-David, I; Defaix, C; Guiard, B P; Tritschler, L; David, D J; Gardier, A M

2017-01-01

Unlike classic serotonergic antidepressant drugs, ketamine, an NMDA receptor antagonist, exhibits a rapid and persistent antidepressant (AD) activity, at sub-anaesthetic doses in treatment-resistant depressed patients and in preclinical studies in rodents. The mechanisms mediating this activity are unclear. Here, we assessed the role of the brain serotonergic system in the AD-like activity of an acute sub-anaesthetic ketamine dose. We compared ketamine and fluoxetine responses in several behavioral tests currently used to predict anxiolytic/antidepressant-like potential in rodents. We also measured their effects on extracellular serotonin levels [5-HT] ext in the medial prefrontal cortex (mPFCx) and brainstem dorsal raphe nucleus (DRN), a serotonergic nucleus involved in emotional behavior, and on 5-HT cell firing in the DRN in highly anxious BALB/cJ mice. Ketamine (10 mg/kg i.p.) had no anxiolytic-like effect, but displayed a long lasting AD-like activity, i.e., 24 h post-administration, compared to fluoxetine (18 mg/kg i.p.). Ketamine (144%) and fluoxetine (171%) increased mPFCx [5-HT] ext compared to vehicle. Ketamine-induced AD-like effect was abolished by a tryptophan hydroxylase inhibitor, para-chlorophenylalanine (PCPA) pointing out the role of the 5-HT system in its behavioral activity. Interestingly, increase in cortical [5-HT] ext following intra-mPFCx ketamine bilateral injection (0.25 μg/side) was correlated with its AD-like activity as measured on swimming duration in the FST in the same mice. Furthermore, pre-treatment with a selective AMPA receptor antagonist (intra-DRN NBQX) blunted the effects of intra-mPFCx ketamine on both the swimming duration in the FST and mPFCx [5-HT] ext suggesting that the AD-like activity of ketamine required activation of DRN AMPA receptors and recruited the prefrontal cortex/brainstem DRN neural circuit in BALB/c mice. These results confirm a key role of cortical 5-HT release in ketamine's AD-like activity following the blockade of glutamatergic NMDA receptors. Tight interactions between mPFCx glutamatergic and serotonergic systems may explain the differences in this activity between ketamine and fluoxetine in vivo. This article is part of the Special Issue entitled 'Ionotropic glutamate receptors'. Copyright © 2016. Published by Elsevier Ltd.

Natural and engineered coding variation in antidepressant-sensitive serotonin transporters.

PubMed

Ye, R; Blakely, R D

2011-12-01

The presynaptic serotonin (5-HT) transporter (SERT) is a key regulator of 5-HT signaling and is a major target for antidepressant medications and psychostimulants. In recent years, studies of natural and engineered genetic variation in SERT have provided new opportunities to understand structural dimensions of drug interactions and regulation of the transporter, to explore 5-HT contributions to antidepressant action, and to assess the impact of SERT-mediated 5-HT contributions to neuropsychiatric disorders. Here we review three examples from our recent studies where genetic changes in SERT, identified or engineered, have led to new models, findings, and theories that cast light on new dimensions of 5-HT action in the CNS and periphery. First, we review our work to identify specific residues through which SERT recognizes antagonists, and the conversion of this knowledge to the creation of mice lacking high-affinity antidepressant and cocaine sensitivity. Second, we discuss our studies of functional coding variation in SERT that exists in commonly used strains of inbred mice, and how this variation is beginning to reveal novel 5-HT-associated phenotypes. Third, we review our identification and functional characterization of multiple, hyperactive SERT coding variants in subjects with autism. Each of these activities has driven the development of new model systems that can be further exploited to understand the contribution of 5-HT signaling to risk for neuropsychiatric disorders and their treatment. Copyright © 2011. Published by Elsevier Ltd.

Design, synthesis and structure-activity relationship of novel quinoxalin-2-carboxamides as 5-HT3 receptor antagonists for the management of depression.

PubMed

Mahesh, Radhakrishnan; Devadoss, Thangaraj; Pandey, Dilip Kumar; Bhatt, Shvetank; Yadav, Shushil Kumar

2010-11-15

A novel series of quinoxalin-2-carboxamides were designed based on the ligand-based approach, employing a three-point pharmacophore model; it consists of an aromatic residue and a linking carbonyl group and a basic nitrogen. The target new chemical entities were synthesized from the key intermediate, quinoxalin-2-carboxylic acid, by coupling it with various amines in the presence of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC·HCl) and 1-hydroxybenzotriazole (HOBt). The obtained compounds' structures were confirmed by spectral data. The target new chemical entities were evaluated for their 5-HT(3) receptor antagonisms in longitudinal muscle myenteric plexus preparation from guinea pig ileum against 5-HT(3) agonist, 2-methyl-5-HT, which was expressed in the form of pA(2) value. All the synthesized compounds showed antagonism towards 5-HT(3) receptor; based on this result, a structure-activity relationship was derived, which reveals that the aromatic residue in 5-HT(3) receptor antagonists may have hydrophobic interaction with 5-HT(3) receptor. Regardless of their antagonistic potentials, all the synthesized molecules were screened for their anti-depressant potentials by using forced swim test in mice model; interestingly none of the tested compounds affect the locomotion of mice in the tested dose levels. Compounds with significant pA(2) values exhibited good anti-depressant-like activity as compared to the vehicle-treated group. Copyright © 2010 Elsevier Ltd. All rights reserved.

Effective remediation of fish processing waste using mixed culture biofilms capable of simultaneous nitrification and denitrification.

PubMed

Markande, Anoop R; Kapagunta, Chandrika; Patil, Pooja S; Nayak, Binaya B

2016-09-01

Fish processing waste water causes pollution and eutrophication of water bodies when released untreated. Use of bacteria capable of simultaneous nitrification and denitrification (SND) as biofilms on carriers in a moving bed bioreactor (MBBR) is a popular approach but seldom used for fish processing waste water remediation. Here, we studied the variations in biofilm formation and application activities by isolates Lysinibacillus sp. HT13, Alcaligenes sp. HT15 and Proteus sp. HT37 previously reported by us. While HT13 and HT15 formed significantly higher biofilms in polystyrene microtitre plates than on carriers, HT37 exhibited highest on carriers. A consortium of the three selected bacteria grown as biofilm on MBBR carriers exhibited better remediation of ammonia (200-600 ppm and 50 mM) than the individual isolates on carriers. The mixed biofilm set on the carriers was used for nitrogenous waste removal from fish processing waste water in 2 and 20 L setups. The total nitrogen estimated by elemental analysis showed complete remediation from 250 ppm in both 2 and 20 L waste water systems within 48 h. The usual toxic nitrogenous components-ammonia, nitrite and nitrate were also remediated efficiently. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Therapeutic potential of silymarin in chronic unpredictable mild stress induced depressive-like behavior in mice.

PubMed

Thakare, Vishnu N; Patil, Rajesh R; Oswal, Rajesh J; Dhakane, Valmik D; Aswar, Manoj K; Patel, Bhoomika M

2018-02-01

Silymarin, a plant-derived polyphenolic flavonoid of Silybum marianum, elicited significant antidepressant-like activity in an acute restraint stress model of depression. It improved monoamines, mainly 5-hydroxytryptamine (5-HT) levels in the cortex, dopamine (DA) and norepinephrine (NE) in the cerebellum in mice. The present study was undertaken to explore the antidepressant potential of silymarin in chronic unpredictable mild stress (CUMS) induced depressive-like behavior in mice, and to find out its probable mechanism(s) of action, mainly neurogenesis, neuroinflammation, and/or oxidative stress. The mice were subjected to CUMS for 28 days (4 weeks) and administered with silymarin (100 mg/kg and 200 mg/kg), or fluoxetine or vehicle from days 8 to 28 (3 weeks simultaneously). Animals were evaluated for behavioral changes, such as anhedonia by sucrose preference test, behavioral despair by forced swim test, and exploratory behaviors by an open field test. In addition, neurobiochemical alterations, mainly monoamines, 5-HT, NE, DA, neurotrophic factor BDNF, and cytokines, IL-6, TNF-α, oxidant-antioxidant parameters by determining the malondialdehyde formation (an index of lipid peroxidation process), superoxide dismutase (SOD) and catalase (CAT) activity in hippocampus and cerebral cortex along with serum corticosterone were investigated. Our findings reveal that mice subjected to CUMS exhibited lower sucrose preference, increase immobility time without affecting general locomotion of the animals, and reduce BDNF, 5-HT, NE, and DA level, increased serum corticosterone, IL-6 and TNF-α along with an oxidant-antioxidant imbalance in the hippocampus and cerebral cortex. Silymarin significantly reversed the CUMS-induced changes in the hippocampus and cerebral cortex in mice. Thus, the possible mechanism involved in the antidepressant-like activity of silymarin is correlated to the alleviation of monoaminergic, neurogenesis (enhancing 5-HT, NE, and BDNF levels), and attenuation of inflammatory cytokines system and oxidative stress by modulation of corticosterone response, restoration of antioxidant defense system in cerebral cortex and hippocampus.

Activation of serotonin 2C receptors in dopamine neurons inhibits binge-like eating in mice

USDA-ARS?s Scientific Manuscript database

Neural networks that regulate binge eating remain to be identified, and effective treatments for binge eating are limited. We combined neuroanatomic, pharmacologic, electrophysiological, Cre-lox, and chemogenetic approaches to investigate the functions of 5-hydroxytryptamine (5-HT) 2C receptor (5-HT...

Further studies on the mode of action of psychotomimetic drugs

PubMed Central

Bradley, P.B.; Briggs, I.

1974-01-01

1 The actions of 5-methoxytryptamine (5-MeOT), N,N-dimethyltryptamine (DMT), 5-hydroxy-N,N-dimethyltryptamine (bufotenine, 5-HODMT) and 5-methoxy-N,N-dimethyltryptamine (5-MeODMT), and their interactions with 5-hydroxytryptamine (5-HT), acetylcholine, (-)-noradrenaline, and glutamate were studied by microiontophoresis on single neurones in the brain stem of rats anaesthetized with urethane or decerebrate cats. 2 Like D-lysergic acid diethylamide (LSD 25) the three psychotomimetic derivatives (DMT, 5-HODMT, 5-MeODMT) specifically antagonized 5-HT excitations of single neurones, but the non-psychotomimetic 5-MeOT had no antagonistic effects. 3 In contrast to LSD 25, the psychotomimetic tryptamines only rarely antagonized glutamate effects, indicating that the excitatory 5-HT receptors and the glutamate receptors on the same neurones may be closely related spatially, but are separate. 4 The methylated tryptamine derivatives were able to mimic the actions of 5-HT on neurones. The non-psychotomimetic 5-MeOT was most potent in this respect, while the other three derivatives which are psychotomimetic, were less active. 5 The 5-HT mimicking actions of 5-MeOT were the same in rats pretreated with p-chlorophenylalanine or reserpine as in untreated rats. It therefore seems that the 5-HT mimicking actions are unlikely to be due to release of 5-HT, but are due to direct actions on 5-HT receptors. 6 The evidence presented supports the hypothesis that LSD-like psychotomimetics act by an antagonism of 5-HT in the lower brain stem, and is not compatible with the suggestion that the psychotomimetic action of these drugs is related to 5-HT receptor stimulation. PMID:4277490

Quinolone therapy of Klebsiella pneumoniae sepsis following irradiation: Comparison of pefloxacin, ciprofloxacin, and ofloxacin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brook, I.; Elliott, T.B.; Ledney, G.D.

Exposure to whole-body irradiation is associated with fatal gram-negative sepsis. The effect of oral therapy with three quinolones, pefloxacin, ciprofloxacin, and ofloxacin, for orally acquired Klebsiella pneumoniae infection was tested in B6D2F1 mice exposed to 8.0 Gy whole-body irradiation from bilaterally positioned 60Co sources. A dose of 10(8) organisms was given orally 2 days after irradiation, and therapy was started 1 day later. Quinolones reduced colonization of the ileum with K. pneumoniae: 16 of 28 (57%) untreated mice harbored the organisms, compared to only 12 of 90 (13%) mice treated with quinolones (P less than 0.005). K. pneumoniae was isolatedmore » from the livers of 6 of 28 untreated mice, compared to only 1 of 90 treated mice (P less than 0.001). Only 5 of 20 (25%) untreated mice survived for at least 30 days compared with 17 of 20 (85%) mice treated with ofloxacin, 15 of 20 (75%) mice treated with pefloxacin, and 14 of 20 (70%) treated with ciprofloxacin (P less than 0.05). These data illustrate the efficacy of quinolones for oral therapy of orally acquired K. pneumoniae infection in irradiated hosts.« less

Glutamate input in the dorsal raphe nucleus as a determinant of escalated aggression in male mice.

PubMed

Takahashi, Aki; Lee, Ray X; Iwasato, Takuji; Itohara, Shigeyoshi; Arima, Hiroshi; Bettler, Bernhard; Miczek, Klaus A; Koide, Tsuyoshi

2015-04-22

Although the dorsal raphe nucleus (DRN) has long been linked to neural control of aggression, little is known about the regulatory influences of the DRN when an animal engages in either adaptive species-typical aggressive behavior or escalated aggression. Therefore it is important to explore which neurotransmitter inputs into the DRN determine the escalation of aggression in male mice. Previously, we observed that microinjection of the GABAB receptor agonist baclofen into the DRN escalates aggressive behavior in male mice. Here, we used a serotonin (5-HT) neuron-specific GABAB receptor knock-out mouse to demonstrate that baclofen acts on nonserotonergic neurons to escalate aggression. Intra-DRN baclofen administration increased glutamate release, but did not alter GABA release, within the DRN. Microinjection of l-glutamate into the DRN escalated dose-dependently attack bites toward an intruder. In vivo microdialysis showed that glutamate release increased in the DRN during an aggressive encounter, and the level of glutamate was further increased when the animal was engaged in escalated aggressive behavior after social instigation. Finally, 5-HT release was increased within the DRN and also in the medial prefrontal cortex when animals were provoked by social instigation, and during escalated aggression after social instigation, but this increase in 5-HT release was not observed when animals were engaged in species-typical aggression. In summary, glutamate input into the DRN is enhanced during escalated aggression, which causes a phasic increase of 5-HT release from the DRN 5-HT neurons. Copyright © 2015 the authors 0270-6474/15/356452-12$15.00/0.

Acquisition session length modulates consolidation effects produced by 5-HT2C ligands in a mouse autoshaping-operant procedure.

PubMed

Walker, Ellen A; Foley, John J

2010-03-01

Although the neurotransmitter, 5-hydroxytryptamine (serotonin, 5-HT), has been implicated as a mediator of learning and memory, the specific role of 5-HT receptors in rodents requires further delineation. In this study, 5-HT2C receptor ligands of varying relative intrinsic efficacies were tested in a mouse learning and memory model called autoshaping-operant. On day 1, mice were placed in experimental chambers and presented with a tone on a variable interval schedule. The tone remained on for 6 s or until a nose-poke response occurred to produce a dipper with Ensure solution. Mice were then injected with saline, MK212 (full agonist), m-chlorophenylpiperazine (partial agonist), mianserin, and SB206 553 (inverse agonists), and methysergide and (+)-2-bromo lysergic acid diethylamide (+)-hydrogen tartrate (neutral antagonists). Each compound was injected after either 1 or 2-h acquisition sessions on day 1 to investigate the role of acquisition session length on consolidation. Day 1 injection of the 5-HT2C inverse agonist mianserin produced greater retrieval impairments of the autoshaped operant response on day 2 than any other agent tested. Furthermore, decreasing the length of the acquisition session to 1h significantly increased the difficulty of the autoshaping task further modulating the consolidation effects produced by the 5-HT2C ligands tested.

Drinking water treatment is not associated with an observed increase in neural tube defects in mice

PubMed Central

Melin, Vanessa E.; Johnstone, David W.; Etzkorn, Felicia A.

2018-01-01

Disinfection by-products (DBPs) arise when natural organic matter in source water reacts with disinfectants used in the water treatment process. Studies have suggested an association between DBPs and birth defects. Neural tube defects (NTDs) in embryos of untreated control mice were first observed in-house in May 2006 and have continued to date. The source of the NTD-inducing agent was previously determined to be a component of drinking water. Tap water samples from a variety of sources were analyzed for trihalomethanes (THMs) to determine if they were causing the malformations. NTDs were observed in CD-1 mice provided with treated and untreated surface water. Occurrence of NTDs varied by water source and treatment regimens. THMs were detected in tap water derived from surface water but not detected in tap water derived from a groundwater source. THMs were absent in untreated river water and laboratory purified waters, yet the percentage of NTDs in untreated river water were similar to the treated water counterpart. These findings indicate that THMs were not the primary cause of NTDs in the mice since the occurrence of NTDs was unrelated to drinking water disinfection. PMID:24497082

Genetic and Modeling Approaches Reveal Distinct Components of Impulsive Behavior

PubMed Central

Nautiyal, Katherine M; Wall, Melanie M; Wang, Shuai; Magalong, Valerie M; Ahmari, Susanne E; Balsam, Peter D; Blanco, Carlos; Hen, René

2017-01-01

Impulsivity is an endophenotype found in many psychiatric disorders including substance use disorders, pathological gambling, and attention deficit hyperactivity disorder. Two behavioral features often considered in impulsive behavior are behavioral inhibition (impulsive action) and delayed gratification (impulsive choice). However, the extent to which these behavioral constructs represent distinct facets of behavior with discrete biological bases is unclear. To test the hypothesis that impulsive action and impulsive choice represent statistically independent behavioral constructs in mice, we collected behavioral measures of impulsivity in a single cohort of mice using well-validated operant behavioral paradigms. Mice with manipulation of serotonin 1B receptor (5-HT1BR) expression were included as a model of disordered impulsivity. A factor analysis was used to characterize correlations between the measures of impulsivity and to identify covariates. Using two approaches, we dissociated impulsive action from impulsive choice. First, the absence of 5-HT1BRs caused increased impulsive action, but not impulsive choice. Second, based on an exploratory factor analysis, a two-factor model described the data well, with measures of impulsive action and choice separating into two independent factors. A multiple-indicator multiple-causes analysis showed that 5-HT1BR expression and sex were significant covariates of impulsivity. Males displayed increased impulsivity in both dimensions, whereas 5-HT1BR expression was a predictor of increased impulsive action only. These data support the conclusion that impulsive action and impulsive choice are distinct behavioral phenotypes with dissociable biological influences that can be modeled in mice. Our work may help inform better classification, diagnosis, and treatment of psychiatric disorders, which present with disordered impulsivity. PMID:27976680

Distinct circuits underlie the effects of 5-HT1B receptors on aggression and impulsivity

PubMed Central

Nautiyal, Katherine M.; Tanaka, Kenji F.; Barr, Mary M.; Tritschler, Laurent; Le Dantec, Yannick; David, Denis J.; Gardier, Alain M.; Blanco, Carlos; Hen, René; Ahmari, Susanne E.

2015-01-01

Summary Impulsive and aggressive behaviors are both modulated by serotonergic signaling, specifically through the serotonin 1B receptor (5-HT1BR). 5-HT1BR knockout mice show increased aggression and impulsivity, and 5-HT1BR polymorphisms are associated with aggression and drug addiction in humans. To dissect the mechanisms by which the 5-HT1BR affects these phenotypes, we developed a mouse model to spatially and temporally regulate 5-HT1BR expression. Our results demonstrate that forebrain 5-HT1B heteroreceptors expressed during an early postnatal period contribute to the development of the neural systems underlying adult aggression. However, distinct heteroreceptors acting during adulthood are involved in mediating impulsivity. Correlating with the impulsivity, dopamine in the nucleus accumbens is elevated in the absence of 5-HT1BRs, and normalized following adult rescue of the receptor. Overall, these data show that while adolescent expression of 5-HT1BRs influences aggressive behavior, a distinct set of 5-HT1B receptors modulate impulsive behavior during adulthood. PMID:25892302

Nootropic activity of Albizzia lebbeck in mice.

PubMed

Chintawar, S D; Somani, R S; Kasture, Veena S; Kasture, S B

2002-08-01

The effect of saponin containing n-butanolic fraction (BF) extracted from dried leaves of Albizzia lebbeck on learning and memory was studied in albino mice using passive shock avoidance paradigm and the elevated plus maze. Significant improvement was observed in the retention ability of the normal and amnesic mice as compared to their respective controls. We have also studied the effects of BF on the behavior influenced by serotonin (5-HT), noradrenaline and dopamine. The brain levels of serotonin, gamma-aminobutyric acid (GABA) and dopamine were also estimated to correlate the behavior with neurotransmitter levels. The brain concentrations of GABA and dopamine were decreased, whereas the 5-HT level was increased. The data indicate the involvement of monoamine neurotransmitters in the nootropic action of BF of A. lebbeck.

Metabotropic Glutamate2 Receptors Play a Key Role in Modulating Head Twitches Induced by a Serotonergic Hallucinogen in Mice

PubMed Central

Benvenga, Mark J.; Chaney, Stephen F.; Baez, Melvyn; Britton, Thomas C.; Hornback, William J.; Monn, James A.; Marek, Gerard J.

2018-01-01

There is substantial evidence that glutamate can modulate the effects of 5-hydroxytryptamine2A (5-HT2A) receptor activation through stimulation of metabotropic glutamate2/3 (mGlu2/3) receptors in the prefrontal cortex. Here we show that constitutive deletion of the mGlu2 gene profoundly attenuates an effect of 5-HT2A receptor activation using the mouse head twitch response (HTR). MGlu2 and mGlu3 receptor knockout (KO) as well as age-matched ICR (CD-1) wild type (WT) mice were administered (±)1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI) and observed for head twitch activity. DOI failed to produce significant head twitches in mGlu2 receptor KO mice at a dose 10-fold higher than the peak effective dose in WT or mGlu3 receptor KO mice. In addition, the mGlu2/3 receptor agonist LY379268, and the mGlu2 receptor positive allosteric modulator (PAM) CBiPES, potently blocked the HTR to DOI in WT and mGlu3 receptor KO mice. Conversely, the mGlu2/3 receptor antagonist LY341495 (10 mg/kg) increased the HTR produced by DOI (3 mg/kg) in mGlu3 receptor KO mice. Finally, the mGlu2 receptor potentiator CBiPES was able to attenuate the increase in the HTR produced by LY341495 in mGlu3 receptor KO mice. Taken together, all of these results are consistent with the hypothesis that that DOI-induced head twitches are modulated by mGlu2 receptor activation. These results also are in keeping with a critical autoreceptor function for mGlu2 receptors in the prefrontal cortex with differential effects of acute vs. chronic perturbation (e.g., constitutive mGlu2 receptor KO mice). The robust attenuation of DOI-induced head twitches in the mGlu2 receptor KO mice appears to reflect the critical role of glutamate in ongoing regulation of 5-HT2A receptors in the prefrontal cortex. Future experiments with inducible knockouts for the mGlu2 receptor and/or selective mGlu3 receptor agonists/PAMs/antagonists could provide an important tools in understanding glutamatergic modulation of prefrontal cortical 5-HT2A receptor function. PMID:29599719

Caveolin-1: Functional Insights into Its Role in Muscarine- and Serotonin-Induced Smooth Muscle Constriction in Murine Airways

PubMed Central

Keshavarz, Maryam; Schwarz, Heike; Hartmann, Petra; Wiegand, Silke; Skill, Melanie; Althaus, Mike; Kummer, Wolfgang; Krasteva-Christ, Gabriela

2017-01-01

An increased bronchoconstrictor response is a hallmark in the progression of obstructive airway diseases. Acetylcholine and 5-hydroxytryptamine (5-HT, serotonin) are the major bronchoconstrictors. There is evidence that both cholinergic and serotonergic signaling in airway smooth muscle (ASM) involve caveolae. We hypothesized that caveolin-1 (cav-1), a structural protein of caveolae, plays an important regulatory role in ASM contraction. We analyzed airway contraction in different tracheal segments and extra- and intrapulmonary bronchi in cav-1 deficient (cav-1−/−) and wild-type mice using organ bath recordings and videomorphometry of methyl-beta-cyclodextrin (MCD) treated and non-treated precision-cut lung slices (PCLS). The presence of caveolae was investigated by electron microscopy. Receptor subtypes driving 5-HT-responses were studied by RT-PCR and videomorphometry after pharmacological inhibition with ketanserin. Cav-1 was present in tracheal epithelium and ASM. Muscarine induced a dose dependent contraction in all airway segments. A significantly higher Emax was observed in the caudal trachea. Although, caveolae abundancy was largely reduced in cav-1−/− mice, muscarine-induced airway contraction was maintained, albeit at diminished potency in the middle trachea, in the caudal trachea and in the bronchus without changes in the maximum efficacy. MCD-treatment of PLCS from cav-1−/− mice reduced cholinergic constriction by about 50%, indicating that cholesterol-rich plasma domains account for a substantial portion of the muscarine-induced bronchoconstriction. Notably, cav-1-deficiency fully abrogated 5-HT-induced contraction of extrapulmonary airways. In contrast, 5-HT-induced bronchoconstriction was fully maintained in cav-1-deficient intrapulmonary bronchi, but desensitization upon repetitive stimulation was enhanced. RT-PCR analysis revealed 5-HT1B, 5-HT2A, 5-HT6, and 5-HT7 receptors as the most prevalent subtypes in the airways. The 5-HT-induced-constriction in PCLS could be antagonized by ketanserin, a 5-HT2A receptor inhibitor. In conclusion, the role of cav-1, caveolae, and cholesterol-rich plasma domains in regulation of airway tone are highly agonist-specific and dependent on airway level. Cav-1 is indispensable for serotonergic contraction of extrapulmonary airways and modulates cholinergic constriction of the trachea and main bronchus. Thus, cav-1/caveolae shall be considered in settings such as bronchial hyperreactivity in common airway diseases and might provide an opportunity for modulation of the constrictor response. PMID:28555112

Paeonol attenuates lipopolysaccharide-induced depressive-like behavior in mice.

PubMed

Tao, Weiwei; Wang, Hanqing; Su, Qiang; Chen, Yanyan; Xue, Wenda; Xia, Baomei; Duan, Jinao; Chen, Gang

2016-04-30

The present study was designed to detect the anti-depressant effects of paeonol and the possible mechanisms in the lipopolysaccharide-induced depressive-like behavior. Open-field test(OFT), tail suspension test(TST) and forced swimming test(FST) were used to evaluate the behavioral activity. The contents of 5-hydroxytryptamine (5-HT) and norepinephrine (NE) in mice hippocampus were determined by HPLC-ECD. Serum interleukin (IL)-1β, IL-6 and tumor necrosis factor (TNF)-α levels were evaluated by enzyme-linked immunosorbent assay (ELISA). Our results showed that LPS significantly decreased the levels of 5-HT and NE in the hippocampus. LPS also reduced open-field activity, as well as increased immobility duration in FST and TST. Paeonol administration could effectively reverse the alterations in the concentrations of 5-HT, NE and reduce the IL-6 and TNF-α levels. Moreover, paeonol effectively downregulated brain-derived neurotrophic factor (BDNF), tropomyosin-related kinase B (TrkB) and Nuclear factor-κB (NF-κB) in hippocampal. In conclusion, paeonol administration exhibited significant antidepressant-like effects in mice with LPS-induced depression. Copyright © 2016. Published by Elsevier Ireland Ltd.

Specific patterns of spinal metabolites underlying α-Me-5-HT-evoked pruritus compared with histamine and capsaicin assessed by proton nuclear magnetic resonance spectroscopy.

PubMed

Liu, Taotao; He, Zhigang; Tian, Xuebi; Kamal, Ghulam Mustafa; Li, Zhixiao; Liu, Zeyuan; Liu, Huili; Xu, Fuqiang; Wang, Jie; Xiang, Hongbing

2017-06-01

The mechanism behind itching is not well understood. Proton nuclear magnetic resonance ( 1 H-NMR) spectroscopic analysis of spinal cord extracts provides a quick modality for evaluating the specific metabolic activity of α-Me-5-HT-evoked pruritus mice. In the current study, four groups of young adult male C57Bl/6 mice were investigated; one group treated with saline, while the other groups intradermally injected with α-Me-5-HT (histamine independent pruritogen), histamine (histamine dependent pruritogen) and capsaicin (algogenic substance), respectively. The intradermal microinjection of α-Me-5-HT and histamine resulted in a dramatic increase in the itch behavior. Furthermore, the results of NMR studies of the spinal cord extracts revealed that the metabolites show very different patterns for these different drugs, especially when comparing α-Me-5-HT and capsaicin. All the animals in the groups of α-Me-5-HT and capsaicin were completely separated using the metabolite parameters and principal component analysis. For α-Me-5-HT, the concentrations of glutamate, GABA, glycine and aspartate increased significantly, especially for GABA (increased 17.2%, p=0.008). Furthermore, the concentration of NAA increased, but there was no significant difference (increased 11.3%, p=0.191) compared to capsaicin (decreased 29.1%, p=0.002). Thus the application of magnetic resonance spectroscopy technique, coupled with statistical analysis, could further explain the mechanism behind itching evoked by α-Me-5-HT or other drugs. It can thus improve our understanding of itch pathophysiology and pharmacological therapies which may contribute to itch relief. Copyright © 2017 Elsevier B.V. All rights reserved.

Inhibition of serotonin but not norepinephrine transport during development produces delayed, persistent perturbations of emotional behaviors in mice.

PubMed

Ansorge, Mark S; Morelli, Emanuela; Gingrich, Jay A

2008-01-02

Serotonin (5-HT) acts as a neurotransmitter, but also modulates brain maturation during early development. The demonstrated influence of genetic variants on brain function, personality traits, and susceptibility to neuropsychiatric disorders suggests a critical importance of developmental mechanisms. However, little is known about how and when developmentally perturbed 5-HT signaling affects circuitry and resulting behavior. The 5-HT transporter (5-HTT) is a key regulator of extracellular 5-HT levels and we used pharmacologic strategies to manipulate 5-HTT function during development and determine behavioral consequences. Transient exposure to the 5-HTT inhibitors fluoxetine, clomipramine, and citalopram from postnatal day 4 (P4) to P21 produced abnormal emotional behaviors in adult mice. Similar treatment with the norepinephrine transporter (NET) inhibitor, desipramine, did not adversely affect adult behavior, suggesting that 5-HT and norepinephrine (NE) do not share the same effects on brain development. Shifting our period of treatment/testing to P90/P185 failed to mimic the effect of earlier exposure, demonstrating that 5-HT effects on adult behavior are developmentally specific. We have hypothesized that early-life perturbations of 5-HT signaling affect corticolimbic circuits that do not reach maturity until the peri-adolescent period. In support of this idea, we found that abnormal behaviors resulting from postnatal fluoxetine exposure have a post-pubescent onset and persist long after reaching adult age. A better understanding of the underlying 5-HT sensitive circuits and how they are perturbed should lead to new insights into how various genetic polymorphisms confer their risk to carriers. Furthermore, these studies should help determine whether in utero exposure to 5-HTT blocking drugs poses a risk for behavioral abnormalities in later life.

A Functional Tph2 C1473G Polymorphism Causes an Anxiety Phenotype via Compensatory Changes in the Serotonergic System

PubMed Central

Berger, Stefan M; Weber, Tillmann; Perreau-Lenz, Stephanie; Vogt, Miriam A; Gartside, Sarah E; Maser-Gluth, Christiane; Lanfumey, Laurence; Gass, Peter; Spanagel, Rainer; Bartsch, Dusan

2012-01-01

The association of single-nucleotide polymorphisms (SNPs) in the human tryptophan hydroxylase 2 (TPH2) gene with anxiety traits and depression has been inconclusive. Observed inconsistencies might result from the fact that TPH2 polymorphisms have been studied in a genetically heterogeneous human population. A defined genetic background, control over environmental factors, and the ability to analyze the molecular and neurochemical consequences of introduced genetic alterations constitute major advantages of investigating SNPs in inbred laboratory mouse strains. To investigate the behavioral and neurochemical consequences of a functional C1473G SNP in the mouse Tph2 gene, we generated congenic C57BL/6N mice homozygous for the Tph2 1473G allele. The Arg447 substitution in the TPH2 enzyme resulted in a significant reduction of the brain serotonin (5-HT) in vivo synthesis rate. Despite decreased 5-HT synthesis, we could detect neither a reduction of brain region-specific 5-HT concentrations nor changes in baseline and stress-induced 5-HT release using a microdialysis approach. However, using a [35S]GTP-γ-S binding assay and 5-HT1A receptor autoradiography, a functional desensitization of 5-HT1A autoreceptors could be identified. Furthermore, behavioral analysis revealed a distinct anxiety phenotype in homozygous Tph2 1473G mice, which could be reversed with chronic escitalopram treatment. Alterations in depressive-like behavior could not be detected under baseline conditions or after chronic mild stress. These findings provide evidence for an involvement of functional Tph2 polymorphisms in anxiety-related behaviors, which are likely not caused directly by alterations in 5-HT content or release but are rather due to compensatory changes during development involving functional desensitization of 5-HT1A autoreceptors. PMID:22491354

5HT2A receptor blockade in dorsomedial striatum reduces repetitive behaviors in BTBR mice.

PubMed

Amodeo, D A; Rivera, E; Cook, E H; Sweeney, J A; Ragozzino, M E

2017-03-01

Restricted and repetitive behaviors are a defining feature of autism, which can be expressed as a cognitive flexibility deficit or stereotyped, motor behaviors. There is limited knowledge about the underlying neuropathophysiology contributing to these behaviors. Previous findings suggest that central 5HT 2A receptor activity is altered in autism, while recent work indicates that systemic 5HT 2A receptor antagonist treatment reduces repetitive behaviors in an idiopathic model of autism. 5HT 2A receptors are expressed in the orbitofrontal cortex and striatum. These two regions have been shown to be altered in autism. The present study investigated whether 5HT 2A receptor blockade in the dorsomedial striatum or orbitofrontal cortex in the BTBR mouse strain, an idiopathic model of autism, affects the phenotype related to restricted and repetitive behaviors. Microinfusion of the 5HT 2A receptor antagonist, M100907 into the dorsomedial striatum alleviated a reversal learning impairment and attenuated grooming behavior. M100907 infusion into the orbitofrontal cortex increased perseveration during reversal learning and potentiated grooming. These findings suggest that increased 5HT 2A receptor activity in the dorsomedial striatum may contribute to behavioral inflexibility and stereotyped behaviors in the BTBR mouse. 5HT 2A receptor signaling in the orbitofrontal cortex may be critical for inhibiting a previously learned response during reversal learning and expression of stereotyped behavior. The present results suggest which brain areas exhibit abnormalities underlying repetitive behaviors in an idiopathic mouse model of autism, as well as which brain areas systemic treatment with M100907 may principally act on in BTBR mice to attenuate repetitive behaviors. © 2016 John Wiley & Sons Ltd and International Behavioural and Neural Genetics Society.

Selective Modulation of K+ Channel Kv7.4 Significantly Affects the Excitability of DRN 5-HT Neurons.

PubMed

Zhao, Chen; Su, Min; Wang, Yingzi; Li, Xinmeng; Zhang, Yongxue; Du, Xiaona; Zhang, Hailin

2017-01-01

The serotonin (5-HT) system originating in the dorsal raphe nucleus (DRN) is implicated in various mood- and emotion-related disorders, such as anxiety, fear and stress. Abnormal activity of DRN 5-HT neurons is the key factor in the development of these disorders. Here, we describe a crucial role for the Kv7.4 potassium channel in modulating DRN 5-HT neuronal excitability. We demonstrate that Kv7.4 is selectively expressed in 5-HT neurons of the DRN. Using selective Kv7.4 opener fasudil and Kv7.4 knock-out mice, we demonstrate that Kv7.4 is a potent modulator of DRN 5-HT neuronal excitability. Furthermore, we demonstrate that the cellular redox signaling mechanism is involved in this 5-HT activation of Kv7.4. The current study suggests a new strategy for treating psychiatric disorders related to altered activity of DRN 5-HT neurons using K + channel modulators.

Selective Modulation of K+ Channel Kv7.4 Significantly Affects the Excitability of DRN 5-HT Neurons

PubMed Central

Zhao, Chen; Su, Min; Wang, Yingzi; Li, Xinmeng; Zhang, Yongxue; Du, Xiaona; Zhang, Hailin

2017-01-01

The serotonin (5-HT) system originating in the dorsal raphe nucleus (DRN) is implicated in various mood- and emotion-related disorders, such as anxiety, fear and stress. Abnormal activity of DRN 5-HT neurons is the key factor in the development of these disorders. Here, we describe a crucial role for the Kv7.4 potassium channel in modulating DRN 5-HT neuronal excitability. We demonstrate that Kv7.4 is selectively expressed in 5-HT neurons of the DRN. Using selective Kv7.4 opener fasudil and Kv7.4 knock-out mice, we demonstrate that Kv7.4 is a potent modulator of DRN 5-HT neuronal excitability. Furthermore, we demonstrate that the cellular redox signaling mechanism is involved in this 5-HT activation of Kv7.4. The current study suggests a new strategy for treating psychiatric disorders related to altered activity of DRN 5-HT neurons using K+ channel modulators. PMID:29311835

CRF receptor 1 antagonism and brain distribution of active components contribute to the ameliorative effect of rikkunshito on stress-induced anorexia

PubMed Central

Mogami, Sachiko; Sadakane, Chiharu; Nahata, Miwa; Mizuhara, Yasuharu; Yamada, Chihiro; Hattori, Tomohisa; Takeda, Hiroshi

2016-01-01

Rikkunshito (RKT), a Kampo medicine, has been reported to show an ameliorative effect on sustained hypophagia after novelty stress exposure in aged mice through serotonin 2C receptor (5-HT2CR) antagonism. We aimed to determine (1) whether the activation of anorexigenic neurons, corticotropin-releasing factor (CRF), and pro-opiomelanocortin (POMC) neurons, is involved in the initiation of hypophagia induced by novelty stress in aged mice; (2) whether the ameliorative effect of RKT is associated with CRF and POMC neurons and downstream signal transduction; and (3) the plasma and brain distribution of the active components of RKT. The administration of RKT or 5-HT2CR, CRF receptor 1 (CRFR1), and melanocortin-4 receptor antagonists significantly restored the decreased food intake observed in aged male C57BL/6 mice in the early stage after novelty stress exposure. Seven components of RKT exhibited antagonistic activity against CRFR1. Hesperetin and isoliquiritigenin, which showed antagonistic effects against both CRFR1 and 5-HT2CR, were distributed in the plasma and brain of male Sprague-Dawley rats after a single oral administration of RKT. In conclusion, the ameliorative effect of RKT in this model is assumed to be at least partly due to brain-distributed active components possessing 5-HT2CR and CRFR1 antagonistic activities. PMID:27273195

CRF receptor 1 antagonism and brain distribution of active components contribute to the ameliorative effect of rikkunshito on stress-induced anorexia.

PubMed

Mogami, Sachiko; Sadakane, Chiharu; Nahata, Miwa; Mizuhara, Yasuharu; Yamada, Chihiro; Hattori, Tomohisa; Takeda, Hiroshi

2016-06-08

Rikkunshito (RKT), a Kampo medicine, has been reported to show an ameliorative effect on sustained hypophagia after novelty stress exposure in aged mice through serotonin 2C receptor (5-HT2CR) antagonism. We aimed to determine (1) whether the activation of anorexigenic neurons, corticotropin-releasing factor (CRF), and pro-opiomelanocortin (POMC) neurons, is involved in the initiation of hypophagia induced by novelty stress in aged mice; (2) whether the ameliorative effect of RKT is associated with CRF and POMC neurons and downstream signal transduction; and (3) the plasma and brain distribution of the active components of RKT. The administration of RKT or 5-HT2CR, CRF receptor 1 (CRFR1), and melanocortin-4 receptor antagonists significantly restored the decreased food intake observed in aged male C57BL/6 mice in the early stage after novelty stress exposure. Seven components of RKT exhibited antagonistic activity against CRFR1. Hesperetin and isoliquiritigenin, which showed antagonistic effects against both CRFR1 and 5-HT2CR, were distributed in the plasma and brain of male Sprague-Dawley rats after a single oral administration of RKT. In conclusion, the ameliorative effect of RKT in this model is assumed to be at least partly due to brain-distributed active components possessing 5-HT2CR and CRFR1 antagonistic activities.

Fisetin exerts antihyperalgesic effect in a mouse model of neuropathic pain: engagement of spinal serotonergic system

PubMed Central

Zhao, Xin; Wang, Chuang; Cui, Wu-Geng; Ma, Qing; Zhou, Wen-Hua

2015-01-01

Fisetin, a natural flavonoid, has been shown in our previous studies to exert antidepressant-like effect. As antidepressant drugs are clinically used to treat chronic neuropathic pain, this work aimed to investigate the potential antinociceptive efficacies of fisetin against neuropathic pain and explore mechanism(s). We subjected mice to chronic constriction injury (CCI) by loosely ligating the sciatic nerves, and Hargreaves test or von Frey test was used to assess thermal hyperalgesia or mechanical allodynia, respectively. Chronic fisetin treatment (5, 15 or 45 mg/kg, p.o.) ameliorated thermal hyperalgesia (but not mechanical allodynia) in CCI mice, concomitant with escalated levels of spinal monoamines and suppressed monoamine oxidase (MAO)-A activity. The antihyperalgesic action of fisetin was abolished by chemical depletion of spinal serotonin (5-HT) but potentiated by co-treatment with 5-HTP, a precursor of 5-HT. Moreover, intraperitoneal (i.p.) or intrathecal (i.t.) co-treatment with 5-HT7 receptor antagonist SB-258719 completely abrogated fisetin's antihyperalgesia. These findings confirm that chronic fisetin treatment exerts antinociceptive effect on thermal hyperalgesia in neuropathic mice, with spinal serotonergic system (coupled with 5-HT7) being critically involved. Of special benefit, fisetin attenuated co-morbidly behavioral symptoms of depression and anxiety (evaluated in forced swim test, novelty suppressed feeding test and light-dark test) evoked by neuropathic pain. PMID:25761874

Chronic treatment with LY341495 decreases 5-HT2A receptor binding and hallucinogenic effects of LSD in mice

PubMed Central

Moreno, José L.; Holloway, Terrell; Rayannavar, Vinayak; Sealfon, Stuart C.; González-Maeso, Javier

2013-01-01

Hallucinogenic drugs, such as lysergic acid diethylamide (LSD), mescaline and psilocybin, alter perception and cognitive processes. All hallucinogenic drugs have in common a high affinity for the serotonin 5-HT2A receptor. Metabotropic glutamate 2/3 (mGlu2/3) receptor ligands show efficacy in modulating the cellular and behavioral responses induced by hallucinogenic drugs. Here, we explored the effect of chronic treatment with the mGlu2/3 receptor antagonist 2S-2-amino-2-(1S,2S-2-carboxycyclopropan-1-yl)-3-(xanth-9-yl)-propionic acid (LY341495) on the hallucinogenic-like effects induced by LSD (0.24 mg/kg). Mice were chronically (21 days) treated with LY341495 (1.5 mg/kg), or vehicle, and experiments were carried out one day after the last injection. Chronic treatment with LY341495 down-regulated [3H]ketanserin binding in somatosensory cortex of wild-type, but not mGlu2 knockout (KO), mice. Head-twitch behavior, and expression of c-fos, egr-1 and egr-2, which are responses induced by hallucinogenic 5-HT2A agonists, were found to be significantly decreased by chronic treatment with LY341495. These findings suggest that repeated blockade of the mGlu2 receptor by LY341495 results in reduced 5-HT2A receptor-dependent hallucinogenic effects of LSD. PMID:23333599

Chronic fluoxetine treatment accelerates kindling epileptogenesis in mice independently of 5-HT2A receptors.

PubMed

Li, Crystal; Silva, Juliana; Ozturk, Ezgi; Dezsi, Gabriella; O'Brien, Terence J; Renoir, Thibault; Jones, Nigel C

2018-06-01

Patients with epilepsy often have mood disorders, and these are commonly treated with antidepressant drugs. Although these drugs are often successful in mitigating depressive symptoms, how they affect the epileptogenic processes has been little studied. Recent evidence has demonstrated that treatment with selective serotonin reuptake inhibitor (SSRI) antidepressant drugs adversely promotes epileptogenesis, which may be of great concern considering the number of patients exposed to these drugs. This study investigated 5-HT 2A receptor signaling as a potential mechanism driving the pro-epileptogenic effects of the prototypical SSRI fluoxetine. Male homozygous 5-HT 2A receptor knockout mice or wild-type littermates (n = 9-14/group) were treated with continuous fluoxetine (10 mg kg -1 d -1 , sc) or vehicle and subjected to electrical kindling of the amygdala. Compared to vehicle, fluoxetine treatment accelerated kindling epileptogenesis (P < .001), but there was no effect of genotype (P = .75), or any treatment x genotype interaction observed (P = .90). Of interest, fluoxetine treatment increased afterdischarge thresholds in both genotypes (P = .007). We conclude that treatment with fluoxetine promotes epileptogenesis in mice, but this effect is not mediated by 5-HT 2A receptors. This suggests that antidepressants may accelerate the onset of acquired epilepsy in patients who have experienced epileptogenic cerebral insults. Wiley Periodicals, Inc. © 2018 International League Against Epilepsy.

Selective deletion of forebrain glycogen synthase kinase 3β reveals a central role in serotonin-sensitive anxiety and social behaviour

PubMed Central

Latapy, Camille; Rioux, Véronique; Guitton, Matthieu J.; Beaulieu, Jean-Martin

2012-01-01

Serotonin (5-HT) neurotransmission is thought to underlie mental illnesses, such as bipolar disorder, depression, autism and schizophrenia. Independent studies have indicated that 5-HT or drugs acting on 5-HT neurotransmission regulate the serine/threonine kinase glycogen synthase kinase 3β (GSK3β). Furthermore, GSK3β inhibition rescues behavioural abnormalities in 5-HT-deficient mice with a loss-of-function mutation equivalent to the human variant (R441H) of tryptophan hydroxylase 2. In an effort to define neuroanatomical correlates of GSK3β activity in the regulation of behaviour, we generated CamKIIcre-floxGSK3β mice in which the gsk3b gene is postnatally inactivated in forebrain pyramidal neurons. Behavioural characterization showed that suppression of GSK3β in these brain areas has anxiolytic and pro-social effects. However, while a global reduction of GSK2β expression reduced responsiveness to amphetamine and increased resilience to social defeat, these behavioural effects were not found in CamKIIcre-floxGSK3β mice. These findings demonstrate a dissociation of behavioural effects related to GSK3 inhibition, with forebrain GSK3β being involved in the regulation of anxiety and sociability while social preference, resilience and responsiveness to psychostimulants would involve a function of this kinase in subcortical areas such as the hippocampus and striatum. PMID:22826345

Oral ofloxacin therapy of Pseudomonas aeruginosa sepsis in mice after irradiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brook, I.; Ledney, G.D.

Death subsequent to whole-body irradiation is associated with gram-negative bacterial sepsis. The effect of oral therapy with the new quinolone ofloxacin for orally acquired Pseudomonas aeruginosa infection was tested in B6D2F1 mice exposed to 7.0 Gy of bilateral radiation from 60Co. A dose of 10(7) organisms was given orally 2 days after irradiation, and therapy was started 1 day later. Only 4 of 20 untreated mice (20%) survived for at least 30 days compared with 19 of 20 mice (95%) treated with ofloxacin (P less than 0.005). P. aeruginosa was isolated from the livers of 21 to 28 untreated micemore » (75%), compared with only 2 of 30 treated mice (P less than 0.005). Ofloxacin reduced colonization of the ileum by P. aeruginosa; 24 of 28 untreated mice (86%) harbored the organisms, compared with only 5 of 30 (17%) with ofloxacin (P less than 0.005). This experiment was replicated twice, and similar results were obtained. These data illustrate the efficacy of the quinolone ofloxacin for oral therapy of orally acquired P. aeruginosa infection in irradiated hosts.« less

Heijiangdan ointment relieves oxidative stress from radiation dermatitis induced by (60)Co γ-ray in mice.

PubMed

Yang, Lin; Yu, Ming-wei; Wang, Xiao-min; Zhang, Yi; Yang, Guo-wang; Luo, Xiao-qin; Peng, Rui-yun; Gao, Ya-bing; Zhao, Li; Wang, Li-feng

2016-02-01

To investigate the effects of Heijiangdan Ointment ( HJD) on oxidative stress in (60)Co γ-ray radiation-induced dermatitis in mice. Female Wistar mice with grade 4 radiation dermatitis induced by (60)Co γ-rays were randomly divided into four groups (n=12 per group); the HJD-treated, recombinant human epidermal growth factor (rhEGF)-treated, Trolox-treated, and untreated groups, along with a negative control group. On the 11th and 21st days after treatment, 6 mice in each group were chosen for evaluation. The levels of superoxide dismutase (SOD), malondialdehyde (MDA), and lactate dehydrogenase (LDH) were detected using spectrophotometric methods. The fibroblast mitochondria were observed by transmission electron microscopy (TEM). The expressions of fibroblast growth factor 2 (FGF-2) and transforming growth factor β1 (TGF-β1) were analyzed by western blot. Compared with the untreated group, the levels of SOD, MDA and LDH, on the 11th and 21st days after treatment showed significant difference (P<0.05). TEM analysis indicated that fibroblast mitochondria in the untreated group exhibited swelling and the cristae appeared fractured, while in the HJD group, the swelling of mitochondria was limited and the rough endoplasmic reticulum appeared more relaxed. The expressions of FGF-2 and TGF-β1 increased in the untreated group compared with the negative control group (P<0.05). After treatment, the expression of FGF-2, rhEGF and Trolox in the HJD group were significantly increased compared with the untreated group (P<0.05), or compared with the negative control group (P<0.05). The expression of TGF-β1 showed significant difference between untreated and negative control groups (P<0.05). HJD and Trolox increased the level of TGF-β1 and the difference was marked as compared with the untreated and negative control groups (P<0.05). HJD relieves oxidative stress-induced injury, increases the antioxidant activity, mitigates the fibroblast mitochondrial damage, up-regulates the expression of growth factor, and promotes mitochondrial repair in mice.

Chronic exercise improves repeated restraint stress-induced anxiety and depression through 5HT1A receptor and cAMP signaling in hippocampus.

PubMed

Kim, Mun Hee; Leem, Yea Hyun

2014-03-01

Mood disorders such as anxiety and depression are prevalent psychiatric illness, but the role of 5HT1A in the anti-depressive effects of exercise has been rarely known yet. We investigated whether long-term exercise affected a depressive-like behavior and a hippocampal 5HT1A receptor-mediated cAMP/PKA/CREB signaling in depression mice model. To induce depressive behaviors, mice were subjected to 14 consecutive days of restraint stress (2 hours/day). Depression-like behaviors were measured by forced swimming test (TST), and anxiety-like behavior was assessed by elevated plus maze (EPM). Treadmill exercise was performed with 19 m/min for 60 min/day, 5 days/week from weeks 0 to 8. Restraint stress was started at week 6 week and ended at week 8. To elucidate the role of 5HT1A in depression, the immunoreactivities of 5HT1A were detected in hippocampus using immunohistochemical technique. Chronic/repeated restraint stress induced behavioral anxiety and depression, such as reduced time and entries in open arms in EPM and enhanced immobility time in FST. These anxiety and depressive behaviors were ameliorated by chronic exercise. Also, these behavioral changes were concurrent with the deficit of 5HT1A and cAMP/PKA/CREB cascade in hippocampus, which was coped with chronic exercise. These results suggest that chronic exercise may improve the disturbance of hippocampal 5HT1A-regulated cAMP/PKA/CREB signaling in a depressed brain, thereby exerting an antidepressive action.

The effects of brain serotonin deficiency on behavioural disinhibition and anxiety-like behaviour following mild early life stress.

PubMed

Sachs, Benjamin D; Rodriguiz, Ramona M; Siesser, William B; Kenan, Alexander; Royer, Elizabeth L; Jacobsen, Jacob P R; Wetsel, William C; Caron, Marc G

2013-10-01

Aberrant serotonin (5-HT) signalling and exposure to early life stress have both been suggested to play a role in anxiety- and impulsivity-related behaviours. However, whether congenital 5-HT deficiency × early life stress interactions influence the development of anxiety- or impulsivity-like behaviour has not been established. Here, we examined the effects of early life maternal separation (MS) stress on anxiety-like behaviour and behavioural disinhibition, a type of impulsivity-like behaviour, in wild-type (WT) and tryptophan hydroxylase 2 (Tph2) knock-in (Tph2KI) mice, which exhibit ~60-80% reductions in the levels of brain 5-HT due to a R439H mutation in Tph2. We also investigated the effects of 5-HT deficiency and early life stress on adult hippocampal neurogenesis, plasma corticosterone levels and several signal transduction pathways in the amygdala. We demonstrate that MS slightly increases anxiety-like behaviour in WT mice and induces behavioural disinhibition in Tph2KI animals. We also demonstrate that MS leads to a slight decrease in cell proliferation within the hippocampus and potentiates corticosterone responses to acute stress, but these effects are not affected by brain 5-HT deficiency. However, we show that 5-HT deficiency leads to significant alterations in SGK-1 and GSK3β signalling and NMDA receptor expression in the amygdala in response to MS. Together, these findings support a potential role for 5-HT-dependent signalling in the amygdala in regulating the long-term effects of early life stress on anxiety-like behaviour and behavioural disinhibition.

Making bread with sourdough improves iron bioavailability from reconstituted fortified wheat flour in mice.

PubMed

Chaoui, Asmaa; Faid, Mohamed; Belahsen, Rekia

2006-01-01

This study aimed to evaluate the effect of a diet prepared with traditional sourdough (TS) on iron status. Levels of blood hemoglobin (Hb), Hematocrite (Ht), serum ferritin and serum iron as well as excreted iron were determined in three groups of mice fed with: TS bread (TS group), baking yeast bread (BY group) or bread with no starters (control group), respectively. The results show that the levels of Hb, Ht, ferritin and iron were significantly higher in the TS compared to the BY and control groups. Also a significant decrease in the excreted iron levels was observed in the mice fed with TS compared to the others dietary groups. In conclusion, the study results indicate an improvement of iron status indicators in mice when they were fed sourdough bread as compared to baking yeast bread and bread with no starters.

Comparison of exendin-4 on beta-cell replication in mouse and human islet grafts.

PubMed

Tian, Lei; Gao, Jie; Weng, Guangbin; Yi, Huimin; Tian, Bole; O'Brien, Timothy D; Guo, Zhiguang

2011-08-01

Exendin-4 can stimulate β-cell replication in mice. Whether it can stimulate β-cell replication in human islet grafts remains unknown. Therefore, we compared the effects of exendin-4 on β-cell replication in mouse and human islet grafts. Islets, isolated from mouse and human donors at different ages, were transplanted into diabetic mice and/or diabetic nude mice that were given bromodeoxyuridine (BrdU) with or without exendin-4. At 4 weeks post-transplantation, islet grafts were removed for insulin and BrdU staining and quantification of insulin(+)/BrdU(+) cells. Although diabetes was reversed in all mice transplanting syngeneic mouse islets from young or old donors, normoglycemia was achieved significantly faster in exendin-4 treated mice. Mouse islet grafts in exendin-4 treated mice had significantly more insulin(+)/BrdU(+) β cells than in untreated mice (P < 0.01). Human islet grafts from ≤22-year-old donors had more insulin(+)/BrdU(+) β cells in exendin-4 treated mice than that in untreated mice (P < 0.01). However, human islet grafts from ≥35-year-old donors contained few insulin(+)/BrdU(+) β cells in exendin-4 treated or untreated mice. Our data demonstrated that the capacity for β-cell replication in mouse and human islet grafts is different with and without exendin-4 treatment and indicated that GLP-1 agonists can stimulate β-cell replication in human islets from young donors. © 2011 The Authors. Transplant International © 2011 European Society for Organ Transplantation.

Effects of swim stress and fluoxetine on 5-HT1A receptor gene expression and monoamine metabolism in the rat brain regions.

PubMed

Shishkina, G T; Kalinina, T S; Dygalo, N N

2012-07-01

Changes in gene expression of the brain serotonin (5-HT) 1A receptors may be important for the development and ameliorating depression, however identification of specific stimuli that activate or reduce the receptor transcriptional activity is far from complete. In the present study, the forced swim test (FST) exposure, the first stress session of which is already sufficient to induce behavioral despair in rats, significantly increased 5-HT1A receptor mRNA levels in the brainstem, frontal cortex, and hippocampus at 24 h. In the brainstem and frontal cortex, the elevation in the receptor gene expression after the second forced swim session was not affected following chronic administration of fluoxetine, while in the cortex, both control and FST values were significantly reduced in fluoxetine-treated rats. In contrast to untreated rats, no increase in hippocampal 5-HT1A receptor mRNA was observed in response to FST in rats chronically treated with fluoxetine. Metabolism of 5-HT (5-HIAA/5-HT) in the brainstem was significantly decreased by fluoxetine and further reduced by swim stress, showing a certain degree of independence of these changes on 5-HT1A receptor gene expression that was increased in this brain region only after the FST, but not after fluoxetine. FST exposure also decreased the brainstem dopamine metabolism, which was unexpectedly positively correlated with 5-HT1A receptor mRNA levels in the frontal cortex. Together, these data suggest that the effects of the forced swim stress as well as fluoxetine involve brain region-dependent alterations in 5-HT1A receptor gene transcription, some of which may be interrelated with concomitant changes in catecholamine metabolism.

Inhibiting MicroRNA-503 and MicroRNA-181d with Losartan Ameliorates Diabetic Nephropathy in KKAy Mice.

PubMed

Zhu, XinWang; Zhang, CongXiao; Fan, QiuLing; Liu, XiaoDan; Yang, Gang; Jiang, Yi; Wang, LiNing

2016-10-22

BACKGROUND Diabetic nephropathy (DN) is the most lethal diabetic microvascular complication; it is a major cause of renal failure, and an increasingly globally prominent healthcare problem. MATERIAL AND METHODS To identify susceptible microRNAs for the pathogenesis of DN and the targets of losartan treatment, microRNA arrays were employed to survey the glomerular microRNA expression profiles of KKAy mice treated with or without losartan. KKAy mice were assigned to either a losartan-treated group or a non-treatment group, with C57BL/6 mice used as a normal control. Twelve weeks after treatment, glomeruli from the mice were isolated. MicroRNA expression profiles were analyzed using microRNA arrays. Real-time PCR was used to confirm the results. RESULTS Losartan treatment improved albuminuria and the pathological lesions of KKAy mice. The expression of 10 microRNAs was higher, and the expression of 12 microRNAs was lower in the glomeruli of the KKAy untreated mice than that of the CL57BL/6 mice. The expression of 4 microRNAs was down-regulated in the glomeruli of the KKAy losartan-treated mice compared to that of the untreated mice. The expression of miRNA-503 and miRNA-181d was apparently higher in the glomeruli of the KKAy untreated mice, and was inhibited by losartan treatment. CONCLUSIONS The over-expression of miR-503 and miR-181d in glomeruli of KKAy mice may be responsible for the pathogenesis of DN and are potential therapeutic targets for DN.

Behavioral effects of chronic fluoxetine in BALB/cJ mice do not require adult hippocampal neurogenesis or the serotonin 1A receptor.

PubMed

Holick, Kerri A; Lee, Daniel C; Hen, René; Dulawa, Stephanie C

2008-01-01

We previously reported that chronic, but not subchronic, treatment with the selective serotonin reuptake inhibitor (SSRI) fluoxetine altered behavior in the forced swimming test (FST) in BALB/cJ mice. We now use this model to investigate mechanisms underlying the delayed onset of the behavioral response to antidepressants, specifically (1) adult hippocampal neurogenesis and (2) expression of the 5-HT1A receptor. Here, we show data validating this model of chronic antidepressant action. We found the FST to be selectively responsive to chronic administration of the SSRI fluoxetine (18 mg/kg/day) and the tricyclic antidepressant desipramine (20 mg/kg/day), but not to the antipsychotic haloperidol (1 mg/kg/day) in BALB/cJ mice. The behavioral effects of fluoxetine emerged by 12 days of treatment, and were affected neither by ablation of progenitor cells of the hippocampus nor by genetic deletion of the 5-HT1A receptor. The effect of fluoxetine in the BALB/cJ mice was also neurogenesis-independent in the novelty-induced hypophagia test. We also found that chronic fluoxetine does not induce an increase in cell proliferation or the number of young neurons as measured by BrdU and doublecortin immunolabeling, respectively, in BALB/cJ mice. These data are in contrast to our previous report using a different strain of mice (129SvEvTac). In conclusion, we find that BALB/cJ mice show a robust response to chronic SSRI treatment in the FST, which is not mediated by an increase in new neurons in the hippocampus, and does not require the 5-HT1A receptor. These findings suggest that SSRIs can produce antidepressant-like effects via distinct mechanisms in different mouse strains.

Validation and pharmacological characterisation of MK-801-induced locomotor hyperactivity in BALB/C mice as an assay for detection of novel antipsychotics.

PubMed

Bradford, Andrea M; Savage, Kevin M; Jones, Declan N C; Kalinichev, Mikhail

2010-10-01

We evaluated locomotor hyperactivity induced in BALB/C mice by an N-methyl-D-aspartate receptor antagonist MK-801 as an assay for the detection of antipsychotic drugs. We assessed the effects of antipsychotic drugs to validate the assay (study 1), selective dopamine and serotonin ligands for pharmacological characterisation of the model (study 2) and a number of compounds with efficacy in models of schizophrenia to understand the predictive validity of the model (study 3). Adult males (n  = 9/group) were pretreated with a test compound, habituated to locomotor activity cages before receiving MK-801 (0.32 mg/kg) and activity recorded for a further 75 or 120 min. In study 1, we tested haloperidol, clozapine, olanzapine, risperidone, ziprasidone, aripiprazole, sertindole and quetiapine. In study 2, we tested SCH23390 (D(1) antagonist), sulpiride (D(2)/D(3) antagonist), raclopride (D(2)/D(3) antagonist), SB-277011 (D(3) antagonist), L-745,870 (D(4) antagonist), WAY100635 (5-HT(1A) antagonist), 8-OH-DPAT (5-HT(1A) agonist), ketanserin (5-HT(2A)/5-HT(2C) antagonist) and SB-242084 (5-HT(2C) antagonist). In study 3, we tested xanomeline (M(1)/M(4) receptor agonist), LY379268 (mGluR2/3 receptor agonist), diazepam (GABA(A) modulator) and thioperamide (H(3) receptor antagonist). All antipsychotics suppressed MK-801-induced hyperactivity in a dose-dependent and specific manner. The effects of antipsychotics appear to be mediated via dopamine D(1), D(2) and 5-HT(2) receptors. Xanomeline, LY379268 and diazepam were active in this assay while thioperamide was not. MK-801-induced hyperactivity in BALB/C mice model of positive symptoms has shown predictive validity with novel compounds acing at M(1)/M(4), mGluR2/3 and GABA(A) receptors and can be used as a screening assay for detection of novel pharmacotherapies targeting those receptors.

NOD1 downregulates intestinal serotonin transporter and interacts with other pattern recognition receptors.

PubMed

Layunta, Elena; Latorre, Eva; Forcén, Raquel; Grasa, Laura; Plaza, Miguel A; Arias, Maykel; Alcalde, Ana I; Mesonero, José E

2018-05-01

Serotonin (5-HT) is an essential gastrointestinal modulator whose effects regulate the intestinal physiology. 5-HT effects depend on extracellular 5-HT bioavailability, which is controlled by the serotonin transporter (SERT) expressed in both the apical and basolateral membranes of enterocytes. SERT is a critical target for regulating 5-HT levels and consequently, modulating the intestinal physiology. The deregulation of innate immune receptors has been extensively studied in inflammatory bowel diseases (IBD), where an exacerbated defense response to commensal microbiota is observed. Interestingly, many innate immune receptors seem to affect the serotonergic system, demonstrating a new way in which microbiota could modulate the intestinal physiology. Therefore, our aim was to analyze the effects of NOD1 activation on SERT function, as well as NOD1's interaction with other immune receptors such as TLR2 and TLR4. Our results showed that NOD1 activation inhibits SERT activity and expression in Caco-2/TC7 cells through the extracellular signal-regulated kinase (ERK) signaling pathway. A negative feedback between 5-HT and NOD1 expression was also described. The results showed that TLR2 and TLR4 activation seems to regulate NOD1 expression in Caco-2/TC7 cells. To assess the extend of cross-talk between NOD1 and TLRs, NOD1 expression was measured in the intestinal tract (ileum and colon) of wild type mice and mice with individual knockouts of TLR2, and TLR4 as well as double knockout TLR2/TLR4 mice. Hence, we demonstrate that NOD1 acts on the serotonergic system decreasing SERT activity and molecular expression. Additionally, NOD1 expression seems to be modulated by 5-HT and other immune receptors as TLR2 and TLR4. This study could clarify the relation between both the intestinal serotonergic system and innate immune system, and their implications in intestinal inflammation. © 2017 Wiley Periodicals, Inc.

Involvement of N-methyl-d-aspartate receptors in the antidepressant-like effect of 5-hydroxytryptamine 3 antagonists in mouse forced swimming test and tail suspension test.

PubMed

Kordjazy, Nastaran; Haj-Mirzaian, Arya; Amiri, Shayan; Ostadhadi, Sattar; Amini-Khoei, Hossein; Dehpour, Ahmad Reza

2016-02-01

Recent evidence indicates that 5-hydroxytryptamine 3 (5-HT3) antagonists such as ondansetron and tropisetron exert positive behavioral effects in animal models of depression. Due to the ionotropic nature of 5-HT3 and N-methyl-d-aspartate (NMDA) receptors, plus their contribution to the pathophysiology of depression, we investigated the possible role of NMDA receptors in the antidepressant-like effect of 5-HT3 receptor antagonists in male mice. In order to evaluate the animals' behavior in response to different treatments, we performed open-field test (OFT), forced swimming test (FST), and tail-suspension test (TST), which are considered as valid tasks for measuring locomotor activity and depressive-like behaviors in mice. Our data revealed that intraperitoneal (i.p.) administration of tropisetron (5, 10, and 30mg/kg) and ondansetron (0.01, and 0.1μg/kg) significantly decreased the immobility time in FST and TST. Also, co-administration of subeffective doses of tropisetron (1mg/kg, i.p.) or ondansetron (0.001μg/kg, i.p.) with subeffective doses of NMDA receptor antagonists, ketamine (1mg/kg, i.p.), MK-801 (0.05mg/kg, i.p.) and magnesium sulfate (10mg/kg, i.p.) resulted in a reduced immobility time both in FST and TST. The subeffective dose of NMDA (NMDA receptor agonist, 75mg/kg, i.p.) abolished the effects of 5-HT3 antagonists in FST and TST, further supporting the presumed interaction between 5-HT3 and NMDA receptors. These treatments did not affect the locomotor behavior of animals in OFT. Finally, the results of our study suggest that the positive effects of 5-HT3 antagonists on the coping behavior of mice in FST and TST are at least partly mediated through NMDA receptors participation. Copyright © 2015 Elsevier Inc. All rights reserved.

Preclinical evaluation of destruxin B as a novel Wnt signaling target suppressing proliferation and metastasis of colorectal cancer using non-invasive bioluminescence imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yeh, Chi-Tai; Center of Excellence for Cancer Research, Taipei Medical University, Taipei, Taiwan; Department of Surgery, Taipei Medical University-Shuang Ho Hospital, Taipei, Taiwan

2012-05-15

In continuation to our studies toward the identification of direct anti-cancer targets, here we showed that destruxin B (DB) from Metarhizium anisopliae suppressed the proliferation and induced cell cycle arrest in human colorectal cancer (CRC) HT29, SW480 and HCT116 cells. Additionally, DB induced apoptosis in HT29 cells by decreased expression level of anti-apoptotic proteins Bcl-2 and Bcl-xL while increased pro-apoptotic Bax. On the other hand, DB attenuated Wnt-signaling by downregulation of β-catenin, Tcf4 and β-catenin/Tcf4 transcriptional activity, concomitantly with decreased expression of β-catenin target genes cyclin D1, c-myc and survivin. Furthermore, DB affected the migratory and invasive ability of HT29more » cells through suppressed MMPs-2 and -9 enzymatic activities. We also found that DB targeted the MAPK and/or PI3K/Akt pathway by reduced expression of Akt, IKK-α, JNK, NF-κB, c-Jun and c-Fos while increased that of IκBα. Finally, we demonstrated that DB inhibited tumorigenesis in HT29 xenograft mice using non-invasive bioluminescence technique. Consistently, tumor samples from DB-treated mice demonstrated suppressed expression of β-catenin, cyclin D1, survivin, and endothelial marker CD31 while increased caspase-3 expression. Collectively, our data supports DB as an inhibitor of Wnt/β-catenin/Tcf signaling pathway that may be beneficial in the CRC management. Highlights: ► Destruxin B (DB) inhibited colorectal cancer cells growth and induced apoptosis. ► MAPK and/or PI3K/Akt cascade cooperates in DB induced apoptosis. ► DB affected the migratory and invasive ability of HT29 cells through MMP-9. ► DB attenuated Wnt-signaling components β-catenin, Tcf4. ► DB attenuated cyclin D1, c-myc, survivin and tumorigenesis in HT29 xenograft mice.« less

Elevated Serotonin Interacts with Angiotensin-II to Result in Altered Valve Interstitial Cell Contractility and Remodeling.

PubMed

Perez, Jessica; Diaz, Nancy; Tandon, Ishita; Plate, Rachel; Martindale, Christopher; Balachandran, Kartik

2018-06-01

While the valvulopathic effects of serotonin (5HT) and angiotensin-II (Ang-II) individually are known, it was not clear how 5HT and Ang-II might interact, specifically in the context of the mechanobiological responses due to altered valve mechanics potentiated by these molecules. In this context, the hypothesis of this study was that increased serotonin levels would result in accelerated progression toward disease in the presence of angiotensin-II-induced hypertension. C57/BL6 J mice were divided into four groups and subcutaneously implanted with osmotic pumps containing: PBS (control), 5HT (2.5 ng/kg/min), Ang-II (400 ng/kg/min), and 5HT + Ang-II (combination). Blood pressure was monitored using the tail cuff method. Echocardiography was performed on the mice before surgery and every week thereafter to assess ejection fraction. After three weeks, the mice were sacrificed and their hearts excised, embedded and sectioned for analysis of the aortic valves via histology and immunohistochemistry. In separate experiments, porcine valve interstitial cells (VICs) were directly stimulated with 5HT (10 -7  M), Ang-II (100 nM) or both and assayed for cellular contractility, cytoskeletal organization and collagen remodeling. After three weeks, average systolic blood pressure was significantly increased in the 5HT, Ang-II and combination groups compared to control. Echocardiographic analysis demonstrated significantly reduced ejection fraction in Ang-II and the combination groups. H&E staining demonstrated thicker leaflets in the combination groups, suggesting a more aggressive remodeling process. Picrosirius red staining and image analysis suggested that the Ang-II and combination groups had the largest proportion of thicker collagen fibers. VIC orientation, cellular contractility and collagen gene expression was highest for the 5HT + Ang-II combination treatment compared to all other groups. Overall, our results suggest that 5HT and Ang-II interact to result in significantly detrimental alteration of function and remodeling in the valve.

Effects of antipsychotics and reference monoaminergic ligands on marble burying behavior in mice.

PubMed

Bruins Slot, Liesbeth A; Bardin, Laurent; Auclair, Agnès L; Depoortere, Ronan; Newman-Tancredi, Adrian

2008-03-01

Antipsychotics constitute efficacious augmenting agents in the treatment of anxiety disorders, including refractory obsessive-compulsive disorder. We examined the effects of 36 compounds, including typical, atypical and novel antipsychotics with dual dopamine D2/5-hydroxytryptamine 1A (D2/5-HT1A) actions on marble burying behavior in mice, a putative preclinical test for anxiety disorders. One hour after drug administration, male NMRI mice were placed individually in cages containing 20 marbles, and the total number of marbles buried after 30 min was counted. The selective serotonin reuptake inhibitors, citalopram (2.5-40 mg/kg), fluoxetine (2.5-10 mg/kg) and the benzodiazepine diazepam (2.5-10 mg/kg), reduced the number of buried marbles. The atypical antipsychotic, clozapine (0.16-10 mg/kg), but not its congener olanzapine, was effective in this test. Haloperidol, a typical antipsychotic, also reduced the number of buried marbles, albeit not in a dose-dependent manner. The atypical risperidone was partially active (0.16-0.63 mg/kg), as was the benzamide derivative, amisulpride, albeit at high (10-40 mg/kg) doses. Among the 'third-generation' antipsychotics possessing combined D2/5-HT1A properties, bifeprunox was active at 0.0025 mg/kg, whereas SLV313 and aripiprazole were active only at the highest doses (2.5 and 10 mg/kg, respectively). SSR181507, F15063 and the antidyskinetic agent, sarizotan, were without any effect. Among a series of receptor subtype-selective ligands, only the 5-HT1A agonist, (+)-8-OH-DPAT (0.63-2.5 mg/kg) and the 5-HT2A/2B/2C antagonist, ritanserin (0.63-2.5 mg/kg) were active. Among novel antipsychotics with dual D2/5-HT1A properties, only bifeprunox was able to potently reduce the number of buried marbles. Inhibition of marble burying behavior may result from the interplay of several receptor systems, including 5-HT2 receptor blockade, dopamine D2 partial agonism and serotonin 5-HT1A agonism.

Early-life antibiotic treatment enhances the pathogenicity of CD4+ T cells during intestinal inflammation.

PubMed

Scheer, Sebastian; Medina, Tiago S; Murison, Alex; Taves, Matthew D; Antignano, Frann; Chenery, Alistair; Soma, Kiran K; Perona-Wright, Georgia; Lupien, Mathieu; Arrowsmith, Cheryl H; De Carvalho, Daniel D; Zaph, Colby

2017-04-01

The incidence of inflammatory bowel diseases (IBDs) has steadily increased in recent decades-a phenomenon that cannot be explained by genetic mutations alone. Other factors, including the composition of the intestinal microbiome, are potentially important contributors to the increased occurrence of this group of diseases. Previous reports have shown a correlation between early-life antibiotic (Abx) treatment and an increased incidence of IBD. In this report, we investigated the effects of early-life Abx treatments on the pathogenicity of CD4 + T cells using an experimental T cell transfer model of IBD. Our results show that CD4 + T cells isolated from adult mice that had been treated with Abx during gestation and in early life induced a faster onset of IBD in Rag1 -deficient mice compared with CD4 + T cells of untreated mice. Ex vivo functional analyses of IBD-inducing CD4 + T cells did not show significant differences in their immunologic potential ex vivo, despite their in vivo phenotype. However, genome-wide gene-expression analysis revealed that these cells displayed dysregulated expression of genes associated with cell-cycle regulation, metabolism, and cellular stress. Analysis of Abx-treated CD4 + T cell donors showed systemically elevated levels of the stress hormone corticosterone throughout life compared with untreated donors. The cohousing of Abx-treated mice with untreated mice decreased serum corticosterone, and a consequent transfer of the cells from cohoused mice into Rag1 -deficient mice restored the onset and severity of disease to that of untreated animals. Thus, our results suggest that early-life Abx treatment results in a stress response with high levels of corticosterone that influences CD4 + T cell function. © Society for Leukocyte Biology.

Serotonin- and Dopamine-Related Gene Expression in db/db Mice Islets and in MIN6 β-Cells Treated with Palmitate and Oleate.

PubMed

Cataldo, L R; Mizgier, M L; Busso, D; Olmos, P; Galgani, J E; Valenzuela, R; Mezzano, D; Aranda, E; Cortés, V A; Santos, J L

2016-01-01

High circulating nonesterified fatty acids (NEFAs) concentration, often reported in diabetes, leads to impaired glucose-stimulated insulin secretion (GSIS) through not yet well-defined mechanisms. Serotonin and dopamine might contribute to NEFA-dependent β-cell dysfunction, since extracellular signal of these monoamines decreases GSIS. Moreover, palmitate-treated β-cells may enhance the expression of the serotonin receptor Htr2c, affecting insulin secretion. Additionally, the expression of monoamine-oxidase type B (Maob) seems to be lower in islets from humans and mice with diabetes compared to nondiabetic islets, which may lead to increased monoamine concentrations. We assessed the expression of serotonin- and dopamine-related genes in islets from db/db and wild-type (WT) mice. In addition, the effect of palmitate and oleate on the expression of such genes, 5HT content, and GSIS in MIN6 β-cell was determined. Lower Maob expression was found in islets from db/db versus WT mice and in MIN6 β-cells in response to palmitate and oleate treatment compared to vehicle. Reduced 5HT content and impaired GSIS in response to palmitate (-25%; p < 0.0001) and oleate (-43%; p < 0.0001) were detected in MIN6 β-cells. In conclusion, known defects of GSIS in islets from db/db mice and MIN6 β-cells treated with NEFAs are accompanied by reduced Maob expression and reduced 5HT content.

Hippocampal 5-HT1A Receptor and Spatial Learning and Memory

PubMed Central

Glikmann-Johnston, Yifat; Saling, Michael M.; Reutens, David C.; Stout, Julie C.

2015-01-01

Spatial cognition is fundamental for survival in the topographically complex environments inhabited by humans and other animals. The hippocampus, which has a central role in spatial cognition, is characterized by high concentration of serotonin (5-hydroxytryptamine; 5-HT) receptor binding sites, particularly of the 1A receptor (5-HT1A) subtype. This review highlights converging evidence for the role of hippocampal 5-HT1A receptors in spatial learning and memory. We consider studies showing that activation or blockade of the 5-HT1A receptors using agonists or antagonists, respectively, lead to changes in spatial learning and memory. For example, pharmacological manipulation to induce 5-HT release, or to block 5-HT uptake, have indicated that increased extracellular 5-HT concentrations maintain or improve memory performance. In contrast, reduced levels of 5-HT have been shown to impair spatial memory. Furthermore, the lack of 5-HT1A receptor subtype in single gene knockout mice is specifically associated with spatial memory impairments. These findings, along with evidence from recent cognitive imaging studies using positron emission tomography (PET) with 5-HT1A receptor ligands, and studies of individual genetic variance in 5-HT1A receptor availability, strongly suggests that 5-HT, mediated by the 5-HT1A receptor subtype, plays a key role in spatial learning and memory. PMID:26696889

[The efficacy of autocatalytic casapse-3 driven by human telomerase reverse transcriptase promoter on human ovarian carcinoma].

PubMed

Song, Yue; Shen, Keng; Yu, Jing-rong

2007-11-06

To construct recombinant adenoviral vector expressing autocatalysis caspase-3 driven by human telomerase reverse transcriptase promoter (hTERTp), and investigate its antitumor effect on ovarian cancer in vitro and in vivo. Recombinant adenovirus expressing autocatalytic caspase-3 (rev-csapase-3) driven by hTERTp, AdHT-rev-casp3, was constructed. Ad-rev-casp3 expressing rev-caspase-3 driven by cytomegalovirus promoter (CMVp) was used as a positive control. hTERT positive human ovarian cancer cells of the line AO and hTERT-negative human umbilical venous endothelial cells (HUVECs) were cultured and transfected with AdHT-rev-casp3, Ad-rev-casp3, or Ad-EGFG expressing enhanced green fluorescent protein as control group. Western blotting, Cell Counting Kit (CCK-8), flow cytometry, and TUNEL were used to detect the expression of p17, active subunit of caspase-3, and p85, a poly ADP-ribose polymerase (PARP) cleavage fragment, and they were also used to measure the cell survival rate and apoptotic rate. Western blotting was used to detect the expression of active caspase-3 and its substrate PARP in the AO cells and HUVECs. Twenty nude BALB/c mice were inoculated subcutaneously with AO cells to establish subcutaneous tumor models, when the tumor grew to the volume of 150 mm3 the rats were divided into 4 equal groups to undergo intra-tumor injection of AdHT-rev-casp3, Ad-rev-casp3, Ad-EGFG, and phosphate-buffered saline (PBS) respectively, the survival rate tumor inhibition rate was observed, 72 days later the mice were killed with their livers and tumors taken out, and Western blotting was used to detect the expression of active caspase-3. Another 40 mice underwent intraperitoneal injection of AO cells to establish intraperitoneal transplanted tumor models, 21 days later the rats were divided into 4 equal groups to be injected intraperitoneally with AdHT-rev-casp3, Ad-rev-casp3, Ad-EGFG, or PBS, the survival rate was observed, and the blood levels of alanine transaminase (ALT) and aspartate transaminase (AST) were detected. Following the administration of AdHT-rev-casp3, active caspase-3 protein was significantly expressed, and the levels of p17 and p85 expressions were significantly elevated in AO cells, while no expressions of p17 and p85 was observed in HUVEC. In contrast, both AO and HUVEC expressed high levels of p17 and p85 protein after administrations of Ad-rev-casp3. AdHT-rev-casp3 dose-dependently killed the hTERT positive AO cells, however, showed no killing effect on the hTERT-negative HUVEC cells; whereas Ad-rev-casp3 was cytotoxic independent of the hTERT status of the cells. The killing effect of Ad-rev-casp3 was stronger than that of AdHT-rev-casp3. Treated with AdHT-rev-cap3 the expression levels of the caspase-3 fragment p17 and PARP cleavage fragment p85 of the AO cells were significantly higher than those before the treatment, however, the expression levels of p17 and p85 were both weaker than those of the AO cells treated with Ad-rev-casp-3. Though treated with AdHT-rev-casp-3, there was still no remarkable expression of p17 and p85 in the HUVECs, however, rather high protein expression levels of p17 and p85 was shown. After treatment with AdHT-rev-casp3 remarkable expression of active caspase-3 was seen in the tumor collected from the mouse body, but not in the liver; however, high caspase-3 expression level was shown in both the liver and tumor after the treatment of Ad-rev-casp-3. 53 days after treatment the tumor suppression rate of the AdHT-rev-casp3 and ad-rev-casp-3 groups were 60% and 70% respectively, both significantly higher than that of the control group. The survival rates of the mice treated with AdHT-rev-casp3 and Ad-rev-casp-3 were both significantly longer than that of the PBS group; however the survival rate of the Ad-rev-casp-3 group was longer than that of the AdHT-rev-casp3 group. The serum ALT and AST levels were not significantly elevated in the AdHT-rev-casp3-treated mice, whereas 7-9-times that before treatment in the Ad-rev-casp3-treated mice. Recombinant adenovirus AdHT-rev-casp3 expressing rev-caspase-3 driven by hTERTp effectively causes cell apoptosis targeting tumor, significantly suppresses tumor growth and prolongs the mouse survival duration, with mild liver toxicity.

Killing effects of Huaier Granule combined with DC-CIK on nude mice transplanted with colon carcinoma cell line.

PubMed

Sun, Wen-Wen; Dou, Jin-Xia; Zhang, Lin; Qiao, Li-Kui; Shen, Na; Zhao, Qiang; Gao, Wen-Yuan

2017-07-11

This study aims to compare the efficacy of different treatments for nude mice transplanted with HT-29 colon carcinoma cell line. BalB/C nude mice were transplanted with HT-29 colon carcinoma cell line and randomly divided into four groups, with 5 mice in each group: blank control group, DC-CIK group, Huaier Granule group, and Huaier Granule group combined with DC-CIK group (combined treatment group). For DC-CIK group and combined treatment group, 1×106 DC-CIK cells were injected via the tail vein 4 days after transplantation. The injection was performed twice weekly for a total of 2 weeks. For Huaier Granule group and combined treatment group, Huaier Granule was administered at the dose of 20 g/60 g, by dissolving 20 g of Huaier granules in 600 ml of pure water. Intragastric administration of 0.2 ml of granules was performed once daily for 3 weeks. For the blank control group, equal volume of normal saline was given. Tumor size and body weight of nude mice were measured every 2 days during the 3-week treatment. The mice were sacrificed at the end of treatment to harvest tumors. Key genes of the signaling pathway were detected by RT-PCR. At the end of treatment, mice in combined treatment group, DC-CIK group and Huaier Granule group remained stable emotionally with normal mobility and water and food intake. However, in the blank control group, the mobility was restricted starting from the third week and the mice were on the verge of dying. The expression of PI3KR1, Akt, Wnt1, CTTNB1, Notch1, Notch2 and Notch3 genes were all downregulated significantly in the combined treatment group compared with DC-CIK group and Huaier Granule group (P<0.05). Therefore, the combined treatment of Huaier Granule combined with DC-CIK achieved the best effect in nude mice transplanted with HT-29 colon carcinoma cell line.

Regulation of intraocular pressure in mice: structural analysis of dopaminergic and serotonergic systems in response to cabergoline.

PubMed

Platania, Chiara Bianca Maria; Leggio, Gian Marco; Drago, Filippo; Salomone, Salvatore; Bucolo, Claudio

2013-11-01

Elevated intraocular pressure (IOP) is the main recognized risk factor of glaucoma. To investigate the contribution of dopaminergic and serotonergic systems in IOP regulation, we used cabergoline, a mixed dopamine and serotonin agonist, in C57BL/6J WT and dopamine D₃ receptor knock-out (D₃R⁻/⁻) mice with normal eye pressure or steroid-induced ocular hypertension. Furthermore, we studied the structural basis of the cabergoline-mediated activation of the dopaminergic and serotonergic systems by molecular modeling. Topical application of cabergoline, significantly decreased, in a dose-dependent manner, the intraocular pressure in WT mice, both in an ocular normotensive group (-9, -5 and -2 mmHg with 5%, 1%, and 0.1%, respectively) and an ocular hypertensive group, with a prolonged effect in this latter group. No change of intraocular pressure was observed after topical application of cabergoline in D₃R⁻/⁻ mice. We modeled and optimized, with molecular dynamics, structures of hD₃, h5HT(1A) and h5HT(2A-C) receptors; thereafter we carried out molecular docking of cabergoline. Docking revealed that binding of cabergoline into D₃ and 5HT(1A) receptors is associated with a better desolvation energy in comparison to 5HT(2A-C) binding. In conclusion, the present study support the hypothesis that dopaminergic system is pivotal to regulate IOP and that D₃R represents an intriguing target in the treatment of glaucoma. Furthermore, the structure-based computational approach adopted in this study is able to build and refine structure models of homologous dopaminergic and serotonergic receptors that may be of interest for structure-based drug discovery of ligands, with dopaminergic selectivity or with multi-pharmacological profile, potentially useful to treat optic neuropathies. Copyright © 2013 Elsevier Inc. All rights reserved.

Involvement of nitric oxide-cyclic guanosine monophosphate pathway in the antidepressant-like effect of tropisetron and ondansetron in mice forced swimming test and tail suspension test.

PubMed

Haj-Mirzaian, Arya; Kordjazy, Nastaran; Amiri, Shayan; Haj-Mirzaian, Arvin; Amini-Khoei, Hossien; Ostadhadi, Sattar; Dehpour, AhmadReza

2016-06-05

Antidepressant-like effects of 5-hydroxytryptamine subtype 3 (5-HT3) antagonists including tropisetron and ondansetron have been previously demonstrated in the literature. It was reported that stimulation of 5-HT3 receptors activate the nitric oxide-cyclic guanosine monophosphate (NO-cGMP) pathway, which is involved in regulation of behavioral and emotional functions. In our study, treating animals with tropisetron (5, 10, and 30mg/kg) and ondansetron (0.01 and 0.1µg/kg) significantly decreased the immobility time in forced swimming test (FST) and tail-suspension test (TST). Co-administration of subeffective doses of tropisetron (1mg/kg) and ondansetron (0.001µg/kg) with subeffective dose of l-NAME (10mg/kg, nonselective NO synthase (NOS) inhibitor) and 7-nitroindazole (25mg/kg, neural NOS inhibitor) exerted antidepressant-like effect in FST and TST, while aminoguanidine (50mg/kg, inducible NOS inhibitor) did not enhance the antidepressant-like effect of 5-HT3 antagonists. Besides, l-arginine (750mg/kg, NO precursor) and sildenafil (5mg/kg, phosphodiesterase inhibitor) suppressed the anti-immobility effect of 5-HT3 antagonists. None of the treatments altered the locomotor behavior of mice in open-field test. Also, hippocampal (but not cortical) nitrite level was significantly lower in tropisetron and ondansetron-treated mice compared with saline-injected mice. Also, co-administration of 7-nitroindazole with tropisetron or ondansetron caused a significant decrease in hippocampal nitrite levels. In conclusion, we suggest that antidepressant-like effect of tropisetron and ondansetron are partially mediated by modulation of NO-cGMP pathway. Copyright © 2016. Published by Elsevier B.V.

Effects of histamine and 5-hydroxytryptamine on the growth rate of xenografted human bronchogenic carcinomas.

PubMed

Sheehan, P F; Baker, T; Tutton, P J; Barkla, D H

1996-01-01

1. The influence of histamine and 5-hydroxytryptamine (5-HT) antagonists and agonists on the volume doubling times (Td) of human bronchogenic carcinomas propagated as s.c. xenografts in immunosuppressed mice was examined. 2. The H2-receptor antagonists, cimetidine and ranitidine, increased Td. 3. Treatment with the H2-receptor agonist, 4-methyl histamine, had no effect on Td. 4. Co-administration of 4-methyl histamine and cimetidine abolished the effects of cimetidine. 5. The 5-HT2-receptor antagonists, cinanserin and ketanserin, both increased Td. 6. Treatment with the 5-HT1/2-receptor agonist quipazine (0.1 mg/kg, reflecting 5-HT2 agonist activity) decreased Td, while a higher dose (10.0 mg/kg) had no effect. 7. The 5-HT1/2-receptor antagonist, methiothepin, decreased Td. 8. The 5-HT uptake inhibitor, fluoxetine, increased Td in one tumour line but not in another, while the 5-HT releaser/depletor, fenfluramine, increased Td. 9. Histamine may stimulate tumour growth through the histamine H2-receptor, while the dominant effect of 5-HT is 5-HT1-receptor inhibition. 10. Tumour growth in some bronchogenic carcinomas may involve 5-HT uptake mechanisms.

An immunohistochemistry-based study on aquaporin (AQP)-1, 3, 4, 5 and 8 in the parotid glands, submandibular glands and sublingual glands of Sjögren's syndrome mouse models chronically administered cevimeline.

PubMed

Nakamura, Moriyoshi; Saga, Tsuyoshi; Watanabe, Koichi; Takahashi, Nagahiro; Tabira, Yoko; Kusukawa, Jingo; Yamaki, Koh-Ichi

2013-01-01

Cevimeline is a muscarinic agonist that promotes saliva secretion and is used to treat Sjögren's syndrome (SS), an autoimmune disorder in which the exocrine glands that produce saliva are destroyed. Cevimeline is thought to affect the composition of saliva in part by regulating the localization of aquaporins (AQPs). In this study, we investigated the effects of chronic Cevimeline administration in the salivary glands of SS mice on the immunohistochemical localization of aquaporin (AQP)-1, 3, 4, 5 and 8. We used Cevimeline-untreated SS mice, treated SS mice, discontinued SS mice and untreated normal mice. AQP-5 was found in the apical and lateral membranes of acinar cells in the parotid and submandibular glands of cevimeline-treated SS mice and untreated normal mice. Saliva secretion and AQP-5 localization were sustained in SS mice who were chronically administered Cevimeline and at four weeks after discontinuation. Unlike AQP-5, the localization of AQP-1, 3, 4 and 8 were not affected by Cevimeline administration. Our findings demonstrated that administration of Cevimeline maintains the proper localization of AQP-5 in the acinar cells of the salivary gland, which may promote salivation in chronically treated SS mice. Clinically, this suggests that chronic Cevimeline administration may be useful therapeutically for SS patients suffering from a decrease in saliva secretion by improving the disordered AQP-5 localization.

Effect of treatment with interferon-gamma and concanavalin A on the course of infection of mice with Salmonella typhimurium strain LT-2

NASA Technical Reports Server (NTRS)

Gould, Cheryl L.; Sonnenfeld, Gerald

1987-01-01

The effect of pretreatment of mice with 34 units/day, for five days, of interferon-gamma (IFN-gamma) on the course of infection with LD50 of Salmonella typhimurium strain LT-2 was assessed, using two IFN preparations: (1) a hybridoma supernatant fluid containing concanavalin-A-induced IFN-gamma activity and (2) pure murine IFN-gamma produced by recombinant DNA technology. The hybridoma supernatant-treated Salmonella-infected mice were found to die faster than mice treated only with Salmonella. Pure murine IFN-gamma was found to protect infected mice significantly, with 95 percent of mice surviving LD50 infection. In contrast, the Salmonella-infected mice treated with hybridoma supernatant were found to die faster than the Salmonella-infected untreated controls. Mice treated with concanavalin A alone prior to infection with S. typhimurium died more quickly than the untreated infected controls, suggesting that contamination with concanavalin A had a detrimental effect on mice survival.

Serotonin controls initiation of locomotion and afferent modulation of coordination via 5-HT7 receptors in adult rats.

PubMed

Cabaj, Anna M; Majczyński, Henryk; Couto, Erika; Gardiner, Phillip F; Stecina, Katinka; Sławińska, Urszula; Jordan, Larry M

2017-01-01

Experiments on neonatal rodent spinal cord showed that serotonin (5-HT), acting via 5-HT 7 receptors, is required for initiation of locomotion and for controlling the action of interneurons responsible for inter- and intralimb coordination, but the importance of the 5-HT system in adult locomotion is not clear. Blockade of spinal 5-HT 7 receptors interfered with voluntary locomotion in adult rats and fictive locomotion in paralysed decerebrate rats with no afferent feedback, consistent with a requirement for activation of descending 5-HT neurons for production of locomotion. The direct control of coordinating interneurons by 5-HT 7 receptors observed in neonatal animals was not found during fictive locomotion, revealing a developmental shift from direct control of locomotor interneurons in neonates to control of afferent input from the moving limb in adults. An understanding of the afferents controlled by 5-HT during locomotion is required for optimal use of rehabilitation therapies involving the use of serotonergic drugs. Serotonergic pathways to the spinal cord are implicated in the control of locomotion based on studies using serotonin type 7 (5-HT 7 ) receptor agonists and antagonists and 5-HT 7 receptor knockout mice. Blockade of these receptors is thought to interfere with the activity of coordinating interneurons, a conclusion derived primarily from in vitro studies on isolated spinal cord of neonatal rats and mice. Developmental changes in the effects of serotonin (5-HT) on spinal neurons have recently been described, and there is increasing data on control of sensory input by 5-HT 7 receptors on dorsal root ganglion cells and/or dorsal horn neurons, leading us to determine the effects of 5-HT 7 receptor blockade on voluntary overground locomotion and on locomotion without afferent input from the moving limb (fictive locomotion) in adult animals. Intrathecal injections of the selective 5-HT 7 antagonist SB269970 in adult intact rats suppressed locomotion by partial paralysis of hindlimbs. This occurred without a direct effect on motoneurons as revealed by an investigation of reflex activity. The antagonist disrupted intra- and interlimb coordination during locomotion in all intact animals but not during fictive locomotion induced by stimulation of the mesencephalic locomotor region (MLR). MLR-evoked fictive locomotion was transiently blocked, then the amplitude and frequency of rhythmic activity were reduced by SB269970, consistent with the notion that the MLR activates 5-HT neurons, leading to excitation of central pattern generator neurons with 5-HT 7 receptors. Effects on coordination in adults required the presence of afferent input, suggesting a switch to 5-HT 7 receptor-mediated control of sensory pathways during development. © 2016 The Authors. The Journal of Physiology © 2016 The Physiological Society.

Serotonin controls initiation of locomotion and afferent modulation of coordination via 5‐HT7 receptors in adult rats

PubMed Central

Majczyński, Henryk; Couto, Erika; Gardiner, Phillip F.; Stecina, Katinka; Sławińska, Urszula

2016-01-01

Key points Experiments on neonatal rodent spinal cord showed that serotonin (5‐HT), acting via 5‐HT7 receptors, is required for initiation of locomotion and for controlling the action of interneurons responsible for inter‐ and intralimb coordination, but the importance of the 5‐HT system in adult locomotion is not clear.Blockade of spinal 5‐HT7 receptors interfered with voluntary locomotion in adult rats and fictive locomotion in paralysed decerebrate rats with no afferent feedback, consistent with a requirement for activation of descending 5‐HT neurons for production of locomotion.The direct control of coordinating interneurons by 5‐HT7 receptors observed in neonatal animals was not found during fictive locomotion, revealing a developmental shift from direct control of locomotor interneurons in neonates to control of afferent input from the moving limb in adults.An understanding of the afferents controlled by 5‐HT during locomotion is required for optimal use of rehabilitation therapies involving the use of serotonergic drugs. Abstract Serotonergic pathways to the spinal cord are implicated in the control of locomotion based on studies using serotonin type 7 (5‐HT7) receptor agonists and antagonists and 5‐HT7 receptor knockout mice. Blockade of these receptors is thought to interfere with the activity of coordinating interneurons, a conclusion derived primarily from in vitro studies on isolated spinal cord of neonatal rats and mice. Developmental changes in the effects of serotonin (5‐HT) on spinal neurons have recently been described, and there is increasing data on control of sensory input by 5‐HT7 receptors on dorsal root ganglion cells and/or dorsal horn neurons, leading us to determine the effects of 5‐HT7 receptor blockade on voluntary overground locomotion and on locomotion without afferent input from the moving limb (fictive locomotion) in adult animals. Intrathecal injections of the selective 5‐HT7 antagonist SB269970 in adult intact rats suppressed locomotion by partial paralysis of hindlimbs. This occurred without a direct effect on motoneurons as revealed by an investigation of reflex activity. The antagonist disrupted intra‐ and interlimb coordination during locomotion in all intact animals but not during fictive locomotion induced by stimulation of the mesencephalic locomotor region (MLR). MLR‐evoked fictive locomotion was transiently blocked, then the amplitude and frequency of rhythmic activity were reduced by SB269970, consistent with the notion that the MLR activates 5‐HT neurons, leading to excitation of central pattern generator neurons with 5‐HT7 receptors. Effects on coordination in adults required the presence of afferent input, suggesting a switch to 5‐HT7 receptor‐mediated control of sensory pathways during development. PMID:27393215

Molecular Mechanisms for Sweet-suppressing Effect of Gymnemic Acids*

PubMed Central

Sanematsu, Keisuke; Kusakabe, Yuko; Shigemura, Noriatsu; Hirokawa, Takatsugu; Nakamura, Seiji; Imoto, Toshiaki; Ninomiya, Yuzo

2014-01-01

Gymnemic acids are triterpene glycosides that selectively suppress taste responses to various sweet substances in humans but not in mice. This sweet-suppressing effect of gymnemic acids is diminished by rinsing the tongue with γ-cyclodextrin (γ-CD). However, little is known about the molecular mechanisms underlying the sweet-suppressing effect of gymnemic acids and the interaction between gymnemic acids versus sweet taste receptor and/or γ-CD. To investigate whether gymnemic acids directly interact with human (h) sweet receptor hT1R2 + hT1R3, we used the sweet receptor T1R2 + T1R3 assay in transiently transfected HEK293 cells. Similar to previous studies in humans and mice, gymnemic acids (100 μg/ml) inhibited the [Ca2+]i responses to sweet compounds in HEK293 cells heterologously expressing hT1R2 + hT1R3 but not in those expressing the mouse (m) sweet receptor mT1R2 + mT1R3. The effect of gymnemic acids rapidly disappeared after rinsing the HEK293 cells with γ-CD. Using mixed species pairings of human and mouse sweet receptor subunits and chimeras, we determined that the transmembrane domain of hT1R3 was mainly required for the sweet-suppressing effect of gymnemic acids. Directed mutagenesis in the transmembrane domain of hT1R3 revealed that the interaction site for gymnemic acids shared the amino acid residues that determined the sensitivity to another sweet antagonist, lactisole. Glucuronic acid, which is the common structure of gymnemic acids, also reduced sensitivity to sweet compounds. In our models, gymnemic acids were predicted to dock to a binding pocket within the transmembrane domain of hT1R3. PMID:25056955

Low-basicity 5-HT7 Receptor Agonists Synthesized Using the van Leusen Multicomponent Protocol.

PubMed

Hogendorf, Adam S; Hogendorf, Agata; Kurczab, Rafał; Satała, Grzegorz; Lenda, Tomasz; Walczak, Maria; Latacz, Gniewomir; Handzlik, Jadwiga; Kieć-Kononowicz, Katarzyna; Wierońska, Joanna M; Woźniak, Monika; Cieślik, Paulina; Bugno, Ryszard; Staroń, Jakub; Bojarski, Andrzej J

2017-05-04

A series of 5-aryl-1-alkylimidazole derivatives was synthesized using the van Leusen multicomponent reaction. The chemotype is the first example of low-basicity scaffolds exhibiting high affinity for 5-HT 7 receptor together with agonist function. The chosen lead compounds 3-(1-ethyl-1H-imidazol-5-yl)-5-iodo-1H-indole (AGH-107, 1o, K i 5-HT7  = 6 nM, EC 50  = 19 nM, 176-fold selectivity over 5-HT 1A R) and 1e (5-methoxy analogue, K i 5-HT7  = 30 nM, EC 50  = 60 nM) exhibited high selectivity over related CNS targets, high metabolic stability and low toxicity in HEK-293 and HepG2 cell cultures. A rapid absorption to the blood, high blood-brain barrier permeation and a very high peak concentration in the brain (C max  = 2723 ng/g) were found for 1o after i.p. (5 mg/kg) administration in mice. The compound was found active in novel object recognition test in mice, at 0.5, 1 and 5 mg/kg. Docking to 5-HT 7 R homology models indicated a plausible binding mode which explain the unusually high selectivity over the related CNS targets. Halogen bond formation between the most potent derivatives and the receptor is consistent with both the docking results and SAR. 5-Chlorine, bromine and iodine substitution resulted in a 13, 27 and 89-fold increase in binding affinities, respectively, and in enhanced 5-HT 1A R selectivity.

Social stress alters inhibitory synaptic input to distinct subpopulations of raphe serotonin neurons.

PubMed

Crawford, LaTasha K; Rahman, Shumaia F; Beck, Sheryl G

2013-01-16

Anxiety disorders are among the most prevalent psychiatric disorders, yet much is unknown about the underlying mechanisms. The dorsal raphe (DR) is at the crux of the anxiety-inducing effects of uncontrollable stress, a key component of models of anxiety. Though DR serotonin (5-HT) neurons play a prominent role, anxiety-associated changes in the physiology of 5-HT neurons remain poorly understood. A 5-day social defeat model of anxiety produced a multifaceted, anxious phenotype in intruder mice that included increased avoidance behavior in the open field test, increased stress-evoked grooming, and increased bladder and heart weights when compared to control mice. Intruders were further compared to controls using electrophysiology recordings conducted in midbrain slices wherein recordings targeted 5-HT neurons of the ventromedial (vmDR) and lateral wing (lwDR) subfields of the DR. Though defining membrane characteristics of 5-HT neurons were unchanged, γ-aminobutyric-acid-mediated (GABAergic) synaptic regulation of 5-HT neurons was altered in a topographically specific way. In the vmDR of intruders, there was a decrease in the frequency and amplitude of GABAergic spontaneous inhibitory postsynaptic currents (sIPSCs). However, in the lwDR, there was an increase in the strength of inhibitory signals due to slower sIPSC kinetics. Synaptic changes were selective for GABAergic input, as glutamatergic synaptic input was unchanged in intruders. The distinct inhibitory regulation of DR subfields provides a mechanism for increased 5-HT output in vmDR target regions and decreased 5-HT output in lwDR target regions, divergent responses to uncontrollable stress that have been reported in the literature but were previously poorly understood.

Novel Therapeutic Targets to Treat Social Behavior Deficits in Autism and Related Disorders

DTIC Science & Technology

2014-10-01

2a. Effects of D- 22 on [3H] serotonin uptake in vitro We have made good progress toward characterizing D- 22 ’s ability to block serotonin (5- HT ...b. Fig 4. [3H] 5- HT Synaptosomal Uptake Blockade by D- 22 and Fluoxetine. D- 22 is effective in vitro at µM concentrations...c. In vivo chronoamperometry to measure the effect of D- 22 on 5- HT uptake In BTBR mice, the effects of systemic (i.p.) injection of D- 22 on in vivo

Serotonin augmentation therapy by escitalopram has minimal effects on amyloid-β levels in early-stage Alzheimer's-like disease in mice.

PubMed

von Linstow, Christian Ulrich; Waider, Jonas; Grebing, Manuela; Metaxas, Athanasios; Lesch, Klaus Peter; Finsen, Bente

2017-09-12

Dysfunction of the serotonergic (5-HTergic) system has been implicated in the cognitive and behavioural symptoms of Alzheimer's disease (AD). Accumulation of toxic amyloid-β (Aβ) species is a hallmark of AD and an instigator of pathology. Serotonin (5-HT) augmentation therapy by treatment with selective serotonin reuptake inhibitors (SSRIs) in patients with AD has had mixed success in improving cognitive function, whereas SSRI administration to mice with AD-like disease has been shown to reduce Aβ pathology. The objective of this study was to investigate whether an increase in extracellular levels of 5-HT induced by chronic SSRI treatment reduces Aβ pathology and whether 5-HTergic deafferentation of the cerebral cortex could worsen Aβ pathology in the APP swe /PS1 ΔE9 (APP/PS1) mouse model of AD. We administered a therapeutic dose of the SSRI escitalopram (5 mg/kg/day) in the drinking water of 3-month-old APP/PS1 mice to increase levels of 5-HT, and we performed intracerebroventricular injections of the neurotoxin 5,7-dihydroxytryptamine (DHT) to remove 5-HTergic afferents. We validated the effectiveness of these interventions by serotonin transporter autoradiography (neocortex 79.7 ± 7.6%) and by high-performance liquid chromatography for 5-HT (neocortex 64% reduction). After 6 months of escitalopram treatment or housing after DHT-induced lesion, we evaluated brain tissue by mesoscale multiplex analysis and sections by IHC analysis. Amyloid-β-containing plaques had formed in the neocortex and hippocampus of 9-month-old APP/PS1 mice after 6 months of escitalopram treatment and 5-HTergic deafferentation. Unexpectedly, levels of insoluble Aβ42 were unaffected in the neocortex and hippocampus after both types of interventions. Levels of insoluble Aβ40 increased in the neocortex of SSRI-treated mice compared with those treated with vehicle control, but they were unaffected in the hippocampus. 5-HTergic deafferentation was without effect on the levels of insoluble/soluble Aβ42 and Aβ40 in both the neocortex and hippocampus. However, levels of soluble amyloid precursor protein α were reduced in the neocortex after 5-HTergic deafferentation. Because this study shows that modulation of the 5-HTergic system has either no effect or increases levels of insoluble/soluble Aβ42 and Aβ40 in the cerebral cortex of APP/PS1 mice, our observations do not support 5-HT augmentation therapy as a preventive strategy for reducing Aβ pathology.

Chronic treatment with LY341495 decreases 5-HT(2A) receptor binding and hallucinogenic effects of LSD in mice.

PubMed

Moreno, José L; Holloway, Terrell; Rayannavar, Vinayak; Sealfon, Stuart C; González-Maeso, Javier

2013-03-01

Hallucinogenic drugs, such as lysergic acid diethylamide (LSD), mescaline and psilocybin, alter perception and cognitive processes. All hallucinogenic drugs have in common a high affinity for the serotonin 5-HT(2A) receptor. Metabotropic glutamate 2/3 (mGlu2/3) receptor ligands show efficacy in modulating the cellular and behavioral responses induced by hallucinogenic drugs. Here, we explored the effect of chronic treatment with the mGlu2/3 receptor antagonist 2S-2-amino-2-(1S,2S-2-carboxycyclopropan-1-yl)-3-(xanth-9-yl)-propionic acid (LY341495) on the hallucinogenic-like effects induced by LSD (0.24mg/kg). Mice were chronically (21 days) treated with LY341495 (1.5mg/kg), or vehicle, and experiments were carried out one day after the last injection. Chronic treatment with LY341495 down-regulated [(3)H]ketanserin binding in somatosensory cortex of wild-type, but not mGlu2 knockout (KO), mice. Head-twitch behavior, and expression of c-fos, egr-1 and egr-2, which are responses induced by hallucinogenic 5-HT(2A) agonists, were found to be significantly decreased by chronic treatment with LY341495. These findings suggest that repeated blockade of the mGlu2 receptor by LY341495 results in reduced 5-HT(2A) receptor-dependent hallucinogenic effects of LSD. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Mirtazapine has a therapeutic potency in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced mice model of Parkinson's disease.

PubMed

Kadoguchi, Naoto; Okabe, Shinji; Yamamura, Yukio; Shono, Misaki; Fukano, Tatsuya; Tanabe, Akie; Yokoyama, Hironori; Kasahara, Jiro

2014-06-25

Mirtazapine, a noradrenergic and specific serotonergic antidepressant (NaSSA), shows multiple pharmacological actions such as inhibiting presynaptic α2 noradrenaline receptor (NAR) and selectively activating 5-hydroxytriptamine (5-HT) 1A receptor (5-HT1AR). Mirtazapine was also reported to increase dopamine release in the cortical neurons with 5-HT dependent manner. To examine whether mirtazapine has a therapeutic potency in Parkinson's disease (PD), we examined this compound in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated mice model of PD. Male C57BL/6 mice were subjected to MPTP treatment to establish a PD model. Mirtazapine was administered once a day for 3 days after MPTP treatment. MPTP-induced motor dysfunction, assessed by beam-walking and rota-rod tests, was significantly improved by administration of mirtazapine. Biochemical examinations by high performance liquid chromatography and western blot analysis suggested mirtazapine facilitated utilization of dopamine by increasing turnover and protein expression of transporters, without affecting on neurodegenerative process by MPTP. These therapeutic effects of mirtazapine were reduced by administration of WAY100635, an inhibitor for 5HT1AR, or of clonidine, a selective agonist for α2-NAR, or of prazosin, an inhibitor for α1-NAR, respectively. Our results showed mirtazapine had a therapeutic potency against PD in a mouse model. Because PD patients sometimes show depression together, it will be a useful drug for a future PD treatment.

Failed heart rate recovery at a critical age in 5-HT-deficient mice exposed to episodic anoxia: implications for SIDS

PubMed Central

Commons, Kathryn G.; Hewitt, Julie C.; Daubenspeck, John A.; Li, Aihua; Kinney, Hannah C.; Nattie, Eugene E.

2011-01-01

Mice deficient in the transcription factor Pet-1−/− have a ∼70% deficiency of brainstem serotonin [5-hydroxytryptamine (5-HT)] neurons and exhibit spontaneous bradycardias in room air at postnatal day (P)5 and P12 and delayed gasping in response to a single episode of anoxia at P4.5 and P9.5 (Cummings KJ, Li A, Deneris ES, Nattie EE. Am J Physiol Regul Integr Comp Physiol 298: R1333–R1342, 2010; and Erickson JT, Sposato BC. J Appl Physiol 106: 1785–1792, 2009). We hypothesized that at a critical age Pet-1−/− mice will fail to autoresuscitate during episodic anoxia, ultimately dying from a failure of gasping to restore heart rate (HR). We exposed P5, P8, and P12 Pet-1−/− mice and wild-type littermates (WT) to four 30-s episodes of anoxia (97% N2-3% CO2), separated by 5 min of room air. We observed excess mortality in Pet-1−/− only at P8: 43% of Pet-1−/− animals survived past the third episode of anoxia while ∼95% of WT survived all four episodes (P = 0.004). No deaths occurred at P5 and at P12, and one of six Pet-1−/− mice died after the fourth episode, while all WT animals survived. At P8, dying Pet-1−/− animals had delayed gasping, recovery of HR, and eupnea after the first two episodes of anoxia (P < 0.001 for each); death ultimately occurred when gasping failed to restore HR. Both high- and low-frequency components of HR variability were abnormally elevated in dying Pet-1−/− animals following the first episode of anoxia. Dying P8 Pet-1−/− animals had significantly fewer 5-HT neurons in the raphe magnus than surviving animals (P < 0.001). Our data indicate a critical developmental window at which a brainstem 5-HT deficiency increases the risk of death during episodes of anoxia. They may apply to the sudden infant death syndrome, which occurs at a critical age and is associated with 5-HT deficiency. PMID:21680874

RP5063, an atypical antipsychotic drug with a unique pharmacologic profile, improves declarative memory and psychosis in mouse models of schizophrenia.

PubMed

Rajagopal, Lakshmi; Kwon, Sunoh; Huang, Mei; Michael, Eric; Bhat, Laxminarayan; Cantillon, Marc; Meltzer, Herbert Y

2017-08-14

Various types of atypical antipsychotic drugs (AAPDs) modestly improve the cognitive impairment associated with schizophrenia (CIAS). RP5063 is an AAPD with a diverse and unique pharmacology, including partial agonism at dopamine (DA) D 2 , D 3 , D 4 , serotonin (5-HT) 1A , and 5-HT 2A receptors (Rs), full agonism at α 4 β 2 nicotinic acetylcholine (ACh)R (nAChR), and antagonism at 5-HT 2B , 5-HT 6 , and 5-HT 7 Rs. Most atypical APDs are 5-HT 2A inverse agonists. The efficacy of RP5063 in mouse models of psychosis and episodic memory were studied. RP5063 blocked acute phencyclidine (PCP)-as well as amphetamine-induced hyperactivity, indicating antipsychotic activity. Acute administration of RP5063 significantly reversed subchronic (sc)PCP-induced impairment in novel object recognition (NOR), a measure of episodic memory, but not reversal learning, a measure of executive function. Co-administration of a sub-effective dose (SED) of RP5063 with SEDs of a 5-HT 7 R antagonist, a 5-HT 1B R antagonist, a 5-HT 2A R inverse agonist, or an α 4 β 2 nAChR agonist, restored the ability of RP5063 to ameliorate the NOR deficit in scPCP mice. Pre-treatment with a 5-HT 1A R, a D 4 R, antagonist, but not an α 4 β 2 nAChR antagonist, blocked the ameliorating effect of RP5063. Further, co-administration of scRP5063 prior to each dose of PCP prevented the effect of PCP to produce a deficit in NOR for one week. RP5063, given to scPCP-treated mice for one week restored NOR for one week only. Acute administration of RP5063 significantly increased cortical DA efflux, which may be critical to some of its cognitive enhancing properties. These results indicate that RP5063, by itself, or as an adjunctive treatment has a multifaceted basis for improving some cognitive deficits associated with schizophrenia. Copyright © 2017. Published by Elsevier B.V.

Treatment with bindarit, an inhibitor of MCP-1 synthesis, protects mice against trinitrobenzene sulfonic acid-induced colitis.

PubMed

Bhatia, M; Landolfi, C; Basta, F; Bovi, G; Ramnath, R Devi; de Joannon, A Capezzone; Guglielmotti, A

2008-10-01

Chemokines play a fundamental role in trafficking and activation of leukocytes in colonic inflammation. We investigated the ability of bindarit, an inhibitor of monocyte chemoattractant protein-1 (MCP-1/CCL2) synthesis, to inhibit chemokine production by human intestinal epithelial cells (HT-29) and its effect in trinitro-benzene sulfonic acid (TNBS)-induced colitis in mice. HT-29 cells were incubated with bindarit in the presence of TNF-alpha/IFN-gamma and 24 h later supernatants were collected for MCP-1, IL-8 and RANTES measurement. A 1 mg enema of TNBS was given to BALB/c mice, and bindarit (100 mg/kg) was orally administered twice daily starting from two days before colitis induction. Weight loss, histology, and MCP-1 level and myeloperoxidase (MPO) activity in colon extracts were assessed. In HT-29 cells, bindarit concentration-dependently and selectively inhibited MCP-1 secretion (as well as mRNA expression) primed by TNF-alpha/IFN-gamma. Moreover treatment with bindarit reduced clinical and histopathological severity of TNBS-induced colitis. These effects were associated with significant inhibition of MCP-1 and MPO in colon extracts. Bindarit exhibits a potent bioactivity in reducing leukocyte infiltration, down-regulating MCP-1 synthesis, and preventing the development of severe colitis in a mice model of TNBS-induced colitis. These observations suggest a potential use of MCP-1 synthesis blockers in intestinal inflammation in humans.

Monoamine oxidase A and A/B knockout mice display autistic-like features

PubMed Central

Bortolato, Marco; Godar, Sean C.; Alzghoul, Loai; Zhang, Junlin; Darling, Ryan D.; Simpson, Kimberly L.; Bini, Valentina; Chen, Kevin; Wellman, Cara L.; Lin, Rick C. S.; Shih, Jean C.

2012-01-01

Converging lines of evidence show that a sizable subset of autism-spectrum disorders (ASDs) is characterized by increased blood levels of serotonin (5-hydroxytryptamine, 5-HT), yet the mechanistic link between these two phenomena remains unclear. The enzymatic degradation of brain 5-HT is mainly mediated by monoamine oxidase (MAO)A and, in the absence of this enzyme, by its cognate isoenzyme MAOB. MAOA and A/B knockout (KO) mice display high 5-HT levels, particularly during early developmental stages. Here we show that both mutant lines exhibit numerous behavioural hallmarks of ASDs, such as social and communication impairments, perseverative and stereotypical responses, behavioural inflexibility, as well as subtle tactile and motor deficits. Furthermore, both MAOA and A/B KO mice displayed neuropathological alterations reminiscent of typical ASD features, including reduced thickness of the corpus callosum, increased dendritic arborization of pyramidal neurons in the prefrontal cortex and disrupted microarchitecture of the cerebellum. The severity of repetitive responses and neuropathological aberrances was generally greater in MAOA/B KO animals. These findings suggest that the neurochemical imbalances induced by MAOAdeficiency (either by itself or in conjunction with lack of MAOB) may result in an array of abnormalities similar to those observed in ASDs. Thus, MAOA and A/B KO mice may afford valuable models to help elucidate the neurobiological bases of these disorders and related neurodevelopmental problems. PMID:22850464

Hormone therapy and clinical and surrogate cardiovascular endpoints in women with chronic kidney disease: a systematic review and meta-analysis.

PubMed

Ramesh, Sharanya; Mann, Michelle C; Holroyd-Leduc, Jayna M; Wilton, Stephen B; James, Matthew T; Seely, Ellen W; Ahmed, Sofia B

2016-09-01

Women with chronic kidney disease (CKD) experience kidney dysfunction-mediated premature menopause. The role of postmenopausal hormone therapy (HT) in this population is unclear. We sought to summarize current knowledge regarding use of postmenopausal HT and cardiovascular (CV) outcomes, and established surrogate measures of CV risk in women with CKD. This is a systematic review and meta-analysis of adult women with CKD. We searched electronic bibliographic databases (MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials) (inception to 2014 December), relevant conference proceedings, tables of contents of journals, and review articles. Randomized controlled trials and observational studies examining postmenopausal HT compared with either placebo or untreated control groups were included. The intervention of interest was postmenopausal HT, and the outcome measures were all-cause and CV mortality, nonfatal CV event (myocardial infarction, stroke), and surrogate measures of CV risk (serum lipids, blood pressure). Of 12,482 references retrieved, four randomized controlled trials and two cohort studies (N = 1,666 participants) were identified. No studies reported on CV outcomes or mortality. Compared with placebo, postmenopausal HT was associated with decreased low-density lipoprotein cholesterol (-13.2 mg/dL [95% CI, -23.32 to -3.00 mg/dL]), and increased high-density lipoprotein (8.73 mg/dL [95% CI, 4.72-12.73 mg/dL]) and total cholesterol (7.96 mg/dL [95% CI, 0.07-15.84 mg/dL]). No associations were observed between postmenopausal HT triglyceride levels and blood pressure. Studies examining the effect of postmenopausal HT on CV outcomes in women with CKD are lacking. Further prospective study of the role of postmenopausal HT in this high-risk group is required.

3,4-methylenedioxymethamphetamine self-administration is abolished in serotonin transporter knockout mice.

PubMed

Trigo, José Manuel; Renoir, Thibault; Lanfumey, Laurence; Hamon, Michel; Lesch, Klaus-Peter; Robledo, Patricia; Maldonado, Rafael

2007-09-15

The neurobiological mechanism underlying the reinforcing effects of 3,4-methylenedioxymethamphetamine (MDMA) remains unclear. The aim of the present study was to determine the contribution of the serotonin transporter (SERT) in MDMA self-administration behavior by using knockout (KO) mice deficient in SERT. Knockout mice and wild-type (WT) littermates were trained to acquire intravenous self-administration of MDMA (0, .03, .06, .125, and .25 mg/kg/infusion) on a fixed ratio 1 (FR1) schedule of reinforcement. Additional groups of mice were trained to obtain food and water to rule out operant responding impairments. Microdialysis studies were performed to evaluate dopamine (DA) and serotonin (5-HT) extracellular levels in the nucleus accumbens (NAC) and prefrontal cortex (PFC), respectively, after acute MDMA (10 mg/kg). None of the MDMA doses tested maintained intravenous self-administration in KO animals, whereas WT mice acquired responding for MDMA. Acquisition of operant responding for food and water was delayed in KO mice, but no differences between genotypes were observed on the last day of training. MDMA increased DA extracellular levels to a similar extent in the NAC of WT and KO mice. Conversely, extracellular concentrations of 5-HT in the PFC were increased following MDMA only in WT mice. These findings provide evidence for the specific involvement of SERT in MDMA reinforcing properties.

Adaptive Control of Dorsal Raphe by 5-HT4 in the Prefrontal Cortex Prevents Persistent Hypophagia following Stress.

PubMed

Jean, Alexandra; Laurent, Laetitia; Delaunay, Sabira; Doly, Stéphane; Dusticier, Nicole; Linden, David; Neve, Rachael; Maroteaux, Luc; Nieoullon, André; Compan, Valérie

2017-10-24

Transient reduced food intake (hypophagia) following high stress could have beneficial effects on longevity, but paradoxically, hypophagia can persist and become anorexia-like behavior. The neural underpinnings of stress-induced hypophagia and the mechanisms by which the brain prevents the transition from transient to persistent hypophagia remain undetermined. In this study, we report the involvement of a network governing goal-directed behavior (decision). This network consists of the ascending serotonergic inputs from the dorsal raphe nucleus (DR) to the medial prefrontal cortex (mPFC). Specifically, adult restoration of serotonin 4 receptor (5-HT 4 R) expression in the mPFC rescues hypophagia and specific molecular changes related to depression resistance in the DR (5-HT release elevation, 5-HT 1A receptor, and 5-HT transporter reductions) of stressed 5-HT 4 R knockout mice. The adult mPFC-5-HT 4 R knockdown mimics the null phenotypes. When mPFC-5-HT 4 Rs are overexpressed and DR-5-HT1ARs are blocked in the DR, hypophagia following stress persists, suggesting an antidepressant action of early anorexia. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Further investigation into the mechanism of tachykinin NK(2) receptor-triggered serotonin release from guinea-pig proximal colon.

PubMed

Kojima, Shu-Ichi; Ikeda, Masashi; Kamikawa, Yuichiro

2009-05-01

The effects of the monoamine oxidase A (MAO-A) inhibitor clorgyline, the L-type calcium-channel blocker nicardipine, the syntaxin inhibitor botulinum toxin type C, and the potent thiol-oxidant phenylarsine oxide (PAO) on the selective tachykinin NK(2)-receptor agonist [beta-Ala(8)]-neurokinin A(4-10) [betaAla-NKA-(4-10)]-evoked 5-hydroxytryptamine (5-HT) outflow from colonic enterochromaffin (EC) cells was investigated in vitro using isolated guinea-pig proximal colon. The betaAla-NKA-(4-10)-evoked outflow of 5-HT from clorgyline-treated colonic strips was markedly higher than that from clorgyline-untreated colonic strips. The betaAla-NKA-(4-10)-evoked 5-HT outflow from the clorgyline-treated colonic strips was sensitive to nicardipine or botulinum toxin type C. Moreover, PAO concentration-dependently suppressed the betaAla-NKA-(4-10)-evoked 5-HT outflow from the clorgyline-treated colonic strips. The suppressant action of PAO was reversed by the reducing agent dithiothrietol, but was not blocked by the protein tyrosine kinase inhibitor genistein. These results suggest that the tachykinin NK(2) receptor-triggered 5-HT release from guinea-pig colonic EC cells is mediated by syntaxin-related exocytosis mechanisms and that colonic mucosa MAO-A activity has the important function of modulating the tachykinin NK(2) receptor-triggered 5-HT release. It also appears that PAO-mediated sulfhydryl oxidation plays a role in modulating the tachykinin NK(2) receptor-triggered 5-HT release through a mechanism independent of inhibition of protein tyrosine phosphatase activity.

High-voltage electroencephalogram spindles in rats, aging and 5-HT2 antagonism.

PubMed

Moyanova, S; Kortenska, L; Kirov, R

1998-03-09

We examined the effects of serotonin-2 (5-hydroxytryptamine-2, 5-HT2) receptor antagonists on the so-called high-voltage spindles (HVS, electroencephalographic patterns, characterized by large amplitude rhythmic waves mainly in the alpha band), recorded from the frontal cortex of young, middle-aged and old freely-moving rats during waking immobility. The study was based on the assumption that the effects of 5-HT2 receptor antagonists on the HVS activity depend on the age of rats, because there is evidence for an age-related decrease in the 5-HT2 binding sites density. Four parameters of the electroencephalogram (EEG) were used to characterize the HVS activity: the square root-transformed EEG peak power in the alpha band, the frequency corresponding to this peak (both measured from the EEG power spectra using the fast Fourier transform), the HVS mean duration, and the HVS incidence (both measured from the EEG records). The EEG parameters were analyzed after i.p. administration of three 5-HT2 receptor antagonists: ketanserin, ritanserin and cyproheptadine. In young rats, the three drugs increased the alpha power, but did not change the alpha peak-corresponding frequency. Ketanserin and ritanserin did not change the HVS mean duration and HVS incidence, while cyproheptadine increased both these parameters in young rats. In middle-aged and old untreated rats, the HVS activity was significantly increased. The three 5-HT2 antagonists did not change the HVS activity in aged rats, which could be due to age-related suppression of the 5-HT2 receptor functions. Copyright 1998 Elsevier Science B.V.

Pharmacological rescue of Ras signaling, GluA1-dependent synaptic plasticity, and learning deficits in a fragile X model.

PubMed

Lim, Chae-Seok; Hoang, Elizabeth T; Viar, Kenneth E; Stornetta, Ruth L; Scott, Michael M; Zhu, J Julius

2014-02-01

Fragile X syndrome, caused by the loss of Fmr1 gene function, is the most common form of inherited mental retardation, with no effective treatment. Using a tractable animal model, we investigated mechanisms of action of a few FDA-approved psychoactive drugs that modestly benefit the cognitive performance in fragile X patients. Here we report that compounds activating serotonin (5HT) subtype 2B receptors (5HT2B-Rs) or dopamine (DA) subtype 1-like receptors (D1-Rs) and/or those inhibiting 5HT2A-Rs or D2-Rs moderately enhance Ras-PI3K/PKB signaling input, GluA1-dependent synaptic plasticity, and learning in Fmr1 knockout mice. Unexpectedly, combinations of these 5HT and DA compounds at low doses synergistically stimulate Ras-PI3K/PKB signal transduction and GluA1-dependent synaptic plasticity and remarkably restore normal learning in Fmr1 knockout mice without causing anxiety-related side effects. These findings suggest that properly dosed and combined FDA-approved psychoactive drugs may effectively treat the cognitive impairment associated with fragile X syndrome.

Functional changes in cerebral 5-hydroxytryptamine metabolism in the mouse induced by anticonvulsant drugs.

PubMed Central

Chadwick, D; Gorrod, J W; Jenner, P; Marsden, C D; Reynolds, E H

1978-01-01

1 Acute administration of clonazepam, diazepam, and diphenylhydantoin to mice elevated cerebral 5-hydroxytryptamine (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA); chronic administration had less effect. 2 Acute administration of clonazepam and diazepam but not diphenylhydantoin raised cerebral trytophan levels; chronic administration of clonazepam caused a smaller elevation of cerebral tryptophan but chronic administration of diazepam still caused a large rise in cerebral tryptophan. 3 Neither clonazepam nor diazepam caused induction of drug metabolizing enzymes on chronic administration but diphenylhydantoin had a marked effect. 4 These data suggest that the altered 5-HT metabolism caused by these compounds is unrelated to a common action on tryptophan levels, and that the reduced effect of clonazepam and diazepam on chronic administration cannot be attributed to increased metabolism of these compounds. 5 Clonazepam induced abnormal head movements in mice in a dose-dependent manner. Pretreatment of animals with tranylcypromine increased the intensity of movement, although pargyline was without effect. Similar effects were observed with diazepam and diphenylhydantoin, suggesting that the increase in cerebral 5-HT caused by these compounds is of functional significance in stimulating 5-HT receptors. PMID:620092

The Type 7 Serotonin Receptor, 5-HT7, Is Essential in the Mammary Gland for Regulation of Mammary Epithelial Structure and Function

PubMed Central

Pai, Vaibhav P.; Hernandez, Laura L.; Stull, Malinda A.; Horseman, Nelson D.

2015-01-01

Autocrine-paracrine activity of serotonin (5-hydroxytryptamine, 5-HT) is a crucial homeostatic parameter in mammary gland development during lactation and involution. Published studies suggested that the 5-HT7 receptor type was important for mediating several effects of 5-HT in the mammary epithelium. Here, using 5-HT7 receptor-null (HT7KO) mice we attempt to understand the role of this receptor in mediating 5-HT actions within the mammary gland. We demonstrate for the first time that HT7KO dams are inefficient at sustaining their pups. Histologically, the HT7KO mammary epithelium shows a significant deviation from the normal secretory epithelium in morphological architecture, reduced secretory vesicles, and numerous multinucleated epithelial cells with atypically displaced nuclei, during lactation. Mammary epithelial cells in HT7KO dams also display an inability to transition from lactation to involution as normally seen by transition from a columnar to a squamous cell configuration, along with alveolar cell apoptosis and cell shedding. Our results show that 5-HT7 is required for multiple actions of 5-HT in the mammary glands including core functions that contribute to changes in cell shape and cell turnover, as well as specialized secretory functions. Understanding these actions may provide new interventions to improve lactation performance and treat diseases such as mastitis and breast cancer. PMID:25664318

Effect of long-term treatment with melatonin on vascular markers of oxidative stress/inflammation and on the anticontractile activity of perivascular fat in aging mice.

PubMed

Agabiti-Rosei, Claudia; Favero, Gaia; De Ciuceis, Carolina; Rossini, Claudia; Porteri, Enzo; Rodella, Luigi Fabrizio; Franceschetti, Lorenzo; Maria Sarkar, Anna; Agabiti-Rosei, Enrico; Rizzoni, Damiano; Rezzani, Rita

2017-01-01

Some reports have suggested that inflammation in perivascular adipose tissue (PVAT) may be implicated in vascular dysfunction by causing the disappearance of an anticontractile effect. The aim of this study was to investigate the effects of chronic melatonin treatment on the functional responses of the small mesenteric arteries and on the expression of markers of inflammation/oxidative stress in the aortas of senescence-accelerated prone mice (SAMP8), a model of age-related vascular dysfunction. We investigated seven SAMP8 and seven control senescence-accelerated resistant mice (SAMR1) treated for 10 months with melatonin, as well as equal numbers of age-matched untreated SAMP8 and SAMR1. The mesenteric small resistance arteries were dissected and mounted on a wire myograph, and the concentration-response to norepinephrine was evaluated in vessels with intact PVAT and after the removal of the PVAT. The expression of markers of oxidative stress, inflammation and aging in the aortas was evaluated by immunostaining. In addition, the adiponectin content and the expression of adiponectin receptor 1 were evaluated in the visceral adipose tissue. In untreated SAMP8 mice, we observed an overexpression of oxidative stress and inflammatory markers in the vasculature compared with the controls. No anticontractile effect of the PVAT was observed in untreated SAMP8 mice. Long-term treatment of SAMP8 mice with melatonin increased the expression of some markers of vasoprotection, decreased oxidative stress and inflammation and restored the anticontractile effect of the PVAT. Decreased expression of adiponectin and adiponectin receptor 1 was also observed in visceral fat of untreated SAMP8, whereas a significant increase was observed after melatonin treatment.

Transient postnatal fluoxetine decreases brain concentrations of 20-HETE and 15-epi-LXA4, arachidonic acid metabolites in adult mice.

PubMed

Yuan, Zhi-Xin; Rapoport, Stanley I

2015-10-01

Transient postnatal exposure of rodents to the selective serotonin (5-HT) reuptake inhibitor (SSRI) fluoxetine alters behavior and brain 5-HT neurotransmission during adulthood, and also reduces brain arachidonic (ARA) metabolic consumption and protein level of the ARA metabolizing enzyme, cytochrome P4504A (CYP4A). Brain 20-hydroxyeicosatetraenoic acid (20-HETE), converted by CYP4A from ARA, will be reduced in adult mice treated transiently and postnatally with fluoxetine. Male mice pups were injected i.p. daily with fluoxetine (10mg/kg) or saline during P4-P21. At P90 their brain was high-energy microwaved and analyzed for 20-HETE and six other ARA metabolites by enzyme immunoassay. Postnatal fluoxetine vs. saline significantly decreased brain concentrations of 20-HETE (-70.3%) and 15-epi-lipoxin A4 (-60%) in adult mice, but did not change other eicosanoid concentrations. Behavioral changes in adult mice treated postnatally with fluoxetine may be related to reduced brain ARA metabolism involving CYP4A and 20-HETE formation. Published by Elsevier Ltd.

Interaction of brain 5-HT synthesis deficiency, chronic stress and sex differentially impact emotional behavior in Tph2 knockout mice.

PubMed

Gutknecht, Lise; Popp, Sandy; Waider, Jonas; Sommerlandt, Frank M J; Göppner, Corinna; Post, Antonia; Reif, Andreas; van den Hove, Daniel; Strekalova, Tatyana; Schmitt, Angelika; Colaςo, Maria B N; Sommer, Claudia; Palme, Rupert; Lesch, Klaus-Peter

2015-07-01

While brain serotonin (5-HT) function is implicated in gene-by-environment interaction (GxE) impacting the vulnerability-resilience continuum in neuropsychiatric disorders, it remains elusive how the interplay of altered 5-HT synthesis and environmental stressors is linked to failure in emotion regulation. Here, we investigated the effect of constitutively impaired 5-HT synthesis on behavioral and neuroendocrine responses to unpredictable chronic mild stress (CMS) using a mouse model of brain 5-HT deficiency resulting from targeted inactivation of the tryptophan hydroxylase-2 (Tph2) gene. Locomotor activity and anxiety- and depression-like behavior as well as conditioned fear responses were differentially affected by Tph2 genotype, sex, and CMS. Tph2 null mutants (Tph2(-/-)) displayed increased general metabolism, marginally reduced anxiety- and depression-like behavior but strikingly increased conditioned fear responses. Behavioral modifications were associated with sex-specific hypothalamic-pituitary-adrenocortical (HPA) system alterations as indicated by plasma corticosterone and fecal corticosterone metabolite concentrations. Tph2(-/-) males displayed increased impulsivity and high aggressiveness. Tph2(-/-) females displayed greater emotional reactivity to aversive conditions as reflected by changes in behaviors at baseline including increased freezing and decreased locomotion in novel environments. However, both Tph2(-/-) male and female mice were resilient to CMS-induced hyperlocomotion, while CMS intensified conditioned fear responses in a GxE-dependent manner. Our results indicate that 5-HT mediates behavioral responses to environmental adversity by facilitating the encoding of stress effects leading to increased vulnerability for negative emotionality.

Tumor-evoked hyperalgesia and sensitization of nociceptive dorsal horn neurons in a murine model of cancer pain

PubMed Central

Khasabov, Sergey G.; Hamamoto, Darryl T.; Harding-Rose, Catherine; Simone, Donald A.

2009-01-01

Pain associated with cancer, particularly when tumors metastasize to bone, is often severe and debilitating. Better understanding of the neurobiological mechanisms underlying cancer pain will likely lead to the development of more effective treatments. The aim of this study was to characterize changes in response properties of nociceptive dorsal horn neurons following implantation of fibrosarcoma cells into and around the calcaneus bone, an established model of cancer pain. Extracellular electrophysiological recordings were made from wide dynamic range (WDR) and high threshold (HT) dorsal horn neurons in mice with tumor-evoked hyperalgesia and control mice. WDR and HT neurons were examined for ongoing activity and responses to mechanical, heat, and cold stimuli applied to the plantar surface of the hind paw. Behavioral experiments showed that mice exhibited hyperalgesia to mechanical and heat stimuli applied to their tumor-bearing hind paw. WDR, but not HT, nociceptive dorsal horn neurons in tumor-bearing mice exhibited sensitization to mechanical, heat, and cold stimuli and may contribute to tumor-evoked hyperalgesia. Specifically, the proportion of WDR neurons that exhibited ongoing activity and their evoked discharge rates were greater in tumor-bearing than in control mice. In addition, WDR neurons exhibited lower response thresholds for mechanical and heat stimuli, and increased responses to suprathreshold mechanical, heat, and cold stimuli. Our findings show that sensitization of WDR neurons contribute to cancer pain and support the notion that the mechanisms underlying cancer pain differ from those that contribute to inflammatory and neuropathic pain. PMID:17935703

Antitumor Activities and Apoptosis-regulated Mechanisms of Fermented Barley Extract in the Transplantation Tumor Model of Human HT-29 Cells in Nude Mice.

PubMed

Yao, Fang; Zhang, Jia Yan; Xiao, Xiang; Dong, Ying; Zhou, Xing Hua

2017-01-01

A subcutaneous transplantation tumor model of human HT-29 cells was established in nude mice to study the anticarcinogenic activities and apoptosis-regulatory mechanistic effect of aqueous extract of fermented barley with Lactobacillus plantarum dy-1 (LFBE). HT-29 cells were transplanted via subcutaneous injection of 1 × 107cells into the right flank of each nude mouse. Then, nude mice were treated for 30 days with LFBE (high-dose 2 g·kg-1·d-1; low-dose 1 g·kg-1·d-1) and for 7 days with 5-fluorouracil (5-FU, 25 g·kg-1·d-1) by gavage and intraperitoneal injection, respectively. Tumor volume and weight decreased significantly in both groups of nude mice treated with LFBE. In addition, the cell apoptosis rate of the LFBE group was significantly higher than that of the control group and 5-FU groups as measured by the TUNEL assay. Moreover, the real-time fluorescent quantitative PCR and Western blot methods further confirmed these apoptosis-enhancing and growth-inhibiting effects. The involvement of LFBE in inducing apoptosis was confirmed by the expression of Bax, Bcl-2, caspase-3, and cyclinD1. The results showed that LFBE could induce subcutaneous transplantation tumor apoptosis in nude mice and could be used as a natural nutrient supplement or chemopreventive agent in the treatment of human colon cancer. Copyright © 2017 The Editorial Board of Biomedical and Environmental Sciences. Published by China CDC. All rights reserved.

Transient postnatal fluoxetine leads to decreased brain arachidonic acid metabolism and cytochrome P450 4A in adult mice.

PubMed

Ramadan, Epolia; Blanchard, Helene; Cheon, Yewon; Fox, Meredith A; Chang, Lisa; Chen, Mei; Ma, Kaizong; Rapoport, Stanley I; Basselin, Mireille

2014-05-01

Fetal and perinatal exposure to selective serotonin (5-HT) reuptake inhibitors (SSRIs) has been reported to alter childhood behavior, while transient early exposure in rodents is reported to alter their behavior and decrease brain extracellular 5-HT in adulthood. Since 5-HT2A/2C receptor-mediated neurotransmission can involve G-protein coupled activation of cytosolic phospholipase A2 (cPLA2), releasing arachidonic acid (ARA) from synaptic membrane phospholipid, we hypothesized that transient postnatal exposure to fluoxetine would alter brain ARA metabolism in adult mice. Brain ARA incorporation coefficients k* and rates Jin were quantitatively imaged following intravenous [1-(14)C]ARA infusion of unanesthetized adult mice that had been injected daily with fluoxetine (10mg/kg i.p.) or saline during postnatal days P4-P21. Expression of brain ARA metabolic enzymes and other relevant markers also was measured. On neuroimaging, k* and Jin was decreased widely in early fluoxetine- compared to saline-treated adult mice. Of the enzymes measured, cPLA2 activity was unchanged, while Ca(2+)-independent iPLA2 activity was increased. There was a significant 74% reduced protein level of cytochrome P450 (CYP) 4A, which can convert ARA to 20-HETE. Reduced brain ARA metabolism in adult mice transiently exposed to postnatal fluoxetine, and a 74% reduction in CYP4A protein, suggest long-term effects independent of drug presence in brain ARA metabolism, and in CYP4A metabolites. These changes might contribute to reported altered behavior following early SSRI in rodents. Published by Elsevier Ltd.

Thermal and single frequency counter-current ultrasound pretreatments of sodium caseinate: enzymolysis kinetics and thermodynamics, amino acids composition, molecular weight distribution and antioxidant peptides.

PubMed

Abdualrahman, Mohammed Adam Y; Ma, Haile; Zhou, Cunshan; Yagoub, Abu ElGasim A; Hu, Jiali; Yang, Xue

2016-12-01

Due to the disadvantages of traditional enzymolysis, pretreatments are crucial to enhance protein enzymolysis. Enzymolysis kinetics and thermodynamics, amino acids composition, molecular weight distribution, fluorescence spectroscopy and antioxidant activity of thermal (HT) and single frequency counter-current ultrasound (SCFU) pretreated sodium caseinate (NaCas) were studied. Enzymolysis of untreated NaCas (control) improved significantly (P < 0.05) by SFCU and followed by HT. Values of the Michaelis-Menten constant (K M ) of SFCU and HT were 0.0212 and 0.0250, respectively. HT and SFCU increased (P < 0.05) the reaction rate constant (k) by 38.64 and 90.91%, respectively at 298 K. k values decreased with increasing temperature. The initial activation energy (46.39 kJ mol -1 ) reduced (P < 0.05) by HT (39.66 kJ mol -1 ) and further by SFCU (33.42 kJ mol -1 ). SFCU-pretreated NaCas hydrolysates had the highest contents of hydrophobic, aromatic, positively and negatively charged amino acids. Medium-sized peptides (5000-1000 Da) are higher in SFCU (78.11%) than HT and the control. SFCU induced molecular unfolding of NaCas proteins. Accordingly, SFCU-pretreated NaCas hydrolysate exhibited the highest scavenging activity on DPPH and hydroxyl radicals, reducing power, and iron chelating ability. SFCU pretreatment would be a useful tool for production of bioactive peptides from NaCas hydrolysate. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

[Study on effect of jinshui liujun jian oral liquid on serum superoxide dismutase activity and malonyldialdehyde content in mice with chronic bronchitis].

PubMed

Zhao, C Y; Shen, Y S; Meng, H

2001-11-01

To study the effect of Jinshui Liujun Jian Oral Liquid (JLJOL) on serum superoxide dismutase (SOD) activity and malonyldialdehyde (MDA) content in mice with chronic bronchitis. JLJOL was given to the chronic bronchitis mice model (induced by smoking) through gastrogavage, and then SOD activity and MDA content were tested. SOD activity in model mice after JLJOL treatment was 0.67 +/- 0.15 NU/L, which was significantly higher than that in the untreated model (0.39 +/- 0.13 NU/L, P < 0.01). But the MDA content in treated mice was significantly lower than that in untreated one (9.26 +/- 2.90 nmol/L vs 16.07 +/- 5.62 nmol/L, P < 0.01). JLJOL could scavenge the injury of free radical on organism.

Follicular lymphomas and their transformation: Past and current research.

PubMed

Mendez, Miriam; Torrente, Maria; Provencio, Mariano

2017-06-01

Follicular lymphoma (FL) is the second most common type of non-Hodgkin lymphoma (NHL). Histological transformation (HT) refers to the evolution of a clinically indolent NHL to a clinically aggressive one, defined as those lymphomas in which survival is limited to a few months when untreated. Areas covered: HT is associated with rapid progression of lymphadenopathy, infiltration of extranodal sites, development of systemic symptoms, and elevated serum level of lactate dehydrogenase (LDH). It is frequently related to a poor prognosis, and the median survival after transformation is less than 2 years. Transformation to diffuse large B cell lymphoma (DLBCL) in patients with FL occurs at an annual rate of approximately 3% for the first 15 years, after which the risk of HT falls for reasons that remain unclear. Expert commentary: Although it has long been assumed that transformation reflects the emergence of an aggressive subclone of cells from the primary FL, recent studies suggest that FL transformation might also arise by divergent evolution from a more immature common progenitor cell. Studies on genomic changes and DNA sequencing have shed some light onto the process of transformation. Nowadays, we know that HT is a complex process where several molecular pathways are involved.

Autocatalytic caspase-3 driven by human telomerase reverse transcriptase promoter suppresses human ovarian carcinoma growth in vitro and in mice.

PubMed

Song, Yue; Xia, Zhijun; Shen, Keng; Zhai, Xingyue

2013-05-01

To construct recombinant adenoviruses AdHT-rev-casp3 and Ad-rev-casp3, which express autocatalysis caspase-3 driven by human telomerase reverse transcriptase promoter and cytomegalovirus promoter, respectively; and to investigate their antitumor effects on ovarian cancer in vitro and in vivo. Cell viabilities were determined using the cell counting kit 8 and flow cytometry. Reverse transcriptase polymerase chain reaction and immunoblotting assays were used to detect cellular apoptotic activities after treatments. Tumor growth and survival of mice bearing AO cells were studied. AdHT-rev-casp3 significantly suppressed the survival of AO cells in a dose-dependent modality with a viability rate of 60.45% ± 7.8% at an multiplicity of infection (MOI) of 70 and 42.18 ± 5.3% at an MOI of 100, which was somewhat lower than that of the AO cells treated with Ad-rev-casp3 (32.28% ± 5.3% and 21.84% ± 3.4%, respectively). In contrast, AdHT-rev-casp3 induced little human umbilical vein epithelial cell (HUVEC) death with a viability rate of 98.52% ± 6.9% at an MOI of 70, whereas Ad-rev-casp3 induced significant cell death in HUVEC with a viability rate of 27.14% ± 5.4%. Additionally, AdHT-rev-casp3 (MOI = 70) caused significant apoptosis in AO cells with an apoptotic rate of 25.97%, whereas it caused undetectable apoptosis in HUVECs with the rate of only 1.75%. Ad-rev-casp3 (MOI = 70) caused strong apoptosis in both AO and HUVECs, with the rate of 35.82% and 38.12%, respectively. AdHT-rev-casp3 caused markedly higher levels of active caspase-3, causing no detectable active caspase-3 expression in HUVECs. The tumor growth suppression rate of AdHT-rev-casp3 was 54.94%, significantly higher than that of phosphate-buffered saline at the end point of the study. AdHT-rev-casp3 significantly improved the survival of mice receiving intraperitoneal inoculation of AO cells with little liver damage, with the mean survival of 177 ± 12 days. AdHT-rev-casp3 causes effective apoptosis with significant tumor selectivity, suppresses tumor growth, and improves the mouse survival with little liver toxicity. It can be a potent therapeutic agent for the tumor-targeting treatment of ovarian cancer.

Age and cellular context influence rectal prolapse formation in mice with caecal wall colorectal cancer xenografts.

PubMed

Tommelein, Joke; Gremonprez, Félix; Verset, Laurine; De Vlieghere, Elly; Wagemans, Glenn; Gespach, Christian; Boterberg, Tom; Demetter, Pieter; Ceelen, Wim; Bracke, Marc; De Wever, Olivier

2016-11-15

In patients with rectal prolapse is the prevalence of colorectal cancer increased, suggesting that a colorectal tumor may induce rectal prolapse. Establishment of tumor xenografts in immunodeficient mice after orthotopic inoculations of human colorectal cancer cells into the caecal wall is a widely used approach for the study of human colorectal cancer progression and preclinical evaluation of therapeutics. Remarkably, 70% of young mice carrying a COLO320DM caecal tumor showed symptoms of intussusception of the large bowel associated with intestinal lumen obstruction and rectal prolapse. The quantity of the COLO320DM bioluminescent signal of the first three weeks post-inoculation predicts prolapse in young mice. Rectal prolapse was not observed in adult mice carrying a COLO320DM caecal tumor or young mice carrying a HT29 caecal tumor. In contrast to HT29 tumors, which showed local invasion and metastasis, COLO320DM tumors demonstrated a non-invasive tumor with pushing borders without presence of metastasis. In conclusion, rectal prolapse can be linked to a non-invasive, space-occupying COLO320DM tumor in the gastrointestinal tract of young immunodeficient mice. These data reveal a model that can clarify the association of patients showing rectal prolapse with colorectal cancer.

Test-retest paradigm of the forced swimming test in female mice is not valid for predicting antidepressant-like activity: participation of acetylcholine and sigma-1 receptors.

PubMed

Su, Jing; Hato-Yamada, Noriko; Araki, Hiroaki; Yoshimura, Hiroyuki

2013-01-01

The forced swimming test (FST) in mice is widely used to predict the antidepressant activity of a drug, but information describing the immobility of female mice is limited. We investigated whether a prior swimming experience affects the immobility duration in a second FST in female mice and whether the test-retest paradigm is a valid screening tool for antidepressants. Female ICR mice were exposed to the FST using two experimental paradigms: a single FST and a double FST in which mice had experienced FST once 24 h prior to the second trail. The initial FST experience reliably prolonged immobility duration in the second FST. The antidepressants imipramine and paroxetine significantly reduced immobility duration in the single FST, but not in the double FST. Scopolamine and the sigma-1 (σ1) antagonist NE-100 administered before the second trial significantly prevented the prolongation of immobility. Neither a 5-HT1A nor a 5-HT2A receptor agonist affected immobility duration. We suggest that the test-retest paradigm in female mice is not adequate for predicting antidepressant-like activity of a drug; the prolongation of immobility in the double FST is modulated through acetylcholine and σ1 receptors.

Hippocampal 5-HT Input Regulates Memory Formation and Schaffer Collateral Excitation.

PubMed

Teixeira, Catia M; Rosen, Zev B; Suri, Deepika; Sun, Qian; Hersh, Marc; Sargin, Derya; Dincheva, Iva; Morgan, Ashlea A; Spivack, Stephen; Krok, Anne C; Hirschfeld-Stoler, Tessa; Lambe, Evelyn K; Siegelbaum, Steven A; Ansorge, Mark S

2018-06-06

The efficacy and duration of memory storage is regulated by neuromodulatory transmitter actions. While the modulatory transmitter serotonin (5-HT) plays an important role in implicit forms of memory in the invertebrate Aplysia, its function in explicit memory mediated by the mammalian hippocampus is less clear. Specifically, the consequences elicited by the spatio-temporal gradient of endogenous 5-HT release are not known. Here we applied optogenetic techniques in mice to gain insight into this fundamental biological process. We find that activation of serotonergic terminals in the hippocampal CA1 region both potentiates excitatory transmission at CA3-to-CA1 synapses and enhances spatial memory. Conversely, optogenetic silencing of CA1 5-HT terminals inhibits spatial memory. We furthermore find that synaptic potentiation is mediated by 5-HT4 receptors and that systemic modulation of 5-HT4 receptor function can bidirectionally impact memory formation. Collectively, these data reveal powerful modulatory influence of serotonergic synaptic input on hippocampal function and memory formation. Copyright © 2018 Elsevier Inc. All rights reserved.

Examining Autism Spectrum Disorders by Biomarkers: Example From the Oxytocin and Serotonin Systems

PubMed Central

Hammock, Elizabeth; Veenstra-VanderWeele, Jeremy; Yan, Zhongyu; Kerr, Travis M.; Morris, Marianna; Anderson, George; Carter, C. Sue; Cook, Edwin H.; Jacob, Suma

2013-01-01

Objective Autism Spectrum Disorder (ASD) is a heritable but highly heterogeneous neuropsychiatric syndrome, which poses challenges for research relying solely on behavioral symptoms or diagnosis. Examining biomarkers may give us ways to identify individuals who demonstrate specific developmental trajectories and etiological factors related to ASD. Plasma oxytocin (OT) and whole blood serotonin (5-HT) levels are consistently altered in some individuals with ASD. Reciprocal relationships have been described between brain oxytocin and serotonin systems during development. We therefore investigated the relationship between these peripheral biomarkers as well as their relationships with age. Method In our first study, we analyzed correlations between these two biomarkers in 31 children and adolescents who were diagnosed with autism and were not on medications. In our second study, we explored whether whole blood 5-HT levels are altered in mice lacking the oxytocin receptor gene, Oxtr. Results In humans, OT and 5-HT were negatively correlated with each other (p<0.05) and this relationship was most prominent in children under 11 years old. Paralleling human findings, mice lacking Oxtr showed increased whole blood 5-HT levels (p=0.05), with this effect driven exclusively by mice younger than 4 months of age (p< 0.01). Conclusions Identifying relationships between identified ASD biomarkers may be a useful approach to connect otherwise disparate findings that span multiple systems in this heterogeneous disorder. Using neurochemical biomarkers to do parallel studies in animal and human populations within a developmental context is a plausible approach to probe the root causes of ASD and identify potential interventions. PMID:22721594

Mirtazapine has a therapeutic potency in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced mice model of Parkinson’s disease

PubMed Central

2014-01-01

Background Mirtazapine, a noradrenergic and specific serotonergic antidepressant (NaSSA), shows multiple pharmacological actions such as inhibiting presynaptic α2 noradrenaline receptor (NAR) and selectively activating 5-hydroxytriptamine (5-HT) 1A receptor (5-HT1AR). Mirtazapine was also reported to increase dopamine release in the cortical neurons with 5-HT dependent manner. To examine whether mirtazapine has a therapeutic potency in Parkinson’s disease (PD), we examined this compound in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated mice model of PD. Results Male C57BL/6 mice were subjected to MPTP treatment to establish a PD model. Mirtazapine was administered once a day for 3 days after MPTP treatment. MPTP-induced motor dysfunction, assessed by beam-walking and rota-rod tests, was significantly improved by administration of mirtazapine. Biochemical examinations by high performance liquid chromatography and western blot analysis suggested mirtazapine facilitated utilization of dopamine by increasing turnover and protein expression of transporters, without affecting on neurodegenerative process by MPTP. These therapeutic effects of mirtazapine were reduced by administration of WAY100635, an inhibitor for 5HT1AR, or of clonidine, a selective agonist for α2-NAR, or of prazosin, an inhibitor for α1-NAR, respectively. Conclusion Our results showed mirtazapine had a therapeutic potency against PD in a mouse model. Because PD patients sometimes show depression together, it will be a useful drug for a future PD treatment. PMID:24965042

Elevated Thyroid Peroxidase Antibody Increases Risk of Post-partum Depression by Decreasing Prefrontal Cortex BDNF and 5-HT Levels in Mice.

PubMed

Zhou, Yingying; Wang, Xinyi; Zhao, Yuhang; Liu, Aihua; Zhao, Tong; Zhang, Yuanyuan; Shan, Zhongyan; Teng, Weiping

2016-01-01

Post-partum depression (PPD) is a common mental disease in the perinatal period that profoundly affects mothers and their offspring. Some clinical studies have found that PPD is related to thyroid peroxidase antibodies (TPOAbs); however, the mechanism underlying this relationship is unclear. Female C57BL/6 mice immunized with adenovirus encoding the cDNA of the full-length mTPO (mTPO-Ad) were used to establish the isolated TPOAb-positive mouse model in the present study. Maternal depressive-like behaviors were assessed using the forced swimming test (FST), sucrose preference test (SPT), and tail suspension test (TST) post-partum. The serum TPOAb titer was measured by enzyme-linked immunosorbent assay (ELISA) before pregnancy and post-partum. Furthermore, in the prefrontal cortex, the mRNA and protein expression levels of brain-derived neurotrophic factor (BDNF) were measured, serotonin (5-HT) levels were measured by ultra-high-performance liquid chromatography-tandem mass-spectrometry (UHPLC-MS/MS), and total thyroxine (TT4) levels were determined by ELISA. Compared with the controls, the mice immunized with mTPO-Ad displayed depressive behaviors, with a significantly lower sucrose preference (SP) at the 12-h time point and a longer immobility time in the FST and TST, which were accompanied by a lower expression of BDNF and 5-HT but no change in the TT4 concentration in the prefrontal cortex. Together, these findings suggest that elevated TPOAb may increase the risk of subsequent PPD and decrease the concentration of BDNF and 5-HT in the prefrontal cortex.

Acetaminophen Differentially Enhances Social Behavior and Cortical Cannabinoid Levels in Inbred Mice

PubMed Central

Gould, Georgianna G.; Seillier, Alexandre; Weiss, Gabriela; Giuffrida, Andrea; Burke, Teresa F.; Hensler, Julie G.; Rock, Crystal; Tristan, Amanda; McMahon, Lance R.; Salazar, Alexander; O’Connor, Jason C.; Satsangi, Neera; Satsangi, Rajiv K.; Gu, Ting-Ting; Treat, Keenan; Smolik, Corey; Schultz, Stephen T.

2012-01-01

Supratherapeutic doses of the analgesic acetaminophen (paracetomol) are reported to promote social behavior in Swiss mice. However, we hypothesized that it might not promote sociability in other strains due to cannabinoid CB1 receptor-mediated inhibition of serotonin (5-HT) transmission in the frontal cortex. We examined the effects of acetaminophen on social and repetitive behaviors in comparison to a cannabinoid agonist, WIN 55,212-2, in two strains of socially-deficient mice, BTBR and 129S1/SvImJ (129S). Acetaminophen (100 mg/kg) enhanced social interactions in BTBR, and social novelty preference and marble burying in 129S at serum levels ≥70 ng/ml. Following acetaminophen injection or sociability testing, anandamide (AEA) increased in BTBR frontal cortex, while behavior testing increased 2-arachidonyl glycerol (2-AG) levels in 129S frontal cortex. In contrast, WIN 55,212-2 (0.1 mg/kg) did not enhance sociability. Further, we expected CB1-deficient (+/−) mice to be less social than wild-type, but instead found similar sociability. Given strain differences in endocannabinoid response to acetaminophen, we compared cortical CB1 and 5-HT1A receptor density and function relative to sociable C57BL/6 mice. CB1 receptor saturation binding (Bmax= 958±117 fmol/mg protein), and affinity for [3H]CP55,940 (KD= 3±0.8 nM) was similar in frontal cortex among strains. CP55,940-stimulated [35S]GTPγS binding in cingulate cortex was 136±12, 156±22, and 75±9% above basal in BTBR, 129S and C57BL/6 mice. The acetaminophen metabolite para-aminophenol (1μM) failed to stimulate [35S]GTPγS binding. Hence, it appears that other indirect actions of acetaminophen, including 5-HT receptor agonism, may underlie its sociability promoting properties outweighing any CB1 mediated suppression by locally-elevated endocannabinoids in these mice. PMID:22542870

Coconut water vinegar ameliorates recovery of acetaminophen induced liver damage in mice.

PubMed

Mohamad, Nurul Elyani; Yeap, Swee Keong; Beh, Boon-Kee; Ky, Huynh; Lim, Kian Lam; Ho, Wan Yong; Sharifuddin, Shaiful Adzni; Long, Kamariah; Alitheen, Noorjahan Banu

2018-06-25

Coconut water has been commonly consumed as a beverage for its multiple health benefits while vinegar has been used as common seasoning and a traditional Chinese medicine. The present study investigates the potential of coconut water vinegar in promoting recovery on acetaminophen induced liver damage. Mice were injected with 250 mg/kg body weight acetaminophen for 7 days and were treated with distilled water (untreated), Silybin (positive control) and coconut water vinegar (0.08 mL/kg and 2 mL/kg body weight). Level of oxidation stress and inflammation among treated and untreated mice were compared. Untreated mice oral administrated with acetaminophen were observed with elevation of serum liver profiles, liver histological changes, high level of cytochrome P450 2E1, reduced level of liver antioxidant and increased level of inflammatory related markers indicating liver damage. On the other hand, acetaminophen challenged mice treated with 14 days of coconut water vinegar were recorded with reduction of serum liver profiles, improved liver histology, restored liver antioxidant, reduction of liver inflammation and decreased level of liver cytochrome P450 2E1 in dosage dependent level. Coconut water vinegar has helped to attenuate acetaminophen-induced liver damage by restoring antioxidant activity and suppression of inflammation.

Microglial activation, increased TNF and SERT expression in the prefrontal cortex define stress-altered behaviour in mice susceptible to anhedonia.

PubMed

Couch, Yvonne; Anthony, Daniel C; Dolgov, Oleg; Revischin, Alexander; Festoff, Barry; Santos, Ana Isabel; Steinbusch, Harry W; Strekalova, Tatyana

2013-03-01

A chronic stress paradigm comprising exposure to predation, tail suspension and restraint induces a depressive syndrome in C57BL/6J mice that occurs in some, but not all, animals. Here, we sought to extend our behavioural studies to investigate how susceptibility (sucrose preference<65%) or resilience (sucrose preference>65%) to stress-induced anhedonia affects the 5HT system and the expression of inflammation-related genes. All chronically stressed animals, displayed increased level of anxiety, but susceptible mice exhibited an increased propensity to float in the forced swim test and demonstrate hyperactivity under stressful lighting conditions. These changes were not present in resilient or acutely stressed animals. Compared to resilient animals, susceptible mice showed elevated expression of tumour necrosis factor alpha (TNF) and the 5-HT transporter (SERT) in the pre-frontal area. Enhanced expression of 5HT(2A) and COX-1 in the pre-frontal area was observed in all stressed animals. In turn, indoleamine-2,3-dioxygenase (IDO) was significantly unregulated in the raphe of susceptible animals. At the cellular level, increased numbers of Iba-1-positive microglial cells were also present in the prefrontal area of susceptible animals compared to resilient animals. Consequently, the susceptible animals display a unique molecular profile when compared to resilient, but anxious, animals. Unexpectedly, this altered profile provides a rationale for exploring anti-inflammatory, and possibly, TNF-targeted therapy for major depression. Copyright © 2013 Elsevier Inc. All rights reserved.

Combined Memantine and Donepezil Treatment Improves Behavioral and Psychological Symptoms of Dementia-Like Behaviors in Olfactory Bulbectomized Mice.

PubMed

Yabuki, Yasushi; Matsuo, Kazuya; Hirano, Koga; Shinoda, Yasuharu; Moriguchi, Shigeki; Fukunaga, Kohji

2017-01-01

Memantine, an uncompetitive N-methyl-D-aspartate receptor antagonist, and the cholinesterase inhibitor, donepezil, are approved in most countries for treating moderate-to-severe Alzheimer's disease (AD). These drugs have different molecular targets; thus, it is expected that the effects of combined treatment would be synergistic. Some reports do show memantine/donepezil synergy in ameliorating cognition in AD model animals, but their combined effects on behavioral and psychological symptoms of dementia (BPSD)-like behaviors have not been addressed. Here, we investigate combined memantine/donepezil effects on cognitive impairment and BPSD-like behaviors in olfactory bulbectomized (OBX) mice. Interestingly, combined administration synergistically improved both depressive-like behaviors and impaired social interaction in OBX mice, whereas only weak synergistic effects on cognitive performance were seen. To address mechanisms underlying these effects, we used in vivo microdialysis study and observed impaired nicotine-induced serotonin (5-HT) release in OBX mouse hippocampus. Combined memantine/donepezil administration, but not single administration of either, significantly antagonized the decrease in nicotine-induced 5-HT release seen in OBX mouse hippocampus. Furthermore, decreased autophosphorylation of calcium/calmodulin dependent protein kinase II (CaMKII) was rescued in hippocampal CA1 and dentate gyrus of OBX mice by combined memantine/donepezil administration. These results suggest that improvement of BPSD-like behaviors by the co-administration of both drugs is in part mediated by enhanced 5-HT release and CaMKII activity in OBX mouse hippocampus. © 2016 S. Karger AG, Basel.

Rhubarb tannins extract inhibits the expression of aquaporins 2 and 3 in magnesium sulphate-induced diarrhoea model.

PubMed

Liu, Chunfang; Zheng, Yanfang; Xu, Wen; Wang, Hui; Lin, Na

2014-01-01

Tannins, a group of major active components of Chinese rhubarb and widely distributed in nature, have a significant antidiarrhoeal activity. Aquaporins (AQPs) 2 and 3 play important roles in regulating water transfer during diarrhoea. The present study aims to determine the effect of the total tannins extract of rhubarb on aquaporins (AQPs) 2 and 3 in diarrhoea mice and HT-29 cells both induced by magnesium sulphate (MgSO4). Our results showed that rhubarb tannins extract (RTE) significantly decreased the faecal water content in colon and evaluation index of defecation of diarrhoea mice. Interestingly, RTE could markedly reduce the mRNA and protein expression levels of AQPs 2 and 3 in apical and lateral mucosal epithelial cells in the colons of diarrhoea mice and HT-29 cells both induced by MgSO4 in a dose-dependent manner. Furthermore, RTE suppressed the production of cyclic monophosphate- (cAMP-) dependent protein kinase A catalytic subunits α (PKA C-α) and phosphorylated cAMP response element-binding protein (p-CREB, Ser133) in MgSO4-induced HT-29 cells. Our data showed for the first time that RTE inhibit AQPs 2 and 3 expression in vivo and in vitro via downregulating PKA/p-CREB signal pathway, which accounts for the antidiarrhoeal effect of RTE.

5-HT1A and 5-HT7 receptor crosstalk in the regulation of emotional memory: implications for effects of selective serotonin reuptake inhibitors.

PubMed

Eriksson, Therese M; Holst, Sarah; Stan, Tiberiu L; Hager, Torben; Sjögren, Benita; Ogren, Sven Öve; Svenningsson, Per; Stiedl, Oliver

2012-11-01

This study utilized pharmacological manipulations to analyze the role of direct and indirect activation of 5-HT(7) receptors (5-HT(7)Rs) in passive avoidance learning by assessing emotional memory in male C57BL/6J mice. Additionally, 5-HT(7)R binding affinity and 5-HT(7)R-mediated protein phosphorylation of downstream signaling targets were determined. Elevation of 5-HT by the selective serotonin reuptake inhibitor (SSRI) fluoxetine had no effect by itself, but facilitated emotional memory performance when combined with the 5-HT(1A)R antagonist NAD-299. This facilitation was blocked by the selective 5-HT(7)R antagonist SB269970, revealing excitatory effects of the SSRI via 5-HT(7)Rs. The enhanced memory retention by NAD-299 was blocked by SB269970, indicating that reduced activation of 5-HT(1A)Rs results in enhanced 5-HT stimulation of 5-HT(7)Rs. The putative 5-HT(7)R agonists LP-44 when administered systemically and AS19 when administered both systemically and into the dorsal hippocampus failed to facilitate memory. This finding is consistent with the low efficacy of LP-44 and AS19 to stimulate protein phosphorylation of 5-HT(7)R-activated signaling cascades. In contrast, increasing doses of the dual 5-HT(1A)R/5-HT(7)R agonist 8-OH-DPAT impaired memory, while co-administration with NAD-299 facilitated of emotional memory in a dose-dependent manner. This facilitation was blocked by SB269970 indicating 5-HT(7)R activation by 8-OH-DPAT. Dorsohippocampal infusion of 8-OH-DPAT impaired passive avoidance retention through hippocampal 5-HT(1A)R activation, while 5-HT(7)Rs appear to facilitate memory processes in a broader cortico-limbic network and not the hippocampus alone. Copyright © 2012 Elsevier Ltd. All rights reserved.

Effects of the brain-penetrant and selective 5-HT6 receptor antagonist SB-399885 in animal models of anxiety and depression.

PubMed

Wesołowska, Anna; Nikiforuk, Agnieszka

2007-04-01

The effects of a selective 5-HT(6) receptor antagonist, SB-399885 (N-[3,5-dichloro-2-(methoxy)phenyl]-4-(methoxy)-3-(1-piperazinyl)benzenesulfonamide), were evaluated in behavioural tests sensitive to clinically effective anxiolytic- and antidepressant-compounds using diazepam and imipramine as reference drugs. In the Vogel conflict drinking test in rats, SB-399885 (1-3mg/kg i.p.) caused an anxiolytic-like activity comparable to that of diazepam (2.5-5mg/kg i.p.). An anxiolytic-like effect was also seen in the elevated plus-maze test in rats, where SB-399885 (0.3-3mg/kg i.p.) was slightly weaker than diazepam (2.5-5mg/kg i.p.). In the four-plate test in mice, SB-399885 (3-20mg/kg i.p.) showed an anxiolytic-like effect which was weaker than that produced by diazepam (2.5-5mg/kg i.p.). In the forced swim test in rats, SB-399885 (10mg/kg i.p.) significantly shortened the immobility time and the effect was stronger than that of imipramine (30mg/kg i.p.). In the forced swim test in mice, SB-399885 (20-30mg/kg i.p.) had an anti-immobility action, comparable to imipramine (30mg/kg i.p.) and also in the tail suspension test in mice, SB-399885 (10-30mg/kg i.p.) had an antidepressant-like effect, though was weaker than imipramine (10-20mg/kg i.p.). The tested 5-HT(6) antagonist (3-20mg/kg i.p.) shortened the walking time of rats in the open field test and, at a dose of 30mg/kg i.p. reduced the locomotor activity of mice. SB-399885 (in doses up to 30mg/kg i.p.) did not affect motor coordination in mice and rats tested in the rota-rod test. Such data indicate that the selective 5-HT(6) receptor antagonist SB-399885had specific effects, indicative of this compound's anxiolytic and antidepressant potential.

Enhanced scratching evoked by PAR-2 agonist and 5-HT but not histamine in a mouse model of chronic dry skin itch.

PubMed

Akiyama, T; Carstens, M Iodi; Carstens, E

2010-11-01

Chronic itch is a symptom of many skin conditions and systemic disease, and it has been hypothesized that the chronic itch may result from sensitization of itch-signaling pathways. We induced experimental chronic dry skin on the rostral back of mice, and observed a significant increase in spontaneous hindlimb scratches directed to the dry skin. Spontaneous scratching was significantly attenuated by a PAR-2 antibody and 5-HT2A receptor antagonist, indicating activation of these receptors by endogenous mediators released under dry skin conditions. We also observed a significant increase in the number of scratch bouts evoked by acute intradermal injections of a protease-activated receptor (PAR)-2 agonist and serotonin (5-HT), but not histamine. We additionally investigated if pruritogen-evoked activity of dorsal root ganglion (DRG) neurons is enhanced in this model. DRG cells from dry skin mice exhibited significantly larger responses to the PAR-2 agonist and 5-HT, but not histamine. Spontaneous scratching may reflect ongoing itch, and enhanced pruritogen-evoked scratching may represent hyperknesis (enhanced itch), both potentially due to sensitization of itch-signaling neurons. The correspondence between enhanced behavioral scratching and DRG cell responses suggest that peripheral pruriceptors that respond to proteases and 5-HT, but not histamine, may be sensitized in dry skin itch. Copyright © 2010 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

Evaluation of (188)Re-labeled NGR-VEGI protein for radioimaging and radiotherapy in mice bearing human fibrosarcoma HT-1080 xenografts.

PubMed

Ma, Wenhui; Shao, Yahui; Yang, Weidong; Li, Guiyu; Zhang, Yingqi; Zhang, Mingru; Zuo, Changjing; Chen, Kai; Wang, Jing

2016-07-01

Vascular endothelial growth inhibitor (VEGI) is an anti-angiogenic protein, which includes three isoforms: VEGI-174, VEGI-192, and VEGI-251. The NGR (asparagine-glycine-arginine)-containing peptides can specifically bind to CD13 (Aminopeptidase N) receptor which is overexpressed in angiogenic blood vessels and tumor cells. In this study, a novel NGR-VEGI fusion protein was prepared and labeled with (188)Re for radioimaging and radiotherapy in mice bearing human fibrosarcoma HT-1080 xenografts. Single photon emission computerized tomography (SPECT) imaging results revealed that (188)Re-NGR-VEGI exhibits good tumor-to-background contrast in CD13-positive HT-1080 tumor xenografts. The CD13 specificity of (188)Re-NGR-VEGI was further verified by significant reduction of tumor uptake in HT-1080 tumor xenografts with co-injection of the non-radiolabeled NGR-VEGI protein. The biodistribution results demonstrated good tumor-to-muscle ratio (4.98 ± 0.25) of (188)Re-NGR-VEGI at 24 h, which is consistent with the results from SPECT imaging. For radiotherapy, 18.5 MBq of (188)Re-NGR-VEGI showed excellent tumor inhibition effect in HT-1080 tumor xenografts with no observable toxicity, which was confirmed by the tumor size change and hematoxylin and eosin (H&E) staining of major mouse organs. In conclusion, these data demonstrated that (188)Re-NGR-VEGI has the potential as a theranostic agent for CD13-targeted tumor imaging and therapy.

Receptor-targeted therapy of human experimental urinary bladder cancers with cytotoxic LH-RH analog AN-152 [AEZS- 108].

PubMed

Szepeshazi, Karoly; Schally, Andrew V; Keller, Gunhild; Block, Norman L; Benten, Daniel; Halmos, Gabor; Szalontay, Luca; Vidaurre, Irving; Jaszberenyi, Miklos; Rick, Ferenc G

2012-07-01

Many bladder cancers progress to invasion with poor prognosis; new therapeutic methods are needed. We developed a cytotoxic LH-RH analog, AN-152 (AEZS-108) containing doxorubicin (DOX), for targeted therapy of cancers expressing LHRH receptors. We investigated the expression of LH-RH receptors in clinical bladder cancers and in HT-1376, J82, RT-4 and HT-1197 human bladder cancer lines. The effect of analog, AN-152, on growth of these tumor lines xenografted into nude mice was analyzed. Using molecular and functional assays, we also evaluated the differences between the effects of AN-152, and DOX alone. We demonstrated the expression of LH-RH receptors on 18 clinical bladder cancers by immunohistochemistry and on four human urinary bladder cancer lines HT-1376, J82, RT-4 and HT-1197 by Western blotting and binding assays. AN-152 powerfully inhibited growth of these bladder cancers in nude mice. AN-152 exerted greater effects than DOX and was less toxic. DOX activated strong multidrug resistance mechanisms in RT-4 and HT-1197 cancers, while AN-152 had no or less such effect. PCR assays and in vitro studies revealed differences in the action of AN-152 and DOX on the expression of genes involved in apoptosis. These results suggest that targeted cytotoxic LH-RH analog, AN-152 (AEZS- 108), should be examined for treatment of patients with LH-RH receptor positive invasive bladder cancers.

Effects of psilocybin on hippocampal neurogenesis and extinction of trace fear conditioning.

PubMed

Catlow, Briony J; Song, Shijie; Paredes, Daniel A; Kirstein, Cheryl L; Sanchez-Ramos, Juan

2013-08-01

Drugs that modulate serotonin (5-HT) synaptic concentrations impact neurogenesis and hippocampal (HPC)-dependent learning. The primary objective is to determine the extent to which psilocybin (PSOP) modulates neurogenesis and thereby affects acquisition and extinction of HPC-dependent trace fear conditioning. PSOP, the 5-HT2A agonist 25I-NBMeO and the 5-HT2A/C antagonist ketanserin were administered via an acute intraperitoneal injection to mice. Trace fear conditioning was measured as the amount of time spent immobile in the presence of the conditioned stimulus (CS, auditory tone), trace (silent interval) and post-trace interval over 10 trials. Extinction was determined by the number of trials required to resume mobility during CS, trace and post-trace when the shock was not delivered. Neurogenesis was determined by unbiased counts of cells in the dentate gyrus of the HPC birth-dated with BrdU co-expressing a neuronal marker. Mice treated with a range of doses of PSOP acquired a robust conditioned fear response. Mice injected with low doses of PSOP extinguished cued fear conditioning significantly more rapidly than high-dose PSOP or saline-treated mice. Injection of PSOP, 25I-NBMeO or ketanserin resulted in significant dose-dependent decreases in number of newborn neurons in hippocampus. At the low doses of PSOP that enhanced extinction, neurogenesis was not decreased, but rather tended toward an increase. Extinction of "fear conditioning" may be mediated by actions of the drugs at sites other than hippocampus such as the amygdala, which is known to mediate the perception of fear. Another caveat is that PSOP is not purely selective for 5-HT2A receptors. PSOP facilitates extinction of the classically conditioned fear response, and this, and similar agents, should be explored as potential treatments for post-traumatic stress disorder and related conditions.

Antipsychotic-like vs cataleptogenic actions in mice of novel antipsychotics having D2 antagonist and 5-HT1A agonist properties.

PubMed

Bardin, Laurent; Kleven, Mark S; Barret-Grévoz, Catherine; Depoortère, Ronan; Newman-Tancredi, Adrian

2006-09-01

A new generation of proven or potential antipsychotics, including aripiprazole, bifeprunox, SSR181507 and SLV313, exhibit agonist actions at serotonin 5-HT1A receptors, but little comparative data are available on their pharmacological profiles. Here, we compared in mice the in vivo antipsychotic-like vs cataleptogenic activities of these compounds with those of drugs that exhibit little interaction at 5-HT1A receptors, such as haloperidol, olanzapine and risperidone. All the drugs dose-dependently reduced apomorphine-induced climbing or sniffing and, with the exception of ziprasidone, produced complete suppression of these responses. In the bar catalepsy test, when administered alone, haloperidol, olanzapine and risperidone produced marked catalepsy, whereas, at doses up to 40 mg/kg, aripiprazole, SLV313, SSR181507, and sarizotan produced little or no catalepsy. The latter compounds, therefore, displayed a large separation between doses with 'antipsychotic-like' and those with cataleptogenic actions. When 5-HT1A receptors were blocked by pretreatment with WAY100635 (2.5 mg/kg, s.c.), cataleptogenic properties of SSR181507 and sarizotan were unmasked, and the catalepsy induced by bifeprunox was enhanced. In the case of aripiprazole and SLV313, although WAY100635 produced upward shifts in their dose-response, the magnitude of catalepsy appeared to reach an asymptotic plateau, suggesting that other mechanisms may be involved in their low cataleptogenic liability. The present data confirm that 5-HT1A receptor activation reduces or even completely prevents the cataleptogenic potential of novel antipsychotic agents. Further, they indicate that the balance of affinity and/or efficacy between D2 and 5-HT1A receptors profoundly influences their pharmacological activities, and will likely impact their therapeutic profiles.

Effect of Jobelyn® on intruder- and isolation-induced aggressive behavior in mice.

PubMed

Umukoro, Solomon; Omogbiya, Itivere Adrian; Eduviere, Taghogho Anthony

2013-01-01

Aggression is a violent behavior emitted against another organism that may lead to its harm or death and thus is of public health significance, which necessitates the search for agents with anti-aggressive property. This study investigated the effect of Jobelyn® (JB), a unique African polyherbal formulation, on intruder- and isolation-induced aggressive behaviors in mice. Male mice that showed aggression after being housed individually with female counterparts for 3 weeks or kept in isolation for 4 weeks were treated orally (p.o.) with JB (5, 10 or 50 mg/kg), haloperidol (HP) (1 mg/kg), fluoxetine (FL) (10 mg/kg), p-chlorophenylalanine (PCPA) (20 mg/kg), mianserin (MS) (50 mg/kg) or distilled water (10 mL/kg) 60 min before being tested for aggression. Interaction studies involving oral administration of PCPA (20 mg/kg), FL (10 mg/kg) or MS (50 mg/kg) to aggressive mice that had received JB (5 or 10 mg/kg, p.o.) 30 min earlier were assessed. The effect of JB (5, 10 or 50 mg/kg, p.o.) on defensive behaviors was also evaluated. JB (5, 10 or 50 mg/kg) decreased aggressive behaviors without impairing the defensive mechanisms of mice. PCPA (20 mg/kg), an inhibitor of 5-hydroxytryptamine (5-HT) biosynthesis, increased aggressive responses and reduced the anti-aggressive effect of JB. FL (10 mg/kg), a 5-HT reuptake inhibitor, significantly suppressed aggression but did not alter the effect of JB on aggression. MS (50 mg/kg), a 5-HT receptor antagonist, reduced aggression and enhanced the effect of JB on aggression. These findings suggest that JB has anti-aggressive activity, which may be related to the enhancement of serotonergic system.

Antitumor Activities and Apoptosis-regulated Mechanisms of Fermented Wheat Germ Extract in the Transplantation Tumor Model of Human HT-29 Cells in Nude Mice.

PubMed

Zhang, Jia Yan; Xiao, Xiang; Dong, Ying; Wu, Jing; Zhou, Xing Hua

2015-10-01

A subcutaneous transplantation tumor model of human HT-29 cells in nude mice was established to evaluate anticarcinogenic activities, and the apoptosis-regulated mechanism effect of aqueous extract of fermented wheat germ with Lactobacillus plantarum dy-1 (LFWGE). The HT-29 cells were transplanted via subcutaneous injection of 1×107 cells into the right flank of each nude mouse. Then, nude mice were treated for 30 d with LFWGE (high-dose 2 g/kg/d; low-dose 1 g/kg/d) and for 7 d with 5-fluorouracil (5-FU, 25 mg/kg/d) by gavage and intraperitoneal injection, respectively. An inhibition of tumor growth was observed. Tumor volume and weights decreased significantly in both groups of nude mice treated with LFWGE. In addition, the cell apoptosis rate of the LFWGE group (2 g/kg/d, 60.1%±4.4%; 1 g/kg/d, 58.6%±6.9%) was significantly higher than that of the control group (11.5%±1.6%) and 5-FU group (32.1%±3.5%) as measured by the TUNEL assay. Moreover, the real-time fluorescent quantitative PCR and Western blot method further confirmed these enhancing apoptosis and growth inhibition effects. The involvement of LFWGE in inducing apoptosis was confirmed by the expression of Bax, Bcl-2, Caspase-3, and CyclinD1. The results showed that LFWGE could induce subcutaneous transplantation tumor apoptosis in nude mice and could be as a natural nutrient supplements or chemopreventive agent in the treatment of human colon cancer. Copyright © 2015 The Editorial Board of Biomedical and Environmental Sciences. Published by China CDC. All rights reserved.

Efficacy of rabies immunoglobulins in an experimental post-exposure prophylaxis rodent model.

PubMed

Servat, Alexandre; Lutsch, Charles; Delore, Valentine; Lang, Jean; Veitch, Keith; Cliquet, Florence

2003-12-12

In a recently published Syrian hamster animal challenge study [Vaccine 19 (2001) 2273], a highly purified, heat-treated equine rabies immunoglobulin (pERIG HT, Favirab) did not elicit satisfactory protection. The efficacies of this batch, a second stage pERIG HT batch and reference RIG preparations (Imorab, Imogam Rage pasteurised, Berna antiserum) were compared in mice challenged with either Ariana canine field strain or CVS strain. Survival rates against Ariana challenge with the second pERIG HT batch were indistinguishable from those of other licensed preparations (83-90% survival), but the deficient batch did not provide satisfactory protection (53%). These data confirm the inadequate response to a first stage pERIG HT batch, but a current batch provides equivalent protection to that afforded by licensed HRIG and ERIG preparations.

Nanoscale-alumina induces oxidative stress and accelerates amyloid beta (Aβ) production in ICR female mice

NASA Astrophysics Data System (ADS)

Shah, Shahid Ali; Yoon, Gwang Ho; Ahmad, Ashfaq; Ullah, Faheem; Amin, Faiz Ul; Kim, Myeong Ok

2015-09-01

The adverse effects of nanoscale-alumina (Al2O3-NPs) have been previously demonstrated in both in vitro and in vivo studies, whereas little is known about their mechanism of neurotoxicity. It is the goal of this research to determine the toxic effects of nano-alumina on human neuroblastoma SH-SY5Y and mouse hippocampal HT22 cells in vitro and on ICR female mice in vivo. Nano-alumina displayed toxic effects on SH-SY5Y cell lines in three different concentrations also increased aluminium abundance and induced oxidative stress in HT22 cells. Nano-alumina peripherally administered to ICR female mice for three weeks increased brain aluminium and ROS production, disturbing brain energy homeostasis, and led to the impairment of hippocampus-dependent memory. Most importantly, these nano-particles induced Alzheimer disease (AD) neuropathology by enhancing the amyloidogenic pathway of Amyloid Beta (Aβ) production, aggregation and implied the progression of neurodegeneration in the cortex and hippocampus of these mice. In conclusion, these data demonstrate that nano-alumina is toxic to both cells and female mice and that prolonged exposure may heighten the chances of developing a neurodegenerative disease, such as AD.

[On the role of selective silencer Freud-1 in the regulation of the brain 5-HT(1A) receptor gene expression].

PubMed

Naumenko, V S; Osipova, D V; Tsybko, A S

2010-01-01

Selective 5-HT(1A) receptor silencer (Freud-1) is known to be one of the main factors for transcriptional regulation of brain serotonin 5-HT(1A) receptor. However, there is a lack of data on implication of Freud-1 in the mechanisms underlying genetically determined and experimentally altered 5-HT(1A) receptor system state in vivo. In the present study we have found a difference in the 5-HT(1A) gene expression in the midbrain of AKR and CBA inbred mouse strains. At the same time no distinction in Freud-1 expression was observed. We have revealed 90.3% of homology between mouse and rat 5-HT(1A) receptor DRE-element, whereas there was no difference in DRE-element sequence between AKR and CBA mice. This indicates the absence of differences in Freud-1 binding site in these mouse strains. In the model of 5-HT(1A) receptor desensitization produced by chronic 5-HT(1A) receptor agonist administration, a significant reduction of 5-HT(1A) receptor gene expression together with considerable increase of Freud-1 expression were found. These data allow us to conclude that the selective silencer of 5-HT(1A) receptor, Freud-1, is involved in the compensatory mechanisms that modulate the functional state of brain serotonin system, although it is not the only factor for 5-HT(1A) receptor transcriptional regulation.

In Vitro Evaluation of the Impact of the Probiotic E. coli Nissle 1917 on Campylobacter jejuni's Invasion and Intracellular Survival in Human Colonic Cells.

PubMed

Helmy, Yosra A; Kassem, Issmat I; Kumar, Anand; Rajashekara, Gireesh

2017-01-01

Campylobacter jejuni is a leading cause of bacterial food poisoning in humans. Due to the rise in antibiotic-resistant Campylobacter , there exists a need to develop antibiotic-independent interventions to control infections in humans. Here, we evaluated the impact of Escherichia coli Nissle 1917 (EcN), a probiotic strain, on C. jejuni's invasion and intracellular survival in polarized human colonic cells (HT-29). To further understand how EcN mediates its impact, the expression of 84 genes associated with tight junctions and cell adhesion was profiled in HT-29 cells after treatment with EcN and challenge with C. jejuni . The pre-treatment of polarized HT-29 cells with EcN for 4 h showed a significant effect on C. jejuni 's invasion (∼2 log reduction) of the colonic cells. Furthermore, no intracellular C. jejuni were recovered from EcN pre-treated HT-29 cells at 24 h post-infection. Other probiotic strains tested had no significant impact on C. jejuni invasion and intracellular survival. C. jejuni decreased the expression of genes associated with epithelial cells permeability and barrier function in untreated HT-29 cells. However, EcN positively affected the expression of genes that are involved in enhanced intestinal barrier function, decreased cell permeability, and increased tight junction integrity. The results suggest that EcN impedes C. jejuni invasion and subsequent intracellular survival by affecting HT-29 cells barrier function and tight junction integrity. We conclude that EcN might be a viable alternative for controlling C. jejuni infections.

The role of p38 in mitochondrial respiration in male and female mice.

PubMed

Ju, Xiaohua; Wen, Yi; Metzger, Daniel; Jung, Marianna

2013-06-07

p38 is a mitogen-activated protein kinase and mediates cell growth, cell differentiation, and synaptic plasticity. The aim of this study is to determine the extent to which p38 plays a role in maintaining mitochondrial respiration in male and female mice under a normal condition. To achieve this aim, we have generated transgenic mice that lack p38 in cerebellar Purkinje neurons by crossing Pcp2 (Purkinje cell protein 2)-Cre mice with p38(loxP/loxP) mice. Mitochondria from cerebellum were then isolated from the transgenic and wild-type mice to measure mitochondrial respiration using XF24 respirometer. The mRNA and protein expression of cytochrome c oxidase (COX) in cerebellum were also measured using RT-PCR and immunoblot methods. Separately, HT22 cells were used to determine the involvement of 17β-estradiol (E2) and COX in mitochondrial respiration. The genetic knockout of p38 in Purkinje neurons suppressed the mitochondrial respiration only in male mice and increased COX expression only in female mice. The inhibition of COX by sodium azide (SA) sharply suppressed mitochondrial respiration of HT22 cells in a manner that was protected by E2. These data suggest that p38 is required for the mitochondrial respiration of male mice. When p38 is below a normal level, females may maintain mitochondrial respiration through COX up-regulation. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Performance of two commercial ELISAs for detecting IgA anti-human and anti-guinea pig tissue transglutaminase antibodies.

PubMed

Abrantes-Lemos, Clarice Pires; Nakhle, Maria Cristina; Damiao, Aderson Omar Mourao Cintra; Sipahi, Aytan Miranda; Carrilho, Flair José; Cancado, Eduardo Luiz R

2010-01-01

Sensitivity and specificity of anti-human tissue transglutaminase antibodies (anti-htTGA) seem to be superior to those of anti-tissue transglutaminase of guinea pig (anti-gptTGA) for screening patients with celiac disease (CD), but there are still controversies. The aim of this study was to evaluate the performance of two INOVA ELISA kits to detect IgA anti-htTGA and anti-gptTGA in patients with and without CD. The study groups were comprised of 49 anti-endomysial antibody (EMA)-positive untreated-CD, and 123 controls (EMA-negative treated CD, EMA-negative chronic diarrhea, autoimmune hepatitis, inflammatory bowel disease and healthy people). The agreement between the two ELISAs was statistically significant in all study groups and there was no significant difference between them (92.7% agreement; kappa = 0.70; kappa p = 0.001; McNemar p = 1). All patients with serum reactivity of more than 100 units had histologic diagnosis of CD. In seven of 10 patients with treated-CD who had control biopsies, villous atrophy was still present in four who tested positive by both kits. Two of three celiacs with histologic remission tested positive for both anti-tTGA. the anti-gptTGA and anti-htTGA determination were equally efficient in identifying patients with untreated-CD with high titers of EMA. Whatever the anti-tTGA ELISA used, the reactivity above 100 units was always related to active CD diagnosed by histologic alterations in intestinal biopsies. The anti-tTGA reactivity by both kits was not only similar in determining histologic activity in the follow-up of CD after a gluten free diet, but also in identifying positive sera from the control groups, regardless if CD has been confirmed by duodenal biopsies.

Immunogenicity, efficacy and safety of Nuwiq® (human-cl rhFVIII) in previously untreated patients with severe haemophilia A-Interim results from the NuProtect Study.

PubMed

Liesner, R J; Abashidze, M; Aleinikova, O; Altisent, C; Belletrutti, M J; Borel-Derlon, A; Carcao, M; Chambost, H; Chan, A K C; Dubey, L; Ducore, J; Fouzia, N A; Gattens, M; Gruel, Y; Guillet, B; Kavardakova, N; El Khorassani, M; Klukowska, A; Lambert, T; Lohade, S; Sigaud, M; Turea, V; Wu, J K M; Vdovin, V; Pavlova, A; Jansen, M; Belyanskaya, L; Walter, O; Knaub, S; Neufeld, E J

2018-03-01

Nuwiq ® (Human-cl rhFVIII) is a fourth generation recombinant FVIII, produced in a human cell line, without chemical modification or protein fusion. No inhibitors developed in studies with Nuwiq ® in 201 previously treated patients with haemophilia A (HA). The immunogenicity, efficacy and safety of Nuwiq ® in previously untreated patients (PUPs) with severe HA are being assessed in the ongoing NuProtect study. The study, conducted across 38 centres worldwide, is evaluating 110 true PUPs of all ages and ethnicities enrolled for study up to 100 exposure days (EDs) or 5 years maximum. The primary objective is to assess the immunogenicity of Nuwiq ® (inhibitor activity ≥0.6 BU) using the Nijmegen-modified Bethesda assay at a central laboratory. Data for 66 PUPs with ≥20 EDs from a preplanned interim analysis were analysed. High-titre (HT) inhibitors developed in 8 of 66 patients after a median of 11.5 EDs (range 6-24). Five patients developed low-titre inhibitors (4 transient). The cumulative incidence (95% confidence interval) was 12.8% (4.5%, 21.2%) for HT inhibitors and 20.8% (10.7%, 31.0%) for all inhibitors. During inhibitor-free periods, median annualized bleeding rates during prophylaxis were 0 for spontaneous bleeds and 2.40 for all bleeds. Efficacy was rated as "excellent" or "good" in treating 91.8% of bleeds. Efficacy of surgical prophylaxis was "excellent" or "good" for 8 (89%) procedures and "moderate" for 1 (11%). No tolerability concerns were evident. These interim data show a cumulative incidence of 12.8% for HT inhibitors and convincing efficacy and tolerability in PUPs treated with Nuwiq ® . © 2017 The Authors. Haemophilia published by John Wiley & Sons Ltd.

Preclinical and clinical characterization of the selective 5-HT(1A) receptor antagonist DU-125530 for antidepressant treatment.

PubMed

Scorza, M C; Lladó-Pelfort, L; Oller, S; Cortés, R; Puigdemont, D; Portella, M J; Pérez-Egea, R; Alvarez, E; Celada, P; Pérez, V; Artigas, F

2012-11-01

The antidepressant efficacy of selective 5-HT reuptake inhibitors (SSRI) and other 5-HT-enhancing drugs is compromised by a negative feedback mechanism involving 5-HT(1A) autoreceptor activation by the excess 5-HT produced by these drugs in the somatodendritic region of 5-HT neurones. 5-HT(1A) receptor antagonists augment antidepressant-like effects in rodents by preventing this negative feedback, and the mixed β-adrenoceptor/5-HT(1A) receptor antagonist pindolol improves clinical antidepressant effects by preferentially interacting with 5-HT(1A) autoreceptors. However, it is unclear whether 5-HT(1A) receptor antagonists not discriminating between pre- and post-synaptic 5-HT(1A) receptors would be clinically effective. We characterized the pharmacological properties of the 5-HT(1A) receptor antagonist DU-125530 using receptor autoradiography, intracerebral microdialysis and electrophysiological recordings. Its capacity to accelerate/enhance the clinical effects of fluoxetine was assessed in a double-blind, randomized, 6 week placebo-controlled trial in 50 patients with major depression (clinicaltrials.gov identifier NCT01119430). DU-125530 showed equal (low nM) potency to displace agonist and antagonist binding to pre- and post-synaptic 5-HT(1A) receptors in rat and human brain. It antagonized suppression of 5-hydroxytryptaminergic activity evoked by 8-OH-DPAT and SSRIs in vivo. DU-125530 augmented SSRI-induced increases in extracellular 5-HT as effectively as in mice lacking 5-HT(1A) receptors, indicating a silent, maximal occupancy of pre-synaptic 5-HT(1A) receptors at the dose used. However, DU-125530 addition to fluoxetine did not accelerate nor augment its antidepressant effects. DU-125530 is an excellent pre- and post-synaptic 5-HT(1A) receptor antagonist. However, blockade of post-synaptic 5- HT(1A) receptors by DU-125530 cancels benefits obtained by enhancing pre-synaptic 5-hydroxytryptaminergic function. © 2011 The Authors. British Journal of Pharmacology © 2011 The British Pharmacological Society.

Impact of Maternal Serotonin Transporter Genotype on Placental Serotonin, Fetal Forebrain Serotonin, and Neurodevelopment

PubMed Central

Muller, Christopher L; Anacker, Allison MJ; Rogers, Tiffany D; Goeden, Nick; Keller, Elizabeth H; Forsberg, C Gunnar; Kerr, Travis M; Wender, Carly LA; Anderson, George M; Stanwood, Gregg D; Blakely, Randy D; Bonnin, Alexandre; Veenstra-VanderWeele, Jeremy

2017-01-01

Biomarker, neuroimaging, and genetic findings implicate the serotonin transporter (SERT) in autism spectrum disorder (ASD). Previously, we found that adult male mice expressing the autism-associated SERT Ala56 variant have altered central serotonin (5-HT) system function, as well as elevated peripheral blood 5-HT levels. Early in gestation, before midbrain 5-HT projections have reached the cortex, peripheral sources supply 5-HT to the forebrain, suggesting that altered maternal or placenta 5-HT system function could impact the developing embryo. We therefore used different combinations of maternal and embryo SERT Ala56 genotypes to examine effects on blood, placenta and embryo serotonin levels and neurodevelopment at embryonic day E14.5, when peripheral sources of 5-HT predominate, and E18.5, when midbrain 5-HT projections have reached the forebrain. Maternal SERT Ala56 genotype was associated with decreased placenta and embryonic forebrain 5-HT levels at E14.5. Low 5-HT in the placenta persisted, but forebrain levels normalized by E18.5. Maternal SERT Ala56 genotype effects on forebrain 5-HT levels were accompanied by a broadening of 5-HT-sensitive thalamocortical axon projections. In contrast, no effect of embryo genotype was seen in concepti from heterozygous dams. Blood 5-HT levels were dynamic across pregnancy and were increased in SERT Ala56 dams at E14.5. Placenta RNA sequencing data at E14.5 indicated substantial impact of maternal SERT Ala56 genotype, with alterations in immune and metabolic-related pathways. Collectively, these findings indicate that maternal SERT function impacts offspring placental 5-HT levels, forebrain 5-HT levels, and neurodevelopment. PMID:27550733

Protein disulfide isomerase mediates glutathione depletion-induced cytotoxicity.

PubMed

Okada, Kazushi; Fukui, Masayuki; Zhu, Bao-Ting

2016-08-26

Glutathione depletion is a distinct cause underlying many forms of pathogenesis associated with oxidative stress and cytotoxicity. Earlier studies showed that glutamate-induced glutathione depletion in immortalized murine HT22 hippocampal neuronal cells leads to accumulation of reactive oxygen species (ROS) and ultimately cell death, but the precise mechanism underlying these processes is not clear. Here we show that during the induction of glutathione depletion, nitric oxide (NO) accumulation precedes ROS accumulation. While neuronal NO synthase (nNOS) in untreated HT22 cells exists mostly as a monomer, glutathione depletion results in increased formation of the dimer nNOS, accompanied by increases in the catalytic activity. We identified that nNOS dimerization is catalyzed by protein disulfide isomerase (PDI). Inhibition of PDI's isomerase activity effectively abrogates glutathione depletion-induced conversion of monomer nNOS into dimer nNOS, accumulation of NO and ROS, and cytotoxicity. Furthermore, we found that PDI is present in untreated cells in an inactive S-nitrosylated form, which becomes activated following glutathione depletion via S-denitrosylation. These results reveal a novel role for PDI in mediating glutathione depletion-induced oxidative cytotoxicity, as well as its role as a valuable therapeutic target for protection against oxidative cytotoxicity. Copyright © 2016. Published by Elsevier Inc.

Axons take a dive

PubMed Central

Tong, Cheuk Ka; Cebrián-Silla, Arantxa; Paredes, Mercedes F; Huang, Eric J; García-Verdugo, Jose Manuel; Alvarez-Buylla, Arturo

2015-01-01

In the walls of the lateral ventricles of the adult mammalian brain, neural stem cells (NSCs) and ependymal (E1) cells share the apical surface of the ventricular–subventricular zone (V–SVZ). In a recent article, we show that supraependymal serotonergic (5HT) axons originating from the raphe nuclei in mice form an extensive plexus on the walls of the lateral ventricles where they contact E1 cells and NSCs. Here we further characterize the contacts between 5HT supraependymal axons and E1 cells in mice, and show that suprependymal axons tightly associated to E1 cells are also present in the walls of the human lateral ventricles. These observations raise interesting questions about the function of supraependymal axons in the regulation of E1 cells. PMID:26413556

Effects of Swertia japonica extract and its main compound swertiamarin on gastric emptying and gastrointestinal motility in mice.

PubMed

Kimura, Yoshiyuki; Sumiyoshi, Maho

2011-09-01

The Swertia japonica is used clinically as a remedy for gastrointestinal symptoms in Japan. We examined the effects of a S. japonica and swertiamarin on gastric emptying and gastrointestinal motility in atropine-, dopamine-, and 5-hydroxytryptamine (5-HT)-treated mice. All three preparations inhibited reductions in gastric emptying and gastrointestinal motility induced by dopamine (1mg/kg, intraperitoneal injection, ip). Neither the powder, swertiamarin, nor itopride had any effect on the reductions in gastric emptying and gastrointestinal motility caused by 5-HT (4 mg/kg, ip). These findings suggest that the powder and swertiamarin stimulate gastric emptying and gastrointestinal motility by inhibiting the dopamine D(2) receptor. Copyright © 2011 Elsevier B.V. All rights reserved.

Limonene inhibits methamphetamine-induced locomotor activity via regulation of 5-HT neuronal function and dopamine release.

PubMed

Yun, Jaesuk

2014-05-15

Methamphetamine is a psychomotor stimulant that produces hyperlocomotion in rodents. Limonene (a cyclic terpene from citrus essential oils) has been reported to induce sedative effects. In this study, we demonstrated that limonene administration significantly inhibited serotonin (5-hydroxytryptamine, 5-HT)-induced head twitch response in mice. In rats, pretreatment with limonene decreased hyperlocomotion induced by methamphetamine injection. In addition, limonene reversed the increase in dopamine levels in the nucleus accumbens of rats given methamphetamine. These results suggest that limonene may inhibit stimulant-induced behavioral changes via regulating dopamine levels and 5-HT receptor function. Copyright © 2013 Elsevier GmbH. All rights reserved.

Immunoregulatory activity by daucosterol, a beta-sitosterol glycoside, induces protective Th1 immune response against disseminated Candidiasis in mice.

PubMed

Lee, Jue-Hee; Lee, Ju Young; Park, Ji Hye; Jung, Hye Sil; Kim, Ju Sun; Kang, Sam Sik; Kim, Yeong Shik; Han, Yongmoon

2007-05-10

In the present study, we investigated immunomodulatory effect of daucosterol, a beta-sitosterol glycoside, against disseminated candidiasis caused by Candida albicans. Results showed that direct interaction of daucosterol with C. albicans yeast cells resulted in no growth-inhibition by in vitro susceptibility analysis. In contrast, mice given daucosterol (DS) intraperitoneally before intravenous challenge with live C. albicans yeast cells survived longer than DS-untreated control mice against disseminated candidiasis (P<0.05). By assessment of the fungal CFU in kidneys, DS-treated mice before the challenge developed about 81% fewer kidney CFU than untreated controls. This protection was removable by pretreatment of mice with anti-CD4+ antibody before the DS-treatment and challenge with the yeast. However, the protection was transferable by the CD4+ T cells from DS-treated mice not infected with the yeast. ELISA analysis revealed there were predominant production of IFNgamma and IL-2 cytokines as compared to IL-4, and IL-10 productions in DS-treated mice. By treatment of DS-given mice with anti-mouse IFNgamma, the protection was also abolished. Our studies show that DS protects mice against disseminated candidiasis by the CD4+ Th1 immune response.

Gut microbiota recovery and immune response in ampicillin-treated mice.

PubMed

Castro-Mejía, Josué L; Jakesevic, Maja; Fabricius, Niels F; Krych, Łukasz; Nielsen, Dennis S; Kot, Witold; Bendtsen, Katja M; Vogensen, Finn K; Hansen, Camilla H F; Hansen, Axel K

2018-06-01

Ampicillin is applied in rodents to induce a temporarily depleted microbiota. To elucidate whether bacteria are just temporarily suppressed or fully eliminated, and how this affects the re-colonisation process, we compared the microbiota and immune system in conventionally housed untreated mice with newly weaned ampicillin treated mice subsequently housed in either a microbe containing environment or in an isolator with only host associated suppressed bacteria to recolonize the gut. Two weeks ampicillin treatment induced a seemingly germ-free state with no bacterial DNA to reveal. Four weeks after treatment caeca were still significantly enlarged in both treated groups, but bacteria re-appeared even in isolator housed mice. While some suppressed bacteria were able to recover and even dominate the community, the abundances and composition were far from the untreated mice and differed between isolator and conventional housing. The treatment reduced the innate cytokine expressions at least for three weeks after treatment, and had a non-lasting reducing impact on the regulatory T cells, and a more lasting impact on the natural killer T cells. We conclude that temporary ampicillin treatment suppresses the majority but does not eliminate all the gut microbiota members. The re-colonisation process is as such influenced by both suppressed host associated bacteria and by environmental bacteria. Treated mice do not re-obtain a complex gut microbiota comparable to untreated mice, and the immune response and gut morphology reflect this. This is a concern when comparing host parameters sensitive to microbial regulation after an antibiotic-induced temporarily "germ-free" state. Copyright © 2018 Elsevier Ltd. All rights reserved.

Progesterone neuroprotection in the Wobbler mouse, a genetic model of spinal cord motor neuron disease.

PubMed

Gonzalez Deniselle, María Claudia; López-Costa, Juan José; Saavedra, Jorge Pecci; Pietranera, Luciana; Gonzalez, Susana L; Garay, Laura; Guennoun, Rachida; Schumacher, Michael; De Nicola, Alejandro F

2002-12-01

Motor neuron degeneration characterizes the spinal cord of patients with amyotrophic lateral sclerosis and the Wobbler mouse mutant. Considering that progesterone (PROG) provides neuroprotection in experimental ischemia and injury, its potential role in neurodegeneration was studied in the murine model. Two-month-old symptomatic Wobbler mice were left untreated or received sc a 20-mg PROG implant for 15 days. Both light and electron microscopy of Wobbler mice spinal cord showed severely affected motor neurons with profuse cytoplasmic vacuolation of the endoplasmic reticulum and/or Golgi apparatus and ruptured mitochondria with damaged cristae, a profile indicative of a type II cytoplasmic form of cell death. In contrast to untreated mice, neuropathology was less severe in Wobbler mice receiving PROG; including a reduction of vacuolation and of the number of vacuolated cells and better conservation of the mitochondrial ultrastructure. In biochemical studies, we determined the mRNA for the alpha3 subunit of Na,K-ATPase, a neuronal enzyme controlling ion fluxes, neurotransmission, membrane potential, and nutrient uptake. In untreated Wobbler mice, mRNA levels in motor neurons were reduced by half compared to controls, whereas PROG treatment of Wobbler mice restored the expression of alpha3 subunit Na,K-ATPase mRNA. Therefore, PROG was able to rescue motor neurons from degeneration, based on recovery of histopathological abnormalities and of mRNA levels of the sodium pump. However, because the gene mutation in Wobbler mice is still unknown, further studies are needed to unveil the action of PROG and the mechanism of neuronal death in this genetic model of neurodegeneration.

Serotonin engages an anxiety and fear-promoting circuit in the extended amygdala.

PubMed

Marcinkiewcz, Catherine A; Mazzone, Christopher M; D'Agostino, Giuseppe; Halladay, Lindsay R; Hardaway, J Andrew; DiBerto, Jeffrey F; Navarro, Montserrat; Burnham, Nathan; Cristiano, Claudia; Dorrier, Cayce E; Tipton, Gregory J; Ramakrishnan, Charu; Kozicz, Tamas; Deisseroth, Karl; Thiele, Todd E; McElligott, Zoe A; Holmes, Andrew; Heisler, Lora K; Kash, Thomas L

2016-09-01

Serotonin (also known as 5-hydroxytryptamine (5-HT)) is a neurotransmitter that has an essential role in the regulation of emotion. However, the precise circuits have not yet been defined through which aversive states are orchestrated by 5-HT. Here we show that 5-HT from the dorsal raphe nucleus (5-HT DRN ) enhances fear and anxiety and activates a subpopulation of corticotropin-releasing factor (CRF) neurons in the bed nucleus of the stria terminalis (CRF BNST ) in mice. Specifically, 5-HT DRN projections to the BNST, via actions at 5-HT 2C receptors (5-HT 2C Rs), engage a CRF BNST inhibitory microcircuit that silences anxiolytic BNST outputs to the ventral tegmental area and lateral hypothalamus. Furthermore, we demonstrate that this CRF BNST inhibitory circuit underlies aversive behaviour following acute exposure to selective serotonin reuptake inhibitors (SSRIs). This early aversive effect is mediated via the corticotrophin-releasing factor type 1 receptor (CRF 1 R, also known as CRHR1), given that CRF 1 R antagonism is sufficient to prevent acute SSRI-induced enhancements in aversive learning. These results reveal an essential 5-HT DRN →CRF BNST circuit governing fear and anxiety, and provide a potential mechanistic explanation for the clinical observation of early adverse events to SSRI treatment in some patients with anxiety disorders.

A novel regulator of angiogenesis in endothelial cells: 5-hydroxytriptamine 4 receptor.

PubMed

Profirovic, Jasmina; Strekalova, Elena; Urao, Norifumi; Krbanjevic, Aleksandar; Andreeva, Alexandra V; Varadarajan, Sudhahar; Fukai, Tohru; Hen, René; Ushio-Fukai, Masuko; Voyno-Yasenetskaya, Tatyana A

2013-01-01

The 5-hydroxytryptamine type 4 receptor (5-HT(4)R) regulates many physiological processes, including learning and memory, cognition, and gastrointestinal motility. Little is known about its role in angiogenesis. Using mouse hindlimb ischemia model of angiogenesis, we observed a significant reduction of limb blood flow recovery 14 days after ischemia and a decrease in density of CD31-positive vessels in adductor muscles in 5-HT(4)R(-/-) mice compared to wild type littermates. Our in vitro data indicated that 5-HT(4)R endogenously expressed in endothelial cells (ECs) may promote angiogenesis. Inhibition of the receptor with 5-HT(4)R antagonist RS 39604 reduced EC capillary tube formation in the reconstituted basement membrane. Using Boyden chamber migration assay and wound healing "scratch" assay, we demonstrated that RS 39604 treatment significantly suppressed EC migration. Transendothelial resistance measurement and immunofluorescence analysis showed that a 5-HT(4)R agonist RS 67333 led to an increase in endothelial permeability, actin stress fiber and interendothelial gap formation. Importantly, we provided the evidence that 5-HT(4)R-regulated EC migration may be mediated by Gα13 and RhoA. Our results suggest a prominent role of 5-HT(4)R in promoting angiogenesis and identify 5-HT(4)R as a potential therapeutic target for modulating angiogenesis under pathological conditions.

Serotonin 5-HT7 receptor agents: structure-activity relationships and potential therapeutic applications in central nervous system disorders

PubMed Central

Leopoldo, Marcello; Lacivita, Enza; Berardi, Francesco; Perrone, Roberto; Hedlund, Peter B.

2010-01-01

Since its discovery in the 1940s in serum, the mammalian intestinal mucosa, and in the central nervous system, serotonin (5-HT) has been shown to be involved in virtually all cognitive and behavioral human functions, and alterations in its neurochemistry have been implicated in the etiology of a plethora of neuropsychiatric disorders. The cloning of 5-HT receptor subtypes has been of importance in enabling them to be classified as specific protein molecules encoded by specific genes. The 5-HT7 receptor is the most recently classified member of the serotonin receptor family. Since its identification, it has been the subject of intense research efforts driven by its presence in functionally relevant regions of the brain. The availability of some selective antagonists and agonists, in combination with genetically modified mice lacking the 5-HT7 receptor, has allowed for a better understanding of the pathophysiological role of this receptor. This paper reviews data on localization and pharmacological properties of the 5-HT7 receptor, and summarizes the results of structure-activity relationship studies aimed at the discovery of selective 5-HT7 receptor ligands. Additionally, an overview of the potential therapeutic applications of 5-HT7 receptor agonists and antagonists in central nervous system disorders is presented. PMID:20923682

Tolerance and Cross-Tolerance to Head Twitch Behavior Elicited by Phenethylamine- and Tryptamine-Derived Hallucinogens in Mice

PubMed Central

Smith, Douglas A.; Bailey, Jessica M.; Williams, Diarria

2014-01-01

The serotonin 5-hydroxytryptamine 2A (5-HT2A) receptor is a potential therapeutic target to a host of neuropsychiatric conditions, but agonist actions at this site are linked to abuse-related hallucinogenic effects that may limit therapeutic efficacy of chronic drug administration. Tolerance to some effects of hallucinogens has been observed in humans and laboratory animals, but the understanding of tolerance and cross-tolerance between distinct structural classes of hallucinogens is limited. Here, we used the drug-elicited head twitch response (HTR) in mice to assess the development of tolerance and cross-tolerance with two phenethylamine-derived [DOI (2,5-dimethoxy-4-iodoamphetamine) and 2C-T-7 (2,5-dimethoxy-4-propylthiophenethylamine)] and two tryptamine-derived [DPT (N,N-dipropyltryptamine) and DIPT (N,N-diisopropyltryptamine)] drugs with agonist affinity for 5-HT2A receptors. Tolerance developed to HTR elicited by daily DOI or 2C-T-7, but not to HTR elicited by DPT or DIPT. DOI-elicited tolerance was not surmountable with dose, and a similar insurmountable cross-tolerance was evident when DOI-tolerant mice were tested with various doses of 2C-T-7 or DPT. These studies suggest that the use of phenethylamine-derived hallucinogens as therapeutic agents may be limited not only by their abuse potential, but also by the rapid development of tolerance that would likely be maintained even if a patient were switched to a different 5-HT2A agonist medication from a distinct structural class. However, these experiments also imply that tryptamine-derived hallucinogens might have a reduced potential for tolerance development, compared with phenethylamine-derived 5-HT2A agonists, and might therefore be more suitable for chronic administration in a therapeutic context. PMID:25271256

A PPAR-gamma agonist protects from radiation-induced intestinal toxicity

PubMed Central

Sottili, Mariangela; Gerini, Chiara; Desideri, Isacco; Bastida, Cinzia; Pallotta, Stefania; Castiglione, Francesca; Bonomo, Pierluigi; Meattini, Icro; Greto, Daniela; Cappelli, Sabrina; Di Brina, Lucia; Loi, Mauro; Biti, Giampaolo; Livi, Lorenzo

2016-01-01

Objective Because of its anti-inflammatory, anti-fibrotic, anti-apoptotic and anti-neoplastic properties, the PPAR-γ agonist rosiglitazone is an interesting drug for investigating for use in the prevention and treatment of radiation-induced intestinal damage. We aimed to evaluate the radioprotective effect of rosiglitazone in a murine model of acute intestinal damage, assessing whether radioprotection is selective for normal tissues or also occurs in tumour cells. Methods Mice were total-body irradiated (12 Gy), with or without rosiglitazone (5 mg/kg/day). After 24 and 72 hours, mice were sacrificed and the jejunum was collected. HT-29 human colon cancer cells were irradiated with a single dose of 2 (1000 cells), 4 (1500 cells) or 6 (2000 cells) Gy, with or without adding rosiglitazone (20 µM) 1 hour before irradiation. HT-29-xenografted CD1 mice were irradiated (16 Gy) with or without rosiglitazone; tumour volumes were measured for 33 days. Results Rosiglitazone markedly reduced histological signs of altered bowel structures, that is, villi shortening, submucosal thickening, necrotic changes in crypts, oedema, apoptosis, and inflammatory infiltrate induced by irradiation. Rosiglitazone significantly decreased p-NF-kB p65 phosphorylation and TGFβ protein expression at 24 and 72 hours post-irradiation and significantly decreased gene expression of Collagen1, Mmp13, Tnfα and Bax at 24 hours and p53 at 72 hours post-irradiation. Rosiglitazone reduced HT-29 clonogenic survival, but only produced a slight reduction of xenograft tumour growth. Conclusion Rosiglitazone exerts a protective effect on normal tissues and reduces alterations in bowel structures and inflammation in a radiation-induced bowel toxicity model, without interfering with the radiation effect on HT-29 cancer cells. PPAR-γ agonists should be further investigated for their application in abdominal and pelvic irradiation. PMID:28344789

Transglutaminase 2 overexpression induces depressive-like behavior and impaired TrkB signaling in mice

PubMed Central

Pandya, Chirayu D; Hoda, Nasrul; Crider, Amanda; Peter, Diya; Kutiyanawalla, Ammar; Kumar, Sanjiv; Ahmed, Anthony O; Turecki, Gustavo; Hernandez, Caterina M; Terry, Alvin V

2016-01-01

Serotonin (5-HT) and brain derived neurotrophic factor (BDNF) are two signaling molecules that play important regulatory roles in the development and plasticity of neural circuits that are known to be altered in depression. However, the mechanism by which 5-HT regulates BDNF signaling is unknown. In the present study, we found that 5-HT treatment increases BDNF receptor, TrkB (tropomyosin related kinase B) levels in mouse primary cortical neurons via a Rac1 (RAS-related C3 botulinum toxin substrate 1)-dependent mechanism. Significant increases in the levels of transglutaminase 2 (TG2, which is implicated in transamidation of 5-HT to Rac1) are observed in the mouse prefrontal cortex (PFC) following chronic exposure to stress. We also found that TG2 levels are increased in the postmortem PFC of depressed suicide subjects relative to matched controls. Moreover, in mice, neuronal overexpression of TG2 resulted in the atrophy of neurons and reduced levels of TrkB in the PFC as well as a depressive-like phenotype. Overexpression of TG2 in mouse cortical neurons reduced TrkB levels as a result of impaired endocytosis of TrkB. TG2 inhibition by either a viral particle or pharmacological approach attenuated behavioral deficits caused by chronic unpredictable stress. Moreover, the overexpression of TrkB in the mouse PFC ameliorated the depressive-like phenotype of TG2 overexpressed mice. Taken together, these postmortem and preclinical findings identify TG2 as a critical mediator of the altered TrkB expression and depressive-like behaviors associated with chronic exposure to stress and suggest that TG2 may represent a novel therapeutic target in depression. PMID:27620841

Pharmacologic rescue of motivational deficit in an animal model of the negative symptoms of schizophrenia.

PubMed

Simpson, Eleanor H; Kellendonk, Christoph; Ward, Ryan D; Richards, Vanessa; Lipatova, Olga; Fairhurst, Stephen; Kandel, Eric R; Balsam, Peter D

2011-05-15

Deficits in incentive motivation, the energizing of behavior in pursuit of a goal, occur in many psychiatric disorders including schizophrenia. We previously reported deficits in both cognition and incentive motivation in a transgenic mouse model of increased striatal-specific dopamine D2 receptor (D2R) density (D2R-OE mice). This molecular alteration is observed in patients with schizophrenia, making D2R-OE mice a suitable system to study the cellular and molecular mechanisms of motivation and avolition, as well as a tool for testing potential therapies against motivational deficits. Behavioral studies using operant conditioning methods were performed both to further characterize the incentive motivation deficit in D2R-OE mice and test a novel pharmacological treatment target that arose from an unbiased expression study performed using gene chips and was validated by quantitative reverse transcription polymerase chain reaction, in situ hybridization, and immunohistochemistry. The reluctance of D2R-OE mice to work is due neither to intolerance for low rates of reward, decreased reactivity to reward, nor increased sensitivity to satiety or fatigue but to a difference in willingness to work for reward. As in patients with schizophrenia, this deficit was not ameliorated by D2R blockade, suggesting that reversal of the motivational deficit by switching off the transgene results from molecular changes downstream of D2R overexpression. We observed a reversible increase in serotonin subtype 2C (5-HT2C) receptor expression in D2R-OE mice. Systemic injection of a 5-HT2C receptor antagonist increased incentive motivation in D2R-OE and control mice. We propose that targeting 5-HT2C receptors may be a useful approach to modulate incentive motivation in psychiatric illness. Copyright © 2011 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

CPB-K mice a mouse model of schizophrenia? Differences in dopaminergic, serotonergic and behavioral markers compared to BALB/cJ mice.

PubMed

Panther, P; Nullmeier, S; Dobrowolny, H; Schwegler, H; Wolf, R

2012-04-21

Schizophrenia is characterized by disturbances in social behavior, sensorimotor gating and cognitive function, that are discussed to be caused by a termination of different transmitter systems. Beside morphological alterations in cortical and subcortical areas reduced AMPA- NMDA-, 5-HT2-receptor densities and increased 5-HT1-receptor densities are found in the hippocampus.The two inbred mouse strains CPB-K and BALB/cJ are known to display considerable differences in cognitive function and prepulse inhibition, a stable marker of sensorimotor gating. Furthermore, CPB-K mice exhibit lower NMDA-, AMPA- and increased 5-HT-receptor densities in the hippocampus as compared to BALB/cJ mice. We investigated both mouse strains in social interaction test for differences in social behavior and with immuncytochemical approaches for alterations of dopaminergic and serotonergic parameters. Our results can be summarized as follows: compared to BALB/cJ, CPB-K mice showed:(1) significantly reduced traveling distance and number of contacts in social interaction test, (2) differences in the number of serotonin transporter-immunoreactive neurons and volume of raphe nuclei and a lower serotonergic fiber density in the ventral and dorsal hippocampal subfields CA1 and CA3, (3) no alterations of dopaminergic markers like neuron number, neuron density and volume in subregions of substantia nigra and ventral tegmental area, but a significantly higher dopaminergic fiber density in the dorsal hippocampus, the ventral hippocampus of CA1 and gyrus dentatus, (4) no significant differences in serotonergic and dopaminergic fiber densities in the amygdala.Based on our results and previous studies, CPB-K mice compared to BALB/cJ may serve as an important model to understand the interaction of the serotonergic and dopaminergic system and their impact on sensorimotor gating and cognitive function as related to neuropsychiatric disorders like schizophrenia. 2012 Elsevier B.V. All rights reserved.

Gold-nanofève surface-enhanced Raman spectroscopy visualizes hypotaurine as a robust anti-oxidant consumed in cancer survival.

PubMed

Shiota, Megumi; Naya, Masayuki; Yamamoto, Takehiro; Hishiki, Takako; Tani, Takeharu; Takahashi, Hiroyuki; Kubo, Akiko; Koike, Daisuke; Itoh, Mai; Ohmura, Mitsuyo; Kabe, Yasuaki; Sugiura, Yuki; Hiraoka, Nobuyoshi; Morikawa, Takayuki; Takubo, Keiyo; Suina, Kentaro; Nagashima, Hideaki; Sampetrean, Oltea; Nagano, Osamu; Saya, Hideyuki; Yamazoe, Shogo; Watanabe, Hiroyuki; Suematsu, Makoto

2018-04-19

Gold deposition with diagonal angle towards boehmite-based nanostructure creates random arrays of horse-bean-shaped nanostructures named gold-nanofève (GNF). GNF generates many electromagnetic hotspots as surface-enhanced Raman spectroscopy (SERS) excitation sources, and enables large-area visualization of molecular vibration fingerprints of metabolites in human cancer xenografts in livers of immunodeficient mice with sufficient sensitivity and uniformity. Differential screening of GNF-SERS signals in tumours and those in parenchyma demarcated tumour boundaries in liver tissues. Furthermore, GNF-SERS combined with quantum chemical calculation identified cysteine-derived glutathione and hypotaurine (HT) as tumour-dominant and parenchyma-dominant metabolites, respectively. CD44 knockdown in cancer diminished glutathione, but not HT in tumours. Mechanisms whereby tumours sustained HT under CD44-knockdown conditions include upregulation of PHGDH, PSAT1 and PSPH that drove glycolysis-dependent activation of serine/glycine-cleavage systems to provide one-methyl group for HT synthesis. HT was rapidly converted into taurine in cancer cells, suggesting that HT is a robust anti-oxidant for their survival under glutathione-suppressed conditions.

Dissociating the therapeutic effects of environmental enrichment and exercise in a mouse model of anxiety with cognitive impairment

PubMed Central

Rogers, J; Vo, U; Buret, LS; Pang, TY; Meiklejohn, H; Zeleznikow-Johnston, A; Churilov, L; van den Buuse, M; Hannan, AJ; Renoir, T

2016-01-01

Clinical evidence indicates that serotonin-1A receptor (5-HT1AR) gene polymorphisms are associated with anxiety disorders and deficits in cognition. In animal models, exercise (Ex) and environmental enrichment (EE) can change emotionality-related behaviours, as well as enhance some aspects of cognition and hippocampal neurogenesis. We investigated the effects of Ex and EE (which does not include running wheels) on cognition and anxiety-like behaviours in wild-type (WT) and 5-HT1AR knock-out (KO) mice. Using an algorithm-based classification of search strategies in the Morris water maze, we report for we believe the first time that Ex increased the odds for mice to select more hippocampal-dependent strategies. In the retention probe test, Ex (but not EE) corrected long-term spatial memory deficits displayed by KO mice. In agreement with these findings, only Ex increased hippocampal cell survival and BDNF protein levels. However, only EE (but not Ex) modified anxiety-like behaviours, demonstrating dissociation between improvements in cognition and innate anxiety. EE enhanced hippocampal cell proliferation in WT mice only, suggesting a crucial role for intact serotonergic signalling in mediating this effect. Together, these results demonstrate differential effects of Ex vs EE in a mouse model of anxiety with cognitive impairment. Overall, the 5-HT1AR does not seem to be critical for those behavioural effects to occur. These findings will have implications for our understanding of how Ex and EE enhance experience-dependent plasticity, as well as their differential impacts on anxiety and cognition. PMID:27115125

Effect of Lactobacillus plantarum Tennozu-SU2 on Salmonella Typhimurium Infection in Human Enterocyte-Like HT-29-Luc Cells and BALB/c Mice.

PubMed

Hirano, Shino; Yokota, Yasushi; Eda, Mika; Kuda, Takashi; Shikano, Ayane; Takahashi, Hajime; Kimura, Bon

2017-03-01

The probiotic properties and inhibitory effect on Salmonella Typhimurium adhesion on human enterocyte-like HT-29-Luc cells of three Lactobacillus plantarum strains isolated from fermented fish, beach sand and a coastal plant were determined. Compared with the type strain L. plantarum NBRC 15891 T , which was isolated from pickled cabbage, L. plantarum Tennozu-SU2 isolated from the acorn of a coastal tree showed high autoaggregation in de Man, Rogosa and Sharpe (MRS) broth and an antagonistic effect against S. Typhimurium in brain heart infusion (BHI) broth. Furthermore, heat-killed L. plantarum Tennozu-SU2 cells inhibited S. Typhimurium adhesion on HT-29-Luc cells. Both live and heat-killed L. plantarum Tennozu-SU2 cells showed an inhibitory effect on gut colonisation in BALB/c mice, as assessed by viable Salmonella count in faecal samples and by invasion into liver and spleen tissues. The properties shown in this study suggest that L. plantarum Tennozu-SU2 is useful as a starter and probiotic bacteria in functional food material.

The Role of 5-HT3 Receptors in Signaling from Taste Buds to Nerves.

PubMed

Larson, Eric D; Vandenbeuch, Aurelie; Voigt, Anja; Meyerhof, Wolfgang; Kinnamon, Sue C; Finger, Thomas E

2015-12-02

Activation of taste buds triggers the release of several neurotransmitters, including ATP and serotonin (5-hydroxytryptamine; 5-HT). Type III taste cells release 5-HT directly in response to acidic (sour) stimuli and indirectly in response to bitter and sweet tasting stimuli. Although ATP is necessary for activation of nerve fibers for all taste stimuli, the role of 5-HT is unclear. We investigated whether gustatory afferents express functional 5-HT3 receptors and, if so, whether these receptors play a role in transmission of taste information from taste buds to nerves. In mice expressing GFP under the control of the 5-HT(3A) promoter, a subset of cells in the geniculate ganglion and nerve fibers in taste buds are GFP-positive. RT-PCR and in situ hybridization confirmed the presence of 5-HT(3A) mRNA in the geniculate ganglion. Functional studies show that only those geniculate ganglion cells expressing 5-HT3A-driven GFP respond to 10 μM 5-HT and this response is blocked by 1 μM ondansetron, a 5-HT3 antagonist, and mimicked by application of 10 μM m-chlorophenylbiguanide, a 5-HT3 agonist. Pharmacological blockade of 5-HT3 receptors in vivo or genetic deletion of the 5-HT3 receptors reduces taste nerve responses to acids and other taste stimuli compared with controls, but only when urethane was used as the anesthetic. We find that anesthetic levels of pentobarbital reduce taste nerve responses apparently by blocking the 5-HT3 receptors. Our results suggest that 5-HT released from type III cells activates gustatory nerve fibers via 5-HT3 receptors, accounting for a significant proportion of the neural taste response. Copyright © 2015 the authors 0270-6474/15/3515984-12$15.00/0.

Dorsal Raphe Serotonin Neurons Mediate CO2-Induced Arousal from Sleep.

PubMed

Smith, Haleigh R; Leibold, Nicole K; Rappoport, Daniel A; Ginapp, Callie M; Purnell, Benton S; Bode, Nicole M; Alberico, Stephanie L; Kim, Young-Cho; Audero, Enrica; Gross, Cornelius T; Buchanan, Gordon F

2018-02-21

Arousal from sleep in response to CO 2 is a critical protective phenomenon. Dysregulation of CO 2 -induced arousal contributes to morbidity and mortality from prevalent diseases, such as obstructive sleep apnea and sudden infant death syndrome. Despite the critical nature of this protective reflex, the precise mechanism for CO 2 -induced arousal is unknown. Because CO 2 is a major regulator of breathing, prevailing theories suggest that activation of respiratory chemo- and mechano-sensors is required for CO 2 -induced arousal. However, populations of neurons that are not involved in the regulation of breathing are also chemosensitive. Among these are serotonin (5-HT) neurons in the dorsal raphe nucleus (DRN) that comprise a component of the ascending arousal system. We hypothesized that direct stimulation of these neurons with CO 2 could cause arousal from sleep independently of enhancing breathing. Dialysis of CO 2 -rich acidified solution into DRN, but not medullary raphe responsible for modulating breathing, caused arousal from sleep. Arousal was lost in mice with a genetic absence of 5-HT neurons, and with acute pharmacological or optogenetic inactivation of DRN 5-HT neurons. Here we demonstrate that CO 2 can cause arousal from sleep directly, without requiring enhancement of breathing, and that chemosensitive 5-HT neurons in the DRN critically mediate this arousal. Better understanding mechanisms underlying this protective reflex may lead to interventions to reduce disease-associated morbidity and mortality. SIGNIFICANCE STATEMENT Although CO 2 -induced arousal is critical to a number of diseases, the specific mechanism is not well understood. We previously demonstrated that serotonin (5-HT) neurons are important for CO 2 -induced arousal, as mice without 5-HT neurons do not arouse to CO 2 Many have interpreted this to mean that medullary 5-HT neurons that regulate breathing are important in this arousal mechanism. Here we found that direct application of CO 2 -rich aCSF to the dorsal raphe nucleus, but not the medullary raphe, causes arousal from sleep, and that this arousal was lost with genetic ablation or acute inhibition of 5-HT neurons. We propose that 5-HT neurons in the dorsal raphe nucleus can be activated directly by CO 2 to cause arousal independently of respiratory activation. Copyright © 2018 the authors 0270-6474/18/381915-11$15.00/0.

Principal component analysis for the comparison of metabolic profiles from human rectal cancer biopsies and colorectal xenografts using high-resolution magic angle spinning 1H magnetic resonance spectroscopy

PubMed Central

Seierstad, Therese; Røe, Kathrine; Sitter, Beathe; Halgunset, Jostein; Flatmark, Kjersti; Ree, Anne H; Olsen, Dag Rune; Gribbestad, Ingrid S; Bathen, Tone F

2008-01-01

Background This study was conducted in order to elucidate metabolic differences between human rectal cancer biopsies and colorectal HT29, HCT116 and SW620 xenografts by using high-resolution magnetic angle spinning (MAS) magnetic resonance spectroscopy (MRS) and for determination of the most appropriate human rectal xenograft model for preclinical MR spectroscopy studies. A further aim was to investigate metabolic changes following irradiation of HT29 xenografts. Methods HR MAS MRS of tissue samples from xenografts and rectal biopsies were obtained with a Bruker Avance DRX600 spectrometer and analyzed using principal component analysis (PCA) and partial least square (PLS) regression analysis. Results and conclusion HR MAS MRS enabled assignment of 27 metabolites. Score plots from PCA of spin-echo and single-pulse spectra revealed separate clusters of the different xenografts and rectal biopsies, reflecting underlying differences in metabolite composition. The loading profile indicated that clustering was mainly based on differences in relative amounts of lipids, lactate and choline-containing compounds, with HT29 exhibiting the metabolic profile most similar to human rectal cancers tissue. Due to high necrotic fractions in the HT29 xenografts, radiation-induced changes were not detected when comparing spectra from untreated and irradiated HT29 xenografts. However, PLS calibration relating spectral data to the necrotic fraction revealed a significant correlation, indicating that necrotic fraction can be assessed from the MR spectra. PMID:18439252

IGF-I treatment improves the functional properties of fast- and slow-twitch skeletal muscles from dystrophic mice.

PubMed

Lynch, G S; Cuffe, S A; Plant, D R; Gregorevic, P

2001-04-01

Although insulin-like growth factor-I (IGF-I) has been proposed for use by patients suffering from muscle wasting conditions, few studies have investigated the functional properties of dystrophic skeletal muscle following IGF-I treatment. 129P1 ReJ-Lama2(dy) (129 ReJ dy/dy) dystrophic mice suffer from a deficiency in the structural protein, laminin, and exhibit severe muscle wasting and weakness. We tested the hypothesis that 4 weeks of IGF-I treatment ( approximately 2 mg/kg body mass, 50 g/h via mini-osmotic pump, subcutaneously) would increase the mass and force producing capacity of skeletal muscles from dystrophic mice. IGF-I treatment increased the mass of the extensor digitorum longus (EDL) and soleus muscles of dystrophic mice by 20 and 29%, respectively, compared with untreated dystrophic mice (administered saline-vehicle only). Absolute maximum force (P(o)) of the EDL and soleus muscle was increased by 40 and 32%, respectively, following IGF-I treatment. Specific P(o) (sP(o)) was increased by 23% in the EDL muscles of treated compared with untreated mice, but in the soleus muscle sP(o) was unchanged. IGF-I treatment increased the proportion of type IIB and type IIA fibres and decreased the proportion of type I fibres in the EDL muscles of dystrophic mice. In the soleus muscles of dystrophic mice, IGF-I treatment increased the proportion of type IIA fibres and decreased the proportion of type I fibres. Average fibre cross-sectional area was increased in the EDL and soleus muscles of treated compared with untreated mice. We conclude that IGF-I treatment ameliorates muscle wasting and improves the functional properties of skeletal muscles of dystrophic mice. The findings have important implications for the role of IGF-I in ameliorating muscle wasting associated with the muscular dystrophies.

Effects of a traditional Chinese herbal medicine, Kanzo-bushi-to, on the resistance of thermally injured mice infected with herpes simplex virus type 1.

PubMed

Matsuo, R; Ball, M A; Kobayashi, M; Herndon, D N; Pollard, R B; Suzuki, F

1994-10-01

The protective effect of Kanzo-bushi-to (TJS-038) was investigated on the opportunistic infection of herpes simplex virus type 1 (HSV) in thermally injured mice (TI-Mice). We have previously reported that TI-Mice were approximately 100 times more susceptible to HSV infection than normal mice (N-Mice) and that CD8+ suppressor T (ST)-cells induced by burn injury were involved in causing this increased susceptibility of TI-Mice. Increased susceptibility of TI-Mice to the infection was reversed to the levels observed in N-Mice when TI-Mice were treated intraperitoneally with TJS-038 at a dose of 5 mg/kg 1 and 4 days after thermal injury. The activity of ST-cells was greatly decreased in TI-Mice treated with TJS-038. The generation of Vicia villosa lectin-adherent CD4+ CD28+ TCR-alpha/beta+ contrasuppressor T (Contra-ST)-cells associated with the appearance of ST-cells was expanded and occurred earlier in spleens of TJS-038-treated TI-Mice as compared with that of untreated TI-Mice. The improved resistance of TJS-038-treated TI-Mice to the infection was transferred to untreated TI-Mice by adoptive transfer of Contra-ST-cells prepared from TJS-038-treated TI-Mice. These results suggest that TJS-038 may restore the resistance of TI-Mice to the HSV infection through the expanded generation of Contra-ST-cells.

Transient inhibition and long-term facilitation of locomotion by phasic optogenetic activation of serotonin neurons

PubMed Central

Correia, Patrícia A; Lottem, Eran; Banerjee, Dhruba; Machado, Ana S; Carey, Megan R; Mainen, Zachary F

2017-01-01

Serotonin (5-HT) is associated with mood and motivation but the function of endogenous 5-HT remains controversial. Here, we studied the impact of phasic optogenetic activation of 5-HT neurons in mice over time scales from seconds to weeks. We found that activating dorsal raphe nucleus (DRN) 5-HT neurons induced a strong suppression of spontaneous locomotor behavior in the open field with rapid kinetics (onset ≤1 s). Inhibition of locomotion was independent of measures of anxiety or motor impairment and could be overcome by strong motivational drive. Repetitive place-contingent pairing of activation caused neither place preference nor aversion. However, repeated 15 min daily stimulation caused a persistent increase in spontaneous locomotion to emerge over three weeks. These results show that 5-HT transients have strong and opposing short and long-term effects on motor behavior that appear to arise from effects on the underlying factors that motivate actions. DOI: http://dx.doi.org/10.7554/eLife.20975.001 PMID:28193320

Rhubarb Tannins Extract Inhibits the Expression of Aquaporins 2 and 3 in Magnesium Sulphate-Induced Diarrhoea Model

PubMed Central

Liu, Chunfang; Zheng, Yanfang; Xu, Wen; Wang, Hui

2014-01-01

Tannins, a group of major active components of Chinese rhubarb and widely distributed in nature, have a significant antidiarrhoeal activity. Aquaporins (AQPs) 2 and 3 play important roles in regulating water transfer during diarrhoea. The present study aims to determine the effect of the total tannins extract of rhubarb on aquaporins (AQPs) 2 and 3 in diarrhoea mice and HT-29 cells both induced by magnesium sulphate (MgSO4). Our results showed that rhubarb tannins extract (RTE) significantly decreased the faecal water content in colon and evaluation index of defecation of diarrhoea mice. Interestingly, RTE could markedly reduce the mRNA and protein expression levels of AQPs 2 and 3 in apical and lateral mucosal epithelial cells in the colons of diarrhoea mice and HT-29 cells both induced by MgSO4 in a dose-dependent manner. Furthermore, RTE suppressed the production of cyclic monophosphate- (cAMP-) dependent protein kinase A catalytic subunits α (PKA C-α) and phosphorylated cAMP response element-binding protein (p-CREB, Ser133) in MgSO4-induced HT-29 cells. Our data showed for the first time that RTE inhibit AQPs 2 and 3 expression in vivo and in vitro via downregulating PKA/p-CREB signal pathway, which accounts for the antidiarrhoeal effect of RTE. PMID:25215286

Hydroxytyrosol prevents reduction in liver activity of Δ-5 and Δ-6 desaturases, oxidative stress, and depletion in long chain polyunsaturated fatty acid content in different tissues of high-fat diet fed mice.

PubMed

Valenzuela, Rodrigo; Echeverria, Francisca; Ortiz, Macarena; Rincón-Cervera, Miguel Ángel; Espinosa, Alejandra; Hernandez-Rodas, María Catalina; Illesca, Paola; Valenzuela, Alfonso; Videla, Luis A

2017-04-11

Eicosapentaenoic acid (EPA, C20:5n-3), docosahexaenoic acid (DHA, C22:6n-3) and arachidonic acid (AA, C20:4n-6) are long-chain polyunsaturated fatty acids (LCPUFAs) with relevant roles in the organism. EPA and DHA are synthesized from the precursor alpha-linolenic acid (ALA, C18:3n-3), whereas AA is produced from linoleic acid (LA, C18:2n-6) through the action of Δ5 and Δ6-desaturases. High-fat diet (HFD) decreases the activity of both desaturases and LCPUFA accretion in liver and other tissues. Hydroxytyrosol (HT), a natural antioxidant, has an important cytoprotective effects in different cells and tissues. Male mice C57BL/6 J were fed a control diet (CD) (10% fat, 20% protein, 70% carbohydrates) or a HFD (60% fat, 20% protein, 20% carbohydrates) for 12 weeks. Animals were daily supplemented with saline (CD) or 5 mg HT (HFD), and blood and the studied tissues were analyzed after the HT intervention. Parameters studied included liver histology (optical microscopy), activity of hepatic desaturases 5 and 6 (gas-liquid chromatography of methyl esters derivatives) and antioxidant enzymes (catalase, superoxide dismutase, glutathione peroxidase, and glutathione reductase by spectrophotometry), oxidative stress indicators (glutathione, thiobarbituric acid reactants, and the antioxidant capacity of plasma), gene expression assays for sterol regulatory element-binding protein 1c (SREBP-1c) (qPCR and ELISA), and LCPUFA profiles in liver, erythrocyte, brain, heart, and testicle (gas-liquid chromatography). HFD led to insulin resistance and liver steatosis associated with SREBP-1c upregulation, with enhancement in plasma and liver oxidative stress status and diminution in the synthesis and storage of n-6 and n-3 LCPUFAs in the studied tissues, compared to animals given control diet. HT supplementation significantly reduced fat accumulation in liver and plasma as well as tissue metabolic alterations induced by HFD. Furthermore, a normalization of desaturase activities, oxidative stress-related parameters, and tissue n-3 LCPUFA content was observed in HT-treated rats over control animals. HT supplementation prevents metabolic alterations in desaturase activities, oxidative stress status, and n-3 LCPUFA content in the liver and extrahepatic tissues of mice fed HFD.

Endogenous hypothermic response to hypoxia reduces brain injury: Implications for modeling hypoxic-ischemic encephalopathy and therapeutic hypothermia in neonatal mice.

PubMed

Reinboth, Barbara S; Köster, Christian; Abberger, Hanna; Prager, Sebastian; Bendix, Ivo; Felderhoff-Müser, Ursula; Herz, Josephine

2016-09-01

Hypothermia treatment (HT) is the only formally endorsed treatment recommended for hypoxic-ischemic encephalopathy (HIE). However, its success in protecting against brain injury is limited with a number to treat of 7-8. The identification of the target mechanisms of HIE in combination with HT will help to explain ineffective therapy outcomes but also requires stable experimental models in order to establish further neuroprotective therapies. Despite clinical and experimental indications for an endogenous thermoregulatory response to HIE, the potential effects on HIE-induced brain injury have largely been neglected in pre-clinical studies. In the present study we analyzed gray and white matter injury and neurobehavioral outcome in neonatal mice considering the endogenous thermoregulatory response during HIE combined with HT. HIE was induced in postnatal day (PND) 9 C57BL/6 mice through occlusion of the right common carotid artery followed by one hour of hypoxia. Hypoxia was performed at 8% or 10% oxygen (O2) at two different temperatures based on the nesting body core temperature. Using the model which mimics the clinical situation most closely, i.e. through maintenance of the nesting temperature during hypoxia we compared two mild HT protocols (rectal temperature difference 3°C for 4h), initiated either immediately after HIE or with delay of 2h. Injury was determined by histology, immunohistochemistry and western blot analyses at PND 16 and PND 51. Functional outcome was evaluated by Rota Rod, Elevated Plus Maze, Open Field and Novel Object Recognition testing at PND 30-PND 36 and PND 44-PND 50. We show that HIE modeling in neonatal mice is associated with a significant endogenous drop in body core temperature by 2°C resulting in profound neuroprotection, expressed by reduced neuropathological injury scores, reduced loss of neurons, axonal structures, myelin and decreased astrogliosis. Immediately applied post-hypoxic HT revealed slight advantages over a delayed onset of therapy on short- and long-term histological outcome demonstrated by reduced neuropathological injury scores and preservation of hippocampal structures. However, depending on the brain region analyzed neuroprotective effects were similar or even reduced compared to protection by endogenous cooling during HIE modeling. Moreover, long-term neurobehavioral outcome was only partially improved for motoric function (i.e. Rota Rod performance and rearing activity) while cognitive deficits (i.e. novel object recognition) remained unchanged. These findings emphasize the need to maintain the nesting temperature during the initiation of the pathological insult and highlight the urgency to develop and assess new adjuvant therapies for HT in well-defined experimental models. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Distinct Neurobehavioural Effects of Cannabidiol in Transmembrane Domain Neuregulin 1 Mutant Mice

PubMed Central

Long, Leonora E.; Chesworth, Rose; Huang, Xu-Feng; Wong, Alexander; Spiro, Adena; McGregor, Iain S.; Arnold, Jonathon C.; Karl, Tim

2012-01-01

The cannabis constituent cannabidiol (CBD) possesses anxiolytic and antipsychotic properties. We have previously shown that transmembrane domain neuregulin 1 mutant (Nrg1 TM HET) mice display altered neurobehavioural responses to the main psychoactive constituent of cannabis, Δ9-tetrahydrocannabinol. Here we investigated whether Nrg1 TM HET mice respond differently to CBD and whether CBD reverses schizophrenia-related phenotypes expressed by these mice. Adult male Nrg1 TM HET and wild type-like littermates (WT) received vehicle or CBD (1, 50 or 100 mg/kg i.p.) for 21 days. During treatment and 48 h after withdrawal we measured behaviour, whole blood CBD concentrations and autoradiographic receptor binding. Nrg1 HET mice displayed locomotor hyperactivity, PPI deficits and reduced 5-HT2A receptor binding density in the substantia nigra, but these phenotypes were not reversed by CBD. However, long-term CBD (50 and 100 mg/kg) selectively enhanced social interaction in Nrg1 TM HET mice. Furthermore, acute CBD (100 mg/kg) selectively increased PPI in Nrg1 TM HET mice, although tolerance to this effect was manifest upon repeated CBD administration. Long-term CBD (50 mg/kg) also selectively increased GABAA receptor binding in the granular retrosplenial cortex in Nrg1 TM HET mice and reduced 5-HT2A binding in the substantia nigra in WT mice. Nrg1 appears necessary for CBD-induced anxiolysis since only WT mice developed decreased anxiety-related behaviour with repeated CBD treatment. Altered pharmacokinetics in mutant mice could not explain our findings since no genotype differences existed in CBD blood concentrations. Here we demonstrate that Nrg1 modulates acute and long-term neurobehavioural effects of CBD, which does not reverse the schizophrenia-relevant phenotypes. PMID:22509273

Distinct neurobehavioural effects of cannabidiol in transmembrane domain neuregulin 1 mutant mice.

PubMed

Long, Leonora E; Chesworth, Rose; Huang, Xu-Feng; Wong, Alexander; Spiro, Adena; McGregor, Iain S; Arnold, Jonathon C; Karl, Tim

2012-01-01

The cannabis constituent cannabidiol (CBD) possesses anxiolytic and antipsychotic properties. We have previously shown that transmembrane domain neuregulin 1 mutant (Nrg1 TM HET) mice display altered neurobehavioural responses to the main psychoactive constituent of cannabis, Δ(9)-tetrahydrocannabinol. Here we investigated whether Nrg1 TM HET mice respond differently to CBD and whether CBD reverses schizophrenia-related phenotypes expressed by these mice. Adult male Nrg1 TM HET and wild type-like littermates (WT) received vehicle or CBD (1, 50 or 100 mg/kg i.p.) for 21 days. During treatment and 48 h after withdrawal we measured behaviour, whole blood CBD concentrations and autoradiographic receptor binding. Nrg1 HET mice displayed locomotor hyperactivity, PPI deficits and reduced 5-HT(2A) receptor binding density in the substantia nigra, but these phenotypes were not reversed by CBD. However, long-term CBD (50 and 100 mg/kg) selectively enhanced social interaction in Nrg1 TM HET mice. Furthermore, acute CBD (100 mg/kg) selectively increased PPI in Nrg1 TM HET mice, although tolerance to this effect was manifest upon repeated CBD administration. Long-term CBD (50 mg/kg) also selectively increased GABA(A) receptor binding in the granular retrosplenial cortex in Nrg1 TM HET mice and reduced 5-HT(2A) binding in the substantia nigra in WT mice. Nrg1 appears necessary for CBD-induced anxiolysis since only WT mice developed decreased anxiety-related behaviour with repeated CBD treatment. Altered pharmacokinetics in mutant mice could not explain our findings since no genotype differences existed in CBD blood concentrations. Here we demonstrate that Nrg1 modulates acute and long-term neurobehavioural effects of CBD, which does not reverse the schizophrenia-relevant phenotypes.

Activation of Ventral Tegmental Area 5-HT2C Receptors Reduces Incentive Motivation.

PubMed

Valencia-Torres, Lourdes; Olarte-Sánchez, Cristian M; Lyons, David J; Georgescu, Teodora; Greenwald-Yarnell, Megan; Myers, Martin G; Bradshaw, Christopher M; Heisler, Lora K

2017-06-01

Obesity is primarily due to food intake in excess of the body's energetic requirements, intake that is not only associated with hunger but also the incentive value of food. The 5-hydroxytryptamine 2C receptor (5-HT 2C R) is a target for the treatment of human obesity. Mechanistically, 5-HT 2C Rs are positioned to influence both homeostatic feeding circuits within the hypothalamus and reward circuits within the ventral tegmental area (VTA). Here we investigated the role of 5-HT 2C Rs in incentive motivation using a mathematical model of progressive ratio (PR) responding in mice. We found that the 5-HT 2C R agonist lorcaserin significantly reduced both ad libitum chow intake and PR responding for chocolate pellets and increased c-fos expression in VTA 5-HT 2C R expressing γ-aminobutyric acid (GABA) neurons, but not 5-HT 2C R expressing dopamine (DA) neurons. We next adopted a chemogenetic approach using a 5-HT 2C R CRE line to clarify the function of subset of 5-HT 2C receptor expressing VTA neurons in the modulation of appetite and food-motivated behavior. Activation of VTA 5-HT 2C receptor expressing neurons significantly reduced ad libitum chow intake, operant responding for chocolate pellets, and the incentive value of food. In contrast, chemogenetic inhibition of VTA 5-HT 2C receptor expressing neurons had no effect on the feeding behavior. These results indicate that activation of the subpopulation of 5-HT 2C R neurons within the VTA is sufficient to significantly reduce homeostatic feeding and effort-based intake of palatable food, and that this subset has an inhibitory role in motivational processes. These findings are relevant to the treatment of obesity.

Activation of Ventral Tegmental Area 5-HT2C Receptors Reduces Incentive Motivation

PubMed Central

Valencia-Torres, Lourdes; Olarte-Sánchez, Cristian M; Lyons, David J; Georgescu, Teodora; Greenwald-Yarnell, Megan; Myers, Martin G; Bradshaw, Christopher M; Heisler, Lora K

2017-01-01

Obesity is primarily due to food intake in excess of the body's energetic requirements, intake that is not only associated with hunger but also the incentive value of food. The 5-hydroxytryptamine 2C receptor (5-HT2CR) is a target for the treatment of human obesity. Mechanistically, 5-HT2CRs are positioned to influence both homeostatic feeding circuits within the hypothalamus and reward circuits within the ventral tegmental area (VTA). Here we investigated the role of 5-HT2CRs in incentive motivation using a mathematical model of progressive ratio (PR) responding in mice. We found that the 5-HT2CR agonist lorcaserin significantly reduced both ad libitum chow intake and PR responding for chocolate pellets and increased c-fos expression in VTA 5-HT2CR expressing γ-aminobutyric acid (GABA) neurons, but not 5-HT2CR expressing dopamine (DA) neurons. We next adopted a chemogenetic approach using a 5-HT2CRCRE line to clarify the function of subset of 5-HT2C receptor expressing VTA neurons in the modulation of appetite and food-motivated behavior. Activation of VTA 5-HT2C receptor expressing neurons significantly reduced ad libitum chow intake, operant responding for chocolate pellets, and the incentive value of food. In contrast, chemogenetic inhibition of VTA 5-HT2C receptor expressing neurons had no effect on the feeding behavior. These results indicate that activation of the subpopulation of 5-HT2CR neurons within the VTA is sufficient to significantly reduce homeostatic feeding and effort-based intake of palatable food, and that this subset has an inhibitory role in motivational processes. These findings are relevant to the treatment of obesity. PMID:27882999

The acute and long-term neurotoxic effects of MDMA on marble burying behaviour in mice.

PubMed

Saadat, Kathryn S; Elliott, J Martin; Colado, M Isabel; Green, A Richard

2006-03-01

When mice are exposed to harmless objects such as marbles in their cage they bury them, a behaviour sometimes known as defensive burying. We investigated the effect of an acute dose of MDMA (èecstasy') and other psychoactive drugs on marble burying and also examined the effect of a prior neurotoxic dose of MDMA or p-chloroamphetamine (PCA) on burying. Acute administration of MDMA produced dose-dependent inhibition of marble burying (EC50: 7.6 micro mol/kg). Other drugs that enhance monoamine function also produced dose-dependent inhibition: methamphetamine PCA paroxetine MDMA GBR 12909 methylphenidate. None of these drugs altered locomotor activity at a dose that inhibited burying. A prior neurotoxic dose of MDMA, which decreased striatal dopamine content by 60%, but left striatal 5-HT content unaltered, did not alter spontaneous marble burying 18 or 40 days later. However, a neurotoxic dose of PCA which decreased striatal dopamine by 60% and striatal 5-HT by 70% attenuated marble burying 28 days later. Overall, these data suggest that MDMA, primarily by acutely increasing 5-HT function, acts like several anxiolytic drugs in this behavioural model. Long-term loss of cerebral 5-HT content also produced a similar effect. Since this change was observed only after 28 days, it is probably due to an adaptive response in the brain.

Amelioration of Atherosclerosis by the New Medicinal Mushroom Grifola gargal Singer

PubMed Central

Harada, Etsuko; D'Alessandro-Gabazza, Corina N.; Toda, Masaaki; Morizono, Toshihiro; Chelakkot-Govindalayathil, Ayshwarya-Lakshmi; Roeen, Ziaurahman; Urawa, Masahito; Yasuma, Taro; Yano, Yutaka; Sumiya, Toshimitsu

2015-01-01

ABSTRACT The beneficial effects of edible mushrooms for improving chronic intractable diseases have been documented. However, the antiatherogenic activity of the new medicinal mushroom Grifola gargal is unknown. Therefore, we evaluated whether Grifola gargal can prevent or delay the progression of atherosclerosis. Atherosclerosis was induced in ApoE lipoprotein-deficient mice by subcutaneous infusion of angiotensin II. Grifola gargal extract (GGE) was prepared and intraperitoneally injected. The weight of heart and vessels, dilatation/atheroma formation of thoracic and abdominal aorta, the percentage of peripheral granulocytes, and the blood concentration of MCP-1/CCL2 were significantly reduced in mice treated with GGE compared to untreated mice. By contrast, the percentage of regulatory T cells and the plasma concentration of SDF-1/CXCL12 were significantly increased in mice treated with the mushroom extract compared to untreated mice. In vitro, GGE significantly increased the secretion of SDF-1/CXCL12, VEGF, and TGF-β1 from fibroblasts compared to control. This study demonstrated for the first time that Grifola gargal therapy can enhance regulatory T cells and ameliorate atherosclerosis in mice. PMID:25799023

Treating fat grafts with human endothelial progenitor cells promotes their vascularization and improves their survival in diabetes mellitus.

PubMed

Hamed, Saher; Ben-Nun, Ohad; Egozi, Dana; Keren, Aviad; Malyarova, Nastya; Kruchevsky, Danny; Gilhar, Amos; Ullmann, Yehuda

2012-10-01

Bone marrow-derived endothelial progenitor cells are required for vascularization of a fat graft to form a functional microvasculature within the graft and to facilitate its integration into the surrounding tissues. Organ transplantation carries a high risk of graft loss and rejection in patients with diabetes mellitus because endothelial progenitor cell function is impaired. The authors investigated the influence of endothelial progenitor cell treatment on the phenotype and survival of human fat grafts in immunocompromised mice with experimentally induced diabetes mellitus. The authors injected 1 ml of human fat tissue into the scalps of 14 nondiabetic and 28 diabetic immunocompromised mice, and then treated some of the grafts with endothelial progenitor cells that was isolated from the blood of a human donor. The phenotype of the endothelial progenitor cell-treated fat grafts from the 14 diabetic mice was compared with that of the untreated fat grafts from 14 nondiabetic and 14 diabetic mice, 18 days and 15 weeks after fat transplantation. Determination of graft phenotype included measurements of weight and volume, vascular endothelial growth factor levels, vascular endothelial growth factor receptor-2, endothelial nitric oxide synthase, and caspase 3 expression levels, and histologic analysis of the extent of vascularization. The untreated grafts from the diabetic mice were fully resorbed 15 weeks after fat transplantation. The phenotype of endothelial progenitor cell-treated fat grafts from the diabetic mice was similar to that of the untreated fat grafts from the nondiabetic mice. Endothelial progenitor cell treatment of transplanted fat can increase the survival of a fat graft by inducing its vascularization and decreasing the extent of apoptosis.

Orally administered sodium 4-phenylbutyrate suppresses the development of dextran sulfate sodium-induced colitis in mice.

PubMed

Ono, Kazuhiko; Nimura, Satoshi; Hideshima, Yuko; Nabeshima, Kazuki; Nakashima, Manabu

2017-12-01

Sodium 4-phenylbutyrate (PBA) exerts therapeutic effects in a wide range of pathologies. A previous study by the present authors revealed that intraperitoneal administration of PBA suppresses the onset of dextran sulfate sodium (DSS)-induced colitis in mice. In the present study, the effects of orally administered PBA are investigated, as this route of administration is more clinically relevant. The therapeutic efficacy of PBA (10 mg/12 h) in mice with experimental colitis was assessed based on the disease activity index, production of inflammatory cytokines, colon length and histopathological investigations. The results of the present study demonstrated a significantly higher survival rate in the PBA-treated group compared with the PBA-untreated (DSS control) group (P=0.0156). PBA treatment improved pathological indices of experimental colitis (P<0.05). Furthermore, the oral administration of PBA significantly inhibited the DSS-induced shortening of the colon (P<0.05) and overproduction of interleukin (IL)-1β and IL-6 (both P<0.05) as measured in colonic lavage fluids. A marked attenuation of the DSS-induced overproduction of tumor necrosis factor was also observed. For histopathological analysis, a marked decrease in mature goblet cells and increase in enlarged nuclei of the absorptive cells was observed in colon lesions of DSS control mice as compared with normal untreated mice. However, in the PBA-treated mice, no such lesions were observed and the mucosa resembled that of DSS-untreated mice. The results of the present study, combined with those results of a previous study, suggest that oral and intraperitoneal administration of PBA have similar preventative effects on DSS-induced colitis, achieved by suppressing its pathogenesis.

Effects of LSD on grooming behavior in serotonin transporter heterozygous (Sert⁺/⁻) mice.

PubMed

Kyzar, Evan J; Stewart, Adam Michael; Kalueff, Allan V

2016-01-01

Serotonin (5-HT) plays a crucial role in the brain, modulating mood, cognition and reward. The serotonin transporter (SERT) is responsible for the reuptake of 5-HT from the synaptic cleft and regulates serotonin signaling in the brain. In humans, SERT genetic variance is linked to the pathogenesis of various psychiatric disorders, including anxiety, autism spectrum disorders (ASD) and obsessive-compulsive disorder (OCD). Rodent self-grooming is a complex, evolutionarily conserved patterned behavior relevant to stress, ASD and OCD. Genetic ablation of mouse Sert causes various behavioral deficits, including increased anxiety and grooming behavior. The hallucinogenic drug lysergic acid diethylamide (LSD) is a potent serotonergic agonist known to modulate human and animal behavior. Here, we examined heterozygous Sert(+/-) mouse behavior following acute administration of LSD (0.32 mg/kg). Overall, Sert(+/-) mice displayed a longer duration of self-grooming behavior regardless of LSD treatment. In contrast, LSD increased serotonin-sensitive behaviors, such as head twitching, tremors and backwards gait behaviors in both Sert(+/+) and Sert(+/-) mice. There were no significant interactions between LSD treatment and Sert gene dosage in any of the behavioral domains measured. These results suggest that Sert(+/-) mice may respond to the behavioral effects of LSD in a similar manner to wild-type mice. Copyright © 2015 Elsevier B.V. All rights reserved.

Molecular role of TGF-beta, secreted from a new type of CD4+ suppressor T cell, NY4.2, in the prevention of autoimmune IDDM in NOD mice.

PubMed

Han, H S; Jun, H S; Utsugi, T; Yoon, J W

1997-06-01

A new type of CD4+ T cell clone (NY4.2) isolated from pancreatic islet-infiltrated lymphocytes of acutely diabetic non-obese diabetic (NOD) mice prevents the development of insulin-dependent diabetes mellitus (IDDM) in NOD mice, as well as the recurrence of autoimmune diabetes in syngeneic islet-transplanted NOD mice. It has been demonstrated that the cytokine TGF-beta, secreted from the cells of this clone, is the substance which prevents autoimmune IDDM. This investigation was initiated to determine the molecular role TGF-beta plays in the prevention of autoimmune IDDM by determining its effect on IL-2-induced signal transduction in Con A-activated NOD mouse splenocytes and HT-2 cells. First, we determined whether TGF-beta, secreted from NY4.2 T cells, inhibits IL-2-dependent T cell proliferation in HT-2 cells (IL-2-dependent T cell line) and NOD splenocytes. We found that TGF-beta suppresses IL-2-dependent T cell proliferation. Second, we determined whether TGF-beta inhibits the activation of Janus kinases (JAKs), as well as signal transducers and activators of transcription (STAT) proteins, involved in an IL-2-induced signalling pathway that normally leads to the proliferation of T cells. We found that TGF-beta inhibited tyrosine phosphorylation of JAK1, JAK3, STAT3 and STAT5 in Con A blasts from NOD splenocytes and HT-2 cells. Third, we examined whether TGF-beta inhibits the cooperation between STAT proteins and mitogen-activated protein kinase (MAPK), especially extracellular signal-regulated kinase 2 (ERK2). We found that TGF-beta inhibited the association of STAT3 and STAT5 with ERK2 in Con A blasts from NOD splenocytes and HT-2 cells. On the basis of these observations, we conclude that TGF-beta may interfere with signal transduction via inhibition of the IL-2-induced JAK/STAT pathway and inhibition of the association of STAT proteins with ERK2 in T cells from NOD splenocytes, resulting in the inhibition of IL-2-dependent T cell proliferation. TGF-beta-mediated suppression of T cell activation may be responsible for the prevention of effector T cell-mediated autoimmune IDDM in NOD mice by TGF-beta-producing CD4+ suppressor T cells.

Structural modifications of N-(1,2,3,4-tetrahydronaphthalen-1-yl)-4-aryl-1-piperazinehexanamides: influence on lipophilicity and 5-HT7 receptor activity. Part III.

PubMed

Leopoldo, Marcello; Lacivita, Enza; De Giorgio, Paola; Fracasso, Claudia; Guzzetti, Sara; Caccia, Silvio; Contino, Marialessandra; Colabufo, Nicola A; Berardi, Francesco; Perrone, Roberto

2008-09-25

Starting from the previously reported 5-HT 7 receptor agents 4-7 with N-(1,2,3,4-tetrahydronaphthalen-1-yl)-4-aryl-1-piperazinehexanamide structure, the 1-(2-methylthiophenyl)-, 1-(2-diphenyl)-, 1-(2-isopropylphenyl)-, and 1-(2-methoxyphenyl)piperazine derivatives 8-31 were designed with the primary aim to obtain new compounds endowed with suitable physicochemical properties for rapid and extensive penetration into the brain. The affinities for 5-HT 7, 5-HT 1A, and D 2 receptors of compounds 8-31 were assessed, and several compounds displayed 5-HT 7 receptor affinities in the nanomolar range. Among these, N-(4-cyanophenylmethyl)-4-(2-diphenyl)-1-piperazinehexanamide (25) showed high 5-HT 7 receptor affinity (Ki = 0.58 nM), high selectivity over 5-HT 1A and D 2 receptors (324- and 245-fold, respectively), and agonist properties (maximal effect = 82%, EC 50 = 0.60 microM). After intraperitoneal injection in mice, 25 rapidly reached the systemic circulation and entered the brain. Its brain concentration-time profile paralleled that in plasma, indicating that 25 rapidly and freely distributes across the blood-brain barrier. Compound 25 underwent N-dealkylation to the corresponding 1-arylpiperazine metabolite.

Altered entrainment to the day/night cycle attenuates the daily rise in circulating corticosterone in the mouse.

PubMed

Sollars, Patricia J; Weiser, Michael J; Kudwa, Andrea E; Bramley, Jayne R; Ogilvie, Malcolm D; Spencer, Robert L; Handa, Robert J; Pickard, Gary E

2014-01-01

The suprachiasmatic nucleus (SCN) is a circadian oscillator entrained to the day/night cycle via input from the retina. Serotonin (5-HT) afferents to the SCN modulate retinal signals via activation of 5-HT1B receptors, decreasing responsiveness to light. Consequently, 5-HT1B receptor knockout (KO) mice entrain to the day/night cycle with delayed activity onsets. Since circulating corticosterone levels exhibit a robust daily rhythm peaking around activity onset, we asked whether delayed entrainment of activity onsets affects rhythmic corticosterone secretion. Wheel-running activity and plasma corticosterone were monitored in mice housed under several different lighting regimens. Both duration of the light:dark cycle (T cycle) and the duration of light within that cycle was altered. 5-HT1B KO mice that entrained to a 9.5L:13.5D (short day in a T = 23 h) cycle with activity onsets delayed more than 4 h after light offset exhibited a corticosterone rhythm in phase with activity rhythms but reduced 50% in amplitude compared to animals that initiated daily activity <4 h after light offset. Wild type mice in 8L:14D (short day in a T = 22 h) conditions with highly delayed activity onsets also exhibited a 50% reduction in peak plasma corticosterone levels. Exogenous adrenocorticotropin (ACTH) stimulation in animals exhibiting highly delayed entrainment suggested that the endogenous rhythm of adrenal responsiveness to ACTH remained aligned with SCN-driven behavioral activity. Circadian clock gene expression in the adrenal cortex of these same animals suggested that the adrenal circadian clock was also aligned with SCN-driven behavior. Under T cycles <24 h, altered circadian entrainment to short day (winter-like) conditions, manifest as long delays in activity onset after light offset, severely reduces the amplitude of the diurnal rhythm of plasma corticosterone. Such a pronounced reduction in the glucocorticoid rhythm may alter rhythmic gene expression in the central nervous system and in peripheral organs contributing to an array of potential pathophysiologies.

Altered Entrainment to the Day/Night Cycle Attenuates the Daily Rise in Circulating Corticosterone in the Mouse

PubMed Central

Sollars, Patricia J.; Weiser, Michael J.; Kudwa, Andrea E.; Bramley, Jayne R.; Ogilvie, Malcolm D.; Spencer, Robert L.; Handa, Robert J.; Pickard, Gary E.

2014-01-01

The suprachiasmatic nucleus (SCN) is a circadian oscillator entrained to the day/night cycle via input from the retina. Serotonin (5-HT) afferents to the SCN modulate retinal signals via activation of 5-HT1B receptors, decreasing responsiveness to light. Consequently, 5-HT1B receptor knockout (KO) mice entrain to the day/night cycle with delayed activity onsets. Since circulating corticosterone levels exhibit a robust daily rhythm peaking around activity onset, we asked whether delayed entrainment of activity onsets affects rhythmic corticosterone secretion. Wheel-running activity and plasma corticosterone were monitored in mice housed under several different lighting regimens. Both duration of the light∶dark cycle (T cycle) and the duration of light within that cycle was altered. 5-HT1B KO mice that entrained to a 9.5L:13.5D (short day in a T = 23 h) cycle with activity onsets delayed more than 4 h after light offset exhibited a corticosterone rhythm in phase with activity rhythms but reduced 50% in amplitude compared to animals that initiated daily activity <4 h after light offset. Wild type mice in 8L:14D (short day in a T = 22 h) conditions with highly delayed activity onsets also exhibited a 50% reduction in peak plasma corticosterone levels. Exogenous adrenocorticotropin (ACTH) stimulation in animals exhibiting highly delayed entrainment suggested that the endogenous rhythm of adrenal responsiveness to ACTH remained aligned with SCN-driven behavioral activity. Circadian clock gene expression in the adrenal cortex of these same animals suggested that the adrenal circadian clock was also aligned with SCN-driven behavior. Under T cycles <24 h, altered circadian entrainment to short day (winter-like) conditions, manifest as long delays in activity onset after light offset, severely reduces the amplitude of the diurnal rhythm of plasma corticosterone. Such a pronounced reduction in the glucocorticoid rhythm may alter rhythmic gene expression in the central nervous system and in peripheral organs contributing to an array of potential pathophysiologies. PMID:25365210

The Antidepressant 5-HT2A Receptor Antagonists Pizotifen and Cyproheptadine Inhibit Serotonin-Enhanced Platelet Function

PubMed Central

Lin, Olivia A.; Karim, Zubair A.; Vemana, Hari Priya; Espinosa, Enma V. P.; Khasawneh, Fadi T.

2014-01-01

There is considerable interest in defining new agents or targets for antithrombotic purposes. The 5-HT2A receptor is a G-protein coupled receptor (GPCR) expressed on many cell types, and a known therapeutic target for many disease states. This serotonin receptor is also known to regulate platelet function. Thus, in our FDA-approved drug repurposing efforts, we investigated the antiplatelet activity of cyproheptadine and pizotifen, two antidepressant 5-HT2A Receptor antagonists. Our results revealed that cyproheptadine and pizotifen reversed serotonin-enhanced ADP-induced platelet aggregation in vitro and ex vivo. And the inhibitory effects of these two agents were found to be similar to that of EMD 281014, a 5-HT2A Receptor antagonist under development. In separate experiments, our studies revealed that these 5-HT2A receptor antagonists have the capacity to reduce serotonin-enhanced ADP-induced elevation in intracellular calcium levels and tyrosine phosphorylation. Using flow cytometry, we also observed that cyproheptadine, pizotifen, and EMD 281014 inhibited serotonin-enhanced ADP-induced phosphatidylserine (PS) exposure, P-selectin expression, and glycoprotein IIb-IIIa activation. Furthermore, using a carotid artery thrombosis model, these agents prolonged the time for thrombotic occlusion in mice in vivo. Finally, the tail-bleeding time was investigated to assess the effect of cyproheptadine and pizotifen on hemostasis. Our findings indicated prolonged bleeding time in both cyproheptadine- and pizotifen-treated mice. Notably, the increases in occlusion and bleeding times associated with these two agents were comparable to that of EMD 281014, and to clopidogrel, a commonly used antiplatelet drug, again, in a fashion comparable to clopidogrel and EMD 281014. Collectively, our data indicate that the antidepressant 5-HT2A antagonists, cyproheptadine and pizotifen do exert antiplatelet and thromboprotective effects, but similar to clopidogrel and EMD 281014, their use may interfere with normal hemostasis. PMID:24466319

Modification of 5-methoxy-N,N-dimethyltryptamine-induced hyperactivity by monoamine oxidase A inhibitor harmaline in mice and the underlying serotonergic mechanisms.

PubMed

Jiang, Xi-Ling; Shen, Hong-Wu; Yu, Ai-Ming

2016-06-01

5-Methoxy-N,N-dimethyltryptamine (5-MeO-DMT) and harmaline are indolealkylamine (IAA) drugs often abused together. Our recent studies have revealed the significant effects of co-administered harmaline, a monoamine oxidase inhibitor (MAOI), on 5-MeO-DMT pharmacokinetics and thermoregulation. This study was to delineate the impact of harmaline and 5-MeO-DMT on home-cage activity in mouse models, as well as the contribution of serotonin (5-HT) receptors. Home-cage activities of individual animals were monitored automatically in the home cages following implantation of telemetry transmitters and administration of various doses of IAA drugs and 5-HT receptor antagonists. Area under the effect curve (AUEC) of mouse activity values were calculated by trapezoidal rule. High dose of harmaline (15mg/kg, ip) alone caused an early-phase (0-45min) hypoactivity in mice that was fully attenuated by 5-HT1A receptor antagonist WAY-100635, whereas a late-phase (45-180min) hyperactivity that was reduced by 5-HT2A receptor antagonist MDL-100907. 5-MeO-DMT (10 and 20mg/kg, ip) alone induced biphasic effects, an early-phase (0-45min) hypoactivity that was completely attenuated by WAY-100635, and a late-phase (45-180min) hyperactivity that was fully suppressed by MDL-100907. Interestingly, co-administration of MAOI harmaline (2-15mg/kg) with a subthreshold dose of 5-MeO-DMT (2mg/kg) induced excessive hyperactivities at late phase (45-180min) that could be abolished by either WAY-100635 or MDL-100907. Co-administration of MAOI with 5-MeO-DMT provokes excessive late-phase hyperactivity, which involves the activation of both 5-HT1A and 5-HT2A receptors. Copyright © 2016 Institute of Pharmacology, Polish Academy of Sciences. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.

Role of maternal 5-HT(1A) receptor in programming offspring emotional and physical development.

PubMed

van Velzen, A; Toth, M

2010-11-01

Serotonin(1A) receptor (5-HT(1A)R) deficiency has been associated with anxiety and depression and mice with genetic receptor inactivation exhibit heightened anxiety. We have reported that 5-HT(1A)R is not only a genetic but also a maternal 'environmental' factor in the development of anxiety in Swiss-Webster mice. Here, we tested whether the emergence of maternal genotype-dependent adult anxiety is preceded by early behavioral abnormalities or whether it is manifested following a normal emotional development. Pups born to null or heterozygote mothers had significantly reduced ultrasonic vocalization (USV) between postnatal day (P) 4 and 12, indicating an influence of the maternal genotype. The offspring's own genotype had an effect limited to P4. Furthermore, we observed reduced weight gain in the null offspring of null but not heterozygote mothers, indicating that a complete maternal receptor deficiency compromises physical development of the offspring. Except a short perinatal deficit during the dark period, heterozygote females displayed normal maternal behavior, which, with the early appearance of USV deficit, suggests a role for 5-HT(1A)R during pre-/perinatal development. Consistent with this notion, adult anxiety in the offspring is determined during the pre-/perinatal period. In contrast to heterozygote females, null mothers exhibited impaired pup retrieval and nest building that may explain the reduced weight gain of their offspring. Taken together, our data indicate an important role for the maternal 5-HT(1A)R in regulating emotional and physical development of their offspring. Because reduced receptor binding has been reported in depression, including postpartum depression, reduced 5-HT(1A)R function in mothers may influence the emotional development of their offspring. © 2010 The Authors. Genes, Brain and Behavior © 2010 Blackwell Publishing Ltd and International Behavioural and Neural Genetics Society.

Modification of 5-methoxy-N,N-dimethyltryptamine-induced hyperactivity by monoamine oxidase A inhibitor harmaline in mice and the underlying serotonergic mechanisms

PubMed Central

Jiang, Xi-Ling; Shen, Hong-Wu; Yu, Ai-Ming

2016-01-01

Background 5-Methoxy-N,N-dimethyltryptamine (5-MeO-DMT) and harmaline are indolealkylamine (IAA) drugs often abused together. Our recent studies have revealed the significant effects of co-administered harmaline, a monoamine oxidase inhibitor (MAOI), on 5-MeO-DMT pharmacokinetics and thermoregulation. This study was to delineate the impact of harmaline and 5-MeO-DMT on home-cage activity in mouse models, as well as the contribution of serotonin (5-HT) receptors. Methods Home-cage activities of individual animals were monitored automatically in the home cages following implantation of telemetry transmitters and administration of various doses of IAA drugs and 5-HT receptor antagonists. Area under the effect curve (AUEC) of mouse activity values were calculated by trapezoidal rule. Results High dose of harmaline (15 mg/kg, ip) alone caused an early-phase (0–45 min) hypoactivity in mice that was fully attenuated by 5-HT1A receptor antagonist WAY-100635, whereas a late-phase (45–180 min) hyperactivity that was reduced by 5-HT2A receptor antagonist MDL-100907. 5-MeO-DMT (10 and 20 mg/kg, ip) alone induced biphasic effects, an early-phase (0–45 min) hypoactivity that was completely attenuated by WAY-100635, and a late-phase (45–180 min) hyperactivity that was fully suppressed by MDL-100907. Interestingly, co-administration of MAOI harmaline (2–15 mg/kg) with a subthreshold dose of 5-MeO-DMT (2 mg/kg) induced excessive hyperactivities at late phase (45–180 min) that could be abolished by either WAY-100635 or MDL-100907. Conclusions Co-administration of MAOI with 5-MeO-DMT provokes excessive late-phase hyperactivity, which involves the activation of both 5-HT1A and 5-HT2A receptors. PMID:26977821

Ebselen has lithium-like effects on central 5-HT2A receptor function.

PubMed

Antoniadou, I; Kouskou, M; Arsiwala, T; Singh, N; Vasudevan, S R; Fowler, T; Cadirci, E; Churchill, G C; Sharp, T

2018-02-27

Lithium's antidepressant action may be mediated by inhibition of inositol monophosphatase (IMPase), a key enzyme in G q protein coupled receptor signalling. Recently, the antioxidant agent ebselen was identified as an IMPase inhibitor. Here we investigated both ebselen and lithium in models of the 5-HT 2A receptor, a G q protein coupled receptor implicated in lithium's actions. 5-HT 2A receptor function was modelled in mice by measuring the behavioural (head-twitches) and cortical immediate early gene (IEG; Arc, c-fos and Erg2 mRNA) responses to 5-HT 2A receptor agonist administration. Ebselen and lithium were administered either acutely or chronically prior to assessment of 5-HT 2A receptor function. Given the SSRI augmenting action of lithium and 5-HT 2A antagonists, ebselen was also tested for this action by co-administration with the SSRI citalopram in microdialysis (extracellular 5-HT) experiments. Acute and repeated administration of ebselen inhibited behavioural and IEG responses to the 5-HT 2A receptor agonist DOI. Repeated lithium also inhibited DOI-evoked behavioural and IEG responses. In comparison, a selective IMPase inhibitor (L-690,330) attenuated the behavioural response to DOI whereas glycogen synthase kinase inhibitor (AR-A014418) did not. Finally, ebselen increased regional brain 5-HT synthesis and enhanced the increase in extracellular 5-HT induced by citalopram. The current data demonstrate lithium-mimetic effects of ebselen in different experimental models of 5-HT 2A receptor function, likely mediated by IMPase inhibition. This evidence of lithium-like neuropharmacological effects of ebselen adds further support for the clinical testing of ebselen in mood disorder, including as an antidepressant augmenting agent. This article is protected by copyright. All rights reserved.

Evidence for involvement of protein kinases in the regulation of serotonin synthesis and turnover in the mouse brain in vivo.

PubMed

Stenfors, C; Ross, S B

2002-11-01

Inhibition of cAMP-dependent protein kinase (PKA) with N-[2-methylamino)ethyl]-5-isoquinolinesulfonamide (H-8) almost completely antagonized the increase in 5-HTP accumulation and 5-HIAA/5-HT ratio in hypothalamus induced by NAS-181, a 5-HT(1B) receptor antagonist, but had no effect when the mice were treated with NAS-181 together with WAY-100,635, a selective 5-HT(1A) receptor antagonist. Inhibition of Ca(2+)-calmodulin-dependent protein kinase (CaM kinase II) with the calmodulin antagonist N-(4-aminobutyl)-5-chloro-2-naphtalenesulfonamide (W-13) did not antagonise the effect of NAS-181 alone, but counteracted that evoked by the combined treatment with NAS-181 and WAY-100,635. The results indicate that activation of tryptophan hydroxylase by reducing the tone from terminal 5-HT(1B) receptors involves PKA whereas the depolarisation-induced activation of tryptophan hydroxylase involves CaM kinase II. The increase in the 5-HIAA/5-HT ratio may under the experimental conditions used suggest CaM kinase II-induced phosphorylation of synapsin I resulting in increased 5-HT release.

Phase-delay in the light-dark cycle impairs clock gene expression and levels of serotonin, norepinephrine, and their metabolites in the mouse hippocampus and amygdala.

PubMed

Moriya, Shunpei; Tahara, Yu; Sasaki, Hiroyuki; Ishigooka, Jun; Shibata, Shigenobu

2015-11-01

A number of animal studies have implicated circadian clock genes in the regulation of mood, anxiety, and reward. However, the effect of misalignment of the environmental light-dark and internal circadian clock on the monoamine system is not fully understood. In the present study, we examined whether an abnormal light-dark schedule would affect behavior-, circadian clock-, and monoamine-related gene expressions, along with monoamine contents in the amygdala and hippocampus of mice. Mice were subjected to an 8-hour phase delay in the light-dark cycle (Shift) every two days for four weeks, and locomotor activity was continuously measured. We examined the circadian expression of clock genes (Per1, Per2, and Bmal1) and genes of the NE/5HT uptake transporters (Net and Sert). In addition, the levels of NE/5HT and their metabolites MHPG/5HIAA were analyzed in the amygdala and hippocampus. Locomotor activity showed a free-running phenotype with a longer period (>24 hours) and showed misalignment between the light-dark and inactive-active cycles. The amplitude of the day-night fluctuation of Bmal1 expression was reduced in the amygdala and hippocampus of light-dark-shifted mice. Net gene expression in the Shift group showed different profiles compared with the Control group. In addition, NE and 5HT levels in the amygdala of the Shift group increased during the active period. The present results suggest that misalignment of the internal and external clocks by continuous shifting of the light-dark cycle affects the circadian clocks and monoamine metabolism in the amygdala and hippocampus of mice. Copyright © 2015 Elsevier B.V. All rights reserved.

Long-lasting beneficial effects of central serotonin receptor 7 stimulation in female mice modeling Rett syndrome

PubMed Central

De Filippis, Bianca; Chiodi, Valentina; Adriani, Walter; Lacivita, Enza; Mallozzi, Cinzia; Leopoldo, Marcello; Domenici, Maria Rosaria; Fuso, Andrea; Laviola, Giovanni

2015-01-01

Rett syndrome (RTT) is a rare neurodevelopmental disorder, characterized by severe behavioral and physiological symptoms. Mutations in the methyl CpG binding protein 2 gene (MECP2) cause more than 95% of classic cases, and currently there is no cure for this devastating disorder. Recently we have demonstrated that specific behavioral and brain molecular alterations can be rescued in MeCP2-308 male mice, a RTT mouse model, by pharmacological stimulation of the brain serotonin receptor 7 (5-HT7R). This member of the serotonin receptor family—crucially involved in the regulation of brain structural plasticity and cognitive processes—can be stimulated by systemic repeated treatment with LP-211, a brain-penetrant selective 5-HT7R agonist. The present study extends previous findings by demonstrating that the LP-211 treatment (0.25 mg/kg, once per day for 7 days) rescues RTT-related phenotypic alterations, motor coordination (Dowel test), spatial reference memory (Barnes maze test) and synaptic plasticity (hippocampal long-term-potentiation) in MeCP2-308 heterozygous female mice, the genetic and hormonal milieu that resembles that of RTT patients. LP-211 also restores the activation of the ribosomal protein (rp) S6, the downstream target of mTOR and S6 kinase, in the hippocampus of RTT female mice. Notably, the beneficial effects on neurobehavioral and molecular parameters of a seven-day long treatment with LP-211 were evident up to 2 months after the last injection, thus suggesting long-lasting effects on RTT-related impairments. Taken together with our previous study, these results provide compelling preclinical evidence of the potential therapeutic value for RTT of a pharmacological approach targeting the brain 5-HT7R. PMID:25926782

Neurochemical factors associated with the antidepressant-like effect of flavonoid chrysin in chronically stressed mice.

PubMed

Filho, Carlos Borges; Jesse, Cristiano Ricardo; Donato, Franciele; Del Fabbro, Lucian; de Gomes, Marcelo Gomes; Goes, André Tiago Rossito; Souza, Leandro Cattelan; Giacomeli, Renata; Antunes, Michelle; Luchese, Cristiane; Roman, Silvane Souza; Boeira, Silvana Peterini

2016-11-15

Chrysin is a flavonoid which is found in bee propolis, honey and various plants. Antidepressant-like effect of chrysin in chronically stressed mice was previously demonstrated by our group. Conversely, neurochemical factors associated with this effect require further investigations. Thus, we investigated the possible involvement of pro-inflammatory cytokines, kynurenine pathway (KP), 5-hydroxytryptamine (5-HT) metabolism and caspases activities in the effect of chrysin in mice exposed to unpredictable chronic stress (UCS). UCS applied for 28 days induced a depressive-like behavior, characterized by decrease in the time of grooming in the splash test and by increase in the immobility time in the tail suspension test. Oral treatment with chrysin (5 or 20mg/kg, 28 days), similarly to fluoxetine (10mg/kg, positive control), culminated in the prevention of these alterations. UCS elevated plasma levels of corticotropin-releasing hormone and adrenocorticotropic hormone, as well the tumor necrosis factor-α, interleukin-1β, interleukin-6 and kynurenine levels in the prefrontal cortex (PFC) and hippocampus (HP). UCS induced the decrease in the 5-HT levels in the HP and the increase in the indoleamine-2,3-dioxygenase, caspase 3 and 9 activities in the PFC and HP. Treatment with chrysin, similarly to fluoxetine, promoted the attenuation of these alterations occasioned by UCS. These results corroborated with the antidepressant potential of chrysin in the treatment of psychiatric diseases. Furthermore, this work indicated the association of pro-inflammatory cytokines synthesis, KP, 5-HT metabolism and caspases activities with the action exercised by chrysin in mice exposed to UCS. Copyright © 2016 Elsevier B.V. All rights reserved.

Behavioral and monoamine perturbations in adult male mice with chronic inflammation induced by repeated peripheral lipopolysaccharide administration.

PubMed

Krishna, Saritha; Dodd, Celia A; Filipov, Nikolay M

2016-04-01

Considering the limited information on the ability of chronic peripheral inflammation to induce behavioral alterations, including on their persistence after inflammatory stimuli termination and on associated neurochemical perturbations, this study assessed the effects of chronic (0.25 mg/kg; i.p.; twice weekly) lipopolysaccharide (LPS) treatment on selected behavioral, neurochemical and molecular measures at different time points in adult male C57BL/6 mice. Behaviorally, LPS-treated mice were hypoactive after 6 weeks, whereas significant hyperactivity was observed after 12 weeks of LPS and 11 weeks after 13 week LPS treatment termination. Similar biphasic responses, i.e., early decrease followed by a delayed increase were observed in the open field test center time, suggestive of, respectively, increased and decreased anxiety. In a forced swim test, mice exhibited increased immobility (depressive behavior) at all times they were tested. Chronic LPS also produced persistent increase in splenic serotonin (5-HT) and time-dependent, brain region-specific alterations in striatal and prefrontocortical dopamine and 5-HT homeostasis. Microglia, but not astrocytes, were activated by LPS early and late, but their activation did not persist after LPS treatment termination. Above findings demonstrate that chronic peripheral inflammation initially causes hypoactivity and increased anxiety, followed by persistent hyperactivity and decreased anxiety. Notably, chronic LPS-induced depressive behavior appears early, persists long after LPS termination, and is associated with increased splenic 5-HT. Collectively, our data highlight the need for a greater focus on the peripheral/central monoamine alterations and lasting behavioral deficits induced by chronic peripheral inflammation as there are many pathological conditions where inflammation of a chronic nature is a hallmark feature. Copyright © 2016 Elsevier B.V. All rights reserved.

Control of Amygdala Circuits by 5-HT Neurons via 5-HT and Glutamate Cotransmission.

PubMed

Sengupta, Ayesha; Bocchio, Marco; Bannerman, David M; Sharp, Trevor; Capogna, Marco

2017-02-15

The serotonin (5-HT) system and the amygdala are key regulators of emotional behavior. Several lines of evidence suggest that 5-HT transmission in the amygdala is implicated in the susceptibility and drug treatment of mood disorders. Therefore, elucidating the physiological mechanisms through which midbrain 5-HT neurons modulate amygdala circuits could be pivotal in understanding emotional regulation in health and disease. To shed light on these mechanisms, we performed patch-clamp recordings from basal amygdala (BA) neurons in brain slices from mice with channelrhodopsin genetically targeted to 5-HT neurons. Optical stimulation of 5-HT terminals at low frequencies (≤1 Hz) evoked a short-latency excitation of BA interneurons (INs) that was depressed at higher frequencies. Pharmacological analysis revealed that this effect was mediated by glutamate and not 5-HT because it was abolished by ionotropic glutamate receptor antagonists. Optical stimulation of 5-HT terminals at higher frequencies (10-20 Hz) evoked both slow excitation and slow inhibition of INs. These effects were mediated by 5-HT because they were blocked by antagonists of 5-HT 2A and 5-HT 1A receptors, respectively. These fast glutamate- and slow 5-HT-mediated responses often coexisted in the same neuron. Interestingly, fast-spiking and non-fast-spiking INs displayed differential modulation by glutamate and 5-HT. Furthermore, optical stimulation of 5-HT terminals did not evoke glutamate release onto BA principal neurons, but inhibited these cells directly via activation of 5-HT 1A receptors and indirectly via enhanced GABA release. Collectively, these findings suggest that 5-HT neurons exert a frequency-dependent, cell-type-specific control over BA circuitry via 5-HT and glutamate co-release to inhibit the BA output. SIGNIFICANCE STATEMENT The modulation of the amygdala by serotonin (5-HT) is important for emotional regulation and is implicated in the pathogenesis and treatment of affective disorders. Therefore, it is essential to determine the physiological mechanisms through which 5-HT neurons in the dorsal raphe nuclei modulate amygdala circuits. Here, we combined optogenetic, electrophysiological, and pharmacological approaches to study the effects of activation of 5-HT axons in the basal nucleus of the amygdala (BA). We found that 5-HT neurons co-release 5-HT and glutamate onto BA neurons in a cell-type-specific and frequency-dependent manner. Therefore, we suggest that theories on the contribution of 5-HT neurons to amygdala function should be revised to incorporate the concept of 5-HT/glutamate cotransmission. Copyright © 2017 Sengupta et al.

Control of Amygdala Circuits by 5-HT Neurons via 5-HT and Glutamate Cotransmission

PubMed Central

Bannerman, David M.

2017-01-01

The serotonin (5-HT) system and the amygdala are key regulators of emotional behavior. Several lines of evidence suggest that 5-HT transmission in the amygdala is implicated in the susceptibility and drug treatment of mood disorders. Therefore, elucidating the physiological mechanisms through which midbrain 5-HT neurons modulate amygdala circuits could be pivotal in understanding emotional regulation in health and disease. To shed light on these mechanisms, we performed patch-clamp recordings from basal amygdala (BA) neurons in brain slices from mice with channelrhodopsin genetically targeted to 5-HT neurons. Optical stimulation of 5-HT terminals at low frequencies (≤1 Hz) evoked a short-latency excitation of BA interneurons (INs) that was depressed at higher frequencies. Pharmacological analysis revealed that this effect was mediated by glutamate and not 5-HT because it was abolished by ionotropic glutamate receptor antagonists. Optical stimulation of 5-HT terminals at higher frequencies (10–20 Hz) evoked both slow excitation and slow inhibition of INs. These effects were mediated by 5-HT because they were blocked by antagonists of 5-HT2A and 5-HT1A receptors, respectively. These fast glutamate- and slow 5-HT-mediated responses often coexisted in the same neuron. Interestingly, fast-spiking and non-fast-spiking INs displayed differential modulation by glutamate and 5-HT. Furthermore, optical stimulation of 5-HT terminals did not evoke glutamate release onto BA principal neurons, but inhibited these cells directly via activation of 5-HT1A receptors and indirectly via enhanced GABA release. Collectively, these findings suggest that 5-HT neurons exert a frequency-dependent, cell-type-specific control over BA circuitry via 5-HT and glutamate co-release to inhibit the BA output. SIGNIFICANCE STATEMENT The modulation of the amygdala by serotonin (5-HT) is important for emotional regulation and is implicated in the pathogenesis and treatment of affective disorders. Therefore, it is essential to determine the physiological mechanisms through which 5-HT neurons in the dorsal raphe nuclei modulate amygdala circuits. Here, we combined optogenetic, electrophysiological, and pharmacological approaches to study the effects of activation of 5-HT axons in the basal nucleus of the amygdala (BA). We found that 5-HT neurons co-release 5-HT and glutamate onto BA neurons in a cell-type-specific and frequency-dependent manner. Therefore, we suggest that theories on the contribution of 5-HT neurons to amygdala function should be revised to incorporate the concept of 5-HT/glutamate cotransmission. PMID:28087766

Blockade of the 5-HT transporter contributes to the behavioural, neuronal and molecular effects of cocaine.

PubMed

Simmler, Linda D; Anacker, Allison M J; Levin, Michael H; Vaswani, Nina M; Gresch, Paul J; Nackenoff, Alex G; Anastasio, Noelle C; Stutz, Sonja J; Cunningham, Kathryn A; Wang, Jing; Zhang, Bing; Henry, L Keith; Stewart, Adele; Veenstra-VanderWeele, Jeremy; Blakely, Randy D

2017-08-01

The psychostimulant cocaine induces complex molecular, cellular and behavioural responses as a consequence of inhibiting presynaptic dopamine, noradrenaline and 5-HT transporters. To elucidate 5-HT transporter (SERT)-specific contributions to cocaine action, we evaluated cocaine effects in the SERT Met172 knock-in mouse, which expresses a SERT coding substitution that eliminates high-affinity cocaine recognition. We measured the effects of SERT Met172 on cocaine antagonism of 5-HT re-uptake using ex vivo synaptosome preparations and in vivo microdialysis. We assessed SERT dependence of cocaine actions behaviourally through acute and chronic locomotor activation, sensitization, conditioned place preference (CPP) and oral cocaine consumption. We used c-Fos, quantitative RT-PCR and RNA sequencing methods for insights into cellular and molecular networks supporting SERT-dependent cocaine actions. SERT Met172 mice demonstrated functional insensitivity for cocaine at SERT. Although they displayed wild-type levels of acute cocaine-induced hyperactivity or chronic sensitization, the pattern of acute motor activation was different, with a bias toward thigmotaxis. CPP was increased, and a time-dependent elevation in oral cocaine consumption was observed. SERT Met172 mice displayed relatively higher levels of neuronal activation in the hippocampus, piriform cortex and prelimbic cortex (PrL), accompanied by region-dependent changes in immediate early gene expression. Distinct SERT-dependent gene expression networks triggered by acute and chronic cocaine administration were identified, including PrL Akt and nucleus accumbens ERK1/2 signalling. Our studies reveal distinct SERT contributions to cocaine action, reinforcing the possibility of targeting specific aspects of cocaine addiction by modulation of 5-HT signalling. © 2017 The British Pharmacological Society.

Inhibition of serotonin transporters disrupts the enhancement of fear memory extinction by 3,4-methylenedioxymethamphetamine (MDMA).

PubMed

Young, Matthew B; Norrholm, Seth D; Khoury, Lara M; Jovanovic, Tanja; Rauch, Sheila A M; Reiff, Collin M; Dunlop, Boadie W; Rothbaum, Barbara O; Howell, Leonard L

2017-10-01

3,4-Methylenedioxymethamphetamine (MDMA) persistently improves symptoms of post-traumatic stress disorder (PTSD) when combined with psychotherapy. Studies in rodents suggest that these effects can be attributed to enhancement of fear memory extinction. Therefore, MDMA may improve the effects of exposure-based therapy for PTSD, particularly in treatment-resistant patients. However, given MDMA's broad pharmacological profile, further investigation is warranted before moving to a complex clinical population. We aimed to inform clinical research by providing a translational model of MDMA's effect, and elucidating monoaminergic mechanisms through which MDMA enhances fear extinction. We explored the importance of monoamine transporters targeted by MDMA to fear memory extinction, as measured by reductions in conditioned freezing and fear-potentiated startle (FPS) in mice. Mice were treated with selective inhibitors of individual monoamine transporters prior to combined MDMA treatment and fear extinction training. MDMA enhanced the lasting extinction of FPS. Acute and chronic treatment with a 5-HT transporter (5-HTT) inhibitor blocked MDMA's effect on fear memory extinction. Acute inhibition of dopamine (DA) and norepinephrine (NE) transporters had no effect. 5-HT release alone did not enhance extinction. Blockade of MDMA's effect by 5-HTT inhibition also downregulated 5-HT 2A -mediated behavior, and 5-HT 2A antagonism disrupted MDMA's effect on extinction. We validate enhancement of fear memory extinction by MDMA in a translational behavioral model, and reveal the importance of 5-HTT and 5-HT 2A receptors to this effect. These observations support future clinical research of MDMA as an adjunct to exposure therapy, and provide important pharmacological considerations for clinical use in a population frequently treated with 5-HTT inhibitors.

Cetuximab improves AZD6244 antitumor activity in colorectal cancer HT29 cells in vitro and in nude mice by attenuating HER3/Akt pathway activation.

PubMed

Zhang, Qin; Xiao, He; Jin, Feng; Li, Mengxia; Luo, Jia; Wang, Ge

2018-07-01

The present study investigated the molecular mechanism by which the epidermal growth factor receptor (EGFR) inhibitor cetuximab enhances the antitumor activity of the mitogen-activated protein kinase kinase (MEK) inhibitor AZD6244 in colorectal cancer HT29 cells. HT29 cells were treated with AZD6244 plus cetuximab and then subjected to the following assays: Cell Counting kit-8, BrdU-incorporation, flow cytometric cell cycle distribution and apoptosis analysis, western blot analysis, and nude mouse xenografts. The combination of AZD6244 and cetuximab significantly reduced HT29 cell viability and proliferation compared with AZD6244 alone. The combination treatment reduced the IC 50 value from 108.12±10.05 to 28.45±1.92 nM. AZD6244 and cetuximab also induced cell cycle arrest at G1 phase and reduced S phase (88.53% vs. 93.39%, P=0.080; 8.73% vs. 4.24%, P=0.082, respectively). Combination of AZD6244 with cetuximab significantly induced tumor cells apoptosis (14.61% vs. 8.99%, P=0.046). Inhibition of EGFR activity using cetuximab partially abrogated the feedback-activation of phosphorylated receptor tyrosine-protein kinase erB-3 (p-HER3) and p-AKT serine/threonine kinase (AKT), as well as prevented reactivation of p-extracellular regulated kinase (ERK) conferred by AZD6244 treatment. Combination of AZD6244 and cetuximab also inhibited HT29 cell xenograft growth in nude mice and suppressed HER3 and p-AKT levels in xenografts. The EGFR inhibitor cetuximab enhanced the antitumor activity of the MEK inhibitor AZD6244 in colorectal cells in vitro and in vivo . Co-inhibition of MEK and EGFR may be a promising treatment strategy in colorectal cancers.

Persistent effects of chronic clozapine on the cellular and behavioral responses to LSD in mice

PubMed Central

Moreno, José L.; Holloway, Terrell; Umali, Adrienne; Rayannavar, Vinayak; Sealfon, Stuart C.

2013-01-01

Rationale In schizophrenia patients, optimal treatment with antipsychotics requires weeks to months of sustained drug therapy. However, single administration of antipsychotic drugs can reverse schizophrenia-like behavioral alterations in rodent models of psychosis. This raises questions about the physiological relevance of such antipsychotic-like activity. Objective This study evaluates the effects of chronic treatment with clozapine on the cellular and behavioral responses induced by the hallucinogenic serotonin 5-HT2A receptor agonist lysergic acid diethylamide (LSD) as a mouse model of psychosis. Method Mice were treated chronically (21 days) with 25 mg/kg/day clozapine. Experiments were conducted 1, 7, 14, and 21 days after the last clozapine administration. [3H]Ketanserin binding and 5-HT2A mRNA expression were determined in mouse somatosensory cortex. Head-twitch behavior, expression of c-fos, which is induced by all 5-HT2A agonists, and expression of egr-1 and egr-2, which are LSD-like specific, were assayed. Results Head-twitch response was decreased and [3H]ketanserin binding was downregulated in 1, 7, and 14 days after chronic clozapine. 5-HT2A mRNA was reduced 1 day after chronic clozapine. Induction of c-fos, but not egr-1 and egr-2, was rescued 7 days after chronic clozapine. These effects were not observed after short treatment (2 days) with clozapine or chronic haloperidol (1 mg/kg/day). Conclusion Our findings provide a murine model of chronic atypical antipsychotic drug action and suggest downregulation of the 5-HT2A receptor as a potential mechanism involved in these persistent therapeutic-like effects. PMID:22842765

Tropisetron attenuates cisplatin-induced nephrotoxicity in mice.

PubMed

Zirak, Mohammad Reza; Rahimian, Reza; Ghazi-Khansari, Mahmoud; Abbasi, Ata; Razmi, Ali; Mehr, Shahram Ejtemaei; Mousavizadeh, Kazem; Dehpour, Ahmad Reza

2014-09-05

Nephrotoxicity is one of the most important complications of cisplatin, a potent chemotherapeutic agent used in the treatment of various malignancies. 5-HT3 antagonists are widely used to counteract chemotherapy-induced emesis and new studies reveal that they poses notable anti-inflammatory properties. In current study, we investigated the effects of 5-HT3 antagonists on cisplatin induced nephrotoxicity in mice. To identify the underlying mechanism of renal protection by tropisetron, we investigated the probable involvement of alpha7 nicotinic acetylcholine receptor (α7nAChR). A single injection of cisplatin (20mg/kg; i.p) induced nephrotoxicity, 5-HT3 antagonists (tropisetron, granisetron and ondansetron,) were given twice daily for 3 day (3mg/kg; i.p). Finally animals were euthanized and blood sample was collected to measure urea and creatinin level. Also kidneys were removed for histopathological examination and biochemical measurements including glutathione (GSH), malondialdehyde (MDA), superoxide dismutase (SOD) activity, inducible nitric oxide synthase (iNOS) expression and inflammatory cytokines. Tropisetron decreased the expression of inflammatory molecules including tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β) and iNOS and improved histopathological damage and renal dysfunction. However other 5-HT3 antagonists, granisetron or ondansetron do not have any elicit effects on biochemical markers and histological damages. Since methyllycaconitine, antagonist of α7nAChR, was unable to reverse the beneficial effect of tropisetron, we concluded that this effect of tropisetron is not mediated by α7nAChR.Our results showed that tropisetron treatment markedly ameliorated the experimental cisplatin induced-nephrotoxicity and this effect might be 5-HT3 receptor and α7nAChR independent. Copyright © 2014 Elsevier B.V. All rights reserved.

Cannabidiol attenuates haloperidol-induced catalepsy and c-Fos protein expression in the dorsolateral striatum via 5-HT1A receptors in mice.

PubMed

Sonego, Andreza B; Gomes, Felipe V; Del Bel, Elaine A; Guimaraes, Francisco S

2016-08-01

Cannabidiol (CBD) is a major non-psychoactive compound from Cannabis sativa plant. Given that CBD reduces psychotic symptoms without inducing extrapyramidal motor side-effects in animal models and schizophrenia patients, it has been proposed to act as an atypical antipsychotic. In addition, CBD reduced catalepsy induced by drugs with distinct pharmacological mechanisms, including the typical antipsychotic haloperidol. To further investigate this latter effect, we tested whether CBD (15-60mg/kg) would attenuate the catalepsy and c-Fos protein expression in the dorsal striatum induced by haloperidol (0.6mg/kg). We also evaluated if these effects occur through the facilitation of 5-HT1A receptor-mediated neurotransmission. For this, male Swiss mice were treated with CBD and haloperidol systemically and then subjected to the catalepsy test. Independent groups of animals were also treated with the 5-HT1A receptor antagonist WAY100635 (0.1mg/kg). As expected, haloperidol induced catalepsy throughout the experiments, an effect that was prevented by systemic CBD treatment 30min before haloperidol administration. Also, CBD, administered 2.5h after haloperidol, reversed haloperidol-induced catalepsy. Haloperidol also increased c-Fos protein expression in the dorsolateral striatum, an effect attenuated by previous CBD administration. CBD effects on catalepsy and c-Fos protein expression induced by haloperidol were blocked by the 5-HT1A receptor antagonist. We also evaluated the effects of CBD (60nmol) injection into the dorsal striatum on haloperidol-induced catalepsy. Similar to systemic administration, this treatment reduced catalepsy induced by haloperidol. Altogether, these results suggest that CBD acts in the dorsal striatum to improve haloperidol-induced catalepsy via postsynaptic 5-HT1A receptors. Copyright © 2016 Elsevier B.V. All rights reserved.

Esculetin Attenuates the Growth of Lung Cancer by Downregulating Wnt Targeted Genes and Suppressing NF-κB.

PubMed

Zhu, Xiangyun; Gu, Jiaping; Qian, Hongxian

2018-03-01

Esculetin was identified to inhibit cell proliferation and induce apoptosis or cell cycle arrest in several cancer cell lines. However, the effect of esculetin on lung cancer remains elusive. The anti-proliferative role of esculetin in murine Lewis lung carcinoma (LLC) cells was evaluated by 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) and colony formation assays. BALB/c mice were subcutaneously injected with LLC cells to investigate the inhibitory effect of esculetin on the growth of lung cancer xenograft. Invasive ability was detected in esculetin treated and untreated LLC cells by transwell assay. The association between esculetin and Wnt/β-catenin signaling, as well as nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), was confirmed by testing the expression of c-myc, Cyclin D1 and NF-κB using Western blot. Esculetin treatment in LLC cells led to significant decrease of cell proliferation in a time- and dose-dependent manner. After injection of LLC cells into mice, reduced size and weight of tumors were observed in esculetin treated mice compared to untreated mice. However, no difference in cell invasion was observed between the treated and untreated LLC cells. Notably decreased expression of c-myc, Cyclin D1 and NF-κB were observed in LLC cells with esculetin treatment compared to untreated cells. Esculetin plays an inhibitory role in the growth of lung cancer by down-regulating c-myc, Cyclin D1 and NF-κB. Copyright © 2017 SEPAR. Publicado por Elsevier España, S.L.U. All rights reserved.

Methylprednisolone acetate induces, and Δ7-dafachronic acid suppresses, Strongyloides stercoralis hyperinfection in NSG mice.

PubMed

Patton, John B; Bonne-Année, Sandra; Deckman, Jessica; Hess, Jessica A; Torigian, April; Nolan, Thomas J; Wang, Zhu; Kliewer, Steven A; Durham, Amy C; Lee, James J; Eberhard, Mark L; Mangelsdorf, David J; Lok, James B; Abraham, David

2018-01-02

Strongyloides stercoralis hyperinfection causes high mortality rates in humans, and, while hyperinfection can be induced by immunosuppressive glucocorticoids, the pathogenesis remains unknown. Since immunocompetent mice are resistant to infection with S. stercoralis , we hypothesized that NSG mice, which have a reduced innate immune response and lack adaptive immunity, would be susceptible to the infection and develop hyperinfection. Interestingly, despite the presence of large numbers of adult and first-stage larvae in S. stercoralis -infected NSG mice, no hyperinfection was observed even when the mice were treated with a monoclonal antibody to eliminate residual granulocyte activity. NSG mice were then infected with third-stage larvae and treated for 6 wk with methylprednisolone acetate (MPA), a synthetic glucocorticoid. MPA treatment of infected mice resulted in 50% mortality and caused a significant >10-fold increase in the number of parasitic female worms compared with infected untreated mice. In addition, autoinfective third-stage larvae, which initiate hyperinfection, were found in high numbers in MPA-treated, but not untreated, mice. Remarkably, treatment with Δ7-dafachronic acid, an agonist of the parasite nuclear receptor Ss -DAF-12, significantly reduced the worm burden in MPA-treated mice undergoing hyperinfection with S. stercoralis Overall, this study provides a useful mouse model for S. stercoralis autoinfection and suggests a therapeutic strategy for treating lethal hyperinfection.

Monoamines and glycogen levels in cerebral cortices of fast and slow methionine sulfoximine-inbred mice.

PubMed

Boissonnet, Arnaud; Hévor, Tobias; Landemarre, Ludovic; Cloix, Jean-François

2013-05-01

The experimental model of seizures which depends upon methionine sulfoximine (MSO) simulates the most striking form of human epilepsy. MSO generates epileptiform seizures in a large variety of animals, increases brain glycogen content and induces brain monoamines modifications. We selected two inbred lines of mice based upon their latency toward MSO-dependent seizures, named as MSO-Fast (sensitive), having short latency toward MSO, and MSO-Slow (resistant) with a long latency. We determined 13 monoamines and glycogen contents in brain cortices of the MSO-Fast and slow lines in order to determine the relationships with MSO-dependent seizures. The present data show that using these MSO-Fast and MSO-Slow inbred lines it could be demonstrated that: (1) in basal conditions the neurotransmitter 5-HT is significantly higher in MSO-Fast mice than in MSO-Slow ones; (2) MSO in both lines induced a significant increase in brain content of DOPAC (3,4-dihydroxyphenylacetic acid), HVA (homovanillic acid), MHPG (3-methoxy-4-hydroxyphenylglycol), and 5-HT (serotonin); a significant decrease in MSO-Slow mice in brain content of NME (normetepinephrine), and 5-HIAA (5-hydroxyindoleacetic acid) and the variation of other monoamines were not significant; (3) the brain glycogen content is significantly higher in MSO-Fast mice than in MSO-Slow ones, both in basal conditions and after MSO administration. From our data, we propose that brain glycogen content may constitute a defense against epileptic attack, as glycogen may be degraded down to glucose-6-phosphate that can be used to either postpone the epileptic attack or to provide neurons with energy when they needed it. Brain glycogen might therefore be considered as a molecule that can contribute to struggle seizures, at least in MSO-dependent seizure. The 5-HT content may constitute a defense against MSO-dependent epilepsy. Copyright © 2013 Elsevier B.V. All rights reserved.

Potential antimalarial activity of Methyl Jasmonate and its effect on lipid profiles in Plasmodium Berghei infected mice.

PubMed

Oyinloye, Oladapo E; Kosoko, Ayokulehin M; Emikpe, Benjamin; Falade, Catherine O; Ademowo, Olusegun G

2015-09-01

The antimalarial activity and lipid profiles of Methyl Jasmonate (MJ) were investigated against established malaria infection in vivo using BALB/c mice. Arteether (AE) and chloroquine (CQ) were used as reference drugs while ethanol was used as the vehicle for drug delivery for MJ. Mice treated with 10 and 25 mg/kg MJ showed a remarkable reduction in percentage parasitemia by 68.3% and 78.2% on day 10(post treatment) respectively while 45.4% and 87.2% reduction in percentage parasitemia were observed in the group treated with 50 mg/kg on day 3 and 10 (post treatment) respectively. The highest mean survival time was observed in CQ followed by AE and MJ in dose-dependent manner. A progressive decrease in packed cell volume (PCV) was observed in infected untreated mice which led to the death of all the mice by day 9 (post treatment). Infected mice treated with MJ showed reduced level of HDL and LDL compared with infected untreated group. As the dose of MJ increased in infected mice cholesterol levels increased while there was reduction in triglyceride. Overall there was marked decrease in parasitemia in Plasmodium berghei infected mice treated with graded doses of MJ but appears to have reduced antimalarial activity compared with CQ and AE.

[Killing effect of Huaier combined with DC-CIK on nude mice bearing colon cancer HT29 stem cells in vivo].

PubMed

Sun, Wen-Wen; Dou, Jin-Xia; Zhang, Lin; Qiao, Li-Kui; Shen, Na; Gao, Wen-Yuan

2018-01-01

To compare the therapeutic effects of different treatment methods on the nude mice bearing colon cancer HT29 cells. BalB/C nude mice colon cancer stem cell models were established and randomly divided into the following four groups, with 8 nude mice in each group: blank control group, DC-CIK group, Huaier group, and Huaier combined with DC-CIK group (combined treatment group). The mice in DC-CIK group and combined treatment group received 1×10⁶ DC-CIK cells treatment by tail vein injectionafter the tumor stem cells were inoculated for 4 days,2 times a week for three weeks. The mice in Huaier group and combined treatment group received intragastric administration at the dose of 20 g/60 kg body weight, 0.2 mL/time, once a day for a total of three weeks. The mice in control group received equal volume of normal saline. Tumor size and body weight of nude mice were measured every 2 days during treatment for three weeks in each group. After the treatment, the nude mice were sacrificed to measure the tumor weight and the tumor inhibition rate was calculated. The RT-PCR method was used to detect the expression levels of the key genes in the signal pathway. After the end of the treatment, the quality of the tumor in the Huaier group, DC-CIK group and combined treatment group was significantly lower than that in the control group; the quality in combined treatment group was significantly lower than that in Huaier group and DC-CIK group.Among them, the tumor inhibition rate reached 46.77% in the combined treatment group. In respect of changes in expression levels of key genes in the signaling pathway, the mRNA expression levels of key genes PI3KR1 and Akt in PI3K/Akt pathway, key genes Wnt1 and CTTNB1 in Wnt/ β -catenin pathway, and key genes Notch1, Notch2, Notch3 in Notch pathway in the combined treatment group were lower than those in DC-CIK group and Huaier group. The Huaier combined with DC-CIK group showed best therapeutic effect among different treatment methods for HT29 stemcell colon tumors in nude mice, providing a new idea for clinical treatment of colon cancer. Copyright© by the Chinese Pharmaceutical Association.

Behavioural profiles in the mouse defence test battery suggest anxiolytic potential of 5-HT(1A) receptor antagonists.

PubMed

Griebel, G; Rodgers, R J; Perrault, G; Sanger, D J

1999-05-01

Compounds varying in selectivity as 5-HT1A receptor antagonists have recently been reported to produce anxiolytic-like effects comparable to those of benzodiazepines in the mouse elevated plus-maze procedure. In view of the potential clinical significance of these findings, the present experiments compared the behavioural effects of diazepam (0.5-3.0 mg/kg) with those of several non-selective 5-HT1A receptor antagonists [NAN-190, 0.1-3.0 mg/kg, MM-77, 0.03-1.0 mg/kg, (S)-UH-301, 0.3-3.0 mg/kg and pindobind-5-HT1A, 0.03-1.0 mg/kg], and three selective 5-HT1A receptor antagonists (WAY100635, 0.01-3.0 mg/kg, p-MPPI, 0.1-3.0 mg/kg and SL88.0338, 0.3-3.0 mg/kg) in the mouse defence test battery (MDTB). In this well-validated anxiolytic screening test, Swiss mice are directly confronted with a natural threat (a rat) as well as situations associated with this threat. Primary measures taken during and after rat confrontation were flight, risk assessment (RA), defensive threat/attack and escape attempts. Diazepam significantly decreased flight reactions after the rat was introduced into the runway, reduced RA activities of mice chased by the rat, increased RA responses displayed when subjects were constrained in a straight alley and reduced defensive upright postures and biting upon forced contact. All the selective 5-HT1A receptor antagonists and NAN-190 also reduced flight, RA in the chase test, and defensive threat and attack behaviours. (S)-UH-301 and pindobind-5-HT1A reduced RA in the chase test, but only partially modified defensive threat and attack. Unlike the other drugs tested, MM-77 produced significant effects only at doses which also markedly reduced spontaneous locomotor activity, suggesting a behaviourally non-specific action. In contrast to diazepam, the 5-HT1A receptor ligands failed to affect RA in the straight alley test. Following removal of the rat from the test area, only diazepam and (S)-UH-301 reduced escape behaviour (contextual defence) at doses which did not decrease locomotion. Overall, the present findings indicate that except for one RA behaviour and escape responses, the 5-HT1A receptor ligands studied modified the same defensive behaviours as diazepam, suggesting potential therapeutic efficacy in the management of anxiety disorders. However, the magnitude of the effects of the 5-HT1A compounds on defence was generally smaller than that of the benzodiazepine. As all of the 5-HT1A compounds tested in this series share antagonistic activity in models of postsynaptic 5-HT1A receptor function, it is proposed that this action accounts for their effects on defence.

The GABAergic Gudden's dorsal tegmental nucleus: A new relay for serotonergic regulation of sleep-wake behavior in the mouse.

PubMed

Chazalon, Marine; Dumas, Sylvie; Bernard, Jean-François; Sahly, Iman; Tronche, François; de Kerchove d'Exaerde, Alban; Hamon, Michel; Adrien, Joëlle; Fabre, Véronique; Bonnavion, Patricia

2018-06-13

Serotonin (5-HT) neurons are involved in wake promotion and exert a strong inhibitory influence on rapid eye movement (REM) sleep. Such effects have been ascribed, at least in part to the action of 5-HT at post-synaptic 5-HT 1A receptors (5-HT 1A R) in the brainstem, a major wake/REM sleep regulatory center. However, the neuroanatomical substrate through which 5-HT 1A R influence sleep remains elusive. We therefore investigated whether a brainstem structure containing a high density of 5-HT 1A R mRNA, the GABAergic Gudden's dorsal tegmental nucleus (DTg), may contribute to 5-HT-mediated regulatory mechanisms of sleep-wake stages. We first found that bilateral lesions of the DTg promote wake at the expense of sleep. In addition, using local microinjections into the DTg in freely moving mice, we showed that local activation of 5-HT 1A R by the prototypical agonist 8-OH-DPAT enhances wake and reduces deeply REM sleep duration. The specific involvement of 5-HT 1A R in the latter effects was further demonstrated by ex vivo extracellular recordings showing that the selective 5-HT 1A R antagonist WAY 100635 prevented DTg neuron inhibition by 8-OH-DPAT. We next found that GABAergic neurons of the ventral DTg exclusively targets/connects glutamatergic neurons of the lateral mammillary nucleus (LM) in the posterior hypothalamus by means of anterograde and retrograde tracing techniques using cre driver mouse lines and a modified rabies virus. Altogether, our findings strongly support the idea that 5-HT-driven enhancement of wake results from 5-HT 1A R-mediated inhibition of DTg GABAergic neurons that would in turn disinhibit glutamatergic neurons in the mammillary bodies. We therefore propose a Raphe→DTg→LM pathway as a novel regulatory circuit underlying 5-HT modulation of arousal. Copyright © 2018. Published by Elsevier Ltd.

Tailoring nanoscale morphology of polymer: Fullerene blends using electrostatic field

DOE PAGES

Elshobaki, Moneim; Gebhardt, Ryan; Carr, John; ...

2016-12-05

In this paper, to tailor the nanoscale phase separation in polymer/fullerene blends, we study the effect of electrostatic field (E-field) on the solidification of poly(3-hexylthiophene-2, 5-diyl) (P3HT):[6,6]-phenyl-C61-butyric acid methyl ester (PC 60BM) bulk heterojunction (BHJ). In addition to untreated sample (control); wet P3HT:PC 60BM thin films were exposed to E-field of Van de Graaff (VDG) generator at three different directions – horizontal (H), tilted (T) and vertical (V) – relative to the plane of the substrate. Surface and bulk characterizations of field-treated BHJs affirm that fullerene molecules can easily penetrate the spaghetti-like P3HT and move up and down following themore » E-field. E-field treatment yields thin films with large P3HT- and PCBM-rich domains acting as continuous pathways for efficient charge separation, transport, and collection. We improve; (1) the hole mobility values up to 19.4 × 10 -4 ± 1.6 × 10 -4 cm 2 V -1 s -1 (117% higher than the control), and (2) power conversion efficient (PCE) of conventional and inverted OPVs recording 2.58 ± 0.02% and 4.1 ± 0.4%. This E-field approach can serve as a new morphology-tuning technique, which is generally applicable to other polymer-fullerene systems.« less

Sedative effect of Clozapine is a function of 5-HT2A and environmental novelty.

PubMed

Joshi, Radhika S; Quadros, Rolen; Drumm, Michael; Ain, Rupasri; Panicker, Mitradas M

2017-01-01

Antipsychotic drugs are the mainstay in the treatment of schizophrenia and bipolar disorder. However, antipsychotics often exhibit sedation or activity suppression among many other side effects, and the factors that influence them remain poorly understood. We now show, using a 5-HT 2A knockout (Htr2a -/- ) mouse, that environmental circumstances can affect suppression of activity induced by the atypical antipsychotic- Clozapine. We observed that Htr2a -/- mice were more resistant to Clozapine-induced suppression of activity (CISA) and this behaviour was dependent on the environment being 'novel'. In their 'home' environment, at identical doses the mice exhibited CISA. Interestingly, the effect of genotype and environmental novelty on CISA could not be extended to the other antipsychotics that were tested, i.e. Haloperidol and Risperidone. Haloperidol-induced activity suppression was independent of context and genotype. Whereas context affected Risperidone-induced activity suppression only in the Htr2a +/+ mice. Furthermore, we observed that caffeine, a stimulant, elicited resistance to CISA similar to that seen in the 'novel' context. Our study establishes a previously unknown interaction between the environmental context, 5-HT 2A and CISA and emphasises the role of non-pharmacological factors such as environment on the effects of the drug, which seem antipsychotic-specific. Our findings should advance the understanding of the side effects of individual antipsychotics and the role of environment to overcome side effects such as sedation. Copyright © 2016 Elsevier B.V. and ECNP. All rights reserved.

Potential antidepressant-like activity of silymarin in the acute restraint stress in mice: Modulation of corticosterone and oxidative stress response in cerebral cortex and hippocampus.

PubMed

Thakare, Vishnu N; Dhakane, Valmik D; Patel, Bhoomika M

2016-10-01

Silymarin is a polyphenolic flavanoid of Silybum marianum, elicited neuroprotection and antidepressant like activity in stressed model. It was found to increase 5-hydroxytryptamine (5-HT) levels in the cortex and dopamine (DA) and norepinephrine (NE) in the cerebellum in normal mice. The aim of the present study was to investigate the potential antidepressant-like activity of silymarin in the acute restraint stress (ARS) in mice. The ARS was induced by immobilizing the mice for a period of 7h using rodent restraint device preventing them for any physical movement. One hour prior to ARS, silymarin was administered at doses of 100mg/kg and 200mg/kg per oral to non stressed and ARS mice. Various behavioral parameters like immobility time in force swim test, locomotor activity in open field test, and biochemical alterations, serum corticosterone, 5-HT, DA, NE level, malondialdehyde (MDA), and antioxidant enzymes (GSH, CAT and SOD) in hippocampus and cerebral cortex in non stressed and ARS subjected mice were investigated. Experimental findings reveals mice subjected to ARS exhibited significant increase immobility time, serum corticosterone, MDA formation and impaired SOD and CAT activities in hippocampus and cerebral cortex as compared to non stressed mice. Silymarin treatment (100mg/kg and 200mg/kg) significantly attenuated immobility time, corticosterone and restored the antioxidant enzymes after ARS. The present experimental findings indicate that silymarin exhibits antidepressant like activity probably either through alleviating oxidative stress by modulation of corticosterone response, and antioxidant defense system in hippocampus and cerebral cortex in ARS mice. Copyright © 2016. Published by Elsevier Urban & Partner Sp. z o.o.

Anti-inflammatory activity of leaf essential oil from Cinnamomum longepaniculatum (Gamble) N. Chao.

PubMed

Du, Yong-Hua; Feng, Rui-Zhang; Li, Qun; Wei, Qin; Yin, Zhong-Qiong; Zhou, Li-Jun; Tao, Cui; Jia, Ren-Yong

2014-01-01

The anti-inflammatory activity of the essential oil from C. longepaniculatum was evaluated by three experimental models including the dimethyl benzene-induced ear edema in mice, the carrageenan-induced paw edema in rat and the acetic acid-induced vascular permeability in mice. The influence of the essential oil on histological changes and prostaglandin E2 (PGE2), histamine and 5-hydroxytryptamine (5-HT) production associated with carrageenan-induced rat paw edema was also investigated. The essential oil (0.5, 0.25, 0.13 ml/kg b.w.) showed significantly inhibition of inflammation along with a dose-dependent manner in the three experimental models. The anti-inflammatory activity of essential oil was occurred both in early and late phase and peaked at 4 h after carrageenan injection. The essential oil resulted in a dose dependent reduction of the paw thickness, connective tissue injury and the infiltration of inflammatory cell. The essential oil also significantly reduced the production of PGE2, histamine and 5-HT in the exudates of edema paw induced by carrageenan. Both the essential oil and indomethacin resulted relative lower percentage inhibition of histamine and 5-HT than that of PGE2 at 4 h after carrageenan injection.

Presynaptic serotonin 2A receptors modulate thalamocortical plasticity and associative learning

PubMed Central

Barre, Alexander; Berthoux, Coralie; De Bundel, Dimitri; Valjent, Emmanuel; Bockaert, Joël; Marin, Philippe; Bécamel, Carine

2016-01-01

Higher-level cognitive processes strongly depend on a complex interplay between mediodorsal thalamus nuclei and the prefrontal cortex (PFC). Alteration of thalamofrontal connectivity has been involved in cognitive deficits of schizophrenia. Prefrontal serotonin (5-HT)2A receptors play an essential role in cortical network activity, but the mechanism underlying their modulation of glutamatergic transmission and plasticity at thalamocortical synapses remains largely unexplored. Here, we show that 5-HT2A receptor activation enhances NMDA transmission and gates the induction of temporal-dependent plasticity mediated by NMDA receptors at thalamocortical synapses in acute PFC slices. Expressing 5-HT2A receptors in the mediodorsal thalamus (presynaptic site) of 5-HT2A receptor-deficient mice, but not in the PFC (postsynaptic site), using a viral gene-delivery approach, rescued the otherwise absent potentiation of NMDA transmission, induction of temporal plasticity, and deficit in associative memory. These results provide, to our knowledge, the first physiological evidence of a role of presynaptic 5-HT2A receptors located at thalamocortical synapses in the control of thalamofrontal connectivity and the associated cognitive functions. PMID:26903620

Animal models of the serotonin syndrome: a systematic review.

PubMed

Haberzettl, Robert; Bert, Bettina; Fink, Heidrun; Fox, Meredith A

2013-11-01

The serotonin syndrome (SS) is a potentially life-threatening disorder in humans which is induced by ingestion of an overdose or by combination of two or more serotonin (5-HT)-enhancing drugs. In animals, acute administration of direct and indirect 5-HT agonists also leads to a set of behavioral and autonomic responses. In the current review, we provide an overview of the existing versions of the animal model of the SS. With a focus on studies in rats and mice, we analyze the frequency of behavioral and autonomic responses following administration of 5-HT-enhancing drugs and direct 5-HT agonists administered alone or in combination, and we briefly discuss the receptor mediation of these responses. Considering species differences, we identify a distinct set of behavioral and autonomic responses that are consistently observed following administration of direct and indirect 5-HT agonists. Finally, we discuss the importance of a standardized assessment of SS responses in rodents and the utility of animal models of the SS in translational studies, and provide suggestions for future research. Copyright © 2013 The Authors. Published by Elsevier B.V. All rights reserved.

Fracture healing with alendronate treatment in the Brtl/+ mouse model of osteogenesis imperfecta

PubMed Central

Meganck, J.A.; Begun, D.L.; McElderry, J.D.; Swick, A.; Kozloff, K.M.; Goldstein, S.A.; Morris, M.D.; Marini, J.C.; Caird, M.S.

2014-01-01

Osteogenesis imperfecta (OI) is a heritable bone dysplasia characterized by increased skeletal fragility. Patients are often treated with bisphosphonates to attempt to reduce fracture risk. However, bisphosphonates reside in the skeleton for many years and long-term administration may impact bone material quality. Acutely, there is concern about risk of non-union of fractures that occur near the time of bisphosphonate administration. This study investigated the effect of alendronate, a potent aminobisphosphonate, on fracture healing. Using the Brtl/+ murine model of type IV OI, tibial fractures were generated in 8-week-old mice that were untreated, treated with alendronate before fracture, or treated before and after fracture. After 2, 3, or 5 weeks of healing, tibiae were assessed using microcomputed tomography (μCT), torsion testing, quantitative histomorphometry, and Raman microspectroscopy. There were no morphologic, biomechanical or histomorphometric differences in callus between untreated mice and mice that received alendronate before fracture. Alendronate treatment before fracture did not cause a significant increase in cartilage retention in fracture callus. Both Brtl/+ and WT mice that received alendronate before and after fracture had increases in the callus volume, bone volume fraction and torque at failure after 5 weeks of healing. Raman microspectroscopy results did not show any effects of alendronate in wild-type mice, but calluses from Brtl/+ mice treated with alendronate during healing had a decreased mineral-to-matrix ratio, decreased crystallinity and an increased carbonate-to-phosphate ratio. Treatment with alendronate altered the dynamics of healing by preventing callus volume decreases later in the healing process. Fracture healing in Brtl/+ untreated animals was not significantly different from animals in which alendronate was halted at the time of fracture. PMID:23774443

Bioenergy and Breast Cancer: A Report on Tumor Growth and Metastasis

PubMed Central

Greenwood, Mark; Schmidt, Jade

2016-01-01

As many as 80% of the 296,000 women and 2,240 men diagnosed with breast cancer in the United States will seek out complementary and alternative medicine (CAM) treatments. One such therapy is Healing Touch (HT), recognized by the National Center for Complementary and Integrative Health (NCCIH) as a treatment modality. Using a multiple experimental groups design, fifty-six six- to eight-week-old Balb/c mice were injected with 4T1 breast cancer tumor cells and randomly divided into intervention and positive control groups. Five days after tumor cell injection, mice in the intervention groups received HT either daily or every other day for 10 minutes by one HT practitioner. At 15 days after tumor cell injection, tumor size was measured, and metastasis was evaluated by a medical pathologist after necropsy. Tumor size did not differ significantly among the groups (F(3,52) = 0.75, p value = 0.53). The presence of metastasis did not differ across groups (chi-square(3) = 3.902, p = 0.272) or when compared within an organ (liver: chi-square(3) = 2.507, p = 0.474; lungs: chi-square(3) = 3.804, p = 0.283; spleen: chi-square(3) = 0.595, p = 0.898). However, these results did indicate a moderate, though insignificant, positive impact of HT and highlight the need for continued research into dose, length of treatment, and measurable outcomes (tumor size, metastasis) to provide evidence to suggest application for nursing care. PMID:27688787

Caffeine improves the ability of serotonin-deficient (Pet-1−/−) mice to survive episodic asphyxia

PubMed Central

Cummings, Kevin J.; Commons, Kathryn G.; Trachtenberg, Felicia L.; Li, Aihua; Kinney, Hannah C.; Nattie, Eugene E.

2015-01-01

Background In neonatal rodents, serotonin (5-HT) neurons are critical for successful autoresuscitation. We hypothesized that caffeine, a respiratory stimulant, would hasten the onset of gasping and improve autoresuscitation in 5-HT-deficient, Pet-1−/− mice. Methods Using a head-out system and electrocardiogram, we measured respiratory and heart rate (HR) responses of Pet-1−/− rodents and their littermates during episodic asphyxia at postnatal days 8–9 (P8–9). After a baseline recording, we injected either vehicle or caffeine (i.p.) at doses of 1, 5, or 10 mg/ kg. We then induced 10 brief (~30 s) episodes of asphyxia, each interspersed with 5 min of room air to allow autoresuscitation. In addition to measuring survival, we measured the duration of hypoxic apnea (time to initiate gasping) and time to recover eupnea and HR. Results Caffeine had a dose-dependent effect of hastening the onset of gasping, recovery of breathing, and restoration of HR in Pet-1−/−(but not in wild-type) rodents, thereby improving survival across asphyxic episodes. Increased survival was strongly correlated with hastened onset of gasping. Conclusion Our data suggest that caffeine reduces mortality relating to asphyxia and 5-HT deficiency. These findings may be relevant for efforts to reduce the incidence of sudden infant death syndrome (SIDS), given that SIDS is associated with failed autoresuscitation and reduced brainstem 5-HT. PMID:23095976

Renin-angiotensin-aldosterone system activity in hyperthyroid cats with and without concurrent hypertension.

PubMed

Williams, T L; Elliott, J; Syme, H M

2013-01-01

Hypertension is present in some hyperthyroid cats at diagnosis or can develop after treatment for hyperthyroidism. Activation of the renin-angiotensin-aldosterone system (RAAS) could be involved in the pathogenesis of hypertension. Hyperthyroid cats that develop hypertension before or after treatment for hyperthyroidism will have greater RAAS activation than normotensive cats. Ninety-nine hyperthyroid cats. Retrospective case-control study. Plasma renin activity (PRA) and plasma aldosterone concentration (PAC) were measured in untreated hyperthyroid hypertensive cats (HT-Pre group), initially normotensive hyperthyroid cats that develop hypertension after treatment (HT-Post group), and hyperthyroid cats that are normotensive (NT group). Data are presented as median [25th, 75th percentile]. Baseline PRA was not significantly different among the 3 groups (HT-Pre group 1.50 [0.05, 2.37] ng/mL/h, HT-Post group 0.66 [0.17, 2.31] ng/mL/h, NT group 1.11 [0.57, 2.18] ng/mL/h; P = .44). PRA decreased significantly after treatment in the NT group (1.09 [0.53, 2.47] versus 0.22 [0.05, 0.76] ng/mL/h; P < .001) and the HT-Post group (0.71 [0.17, 2.33] versus 0.28 [0.07, 0.57] ng/mL/h; P = .006). Baseline PAC was not significantly different among the 3 groups (HT-Pre group 72.2 [40.0, 145.6] pg/mL, HT-Post group 69.7 [43.3, 142.6] pg/mL, NT group 109.0 [68.2, 184.6] pg/mL; P = .10). PAC decreased significantly after treatment in the NT group (114.4 [56.6, 204.1] versus 59.5 [32.4, 98.2] pg/mL; P < .001) but did not change significantly in the HT-Post group (61.2 [44.9, 124.0] versus 58.4 [42.0, 97.7] pg/mL; P = .59). RAAS activation occurs in hyperthyroid cats, but is not associated with the development of hypertension. PAC is not influenced by changes in PRA in hyperthyroid cats that develop hypertension after treatment, perhaps indicating RAAS dysfunction in these cats. Copyright © 2013 by the American College of Veterinary Internal Medicine.

Effect of aminoguanidine and albendazole on inducible nitric oxide synthase (iNOS) activity in T. spiralis-infected mice muscles.

PubMed

Zeromski, Jan; Boczoń, Krystyna; Wandurska-Nowak, Elzbieta; Mozer-Lisewska, Iwona

2005-01-01

The aim of this study was to provide evidence for the expression of iNOS in the cells of inflammatory infiltrates around larvae in skeletal muscles of T. spiralis infected mice. The BALB/c mice (n = 8) divided into subgroups, received either aminoguanidine (AMG)--a specific iNOS inhibitor or albendazole (ALB)--an antiparasitic drug of choice in trichinellosis treatment. Control animals (n = 2 in each subgroup) were either uninfected and treated or uninfected and untreated. Frozen sections of hind leg muscles from mice sacrificed at various time intervals after infection were cut and subjected to immunohistochemistry, using monoclonal anti-iNOS antibody. The ALB-treated mice revealed stronger iNOS staining in the infiltrating cells around larvae than the infected and untreated animals. On the contrary, in the AMG-treated animals, the infiltrating cells did not show any specific iNOS reaction. These data confirm the specificity of iNOS staining in the cellular infiltrates around T. spiralis larvae and shed some light on the role of nitric oxide during ALB treatment in experimental trichinellosis.

5-HT3A -driven green fluorescent protein delineates gustatory fibers innervating sour-responsive taste cells: A labeled line for sour taste?

PubMed

Stratford, J M; Larson, E D; Yang, R; Salcedo, E; Finger, T E

2017-07-01

Taste buds contain multiple cell types with each type expressing receptors and transduction components for a subset of taste qualities. The sour sensing cells, Type III cells, release serotonin (5-HT) in response to the presence of sour (acidic) tastants and this released 5-HT activates 5-HT 3 receptors on the gustatory nerves. We show here, using 5-HT 3A GFP mice, that 5-HT 3 -expressing nerve fibers preferentially contact and receive synaptic contact from Type III taste cells. Further, these 5-HT 3 -expressing nerve fibers terminate in a restricted central-lateral portion of the nucleus of the solitary tract (nTS)-the same area that shows increased c-Fos expression upon presentation of a sour tastant (30 mM citric acid). This acid stimulation also evokes c-Fos in the laterally adjacent mediodorsal spinal trigeminal nucleus (DMSp5), but this trigeminal activation is not associated with the presence of 5-HT 3 -expressing nerve fibers as it is in the nTS. Rather, the neuronal activation in the trigeminal complex likely is attributable to direct depolarization of acid-sensitive trigeminal nerve fibers, for example, polymodal nociceptors, rather than through taste buds. Taken together, these findings suggest that transmission of sour taste information involves communication between Type III taste cells and 5-HT 3 -expressing afferent nerve fibers that project to a restricted portion of the nTS consistent with a crude mapping of taste quality information in the primary gustatory nucleus. © 2017 Wiley Periodicals, Inc.

Antidepressant-like responses to the combined sigma and 5-HT1A receptor agonist OPC-14523.

PubMed

Tottori, K; Miwa, T; Uwahodo, Y; Yamada, S; Nakai, M; Oshiro, Y; Kikuchi, T; Altar, C A

2001-12-01

The antidepressant-like activity of a novel compound, OPC-14523, was investigated in comparison with the conventional antidepressants, fluoxetine and imipramine. OPC-14523 bound with nanomolar affinities to sigma receptors (IC(50)=47-56 nM), the 5-HT(1A) receptor (IC(50)=2.3 nM), and the 5-HT transporter (IC(50)=80 nM). OPC-14523 inhibited the in vitro reuptake of 3H-5-HT (IC(50)=27 nM), but it showed very weak inhibitory activity on 3H-NE and 3H-DA reuptake. OPC-14523 did not inhibit MAO A or B activities or muscarinic receptors. A single oral administration of OPC-14523 produced a marked antidepressant-like effect in the forced swimming test (FST) with rats (ED(50)=27 mg/kg) and mice (ED(50)=20mg/kg) without affecting the general locomotor activity. In contrast, fluoxetine and imipramine each required at least four days of repeated dosing to show this activity. The acute activity of OPC-14523 was blocked by pretreatment with the sigma receptor antagonist NE-100 or the selective 5-HT(1A) receptor antagonist WAY-100635. The induction of flat body posture by OPC-14523 was blocked by the selective 5-HT(1A) receptor antagonist NAN-190, and forebrain 5-HT biosynthesis was attenuated by OPC-14523 at behaviorally effective doses. In contrast, OPC-14523, unlike fluoxetine, failed to inhibit 5-HT reuptake at oral doses below 100mg/kg. Thus, the acute antidepressant-like action of OPC-14523 is achieved by the combined stimulation of sigma and 5-HT(1A) receptors without inhibition of 5-HT reuptake in vivo.

Long-term correction of very long-chain acyl-coA dehydrogenase deficiency in mice using AAV9 gene therapy.

PubMed

Keeler, Allison M; Conlon, Thomas; Walter, Glenn; Zeng, Huadong; Shaffer, Scott A; Dungtao, Fu; Erger, Kirsten; Cossette, Travis; Tang, Qiushi; Mueller, Christian; Flotte, Terence R

2012-06-01

Very long-chain acyl-coA dehydrogenase (VLCAD) is the rate-limiting step in mitochondrial fatty acid oxidation. VLCAD-deficient mice and patients clinical symptoms stem from not only an energy deficiency but also long-chain metabolite accumulations. VLCAD-deficient mice were treated systemically with 1 × 10(12) vector genomes of recombinant adeno-associated virus 9 (rAAV9)-VLCAD. Biochemical correction was observed in vector-treated mice beginning 2 weeks postinjection, as characterized by a significant drop in long-chain fatty acyl accumulates in whole blood after an overnight fast. Changes persisted through the termination point around 20 weeks postinjection. Magnetic resonance spectroscopy (MRS) and tandem mass spectrometry (MS/MS) revealed normalization of intramuscular lipids in treated animals. Correction was not observed in liver tissue extracts, but cardiac muscle extracts showed significant reduction of long-chain metabolites. Disease-specific phenotypes were characterized, including thermoregulation and maintenance of euglycemia after a fasting cold challenge. Internal body temperatures of untreated VLCAD(-/-) mice dropped below 20 °C and the mice became lethargic, requiring euthanasia. In contrast, all rAAV9-treated VLCAD(-/-) mice and the wild-type controls maintained body temperatures. rAAV9-treated VLCAD(-/-) mice maintained euglycemia, whereas untreated VLCAD(-/-) mice suffered hypoglycemia following a fasting cold challenge. These promising results suggest rAAV9 gene therapy as a potential treatment for VLCAD deficiency in humans.

The 5-HT7 receptor in learning and memory. Importance of the hippocampus

PubMed Central

Roberts, Amanda J.; Hedlund, Peter B.

2011-01-01

The 5-HT7 receptor is a more recently discovered G-protein-coupled receptor for serotonin. The functions and possible clinical relevance of this receptor are not yet fully understood. The present paper reviews to what extent the use of animal models of learning and memory and other techniques have implicated the 5-HT7 receptor in such processes. The studies have used a combination of pharmacological and genetic tools targeting the receptor to evaluate effects on behavior and cellular mechanisms. In tests such as the Barnes maze, contextual fear conditioning and novel location recognition that involve spatial learning and memory there is a considerable amount of evidence supporting an involvement of the 5-HT7 receptor. Supporting evidence has also been obtained in studies of mRNA expression and cellular signaling as well as in electrophysiological experiments. Especially interesting are the subtle but distinct effects observed in hippocampus-dependent models of place learning where impairments have been described in mice lacking the 5-HT7 receptor or after administration of a selective antagonist. While more work is required, it appears that 5-HT7 receptors are particularly important in allocentric representation processes. In instrumental learning tasks both procognitive effects and impairments in memory have been observed using pharmacological tools targeting the 5-HT7 receptor. In conclusion, the use of pharmacological and genetic tools in animal studies of learning and memory suggest a potentially important role for the 5-HT7 receptor in cognitive processes. PMID:21484935

Chronic central serotonin depletion attenuates ventilation and body temperature in young but not adult Tph2 knockout rats.

PubMed

Kaplan, Kara; Echert, Ashley E; Massat, Ben; Puissant, Madeleine M; Palygin, Oleg; Geurts, Aron M; Hodges, Matthew R

2016-05-01

Genetic deletion of brain serotonin (5-HT) neurons in mice leads to ventilatory deficits and increased neonatal mortality during development. However, it is unclear if the loss of the 5-HT neurons or the loss of the neurochemical 5-HT led to the observed physiologic deficits. Herein, we generated a mutant rat model with constitutive central nervous system (CNS) 5-HT depletion by mutation of the tryptophan hydroxylase 2 (Tph2) gene in dark agouti (DA(Tph2-/-)) rats. DA(Tph2-/-) rats lacked TPH immunoreactivity and brain 5-HT but retain dopa decarboxylase-expressing raphe neurons. Mutant rats were also smaller, had relatively high mortality (∼50%), and compared with controls had reduced room air ventilation and body temperatures at specific postnatal ages. In adult rats, breathing at rest and hypoxic and hypercapnic chemoreflexes were unaltered in adult male and female DA(Tph2-/-) rats. Body temperature was also maintained in adult DA(Tph2-/-) rats exposed to 4°C, indicating unaltered ventilatory and/or thermoregulatory control mechanisms. Finally, DA(Tph2-/-) rats treated with the 5-HT precursor 5-hydroxytryptophan (5-HTP) partially restored CNS 5-HT and showed increased ventilation (P < 0.05) at a developmental age when it was otherwise attenuated in the mutants. We conclude that constitutive CNS production of 5-HT is critically important to fundamental homeostatic control systems for breathing and temperature during postnatal development in the rat. Copyright © 2016 the American Physiological Society.

Chronic central serotonin depletion attenuates ventilation and body temperature in young but not adult Tph2 knockout rats

PubMed Central

Kaplan, Kara; Echert, Ashley E.; Massat, Ben; Puissant, Madeleine M.; Palygin, Oleg; Geurts, Aron M.

2016-01-01

Genetic deletion of brain serotonin (5-HT) neurons in mice leads to ventilatory deficits and increased neonatal mortality during development. However, it is unclear if the loss of the 5-HT neurons or the loss of the neurochemical 5-HT led to the observed physiologic deficits. Herein, we generated a mutant rat model with constitutive central nervous system (CNS) 5-HT depletion by mutation of the tryptophan hydroxylase 2 (Tph2) gene in dark agouti (DATph2−/−) rats. DATph2−/− rats lacked TPH immunoreactivity and brain 5-HT but retain dopa decarboxylase-expressing raphe neurons. Mutant rats were also smaller, had relatively high mortality (∼50%), and compared with controls had reduced room air ventilation and body temperatures at specific postnatal ages. In adult rats, breathing at rest and hypoxic and hypercapnic chemoreflexes were unaltered in adult male and female DATph2−/− rats. Body temperature was also maintained in adult DATph2−/− rats exposed to 4°C, indicating unaltered ventilatory and/or thermoregulatory control mechanisms. Finally, DATph2−/− rats treated with the 5-HT precursor 5-hydroxytryptophan (5-HTP) partially restored CNS 5-HT and showed increased ventilation (P < 0.05) at a developmental age when it was otherwise attenuated in the mutants. We conclude that constitutive CNS production of 5-HT is critically important to fundamental homeostatic control systems for breathing and temperature during postnatal development in the rat. PMID:26869713

Synthesis and evaluation of a series of 2-substituted-5-thiopropylpiperazine (piperidine)-1,3,4-oxadiazoles derivatives as atypical antipsychotics.

PubMed

Chen, Yin; Xu, Xiangqing; Liu, Xin; Yu, Minquan; Liu, Bi-Feng; Zhang, Guisen

2012-01-01

It is important to develop novel antipsychotics that can effectively treat schizophrenia with minor side-effects. The aim of our work is to develop novel antipsychotics that act on dopamine D(2) and D(3), serotonin 5-HT(1A) and 5-HT(2A) receptors with low affinity for the serotonin 5-HT(2C) and H(1) receptors, which can effectively cure positive symptoms, negative symptoms and cognitive impairment without the weight gain side-effect. A series of 2-substituted-5-thiopropylpiperazine (piperidine) -1,3,4-oxadiazoles derivatives have been synthesized and the target compounds were evaluated for binding affinities to D(2), 5-HT(1A) and 5-HT(2A) receptors. Preliminary results indicated that compounds 14, 16 and 22 exhibited high affinities to D(2), 5-HT(1A) and 5-HT(2A) receptors among these compounds. Further binding tests showed that compound 22 had high affinity for D(3) receptor, and low affinity for serotonin 5-HT(2C) and H(1) receptors. In addition, compound 22 inhibited apomorphine-induced climbing behavior and MK-801-induced hyperactivity with no extrapyramidal symptoms liability in mice. Moreover, compound 22 exhibited acceptable pharmacokinetic properties. Compound 22 showed an atypical antipsychotic activity without liability for extrapyramidal symptoms. We anticipate compound 22 to be useful for developing a novel class of drug for the treatment of schizophrenia.

Behavioral and Pharmacogenetics of Aggressive Behavior

PubMed Central

Takahashi, Aki; Quadros, Isabel M.; de Almeida, Rosa M. M.; Miczek, Klaus A.

2013-01-01

Serotonin (5-HT) has long been considered as a key transmitter in the neurocircuitry controlling aggression. Impaired regulation of each subtype of 5-HT receptor, 5-HT transporter, synthetic and metabolic enzymes has been linked particularly to impulsive aggression. The current summary focuses mostly on recent findings from pharmacological and genetic studies. The pharmacological treatments and genetic manipulations or polymorphisms of a specific target (e.g., 5-HT1A receptor) can often result in inconsistent results on aggression, due to “phasic” effects of pharmacological agents vs “trait”-like effects of genetic manipulations. Also, the local administration of a drug using the intracranial microinjection technique has shown that activation of specific subtypes of 5-HT receptors (5-HT1A and 5-HT1B) in mesocorticolimbic areas can reduce species-typical and other aggressive behaviors, but the same receptors in the medial prefrontal cortex or septal area promote escalated forms of aggression. Thus, there are receptor populations in specific brain regions that preferentially modulate specific types of aggression. Genetic studies have shown important gene × environment interactions; it is likely that the polymorphisms in the genes of 5-HT transporters (e.g., MAO A) or rate-limiting synthetic and metabolic enzymes of 5-HT determine the vulnerability to adverse environmental factors that escalate aggression. We also discuss the interaction between the 5-HT system and other systems. Modulation of 5-HT neurons in the dorsal raphe nucleus by GABA, glutamate, and CRF profoundly regulate aggressive behaviors. Also, interactions of the 5-HT system with other neuropeptides (arginine vasopressin, oxytocin, neuropeptide Y, opioid) have emerged as important neurobiological determinants of aggression. Studies of aggression in genetically modified mice identified several molecules that affect the 5-HT system directly (e.g., Tph2, 5-HT1B, 5-HT transporter, Pet1, MAOA) or indirectly (e.g. BDNF, nNOS, αCaMKII, Neuropeptide Y). The future agenda delineates specific receptor subpopulations for GABA, glutamate and neuropeptides as they modulate the canonical aminergic neurotransmitters in brainstem, limbic and cortical regions with the ultimate outcome of attenuating or escalating aggressive behavior. PMID:22297576

Antidepressant-like activity of VN2222, a serotonin reuptake inhibitor with high affinity at 5-HT1A receptors.

PubMed

Tordera, Rosa M; Monge, Antonio; Del Río, Joaquín; Lasheras, Berta

2002-05-03

It has been suggested that drugs combining serotonin (5-hydroxytryptamine, 5-HT) transporter blockade and 5-HT1A autoreceptor antagonism could be a novel strategy for a shorter onset of action and higher therapeutic efficacy of antidepressants. The present study was aimed at characterizing the pharmacology of 1-(3-benzo[b]tiophenyl)-3-[4-(2-methoxyphenyl)-1-piperazinyl]-1-propanol (VN2222) a new synthetic compound with high affinity at both the 5-HT transporter and 5-HT1A receptors and devoid of high affinity at other receptors studied, with the only exception of alpha1-adrenoceptors. In keeping with the binding affinity at the 5-HT transporter, VN2222 inhibited 5-HT uptake in vitro both in rat cortical synaptosomes and in mesencephalic cultures and also in vivo when administered locally into the rat ventral hippocampus. After systemic administration, VN2222 exhibited an inverted U-shape effect so the inhibition of [3H]5-HT uptake ex vivo and the increase in 5-HT extracellular levels in microdialysis experiments was observed at low doses of 0.01-0.1 mg/kg whereas higher doses were ineffective. In studies related to 5-HT1A receptor function, 0.01-0.1 microM VN2222 produced a partial inhibition of forskolin-stimulated cAMP formation behaving as a weak agonist of 5-HT1A receptors. In body temperature studies, 5 mg/kg VN2222 produced a mild hypothermic effect in mice, suggesting a weak agonist activity at presynaptic 5-HT1A receptors; much lower doses (0.01-0.5 mg/kg) partially antagonized the hypothermia induced by 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) possibly through 5-HT transporter blockade. In the learned helplessness test in rats, an animal model for antidepressants, 1-5 mg/kg VN2222 reduced significantly the number of escape failures. Consequently, VN2222 is a new compound with a dual effect on the serotonergic system, as 5-HT uptake blocker and 5-HT1A receptor partial agonist, and with a remarkable activity in an animal model of depression with high predictive validity.

5-HT(2C) receptor RNA editing in the amygdala of C57BL/6J, DBA/2J, and BALB/cJ mice.

PubMed

Hackler, Elizabeth A; Airey, David C; Shannon, Caitlin C; Sodhi, Monsheel S; Sanders-Bush, Elaine

2006-05-01

Post-transcriptional RNA editing of the G-protein coupled 5-hydroxytryptamine-2C (5-HT(2C)) receptor predicts an array of 24 receptor isoforms, some of which are characterized by reduced constitutive activity and potency to initiate intracellular signaling. The amygdala is integral to anxiety, fear, and related psychiatric diseases. Activation of 5-HT(2C) receptors within the amygdala is anxiogenic. Here, we describe the RNA editing profiles from amygdala of two inbred mouse strains (BALB/cJ and DBA/2J) known to be more anxious than a third (C57BL/6J). We confirmed the strain anxiety differences using light<-->dark exploration, and we discovered that BALB/cJ and DBA/2J are each characterized by a higher functioning RNA editing profile than C57BL/6J. BALB/cJ and DBA/2J exhibit a roughly two-fold reduction in C site editing, and a corresponding two-fold reduction in the edited isoform VSV. C57BL/6J is characterized by a relative decrease in the unedited highly functional isoform INI. We estimated the heritability of editing at the C site to be approximately 40%. By sequencing genomic DNA, we found complete conservation between C57BL/6J, BALB/cJ, DBA/2J and 37 other inbred strains for the RNA edited region of Htr2c, suggesting Htr2c DNA sequence does not influence variation in Htr2c RNA editing between inbred strains of mice. We did, however, discover that serotonin turnover is reduced in BALB/cJ and DBA/2J, consistent with emerging evidence that synaptic serotonin levels regulate RNA editing. These results encourage further study of the causes and consequences of 5-HT(2C) receptor RNA editing in the amygdala of mice.

Tolerance and cross-tolerance to head twitch behavior elicited by phenethylamine- and tryptamine-derived hallucinogens in mice.

PubMed

Smith, Douglas A; Bailey, Jessica M; Williams, Diarria; Fantegrossi, William E

2014-12-01

The serotonin 5-hydroxytryptamine 2A (5-HT2A) receptor is a potential therapeutic target to a host of neuropsychiatric conditions, but agonist actions at this site are linked to abuse-related hallucinogenic effects that may limit therapeutic efficacy of chronic drug administration. Tolerance to some effects of hallucinogens has been observed in humans and laboratory animals, but the understanding of tolerance and cross-tolerance between distinct structural classes of hallucinogens is limited. Here, we used the drug-elicited head twitch response (HTR) in mice to assess the development of tolerance and cross-tolerance with two phenethylamine-derived [DOI (2,5-dimethoxy-4-iodoamphetamine) and 2C-T-7 (2,5-dimethoxy-4-propylthiophenethylamine)] and two tryptamine-derived [DPT (N,N-dipropyltryptamine) and DIPT (N,N-diisopropyltryptamine)] drugs with agonist affinity for 5-HT2A receptors. Tolerance developed to HTR elicited by daily DOI or 2C-T-7, but not to HTR elicited by DPT or DIPT. DOI-elicited tolerance was not surmountable with dose, and a similar insurmountable cross-tolerance was evident when DOI-tolerant mice were tested with various doses of 2C-T-7 or DPT. These studies suggest that the use of phenethylamine-derived hallucinogens as therapeutic agents may be limited not only by their abuse potential, but also by the rapid development of tolerance that would likely be maintained even if a patient were switched to a different 5-HT2A agonist medication from a distinct structural class. However, these experiments also imply that tryptamine-derived hallucinogens might have a reduced potential for tolerance development, compared with phenethylamine-derived 5-HT2A agonists, and might therefore be more suitable for chronic administration in a therapeutic context. Copyright © 2014 by The American Society for Pharmacology and Experimental Therapeutics.

Return of the lysergamides. Part I: Analytical and behavioural characterization of 1-propionyl-d-lysergic acid diethylamide (1P-LSD).

PubMed

Brandt, Simon D; Kavanagh, Pierce V; Westphal, Folker; Stratford, Alexander; Elliott, Simon P; Hoang, Khoa; Wallach, Jason; Halberstadt, Adam L

2016-09-01

1-Propionyl-d-lysergic acid diethylamide hemitartrate (1P-LSD) has become available as a 'research chemical' in the form of blotters and powdered material. This non-controlled derivative of d-lysergic acid diethylamide (LSD) has previously not been described in the published literature despite being closely related to 1-acetyl-LSD (ALD-52), which was developed in the 1950s. This study describes the characterization of 1P-LSD in comparison with LSD using various chromatographic and mass spectrometric methods, infrared and nuclear magnetic resonance spectroscopy. An important feature common to LSD and other serotonergic hallucinogens is that they produce 5-HT2A -receptor activation and induce the head-twitch response (HTR) in rats and mice. In order to assess whether 1P-LSD displays LSD-like properties and activates the 5-HT2A receptor, male C57BL/6 J mice were injected with vehicle (saline) or 1P-LSD (0.025-0.8 mg/kg, IP) and HTR assessed for 30 min using magnetometer coil recordings. It was found that 1P-LSD produced a dose-dependent increase in HTR counts, and that it had ~38% (ED50  = 349.6 nmol/kg) of the potency of LSD (ED50  = 132.8 nmol/kg). Furthermore, HTR was abolished when 1P-LSD administration followed pretreatment with the selective 5-HT2A receptor antagonist M100907 (0.1 mg/kg, SC), which was consistent with the concept that the behavioural response was mediated by activation of the 5-HT2A receptor. These results indicate that 1P-LSD produces LSD-like effects in mice, consistent with its classification as a serotonergic hallucinogen. Nevertheless, the extent to which 1P-LSD might show psychoactive effects in humans similar to LSD remains to be investigated. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

Return of the lysergamides. Part I: Analytical and behavioral characterization of 1-propionyl-d-lysergic acid diethylamide (1P-LSD)

PubMed Central

Brandt, Simon D.; Kavanagh, Pierce V.; Westphal, Folker; Stratford, Alexander; Elliott, Simon P.; Hoang, Khoa; Wallach, Jason; Halberstadt, Adam L.

2015-01-01

1-Propionyl-d-lysergic acid diethylamide hemitartrate (1P-LSD) has become available as a ‘research chemical’ in form of blotters and powdered material. This non-controlled derivative of d-lysergic acid diethylamide (LSD) has previously not been described in the published literature despite being closely related to 1-acetyl-LSD (ALD-52), which was developed in the 1950s. This study describes the characterization of 1P-LSD in comparison with LSD using various chromatographic, mass spectrometric methods and nuclear magnetic resonance spectroscopy. An important feature common to LSD and other serotonergic hallucinogens is that they produce 5-HT2A-receptor activation and induce the head-twitch response (HTR) in rats and mice. In order to assess whether 1P-LSD displays LSD-like properties and activates the 5-HT2A receptor, male C57BL/6J mice were injected with vehicle (saline) or 1P-LSD (0.025–0.8 mg/kg, IP) and HTR assessed for 30 min using magnetometer coil recordings. It was found that 1P-LSD produced a dose-dependent increase in HTR counts, and that it had ~38% (ED50 = 349.6 nmol/kg) of the potency of LSD (ED50 = 132.8 nmol/kg). Furthermore, the HTR was abolished when 1P-LSD administration followed pre-treatment with the selective 5-HT2A receptor antagonist M100907 (0.1 mg/kg, SC), which confirms that the behavioral response is mediated by activation of the 5-HT2A receptor. These results indicate that 1P-LSD produces LSD-like effects in mice, consistent with its classification as a serotonergic hallucinogen. Nevertheless, the extent to which 1P-LSD might show psychoactive effects in humans similar to LSD remains to be investigated. PMID:26456305

The high-level expression of human tissue plasminogen activator in the milk of transgenic mice with hybrid gene locus strategy.

PubMed

Zhou, Yanrong; Lin, Yanli; Wu, Xiaojie; Xiong, Fuyin; Lv, Yuemeng; Zheng, Tao; Huang, Peitang; Chen, Hongxing

2012-02-01

Transgene expression for the mammary gland bioreactor aimed at producing recombinant proteins requires optimized expression vector construction. Previously we presented a hybrid gene locus strategy, which was originally tested with human lactoferrin (hLF) as target transgene, and an extremely high-level expression of rhLF ever been achieved as to 29.8 g/l in mice milk. Here to demonstrate the broad application of this strategy, another 38.4 kb mWAP-htPA hybrid gene locus was constructed, in which the 3-kb genomic coding sequence in the 24-kb mouse whey acidic protein (mWAP) gene locus was substituted by the 17.4-kb genomic coding sequence of human tissue plasminogen activator (htPA), exactly from the start codon to the end codon. Corresponding five transgenic mice lines were generated and the highest expression level of rhtPA in the milk attained as to 3.3 g/l. Our strategy will provide a universal way for the large-scale production of pharmaceutical proteins in the mammary gland of transgenic animals.

Serotonin Transporter-Independent Actions of the Antidepressant Vortioxetine As Revealed Using the SERT Met172 Mouse.

PubMed

Nackenoff, Alex G; Simmler, Linda D; Baganz, Nicole L; Pehrson, Alan L; Sánchez, Connie; Blakely, Randy D

2017-05-17

Selective serotonin (5-HT, SERT) reuptake inhibitors (SSRIs) are the most commonly prescribed treatments for depression. However, they have delayed efficacy and can induce side-effects that can encourage discontinuation. Recently, agents have been developed, including vortioxetine (Trintellix), that augment SERT blockade with interactions at other targets. At therapeutic doses, vortioxetine interacts with SERT as well as 5-HT 1A , 5-HT 1B , 5-HT 3 , and 5-HT 7 receptors. We assessed the SERT-dependency of vortioxetine action using the SERT Met172 mouse model, which disrupts high-affinity interactions of many antidepressants with the transporter. We demonstrate that the SERT Met172 substitution induces an ∼19-fold loss in vortioxetine potency for SERT inhibition in midbrain synaptosomes. Moreover, in these mice, we observed reduced SERT occupancy, a diminished ability to prolong 5-HT clearance, and a reduced capacity to elevate extracellular 5-HT. Despite reduced interactions with SERT, vortioxetine maintained its ability to enhance mobility in tail suspension and forced swim tests, reduce consumption latency in the novelty induced hypophagia test, and promoted proliferation and survival of subgranular zone hippocampal stem cells. Our findings suggest that the antidepressant actions of vortioxetine may be SERT-independent, and encourage consideration of agents that mimic one or more actions of the drug in the development of improved depression treatments.

Defective Response of Natural Killer Activity to Thyroxine in Graves’ Disease

PubMed Central

Lee, Myung-Shik; Hong, Weon-Seon; Hong, Seong Woon; Lee, Jhin-Oh; Kang, Tae-Woong

1990-01-01

The effect of thyroxine (T4) on natural killer (NK) activity of peripheral blood lymphocytes (PBL) was investigated, using a 4-hr 51Cr release assay, in 18 patients with previously untreated Graves’ disease and in 18 controls. NK activity in patients with Graves disease was not significantly different from that in the controls. Normal T4 (NT) and high T4 (HT) medium, free T4 concentrations in which were 1.01 and 16.3 ng/dl, respectively, were used to evaluate the effect of T4 on NK activity. In the controls, NK activity increased in the NT or HT medium compared with that in the control medium at effector to target cell (E : T) ratios of 25 : 1 and 50 : 1. NK activity in the Graves’ disease patients, however, did not increase when either the NT or HT medium was used at E : T ratios of 25 : 1 and 50 : 1. These results suggest that patients with Graves’ disease have a similar NK activity to the controls but have a defect in the peripheral blood lymphocytes to increase NK activity in response to T4. PMID:2098098

The Role of 5-HT3 Receptors in Signaling from Taste Buds to Nerves

PubMed Central

Vandenbeuch, Aurelie; Voigt, Anja; Meyerhof, Wolfgang; Kinnamon, Sue C.; Finger, Thomas E.

2015-01-01

Activation of taste buds triggers the release of several neurotransmitters, including ATP and serotonin (5-hydroxytryptamine; 5-HT). Type III taste cells release 5-HT directly in response to acidic (sour) stimuli and indirectly in response to bitter and sweet tasting stimuli. Although ATP is necessary for activation of nerve fibers for all taste stimuli, the role of 5-HT is unclear. We investigated whether gustatory afferents express functional 5-HT3 receptors and, if so, whether these receptors play a role in transmission of taste information from taste buds to nerves. In mice expressing GFP under the control of the 5-HT3A promoter, a subset of cells in the geniculate ganglion and nerve fibers in taste buds are GFP-positive. RT-PCR and in situ hybridization confirmed the presence of 5-HT3A mRNA in the geniculate ganglion. Functional studies show that only those geniculate ganglion cells expressing 5-HT3A-driven GFP respond to 10 μm 5-HT and this response is blocked by 1 μm ondansetron, a 5-HT3 antagonist, and mimicked by application of 10 μm m-chlorophenylbiguanide, a 5-HT3 agonist. Pharmacological blockade of 5-HT3 receptors in vivo or genetic deletion of the 5-HT3 receptors reduces taste nerve responses to acids and other taste stimuli compared with controls, but only when urethane was used as the anesthetic. We find that anesthetic levels of pentobarbital reduce taste nerve responses apparently by blocking the 5-HT3 receptors. Our results suggest that 5-HT released from type III cells activates gustatory nerve fibers via 5-HT3 receptors, accounting for a significant proportion of the neural taste response. SIGNIFICANCE STATEMENT Historically, serotonin (5-hydroxytryptamine; 5-HT) has been described as a candidate neurotransmitter in the gustatory system and recent studies show that type III taste receptor cells release 5-HT in response to various taste stimuli. In the present study, we demonstrate that a subset of gustatory sensory neurons express functional 5-HT3 receptors that play a significant role in the neurotransmission of taste information from taste buds to nerves. In addition, we show that the anesthetic pentobarbital, widely used in taste nerve recordings, blocks 5-HT3 signaling. Therefore, many conclusions drawn from those data need to be reexamined in light of this anesthetic effect. PMID:26631478

Comparative assessment of the effects of salinomycin and monensin on the biodistribution of lead and some essential metal ions in mice, subjected to subacute lead intoxication.

PubMed

Ivanova, Juliana; Gluhcheva, Yordanka; Dimova, Donika; Pavlova, Ekaterina; Arpadjan, Sonja

2016-01-01

In this study, we present a comparative assessment of the effects of two polyether ionophorous antibiotics (monensin and salinomycin) on the concentrations of lead (Pb), cooper (Cu), zinc (Zn) and iron (Fe) in the kidneys, spleen, liver and brain of Pb-intoxicated animals. Our data demonstrated that the intoxication of ICR male mice with Pb salt resulted in a significant accumulation of Pb in all studied organs of the mice compared to the untreated control animals. The biodistribution of the toxic metal was in the order kidneys>spleen>liver>brain. The treatment of the Pb-intoxicated animals with tetraethylammonium salts of monensic and salinomycinic acids significantly decreased the concentration of the toxic metal ion compared to the toxic control. The effect varied in the interval 38% (for kidneys) to 52% (for brain) compared to the toxic control group (Pb). The tetraethylammonium salt of salinomycinic acid was more effective in reducing the Pb concentration in the brain of the Pb-treated mice compared to monensin. Pb-intoxication did not affect significantly the Zn endogenous concentration compared to the normal values. The treatment of ICR male mice with Pb-salt decreased the Cu concentration in the spleen and increased the Cu concentration in the liver compared to the untreated control animals. The detoxification of the Pb-intoxicated mice with tetraethylammonium salts of salinomycinic and monensic acids restored the Cu concentration in the spleen, but did not affect the Cu levels in the liver. The Pb-intoxication of the ICR mice resulted in a significant decrease of the Fe-concentration in the spleen and liver compared to the untreated control animals. The administration of the tetraethylammonium salts of salinomycinic and monensic acids to the Pb-treated animals restored the levels of Fe in both organs. Copyright © 2015 Elsevier GmbH. All rights reserved.

Docosahexaenoyl serotonin emerges as most potent inhibitor of IL-17 and CCL-20 released by blood mononuclear cells from a series of N-acyl serotonins identified in human intestinal tissue.

PubMed

Wang, Ya; Balvers, Michiel G J; Hendriks, Henk F J; Wilpshaar, Tessa; van Heek, Tjarda; Witkamp, Renger F; Meijerink, Jocelijn

2017-09-01

Fatty acid amides (FAAs), conjugates of fatty acids with ethanolamine, mono-amine neurotransmitters or amino acids are a class of molecules that display diverse functional roles in different cells and tissues. Recently we reported that one of the serotonin-fatty acid conjugates, docosahexaenoyl serotonin (DHA-5-HT), previously found in gut tissue of mouse and pig, attenuates the IL-23-IL-17 signaling axis in LPS-stimulated mice macrophages. However, its presence and effects in humans remained to be elucidated. Here, we report for the first time its identification in human intestinal (colon) tissue, along with a series of related N-acyl serotonins. Furthermore, we tested these fatty acid conjugates for their ability to inhibit the release of IL-17 and CCL-20 by stimulated human peripheral blood mononuclear cells (PBMCs). Serotonin conjugates with palmitic acid (PA-5-HT), stearic acid (SA-5-HT) and oleic acid (OA-5-HT) were detected in higher levels than arachidonoyl serotonin (AA-5-HT) and DHA-5-HT, while eicosapentaenoyl serotonin (EPA-5-HT) could not be quantified. Among these, DHA-5-HT was the most potent in inhibiting IL-17 and CCL-20, typical Th17 pro-inflammatory mediators, by Concanavalin A (ConA)-stimulated human PBMCs. These results underline the idea that DHA-5-HT is a gut-specific endogenously produced mediator with the capacity to modulate the IL-17/Th17 signaling response. Our findings may be of relevance in relation to intestinal inflammatory diseases like Crohn's disease and Ulcerative colitis. Copyright © 2017. Published by Elsevier B.V.

Effects of combined treatment with mephedrone and methamphetamine or 3,4-methylenedioxymethamphetamine on serotonin nerve endings of the hippocampus

PubMed Central

Angoa-Pérez, Mariana; Kane, Michael J.; Herrera-Mundo, Nieves; Francescutti, Dina M.; Kuhn, Donald M.

2013-01-01

Aims Mephedrone is a stimulant drug of abuse with close structural and mechanistic similarities to methamphetamine and 3,4-methylenedioxymethamphetamine (MDMA). Although mephedrone does not damage dopamine nerve endings it increases the neurotoxicity of amphetamine, methamphetamine and MDMA. The effects of mephedrone on serotonin (5HT) nerve endings are not fully understood, with some investigators reporting damage while others conclude it does not. Presently, we investigate if mephedrone given alone or with methamphetamine or MDMA damages 5HT nerve endings of the hippocampus. Main methods The status of 5HT nerve endings in hippocampus of female C57BL mice was assessed through measures of 5HT by HPLC and by immunoblot analysis of serotonin transporter (SERT) and tryptophan hydroxylase 2 (TPH2), selective markers of 5HT nerve endings. Astrocytosis was assessed through measures of glial fibrillary acidic protein (GFAP) (immunoblotting) and microglial activation was determined by histochemical staining with Isolectin B4. Key findings Mephedrone alone did not cause persistent reductions in the levels of 5HT, SERT or TPH2. Methamphetamine and MDMA alone caused mild reductions in 5HT but did not change SERT and TPH2 levels. Combined treatment with mephedrone and methamphetamine or MDMA did not change the status of 5HT nerve endings to an extent that was different from either drug alone. Significance Mephedrone does not cause toxicity to 5HT nerve endings of the hippocampus. When co-administered with methamphetamine or MDMA, drugs that are often co-abused with mephedrone by humans, toxicity is not increased as is the case for dopamine nerve endings when these drugs are taken together. PMID:23892197

The role of adenosine A1 and A2A receptors in the caffeine effect on MDMA-induced DA and 5-HT release in the mouse striatum.

PubMed

Górska, A M; Gołembiowska, K

2015-04-01

3,4-Methylenedioxymethamphetamine (MDMA, "ecstasy") popular as a designer drug is often used with caffeine to gain a stronger stimulant effect. MDMA induces 5-HT and DA release by interaction with monoamine transporters. Co-administration of caffeine and MDMA may aggravate MDMA-induced toxic effects on DA and 5-HT terminals. In the present study, we determined whether caffeine influences DA and 5-HT release induced by MDMA. We also tried to find out if adenosine A1 and A2A receptors play a role in the effect of caffeine by investigating the effect of the selective adenosine A1 and A2A receptor antagonists, DPCPX and KW 6002 on DA and 5-HT release induced by MDMA. Mice were treated with caffeine (10 mg/kg) and MDMA (20 or 40 mg/kg) alone or in combination. DA and 5-HT release in the mouse striatum was measured using in vivo microdialysis. Caffeine exacerbated the effect of MDMA on DA and 5-HT release. DPCPX or KW 6002 co-administered with MDMA had similar influence as caffeine, but KW 6002 was more potent than caffeine or DPCPX. To exclude the contribution of MAO inhibition by caffeine in the caffeine effect on MDMA-induced increase in DA and 5-HT, we also tested the effect of the nonxanthine adenosine receptor antagonist CGS 15943A lacking properties of MAO activity modification. Our findings indicate that adenosine A1 and A2A receptor blockade may account for the caffeine-induced exacerbation of the MDMA effect on DA and 5-HT release and may aggravate MDMA toxicity.

The Role of 5-HT2A, 5-HT2C and mGlu2 Receptors in the Behavioral Effects of Tryptamine Hallucinogens N,N-Dimethyltryptamine and N,N-Diisopropyltryptamine in Rats and Mice

PubMed Central

Carbonaro, Theresa M.; Eshleman, Amy J.; Forster, Michael J.; Cheng, Kejun; Rice, Kenner C.; Gatch, Michael B.

2014-01-01

Rationale: Serotonin 5-HT2A and 5-HT2C receptors are thought to be the primary pharmacological mechanisms for serotonin-mediated hallucinogenic drugs, but recently there has been interest in metabotropic glutamate (mGluR2) receptors as contributors to the mechanism of hallucinogens. Objective: The present study assesses the role of these 5-HT and glutamate receptors as molecular targets for two tryptamine hallucinogens, N,N-dimethyltryptamine (DMT) and N,N-diisopropyltryptamine (DiPT). Methods: Drug discrimination, head twitch and radioligand binding assays were used. A 5-HT2AR inverse agonist (MDL100907), 5-HT2CR antagonist (SB242084) and mGluR2/3 agonist (LY379268) were tested for their ability to attenuate the discriminative stimulus effects of DMT and DiPT; an mGluR2/3 antagonist (LY341495) was tested for potentiation. MDL100907 was used to attenuate head twitches induced by DMT and DiPT. Radioligand binding studies and inosital-1-phosphate (IP-1) accumulation were performed at the 5-HT2CR for DiPT. Results: MDL100907 fully blocked the discriminative stimulus effects of DMT, but only partially blocked DiPT. SB242084 partially attenuated the discriminative stimulus effects of DiPT, but produced minimal attenuation of DMT’s effects. LY379268 produced potent, but only partial blockade of the discriminative stimulus effects of DMT. LY341495 facilitated DMT- and DiPT-like effects. Both compounds elicited head twitches (DiPT>DMT) which were blocked by MDL1000907. DiPT was a low potency full agonist at 5-HT2CR in vitro. Conclusions: The 5-HT2AR likely plays a major role in mediating the effects of both compounds. 5-HT2C and mGluR2 receptors likely modulate the discriminative stimulus effects of both compounds to some degree. PMID:24985890

The role of 5-HT2A, 5-HT 2C and mGlu2 receptors in the behavioral effects of tryptamine hallucinogens N,N-dimethyltryptamine and N,N-diisopropyltryptamine in rats and mice.

PubMed

Carbonaro, Theresa M; Eshleman, Amy J; Forster, Michael J; Cheng, Kejun; Rice, Kenner C; Gatch, Michael B

2015-01-01

Serotonin 5-HT2A and 5-HT2C receptors are thought to be the primary pharmacological mechanisms for serotonin-mediated hallucinogenic drugs, but recently there has been interest in metabotropic glutamate (mGluR2) receptors as contributors to the mechanism of hallucinogens. The present study assesses the role of these 5-HT and glutamate receptors as molecular targets for two tryptamine hallucinogens, N,N-dimethyltryptamine (DMT) and N,N-diisopropyltryptamine (DiPT). Drug discrimination, head twitch, and radioligand binding assays were used. A 5-HT2AR inverse agonist (MDL100907), 5-HT2CR antagonist (SB242084), and mGluR2/3 agonist (LY379268) were tested for their ability to attenuate the discriminative stimulus effects of DMT and DiPT; an mGluR2/3 antagonist (LY341495) was tested for potentiation. MDL100907 was used to attenuate head twitches induced by DMT and DiPT. Radioligand binding studies and inosital-1-phosphate (IP-1) accumulation were performed at the 5-HT2CR for DiPT. MDL100907 fully blocked the discriminative stimulus effects of DMT, but only partially blocked DiPT. SB242084 partially attenuated the discriminative stimulus effects of DiPT, but produced minimal attenuation of DMT's effects. LY379268 produced potent, but only partial blockade of the discriminative stimulus effects of DMT. LY341495 facilitated DMT- and DiPT-like effects. Both compounds elicited head twitches (DiPT>DMT) which were blocked by MDL1000907. DiPT was a low-potency full agonist at 5-HT2CR in vitro. The 5-HT2AR likely plays a major role in mediating the effects of both compounds. 5-HT2C and mGluR2 receptors likely modulate the discriminative stimulus effects of both compounds to some degree.

Portulaca oleracea extract can inhibit nodule formation of colon cancer stem cells by regulating gene expression of the Notch signal transduction pathway.

PubMed

Jin, Heiying; Chen, Li; Wang, Shuiming; Chao, Deng

2017-07-01

To investigate whether Portulaca oleracea extract affects tumor formation in colon cancer stem cells and its chemotherapy sensitivity. In addition, to analyze associated genetic changes within the Notch signal transduction pathway. Serum-free cultures of colon cancer cells (HT-29) and HT-29 cancer stem cells were treated with the chemotherapeutic drug 5-fluorouracil to assess sensitivity. Injections of the stem cells were also given to BALB/c mice to confirm tumor growth and note its characteristics. In addition, the effect of different concentrations of P. oleracea extract was tested on the growth of HT-29 colon cancer cells and HT-29 cancer stem cells, as determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method. The effects of P. oleracea extract on the expression of β-catenin, Notch1, and Notch2 in the HT-29 cells were studied using reverse transcription polymerase chain reaction and Western blotting. The tumor volume of the HT29 cells was two times larger than that of HT29 cancer stem cells. Treatment with P. oleracea extract inhibited the proliferation of both HT-29 cancer cells and HT-29 cancer stem cells at doses from 0.07 to 2.25 µg/mL. Apoptosis of HT-29 cancer cells and HT-29 cancer stem cells was assessed by flow cytometry; it was enhanced by the addition of P. oleracea extract. Finally, treatment with P. oleracea extract significantly downregulated the expression of the Notch1 and β-catenin genes in both cell types. The results of this study show that P. oleracea extract inhibits the growth of colon cancer stem cells in a dose-dependent manner. Furthermore, it inhibits the expression of the Notch1 and β-catenin genes. Taken together, this suggests that it may elicit its effects through regulatory and target genes that mediate the Notch signal transduction pathway.

A Novel Aminotetralin-Type Serotonin (5-HT) 2C Receptor-Specific Agonist and 5-HT2A Competitive Antagonist/5-HT2B Inverse Agonist with Preclinical Efficacy for Psychoses

PubMed Central

Morgan, Drake; Felsing, Daniel; Kondabolu, Krishnakanth; Rowland, Neil E.; Robertson, Kimberly L.; Sakhuja, Rajeev; Booth, Raymond G.

2014-01-01

Development of 5-HT2C agonists for treatment of neuropsychiatric disorders, including psychoses, substance abuse, and obesity, has been fraught with difficulties, because the vast majority of reported 5-HT2C selective agonists also activate 5-HT2A and/or 5-HT2B receptors, potentially causing hallucinations and/or cardiac valvulopathy. Herein is described a novel, potent, and efficacious human 5-HT2C receptor agonist, (−)-trans-(2S,4R)-4-(3′[meta]-bromophenyl)-N,N-dimethyl-1,2,3,4-tetrahydronaphthalen-2-amine (−)-MBP), that is a competitive antagonist and inverse agonist at human 5-HT2A and 5-HT2B receptors, respectively. (−)-MBP has efficacy comparable to the prototypical second-generation antipsychotic drug clozapine in three C57Bl/6 mouse models of drug-induced psychoses: the head-twitch response elicited by [2,5]-dimethoxy-4-iodoamphetamine; hyperlocomotion induced by MK-801 [(5R,10S)-(+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine hydrogen maleate (dizocilpine maleate)]; and hyperlocomotion induced by amphetamine. (−)-MBP, however, does not alter locomotion when administered alone, distinguishing it from clozapine, which suppresses locomotion. Finally, consumption of highly palatable food by mice was not increased by (−)-MBP at a dose that produced at least 50% maximal efficacy in the psychoses models. Compared with (−)-MBP, the enantiomer (+)-MBP was much less active across in vitro affinity and functional assays using mouse and human receptors and also translated in vivo with comparably lower potency and efficacy. Results indicate a 5-HT2C receptor-specific agonist, such as (−)-MBP, may be pharmacotherapeutic for psychoses, without liability for obesity, hallucinations, heart disease, sedation, or motoric disorders. PMID:24563531

Pharmacokinetics of endoxifen and tamoxifen in female mice: implications for comparative in vivo activity studies.

PubMed

Reid, Joel M; Goetz, Matthew P; Buhrow, Sarah A; Walden, Chad; Safgren, Stephanie L; Kuffel, Mary J; Reinicke, Kathryn E; Suman, Vera; Haluska, Paul; Hou, Xiaonan; Ames, Matthew M

2014-12-01

Reduced CYP2D6 metabolism and low Z-endoxifen (ENDX) concentrations may increase the risk of breast cancer recurrence in tamoxifen (TAM)-treated women. Little is known regarding the differences between TAM and ENDX murine pharmacokinetics or the effect of administration route on plasma concentrations of each drug. The pharmacokinetics of TAM and ENDX were characterized in female mice. For subcutaneous [s.c.] and oral TAM (4, 10 and 20 mg/kg), TAM AUC increased in a linear manner, but concentrations of the active metabolites [ENDX and 4-hydroxytamoxifen (4HT)] remained low. For oral TAM (20 mg), 4HT concentrations were tenfold greater (>25 ng/ml) than achievable in TAM-treated humans. Both oral (10-200 mg/kg) and s.c. (2.5-25 mg/kg) ENDX·HCl resulted in a greater than dose-proportional increase in AUC, with eightfold greater ENDX concentrations than an equivalent TAM dose. ENDX accumulated in plasma after 5-day dosing of 25 or 100 mg/kg ENDX·HCl and exceeded target concentrations of 0.1 and 1.0 μM, respectively, by twofold to fourfold. In murine models, oral ENDX yields substantially higher ENDX concentrations, compared to TAM. The low 4HT and ENDX concentrations observed in mice receiving s.c. TAM mirror the TAM pharmacokinetics in humans with impaired CYP2D6 metabolism. These data support the ongoing development of ENDX as a novel agent for the endocrine treatment of ER-positive breast cancer.

Antidepressant-Like Effects of Vaccinium bracteatum in Chronic Restraint Stress Mice: Functional Actions and Mechanism Explorations.

PubMed

Oh, Dool-Ri; Kim, Yujin; Choi, Eun-Jin; Jung, Myung-A; Oh, Kyo-Nyeo; Hong, Ji-Ae; Bae, Donghyuck; Kim, Kwangsu; Kang, Huwon; Kim, Jaeyong; Kim, Young Ran; Cho, Seung Sik; Choi, Chul-Young

2018-01-01

The fruit of Vaccinium bracteatum Thunb. (VBF) is commonly known as the oriental blueberry in Korea. The aim of this study was to evaluate the antidepressant-like effects of water VBF extract (VBFW) in a mouse model of chronic restraint stress (CRS) and to identify the underlying mechanisms of its action. The behavioral effects of VBFW were assessed in the forced swim test (FST) and open field test (OFT). The levels of serum corticosterone (CORT), brain monoamines, in addition to the extracellular signal-regulated kinases (ERKs)/protein kinase B (Akt) signaling pathway were evaluated. VBFW treatment significantly reduced the immobility time and increased swimming time in FST without altering the locomotor activity in unstressed mice. Furthermore, CRS mice treated with VBFW exhibited a significantly decreased immobility time in FST and serum CORT, increased locomotor activity in OFT, and enhanced brain monoamine neurotransmitters. Similarly, VBFW significantly upregulated the ERKs/Akt signaling pathway in the hippocampus and PFC. In addition, VBFW may reverse CORT-induced cell death by enhancing cyclic AMP-responsive element-binding protein expression through the up-regulation of ERKs/Akt signaling pathways. In addition, VBFW showed the strong antagonistic effect of the 5-HT[Formula: see text] receptor by inhibiting 5-HT-induced intracellular Ca[Formula: see text] and ERK1/2 phosphorylation. Our study provides evidence that antidepressant-like effects of VBFW might be mediated by the regulation of monoaminergic systems and glucocorticoids, which is possibly associated with neuroprotective effects and antagonism of 5-HT[Formula: see text] receptor.

Estrogen and progestogen use in postmenopausal women: July 2008 position statement of The North American Menopause Society

PubMed Central

2009-01-01

Objective To update for both clinicians and the lay public the evidence-based position statement published by The North American Menopause Society (NAMS) in March 2007 regarding its recommendations for menopausal hormone therapy (HT) for postmenopausal women, with consideration for the therapeutic benefit-risk ratio at various times through menopause and beyond. Design An Advisory Panel of clinicians and researchers expert in the field of women’s health was enlisted to review the March 2007 NAMS position statement, evaluate new evidence through an evidence-based analysis, and reach consensus on recommendations. The Panel’s recommendations were reviewed and approved by the NAMS Board of Trustees as an official NAMS position statement. The document was provided to other interested organizations to seek their endorsement. Results Current evidence supports a consensus regarding the role of HT in postmenopausal women, when potential therapeutic benefits and risks around the time of menopause are considered. This paper lists all these areas along with explanatory comments. Conclusions that vary from the 2007 position statement are highlighted. Addenda include a discussion of risk concepts, a new component not included in the 2007 paper, and a recommended list of areas for future HT research. A suggested reading list of key references is also provided. Conclusions Recent data support the initiation of HT around the time of menopause to treat menopause-related symptoms; to treat or reduce the risk of certain disorders, such as osteoporosis or fractures in select postmenopausal women; or both. The benefit-risk ratio for menopausal HT is favorable close to menopause but decreases with aging and with time since menopause in previously untreated women. PMID:18580541

Influence of short-term selenium supplementation on the natural course of Hashimoto's thyroiditis: clinical results of a blinded placebo-controlled randomized prospective trial.

PubMed

Esposito, D; Rotondi, M; Accardo, G; Vallone, G; Conzo, G; Docimo, G; Selvaggi, F; Cappelli, C; Chiovato, L; Giugliano, D; Pasquali, D

2017-01-01

The real efficacy of selenium supplementation in Hashimoto's thyroiditis (HT) is still an unresolved issue. We studied the short-term effect of L-selenomethionine on the thyroid function in euthyroid patients with HT. Our primary outcome measures were TSH, thyroid hormones, thyroid peroxidase antibody (TPOAb), thyroglobulin antibody (TGAb) levels and thyroid echogenicity after 6 months of L-selenomethionine treatment. The secondary outcome measure was serum CXCL10 levels. In a placebo-controlled randomized prospective study, we have enrolled untreated euthyroid patients with HT. Seventy-six patients were randomly assigned to receive L-selenomethionine 166 µg/die (SE n = 38) or placebo (controls n = 38) for 6 months. TSH, free T 4 (FT 4 ), free T 3 (FT 3 ), TPOAb and CXCL10 serum levels were assayed at time 0, after 3 and 6 months. An ultrasound examination of the left and right thyroid lobe in transverse and longitudinal sections was performed. A rectangular region, the region of interest, was selected for analysis. TSH, FT4, FT3, TPOAb, thyroid echogenicity and CXCL10 were not statistically different between SE and control groups at time 0, after 3 and 6 months. In the SE group, FT 4 levels were significantly decreased (P < 0.03) after 3 months, while FT 3 increased (P < 0.04) after 3 and 6 months versus baseline values. In the control group, the FT 3 decreased after 3 and 6 months (P < 0.02) compared to baseline. The short-term L-selenomethionine supplementation has a limited impact on the natural course in euthyroid HT. Our results tip the balance toward the ineffectiveness of short-term L-selenomethionine supplementation in HT.

Revisiting the Serotonin Hypothesis: Implications for Major Depressive Disorders.

PubMed

Fakhoury, Marc

2016-07-01

Major depressive disorder (MDD) is a heritable neuropsychiatric disease associated with severe changes at cellular and molecular levels. Its diagnosis mainly relies on the characterization of a wide range of symptoms including changes in mood and behavior. Despite the availability of antidepressant drugs, 10 to 30 % of patients fail to respond after a single or multiple treatments, and the recurrence of depression among responsive patients is very high. Evidence from the past decades suggests that the brain neurotransmitter serotonin (5-HT) is incriminated in MDD, and that a dysfunction of 5-HT receptors may play a role in the genesis of this disease. The 5-HT membrane transporter protein (SERT), which helps regulate the serotonergic transmission, is also implicated in MDD and is one of the main targets of antidepressant therapy. Although a number of behavioral tests and animal models have been developed to study depression, little is known about the neurobiological bases of MDD. Understanding the role of the serotonergic pathway will significantly help improve our knowledge of the pathophysiology of depression and may open up avenues for the development of new antidepressant drugs. The overarching goal of this review is to present recent findings from studies examining the serotonergic pathway in MDD, with a focus on SERT and the serotonin 1A (5-HT1A), serotonin 1B (5-HT1B), and serotonin 2A (5-HT2A) receptors. This paper also describes some of the main molecules involved in the internalization of 5-HT receptors and illustrates the changes in 5-HT neurotransmission in knockout mice and animal model of depression.

In the search for a lead structure among series of potent and selective hydantoin 5-HT7 R agents: The drug-likeness in vitro study.

PubMed

Latacz, Gniewomir; Lubelska, Annamaria; Jastrzębska-Więsek, Magdalena; Partyka, Anna; Sobiło, Andrzej; Olejarz, Agnieszka; Kucwaj-Brysz, Katarzyna; Satała, Grzegorz; Bojarski, Andrzej J; Wesołowska, Anna; Kieć-Kononowicz, Katarzyna; Handzlik, Jadwiga

2017-12-01

Since the year 1993, when 5-HT 7 receptor (5-HT 7 R) was discovered, there is no selective 5-HT 7 R ligand introduced to the pharmaceutical market. One out of the main reasons disqualifying the 5-HT 7 R ligands is weak drugability properties, including metabolic instability or low permeability. This study is focused on the search of a lead compound by "drug-likeness" estimation of the first series of selective and potent 5-HT 7 R ligands among 5-(4-fluorophenyl)-3-(2-hydroxy-3-(4-aryl-piperazin-1-yl)propyl)-5-methylimidazolidine-2,4-dione derivatives (11-16). The most important drugability parameters, i.e., permeability, metabolic stability, and safety, have been evaluated. The main metabolic pathways were determined. The forced swim test (FST) in mice was performed as a primary in vivo assay for compound 13 and the reference 2. The experiments showed promising drug-like properties for all ligands, with special attention to the benzhydryl (diphenylmethyl) derivative 13. The studies have also indicated in vivo activity of the compound 13 that was observed as a significant and specific antidepressant-like activity in the FST. Taking into account the beneficial properties of 13, i.e., good drug-like parameters, the significant antagonistic action, high selectivity to 5-HT 7 R, and its in vivo antidepressant-like activity, the compound should be considered as a new lead in the search for drugs acting on CNS via 5-HT 7 receptor. © 2017 John Wiley & Sons A/S.

Chemoprevention and therapy of mouse mammary carcinomas with doxorubicin encapsulated in sterically stabilized liposomes.

PubMed

Vaage, J; Donovan, D; Loftus, T; Abra, R; Working, P; Huang, A

1994-05-01

The objective of this study was to determine the ability of doxorubicin, encapsulated in sterically stabilized liposomes (Doxil [Liposome Technology, Inc., Menlo Park, CA]), to inhibit the spontaneous development of mammary carcinomas in mice. Monthly prophylactic intravenous injections of 6 mg/kg doses of Doxil were started when retired breeding C3H/He mice were 26 weeks old. Mice that developed a mammary carcinoma were then given weekly intravenous injections of 6 mg/kg doses to determine whether the tumors were susceptible or resistant to Doxil therapy. The monthly injections reduced the incidence of first mammary carcinomas in up to 88-week-old retired breeding C3H/He mice from 65 of 66 (98%) in untreated mice to 22 of 47 (47%) in treated mice. The first 15 mice that developed a mammary tumor while on the prophylactic protocol were then placed on a weekly therapeutic protocol. The therapeutic use of Doxil cured 3 of 15 mice and inhibited the growth of 12 tumors. Drug resistance as a result of treatments was not observed. The mean survival of tumor-bearing mice was extended from 24 days in untreated mice to 87 days in treated mice. Toxic side effects were limited to transient weight loss during the weekly Doxil treatments and to epidermal necrosis and dermal fibrosis due to drug extravasation at the sites of intravenous injections. The authors concluded that doxorubicin in sterically stabilized liposomes deserves to be explored further in comparative studies with free doxorubicin for the prophylaxis and therapy of mammary cancer.

cAMP Catalyzing Phosphodiesterases Control Cholinergic Muscular Activity But Their Inhibition Does Not Enhance 5-HT4 Receptor-Mediated Facilitation of Cholinergic Contractions in the Murine Gastrointestinal Tract

PubMed Central

Pauwelyn, Vicky; Lefebvre, Romain A.

2018-01-01

Background: As the signal transduction of 5-HT4 receptors on cholinergic neurons innervating smooth muscle is controlled by phosphodiesterase (PDE) 4 in porcine stomach and colon, and human large intestine, the in vivo gastroprokinetic effects of a 5-HT4 receptor agonist might be enhanced by combination with a selective PDE4 inhibitor. The presence of 5-HT4 receptors on cholinergic neurons towards murine gastrointestinal circular muscle was recently shown. If the control of this receptor pathway by PDE4 is also present in mice, this might be a good model for in vivo testing of the combination therapy. Therefore this study investigates the role of cAMP catalyzing PDEs in smooth muscle cell activity and in the intraneuronal signal transduction of the 5-HT4 receptors in the gastrointestinal tract of C57Bl/6J mice. Methods: In circular smooth muscle strips from murine fundus, jejunum, and colon, submaximal cholinergic contractions were induced by either electrical field stimulation (EFS) or by carbachol (muscarinic receptor agonist). The influence of the PDE inhibitors IBMX (non-selective), vinpocetine (PDE1), EHNA (PDE2), cilostamide (PDE3), and rolipram (PDE4) was tested on these contractions and on the facilitating effect of a submaximal concentration of prucalopride (5-HT4 receptor agonist) on EFS-induced contractions. Results: In the three gastrointestinal regions, IBMX and cilostamide concentration-dependently decreased carbachol- as well as EFS-induced contractions. Some inhibitory effect was also observed with rolipram. In the fundus a non-significant trend for an enhancement of the facilitating effect of prucalopride on EFS-induced contractions was observed with IBMX, but none of the selective PDE inhibitors enhanced the facilitating effect of prucalopride in fundus, jejunum or colon. Conclusion: In analogy with the porcine gastrointestinal tract, in murine fundus, jejunum, and colon circular smooth muscle PDE3 is the main regulator of the cAMP turnover, with some contribution of PDE4. In contrast to the porcine gastrointestinal tract, the in vitro facilitation of electrically induced cholinergic contractions by 5-HT4 receptor stimulation could not be enhanced by specific PDE inhibition. The C57Bl/6J murine model is thus not suitable for in vivo testing of a 5-HT4 receptor agonist combined with a selective PDE4 inhibitor. PMID:29568269

The first childhood case with coexisting Hashimoto thyroiditis, vitiligo and autoimmune hepatitis.

PubMed

Keskin, Melikşah; Savaş-Erdeve, Şenay; Özbay-Hoşnut, Ferda; Kurnaz, Erdal; Çetinkaya, Semra; Aycan, Zehra

2016-01-01

Hashimoto thyroiditis (HT) is the most common pediatric autoimmune endocrine disorder. It results in autoimmune-mediated thyroid gland destruction and is an organ-specific, typical autoimmune disease. The presence of antithyroid antibodies and the typical pattern on ultrasonography indicate the diagnosis. It is also frequently seen together with other autoimmune disorders including type 1 insulin-dependent diabetes, celiac disease, alopecia and vitiligo. Autoimmune hepatitis (AIH) is a chronic type of liver injury with an immune etiology that can frequently cause end-stage liver disease if left untreated. Autoimmune hepatitis patients may present with hepatitis, and the laboratory tests in the absence of other etiology usually reveal a positive immune serology together with elevated immunoglobulins and abnormal liver histology. It is interesting that HT and AIH are rarely seen together although both have an autoimmune etiology. 14-year-old male who was being followed-up for vitiligo presented with symptoms of a swelling at the neck and fatigue. He was diagnosed with HT after the tests and the liver enzymes were found to be high. The patient was also diagnosed with AIH after tests revealed that the liver enzyme elevation had continued for longer than six months. The thyroid functions and liver enzymes returned to normal and the symptoms decreased after sodium L-thyroxine replacement together with steroid and azathioprine treatment. We present this case as we believe it is the first pediatric patient diagnosed with HT, AIH and vitiligo.

Impact of serotonin 2C receptor null mutation on physiology and behavior associated with nigrostriatal dopamine pathway function.

PubMed

Abdallah, Luna; Bonasera, Stephen J; Hopf, F Woodward; O'Dell, Laura; Giorgetti, Marco; Jongsma, Minke; Carra, Scott; Pierucci, Massimo; Di Giovanni, Giuseppe; Esposito, Ennio; Parsons, Loren H; Bonci, Antonello; Tecott, Laurence H

2009-06-24

The impact of serotonergic neurotransmission on brain dopaminergic pathways has substantial relevance to many neuropsychiatric disorders. A particularly prominent role has been ascribed to the inhibitory effects of serotonin 2C receptor (5-HT(2C)R) activation on physiology and behavior mediated by the mesolimbic dopaminergic pathway, particularly in the terminal region of the nucleus accumbens. The influence of this receptor subtype on functions mediated by the nigrostriatal dopaminergic pathway is less clear. Here we report that a null mutation eliminating expression of 5-HT(2C)Rs produces marked alterations in the activity and functional output of this pathway. 5-HT(2C)R mutant mice displayed increased activity of substantia nigra pars compacta (SNc) dopaminergic neurons, elevated baseline extracellular dopamine concentrations in the dorsal striatum (DSt), alterations in grooming behavior, and enhanced sensitivity to the stereotypic behavioral effects of d-amphetamine and GBR 12909. These psychostimulant responses occurred in the absence of phenotypic differences in drug-induced extracellular dopamine concentration, suggesting a phenotypic alteration in behavioral responses to released dopamine. This was further suggested by enhanced behavioral responses of mutant mice to the D(1) receptor agonist SKF 81297. Differences in DSt D(1) or D(2) receptor expression were not found, nor were differences in medium spiny neuron firing patterns or intrinsic membrane properties following dopamine stimulation. We conclude that 5-HT(2C)Rs regulate nigrostriatal dopaminergic activity and function both at SNc dopaminergic neurons and at a locus downstream of the DSt.

The role of 5-HT1A receptors in the anti-aversive effects of cannabidiol on panic attack-like behaviors evoked in the presence of the wild snake Epicrates cenchria crassus (Reptilia, Boidae).

PubMed

Twardowschy, André; Castiblanco-Urbina, Maria Angélica; Uribe-Mariño, Andres; Biagioni, Audrey Francisco; Salgado-Rohner, Carlos José; Crippa, José Alexandre de Souza; Coimbra, Norberto Cysne

2013-12-01

The potential anxiolytic and antipanic properties of cannabidiol have been shown; however, its mechanism of action seems to recruit other receptors than those involved in the endocannabinoid-mediated system. It was recently shown that the model of panic-like behaviors elicited by the encounters between mice and snakes is a good tool to investigate innate fear-related responses, and cannabidiol causes a panicolytic-like effect in this model. The aim of the present study was to investigate the 5-hydroxytryptamine (5-HT) co-participation in the panicolytic-like effects of cannabidiol on the innate fear-related behaviors evoked by a prey versus predator interaction-based paradigm. Male Swiss mice were treated with intraperitoneal (i.p.) administrations of cannabidiol (3 mg/kg, i.p.) and its vehicle and the effects of the peripheral pre-treatment with increasing doses of the 5-HT1A receptor antagonist WAY-100635 (0.1, 0.3 and 0.9 mg/kg, i.p.) on instinctive fear-induced responses evoked by the presence of a wild snake were evaluated. The present results showed that the panicolytic-like effects of cannabidiol were blocked by the pre-treatment with WAY-100635 at different doses. These findings demonstrate that cannabidiol modulates the defensive behaviors evoked by the presence of threatening stimuli, and the effects of cannabidiol are at least partially dependent on the recruitment of 5-HT1A receptors.

Serotonergic system antagonists target breast tumor initiating cells and synergize with chemotherapy to shrink human breast tumor xenografts

PubMed Central

Gwynne, William D; Hallett, Robin M; Girgis-Gabardo, Adele; Bojovic, Bojana; Dvorkin-Gheva, Anna; Aarts, Craig; Dias, Kay; Bane, Anita; Hassell, John A

2017-01-01

Breast tumors comprise an infrequent tumor cell population, termed breast tumor initiating cells (BTIC), which sustain tumor growth, seed metastases and resist cytotoxic therapies. Hence therapies are needed to target BTIC to provide more durable breast cancer remissions than are currently achieved. We previously reported that serotonergic system antagonists abrogated the activity of mouse BTIC resident in the mammary tumors of a HER2-overexpressing model of breast cancer. Here we report that antagonists of serotonin (5-hydroxytryptamine; 5-HT) biosynthesis and activity, including US Federal Food and Drug Administration (FDA)-approved antidepressants, targeted BTIC resident in numerous breast tumor cell lines regardless of their clinical or molecular subtype. Notably, inhibitors of tryptophan hydroxylase 1 (TPH1), required for 5-HT biosynthesis in select non-neuronal cells, the serotonin reuptake transporter (SERT) and several 5-HT receptors compromised BTIC activity as assessed by functional sphere-forming assays. Consistent with these findings, human breast tumor cells express TPH1, 5-HT and SERT independent of their molecular or clinical subtype. Exposure of breast tumor cells ex vivo to sertraline (Zoloft), a selective serotonin reuptake inhibitor (SSRI), reduced BTIC frequency as determined by transplanting drug-treated tumor cells into immune-compromised mice. Moreover, another SSRI (vilazodone; Viibryd) synergized with chemotherapy to shrink breast tumor xenografts in immune-compromised mice by inhibiting tumor cell proliferation and inducing their apoptosis. Collectively our data suggest that antidepressants in combination with cytotoxic anticancer therapies may be an appropriate treatment regimen for testing in clinical trials. PMID:28404880

Serotonergic system antagonists target breast tumor initiating cells and synergize with chemotherapy to shrink human breast tumor xenografts.

PubMed

Gwynne, William D; Hallett, Robin M; Girgis-Gabardo, Adele; Bojovic, Bojana; Dvorkin-Gheva, Anna; Aarts, Craig; Dias, Kay; Bane, Anita; Hassell, John A

2017-05-09

Breast tumors comprise an infrequent tumor cell population, termed breast tumor initiating cells (BTIC), which sustain tumor growth, seed metastases and resist cytotoxic therapies. Hence therapies are needed to target BTIC to provide more durable breast cancer remissions than are currently achieved. We previously reported that serotonergic system antagonists abrogated the activity of mouse BTIC resident in the mammary tumors of a HER2-overexpressing model of breast cancer. Here we report that antagonists of serotonin (5-hydroxytryptamine; 5-HT) biosynthesis and activity, including US Federal Food and Drug Administration (FDA)-approved antidepressants, targeted BTIC resident in numerous breast tumor cell lines regardless of their clinical or molecular subtype. Notably, inhibitors of tryptophan hydroxylase 1 (TPH1), required for 5-HT biosynthesis in select non-neuronal cells, the serotonin reuptake transporter (SERT) and several 5-HT receptors compromised BTIC activity as assessed by functional sphere-forming assays. Consistent with these findings, human breast tumor cells express TPH1, 5-HT and SERT independent of their molecular or clinical subtype. Exposure of breast tumor cells ex vivo to sertraline (Zoloft), a selective serotonin reuptake inhibitor (SSRI), reduced BTIC frequency as determined by transplanting drug-treated tumor cells into immune-compromised mice. Moreover, another SSRI (vilazodone; Viibryd) synergized with chemotherapy to shrink breast tumor xenografts in immune-compromised mice by inhibiting tumor cell proliferation and inducing their apoptosis. Collectively our data suggest that antidepressants in combination with cytotoxic anticancer therapies may be an appropriate treatment regimen for testing in clinical trials.

Pharmacological Stimulation of the Brain Serotonin Receptor 7 as a Novel Therapeutic Approach for Rett Syndrome

PubMed Central

De Filippis, Bianca; Nativio, Paola; Fabbri, Alessia; Ricceri, Laura; Adriani, Walter; Lacivita, Enza; Leopoldo, Marcello; Passarelli, Francesca; Fuso, Andrea; Laviola, Giovanni

2014-01-01

Rett syndrome (RTT) is a rare neurodevelopmental disorder, characterized by severe behavioral and physiological symptoms. Mutations in the methyl CpG-binding protein 2 gene (MECP2) cause >95% of classic cases, and currently there is no cure for this devastating disorder. The serotonin receptor 7 (5-HT7R) is linked to neuro-physiological regulation of circadian rhythm, mood, cognition, and synaptic plasticity. We presently report that 5-HT7R density is consistently reduced in cortical and hippocampal brain areas of symptomatic MeCP2–308 male mice, a RTT model. Systemic repeated treatment with LP-211 (0.25 mg/kg once/day for 7 days), a brain-penetrant selective 5-HT7R agonist, was able to rescue RTT-related defective performance: anxiety-related profiles in a Light/Dark test, motor abilities in a Dowel test, the exploratory behavior in the Marble Burying test, as well as memory in the Novelty Preference task. In the brain of RTT mice, LP-211 also reversed the abnormal activation of PAK and cofilin (key regulators of actin cytoskeleton dynamics) and of the ribosomal protein (rp) S6, whose reduced activation in MECP2 mutant neurons by mTOR is responsible for the altered protein translational control. Present findings indicate that pharmacological targeting of 5-HT7R improves specific behavioral and molecular manifestations of RTT, thus representing a first step toward the validation of an innovative systemic treatment. Beyond RTT, the latter might be extended to other disorders associated with intellectual disability. PMID:24809912

A serotonin and melanocortin circuit mediates D-fenfluramine anorexia.

PubMed

Xu, Yong; Jones, Juli E; Lauzon, Danielle A; Anderson, Jason G; Balthasar, Nina; Heisler, Lora K; Zinn, Andrew R; Lowell, Bradford B; Elmquist, Joel K

2010-11-03

D-Fenfluramine (D-Fen) increases serotonin (5-HT) content in the synaptic cleft and exerts anorexigenic effects in animals and humans. However, the neural circuits that mediate these effects are not fully identified. To address this issue, we assessed the efficacy of D-Fen-induced hypophagia in mouse models with manipulations of several genes in selective populations of neurons. Expectedly, we found that global deletion of 5-HT 2C receptors (5-HT(2C)Rs) significantly attenuated D-Fen-induced anorexia. These anorexigenic effects were restored in mice with 5-HT(2C)Rs expressed only in pro-opiomelanocortin (POMC) neurons. Further, we found that deletion of melanocortin 4 receptors (MC4Rs), a downstream target of POMC neurons, abolished anorexigenic effects of D-Fen. Reexpression of MC4Rs only in SIM1 neurons in the hypothalamic paraventricular nucleus and neurons in the amygdala was sufficient to restore the hypophagic property of D-Fen. Thus, our results identify a neurochemically defined neural circuit through which D-Fen influences appetite and thereby indicate that this 5-HT(2C)R/POMC-MC4R/SIM1 circuit may yield a more refined target to exploit for weight loss.

A Serotonin and Melanocortin Circuit Mediates d-Fenfluramine Anorexia

PubMed Central

Xu, Yong; Jones, Juli E.; Lauzon, Danielle A.; Anderson, Jason G.; Balthasar, Nina; Heisler, Lora K.; Zinn, Andrew R.; Lowell, Bradford B.; Elmquist, Joel K.

2012-01-01

d-Fenfluramine (d-Fen) increases serotonin (5-HT) content in the synaptic cleft and exerts anorexigenic effects in animals and humans. However, the neural circuits that mediate these effects are not fully identified. To address this issue, we assessed the efficacy of d-Fen-induced hypophagia in mouse models with manipulations of several genes in selective populations of neurons. Expectedly, we found that global deletion of 5-HT 2C receptors (5-HT2CRs) significantly attenuated d-Fen-induced anorexia. These anorexigenic effects were restored in mice with 5-HT2CRs expressed only in pro-opiomelanocortin (POMC) neurons. Further, we found that deletion of melanocortin 4 receptors (MC4Rs), a downstream target of POMC neurons, abolished anorexigenic effects of d-Fen. Reexpression of MC4Rs only in SIM1 neurons in the hypothalamic paraventricular nucleus and neurons in the amygdala was sufficient to restore the hypophagic property of d-Fen. Thus, our results identify a neurochemically defined neural circuit through which d-Fen influences appetite and thereby indicate that this 5-HT2CR/POMC-MC4R/SIM1 circuit may yield a more refined target to exploit for weight loss. PMID:21048120

A new fluorescence/PET probe for targeting intracellular human telomerase reverse transcriptase (hTERT) using Tat peptide-conjugated IgM

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jung, Kyung oh; Biomedical Sciences, Seoul National University College of Medicine; Cancer Research Institute, Seoul National University College of Medicine

Despite an increasing need for methods to visualize intracellular proteins in vivo, the majority of antibody-based imaging methods available can only detect membrane proteins. The human telomerase reverse transcriptase (hTERT) is an intracellular target of great interest because of its high expression in several types of cancer. In this study, we developed a new probe for hTERT using the Tat peptide. An hTERT antibody (IgG or IgM) was conjugated with the Tat peptide, a fluorescence dye and {sup 64}Cu. HT29 (hTERT+) and U2OS (hTERT−) were used to visualize the intracellular hTERT. The hTERT was detected by RT-PCR and western blot. Fluorescencemore » signals for hTERT were obtained by confocal microscopy, live cell imaging, and analyzed by Tissue-FAXS. In nude mice, tumors were visualized using the fluorescence imaging devices Maestro™ and PETBOX. In RT-PCR and western blot, the expression of hTERT was detected in HT29 cells, but not in U2OS cells. Fluorescence signals were clearly observed in HT29 cells and in U2OS cells after 1 h of treatment, but signals were only detected in HT29 cells after 24 h. Confocal microscopy showed that 9.65% of U2OS and 78.54% of HT29 cells had positive hTERT signals. 3D animation images showed that the probe could target intranuclear hTERT in the nucleus. In mice models, fluorescence and PET imaging showed that hTERT in HT29 tumors could be efficiently visualized. In summary, we developed a new method to visualize intracellular and intranuclear proteins both in vitro and in vivo. - Highlights: • We developed new probes for imaging hTERT using Tat-conjugated IgM antibodies labeled with a fluorescent dye and radioisotope. • This probes could be used to overcome limitation of conventional antibody imaging system in live cell imaging. • This system could be applicable to monitor intracellular and intranuclear proteins in vitro and in vivo.« less

The antidepressant-like effect of 7-fluoro-1,3-diphenylisoquinoline-1-amine in the mouse forced swimming test is mediated by serotonergic and dopaminergic systems.

PubMed

Pesarico, Ana Paula; Sampaio, Tuane Bazanella; Stangherlin, Eluza Curte; Mantovani, Anderson C; Zeni, Gilson; Nogueira, Cristina Wayne

2014-10-03

The aim of the present study was to investigate the role of monoaminergic system in the antidepressant-like action of 7-fluoro-1,3-diphenylisoquinoline-1-amine (FDPI), a derivative of isoquinoline class, in Swiss mice. The antidepressant-like effect of FDPI was characterized in the modified forced swimming test (FST) and the possible mechanism of action was investigated by using serotonergic, dopaminergic and noradrenergic antagonists. Monoamine oxidase (MAO) activity and [(3)H]serotonin (5-HT) uptake were determined in prefrontal cortices of mice. The results showed that FDPI (1, 10 and 20mg/kg, i.g.) reduced the immobility time and increased the swimming time but did not alter climbing time in the modified FST. These effects were similar to those of paroxetine (8mg/kg, i.p.), a positive control. Pretreatments with p-chlorophenylalanine (100mg/kg, i.p., an inhibitor of 5-HT synthesis), WAY100635 (0.1mg/kg, s.c., 5-HT1A antagonist), ondansetron (1mg/kg, i.p., a 5-HT3 receptor antagonist), haloperidol (0.2mg/kg, i.p., a non-selective D2 receptor antagonist) and SCH23390 (0.05mg/kg, s.c., a D1 receptor antagonist) were effective to block the antidepressant-like effect of FDPI at a dose of 1mg/kg in the FST. Ritanserin (1mg/kg, i.p., a 5-HT2A/2C receptor antagonist), sulpiride (50mg/kg, i.p., a D2 and D3 receptor antagonist), prazosin (1mg/kg, i.p., an α1 receptor antagonist), yohimbine (1mg/kg, i.p., an α2 receptor antagonist) and propranolol (2mg/kg, i.p., a β receptor antagonist) did not modify the effect of FDPI in the FST. FDPI did not change synaptosomal [(3)H]5-HT uptake. At doses of 10 and 20mg/kg FDPI inhibited MAO-A and MAO-B activities. These results suggest that antidepressant-like effect of FDPI is mediated mostly by serotonergic and dopaminergic systems. Copyright © 2014 Elsevier Inc. All rights reserved.

5-HT1A receptor antagonists reduce food intake and body weight by reducing total meals with no conditioned taste aversion.

PubMed

Dill, M Joelle; Shaw, Janice; Cramer, Jeff; Sindelar, Dana K

2013-11-01

Serotonin acts through receptors controlling several physiological functions, including energy homeostasis regulation and food intake. Recent experiments demonstrated that 5-HT1A receptor antagonists reduce food intake. We sought to examine the microstructure of feeding with 5-HT1A receptor antagonists using a food intake monitoring system. We also examined the relationship between food intake, inhibition of binding and pharmacokinetic (PK) profiles of the antagonists. Ex vivo binding revealed that, at doses used in this study to reduce food intake, inhibition of binding of a 5-HT1A agonist by ~40% was reached in diet-induced obese (DIO) mice with a trend for higher binding in DIO vs. lean animals. Additionally, PK analysis detected levels from 2 to 24h post-compound administration. Male DIO mice were administered 5-HT1A receptor antagonists LY439934 (10 or 30 mg/kg, p.o.), WAY100635 (3 or 10mg/kg, s.c.), SRA-333 (10 or 30 mg/kg, p.o.), or NAD-299 (3 or 10mg/kg, s.c.) for 3 days and meal patterns were measured. Analyses revealed that for each antagonist, 24-h food intake was reduced through a specific decrease in the total number of meals. Compared to controls, meal number was decreased 14-35% in the high dose. Average meal size was not changed by any of the compounds. The reduction in food intake reduced body weight 1-4% compared to Vehicle controls. Subsequently, a conditioned taste aversion (CTA) assay was used to determine whether the feeding decrease might be an indicator of aversion, nausea, or visceral illness caused by the antagonists. Using a two bottle preference test, it was found that none of the compounds produced a CTA. The decrease in food intake does not appear to be a response to nausea or malaise. These results indicate that 5-HT1A receptor antagonist suppresses feeding, specifically by decreasing the number of meals, and induce weight loss without an aversive side effect. © 2013 Elsevier Inc. All rights reserved.

Immune Dysfunctions and Abrogation of the Inflammatory Response by Environmental Chemicals.

DTIC Science & Technology

1981-08-01

vitro effects in cats, mice, and humans. Materials and Methods: Animals: Mice: Young adult Swiss outbred mice and C57BL/6 (for skin graft donors) were...was used to determine significant differences between control (untreated) and MNU-treated cell cultures or animal groups. Results: Skin grafts : The...MNU-treated mice showed a dose-related increase in skin graft retention time, which was significant at 25 and 50 mg/kg MNU (p<.001). This is compared

No effect of C1473G polymorphism in the tryptophan hydroxylase 2 gene on the response of the brain serotonin system to chronic fluoxetine treatment in mice.

PubMed

Bazhenova, Ekaterina Y; Sinyakova, Nadezhda A; Kulikova, Elizabeth A; Kazarinova, Irina A; Bazovkina, Daria V; Gainetdinov, Raul R; Kulikov, Alexander V

2017-07-13

Selective serotonin reuptake inhibitors (SSRIs) are antidepressants that block serotonin transporter (SERT) and increase serotonin (5-HT) level in the synaptic cleft. The interaction between SERT and the key enzyme of 5-HT synthesis in the brain, tryptophan hydroxylase 2 (TPH2), is essential to maintain the brain 5-HT level. The G allele of C1473G polymorphism in Tph2 gene decreases enzyme activity by half in mouse brain. Here we studied effect of C1473G polymorphism on the reaction of brain 5-HT system to chronic fluoxetine treatment (120mg/l in drinking water, for 3 weeks) in adult males of the congenic B6-1473C and B6-1473G mouse lines with high and low enzyme activity, respectively. The polymorphism did not affect the levels of 5-HT, its metabolite, 5-hydroxyindoleacetic acid (5-HIAA) and Tph2 gene mRNA in the brain. Fluoxetine significantly attenuated 5-HT levels in the cortex and striatum, 5-HIAA concentrations in the cortex, hippocampus, striatum and midbrain, and Tph2 gene expression in the midbrain. However, we did not observed any effect of the genotype x treatment interaction on these neurochemical characteristics. Therefore, C1473G polymorphism does not seem to play an essential role in the reaction of the brain 5-HT system to chronic fluoxetine treatment. Copyright © 2017 Elsevier B.V. All rights reserved.

Chronic cannabis promotes pro-hallucinogenic signaling of 5-HT2A receptors through Akt/mTOR pathway.

PubMed

Ibarra-Lecue, Inés; Mollinedo-Gajate, Irene; Meana, J Javier; Callado, Luis F; Diez-Alarcia, Rebeca; Urigüen, Leyre

2018-04-27

Long-term use of potent cannabis during adolescence increases the risk of developing schizophrenia later in life, but to date, the mechanisms involved remain unknown. Several findings suggest that the functional selectivity of serotonin 2A receptor (5-HT2AR) through inhibitory G-proteins is involved in the molecular mechanisms responsible for psychotic symptoms. Moreover, this receptor is dysregulated in the frontal cortex of schizophrenia patients. In this context, studies involving cannabis exposure and 5-HT2AR are scarce. Here, we tested in mice the effect of an early chronic Δ 9 -tetrahydrocannabinol (THC) exposure on cortical 5-HT2AR expression, as well as on its in vivo and in vitro functionality. Long-term exposure to THC induced a pro-hallucinogenic molecular conformation of the 5-HT2AR and exacerbated schizophrenia-like responses, such as prepulse inhibition disruption. Supersensitive coupling of 5-HT2AR toward inhibitory Gαi1-, Gαi3-, Gαo-, and Gαz-proteins after chronic THC exposure was observed, without changes in the canonical Gαq/11-protein pathway. In addition, we found that inhibition of Akt/mTOR pathway by rapamycin blocks the changes in 5-HT2AR signaling pattern and the supersensitivity to schizophrenia-like effects induced by chronic THC. The present study provides the first evidence of a mechanistic explanation for the relationship between chronic cannabis exposure in early life and increased risk of developing psychosis-like behaviors in adulthood.

Curcumin-loaded embryonic stem cell exosomes restored neurovascular unit following ischemia-reperfusion injury.

PubMed

Kalani, Anuradha; Chaturvedi, Pankaj; Kamat, Pradip K; Maldonado, Claudio; Bauer, Philip; Joshua, Irving G; Tyagi, Suresh C; Tyagi, Neetu

2016-10-01

We tested whether the combined nano-formulation, prepared with curcumin (anti-inflammatory and neuroprotective molecule) and embryonic stem cell exosomes (MESC-exo cur ), restored neurovascular loss following an ischemia reperfusion (IR) injury in mice. IR-injury was created in 8-10 weeks old mice and divided into two groups. Out of two IR-injured groups, one group received intranasal administration of MESC-exo cur for 7days. Similarly, two sham groups were made and one group received MESC-exo cur treatment. The study determined that MESC-exo cur treatment reduced neurological score, infarct volume and edema following IR-injury. As compared to untreated IR group, MESC-exo cur treated-IR group showed reduced inflammation and N-methyl-d-aspartate receptor expression. Treatment of MESC-exo cur also reduced astrocytic GFAP expression and alleviated the expression of NeuN positive neurons in IR-injured mice. In addition, MESC-exo cur treatment restored vascular endothelial tight (claudin-5 and occludin) and adherent (VE-cadherin) junction proteins in IR-injured mice as compared to untreated IR-injured mice. These results suggest that combining the potentials of embryonic stem cell exosomes and curcumin can help neurovascular restoration following ischemia-reperfusion injury in mice. Copyright © 2016 Elsevier Ltd. All rights reserved.

Brain Histamine Is Crucial for Selective Serotonin Reuptake Inhibitors‘ Behavioral and Neurochemical Effects

PubMed Central

Munari, Leonardo; Provensi, Gustavo; Passani, Maria Beatrice; Galeotti, Nicoletta; Cassano, Tommaso; Benetti, Fernando; Corradetti, Renato

2015-01-01

Backgound: The neurobiological changes underlying depression resistant to treatments remain poorly understood, and failure to respond to selective serotonin reuptake inhibitors may result from abnormalities of neurotransmitter systems that excite serotonergic neurons, such as histamine. Methods: Using behavioral (tail suspension test) and neurochemical (in vivo microdialysis, Western-blot analysis) approaches, here we report that antidepressant responses to selective serotonin reuptake inhibitors (citalopram or paroxetine) are abolished in mice unable to synthesize histamine due to either targeted disruption of histidine decarboxylase gene (HDC-/-) or injection of alpha-fluoromethylhistidine, a suicide inhibitor of this enzyme. Results: In the tail suspension test, all classes of antidepressants tested reduced the immobility time of controls. Systemic reboxetine or imipramine reduced the immobility time of histamine-deprived mice as well, whereas selective serotonin reuptake inhibitors did not even though their serotonergic system is functional. In in vivo microdialysis experiments, citalopram significantly increased histamine extraneuronal levels in the cortex of freely moving mice, and methysergide, a serotonin 5-HT1/5-HT2 receptor antagonist, abolished this effect, thus suggesting the involvement of endogenous serotonin. CREB phosphorylation, which is implicated in the molecular mechanisms of antidepressant treatment, was abolished in histamine-deficient mice treated with citalopram. The CREB pathway is not impaired in HDC-/- mice, as administration of 8-bromoadenosine 3’, 5’-cyclic monophosphate increased CREB phosphorylation, and in the tail suspension test it significantly reduced the time spent immobile by mice of both genotypes. Conclusions: Our results demonstrate that selective serotonin reuptake inhibitors selectively require the integrity of the brain histamine system to exert their preclinical responses. PMID:25899065

Coriander Leaf Extract Exerts Antioxidant Activity and Protects Against UVB-Induced Photoaging of Skin by Regulation of Procollagen Type I and MMP-1 Expression

PubMed Central

Hwang, Eunson; Lee, Do-Gyeong; Park, Sin Hee; Oh, Myung Sook

2014-01-01

Abstract Ultraviolet (UV) radiation causes photodamage to the skin, which, in turn, leads to depletion of the dermal extracellular matrix and chronic alterations in skin structure. Skin wrinkles are associated with collagen synthesis and matrix metalloproteinase-1 (MMP-1) activity. Coriandrum sativum L. (coriander leaf, cilantro; CS) has been used as a herbal medicine for the treatment of diabetes, hyperlipidemia, liver disease, and cancer. In this study, we examined whether CS ethanol extract (CSE) has protective effects against UVB-induced skin photoaging in normal human dermal fibroblasts (NHDF) in vitro and in the skin of hairless mice in vivo. The main component of CSE, linolenic acid, was determined by gas chromatography-mass spectroscopy. We measured the cellular levels of procollagen type I and MMP-1 using ELISA in NHDF cells after UVB irradiation. NHDF cells that were treated with CSE after UVB irradiation exhibited higher procollagen type I production and lower levels of MMP-1 than untreated cells. We found that the activity of transcription factor activator protein-1 (AP-1) was also inhibited by CSE treatment. We measured the epidermal thickness, dermal collagen fiber density, and procollagen type I and MMP-1 levels in photo-aged mouse skin in vivo using histological staining and western blot analysis. Our results showed that CSE-treated mice had thinner epidermal layers and denser dermal collagen fibers than untreated mice. On a molecular level, it was further confirmed that CSE-treated mice had lower MMP-1 levels and higher procollagen type I levels than untreated mice. Our results support the potential of C. sativum L. to prevent skin photoaging. PMID:25019675

Coriander leaf extract exerts antioxidant activity and protects against UVB-induced photoaging of skin by regulation of procollagen type I and MMP-1 expression.

PubMed

Hwang, Eunson; Lee, Do-Gyeong; Park, Sin Hee; Oh, Myung Sook; Kim, Sun Yeou

2014-09-01

Ultraviolet (UV) radiation causes photodamage to the skin, which, in turn, leads to depletion of the dermal extracellular matrix and chronic alterations in skin structure. Skin wrinkles are associated with collagen synthesis and matrix metalloproteinase-1 (MMP-1) activity. Coriandrum sativum L. (coriander leaf, cilantro; CS) has been used as a herbal medicine for the treatment of diabetes, hyperlipidemia, liver disease, and cancer. In this study, we examined whether CS ethanol extract (CSE) has protective effects against UVB-induced skin photoaging in normal human dermal fibroblasts (NHDF) in vitro and in the skin of hairless mice in vivo. The main component of CSE, linolenic acid, was determined by gas chromatography-mass spectroscopy. We measured the cellular levels of procollagen type I and MMP-1 using ELISA in NHDF cells after UVB irradiation. NHDF cells that were treated with CSE after UVB irradiation exhibited higher procollagen type I production and lower levels of MMP-1 than untreated cells. We found that the activity of transcription factor activator protein-1 (AP-1) was also inhibited by CSE treatment. We measured the epidermal thickness, dermal collagen fiber density, and procollagen type I and MMP-1 levels in photo-aged mouse skin in vivo using histological staining and western blot analysis. Our results showed that CSE-treated mice had thinner epidermal layers and denser dermal collagen fibers than untreated mice. On a molecular level, it was further confirmed that CSE-treated mice had lower MMP-1 levels and higher procollagen type I levels than untreated mice. Our results support the potential of C. sativum L. to prevent skin photoaging.

Adaptations to excess choline in insulin resistant and Pcyt2 deficient skeletal muscle.

PubMed

Taylor, Adrian; Schenkel, Laila Cigana; Yokich, Maiya; Bakovic, Marica

2017-04-01

It was hypothesized that choline supplementation in insulin resistant (IR) CTP:phosphoethanolamine cytidylyltransferase deficient (Pcyt2 +/- ) mice would ameliorate muscle function by remodeling glucose and fatty acid (FA) metabolism. Pcyt2 +/- mice either received no treatment or were allowed access to 2 mg/mL choline in drinking water for 4 weeks. Skeletal muscle was harvested from choline treated and untreated mice. Lipid analysis and metabolic gene expression and signaling pathways were compared between untreated Pcyt2 +/- mice, treated Pcyt2 +/- mice, and Pcyt2 +/+ mice. The major positive effect of choline supplementation on IR muscle was the reduction of glucose utilization for FA and triglyceride (TAG) synthesis and increased muscle glucose storage as glycogen. Choline reduced the expression of genes for FA and TAG formation (Scd1, Fas, Srebp1c, Dgat1/2), upregulated the genes for FA oxidation (Cpt1, Pparα, Pgc1α), and had minor effects on phospholipid and lipolysis genes. Pcyt2 +/- muscle had reduced insulin signaling (IRS1), autophagy (LC3), and choline transport (CTL1) proteins that were restored by choline treatment. Additionally, choline activated AMPK and Akt while inhibiting mTORC1 phosphorylation. These data established that choline supplementation could restore muscle glucose metabolism by reducing lipogenesis and improving mitochondrial and intracellular signaling for protein and energy metabolism in insulin resistant Pcyt2 deficient mice.

LMW Heparin Prevents Increased Kidney Expression of Proinflammatory Mediators in (NZBxNZW)F1 Mice

PubMed Central

Kanapathippillai, Premasany; Rekvig, Ole Petter; Fenton, Kristin Andreassen

2013-01-01

We have previously demonstrated that continuous infusion of low molecular weight (LMW) heparin delays autoantibody production and development of lupus nephritis in (NZBxNZW)F1 (B/W) mice. In this study we investigated the effect of LMW heparin on renal cytokine and chemokine expression and on nucleosome-mediated activation of nucleosome-specific splenocytes. Total mRNA extracted from kidneys of heparin-treated or -untreated B/W mice was analysed by qPCR for the expression of several cytokines, chemokines, and Toll-like receptors. Splenocytes taken from B/W mice were stimulated with nucleosomes with or without the presence of heparin. Splenocyte cell proliferation as thymidine incorporation and the expression of costimulatory molecules and cell activation markers were measured. Heparin treatment of B/W mice reduced the in vivo expression of CCR2, IL1β, and TLR7 compared to untreated B/W mice. Nucleosome-induced cell proliferation of splenocytes was not influenced by heparin. The expression of CD80, CD86, CD69, CD25, CTLA-4, and TLR 2, 7, 8, and 9 was upregulated upon stimulation by nucleosomes, irrespective of whether heparin was added to the cell culture or not. In conclusion, treatment with heparin lowers the kidney expression of proinflammatory mediators in B/W mice but does not affect nucleosomal activation of splenocytes. PMID:24151519

FACTORS INFLUENCING HOST-VIRUS INTERACTIONS

PubMed Central

Boring, William D.; Angevine, D. Murray; Walker, Duard L.

1955-01-01

A study was made of the pathogenesis of infection due to the Conn.-5 strain of Coxsackie virus in 4 to 5 day old infant mice, untreated adult mice, and adult mice treated with cortisone. The quantitative distribution of virus and the evolution of lesions in different tissues were followed for the first 7 days of the infection. Virus dissemination was prompt and widespread via the blood in all groups. In 4 to 5 day old infant mice viral multiplication and cellular injury occurred in many organs and tissues, while in untreated adult mice these processes were largely limited to the pancreas, even though infecting virus appeared to be equally available to other tissues from the blood. Treatment of adult mice with a single injection of 2.5 mg. cortisone resulted in viral multiplication and tissue damage in several sites in addition to the pancreas, the most marked occurring in the liver and heart. In a consideration of possible mechanisms involved, it was thought unlikely that the differences in the course of the disease in the three groups could be attributed solely to differences in the specific immune response. It is suggested that developmental changes in cells and tissues, perhaps related to cellular metabolism and alterable by cortisone administration, are the major factors determining the location and extent of viral multiplication and tissue injury in this infection in mice. PMID:13271687

[Effects of gap junction blocking on the oxygen partial pressure in acupoints of the bladder meridian].

PubMed

Wang, Qi; Yu, Wei-Chang; Jiang, Hong-Zhi; Chen, Sheng-Li; Zhang, Ming-Min; Kong, E-Sheng; Huang, Guang-Ying

2010-12-01

To explore the relation between gap junction and meridian phenomenon. The oxygen partial pressure in acupoints [see text for formula] and in their corresponding non-acupoints of the Bladder Meridian was observed with the needle-type tissue oxygen tension sensor in the gap junction blocking goats by 1-Heptanol injection and the Connexin 43 (Cx43) gene knockout mice. (1) The oxygen partial pressure in acupoints of Bladder Meridian on goats was higher than that in non-acupoints after 1-Heptanol injection with significant differences between them (both P < 0.01). (2) The oxygen partial pressure in acupoints of Bladder Meridian on goats increased significantly after injecting 1-Heptanol as compare with that either injecting normal saline or injecting nothing with significant differences between them (all P < 0.01). (3) The oxygen partial pressure in acupoints of the Bladder Meridian was significantly higher than that in the non-acupoint controls in Cx43 wild type (WT) mice (all P < 0.01). In Cx43 heterozygote (HT) mice, the oxygen partial pressure between acupoints and non-acupoint controls showed no significant differences (all P > 0.05). (4) In acupoints, the oxygen partial pressure in Cx43 WT mice was significantly higher than that in Cx43 HT mice (all P < 0.05), while in the corresponding non-acupoints, this difference had no statistically significant (all P > 0.05). Gap junction maybe the essential factor in signal transduction of acupuncture.

Hallucinogen-like effects of 2-([2-(4-cyano-2,5-dimethoxyphenyl) ethylamino]methyl)phenol (25CN-NBOH), a novel N-benzylphenethylamine with 100-fold selectivity for 5-HT2A receptors, in mice

PubMed Central

Gray, Bradley W.; Bailey, Jessica M.; Smith, Douglas; Hansen, Martin; Kristensen, Jesper L.

2014-01-01

Rationale 2-([2-(4-cyano-2,5-dimethoxyphenyl)ethylamino]methyl)phenol (25CN-NBOH) is structurally similar to N-benzyl substituted phenethylamine hallucinogens currently emerging as drugs of abuse. 25CN-NBOH exhibits dramatic selectivity for 5-HT2A receptors in vitro, but has not been behaviorally characterized. Objective 25CN-NBOH was compared to the traditional phenethylamine hallucinogen R(−)-2,5-dimethoxy-4-iodoamphetamine (DOI) using mouse models of drug-elicited head twitch behavior and drug discrimination. Methods Drug-elicited head twitches were quantified for 10 min following administration of various doses of either DOI or 25CN-NBOH, with and without pretreatments of 0.01 mg/kg 5-HT2A antagonist M100907 or 3.0 mg/kg 5-HT2C antagonist RS102221. The capacity of 25CN-NBOH to attenuate DOI-elicited head twitch was also investigated. Mice were trained to discriminate DOI or M100907 from saline, and 25CN-NBOH was tested for generalization. Results 25CN-NBOH induced a head twitch response in the mouse that was lower in magnitude than that of DOI, blocked by M100907, but not altered by RS102221. DOI-elicited head twitch was dose-dependently attenuated by 25CN-NBOH pretreatment. 25CN-NBOH produced an intermediate degree of generalization (55%) for the DOI training dose, and these interoceptive effects were attenuated by M100907. Finally, 25CN-NBOH did not generalize to M100907 at any dose, but ketanserin fully substituted in these animals. Conclusions 25CN-NBOH was behaviorally active, but less effective than DOI in two mouse models of hallucinogenic effects. The effectiveness with which M100907 antagonized the behavioral actions of 25CN-NBOH strongly suggests that the 5-HT2A receptor is an important site of agonist action for this compound in vivo. PMID:25224567

Antidepressant-like effect of gallic acid in mice: Dual involvement of serotonergic and catecholaminergic systems.

PubMed

Can, Özgür Devrim; Turan, Nazlı; Demir Özkay, Ümide; Öztürk, Yusuf

2017-12-01

This study was planned to examine the antidepressant potency of gallic acid (30 and 60mg/kg), a phenolic acid widely distributed in nature, together with its possible underlying monoaminergic mechanisms. Antidepressant-like activity was assessed using the tail suspension (TST) and the modified forced swimming tests (MFST). Locomotor activity was evaluated in an activity cage. Administration of gallic acid at 60mg/kg reduced the immobility duration of mice in both the TST and MFST without any changes in the locomotor activity. The anti-immobility effect observed in the TST was abolished with pre-treatment of p-chlorophenylalanine methyl ester (an inhibitor of serotonin synthesis; 100mg/kg i.p. administered for 4-consecutive days), ketanserin (a 5-HT2A/2C antagonist; 1mg/kg i.p.), ondansetron (a 5-HT3 antagonist; 0.3mg/kg i.p.), α-methyl-para-tyrosine methyl ester (an inhibitor of catecholamine synthesis; 100mg/kg i.p.), phentolamine (non-selective alpha-adrenoceptor antagonist; 5mg/kg i.p.), SCH 23390 (a dopamine D1 antagonist; 0.05mg/kg s.c.), and sulpiride (a dopamine D2/D3 antagonist; 50mg/kg i.p.). However, NAN 190 (a 5-HT1A antagonist; 0.5mg/kg i.p.) and propranolol (a non-selective β-adrenoceptor antagonist; 5mg/kg i.p.) pre-treatments were ineffective at reversing the antidepressant-like effects of gallic acid. The results of the present study indicate that gallic acid seems to have a dual mechanism of action by increasing not only serotonin but also catecholamine levels in synaptic clefts of the central nervous system. Further alpha adrenergic, 5-HT2A/2C and 5-HT3 serotonergic, and D1, D2, and D3 dopaminergic receptors also seem to be involved in this antidepressant-like activity. Copyright © 2017 Elsevier Inc. All rights reserved.

The effect of the sigma-1 receptor selective compound LS-1-137 on the DOI-induced head twitch response in mice.

PubMed

Malik, Maninder; Rangel-Barajas, Claudia; Mach, Robert H; Luedtke, Robert R

2016-09-01

Several receptor mediated pathways have been shown to modulate the murine head twitch response (HTR). However, the role of sigma receptors in the murine (±)-2,5-dimethoxy-4-iodoamphetamine (DOI)-induced HTR has not been previously investigated. We examined the ability of LS-1-137, a novel sigma-1 vs. sigma-2 receptor selective phenylacetamide, to modulate the DOI-induced HTR in DBA/2J mice. We also assessed the in vivo efficacy of reference sigma-1 receptor antagonists and agonists PRE-084 and PPCC. The effect of the sigma-2 receptor selective antagonist RHM-1-86 was also examined. Rotarod analysis was performed to monitor motor coordination after LS-1-137 administration. Radioligand binding techniques were used to determine the affinity of LS-1-137 at 5-HT2A and 5-HT2C receptors. LS-1-137 and the sigma-1 receptor antagonists haloperidol and BD 1047 were able to attenuate a DOI-induced HTR, indicating that LS-1-137 was acting in vivo as a sigma-1 receptor antagonist. LS-1-137 did not compromise rotarod performance within a dose range capable of attenuating the effects of DOI. Radioligand binding studies indicate that LS-1-137 exhibits low affinity binding at both 5-HT2A and 5-HT2C receptors. Based upon the results from these and our previous studies, LS-1-137 is a neuroprotective agent that attenuates the murine DOI-induced HTR independent of activity at 5-HT2 receptor subtypes, D2-like dopamine receptors, sigma-2 receptors and NMDA receptors. LS-1-137 appears to act as a sigma-1 receptor antagonist to inhibit the DOI-induced HTR. Therefore, the DOI-induced HTR can be used to assess the in vivo efficacy of sigma-1 receptor selective compounds. Copyright © 2016. Published by Elsevier Inc.

THE EFFICACY OF THREE MEDICINAL PLANTS; GARLIC, GINGER AND MIRAZID AND A CHEMICAL DRUG METRONIDAZOLE AGAINST CRYPTOSPORIDIUM PARVUM: II-HISTOLOGICAL CHANGES.

PubMed

Abouel-Nour, Mohamed F; El-Shewehy, Dina Magdy M; Hamada, Shadia F; Morsy, Tosson A

2016-04-01

Cryptosporidiosis parvum is a zoonotic protozoan parasite infects intestinal epithelial cells of man and animals causing a major health problem. This study was oriented to evaluate the protective and curative capacity of garlic, ginger and mirazid in comparison with metronidazole drug (commercially known) against Cryptosporidium in experimental mice. Male Swiss Albino mice experimentally infected with C. parvum were treated with medicinal plants extracts (Ginger, Mirazid, and Garlic) as compared to chemical drug Metronidazole. Importantly, C. parvum-infected mice treated with ginger, Mirazid, garlic and metronidazole showed a complete elimination in shedding oocysts by 9th day PI. The reduction and elimination of shedding oocysts in response to the treatments might be attributable to a direct effect on parasite growth in intestines, sexual phases production and/or the formation of oocysts. The results were evaluated histopathological examination of ideum section of control mice (uninfected, untreated) displayed normal architecture of the villi. Examiination of infected mice ileum section (infected, untreated) displayed histopathological alterations from uninfected groups. Examination of ileum section prepared from mice treated with garlic, ginger, mirazid, and metronidazole displayed histopathological alterations from that of the control groups, and showed marked histologic correction in the pattern with the four regimes used in comparison to control mice. Garlic successfully eradicated oocysts of infected mice from stool and intestine. Supplementation of ginger to infected mice markedly corrected elevation in the inflammatory risk factors and implied its potential antioxidant, anti-inflammatory and immunomodulatory capabilities. Infected mice treated with ginger, mirazid, garlic and metronidazole showed significant symptomatic improvements during treatment.

Characterization of the head-twitch response induced by hallucinogens in mice: detection of the behavior based on the dynamics of head movement.

PubMed

Halberstadt, Adam L; Geyer, Mark A

2013-06-01

The head-twitch response (HTR) is a rapid side-to-side rotational head movement that occurs in rats and mice after administration of serotonergic hallucinogens and other 5-HT2A agonists. The HTR is widely used as a behavioral assay for 5-HT2A activation and to probe for interactions between the 5-HT2A receptor and other transmitter systems. High-speed video recordings were used to analyze the head movement that occurs during head twitches in C57BL/6J mice. Experiments were also conducted in C57BL/6J mice to determine whether a head-mounted magnet and a magnetometer coil could be used to detect the HTR induced by serotonergic hallucinations based on the dynamics of the response. Head movement during the HTR was highly rhythmic and occurred within a specific frequency range (mean head movement frequency of 90.3 Hz). Head twitches produced wave-like oscillations of magnetometer coil voltage that matched the frequency of head movement during the response. The magnetometer coil detected the HTR induced by the serotonergic hallucinogens 2,5-dimethoxy-4-iodoamphetamine (DOI; 0.25, 0.5, and 1.0 mg/kg, i.p.) and lysergic acid diethylamide (LSD; 0.05, 0.1, 0.2, and 0.4 mg/kg, i.p.) with extremely high sensitivity and specificity. Magnetometer coil recordings demonstrated that the non-hallucinogenic compounds (+)-amphetamine (2.5 and 5.0 mg/kg, i.p.) and lisuride (0.8, 1.6, and 3.2 mg/kg, i.p.) did not induce the HTR. These studies confirm that a magnetometer coil can be used to detect the HTR induced by hallucinogens. The use of magnetometer-based HTR detection provides a high-throughput, semi-automated assay for this behavior, and offers several advantages over traditional assessment methods.

Characterization of the head-twitch response induced by hallucinogens in mice: detection of the behavior based on the dynamics of head movement

PubMed Central

Halberstadt, Adam L.; Geyer, Mark A.

2013-01-01

Rationale The head-twitch response (HTR) is a rapid side-to-side rotational head movement that occurs in rats and mice after administration of serotonergic hallucinogens and other 5-HT2A agonists. The HTR is widely used as a behavioral assay for 5-HT2A activation and to probe for interactions between the 5-HT2A receptor and other transmitter systems. Objective High-speed video recordings were used to analyze the head movement that occurs during head twitches in C57BL/6J mice. Experiments were also conducted in C57BL/6J mice to determine whether a head-mounted magnet and a magnetometer coil could be used to detect the HTR induced by serotonergic hallucinations based on the dynamics of the response. Results Head movement during the HTR was highly rhythmic and occurred within a specific frequency range (mean reciprocation frequency of 90.3 Hz). Head twitches produced wave-like oscillations of magnetometer coil voltage that matched the frequency of head movement during the response. The magnetometer coil detected the HTR induced by the serotonergic hallucinogens 2,5-dimethoxy-4-iodoamphetamine (DOI; 0.25, 0.5, and 1.0 mg/kg, IP) and lysergic acid diethylamide (LSD; 0.05, 0.1, 0.2, and 0.4 mg/kg, IP) with extremely high sensitivity and specificity. Magnetometer coil recordings demonstrated that the non-hallucinogenic compounds (+)-amphetamine (2.5 and 5.0 mg/kg, IP) and lisuride (0.8, 1.6, and 3.2 mg/kg, IP) did not induce the HTR. Conclusions These studies confirm that a magnetometer coil can be used to detect the HTR induced by hallucinogens. The use of magnetometer-based HTR detection provides a high-throughput, semi-automated assay for this behavior, and offers several advantages over traditional assessment methods. PMID:23407781

Hematopoietic stem cells found in lineage-positive subsets in the bone marrow of 5-fluorouracil-treated mice.

PubMed

Nishi, N; Osawa, M; Ishikawa, R; Nishikawa, M; Tsumura, H; Inoue, H; Sudo, T

1995-09-01

It is known that treatment of mice with 5-fluorouracil (5-FU, 150 mg/kg) confers radioprotection. To investigate this effect, we performed bone marrow transplantation (BMT) using C57BL/6-Ly5 congenic mice treated with 5-FU five days prior to experiments. The mononuclear cells (MNC) in 5-FU-treated bone marrow (BM) were 10 times more radioprotective than those in untreated BM. Moreover, the number of BM MNC expressing c-kit on their surface from 5-FU-treated mice was markedly decreased relative to those from untreated controls. These results showed that the surface characteristics of cells that contributed to this radio-protective effect differ from those of stem cells as reported recently. BM MNC of mice treated with 5-FU were separated on the basis of expression of the lineage-specific antigens (Lin), c-kit, and Ly6A/E. When injected into lethally irradiated mice, 1,000 Lin+ and Lin-c-kit+Ly6A/E+ cells showed radioprotective effects such that 100% and 60% survived, respectively. Flow cytometric analysis 165 days after BMT showed that 88.8% and 65.1% of peripheral blood (PB) in mice transplanted with Lin+ and Lin-c-kit+Ly6A/E+ was derived from donor mice, respectively. After six months, donor-derived Lin-c-kit+Ly6A/E+ cells which showed radioprotective effects on a secondary irradiated host were detected from mice transplanted with Lin+ cells from 5-FU-treated mice. Taken together, these findings demonstrated that stem cells expressing Lin+ present in the BM of mice treated with 5-FU other than Lin-c-kit+Ly6A/E+ cells and these Lin+ cells play an important role in the recovery of myeloablative mice.

Enhanced prefrontal serotonin 2A receptor signaling in the subchronic phencyclidine mouse model of schizophrenia.

PubMed

Santini, Martin A; Ratner, Cecilia; Aznar, Susana; Klein, Anders B; Knudsen, Gitte M; Mikkelsen, Jens D

2013-05-01

Prefrontal serotonin 2A receptors (5-HT2A Rs) have been linked to the pathogenesis and treatment of schizophrenia. Many antipsychotics fully occupy 5-HT2A R at clinical relevant doses, and activation of 5-HT2A receptors by lysergic acid diethylamide (LSD) and LSD-like drugs induces a schizophrenia-like psychosis in humans. Subchronic phencyclidine (PCP) administration is a well-established model for schizophrenia-like symptoms in rodents. The aim of the present study was to investigate whether subchronic PCP administration changes expression, binding, or functionality of cortical 5-HT2A Rs. As a measure of 5-HT2A R functionality, we used the 5-HT2A R agonist 2,5-dimethoxy-4-iodoamphetamine (DOI)-induced head-twitch response (HTR) and mRNA expression of the immediate-early genes (IEGs) activity-related cytoskeletal associated-protein (Arc), c-fos, and early growth response protein 2 (egr-2) in the frontal cortex. Mice were treated with PCP (10 mg/kg) or saline for 10 days, followed by a 5-day washout period. The PCP pretreatment increased the overall induction of HTR and frontal cortex IEG mRNA expression following a single challenge with DOI. These functional changes were not associated with changes in 5-HT2A R binding. Also, binding of the 5-HT1A R and the 5-HT transporter was unaffected. Finally, basal mRNA level of Arc was increased in the prefrontal cortex after subchronic PCP administration as revealed with in situ hybridization. Together these findings indicate that PCP administration produces changes in the brain that result in an increase in the absolute effect of DOI. Therefore, neurotransmission involving the 5-HT2A R could contribute to the behavioral deficits observed after PCP treatment. © 2013 Wiley Periodicals, Inc. Copyright © 2013 Wiley Periodicals, Inc.

Paroxetine and Low-dose Risperidone Induce Serotonin 5-HT1A and Dopamine D2 Receptor Heteromerization in the Mouse Prefrontal Cortex.

PubMed

Kolasa, Magdalena; Solich, Joanna; Faron-Górecka, Agata; Żurawek, Dariusz; Pabian, Paulina; Łukasiewicz, Sylwia; Kuśmider, Maciej; Szafran-Pilch, Kinga; Szlachta, Marta; Dziedzicka-Wasylewska, Marta

2018-05-01

Recently, it has been shown that serotonin 5-HT 1A receptor interacts with dopamine D2 receptor in vitro. However, the existence of 5-HT 1A -D2 heteromers in native tissue remains unexplored. In the present study, we investigated 5-HT 1A -D2 receptor heteromerization in mice treated acutely or chronically with paroxetine (10 mg/kg) or risperidone (0.05 mg/kg). Receptor heteromerization was visualized and quantified in the mouse brain by in situ proximity ligation assay (PLA). Additionally, we aimed to determine the cellular localization of 5-HT 1A -D2 receptor heteromers in mouse adult primary neuronal cells by immunofluorescent staining with markers for astrocytes (GFAP) and neurons (NeuN and MAP2). The results from the current study demonstrated that 5-HT 1A and D2 receptor co-localization and heteromerization occurred in the mouse prefrontal cortex. Counterstaining after PLA confirmed neuronal (pyramidal and GABAergic) as well as astrocytal localization of 5-HT 1A -D2 receptor heteromers. Chronic administration of paroxetine or risperidone increased the level of 5-HT 1A -D2 receptor heteromers in the prefrontal cortex. These changes were not accompanied by any changes in the expression of mRNAs (measured by in situ hybridization) or densities of 5-HT 1A and D2 receptors (quantified by receptor autoradiography with [3H]8-OH-DPAT and [3H]domperidone, respectively), what all indicated that paroxetine and risperidone facilitated 5-HT 1A -D2 heteromer formation independently of the receptor expression. In vitro homogenous time-resolved FRET (HTRF) study confirmed the ability of tested drugs to influence the human 5-HT 1A -D2 heteromer formation. The obtained data indicate that the increase in 5-HT 1A -D2 receptor heteromerization is a common molecular characteristic of paroxetine and low-dose risperidone treatment. Copyright © 2018 IBRO. Published by Elsevier Ltd. All rights reserved.