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Sample records for 5-ht1a receptor knockout

  1. Altered photic and non-photic phase shifts in 5-HT(1A) receptor knockout mice.

    PubMed

    Smith, V M; Sterniczuk, R; Phillips, C I; Antle, M C

    2008-12-01

    The mammalian circadian clock located in the suprachiasmatic nucleus (SCN) is thought to be modulated by 5-HT. 5-HT is though to inhibit photic phase shifts by inhibiting the release of glutamate from retinal terminals, as well as by decreasing the responsiveness of retinorecipient cells in the SCN. Furthermore, there is also evidence that 5-HT may underlie, in part, non-photic phase shifts of the circadian system. Understanding the mechanism by which 5-HT accomplishes these goals is complicated by the wide variety of 5-HT receptors found in the SCN, the heterogeneous organization of both the circadian clock and the location of 5-HT receptors, and by a lack of sufficiently selective pharmacological agents for the 5-HT receptors of interest. Genetically modified animals engineered to lack a specific 5-HT receptor present an alternative avenue of investigation to understand how 5-HT regulates the circadian system. Here we examine behavioral and molecular responses to both photic and non-photic stimuli in mice lacking the 5-HT(1A) receptor. When compared with wild-type controls, these mice exhibit larger phase advances to a short late-night light pulse and larger delays to long 12 h light pulses that span the whole subjective night. Fos and mPer1 expression in the retinorecipient SCN is significantly attenuated following late-night light pulses in the 5-HT(1A) knockout animals. Finally, non-photic phase shifts to (+/-)-8-hydroxy-2-(dipropylamino)tetralin hydrobromide (8-OH-DPAT) are lost in the knockout animals, while attenuation of the phase shift to the long light pulse due to rebound activity following a wheel lock is unaffected. These findings suggest that the 5-HT(1A) receptor plays an inhibitory role in behavioral phase shifts, a facilitatory role in light-induced gene expression, a necessary role in phase shifts to 8-OH-DPAT, and is not necessary for activity-induced phase advances that oppose photic phase shifts to long light pulses.

  2. Blockade of 5-HT1A receptors by (+/-)-pindolol potentiates cortical 5-HT outflow, but not antidepressant-like activity of paroxetine: microdialysis and behavioral approaches in 5-HT1A receptor knockout mice.

    PubMed

    Guilloux, Jean-Philippe; David, Denis J P; Guiard, Bruno P; Chenu, Franck; Repérant, Christelle; Toth, Miklos; Bourin, Michel; Gardier, Alain M

    2006-10-01

    Selective serotonin reuptake inhibitors like paroxetine (Prx) often requires 4-6 weeks to achieve clinical benefits in depressed patients. Pindolol shortens this delay and it has been suggested that this effect is mediated by somatodendritic 5-hydroxytryptamine (5-HT) 1A autoreceptors. However clinical data on the beneficial effects of pindolol are conflicting. To study the effects of (+/-)-pindolol-paroxetine administration, we used genetical and pharmacological approaches in 5-HT1A knockout mice (5-HT1A-/-). Two assays, in vivo intracerebral microdialysis in awake mice and the forced swimming test (FST), were used to assess the antidepressant-like effects of this drug combination. Basal levels of extracellular serotonin, 5-HT ([5-HT]ext) in the frontal cortex (FCX) and the dorsal raphe nucleus (DRN) did not differ between the two strains of mice, suggesting a lack of tonic control of 5-HT1A autoreceptors on nerve terminal 5-HT release. Prx (1 and 4 mg/kg) dose-dependently increased cortical [5-HT]ext in both genotypes, but the effects were greater in mutants. The selective 5-HT1A receptor antagonist, WAY-100635 (0.5 mg/kg), or (+/-)-pindolol (5 and 10 mg/kg) potentiated the effects of Prx (4 mg/kg) on cortical [5-HT]ext in 5-HT1A+/+, but not in 5-HT1A-/- mice. Similar responses were obtained following local intra-raphe perfusion by reverse microdialysis of either WAY-100635 or (+/-)-pindolol (100 microM each). In the FST, Prx administration dose-dependently decreased the immobility time in both strains of mice, but the response was much greater in 5HT1A-/- mice. In contrast, (+/-)-pindolol blocked Prx-induced decreases in the immobility time while WAY-100635 had no effect in both genotypes. These findings using 5-HT1A-/- mice confirm that (+/-)-pindolol behaves as an antagonist of 5-HT1A autoreceptor in mice, but its blockade of paroxetine-induced antidepressant-like effects in the FST may be due to its binding to other neurotransmitter receptors.

  3. Interaction between 5-HT(1A) and 5-HT(1B) receptors: effects of 8-OH-DPAT-induced hypothermia in 5-HT(1B) receptor knockout mice.

    PubMed

    Gardier, A M; Gruwez, B; Trillat, A C; Jacquot, C; Hen, R; Bourin, M

    2001-06-15

    To test for adaptive compensatory changes that may have occurred in the functional activity of somatodendritic 5-HT(1A) receptors during the development of constitutive "knockout" mice lacking the 5-HT(1B) receptor subtype (5-HT(1B) -/- KO), we assayed for decrease in body temperature induced by an acute subcutaneous injection of the 5-HT(1A) receptor agonist, 8-hydroxy 2(di-n-propyl(amino)tetralin (8-OH-DPAT), either alone or in the presence of a selective 5-HT(1A) receptor antagonist, N-[4-(2-methoxyphenyl)-1-piperazinyl]-N-(2-pyridinyl) cyclo-hexanecarboxamide (WAY 100635). We compared dose-response curves, time course study, calculated ED(50) values (potency), maximal response to 8-OH-DPAT (efficacy) as well as measurements of the dose-dependent blockade of this response by WAY 100635 between wild-type controls and mutant mice. We found a higher efficacy of 8-OH-DPAT-induced hypothermia in 5-HT(1B) -/- KO compared to wild-type mice suggesting that an adaptive thermoregulatory process involving the functional activity of somatodendritic 5-HT(1A) receptors is altered in mutant mice lacking 5-HT(1B) receptors.

  4. 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.

  5. Medial hypothalamic 5-hydroxytryptamine (5-HT)1A receptors regulate neuroendocrine responses to stress and exploratory locomotor activity: application of recombinant adenovirus containing 5-HT1A sequences.

    PubMed

    Li, Qian; Holmes, Andrew; Ma, Li; Van de Kar, Louis D; Garcia, Francisca; Murphy, Dennis L

    2004-12-01

    Our previous studies found that serotonin transporter (SERT) knock-out mice showed increased sensitivity to minor stress and increased anxiety-like behavior but reduced locomotor activity. These mice also showed decreased density of 5-hydroxytryptamine (5-HT1A) receptors in the hypothalamus, amygdala, and dorsal raphe. To evaluate the contribution of hypothalamic 5-HT1A receptors to these phenotypes of SERT knock-out mice, two studies were conducted. Recombinant adenoviruses containing 5-HT1A sense and antisense sequences (Ad-1AP-sense and Ad-1AP-antisense) were used to manipulate 5-HT1A receptors in the hypothalamus. The expression of the 5-HT1A genes is controlled by the 5-HT1A promoter, so that they are only expressed in 5-HT1A receptor-containing cells. (1) Injection of Ad-1AP-sense into the hypothalamus of SERT knock-out mice restored 5-HT1A receptors in the medial hypothalamus; this effect was accompanied by elimination of the exaggerated adrenocorticotropin responses to a saline injection (minor stress) and reduced locomotor activity but not by a change in increased exploratory anxiety-like behavior. (2) To further confirm the observation in SERT-/- mice, Ad-1AP-antisense was injected into the hypothalamus of normal mice. The density and the function of 5-HT1A receptors in the medial hypothalamus were significantly reduced in Ad-1AP-antisense-treated mice. Compared with the control group (injected with Ad-track), Ad-1A-antisense-treated mice showed a significant reduction in locomotor activity, but again no changes in exploratory anxiety-like behaviors, tested by elevated plus-maze and open-field tests. Thus, the present results demonstrate that medial hypothalamic 5-HT1A receptors regulate stress responses and locomotor activity but may not regulate exploratory anxiety-like behaviors. PMID:15574737

  6. 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

  7. Yokukansan Increases 5-HT1A Receptors in the Prefrontal Cortex and Enhances 5-HT1A Receptor Agonist-Induced Behavioral Responses in Socially Isolated Mice

    PubMed Central

    Ueki, Toshiyuki; Mizoguchi, Kazushige; Yamaguchi, Takuji; Nishi, Akinori; Ikarashi, Yasushi; Hattori, Tomohisa; Kase, Yoshio

    2015-01-01

    The traditional Japanese medicine yokukansan has an anxiolytic effect, which occurs after repeated administration. In this study, to investigate the underlying mechanisms, we examined the effects of repeated yokukansan administration on serotonin 1A (5-HT1A) receptor density and affinity and its expression at both mRNA and protein levels in the prefrontal cortex (PFC) of socially isolated mice. Moreover, we examined the effects of yokukansan on a 5-HT1A receptor-mediated behavioral response. Male mice were subjected to social isolation stress for 6 weeks and simultaneously treated with yokukansan. Thereafter, the density and affinity of 5-HT1A receptors were analyzed by a receptor-binding assay. Levels of 5-HT1A receptor protein and mRNA were also measured. Furthermore, (±)-8-hydroxy-2-(dipropylamino)tetralin hydrobromide (8-OH-DPAT; a 5-HT1A receptor agonist) was injected intraperitoneally, and rearing behavior was examined. Social isolation stress alone did not affect 5-HT1A receptor density or affinity. However, yokukansan significantly increased receptor density and decreased affinity concomitant with unchanged protein and mRNA levels. Yokukansan also enhanced the 8-OH-DPAT-induced decrease in rearing behavior. These results suggest that yokukansan increases 5-HT1A receptors in the PFC of socially isolated mice and enhances their function, which might underlie its anxiolytic effects. PMID:26681968

  8. Stress-induced alterations in 5-HT1A receptor transcriptional modulators NUDR and Freud-1.

    PubMed

    Szewczyk, Bernadeta; Kotarska, Katarzyna; Daigle, Mireille; Misztak, Paulina; Sowa-Kucma, Magdalena; Rafalo, Anna; Curzytek, Katarzyna; Kubera, Marta; Basta-Kaim, Agnieszka; Nowak, Gabriel; Albert, Paul R

    2014-11-01

    The effect of stress on the mRNA and protein level of the 5-HT1A receptor and two of its key transcriptional modulators, NUDR and Freud-1, was examined in the prefrontal cortex (PFC) and hippocampus (Hp) using rodent models: olfactory bulbectomy (OB) and prenatal stress (PS) in male and female rats; chronic mild stress in male rats (CMS) and pregnancy stress. In PFC, CMS induced the most widespread changes, with significant reduction in both mRNA and protein levels of NUDR, 5-HT1A receptor and in Freud-1 mRNA; while in Hp 5-HT1A receptor and Freud-1 protein levels were also decreased. In male, but not female OB rats PFC Freud-1 and 5-HT1A receptor protein levels were reduced, while in Hp 5-HT1A receptor, Freud-1 and NUDR mRNA's but not protein were reduced. In PS rats PFC 5-HT1A receptor protein was reduced more in females than males; while in Hp Freud-1 protein was increased in females. In pregnancy stress, PFC NUDR, Freud-1 and 5-HT1A protein receptor levels were reduced, and in HP 5-HT1A receptor protein levels were also reduced; in HP only NUDR and Freud-1 mRNA levels were reduced. Overall, CMS and stress during pregnancy produced the most salient changes in 5-HT1A receptor and transcription factor expression, suggesting a primary role for altered transcription factor expression in chronic regulation of 5-HT1A receptor expression. By contrast, OB (in males) and PS (in females) produced gender-specific reductions in PFC 5-HT1A receptor protein levels, suggesting a role for post-transcriptional regulation. These and previous data suggest that chronic stress might be a key regulator of NUDR/Freud-1 gene expression.

  9. Increased serotonin-1A (5-HT1A) autoreceptor expression and reduced raphe serotonin levels in deformed epidermal autoregulatory factor-1 (Deaf-1) gene knock-out mice.

    PubMed

    Czesak, Margaret; Le François, Brice; Millar, Anne M; Deria, Mariam; Daigle, Mireille; Visvader, Jane E; Anisman, Hymie; Albert, Paul R

    2012-02-24

    Altered regulation of the serotonin-1A (5-HT1A) receptor gene is implicated in major depression and mood disorders. The functional human 5-HT1A C(-1019)G promoter polymorphism (rs6295), which prevents the binding of Deaf-1/NUDR leading to dysregulation of the receptor, has been associated with major depression. In cell models Deaf-1 displays dual activity, repressing 5-HT1A autoreceptor expression in serotonergic raphe cells while enhancing postsynaptic 5-HT1A heteroreceptor expression in nonserotonergic neurons. A functional Deaf-1 binding site on the mouse 5-HT1A promoter was recognized by Deaf-1 in vitro and in vivo and mediated dual activity of Deaf-1 on 5-HT1A gene transcription. To address regulation by Deaf-1 in vivo, Deaf-1 knock-out mice bred to a C57BL/6 background were compared with wild-type siblings for changes in 5-HT1A RNA and protein by quantitative RT-PCR, in situ hybridization, and immunofluorescence. In the dorsal raphe, Deaf-1 knock-out mice displayed increased 5-HT1A mRNA, protein, and 5-HT1A-positive cell counts but reduced 5-HT levels, whereas other serotonergic markers, such as tryptophan hydroxylase (TPH)- or 5-HT-positive cells and TPH2 RNA levels, were unchanged. By contrast, 5-HT1A mRNA and 5-HT1A-positive cells were reduced in the frontal cortex of Deaf-1-null mice, with no significant change in hippocampal 5-HT1A RNA, protein, or cell counts. The region-specific alterations of brain 5-HT1A gene expression and reduced raphe 5-HT content in Deaf-1(-/-) mice indicate the importance of Deaf-1 in regulation of 5-HT1A gene expression and provide insight into the role of the 5-HT1A G(-1019) allele in reducing serotonergic neurotransmission by derepression of 5-HT1A autoreceptors.

  10. Application of Quantitative Structure–Activity Relationship Models of 5-HT1A Receptor Binding to Virtual Screening Identifies Novel and Potent 5-HT1A Ligands

    PubMed Central

    2015-01-01

    The 5-hydroxytryptamine 1A (5-HT1A) serotonin receptor has been an attractive target for treating mood and anxiety disorders such as schizophrenia. We have developed binary classification quantitative structure–activity relationship (QSAR) models of 5-HT1A receptor binding activity using data retrieved from the PDSP Ki database. The prediction accuracy of these models was estimated by external 5-fold cross-validation as well as using an additional validation set comprising 66 structurally distinct compounds from the World of Molecular Bioactivity database. These validated models were then used to mine three major types of chemical screening libraries, i.e., drug-like libraries, GPCR targeted libraries, and diversity libraries, to identify novel computational hits. The five best hits from each class of libraries were chosen for further experimental testing in radioligand binding assays, and nine of the 15 hits were confirmed to be active experimentally with binding affinity better than 10 μM. The most active compound, Lysergol, from the diversity library showed very high binding affinity (Ki) of 2.3 nM against 5-HT1A receptor. The novel 5-HT1A actives identified with the QSAR-based virtual screening approach could be potentially developed as novel anxiolytics or potential antischizophrenic drugs. PMID:24410373

  11. Application of quantitative structure-activity relationship models of 5-HT1A receptor binding to virtual screening identifies novel and potent 5-HT1A ligands.

    PubMed

    Luo, Man; Wang, Xiang Simon; Roth, Bryan L; Golbraikh, Alexander; Tropsha, Alexander

    2014-02-24

    The 5-hydroxytryptamine 1A (5-HT1A) serotonin receptor has been an attractive target for treating mood and anxiety disorders such as schizophrenia. We have developed binary classification quantitative structure-activity relationship (QSAR) models of 5-HT1A receptor binding activity using data retrieved from the PDSP Ki database. The prediction accuracy of these models was estimated by external 5-fold cross-validation as well as using an additional validation set comprising 66 structurally distinct compounds from the World of Molecular Bioactivity database. These validated models were then used to mine three major types of chemical screening libraries, i.e., drug-like libraries, GPCR targeted libraries, and diversity libraries, to identify novel computational hits. The five best hits from each class of libraries were chosen for further experimental testing in radioligand binding assays, and nine of the 15 hits were confirmed to be active experimentally with binding affinity better than 10 μM. The most active compound, Lysergol, from the diversity library showed very high binding affinity (Ki) of 2.3 nM against 5-HT1A receptor. The novel 5-HT1A actives identified with the QSAR-based virtual screening approach could be potentially developed as novel anxiolytics or potential antischizophrenic drugs.

  12. Pharmacology of the hypothermic response to 5-HT1A receptor activation in humans.

    PubMed

    Lesch, K P; Poten, B; Söhnle, K; Schulte, H M

    1990-01-01

    The selective 5-HT1A receptor ligand ipsapirone (IPS) caused dose-related hypothermia in humans. The response was attenuated by the nonselective 5-HT1/2 receptor antagonist metergoline and was completely antagonized by the nonselective beta-adrenoceptor antagonist pindolol, which interacts stereoselectively with the 5-HT1A receptor. The selective beta 1-adrenergic antagonist betaxolol had no effect. The findings indicate that IPS-induced hypothermia specifically involves activation of (presynaptic) 5-HT1A receptors. Therefore, the hypothermic response to IPS may provide a convenient in vivo paradigma to assess the function of the presynaptic 5-HT receptor in affective disorders and its involvement in the effects of psychotropic drugs. PMID:1980461

  13. Pharmacology of the hypothermic response to 5-HT1A receptor activation in humans.

    PubMed

    Lesch, K P; Poten, B; Söhnle, K; Schulte, H M

    1990-01-01

    The selective 5-HT1A receptor ligand ipsapirone (IPS) caused dose-related hypothermia in humans. The response was attenuated by the nonselective 5-HT1/2 receptor antagonist metergoline and was completely antagonized by the nonselective beta-adrenoceptor antagonist pindolol, which interacts stereoselectively with the 5-HT1A receptor. The selective beta 1-adrenergic antagonist betaxolol had no effect. The findings indicate that IPS-induced hypothermia specifically involves activation of (presynaptic) 5-HT1A receptors. Therefore, the hypothermic response to IPS may provide a convenient in vivo paradigma to assess the function of the presynaptic 5-HT receptor in affective disorders and its involvement in the effects of psychotropic drugs.

  14. Development of 5-HT1A receptor radioligands to determine receptor density and changes in endogenous 5-HT.

    PubMed

    Jagoda, Elaine M; Lang, Lixin; Tokugawa, Joji; Simmons, Ashlie; Ma, Ying; Contoreggi, Carlo; Kiesewetter, Dale; Eckelman, William C

    2006-05-01

    [(18)F]FCWAY and [(18)F]FPWAY, analogues of the high affinity 5-HT(1A) receptor (5-HT(1A)R) antagonist WAY100635, were evaluated in rodents as potential radiopharmaceuticals for determining 5-HT(1A)R density and changes in receptor occupancy due to changes in endogenous serotonin (5-HT) levels. The in vivo hippocampus specific binding ratio [(hippocampus(uptake)/cerebellum(uptake))-1] of [(18)F]FPWAY was decreased to 32% of the ratio of [(18)F]FCWAY, indicating that [(18)F]FPWAY has lower affinity than [(18)F]FCWAY. The 5-HT(1A)R selectivity of [(18)F]FPWAY was confirmed using ex vivo autoradiography studies with 5-HT(1A)R knockout, heterozygous, and wildtype mice.Pre- or post-treatment of awake rodents in tissue dissection studies with paroxetine had no effect on hippocampal binding of [(18)F]FCWAY or [(18)F]FPWAY compared to controls, indicating neither tracer was sensitive to changes in endogenous 5-HT. In mouse ex vivo autoradiography studies in which awake mice were treated with fenfluramine following the [(18)F]FPWAY, a significant decrease was not observed in the hippocampus specific binding ratios. In rat dissection studies with fenfluramine administered following [(18)F]FPWAY or [(18)F]FBWAY ([(18)F]-MPPF) in awake or urethane-anesthetized rats, no significant differences in the specific binding ratios of the hippocampus were observed compared to their respective controls. [(18)F]FPWAY and [(18)F]FBWAY uptakes in all brain regions were increased variably in the anesthetized group (with the greatest increase in the hippocampus) vs. the awake group, but were decreased in the fenfluramine-treated anesthetized group vs. the anesthetized group. These data are best explained by changes in blood flow caused by urethane and fenfluramine, which varies from region to region in the brain. PMID:16440292

  15. Compositions and methods related to serotonin 5-HT1A receptors

    DOEpatents

    Mukherjee, Jogeshwar; Saigal, Neil; Saigal, legal representative, Harsh

    2012-09-25

    Contemplated substituted arylpiperazinyl compounds, and most preferably 18F-Mefway, exhibit desirable in vitro and in vivo binding characteristics to the 5-HT1A receptor. Among other advantageous parameters, contemplated compounds retain high binding affinity, display optimal lipophilicity, and are radiolabeled efficiently with 18F-fluorine in a single step. Still further, contemplated compounds exhibit high target to non-target ratios in receptor-rich regions both in vitro and in vivo, and selected compounds can be effectively and sensitively displaced by serotonin, thus providing a quantitative tool for measuring 5-HT1A receptors and serotonin concentration changes in the living brain.

  16. Compositions and methods related to serotonin 5-HT1A receptors

    DOEpatents

    Mukherjee, Jogeshwar; Saigal, Neil

    2010-06-08

    Contemplated substituted arylpiperazinyl compounds, and most preferably 18F-Mefway, exhibit desirable in vitro and in vivo binding characteristics to the 5-HT1A receptor. Among other advantageous parameters, contemplated compounds retain high binding affinity, display optimal lipophilicity, and are radiolabeled efficiently with 18F-fluorine in a single step. Still further, contemplated compounds exhibit high target to non-target ratios in receptor-rich regions both in vitro and in vivo, and selected compounds can be effectively and sensitively displaced by serotonin, thus providing a quantitative tool for measuring 5-HT1A receptors and serotonin concentration changes in the living brain.

  17. Identification of serotonin 5-HT1A receptor partial agonists in ginger.

    PubMed

    Nievergelt, Andreas; Huonker, Peter; Schoop, Roland; Altmann, Karl-Heinz; Gertsch, Jürg

    2010-05-01

    Animal studies suggest that ginger (Zingiber officinale Roscoe) reduces anxiety. In this study, bioactivity-guided fractionation of a ginger extract identified nine compounds that interact with the human serotonin 5-HT(1A) receptor with significant to moderate binding affinities (K(i)=3-20 microM). [(35)S]-GTP gamma S assays indicated that 10-shogaol, 1-dehydro-6-gingerdione, and particularly the whole lipophilic ginger extract (K(i)=11.6 microg/ml) partially activate the 5-HT(1A) receptor (20-60% of maximal activation). In addition, the intestinal absorption of gingerols and shogaols was simulated and their interactions with P-glycoprotein were measured, suggesting a favourable pharmacokinetic profile for the 5-HT(1A) active compounds. PMID:20363635

  18. Platelet 5-HT(1A) receptor correlates with major depressive disorder in drug-free patients.

    PubMed

    Zhang, Zhang-Jin; Wang, Di; Man, Sui Cheung; Ng, Roger; McAlonan, Grainne M; Wong, Hei Kiu; Wong, Wendy; Lee, Jade; Tan, Qing-Rong

    2014-08-01

    The platelet serotonergic system has potential biomarker utility for major depressive disorder (MDD). In the present study, platelet expression of 5-HT1A receptors and serotonin transporter (SERT) proteins, and serotonin (5-HT) and its metabolite 5-hydroxyindoleacetic acid (5-HIAA) were quantified in 53 patients with MDD and 22 unaffected controls. All were drug-free, non-smokers and had no other psychiatric and cardiovascular comorbidity. The severity of depression symptoms was evaluated using the 17-item Hamilton Depression Rating Scale (HAMD-17) and the Self-rating Depression Scale (SDS). Patients with MDD had significantly higher expression of platelet 5-HT1A receptors but significantly lower contents of platelet 5-HT, platelet-poor plasma (PPP) 5-HT and PPP 5-HIAA compared to healthy controls, and this was correlated with the severity of depression. SERT expression did not differ between the two groups. Correlation analysis confirmed a strong, inverse relationship between the 5-HT1A receptor expression and the 5-HT and 5-HIAA levels. Thus overexpression of platelet 5-HT1A receptors and reduced 5-HT tone may function as a peripheral marker of depression.

  19. 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.

  20. Oleanolic acid acrylate elicits antidepressant-like effect mediated by 5-HT1A receptor.

    PubMed

    Fajemiroye, James O; Polepally, Prabhakar R; Chaurasiya, Narayan D; Tekwani, Babu L; Zjawiony, Jordan K; Costa, Elson A

    2015-01-01

    The development of new drugs for the treatment of depression is strategic to achieving clinical needs of patients. This study evaluates antidepressant-like effect and neural mechanisms of four oleanolic acid derivatives i.e. acrylate (D1), methacrylate (D2), methyl fumarate (D3) and ethyl fumarate (D4). All derivatives were obtained by simple one-step esterification of oleanolic acid prior to pharmacological screening in the forced swimming (FS) and open field (OF) tests. Pharmacological tools like α-methyl-p-tyrosine (AMPT, catecholamine depletor), p-chlorophenylalanine (serotonin depletor), prazosin (PRAZ, selective α1-receptor antagonist), WAY-100635 (selective serotonin 5-HT1A receptor antagonist) as well as monoamine oxidase (MAO) and functional binding assays were conducted to investigate possible neural mechanisms. In the FS test, D1 showed the most promising antidepressant-like effect without eliciting locomotor incoordination. Unlike group of mice pretreated with AMPT 100 mg/kg, PCPA 100 mg/kg or PRAZ 1 mg/kg, the effect of D1 was attenuated by WAY-100635 0.3 mg/kg pretreatment. D1 demonstrated moderate inhibition of MAO-A (IC50 = 48.848 ± 1.935 μM), potency (pEC50 = 6.1 ± 0.1) and intrinsic activity (E max = 26 ± 2.0%) on 5-HT1A receptor. In conclusion, our findings showed antidepressant-like effect of D1 and possible involvement of 5-HT1A receptor.

  1. 5-HT-1A receptor-mediated modulation of medullary expiratory neurones in the cat.

    PubMed Central

    Lalley, P M; Bischoff, A M; Richter, D W

    1994-01-01

    The involvement of the 5-HT-1A receptor in serotoninergic responses of stage 2 expiratory (E-2) neurones was investigated in pentobarbitone-anaesthetized, mechanically ventilated cats. The specific agonist of the 5-HT-1A receptor, 8-hydroxy-diproplaminotetralin (8-OH-DPAT), administered systemically or by ionophoresis directly on to the neurones, had a clear depressant effect. Administration of 8-OH-DPAT at doses of 10-50 micrograms kg-1 (I.V.) increased the membrane hyperpolarizations of E-2 neurones during the inspiratory and postinspiratory phases, and shortened their duration of activity in association with shortening of phrenic nerve activity. Discharges of E-2 neurones were also less intense. At doses of 50-90 micrograms kg-1, 8-OH-DPAT reduced or abolished inspiratory hyperpolarizations, and reduced expiratory depolarizations of membrane potential and discharge in parallel with inhibition of phrenic nerve discharges. The effects of the larger doses were reversed by I.V. injection of NAN-190, an antagonist at the 5-HT-1A receptor. Dose-dependent effects on the membrane potential and discharge of E-2 neurones, but not on phrenic nerve activity, were also seen by ionophoretic administration of 8-OH-DPAT on to E-2 neurones. At low currents, ejection of 8-OH-DPAT hyperpolarized the neurones without affecting the duration of inspiratory hyperpolarization and expiratory depolarization. This hyperpolarization depressed the intensity and the duration of expiratory discharges. Ejection with larger currents hyperpolarized the E-2 neurones further, and depressed expiratory depolarization leading to blockade of expiratory discharges. The effects on membrane potential were accompanied by decreased neuronal input resistance. This depressed the excitability of E-2 neurones as tested by discharge evoked by intracellular current injection. The amplitudes of action potentials decreased in parallel with the changes in input resistance. The effects were attributed to a

  2. Astroglial 5-HT1a receptors and S-100 beta in development and plasticity.

    PubMed

    Whitaker-Azmitia, P M; Azmitia, E C

    1994-01-01

    The work described in this article is concerned with the role of the 5-HT1a receptor in mediating the neurotrophic effects of serotonin, principally through the release of the substance S-100 beta from astroglial cells. These receptors are also present in astrocytes of the mature brain and may play a role in the synaptic plasticity necessary for certain experience-driven brain changes, such as memory or learning. The presence of these receptors on astroglial cells of the adult brain also has interesting implications for the mechanism of action of many psychotropic drugs acting through the serotonergic system. PMID:7850356

  3. Serotonin 5-HT1A receptors as targets for agents to treat psychiatric disorders: rationale and current status of research.

    PubMed

    Celada, Pau; Bortolozzi, Analía; Artigas, Francesc

    2013-09-01

    Psychiatric disorders represent a large economic burden in modern societies. However, pharmacological treatments are still far from optimal. Drugs used in the treatment of major depressive disorder (MDD) and anxiety disorders (selective serotonin [5-HT] reuptake inhibitors [SSRIs] and serotonin-noradrenaline reuptake inhibitors [SNRIs]) are pharmacological refinements of first-generation tricyclic drugs, discovered by serendipity, and show low efficacy and slowness of onset. Moreover, antipsychotic drugs are partly effective in positive symptoms of schizophrenia, yet they poorly treat negative symptoms and cognitive deficits. The present article reviews the neurobiological basis of 5-HT1A receptor (5-HT1A-R) function and the role of pre- and postsynaptic 5-HT1A-Rs in the treatment of MDD, anxiety and psychotic disorders. The activation of postsynaptic 5-HT1A-Rs in corticolimbic areas appears beneficial for the therapeutic action of antidepressant drugs. However, presynaptic 5-HT1A-Rs play a detrimental role in MDD, since individuals with high density or function of presynaptic 5-HT1A-Rs are more susceptible to mood disorders and suicide, and respond poorly to antidepressant drugs. Moreover, the indirect activation of presynaptic 5-HT1A-Rs by SSRIs/SNRIs reduces 5-HT neuron activity and terminal 5-HT release, thus opposing the elevation of extracellular 5-HT produced by blockade of the serotonin transporter (SERT) in the forebrain. Chronic antidepressant treatment desensitizes presynaptic 5-HT1A-Rs, thus reducing the effectiveness of the 5-HT1A autoreceptor-mediated negative feedback. The prevention of this process by the non-selective partial agonist pindolol accelerates clinical antidepressant effects. Two new antidepressant drugs, vilazodone (marketed in the USA) and vortioxetine (in development) incorporate partial 5-HT1A-R agonist properties with SERT blockade. Several studies with transgenic mice have also established the respective role of pre- and

  4. Oleanolic acid acrylate elicits antidepressant-like effect mediated by 5-HT1A receptor

    PubMed Central

    Fajemiroye, James O.; Polepally, Prabhakar R.; Chaurasiya, Narayan D.; Tekwani, Babu L.; Zjawiony, Jordan K.; Costa, Elson A.

    2015-01-01

    The development of new drugs for the treatment of depression is strategic to achieving clinical needs of patients. This study evaluates antidepressant-like effect and neural mechanisms of four oleanolic acid derivatives i.e. acrylate (D1), methacrylate (D2), methyl fumarate (D3) and ethyl fumarate (D4). All derivatives were obtained by simple one-step esterification of oleanolic acid prior to pharmacological screening in the forced swimming (FS) and open field (OF) tests. Pharmacological tools like α-methyl-p-tyrosine (AMPT, catecholamine depletor), p-chlorophenylalanine (serotonin depletor), prazosin (PRAZ, selective α1-receptor antagonist), WAY-100635 (selective serotonin 5-HT1A receptor antagonist) as well as monoamine oxidase (MAO) and functional binding assays were conducted to investigate possible neural mechanisms. In the FS test, D1 showed the most promising antidepressant-like effect without eliciting locomotor incoordination. Unlike group of mice pretreated with AMPT 100 mg/kg, PCPA 100 mg/kg or PRAZ 1 mg/kg, the effect of D1 was attenuated by WAY-100635 0.3 mg/kg pretreatment. D1 demonstrated moderate inhibition of MAO-A (IC50 = 48.848 ± 1.935 μM), potency (pEC50 = 6.1 ± 0.1) and intrinsic activity (Emax = 26 ± 2.0%) on 5-HT1A receptor. In conclusion, our findings showed antidepressant-like effect of D1 and possible involvement of 5-HT1A receptor. PMID:26199018

  5. 5-HT(1A)-like receptor activation inhibits abstinence-induced methamphetamine withdrawal in planarians.

    PubMed

    Rawls, Scott M; Shah, Hardik; Ayoub, George; Raffa, Robert B

    2010-10-29

    No pharmacological therapy is approved to treat methamphetamine physical dependence, but it has been hypothesized that serotonin (5-HT)-enhancing drugs might limit the severity of withdrawal symptoms. To test this hypothesis, we used a planarian model of physical dependence that quantifies withdrawal as a reduction in planarian movement. Planarians exposed to methamphetamine (10 μM) for 60 min, and then placed (tested) into drug-free water for 5 min, displayed less movement (i.e., withdrawal) than either methamphetamine-naïve planarians tested in water or methamphetamine-exposed planarians tested in methamphetamine. A concentration-related inhibition of withdrawal was observed when methamphetamine-exposed planarians were placed into a solution containing either methamphetamine and 5-HT (0.1-100 μM) or methamphetamine and the 5-HT(1A) receptor agonist 8-hydroxy-N,N-dipropyl-2-aminotetralin (8-OH-DPAT) (10, 20 μM). Planarians with prior methamphetamine exposure displayed enhanced withdrawal when tested in a solution of the 5-HT(1A) receptor antagonist N-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-N-(2-pyridyl)cyclohexanecarboxamide (WAY 100635) (1 μM). Methamphetamine-induced withdrawal was not affected by the 5-HT(2B/2C) receptor agonist meta-chlorophenylpiperazine (m-CPZ) (0.1-20 μM). These results provide pharmacological evidence that serotonin-enhancing drugs inhibit expression of methamphetamine physical dependence in an invertebrate model of withdrawal, possibly through a 5-HT(1A)-like receptor-dependent mechanism.

  6. The effects of chronic ethanol self-administration on hippocampal 5-HT1A receptors in monkeys

    PubMed Central

    Burnett, Elizabeth J.; Grant, Kathleen A.; Davenport, April T.; Hemby, Scott E.; Friedman, David P.

    2014-01-01

    BACKGROUND Chronic alcohol consumption reduces brain serotonin and alters the synaptic mechanisms involved in memory formation. Hippocampal 5-HT1A receptors modulate these mechanisms, but the neuroadaptive response of 5HT1A receptors to chronic alcohol self-administration is not well understood. METHODS Hippocampal tissue from monkeys that voluntarily self-administered ethanol for 12 months (n=9) and accompanying controls (n=8) were prepared for in vitro receptor autoradiography and laser capture microdissection. The 5-HT1A receptor antagonist, [3H]MPPF, and the agonist, [3H]8-OH-DPAT, were used to measure total and G-protein coupled 5-HT1A receptors respectively. The expression of the genes encoding the 5-HT1A receptor and its trafficking protein Yif1B was measured in microdissected dentate gyrus (DG) granule cells and CA1 pyramidal neurons. RESULTS An increase in G-protein coupled, but not total, receptors was observed in the posterior pyramidal cell layer of CA1 in ethanol drinkers compared to controls. Chronic ethanol self-administration was also associated with an up-regulation of total and G-protein coupled 5-HT1A receptors in the posterior DG polymorphic layer. Changes in receptor binding were not associated with concomitant changes in 5-HT1A receptor mRNA expression. Chronic ethanol self-administration was associated with a significant increase in Yif1B gene expression in posterior CA1 pyramidal neurons. CONCLUSIONS Chronic, ethanol self-administration up-regulates hippocampal 5-HT1A receptor density in a region-specific manner that does not appear to be due to alterations at the level of transcription but instead may be due to increased receptor trafficking. Further exploration of the mechanisms mediating chronic ethanol-induced 5-HT1A receptor up-regulation and how hippocampal neurotransmission is altered is warranted. PMID:24467872

  7. Asymmetric Clustering Index in a Case Study of 5-HT1A Receptor Ligands

    PubMed Central

    Śmieja, Marek; Warszycki, Dawid; Tabor, Jacek; Bojarski, Andrzej J.

    2014-01-01

    The automatic clustering of chemical compounds is an important branch of chemoinformatics. In this paper the Asymmetric Clustering Index (Aci) is proposed to assess how well an automatically created partition reflects the reference. The asymmetry allows for a distinction between the fixed reference and the numerically constructed partition. The introduced index is applied to evaluate the quality of hierarchical clustering procedures for 5-HT1A receptor ligands. We find that the most appropriate combination of parameters for the hierarchical clustering of compounds with a determined activity for this biological target is the Klekota Roth fingerprint combined with the complete linkage function and the Buser similarity metric. PMID:25019251

  8. Drug-induced defaecation in rats: role of central 5-HT1A receptors.

    PubMed Central

    Croci, T.; Landi, M.; Bianchetti, A.; Manara, L.

    1995-01-01

    1. We investigated the acute effects of 5-hydroxytryptamine (5-HT), and of the 5-HT1A receptor agonists, 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT), buspirone and SR 57746A, on rat faecal pellet output and water content. 2. 5-HT, 8-OH-DPAT, buspirone and SR 57746A, a new selective 5-HT1A receptor agonist, displaced [3H]-8-OH-DPAT from specific binding sites in rat hippocampus membranes (Ki, nM; 1.8, 1.2, 15, 3.1 respectively) and stimulated rat defaecation dose-dependently. SR 57746A and buspirone induced 1 g dry weight of faeces at 1.3 and 6.1 mg kg-1, p.o. (AD1) respectively. 8-OH-DPAT and 5-HT stimulated defaecation after s.c. injection (AD1, 0.07 and 7.5 mg kg-1, respectively). All these agents increased faecal water content. 3. The putative 5-HT1A receptor antagonist, pindolol, injected s.c. or i.c.v., significantly reduced the defaecation induced by systemically administered 8-OH-DPAT, buspirone or SR 57746A, but not 5-HT. 4. Pretreatment with p-chlorophenylalanine (i.p.) or 5,7-dihydroxytryptamine (i.c.v.), according to protocols designed to cause either generalized or CNS-limited 5-HT depletion respectively, also reduced the defaecation induced by buspirone or SR 57746A. 5. No specific 5-HT1A binding sites could be labelled by incubating rat colon membranes with [3H]-8-OH-DPAT, and in vitro preparations of rat colon segments showed no response to 8-OH-DPAT or SR 57746A up to 5 microM. 6. After eight days' repeated daily treatment, complete tolerance developed to the stimulant effects of SR 57746A and buspirone on faecal water content, but not on faecal pellet output.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7647978

  9. New insight into the therapeutic role of 5-HT1A receptors in central nervous system disorders.

    PubMed

    Ohno, Yukihiro

    2010-06-01

    The serotonergic system plays a crucial role in regulating psychoemotional, cognitive and motor functions in the central nervous system (CNS). Among 5-HT receptor subtypes, 5-HT(1A) receptors have long been implicated in the pathogenesis and treatment of anxiety and depressive disorders. 5-HT(1A) receptors function as both presynaptic (autoreceptor) and postsynaptic receptors in specific brain regions such as the limbic areas, septum and raphe nuclei. 5-HT(1A) receptors negatively regulate cAMP-dependent signal transduction and inhibit neuronal activity by opening G-protein-gated inwardly rectifying potassium channels. The therapeutic action of 5-HT(1A) agonists and their mechanism in alleviating anxiety and depressive disorders have been well documented. In addition, recent studies have revealed new insights into the therapeutic role of 5-HT(1A) receptors in treating various CNS disorders, including not only depressive disorders (e.g., delayed onset of action and refractory symptoms), but also schizophrenia (e.g., cognitive impairment and antipsychotic-induced extrapyramidal side effects) and Parkinson's disease (e.g., extrapyramidal motor symptoms and L-DOPA-induced dyskinesia). These lines of evidences encourage us to design new generation 5-HT(1A) ligands such as 5-HT(1A) agonists with greater potency, higher selectivity and improved pharmacokinetic properties, and 5-HT(1A) ligands which combine multiple pharmacological actions (e.g., inhibition of serotonin transporter, dopamine D(2) receptors and other 5-HT receptor subtypes). Such new 5-HT(1A) ligands may overcome clinical efficacy limitations and/or improve adverse reactions in current CNS therapies.

  10. Serotonin decreases aggression via 5-HT1A receptors in the fighting fish Betta splendens.

    PubMed

    Clotfelter, Ethan D; O'Hare, Erin P; McNitt, Meredith M; Carpenter, Russ E; Summers, Cliff H

    2007-01-01

    The role of the monoamine neurotransmitter serotonin (5-HT) in the modulation of conspecific aggression in the fighting fish (Betta splendens) was investigated using pharmacological manipulations. We used a fish's response to its mirror image as our index of aggressive behavior. We also investigated the effects of some manipulations on monoamine levels in the B. splendens brain. Acute treatment with 5-HT and with the 5-HT1A receptor agonist 8-OH-DPAT both decreased aggressive behavior; however, treatment with the 5-HT1A receptor antagonist WAY-100635 did not increase aggression. Chronic treatment with the selective serotonin reuptake inhibitor fluoxetine caused no significant changes in aggressive behavior and a significant decline in 5-HT and 5-hydroxyindoleacetic acid (5-HIAA) concentrations. Treatment with the serotonin synthesis inhibitor p-chlorophenylalanine resulted in no change in aggression, yet serotonergic activity decreased significantly. Finally, a diet supplemented with L-tryptophan (Trp), the precursor to 5-HT, showed no consistent effects on aggressive behavior or brain monoamine concentrations. These results suggest a complex role for serotonin in the expression of aggression in teleost fishes, and that B. splendens may be a useful model organism in pharmacological and toxicological studies.

  11. Serotonin decreases aggression via 5-HT1A receptors in the fighting fish Betta splendens.

    PubMed

    Clotfelter, Ethan D; O'Hare, Erin P; McNitt, Meredith M; Carpenter, Russ E; Summers, Cliff H

    2007-01-01

    The role of the monoamine neurotransmitter serotonin (5-HT) in the modulation of conspecific aggression in the fighting fish (Betta splendens) was investigated using pharmacological manipulations. We used a fish's response to its mirror image as our index of aggressive behavior. We also investigated the effects of some manipulations on monoamine levels in the B. splendens brain. Acute treatment with 5-HT and with the 5-HT1A receptor agonist 8-OH-DPAT both decreased aggressive behavior; however, treatment with the 5-HT1A receptor antagonist WAY-100635 did not increase aggression. Chronic treatment with the selective serotonin reuptake inhibitor fluoxetine caused no significant changes in aggressive behavior and a significant decline in 5-HT and 5-hydroxyindoleacetic acid (5-HIAA) concentrations. Treatment with the serotonin synthesis inhibitor p-chlorophenylalanine resulted in no change in aggression, yet serotonergic activity decreased significantly. Finally, a diet supplemented with L-tryptophan (Trp), the precursor to 5-HT, showed no consistent effects on aggressive behavior or brain monoamine concentrations. These results suggest a complex role for serotonin in the expression of aggression in teleost fishes, and that B. splendens may be a useful model organism in pharmacological and toxicological studies. PMID:17553555

  12. The 5-HT1A receptor agonist flesinoxan shares discriminative stimulus properties with some 5-HT2 receptor antagonists.

    PubMed

    Herremans, A H; van der Heyden, J A; van Drimmelen, M; Olivier, B

    1999-10-01

    Ten homing pigeons were trained to discriminate the selective 5-HT1A receptor agonist flesinoxan (0.25 mg/kg p.o.) from its vehicle in a fixed-ratio (FR) 30 two-key operant drug discrimination procedure. The 5-HT2 receptor antagonist mianserin (ED50 = 4.8 mg/kg) fully substituted for flesinoxan, whereas ketanserin, ritanserin, mesulergine, and SB200646A substituted only partially, suggesting an interaction between 5-HT1A and 5-HT2 receptors. However, the 5-HT2 receptor agonists [DOI (0.6 mg/kg), TFMPP (10 mg/kg), mCPP (4 mg/kg)] were unable to antagonize the flesinoxan cue. The 5-HT1A receptor antagonists DU125530 (0.5-13 mg/kg) and WAY100,635 (0.1-1 mg/kg) partially antagonized the generalization of mianserin to flesinoxan. Taken together, these results are in accordance with the hypothesis that 5-HT1A receptor activation exerts an inhibitory effect on activation of 5-HT2 receptors. These results are in broad agreement with existing theories on 5-HT1A and 5-HT2 receptor interaction. Furthermore, it is argued that the discriminative stimulus properties of a drug may undergo qualitative changes with prolonged training.

  13. 5-HT1a receptor antagonists block perforant path-dentate LTP induced in novel, but not familiar, environments

    PubMed Central

    Sanberg, Cyndy Davis; Jones, Floretta L.; Do, Viet H.; Dieguez, Dario; Derrick, Brian E.

    2006-01-01

    Numerous studies suggest roles for monoamines in modulating long-term potentiation (LTP). Previously, we reported that both induction and maintenance of perforant path-dentate gyrus LTP is enhanced when induced while animals explore novel environments. Here we investigate the contribution of serotonin and 5-HT1a receptors to the novelty-mediated enhancement of LTP. In freely moving animals, systemic administration of the selective 5-HT1a antagonist WAY-100635 (WAY) attenuated LTP in a dose-dependent manner when LTP was induced while animals explored novel cages. In contrast, LTP was completely unaffected by WAY when induced in familiar environments. LTP was also blocked in anesthetized animals by direct application of WAY to the dentate gyrus, but not to the median raphe nucleus (MRN), suggesting the effect of systemic WAY is mediated by a block of dentate 5-HT1a receptors. Paradoxically, systemic administration of the 5-HT1a agonist 8-OH-DPAT also attenuated LTP. This attenuation was mimicked in anesthetized animals following application of 8-OH-DPAT to the MRN, but not the dentate gyrus. In addition, application of a 5-HT1a agonist to the dentate gyrus reduced somatic GABAergic inhibition. Because serotonergic projections from the MRN terminate on dentate inhibitory interneurons, these data suggest 5-HT1a receptors contribute to LTP induction via inhibition of GABAergic interneurons. Moreover, activation of raphe 5-HT1a autoreceptors, which inhibits serotonin release, attenuated LTP induction even in familiar environments. This suggests that serotonin normally contributes to dentate LTP induction in a variety of behavioral states. Together, these data suggest that serotonin and dentate 5-HT1a receptors play a permissive role in dentate LTP induction, particularly in novel conditions, and presumably, during the encoding of novel, hippocampus-relevant information. PMID:16452654

  14. Cannabidiol blocks long-lasting behavioral consequences of predator threat stress: possible involvement of 5HT1A receptors.

    PubMed

    Campos, Alline Cristina; Ferreira, Frederico Rogério; Guimarães, Francisco Silveira

    2012-11-01

    Posttraumatic stress disorder (PTSD) is an incapacitating syndrome that follows a traumatic experience. Predator exposure promotes long-lasting anxiogenic effect in rodents, an effect related to symptoms found in PTSD patients. Cannabidiol (CBD) is a non-psychotomimetic component of Cannabis sativa with anxiolytic effects. The present study investigated the anti-anxiety actions of CBD administration in a model of PTSD. Male Wistar rats exposed to a predator (cat) received, 1 h later, singled or repeated i.p. administration of vehicle or CBD. Seven days after the stress animals were submitted to the elevated plus maze. To investigate the involvement of 5HT1A receptors in CBD effects animals were pre-treated with WAY100635, a 5HT1A receptor antagonist. To explore possible neurobiological mechanisms involved in these effects, 5HT1A receptor mRNA and BDNF protein expression were measured in the hippocampus, frontal cortex, amygdaloid complex and dorsal periaqueductal gray. Repeated administration of CBD prevented long-lasting anxiogenic effects promoted by a single predator exposure. Pretreatment with WAY100635 attenuated CBD effects. Seven days after predator exposure 5HT1A mRNA expression was up regulated in the frontal cortex and hippocampus. CBD and paroxetine failed to prevent this effect. No change in BDNF expression was found. In conclusion, predator exposure promotes long-lasting up-regulation of 5HT1A receptor gene expression in the hippocampus and frontal cortex. Repeated CBD administration prevents the long-lasting anxiogenic effects observed after predator exposure probably by facilitating 5HT1A receptors neurotransmission. Our results suggest that CBD has beneficial potential for PTSD treatment and that 5HT1A receptors could be a therapeutic target in this disorder.

  15. On the role of 5-HT(1A) receptor gene in behavioral effect of brain-derived neurotrophic factor.

    PubMed

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

    2014-08-01

    Experiments were made on a congenic AKR.CBA-D13Mit76C (76C) mouse strain created by transferring a chromosome 13 fragment containing the 5-HT1A receptor gene from a CBA strain to an AKR background. It was shown that 76C mice differed from AKR mice by decreased 5-HT1A receptor and tryptophan hydroxylase-2 (tph-2) genes expression in the midbrain. Functional activity of 5-HT2A receptors and 5-HT(2A) receptor mRNA levels in the midbrain and hippocampus of 76C mice were decreased compared with AKR mice. Central brain-derived neurotrophic factor (BDNF) administration (300 ng i.c.v.) reduced 5-HT1A and 5-HT(2A) receptor mRNA levels in the frontal cortex and tph-2 mRNA level in the midbrain of AKR mice. However, BDNF failed to produce any effect on the expression of 5-HT(1A) , 5-HT(2A) , and tph-2 genes in 76C mice but decreased functional activity of 5-HT(2A) receptors in 76C mice and increased it in AKR mice. BDNF restored social deficiency in 76C mice but produced asocial behavior (aggressive attacks towards young mice) in AKR mice. The data indicate that a small genetic variation altered the response to BDNF and show an important role of 5-HT(1A) receptor gene in the 5-HT system response to BDNF treatment and in behavioral effects of BDNF.

  16. Involvement of the 5-HT(1A) receptor in the anti-immobility effects of fluvoxamine in the forced swimming test and mouse strain differences in 5-HT(1A) receptor binding.

    PubMed

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

    2010-03-10

    We previously demonstrated the presence of strain differences in baseline immobility time and sensitivity to the selective serotonin reuptake inhibitor (SSRI) fluvoxamine in five strains of mice (ICR, ddY, C57BL, DBA/2 and BALB/c mice). Furthermore, variations in serotonin (5-HT) transporter binding in the brain were strongly related to strain differences in baseline immobility and sensitivity to fluvoxamine. In the present study, we examined the involvement of the 5-HT(1A) receptor in anti-immobility effects in DBA/2 mice, which show high sensitivity to fluvoxamine. The anti-immobility effects of fluvoxamine in DBA/2 mice were inhibited by the 5-HT(1A) receptor antagonist N-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-N-(2-pyridinyl)cyclohexanecarboxamide (WAY 100635). However, the 5-HT(1B) receptor antagonist 3-[3-(dimethylamino)propyl]-4-hydroxy-N-[4-(4-pyridinyl)phenyl]benzamide (GR55562), the 5-HT(2) receptor antagonist 6-methyl-1-(methylethyl)-ergoline-8beta-carboxylic acid 2-hydroxy-1-methylpropyl ester (LY 53857), the 5-HT(3) receptor antagonist ondansetron and the 5-HT(4) receptor antagonist 4-amino-5-chloro-2-methoxy-benzoic acid 2-(diethylamino)ethyl ester (SDZ 205,557) did not influence the anti-immobility effects of fluvoxamine in DBA/2 mice. These results suggest that fluvoxamine-induced antidepressant-like effects in DBA/2 mice are mediated by the 5-HT(1A) receptor. We analyzed 5-HT(1A) receptor binding in the brains of five strains of mice. Strain differences in 5-HT(1A) receptor binding were observed. 5-HT(1A) receptor binding in brain was not correlated with baseline immobility time in the five strains of mice examined. These results suggest that, although the anti-immobility effects of fluvoxamine in DBA/2 mice are mediated by the 5-HT(1A) receptor, strain differences in 5-HT(1A) receptor binding are not related to variation in immobility time and responses to fluvoxamine.

  17. High-level stable expression of recombinant 5-HT1A 5-hydroxytryptamine receptors in Chinese hamster ovary cells.

    PubMed Central

    Newman-Tancredi, A; Wootton, R; Strange, P G

    1992-01-01

    The human 5-hydroxytryptamine 5-HT1A receptor gene was transfected into Chinese hamster ovary cells. A series of recombinant monoclonal cell lines expressing the receptor were isolated and the properties of one cell line that expressed receptors at a high level (2.8 pmol/mg) were studied in detail. In ligand binding assays with the selective 5-HT1A receptor agonist 2-(NN-di[3H]propylamino)-8-hydroxy-1,2,3,4-tetrahydronaphthalene ([3H]8-OH-DPAT) only a single class of saturable high-affinity binding sites was detected, with a pharmacological profile in competition experiments essentially identical to that of the 5-HT1A receptor of bovine hippocampus. [3H]8-OH-DPAT binding to the recombinant cell membranes was inhibited by GTP, showing that the receptors in the transfected cells couple to G-proteins. A series of 5-hydroxytryptamine agonists inhibited forskolin-stimulated adenylate cyclase activity in the cells and, despite the high level of receptor expression, their apparent efficacies were similar to those observed for inhibition of adenylate cyclase in brain. This recombinant cell line provides a complete model system for studying the 5-HT1A receptor and its transmembrane signalling system. The recombinant cells can also be grown in suspension culture for long periods but, whereas 5-HT1A receptor numbers and receptor regulation by guanine nucleotides are maintained in suspension-grown cells, the inhibition of adenylate cyclase by the 5-HT1A receptor is gradually lost. Images Fig. 1. PMID:1386736

  18. Cannabidiol injected into the bed nucleus of the stria terminalis modulates baroreflex activity through 5-HT1A receptors.

    PubMed

    Alves, Fernando H F; Crestani, Carlos C; Gomes, Felipe V; Guimarães, Francisco S; Correa, Fernando M A; Resstel, Leonardo B M

    2010-09-01

    Cannabidiol (CBD) is a non-psychotomimetic constituent of the Cannabis sativa plant that inhibits behavioral and cardiovascular responses to aversive situations, facilitating 5-HT1A-mediated neurotransmission. Previous results from our group suggest that the bed nucleus of the stria terminalis (BNST) may be involved in CBD's anti-aversive effects. To investigate whether the cardiovascular effects of the CBD could involve a direct drug effect on the BNST, we evaluated the effects of CBD microinjection into this structure on baroreflex activity. We also verified whether these effects were mediated by the activation of 5-HT(1A) receptors. Bilateral microinjection of CBD (60 nmol/100 nL) into the BNST increased the bradycardiac response to arterial pressure increases. However, no changes were observed in tachycardiac responses evoked by arterial pressure decreases. Pretreatment of the BNST with the selective 5-HT(1A) receptor antagonist WAY100635 (0.37 nmol/100 nL) prevented CBD effects on the baroreflex activity. Moreover, microinjection of the 5-HT(1A) receptor agonist 8-OH-DPAT (4 nmol/100 nL) caused effects that were similar to those observed after the microinjection of CBD, which were also blocked by pretreatment with WAY100635. In conclusion, the present studies show that the microinjection of CBD into the BNST has a facilitatory influence on the baroreflex response to blood pressure increases, acting through the activation of 5-HT1A receptors. PMID:20621717

  19. [(3)H]-F13640, a novel, selective and high-efficacy serotonin 5-HT(1A) receptor agonist radioligand.

    PubMed

    Heusler, Peter; Palmier, Christiane; Tardif, Stéphanie; Bernois, Sophie; Colpaert, Francis C; Cussac, Didier

    2010-10-01

    F13640 is a selective and high-efficacy serotonin 5-HT(1A) receptor agonist that demonstrates outstanding analgesic potential in different animal models. Here, we use the radiolabelled compound to further characterise its binding properties at 5-HT(1A) receptors. F13640 was tritium-labelled to 47 and 64 Ci/mmol specific activity and used as radioligand at membrane preparations of CHO cells expressing human (h) 5-HT(1A) receptors. The K (d) of [(3)H]-F13640 was 1.8 nM at h5-HT(1A) receptors as determined from saturation binding experiments. In association time-course experiments, k (obs) of [(3)H]-F13640 was 0.06 min(-1). Dissociation experiments performed in the presence of unlabelled F13640 as competing ligand yielded a k (off) value of 0.05 min(-1), resulting in a calculated K (d) of 1.4 nM. In comparison, [(3)H]-8-OH-DPAT had a k (obs) of 0.50 min(-1), a k (off) of 0.25 min(-1) and a calculated K (d) of 0.37 nM. Surprisingly, [(3)H]-F13640 dissociation kinetics were distinctly slower in the presence of WAY-100635 and spiperone as competing ligands when compared with the agonist competitors, F13640 and (+)8-OH-DPAT. The competitive binding profile of [(3)H]-F13640 with eight chemically diverse 5-HT(1A) receptor agonists and antagonists correlated highly (r = 0.996) with that of [(3)H]-8-OH-DPAT. In conclusion, [(3)H]-F13640 is a potent agonist radioligand at 5-HT(1A) receptors and may be a useful tool in pharmacological studies at native and recombinant 5-HT(1A) receptors. In addition, [(3)H]-F13640 dissociates more slowly from h5-HT(1A) receptors than [(3)H]-8-OH-DPAT, a kinetic property that might be related to its powerful analgesic effects as observed in vivo.

  20. 5-HT1A receptors of the nucleus tractus solitarii facilitate sympathetic recovery following hypotensive hemorrhage in rats

    PubMed Central

    Vantrease, Jaime E.; Dudek, Nichole; DonCarlos, Lydia L.

    2015-01-01

    The role of serotonin in the hemodynamic response to blood loss remains controversial. Caudal raphe serotonin neurons are activated during hypotensive hemorrhage, and their destruction attenuates sympathetic increases following blood loss in unanesthetized rats. Caudal raphe neurons provide serotonin-positive projections to the nucleus tractus solitarii (NTS), and disruption of serotonin-positive nerve terminals in the NTS attenuates sympathetic recovery following hemorrhage. Administration of 5-HT1A-receptor agonists following hemorrhage augments sympathetic-mediated increases in venous tone and tissue hypoxia. These findings led us to hypothesize that severe blood loss promotes activation of 5-HT1A receptors in the NTS, which facilitates sympathetic recovery and peripheral tissue perfusion. Here, we developed an adeno-associated viral vector encoding an efficacious small hairpin RNA sequence targeting the rat 5-HT1A receptor. Unanesthetized rats subjected to NTS injection of the anti-rat 5-HT1A small hairpin RNA-encoding vector 4 wk prior showed normal blood pressure recovery, but an attenuated recovery of renal sympathetic nerve activity (−6.4 ± 12.9 vs. 42.6 ± 15.6% baseline, P < 0.05) 50 min after 21% estimated blood volume withdrawal. The same rats developed increased tissue hypoxia after hemorrhage, as indicated by prolonged elevations in lactate (2.77 ± 0.5 vs. 1.34 ± 0.2 mmol/l, 60 min after start of hemorrhage, P < 0.05). 5-HT1A mRNA levels in the commissural NTS were directly correlated with renal sympathetic nerve activity (P < 0.01) and inversely correlated with lactate (P < 0.05) 60 min after start of hemorrhage. The data suggest that 5-HT1A receptors in the commissural NTS facilitate tissue perfusion after blood loss likely by increasing sympathetic-mediated venous return. PMID:25980022

  1. Activation of 5-HT1A receptors in the rat basolateral amygdala induces both anxiolytic and antipanic-like effects.

    PubMed

    Strauss, Christiana Villela de Andrade; Vicente, Maria Adrielle; Zangrossi, Helio

    2013-06-01

    The relevance of 5-HT1A and 5-HT2C receptors of the basolateral nucleus of the amygdala (BLA) in the mediation of anxiety-related defensive responses has long been acknowledged. Whereas strong evidence supports that activation of the latter receptors provokes anxiety, conflicting findings have been reported on the role played by the former binding site. In this study we further investigated the involvement of 5-HT1A receptors (5-HT1A-Rs) in the regulation of anxiety- and panic-related defensive behaviors. The results showed that intra-BLA injection of the 5-HT1A-R agonist 8-OH-DPAT (0.4-16nmol) in male Wistar rats impaired the acquisition of inhibitory avoidance in the elevated T-maze, increased the percentage of time spent in the lit compartment of the light-dark transition model and enhanced the number of punished drinking events in the Vogel conflict test, all changes compatible with an anxiolytic effect. This agonist also impaired escape expression in the elevated T-maze, suggestive of a panicolytic-like effect. 8-OH-DPAT-induced changes in the elevated T-maze and light-dark tests were blocked by previous local administration of the 5-HT1A-R antagonist WAY-100635 (0.37nmol) and were also observed after intra-BLA microinjection of the benzodiazepine receptor agonist midazolam (10-40nmol). Thus, stimulation of 5-HT1A-Rs in the BLA causes both anxiolytic- and panicolytic-like effects, what may have implications for the pathophysiology and treatment of generalized anxiety and panic disorders.

  2. Effects of dominance status on conditioned defeat and expression of 5-HT1A and 5-HT2A receptors

    PubMed Central

    Morrison, Kathleen E.; Swallows, Cody L.; Cooper, Matthew A.

    2011-01-01

    Past experience can alter how individuals respond to stressful events. The brain serotonin system is a key factor modulating stress-related behavior and may contribute to individual variation in coping styles. In this study we investigated whether dominant and subordinate hamsters respond differently to social defeat and whether their behavioral responses are associated with changes in 5-HT1A and 5-HT2A receptor immunoreactivity in several limbic brain regions. We paired weight-matched hamsters in daily aggressive encounters for two weeks so that they formed a stable dominance relationship. We also included controls that were exposed to an empty cage each day for two weeks. Twenty-four hours after the final pairing or empty cage exposure, subjects were socially defeated in 3, 5-min encounters with a more aggressive hamster. Twenty-four hours after social defeat, animals were tested for conditioned defeat in a 5-min social interaction test with a non-aggressive intruder. We collected brains following conditioned defeat testing and performed immunohistochemistry for 5-HT1A and 5-HT2A receptors. We found that dominants showed less submissive and defensive behavior at conditioned defeat testing compared to both subordinates and controls. Additionally, both dominants and subordinates had an increased number of 5-HT1A immunopositive cells in the basolateral amygdala compared to controls. Subordinates also had more 5-HT1A immunopositive cells in the dorsal medial amygdala than did controls. Finally, dominants had fewer 5-HT1A immunopositive cells in the paraventricular nucleus of the hypothalamus compared to controls. Our results indicate that dominant social status results in a blunted conditioned defeat response and a distinct pattern of 5-HT1A receptor expression, which may contribute to resistance to conditioned defeat. PMID:21362435

  3. Effects of dominance status on conditioned defeat and expression of 5-HT1A and 5-HT2A receptors.

    PubMed

    Morrison, Kathleen E; Swallows, Cody L; Cooper, Matthew A

    2011-08-01

    Past experience can alter how individuals respond to stressful events. The brain serotonin system is a key factor modulating stress-related behavior and may contribute to individual variation in coping styles. In this study we investigated whether dominant and subordinate hamsters respond differently to social defeat and whether their behavioral responses are associated with changes in 5-HT1A and 5-HT2A receptor immunoreactivity in several limbic brain regions. We paired weight-matched hamsters in daily aggressive encounters for two weeks so that they formed a stable dominance relationship. We also included controls that were exposed to an empty cage each day for two weeks. Twenty-four hours after the final pairing or empty cage exposure, subjects were socially defeated in 3, 5-min encounters with a more aggressive hamster. Twenty-four hours after social defeat, animals were tested for conditioned defeat in a 5-min social interaction test with a non-aggressive intruder. We collected brains following conditioned defeat testing and performed immunohistochemistry for 5-HT1A and 5-HT2A receptors. We found that dominants showed less submissive and defensive behavior at conditioned defeat testing compared to both subordinates and controls. Additionally, both dominants and subordinates had an increased number of 5-HT1A immunopositive cells in the basolateral amygdala compared to controls. Subordinates also had more 5-HT1A immunopositive cells in the dorsal medial amygdala than did controls. Finally, dominants had fewer 5-HT1A immunopositive cells in the paraventricular nucleus of the hypothalamus compared to controls. Our results indicate that dominant social status results in a blunted conditioned defeat response and a distinct pattern of 5-HT1A receptor expression, which may contribute to resistance to conditioned defeat.

  4. Selective serotonin 5-HT1A receptor biased agonists elicitdistinct brain activation patterns: a pharmacoMRI study

    PubMed Central

    Becker, G.; Bolbos, R.; Costes, N.; Redouté, J.; Newman-Tancredi, A.; Zimmer, L.

    2016-01-01

    Serotonin 1A (5-HT1A) receptors are involved in several physiological and pathological processes and constitute therefore an important therapeutic target. The recent pharmacological concept of biased agonism asserts that highly selective agonists can preferentially direct receptor signaling to specific intracellular responses, opening the possibility of drugs targeting a receptor subtype in specific brain regions. The present study brings additional support to this concept thanks to functional magnetic resonance imaging (7 Tesla-fMRI) in anaesthetized rats. Three 5-HT1A receptor agonists (8-OH-DPAT, F13714 and F15599) and one 5-HT1A receptor antagonist (MPPF) were compared in terms of influence on the brain blood oxygen level-dependent (BOLD) signal. Our study revealed for the first time contrasting BOLD signal patterns of biased agonists in comparison to a classical agonist and a silent antagonist. By providing functional information on the influence of pharmacological activation of 5-HT1A receptors in specific brain regions, this neuroimaging approach, translatable to the clinic, promises to be useful in exploring the new concept of biased agonism in neuropsychopharmacology. PMID:27211078

  5. 5-HT1a Receptor Antagonists Block Perforant Path-Dentate LTP Induced in Novel, but Not Familiar, Environments

    ERIC Educational Resources Information Center

    Sanberg, Cyndy Davis; Jones, Floretta L.; Do, Viet H.; Dieguez, Dario, Jr.; Derrick, Brian E.

    2006-01-01

    Numerous studies suggest roles for monoamines in modulating long-term potentiation (LTP). Previously, we reported that both induction and maintenance of perforant path-dentate gyrus LTP is enhanced when induced while animals explore novel environments. Here we investigate the contribution of serotonin and 5-HT1a receptors to the novelty-mediated…

  6. [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.

  7. Increased binding of 5-HT1A receptors in a dissociative amnesic patient after the recovery process.

    PubMed

    Kitamura, Soichiro; Yasuno, Fumihiko; Inoue, Makoto; Kosaka, Jun; Kiuchi, Kuniaki; Matsuoka, Kiwamu; Kishimoto, Toshifumi; Suhara, Tetsuya

    2014-10-30

    Dissociative amnesia is characterized by an inability to retrieve information already saved in memories. 5-HT has some role in neural regulatory control and may be related to the recovery from dissociative amnesia. To examine the role of 5-HT1A receptors in the recovery from dissociative amnesia, we performed two positron emission tomography (PET) scans on a 30-year-old patient of dissociative amnesia using [(11)C]WAY-100635, the first at amnesic state, and the second at the time he had recovered. Exploratory voxel-based analysis (VBA) was performed using SPM software. 5-HT1A BPND images were compared between the patient at amnesic and recovery states and healthy subjects (14 males, mean age 29.8 ± 6.45) with Jack-knife analysis. 5-HT1A receptor bindings of the patient at the recovery state were significantly higher than those of healthy subjects in the right superior and middle frontal cortex, left inferior frontal and orbitofrontal cortex and bilateral inferior temporal cortex. The increase in BPND values of recovery state was beyond 10% of those of amnesia state in these regions except in the right superior frontal cortex. We considered that neural regulatory control by the increase of 5-HT1A receptors in cortical regions played a role in the recovery from dissociative amnesia.

  8. 5-HT1A Receptor Activation Reduces Fear-related Behavior Following Social Defeat in Syrian Hamsters

    PubMed Central

    Bader, Lauren R.; Carboni, Joseph D.; Burleson, Cody A.; Cooper, Matthew A.

    2014-01-01

    Social defeat leads to selective avoidance of familiar opponents as well as general avoidance of novel, non-threatening intruders. Avoidance of familiar opponents represents a fear-related memory whereas generalized social avoidance indicates anxiety-like behavior. We have previously shown that serotonin signaling alters responses to social defeat in Syrian hamsters, although it is unclear whether serotonin modulates defeat-induced fear, anxiety, or both. In this study we focus on 5-HT1A receptors, in part, because their activation had been linked to the acquisition of conditioned fear. We hypothesized that pharmacological activation of 5-HT1A receptors prior to social defeat would reduce avoidance of familiar opponents, impair Arc expression in the basolateral amygdala (BLA), but not alter anxiety-like behavior. We administered 8-OH-DPAT, a 5-HT1A receptor agonist, prior to 3, 5-minute social defeats and 24-hours later exposed hamsters to a social interaction test to measure the conditioned defeat response immediately followed by either a Y-maze test or an open field test. In a separate experiment, we administered 8-OH-DPAT prior to 3, 5-minute social defeats and later removed brains for Arc immunohistochemistry. Social defeat increased the number of Arc immunopositive cells in the central amygdala (CeA), prelimbic cortex (PL), and BLA, and 8-OH-DPAT treatment reduced Arc immunoreactivity in the PL. These results suggest that 5-HT1A receptor activation impairs the fear memory associated with social defeat, but does not alter defeat-induced anxiety. Overall, 5-HT1A receptor activation may impair Arc expression in select brain regions such as the PL and thereby disrupt the development of a fear memory essential for the conditioned defeat response. PMID:24726709

  9. 5-HT1A receptor activation reduces fear-related behavior following social defeat in Syrian hamsters.

    PubMed

    Bader, Lauren R; Carboni, Joseph D; Burleson, Cody A; Cooper, Matthew A

    2014-07-01

    Social defeat leads to selective avoidance of familiar opponents as well as general avoidance of novel, non-threatening intruders. Avoidance of familiar opponents represents a fear-related memory whereas generalized social avoidance indicates anxiety-like behavior. We have previously shown that serotonin signaling alters responses to social defeat in Syrian hamsters, although it is unclear whether serotonin modulates defeat-induced fear, anxiety, or both. In this study we focus on 5-HT1A receptors, in part, because their activation had been linked to the acquisition of conditioned fear. We hypothesized that pharmacological activation of 5-HT1A receptors prior to social defeat would reduce avoidance of familiar opponents and impair Arc expression in the basolateral amygdala (BLA), but not alter anxiety-like behavior. We administered 8-OH-DPAT, a 5-HT1A receptor agonist, prior to 3, 5-minute social defeats and 24h later exposed hamsters to a social interaction test to measure the conditioned defeat response immediately followed by either a Y-maze test or an open field test. In a separate experiment, we administered 8-OH-DPAT prior to 3, 5-minute social defeats and later removed the brains for Arc immunohistochemistry. Social defeat increased the number of Arc immunopositive cells in the central amygdala (CeA), prelimbic cortex (PL), and BLA, and 8-OH-DPAT treatment reduced Arc immunoreactivity in the PL. These results suggest that 5-HT1A receptor activation impairs the fear memory associated with social defeat, but does not alter defeat-induced anxiety. Overall, 5-HT1A receptor activation may impair Arc expression in select brain regions such as the PL and thereby disrupt the development of a fear memory essential for the conditioned defeat response.

  10. HBK-7 - A new xanthone derivative and a 5-HT1A receptor antagonist with antidepressant-like properties.

    PubMed

    Pytka, Karolina; Kazek, Grzegorz; Siwek, Agata; Mordyl, Barbara; Głuch-Lutwin, Monika; Rapacz, Anna; Olczyk, Adrian; Gałuszka, Adam; Waszkielewicz, Anna; Marona, Henryk; Sapa, Jacek; Filipek, Barbara; Zygmunt, Małgorzata

    2016-01-01

    Xanthone derivatives possess many biological properties, including neuroprotective, antioxidant or antidepressant-like. In this study we aimed to investigate antidepressant- and anxiolytic-like properties of a new xanthone derivative - 6-methoxy-4-[4-(2-methoxyphenyl)piperazin-1-yl]-9H-xanthen-9-one (HBK-7), as well as its possible mechanism of action, and the influence on cognitive and motor function. HBK-7 in our earlier studies showed high affinity for serotonergic 5-HT1A receptor. We determined the affinity of HBK-7 for CNS receptors and transporters using radioligand assays and examined its intrinsic activity towards 5-HT1A receptor. We evaluated antidepressant- and anxiolytic-like activity of HBK-7 in the mouse forced swim test, and four-plate test, respectively. We examined the influence on locomotor activity in mice to determine if the effect observed in the forced swim test was specific. We used step-through passive avoidance and rotarod tests to evaluate the influence of HBK-7 on cognitive and motor function, respectively. HBK-7 showed moderate affinity for dopaminergic D2 receptor and very low for serotonergic 5-HT2A, adrenergic α2 receptors, as well as serotonin transporter. Functional studies revealed that HBK-7 was a 5-HT1A receptor antagonist. HBK-7 (10mg/kg) decreased immobility time in the forced swim test. Combined treatment with sub-effective doses of HBK-7 and fluoxetine reduced immobility of mice in the forced swim test. Pretreatment with p-chlorophenylalanine and WAY-100,635 antagonized the antidepressant-like effect of HBK-7. Neither of the treatments influenced locomotor activity of mice. HBK-7 at antidepressant-like dose did not impair memory or motor coordination in mice. We demonstrated that HBK-7 was a 5-HT1A receptor antagonist with potent, comparable to mianserin, antidepressant-like activity. HBK-7 mediated its effect through serotonergic system and its antidepressant-like action required the activation of 5-HT1A receptors. At active

  11. HBK-7 - A new xanthone derivative and a 5-HT1A receptor antagonist with antidepressant-like properties.

    PubMed

    Pytka, Karolina; Kazek, Grzegorz; Siwek, Agata; Mordyl, Barbara; Głuch-Lutwin, Monika; Rapacz, Anna; Olczyk, Adrian; Gałuszka, Adam; Waszkielewicz, Anna; Marona, Henryk; Sapa, Jacek; Filipek, Barbara; Zygmunt, Małgorzata

    2016-01-01

    Xanthone derivatives possess many biological properties, including neuroprotective, antioxidant or antidepressant-like. In this study we aimed to investigate antidepressant- and anxiolytic-like properties of a new xanthone derivative - 6-methoxy-4-[4-(2-methoxyphenyl)piperazin-1-yl]-9H-xanthen-9-one (HBK-7), as well as its possible mechanism of action, and the influence on cognitive and motor function. HBK-7 in our earlier studies showed high affinity for serotonergic 5-HT1A receptor. We determined the affinity of HBK-7 for CNS receptors and transporters using radioligand assays and examined its intrinsic activity towards 5-HT1A receptor. We evaluated antidepressant- and anxiolytic-like activity of HBK-7 in the mouse forced swim test, and four-plate test, respectively. We examined the influence on locomotor activity in mice to determine if the effect observed in the forced swim test was specific. We used step-through passive avoidance and rotarod tests to evaluate the influence of HBK-7 on cognitive and motor function, respectively. HBK-7 showed moderate affinity for dopaminergic D2 receptor and very low for serotonergic 5-HT2A, adrenergic α2 receptors, as well as serotonin transporter. Functional studies revealed that HBK-7 was a 5-HT1A receptor antagonist. HBK-7 (10mg/kg) decreased immobility time in the forced swim test. Combined treatment with sub-effective doses of HBK-7 and fluoxetine reduced immobility of mice in the forced swim test. Pretreatment with p-chlorophenylalanine and WAY-100,635 antagonized the antidepressant-like effect of HBK-7. Neither of the treatments influenced locomotor activity of mice. HBK-7 at antidepressant-like dose did not impair memory or motor coordination in mice. We demonstrated that HBK-7 was a 5-HT1A receptor antagonist with potent, comparable to mianserin, antidepressant-like activity. HBK-7 mediated its effect through serotonergic system and its antidepressant-like action required the activation of 5-HT1A receptors. At active

  12. Quantitative Structure-Activity Relationship for High Affinity 5-HT1A Receptor Ligands Based on Norm Indexes.

    PubMed

    Jia, Qingzhu; Cui, Xue; Li, Lei; Wang, Qiang; Liu, Ying; Xia, Shuqian; Ma, Peisheng

    2015-12-24

    Arylpiperazine derivatives are promising 5-hydroxytryptamine (5-HT) receptor ligands which can inhibit serotonin reuptake effectively. In this work, some norm index descriptors were proposed and further utilized to develop a model for predicting 5-HT1A receptor affinity (pKi) of 88 arylpiperazine derivatives. Results showed that this new model could provide satisfactory predictions with the square of the correction coefficient (R(2)) of 0.8891 and the squared correlation coefficient of cross-validation (Q(2)) of 0.8082, respectively. In addition, the applicability domain of this model was validated by using the leverage approach and results which suggested potential large scale for further utilization of this model. The results of statistical values and validation tests demonstrated that our proposed norm index based model could be successfully applied for predicting the affinity 5-HT1A receptor ligands of arylpiperazine derivatives.

  13. Mechanisms of cannabidiol neuroprotection in hypoxic-ischemic newborn pigs: role of 5HT(1A) and CB2 receptors.

    PubMed

    Pazos, M Ruth; Mohammed, Nagat; Lafuente, Hector; Santos, Martin; Martínez-Pinilla, Eva; Moreno, Estefania; Valdizan, Elsa; Romero, Julián; Pazos, Angel; Franco, Rafael; Hillard, Cecilia J; Alvarez, Francisco J; Martínez-Orgado, Jose

    2013-08-01

    The mechanisms underlying the neuroprotective effects of cannabidiol (CBD) were studied in vivo using a hypoxic-ischemic (HI) brain injury model in newborn pigs. One- to two-day-old piglets were exposed to HI for 30 min by interrupting carotid blood flow and reducing the fraction of inspired oxygen to 10%. Thirty minutes after HI, the piglets were treated with vehicle (HV) or 1 mg/kg CBD, alone (HC) or in combination with 1 mg/kg of a CB₂ receptor antagonist (AM630) or a serotonin 5HT(1A) receptor antagonist (WAY100635). HI decreased the number of viable neurons and affected the amplitude-integrated EEG background activity as well as different prognostic proton-magnetic-resonance-spectroscopy (H(±)-MRS)-detectable biomarkers (lactate/N-acetylaspartate and N-acetylaspartate/choline ratios). HI brain damage was also associated with increases in excitotoxicity (increased glutamate/N-acetylaspartate ratio), oxidative stress (decreased glutathione/creatine ratio and increased protein carbonylation) and inflammation (increased brain IL-1 levels). CBD administration after HI prevented all these alterations, although this CBD-mediated neuroprotection was reversed by co-administration of either WAY100635 or AM630, suggesting the involvement of CB₂ and 5HT(1A) receptors. The involvement of CB₂ receptors was not dependent on a CBD-mediated increase in endocannabinoids. Finally, bioluminescence resonance energy transfer studies indicated that CB₂ and 5HT(1A) receptors may form heteromers in living HEK-293T cells. In conclusion, our findings demonstrate that CBD exerts robust neuroprotective effects in vivo in HI piglets, modulating excitotoxicity, oxidative stress and inflammation, and that both CB₂ and 5HT(1A) receptors are implicated in these effects.

  14. The Role of 5-HT1A Receptors in Long-Term Adaptation of Newborn Rats to Hypoxia.

    PubMed

    Mikhailenko, V A; Butkevich, I P

    2016-08-01

    We studied the effects of neonatal hypoxia on adaptive behavior of rats during prepubertal and pubertal periods in the control and after repeated injections of 5-HT1A receptor agonist buspirone. Hypoxia enhanced the inflammatory nociceptive response and exacerbated the depressive-like behavior. Repeated injections of buspirone starting from the neonatal period produced a long-term normalizing effect on the inflammatory nociceptive response and psychoemotional behavior disturbed by hypoxia. The protective effect of buspirone can result from strengthening of the adaptive potencies of the serotoninergic system via activation of 5-HT1A receptors that up-regulate secretion of trophic factor S100β under conditions of serotonin deficiency typical of rats exposed to neonatal hypoxia. Buspirone promotes recovery of the afferent and efferent connections of the raphe nuclei with the prefrontal cortex and spinal cord involved in integration of the anti-nociceptive and psychoemotional systems. PMID:27591870

  15. Ipsapirone challenge in aggressive men shows an inverse correlation between 5-HT1A receptor function and aggression.

    PubMed

    Cleare, A J; Bond, A J

    2000-03-01

    Previous studies have suggested that 5-HT(1A) receptor function is linked to aggression. We studied 12 healthy men selected to have high trait levels of aggression. They filled in various self-rating measures of aggression, and underwent a double blind, crossover challenge with ipsapirone (20 mg orally) and a placebo. On both occasions, we measured the endocrine (ACTH, cortisol, growth hormone and prolactin), hypothermic and bodily symptom responses every 30 min for 180 min. We found that subjects with blunted neuroendocrine responses to the ipsapirone challenge had significantly higher self-ratings of aggression on a number of measures. The same relationship held using the bodily symptom response to ipsapirone: blunted responses were associated with higher ratings of aggression. We conclude that impaired 5-HT(1A) receptor function is associated with increased aggressiveness. PMID:10928305

  16. The antipsychotic aripiprazole induces antinociceptive effects: Possible role of peripheral dopamine D2 and serotonin 5-HT1A receptors.

    PubMed

    Almeida-Santos, Ana F; Ferreira, Renata C M; Duarte, Igor D; Aguiar, Daniele C; Romero, Thiago R L; Moreira, Fabricio A

    2015-10-15

    Aripiprazole is an antipsychotic that acts by multiple mechanisms, including partial agonism at dopamine D2 and serotonin 5-HT1A receptors. Since these neurotransmitters also modulate pain and analgesia, we tested the hypothesis that systemic or local administration of aripiprazole induces antinociceptive responses. Systemic aripiprazole (0.1-10 mg/kg; i.p.) injection in mice inhibited formalin-induced paw licking and PGE2-induced hyperalgesia in the paw pressure test. This effect was mimicked by intra-plantar administration (12.5-100 µg/paw) in the ipsi, but not contralateral, paw. The peripheral action of aripiprazole (100 µg/paw) was reversed by haloperidol (0.1-10 µg/paw), suggesting the activation of dopamine receptors as a possible mechanism. Accordingly, quinpirole (25-100 µg/paw), a full agonist at D2/D3 receptors, also reduced nociceptive responses.. In line with the partial agoniztic activity of aripiprazole, low dose of this compound inhibited the effect of quinpirole (both at 25 µg/paw). Finally, peripheral administration of NAN-190 (0.1-10 μg/paw), a 5-HT1A antagonist, also prevented aripiprazole-induced antinociception. In conclusion, systemic or local administration of aripiprazole induces antinociceptive effects. Similar to its antipsychotic activity, the possible peripheral mechanism involves dopamine D2 and serotoninergic 5-HT1A receptors. Aripiprazole and other dopaminergic modulators should be further investigated as new treatments for certain types of pain.

  17. 5-HT1A receptor-responsive pedunculopontine tegmental neurons suppress REM sleep and respiratory motor activity.

    PubMed

    Grace, Kevin P; Liu, Hattie; Horner, Richard L

    2012-02-01

    Serotonin type 1A (5-HT(1A)) receptor-responsive neurons in the pedunculopontine tegmental nucleus (PPTn) become maximally active immediately before and during rapid eye movement (REM) sleep. A prevailing model of REM sleep generation indicates that activation of such neurons contributes significantly to the generation of REM sleep, and if correct then inactivation of such neurons ought to suppress REM sleep. We test this hypothesis using bilateral microperfusion of the 5-HT(1A) receptor agonist 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT, 10 μm) into the PPTn; this tool has been shown to selectively silence REM sleep-active PPTn neurons while the activity of wake/REM sleep-active PPTn neurons is unaffected. Contrary to the prevailing model, bilateral microperfusion of 8-OH-DPAT into the PPTn (n = 23 rats) significantly increased REM sleep both as a percentage of the total recording time and sleep time, compared with both within-animal vehicle controls and between-animal time-controls. This increased REM sleep resulted from an increased frequency of REM sleep bouts but not their duration, indicating an effect on mechanisms of REM sleep initiation but not maintenance. Furthermore, an increased proportion of the REM sleep bouts stemmed from periods of low REM sleep drive quantified electrographically. Targeted suppression of 5-HT(1A) receptor-responsive PPTn neurons also increased respiratory rate and respiratory-related genioglossus activity, and increased the frequency and amplitude of the sporadic genioglossus activations occurring during REM sleep. These data indicate that 5-HT(1A) receptor-responsive PPTn neurons normally function to restrain REM sleep by elevating the drive threshold for REM sleep induction, and restrain the expression of respiratory rate and motor activities.

  18. The 5-HT(1A) receptor agonist F 13640 attenuates mechanical allodynia in a rat model of trigeminal neuropathic pain.

    PubMed

    Deseure, Kristof; Koek, Wouter; Colpaert, Francis C; Adriaensen, Hugo

    2002-12-01

    The effects of acute intraperitoneal injections of the 5-HT(1A) receptor agonists F 13640 [(3-chloro-4-fluoro-phenyl)-[4-fluoro-4-[[(5-methyl-pyridin-2-ylmethyl)-amino]-methyl]piperidin-1-yl]-methadone] and F 13714 [3-chloro-4-fluorophenyl-(4-fluoro-4-[[(5-methyl-6-methylamino-pyridin-2-ylmethyl)-amino]-methyl]-piperidin-1-yl-methanone] were studied in comparison with those of baclofen and morphine on responsiveness to von Frey hair stimulation after chronic constriction injury to the rat's infraorbital nerve (IoN-CCI). Following IoN-CCI, an ipsilateral hyperresponsiveness developed that remained stable in control rats throughout the period of drug testing. F 13640, F 13714, baclofen and morphine dose-dependently decreased the hyperresponsiveness; normalization of the response occurred at doses 0.63, 0.04, 5 and 10 mg/kg, respectively. Confirming earlier data, baclofen's effects further validate IoN-CCI as a model of trigeminal neuralgia. The effects of F 13640 and F 13714 are initial evidence that 5-HT(1A) receptor agonists produce profound analgesia in the IoN-CCI model. The present data extend recent evidence that high-efficacy 5-HT(1A) receptor activation constitutes a new mechanism of central analgesia the spectrum of which may also encompass trigeminal neuropathic pain. PMID:12450569

  19. Rectal antinociceptive properties of alverine citrate are linked to antagonism at the 5-HT1A receptor subtype.

    PubMed

    Coelho, A M; Jacob, L; Fioramonti, J; Bueno, L

    2001-10-01

    Serotonin (5-HT) is considered as a major mediator causing hyperalgesia and is involved in inflammatory reactions and irritable bowel syndrome. Alverine citrate may possess visceral antinociceptive properties in a rat model of rectal distension-induced abdominal contractions. This study was designed to evaluate the pharmacological properties of alverine citrate in a rat model of rectal hyperalgesia induced by 5-HTP (5-HT precursor) and by a selective 5-HT1A agonist (8-OH-DPAT) and to compare this activity with a reference 5-HT1A antagonist (WAY 100635). At 4 h after their administration, 5-HTP and 8-OH-DPAT increased the number of abdominal contractions in response to rectal distension at the lowest volume of distension (0.4 mL). When injected intraperitoneally before 8-OH-DPAT and 5-HTP, WAY 100635 (1 mg kg(-1)) blocked their nociceptive effect, but also reduced the response to the highest volume of distension (1.6 mL). Similarly, when injected intraperitoneally, alverine citrate (20 mg kg(-1)) suppressed the effect of 5-HTP, but not that of 8-OH-DPAT. However, when injected intracerebroventricularly (75 microg/rat) alverine citrate reduced 8-OH-DPAT-induced enhancement of rectal distension-induced abdominal contractions. In-vitro binding studies revealed that alverine citrate had a high affinity for 5-HT1A receptors and a weak affinity for 5-HT3 and 5-HT4 subtypes. These results suggest that 5-HTP-induced rectal hypersensitivity involves 5-TH1A receptors and that alverine citrate acts as a selective antagonist at the 5-HT1A receptor subtype to block both 5-HTP and 8-OH-DPAT-induced rectal hypersensitivity. PMID:11697552

  20. μ-Opioid and 5-HT1A receptors heterodimerize and show signalling crosstalk via G protein and MAP-kinase pathways.

    PubMed

    Cussac, Didier; Rauly-Lestienne, Isabelle; Heusler, Peter; Finana, Frédéric; Cathala, Claudie; Bernois, Sophie; De Vries, Luc

    2012-08-01

    μ-opioid receptors have been shown to form heterodimers with several G protein coupled receptors involved in pain regulation such as α(2A)-adrenergic and neurokinin 1 receptors. Because the 5-HT(1A) receptor is also involved in pain control, we investigated whether it can interact with the μ-opioid receptor in cell lines. Using epitope-tagged μ-opioid and 5-HT(1A) receptors, we show that both receptors can co-immunoprecipate when expressed in the same cells. This physical interaction was corroborated by a Bioluminescence Resonance Energy Transfer signal between the μ-opioid receptor fused to Renilla luciferase and the 5-HT(1A) receptor fused to the Green Fluorescent Protein. Consistent with the presence of functional heterodimers, the μ-opioid receptor activated a Gα(o) protein covalently fused to the 5-HT(1A) receptor in membrane preparations as well as a Gα(15) protein fused to the 5-HT(1A) receptor in living cells. We demonstrate that both receptors can coexerce control of the ERK1/2 pathway: for example, μ-opioid receptor-induced ERK1/2 phosphorylation was selectively desensitized by 5-HT(1A) receptor activation. Although 5-HT(1A) and μ-opioid receptors were capable to internalize in response to their own activation, they were ineffective to induce the co-internalization of their partners. Thus, we show a functional heterodimerization of μ-opioid and 5-HT(1A) receptors in cell lines, a complex that might play a role in the control of pain in vivo. These results also support the potential therapeutic action of 5-HT(1A) agonists against nociceptive processes.

  1. Serotonin, serotonin 5-HT(1A) receptors and dopamine in blood peripheral lymphocytes of major depression patients.

    PubMed

    Fajardo, O; Galeno, J; Urbina, M; Carreira, I; Lima, L

    2003-09-01

    There are increasing evidences of cell markers present in the immune and the nervous systems. These include neurotransmitter receptors and transporters. Serotonin receptor subtypes are related to depression and also have been shown to be present in certain cells of the immune system. In the present report, we determined the presence of 5-HT(1A) receptors by the binding of the selective agonist 8-hydroxy-2-(di-n-propyl-amino)tetralin in lymphocytes of peripheral blood isolated by Ficoll/Hypaque gradients from controls and depressed patients. The capacity of these receptors was around 24 fmol/10(6) cells in both groups of subjects, without significant difference among them. The affinity was in the nM range and either differ between controls and patients. Serotonin, 5-hydroxyindoleacetic acid, dopamine and 3,4-dihydroxyphenylacetic acid were determined by HPLC with electrochemical detector. There were no significant differences between controls and major depression patients in the values obtained for rich and poor platelet plasma or in the isolated cells. However, there was a reduction in serotonin turnover rate indicated by an increase in the ratio serotonin/5-hydroxyindoleacetic acid, but not in that of dopamine, in lymphocytes of major depression patients. Thus, there is a serotonergic dysfunction in immune circulating cells of major depression patients, without changes in the number of 5-HT(1A) receptors, although the coupling of these receptors to transduction mechanisms could be affected and may be related to the alteration of 5-HT turnover rate.

  2. 5-HT(1A) receptors transactivate the platelet-derived growth factor receptor type beta in neuronal cells.

    PubMed

    Kruk, Jeff S; Vasefi, Maryam S; Liu, Hui; Heikkila, John J; Beazely, Michael A

    2013-01-01

    In the absence of ligand, certain growth factor receptors can be activated via G-protein coupled receptor (GPCR) activation in a process termed transactivation. Serotonin (5-HT) receptors can transactivate platelet-derived growth factor (PDGF) β receptors in smooth muscle cells, but it is not known if similar pathways occur in neuronal cells. Here we show that 5-HT can transiently increase the phosphorylation of PDGFβ receptors through 5-HT(1A) receptors in a time- and dose-dependent manner in SH-SY5Y neuroblastoma cells. 5-HT also transactivates PDGFβ receptors in primary cortical neurons. This transactivation pathway is pertussis-toxin sensitive and Src tyrosine kinase-dependent. This pathway is also dependent on phospholipase C activity and intracellular calcium signaling. Several studies involving PDGFβ receptor transactivation by GPCRs have also demonstrated a PDGFβ receptor-dependent increase in the phosphorylation of ERK1/2. Yet in SH-SY5Y cells, 5-HT treatment causes a PDGFβ receptor-independent increase in ERK1/2 phosphorylation. This crosstalk between 5-HT and PDGFβ receptors identifies a potentially important signaling link between the serotonergic system and growth factor signaling in neurons. PMID:23006663

  3. Motor effects of the non-psychotropic phytocannabinoid cannabidiol that are mediated by 5-HT1A receptors.

    PubMed

    Espejo-Porras, Francisco; Fernández-Ruiz, Javier; Pertwee, Roger G; Mechoulam, Raphael; García, Concepción

    2013-12-01

    The broad presence of CB1 receptors in the basal ganglia, mainly in GABA- or glutamate-containing neurons, as well as the presence of TRPV1 receptors in dopaminergic neurons and the identification of CB2 receptors in some neuronal subpopulations within the basal ganglia, explain the powerful motor effects exerted by those cannabinoids that can activate/block these receptors. By contrast, cannabidiol (CBD), a phytocannabinoid with a broad therapeutic profile, is generally presented as an example of a cannabinoid compound with no motor effects due to its poor affinity for the CB1 and the CB2 receptor, despite its activity at the TRPV1 receptor. However, recent evidence suggests that CBD may interact with the serotonin 5-HT1A receptor to produce some of its beneficial effects. This may enable CBD to directly influence motor activity through the well-demonstrated role of serotonergic transmission in the basal ganglia. We have investigated this issue in rats using three different pharmacological and neurochemical approaches. First, we compared the motor effects of various i.p. doses of CBD with the selective 5-HT1A receptor agonist, 8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT; i.p.). Second, we investigated whether the motor effects of CBD are sensitive to 5-HT1A receptor blockade in comparison with CB1 receptor antagonism. Finally, we investigated whether CBD was able to potentiate the effect of a sub-effective dose of 8-OH-DPAT. Our results demonstrated that: (i) only high doses of CBD (>10 mg/kg) altered motor behavior measured in a computer-aided actimeter; (ii) these alterations were restricted to vertical activity (rearing) with only modest changes in other parameters; (iii) similar effects were produced by 8-OH-DPAT (1 mg/kg), although this agonist affected exclusively vertical activity, with no effects on other motor parameters, and it showed always more potency than CBD; (iv) the effects of 8-OH-DPAT (1 mg/kg) and CBD (20 mg/kg) on vertical activity

  4. The effect of 5-HT1A receptor agonists on locomotor activity in the guinea-pig.

    PubMed Central

    Evenden, J. L.

    1994-01-01

    1. The present study examined the effects of 8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT), flesinoxan, ipsapirone and buspirone, all agonists at the 5-HT1A receptor, on the locomotor activity of guinea-pigs. The effects of these drugs were contrasted with those of the non-selective 5-HT agonist, 5-methoxy-N,N-dimethyl tryptamine (5-MeO-DMT) and the dopamine D2 antagonist, raclopride. 2. 8-OH-DPAT, flesinoxan and 5-MeO-DMT markedly increased the locomotor activity of naive, unhabituated guinea-pigs in a dose-dependent manner. Buspirone also did so, although to a lesser extent and for a shorter time. The doses at which this effect was seen were higher than those normally employed in rats. Ipsapirone and raclopride had no significant effects on locomotor activity. 3. The locomotor activity increasing effect of 1.0 mg kg-1 8-OH-DPAT was blocked by the selective 5-HT1A antagonist (S)-UH-301 (3.0 and 10.0 mg kg-1), but not by (-)-alprenolol (15.0 mg kg-1). Ipsapirone (30.0 mg kg-1) and raclopride (3.0 mg kg-1) antagonized 8-OH-DPAT-induced locomotor activity but only to a small extent. The 5-HT reuptake inhibitor, zimelidine (10.0 mg kg-1) had no effect. 4. The effect of the 5-HT1A agonists in the guinea-pig contrasts with the effects of 8-OH-DPAT on the locomotor activity of unhabituated rats and mice tested in the same apparatus, but are similar to the effects of 8-OH-DPAT on habituated rats, which show a low baseline of activity.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7921613

  5. Serotonin 1A receptor (5-HT1A) of the sea lamprey: cDNA cloning and expression in the central nervous system.

    PubMed

    Cornide-Petronio, María Eugenia; Anadón, Ramón; Barreiro-Iglesias, Antón; Rodicio, María Celina

    2013-09-01

    Serotonergic cells are among the earliest neurons to be born in the developing central nervous system and serotonin is known to regulate the development of the nervous system. One of the major targets of the activity of serotonergic cells is the serotonin 1A receptor (5-HT1A), an ancestral archetypical serotonin receptor. In this study, we cloned and characterized the 3D structure of the sea lamprey 5-HT1A, and studied the expression of its transcript in the central nervous system by means of in situ hybridization. In phylogenetic analyses, the sea lamprey 5-HT1A sequence clustered together with 5-HT1A sequences of vertebrates and emerged as an outgroup to all gnathostome sequences. In situ hybridization analysis during prolarval, larval and adult stages showed a widespread expression of the lamprey 5-ht1a transcript. In P1 prolarvae 5-ht1a mRNA expression was observed in diencephalic nuclei, the rhombencephalon and rostral spinal cord. At P2 prolarval stage the 5-ht1a expression extended to other brain areas including telencephalic regions. 5-ht1a expression in larvae was observed throughout almost all the main brain regions with the strongest expression in the olfactory bulbs, lateral pallium, striatum, preoptic region, habenula, prethalamus, thalamus, pretectum, hypothalamus, rhombencephalic reticular area, dorsal column nucleus and rostral spinal cord. In adults, the 5-ht1a transcript was also observed in cells of the subcommissural organ. Comparison of the expression of 5-ht1a between the sea lamprey and other vertebrates reveals a conserved pattern in most of the brain regions, likely reflecting the ancestral vertebrate condition.

  6. Serotonin 1A receptor (5-HT1A) of the sea lamprey: cDNA cloning and expression in the central nervous system.

    PubMed

    Cornide-Petronio, María Eugenia; Anadón, Ramón; Barreiro-Iglesias, Antón; Rodicio, María Celina

    2013-09-01

    Serotonergic cells are among the earliest neurons to be born in the developing central nervous system and serotonin is known to regulate the development of the nervous system. One of the major targets of the activity of serotonergic cells is the serotonin 1A receptor (5-HT1A), an ancestral archetypical serotonin receptor. In this study, we cloned and characterized the 3D structure of the sea lamprey 5-HT1A, and studied the expression of its transcript in the central nervous system by means of in situ hybridization. In phylogenetic analyses, the sea lamprey 5-HT1A sequence clustered together with 5-HT1A sequences of vertebrates and emerged as an outgroup to all gnathostome sequences. In situ hybridization analysis during prolarval, larval and adult stages showed a widespread expression of the lamprey 5-ht1a transcript. In P1 prolarvae 5-ht1a mRNA expression was observed in diencephalic nuclei, the rhombencephalon and rostral spinal cord. At P2 prolarval stage the 5-ht1a expression extended to other brain areas including telencephalic regions. 5-ht1a expression in larvae was observed throughout almost all the main brain regions with the strongest expression in the olfactory bulbs, lateral pallium, striatum, preoptic region, habenula, prethalamus, thalamus, pretectum, hypothalamus, rhombencephalic reticular area, dorsal column nucleus and rostral spinal cord. In adults, the 5-ht1a transcript was also observed in cells of the subcommissural organ. Comparison of the expression of 5-ht1a between the sea lamprey and other vertebrates reveals a conserved pattern in most of the brain regions, likely reflecting the ancestral vertebrate condition. PMID:23052550

  7. Enhancement of agonist binding to 5-HT1A receptors in rat brain membranes by millimolar Mn2+.

    PubMed

    Parkel, Sven; Näsman, Johnny; Rinken, Ago

    2009-06-19

    Manganese in millimolar concentration caused increase in specific binding of [(3)H]8-OH-DPAT to rat hippocampal membranes up to 44% in comparison with experiments in the presence of Mg(2+), while no significant differences were found in rat cortical membranes. Similar increase in high-affinity agonist binding sites by Mn(2+) was found in displacement curves of 8-OH-DPAT, where antagonist [(3)H]WAY100635 was used as reporter ligand. The removal of bivalent ions with EDTA caused full loss of high-affinity binding of agonists, but not for antagonists. Therefore it was hypothesized, that the effect of Mn(2+)- and Mg(2+)-ions was modulated through their action on different G-proteins. Results showed that efficient coupling of G-protein and 5-HT(1A) receptors is crucial to modify Mg(2+) and Mn(2+) effects, whereas Mn(2+) is more potent stabilizer of agonist high-affinity binding, especially when GTPgammaS is present. Using Sf9 cells as model system, we have shown that G(i1) proteins are required to modulate Mn(2+)-dependent high-affinity agonist binding to 5-HT(1A) receptors, but further studies are necessary to find the cofactors of Mn(2+) modulation to signal transduction.

  8. Pharmacological characterization of LY293284: A 5-HT1A receptor agonist with high potency and selectivity.

    PubMed

    Foreman, M M; Fuller, R W; Rasmussen, K; Nelson, D L; Calligaro, D O; Zhang, L; Barrett, J E; Booher, R N; Paget, C J; Flaugh, M E

    1994-09-01

    (-)-LY293284, (-)-4R-6-acetyl-4-(di-n-propylamino)1,3,4,5- tetrahydrobenz[c,d]indole, is a conformationally restricted tryptamine derivative with an acetyl group serving as a protophilic substitution for the hydroxyl in serotonin (5-HT). In ligand displacement studies, LY293284 had a Ki of 0.07 nM for the 5-HT1A receptor but no affinity for other monoaminergic receptors within 3 orders of magnitude. LY293284 was evaluated in in vivo models, which have been used as markers for presynaptic and postsynaptic 5-HT1A receptor activity. LY293284 decreased hypothalamic 5-hydroxyindoleacetic acid levels (ED50, 2.9 micrograms/kg s.c.) and dorsal raphe serotonergic neuron firing rate (ED50, 0.08 micrograms/kg s.c.), which are accepted indices of presynaptic activity. LY293284 also induced a reduction in body temperature in rats (ED50, 3.6 micrograms/kg s.c.), which was blocked by pretreatment with (+/-)-pindolol. Hypothermic responses of rats to 5-HT1A agonists have had both pre- and postsynaptic characteristics in previous studies. The ED50 values for 8-hydroxy-2-(di-n-propylamino)-tetralin (8-OH-DPAT) in these tests were 15 to 45 times higher than those observed for LY293284. In models for postsynaptic activity, the ED50 for LY293284 for elevating serum corticosterone levels was 9.7 micrograms/kg s.c. and the minimum effective doses to induce lower lip retraction and flat posture were 3 micrograms/kg s.c. For comparison, the same indices obtained for 8-OH-DPAT were 222.4 and 100 micrograms/kg, respectively. The 5-HT syndrome responses induced by LY293284 were also attenuated by pretreatment with (+/-)-pindolol. LY293284 was 10 times more potent than 8-OH-DPAT in a drug discrimination test that used pigeons trained to identify 8-OH-DPAT. In sexual behavior tests with male rats, LY293284 induced a maximal reduction in ejaculatory latency at 0.01 micrograms/kg s.c., which was approximately 10 times higher potency than 8-OH-DPAT. In the pigeon conflict model for anxiolytic

  9. Cannabidiol attenuates catalepsy induced by distinct pharmacological mechanisms via 5-HT1A receptor activation in mice.

    PubMed

    Gomes, Felipe V; Del Bel, Elaine A; Guimarães, Francisco S

    2013-10-01

    Cannabidiol (CBD) is a non-psychotomimetic compound from Cannabis sativa plant that produces antipsychotic effects in rodents and humans. It also reverses L-dopa-induced psychotic symptoms and improves motor function in Parkinson's patients. This latter effect raised the possibility that CBD could have beneficial effects on motor related striatal disorders. To investigate this possibility we evaluated if CBD would prevent catalepsy induced by drugs with distinct pharmacological mechanisms. The catalepsy test is largely used to investigate impairments of motor function caused by interference on striatal function. Male Swiss mice received acute pretreatment with CBD (5, 15, 30 or 60mg/kg, ip) 30min prior to the D2 receptor antagonist haloperidol (0.6mg/kg), the non-selective nitric oxide synthase (NOS) inhibitor L-nitro-N-arginine (L-NOARG, 80mg/kg) or the CB1 receptor agonist WIN55,212-2 (5mg/kg). The mice were tested 1, 2 or 4h after haloperidol, L-NOARG or WIN55,212-2 injection. These drugs significantly increased catalepsy time and this effect was attenuated dose-dependently by CBD. CBD, by itself, did not induce catalepsy. In a second set of experiments the mechanism of CBD effects was investigated. Thirty minutes before CBD (30mg/kg) the animals received the 5-HT1A receptor antagonist WAY100635 (0.1mg/kg). The anticataleptic effect of CBD was prevented by WAY100635. These findings indicate that CBD can attenuate catalepsy caused by different mechanisms (D2 blockade, NOS inhibition and CB1 agonism) via 5-HT1A receptor activation, suggesting that it could be useful in the treatment of striatal disorders.

  10. Adrenalectomy modifies the hippocampal 5-HT(1A) receptors and the anxiolytic-like effect of 8-OH-DPAT in rats.

    PubMed

    Briones-Aranda, Alfredo; Castillo-Salazar, Mariano; Picazo, Ofir

    2009-03-01

    Stress is closely related with levels of corticosteroid and corticotrophin releasing factor, which at the same time can modify 5-HT(1A) receptors and brain serotonin levels. Consequently, the absence of corticosteroids in rats induced by an adrenalectomy could be useful to understand the functionality of the brain serotonergic system after a stressing event. The influence of 15 min of forced swimming was explored on sham and adrenalectomized rats by measuring the 5-HT(1A) receptor density in raphe and hippocampus. Other previously stressed groups (sham and adrenalectomized) were tested in two anxiety models with the 5-HT(1A) agonist 8-OH-DPAT, the postsynaptic antagonist MM-77, and with a combination of these two compounds. It was found that the removal of adrenals in rats that were not previously stressed induced an increase in the postsynaptic 5-HT(1A) receptor density. On the other hand, an adrenalectomy in rats that were previously stressed induced a reduction in the same receptor density. Adrenal gland removal induced an anxiolytic-like effect. However, after the injection of 8-OH-DPAT, adrenalectomized rats showed anxiogenic-like actions, an effect which was reversed by MM-77. Data show that changes in 5-HT(1A) receptors density caused by a stressful session can have behavioral consequences, thus emphasizing the need to reconsider the clinical use of 5-HT(1A) ligands after traumatic events.

  11. CREB-mediated synaptogenesis and neurogenesis is crucial for the role of 5-HT1a receptors in modulating anxiety behaviors.

    PubMed

    Zhang, Jing; Cai, Cheng-Yun; Wu, Hai-Yin; Zhu, Li-Juan; Luo, Chun-Xia; Zhu, Dong-Ya

    2016-01-01

    Serotonin 1a-receptor (5-HT1aR) has been specifically implicated in the pathogenesis of anxiety. However, the mechanism underlying the role of 5-HT1aR in anxiety remains poorly understood. Here we show in mice that the transcription factor cAMP response element binding protein (CREB) in the hippocampus functions as an effector of 5-HT1aR in modulating anxiety-related behaviors. We generated recombinant lentivirus LV-CREB133-GFP expressing a dominant negative CREB which could not be phosphorylated at Ser133 to specifically reduce CREB activity, and LV-VP16-CREB-GFP expressing a constitutively active fusion protein VP16-CREB which could be phosphorylated by itself to specifically enhance CREB activity. LV-CREB133-GFP neutralized 5-HT1aR agonist-induced up-regulation of synapse density, spine density, dendrite complexity, neurogenesis, and the expression of synapsin and spinophilin, two well-characterized synaptic proteins, and abolished the anxiolytic effect of 5-HT1aR agonist; whereas LV-VP16-CREB-GFP rescued the 5-HT1aR antagonist-induced down-regulation of synapse density, spine density, dendrite complexity, neurogenesis and synapsin and spinophilin expression, and reversed the anxiogenic effect of 5-HT1aR antagonist. The deletion of neurogenesis by irradiation or the diminution of synaptogenesis by knockdown of synapsin expression abolished the anxiolytic effects of both CREB and 5-HT1aR activation. These findings suggest that CREB-mediated hippoacampus structural plasticity is crucial for the role of 5-HT1aR in modulating anxiety-related behaviors. PMID:27404655

  12. CREB-mediated synaptogenesis and neurogenesis is crucial for the role of 5-HT1a receptors in modulating anxiety behaviors

    PubMed Central

    Zhang, Jing; Cai, Cheng-Yun; Wu, Hai-Yin; Zhu, Li-Juan; Luo, Chun-Xia; Zhu, Dong-Ya

    2016-01-01

    Serotonin 1a-receptor (5-HT1aR) has been specifically implicated in the pathogenesis of anxiety. However, the mechanism underlying the role of 5-HT1aR in anxiety remains poorly understood. Here we show in mice that the transcription factor cAMP response element binding protein (CREB) in the hippocampus functions as an effector of 5-HT1aR in modulating anxiety-related behaviors. We generated recombinant lentivirus LV-CREB133-GFP expressing a dominant negative CREB which could not be phosphorylated at Ser133 to specifically reduce CREB activity, and LV-VP16-CREB-GFP expressing a constitutively active fusion protein VP16-CREB which could be phosphorylated by itself to specifically enhance CREB activity. LV-CREB133-GFP neutralized 5-HT1aR agonist-induced up-regulation of synapse density, spine density, dendrite complexity, neurogenesis, and the expression of synapsin and spinophilin, two well-characterized synaptic proteins, and abolished the anxiolytic effect of 5-HT1aR agonist; whereas LV-VP16-CREB-GFP rescued the 5-HT1aR antagonist-induced down-regulation of synapse density, spine density, dendrite complexity, neurogenesis and synapsin and spinophilin expression, and reversed the anxiogenic effect of 5-HT1aR antagonist. The deletion of neurogenesis by irradiation or the diminution of synaptogenesis by knockdown of synapsin expression abolished the anxiolytic effects of both CREB and 5-HT1aR activation. These findings suggest that CREB-mediated hippoacampus structural plasticity is crucial for the role of 5-HT1aR in modulating anxiety-related behaviors. PMID:27404655

  13. Central PGE2 exhibits anxiolytic-like activity via EP1 and EP4 receptors in a manner dependent on serotonin 5-HT1A, dopamine D1 and GABAA receptors.

    PubMed

    Suzuki, Chihiro; Miyamoto, Chihiro; Furuyashiki, Tomoyuki; Narumiya, Shuh; Ohinata, Kousaku

    2011-07-21

    We found that centrally administered prostaglandin (PG) E(2) exhibited anxiolytic-like activity in the elevated plus-maze and open field test in mice. Agonists selective for EP(1) and EP(4) receptors, among four receptor subtypes for PGE(2), mimicked the anxiolytic-like activity of PGE(2). The anxiolytic-like activity of PGE(2) was blocked by an EP(1) or EP(4) antagonist, as well as in EP(4) but not EP(1) knockout mice. Central activation of either EP(1) or EP(4) receptors resulted in anxiolytic-like activity. The PGE(2)-induced anxiolytic-like activity was inhibited by antagonists for serotonin 5-HT(1A), dopamine D(1) and GABA(A) receptors. Taken together, PGE(2) exhibits anxiolytic-like activity via EP(1) and EP(4) receptors, with downstream involvement of 5-HT(1A), D(1) and GABA(A) receptor systems.

  14. Divergent effects of the ‘biased’ 5-HT1A receptor agonists F15599 and F13714 in a novel object pattern separation task

    PubMed Central

    van Goethem, N P; Schreiber, R; Newman-Tancredi, A; Varney, M; Prickaerts, J

    2015-01-01

    Background and Purpose Pattern separation, that is, the formation of distinct representations from similar inputs, is an important hippocampal process implicated in cognitive domains like episodic memory. A deficit in pattern separation could lead to memory impairments in several psychiatric and neurological disorders. Hence, mechanisms by which pattern separation can be increased are of potential therapeutic interest. Experimental approach 5-HT1A receptors are involved in spatial memory. Herein we tested the ‘biased’ 5-HT1A receptor agonists F15599, which preferentially activates post-synaptic heteroreceptors, and F13714, which preferentially activates raphe-located autoreceptors, in rats in a novel spatial task assessing pattern separation, the object pattern separation (OPS) task. Key Results The acetylcholinesterase inhibitor donepezil, which served as a positive control, significantly improved spatial pattern separation at a dose of 1 mg·kg−1, p.o. F15599 increased pattern separation at 0.04 mg·kg−1, i.p., while F13714 decreased pattern separation at 0.0025 mg·kg−1, i.p. The selective 5-HT1A receptor antagonist WAY-100635 (0.63 mg·kg−1, s.c.) counteracted the effects of both agonists. These data suggest that acute preferential activation of post-synaptic 5-HT1A heteroreceptors improves spatial pattern separation, whereas acute preferential activation of raphe-located 5-HT1A autoreceptors impairs performance. Conclusions and Implications We successfully established and validated a novel, simple and robust OPS task and observed a diverging profile of response with ‘biased’ 5-HT1A receptor agonists based on their targeting of receptors in distinct brain regions. Our data suggest that the post-synaptic 5-HT1A receptor consists of a potential novel molecular target to improve pattern separation performance. PMID:25572672

  15. Differential effects of amyloid-beta 1-40 and 1-42 fibrils on 5-HT1A serotonin receptors in rat brain.

    PubMed

    Verdurand, Mathieu; Chauveau, Fabien; Daoust, Alexia; Morel, Anne-Laure; Bonnefoi, Frédéric; Liger, François; Bérod, Anne; Zimmer, Luc

    2016-04-01

    Evidence accumulates suggesting a complex interplay between neurodegenerative processes and serotonergic neurotransmission. We have previously reported an overexpression of serotonin 5-HT1A receptors (5-HT(1A)R) after intrahippocampal injections of amyloid-beta 1-40 (Aβ40) fibrils in rats. This serotonergic reactivity paralleled results from clinical positron emission tomography studies with [(18)F]MPPF revealing an overexpression of 5-HT(1A)R in the hippocampus of patients with mild cognitive impairment. Because Aβ40 and Aβ42 isoforms are found in amyloid plaques, we tested in this study the hypothesis of a peptide- and region-specific 5-HT(1A)R reactivity by injecting them, separately, into the hippocampus or striatum of rats. [(18)F]MPPF in vitro autoradiography revealed that Aβ40 fibrils, but not Aβ42, were triggering an overexpression of 5-HT(1A)R in the hippocampus and striatum of rat brains after 7 days. Immunohistochemical approaches targeting neuronal precursor cells, mature neurons, and astrocytes showed that Aβ42 fibrils caused more pathophysiological damages than Aβ40 fibrils. The mechanisms of Aβ40 fibrils-induced 5-HT(1A)R expression remains unknown, but hypotheses including neurogenesis, glial expression, and axonal sprouting are discussed. PMID:26973100

  16. Evaluation of Serotonin 5-HT1A Receptors in Rodent Models using [18F]Mefway PET¶

    PubMed Central

    Saigal, Neil; Bajwa, Alisha K.; Faheem, Sara S.; Coleman, Robert A.; Pandey, Suresh K.; Constantinescu, Cristian C.; Fong, Vanessa; Mukherjee, Jogeshwar

    2013-01-01

    Introduction Serotonin 5-HT1A receptors have been investigated in various CNS disorders, including epilepsy, mood disorders and neurodegeneration. [18F]Mefway (N-{2-[4-(2'-methoxyphenyl)piperazinyl]ethyl}-N-(2-pyridyl)-N-(cis/trans-4'-[18F]fluoromethylcyclohexane)-carboxamide) has been developed as a suitable positron emission tomography (PET) imaging agent for these receptors. We have now evaluated the suitability of [18F]trans-mefway in rat and mouse models using PET and computerized tomography (CT) imaging and corroborated with ex vivo and in vitro autoradiographic studies. Methods Normal Sprague-Dawley rats and Balb/C mice were used for PET/CT imaging using intravenously injected [18F]trans-mefway. Brain PET data were coregistered with rat and mouse magnetic resonance (MR) imaging template and regional distribution of radioactivity was quantitated. Select animals were used for ex vivo autoradiographic studies in order to confirm regional brain distribution and quantitative measures of binding, using brain region to cerebellum ratios. Binding affinity of trans-mefway and WAY-100635 was measured in rat brain homogenates. Distribution of [18F]trans-4-fluoromethylcyclohexane carboxylate ([18F]FMCHA), a major metabolite of [18F] trans-mefway, was assessed in the rat by PET/CT. Results The inhibition constant, Ki for trans-mefway was 0.84 nM and that for WAY-100635 was 1.07 nM. Rapid brain uptake of [18F]trans-mefway was observed in all rat brain regions and clearance from cerebellum was fast and was used as a reference region in all studies. Distribution of [18F]trans-mefway in various brain regions was consistent in PET and in vitro studies. The dorsal raphe was visualized and quantified in the rat PET but identification in the mouse was difficult. The rank order of binding to the various brain regions was hippocampus>frontal cortex>anterior cingulate cortex>lateral septal nuclei>dorsal raphe nuclei. Conclusion [18F]trans-Mefway appears to be an effective 5-HT1A

  17. Potentiating effect of spinosin, a C-glycoside flavonoid of Semen Ziziphi spinosae, on pentobarbital-induced sleep may be related to postsynaptic 5-HT(1A) receptors.

    PubMed

    Wang, L-E; Cui, X-Y; Cui, S-Y; Cao, J-X; Zhang, J; Zhang, Y-H; Zhang, Q-Y; Bai, Y-J; Zhao, Y-Y

    2010-05-01

    Previous results have suggested that spinosin, a C-glycoside flavonoid of Semen Ziziphi spinosae, potentiates pentobarbital-induced sleep via the serotonergic system. The present study investigated whether spinosin potentiates pentobarbital-induced sleep via serotonin-1A (5-hydroxytryptamine, 5-HT(1A)) receptors. The results demonstrated that spinosin significantly augmented pentobarbital (35 mg/kg, i.p.)-induced sleep in rats, reflected by reduced sleep latency and increased total sleep time, non-rapid eye movement (NREM) sleep time, and REM sleep time. With regard to NREM sleep duration, spinosin mainly increased slow-wave sleep (SWS). Additionally, spinosin (15mg/kg, i.g.) significantly antagonized 5-HT(1A) agonist 8-OH-DPAT (0.1mg/kg, i.p.)-induced reductions in total sleep time, NREM sleep, REM sleep, and SWS in pentobarbital-treated rats. These results suggest that spinosin may be an antagonist at postsynaptic 5-HT(1A) receptors because these effects of 8-OH-DPAT were considered to be mediated via postsynaptic 5-HT(1A) receptors. Moreover, co-administration of spinosin and the 5-HT(1A) antagonist 4-iodo-N-{2-[4-(methoxyphenyl)-1-piperazinyl]ethyl}-N-2-pyridinylbenzamide (p-MPPI), at doses that are ineffective when administered alone (spinosin 5mg/kg, p-MPPI 1mg/kg), had significant augmentative effects on pentobarbital-induced sleep, reflected by reduced sleep latency and increased total sleep time, NREM sleep, and REM sleep. In contrast to the attenuating effects of p-MPPI on REM sleep via presynaptic 5-HT(1A) autoreceptors, 15mg/kg spinosin significantly increased REM sleep. These results suggest that the effect of spinosin on REM sleep in pentobarbital-treated rats may be related to postsynaptic 5-HT(1A) receptors. PMID:20171860

  18. Selective reduction by isolation rearing of 5-HT1A receptor-mediated dopamine release in vivo in the frontal cortex of mice.

    PubMed

    Ago, Y; Sakaue, M; Baba, A; Matsuda, T

    2002-10-01

    Serotonin (5-HT)1A receptors modulate in vivo release of brain monoaminergic neurotransmitters which may be involved in isolation-induced aggressive behavior. The present study examined the effect of isolation rearing on the 5-HT1A receptor-mediated modulation of dopamine (DA), 5-HT and noradrenaline (NA) release in the frontal cortex of mice. The selective 5-HT1A receptor agonist (S)-5-[-[(1,4-benzodioxan-2-ylmethyl)amino]propoxy]-1,3-benzodioxole HCl (MKC-242) increased the release of DA and NA and decreased the release of 5-HT in the frontal cortex of mice. The effect of MKC-242 on DA release was significantly less in isolation-reared mice than in group-reared mice, while effects of the drug on NA and 5-HT release did not differ between both groups. The effect of the other 5-HT1A receptor agonist 8-hydroxy-2-(di-n-propylamino)tetralin on cortical DA release was also less in isolation-reared mice than in group-reared mice, and that of the drug on cortical 5-HT release did not differ between both groups. In contrast to MKC-242-induced DA release, amphetamine-induced increase in cortical DA release in vivo was greater in isolation-reared mice. The present findings suggest that isolation rearing enhances the activity of cortical dopaminergic neurons and reduces selectively the 5-HT1A receptor-mediated release of DA in the cortex.

  19. Cartography of 5-HT1A and 5-HT2A Receptor Subtypes in Prefrontal Cortex and Its Projections.

    PubMed

    Mengod, Guadalupe; Palacios, José M; Cortés, Roser

    2015-07-15

    Since the development of chemical neuroanatomical tools in the 1960s, a tremendous wealth of information has been generated on the anatomical components of the serotonergic system, at the microscopic level in the brain including the prefrontal cortex (PFC). The PFC receives a widespread distribution of serotonin (5-hydroxytryptamine, 5-HT) terminals from the median and dorsal raphe nuclei. 5-HT receptors were first visualized using radioligand autoradiography in the late 1980s and early 1990s and showed, in contrast to 5-HT innervation, a differential distribution of binding sites associated with different 5-HT receptor subtypes. Due to the cloning of the different 5-HT receptor subtype genes in the late 1980s and early 1990s, it was possible, using in situ hybridization histochemistry, to localize cells expressing mRNA for these receptors. Double in situ hybridization histochemistry and immunohistochemistry allowed for the chemical characterization of the phenotype of cells expressing 5-HT receptors. Tract tracing technology allowed a detailed cartography of the neuronal connections of PFC and other brain areas. Based on these data, maps have been constructed that reflect our current understanding of the different circuits where 5-HT receptors can modulate the electrophysiological, pharmacological, and behavioral functions of the PFC. We will review current knowledge regarding the cellular localization of 5-HT1A and 5-HT2A receptors in mammalian PFC and their possible functions in the neuronal circuits of the PFC. We will discuss data generated in our laboratory as well as in others, focusing on localization in the pyramidal and GABAergic neuronal cell populations in different mammalian species using molecular neuroanatomy and on the connections with other brain regions. PMID:25739427

  20. Cartography of 5-HT1A and 5-HT2A Receptor Subtypes in Prefrontal Cortex and Its Projections.

    PubMed

    Mengod, Guadalupe; Palacios, José M; Cortés, Roser

    2015-07-15

    Since the development of chemical neuroanatomical tools in the 1960s, a tremendous wealth of information has been generated on the anatomical components of the serotonergic system, at the microscopic level in the brain including the prefrontal cortex (PFC). The PFC receives a widespread distribution of serotonin (5-hydroxytryptamine, 5-HT) terminals from the median and dorsal raphe nuclei. 5-HT receptors were first visualized using radioligand autoradiography in the late 1980s and early 1990s and showed, in contrast to 5-HT innervation, a differential distribution of binding sites associated with different 5-HT receptor subtypes. Due to the cloning of the different 5-HT receptor subtype genes in the late 1980s and early 1990s, it was possible, using in situ hybridization histochemistry, to localize cells expressing mRNA for these receptors. Double in situ hybridization histochemistry and immunohistochemistry allowed for the chemical characterization of the phenotype of cells expressing 5-HT receptors. Tract tracing technology allowed a detailed cartography of the neuronal connections of PFC and other brain areas. Based on these data, maps have been constructed that reflect our current understanding of the different circuits where 5-HT receptors can modulate the electrophysiological, pharmacological, and behavioral functions of the PFC. We will review current knowledge regarding the cellular localization of 5-HT1A and 5-HT2A receptors in mammalian PFC and their possible functions in the neuronal circuits of the PFC. We will discuss data generated in our laboratory as well as in others, focusing on localization in the pyramidal and GABAergic neuronal cell populations in different mammalian species using molecular neuroanatomy and on the connections with other brain regions.

  1. Effects of intra-prelimbic prefrontal cortex injection of cannabidiol on anxiety-like behavior: involvement of 5HT1A receptors and previous stressful experience.

    PubMed

    Fogaça, M V; Reis, F M C V; Campos, A C; Guimarães, F S

    2014-03-01

    The prelimbic medial prefrontal cortex (PL) is an important encephalic structure involved in the expression of emotional states. In a previous study, intra-PL injection of cannabidiol (CBD), a major non-psychotomimetic cannabinoid present in the Cannabis sativa plant, reduced the expression of fear conditioning response. Although its mechanism remains unclear, CBD can facilitate 5HT1A receptor-mediated neurotransmission when injected into several brain structures. This study was aimed at verifying if intra-PL CBD could also induce anxiolytic-like effect in a conceptually distinct animal model, the elevated plus maze (EPM). We also verified if CBD effects in the EPM and contextual fear conditioning test (CFC) depend on 5HT1A receptors and previous stressful experience. CBD induced opposite effects in the CFC and EPM, being anxiolytic and anxiogenic, respectively. Both responses were prevented by WAY100,635, a 5HT1A receptor antagonist. In animals that had been previously (24h) submitted to a stressful event (2h-restraint) CBD caused an anxiolytic, rather than anxiogenic, effect in the EPM. This anxiolytic response was abolished by previous injection of metyrapone, a glucocorticoid synthesis blocker. Moreover, restraint stress increased 5HT1A receptors expression in the dorsal raphe nucleus, an effect that was attenuated by injection of metyrapone before the restraint procedure. Taken together, these results suggest that CBD modulation of anxiety in the PL depend on 5HT1A-mediated neurotransmission and previous stressful experience.

  2. Alterations of 5-HT1A receptor-induced G-protein functional activation and relationship to memory deficits in patients with pharmacoresistant temporal lobe epilepsy.

    PubMed

    Cuellar-Herrera, Manola; Velasco, Ana Luisa; Velasco, Francisco; Trejo, David; Alonso-Vanegas, Mario; Nuche-Bricaire, Avril; Vázquez-Barrón, Daruni; Guevara-Guzmán, Rosalinda; Rocha, Luisa

    2014-12-01

    The 5-hydroxytryptamine-1A (5-HT1A) receptors are known to be involved in the inhibition of seizures in epilepsy. Moreover, studies propose a role for the 5-HT1A receptor in memory function; it is believed that the higher density of this receptor in the hippocampus plays an important role in its regulation. Positron emission tomography (PET) studies in patients with mesial temporal lobe epilepsy (mTLE) have demonstrated that a decrease in 5-HT1A receptor binding in temporal regions may play a role in memory impairment. The evidences lead us to speculate whether this decrease in receptor binding is associated with a reduced receptor number or if the functionality of the 5-HT1A receptor-induced G-protein activation and/or the second messenger cascade is modified. The purpose of the present study is to determine 5-HT1A receptor-induced G-protein functional activation by 8-OH-DPAT-stimulated [(35)S]GTPγS binding assay in hippocampal tissue of surgical patients with mTLE. We correlate functional activity with epilepsy history and neuropsychological assessment of memory. We found that maximum functional activation stimulation values (Emax) of [(35)S]GTPγS binding were significantly increased in mTLE group when compared to autopsy samples. Furthermore, significant correlations were found: (1) positive coefficients between the Emax with the age of patient and frequency of seizures; (2) negative coefficients between the Emax and working memory, immediate recall and delayed recall memory tasks. Our data suggest that the epileptic hippocampus of patients with mTLE presents an increase in 5-HT1A receptor-induced G-protein functional activation, and that this altered activity is related to age and seizure frequency, as well as to memory consolidation deficit.

  3. Alterations of 5-HT1A receptor-induced G-protein functional activation and relationship to memory deficits in patients with pharmacoresistant temporal lobe epilepsy.

    PubMed

    Cuellar-Herrera, Manola; Velasco, Ana Luisa; Velasco, Francisco; Trejo, David; Alonso-Vanegas, Mario; Nuche-Bricaire, Avril; Vázquez-Barrón, Daruni; Guevara-Guzmán, Rosalinda; Rocha, Luisa

    2014-12-01

    The 5-hydroxytryptamine-1A (5-HT1A) receptors are known to be involved in the inhibition of seizures in epilepsy. Moreover, studies propose a role for the 5-HT1A receptor in memory function; it is believed that the higher density of this receptor in the hippocampus plays an important role in its regulation. Positron emission tomography (PET) studies in patients with mesial temporal lobe epilepsy (mTLE) have demonstrated that a decrease in 5-HT1A receptor binding in temporal regions may play a role in memory impairment. The evidences lead us to speculate whether this decrease in receptor binding is associated with a reduced receptor number or if the functionality of the 5-HT1A receptor-induced G-protein activation and/or the second messenger cascade is modified. The purpose of the present study is to determine 5-HT1A receptor-induced G-protein functional activation by 8-OH-DPAT-stimulated [(35)S]GTPγS binding assay in hippocampal tissue of surgical patients with mTLE. We correlate functional activity with epilepsy history and neuropsychological assessment of memory. We found that maximum functional activation stimulation values (Emax) of [(35)S]GTPγS binding were significantly increased in mTLE group when compared to autopsy samples. Furthermore, significant correlations were found: (1) positive coefficients between the Emax with the age of patient and frequency of seizures; (2) negative coefficients between the Emax and working memory, immediate recall and delayed recall memory tasks. Our data suggest that the epileptic hippocampus of patients with mTLE presents an increase in 5-HT1A receptor-induced G-protein functional activation, and that this altered activity is related to age and seizure frequency, as well as to memory consolidation deficit. PMID:25304920

  4. Comparative assessment of (18) F-Mefway as a serotonin 5-HT1A receptor PET imaging agent across species: Rodents, nonhuman primates, and humans.

    PubMed

    Mukherjee, Jogeshwar; Bajwa, Alisha K; Wooten, Dustin W; Hillmer, Ansel T; Pan, Min-Liang; Pandey, Suresh K; Saigal, Neil; Christian, Bradley T

    2016-05-01

    We have developed (18) F-trans-Mefway ((18) F-Mefway) for positron emission tomography (PET) imaging studies of serotonin 5-HT1A receptors which are implicated in various brain functions. Translation of imaging the 5-HT1A receptor in animal models to humans will facilitate an understanding of the role of the receptor in human brain disorders. We report comparative brain distribution of (18) F-Mefway in normal mice, rats, monkeys, and healthy human volunteers. Mefway was found to be very selective, with subnanomolar affinity for the 5-HT1A receptor. Affinities of >55 nM were found for all other human-cloned receptor subtypes tested. Mefway was found to be a poor substrate (>30 μM) for the multidrug resistance 1 protein, suggesting low likelihood of brain uptake being affected by P-glycoprotein. Cerebellum was used as a reference region in all imaging studies across all species due to the low levels of (18) F-Mefway binding. Consistent binding of (18) F-Mefway in cortical regions, hippocampus, and raphe was observed across all species. (18) F-Mefway in the human brain regions correlated with the known postmortem distribution of 5-HT1A receptors. Quantitation of raphe was affected by the resolution of the PET scanners in rodents, whereas monkeys and humans showed a raphe to cerebellum ratio of approximately 3. (18) F-Mefway appears to be an effective 5-HT1A receptor imaging agent in all models, including humans. (18) F-Mefway therefore may be used to quantify 5-HT1A receptor distribution in brain regions for the study of various CNS disorders. J. Comp. Neurol. 524:1457-1471, 2016. © 2015 Wiley Periodicals, Inc.

  5. Oestradiol alters central 5HT1A receptor binding potential differences related to psychosocial stress but not differences related to 5HTTLPR genotype in female rhesus monkeys

    PubMed Central

    Michopoulos, Vasiliki; Diaz, Maylen Perez; Embree, Molly; Reding, Kathy; Votaw, John R.; Mun, Jiyoung; Voll, Ronald J.; Goodman, Mark M.; Wilson, Mark; Sanchez, Mar; Toufexis, Donna

    2014-01-01

    Social subordination in female macaques represents a well-described model of chronic psychosocial stress. Additionally, a length polymorphism (5HTTLPR) in the regulatory region of the serotonin (5HT) transporter (5HTT) gene (SLC6A4) is present in rhesus macaques, which has been linked to adverse outcomes similar to what has been described in humans with an analogous 5HTTLPR polymorphism. The present study determined the effects of social status and the 5HTTLPR genotype on 5HT1A receptor binding potential (5HT1A BPND) in brain regions implicated in emotional regulation and stress reactivity in ovariectomised female monkeys, and then assessed how these effects were altered by 17β-oestradiol (E2) treatment. Areas analyzed included the prefrontal cortex [anterior cingulate (ACC); medial prefrontal cortex (mPFC); dorsolateral prefrontal cortex; orbitofrontal prefrontal cortex], amygdala, hippocampus, hypothalamus and raphe nucleui. Positron emission tomography (PET) using p-[18F]MPPF was performed to determine the levels of 5HT1A BPND under a non-E2 and a 3-wk E2 treatment condition. The short variant (s-variant) 5HTTLPR genotype produced a significant reduction in 5HT1A BPND in the mPFC regardless of social status, and subordinate s-variant females showed a reduction in 5HT1A BPND within the ACC. Both these effects of 5HTTLPR were unaffected by E2. Additionally, E2 reduced 5HT1A BPND in the dorsal raphe of all females irrespective of psychosocial stress or 5HTTLPR genotype. Hippocampal 5HT1A BPND was attenuated in subordinate females regardless of 5HTTLPR genotype during the non-E2 condition, an effect that was normalised with E2. Similarly, 5HT1A BPND in the hypothalamus was significantly lower in subordinate females regardless of 5HTTLPR genotype, an effect reversed with E2. Together, the data indicate that the effect of E2 on modulation of central 5HT1A BPND may only occur in brain regions that show no 5HTTLPR genotype-linked control of 5HT1A binding. PMID:24382202

  6. TREK1 channel blockade induces an antidepressant-like response synergizing with 5-HT1A receptor signaling.

    PubMed

    Ye, Dongqing; Li, Yang; Zhang, Xiangrong; Guo, Fei; Geng, Leiyu; Zhang, Qi; Zhang, Zhijun

    2015-12-01

    Current antidepressants often remain the inadequate efficacy for many depressive patients, which warrant the necessary endeavor to develop the new molecules and targets for treating depression. Recently, the two-pore domain potassium channel TREK1 has been implicated in mood regulation and TREK-1 antagonists could be the promising antidepressant. This study has screened a TREK1 blocker (SID1900) with a satisfactory blood-brain barrier permeation and bioavailability. Electrophysiological research has shown that SID1900 and the previously reported TREK1 blocker (spadin) efficiently blocked TREK-1 current in HEK293 cells and specifically blocked two-pore domain potassium channels in primary-cultured rat hippocampal neurons. SID1900 and spadin induced a significant antidepressant-like response in the rat model of chronic unpredictable mild stress (CUMS). Both two TREK1 blockers substantially increased the firing rate of 5-HT-ergic neurons in the dorsal raphe nuclei (DRN) and PFC of CUMS rats. SID1900 and spadin significantly up-regulated the expression of PKA-pCREB-BDNF signaling in DRN, hippocampus and PFC of CUMS rats, which were enhanced and reversed by a 5-HTR1A agonist (8-OH-DPAT) and antagonist (WAY100635) respectively. The present findings suggested that TREK1 channel blockers posses the substantial antidepressant-like effect and have the potential synergistic effect with 5-HT1A receptor activation through the common CREB-BDNF signal transduction. PMID:26441141

  7. Effect of early rearing conditions on alcohol drinking and 5-HT1A receptor function in C57BL/6J mice.

    PubMed

    Advani, Tushar; Hensler, Julie G; Koek, Wouter

    2007-10-01

    We have evaluated in C57BL/6J mice the effect of maternal separation and post-weaning social isolation on ethanol intake, and on serotonin1A (5-HT1A) receptor function at the level of receptor-G protein interaction in the hippocampus and dorsal raphe nucleus. From postnatal days 2-14, litters were separated from the mother for 15 min (Handled) or for 180 min (Maternal separation). After weaning, pups were housed in pairs or in social isolation. At 2 months of age, ethanol intake and preference in mice were assessed using the two-bottle choice paradigm. Maternal separation increased ethanol preference in female mice that were subsequently housed in isolation. By contrast, post-weaning isolation increased ethanol preference and consumption in male mice regardless of pre-weaning rearing conditions. The increased ethanol preference and intake were limited to a 5% (v/v) concentration of ethanol. Our data suggest that adolescent mice are susceptible to the effects of post-weaning social isolation as shown by increased ethanol preference and consumption. Using quantitative autoradiography, 5-HT1A receptor number and function were determined by the binding of [3H]WAY-100635, and by [35S]GTPgammaS binding stimulated by the 5-HT1A receptor agonist 8-OH-DPAT, respectively. The binding experiments were done at approximately 3 months after the end of the two-bottle choice test in an attempt to minimize direct effects of ethanol drinking on 5-HT1A receptor function and number. 5-HT1A receptor-stimulated [35S]GTPgammaS binding in the dorsal raphe nucleus was increased in animals reared after weaning in isolation vs. in pairs, regardless of gender or pre-weaning rearing conditions. Our data suggest that there are long-term neurochemical consequences of social isolation of adolescent mice, specifically increased 5-HT1A receptor function in the dorsal raphe nucleus.

  8. Chronic mild stress and antidepressant treatment alter 5-HT1A receptor expression by modifying DNA methylation of a conserved Sp4 site.

    PubMed

    Le François, Brice; Soo, Jeremy; Millar, Anne M; Daigle, Mireille; Le Guisquet, Anne-Marie; Leman, Samuel; Minier, Frédéric; Belzung, Catherine; Albert, Paul R

    2015-10-01

    The serotonin 1A receptor (5-HT1A), a critical regulator of the brain serotonergic tone, is implicated in major depressive disorder (MDD) where it is often found to be dys-regulated. However, the extent to which stress and antidepressant treatment impact 5-HT1A expression in adults remains unclear. To address this issue, we subjected adult male BALB/c mice to unpredictable chronic mild stress (UCMS) to induce a depression-like phenotype that was reversed by chronic treatment with the antidepressant imipramine. In prefrontal cortex (PFC) and midbrain tissue, UCMS increased 5-HT1A RNA and protein levels, changes that are expected to decrease the brain serotonergic activity. The stress-induced increase in 5-HT1A expression was paralleled by a specific increase in DNA methylation of the conserved -681 CpG promoter site, located within a Sp1-like element. We show that the -681 CpG site is recognized and repressed by Sp4, the predominant neuronal Sp1-like factor and that Sp4-induced repression is attenuated by DNA methylation, despite a stress-induced increase in PFC Sp4 levels. These results indicate that adult life stress induces DNA methylation of a conserved promoter site, antagonizing Sp4 repression to increase 5-HT1A expression. Chronic imipramine treatment fully reversed the UCMS-induced increase in methylation of the -681 CpG site in the PFC but not midbrain of stressed animals and also increased 5-HT1A expression in the PFC of control animals. Incomplete reversal by imipramine of stress-induced changes in 5-HT1A methylation and expression indicates a persistence of stress vulnerability, and that sustained reversal of behavioral impairments may require additional pathways.

  9. A role for 5-HT1A receptors in the basolateral amygdala in the development of conditioned defeat in Syrian hamsters

    PubMed Central

    Morrison, Kathleen E.; Cooper, Matthew A.

    2011-01-01

    The basolateral nucleus of the amygdala (BLA) is a key brain region regulating behavioral changes following stressful events, including social defeat. Previous research has shown that activation of serotonin (5-HT) 1A receptors in the BLA reduces conditioned fear and anxiety-like behavior. The objective of this study was to test whether 5-HT1A receptors in the BLA contribute to conditioned defeat in male Syrian hamsters (Mesocricetus auratus). We tested whether injection of the selective 5-HT1A receptor agonist flesinoxan (400 ng, 800 ng, or 1200 ng in 200 nl saline) into the BLA prior to social defeat would reduce the acquisition of conditioned defeat, and whether a similar injection prior to testing would reduce the expression of conditioned defeat. We also tested whether injection of the selective 5-HT1A receptor antagonist WAY-100635 (400 ng or 1600 ng in 200 nl saline) into the BLA prior to social defeat would enhance the acquisition of conditioned defeat, and whether a similar injection prior to testing would enhance the expression of conditioned defeat. We found that injection of flesinoxan into the BLA decreased both the acquisition and expression of conditioned defeat. However, injection of WAY-100635 into the BLA did not alter the acquisition or expression of conditioned defeat. These data indicate that pharmacological activation of 5-HT1A receptors in the BLA is sufficient to impair the acquisition and expression of conditioned defeat. Our results suggest that pharmacological treatments that activate 5-HT1A receptors in the BLA are capable of reducing the development of stress-induced changes in behavior. PMID:21967885

  10. The Antidepressant-Like Effect of Fish Oil: Possible Role of Ventral Hippocampal 5-HT1A Post-synaptic Receptor.

    PubMed

    Carabelli, Bruno; Delattre, Ana Marcia; Pudell, Claudia; Mori, Marco Aurélio; Suchecki, Deborah; Machado, Ricardo B; Venancio, Daniel Paulino; Piazzetta, Sílvia Regina; Hammerschmidt, Ivilim; Zanata, Sílvio M; Lima, Marcelo M S; Zanoveli, Janaína Menezes; Ferraz, Anete Curte

    2015-08-01

    The pathophysiology of depression is not completely understood; nonetheless, numerous studies point to serotonergic dysfunction as a possible cause. Supplementation with fish oil rich docosahexaenoic (DHA) and eicosapentaenoic acids (EPA) during critical periods of development produces antidepressant effects by increasing serotonergic neurotransmission, particularly in the hippocampus. In a previous study, the involvement of 5-HT1A receptors was demonstrated and we hypothesized that fish oil supplementation (from conception to weaning) alters the function of post-synaptic hippocampal 5-HT1A receptors. To test this hypothesis, female rats were supplemented with fish oil during habituation, mating, gestation, and lactation. The adult male offspring was maintained without supplementation until 3 months of age, when they were subjected to the modified forced swimming test (MFST) after infusion of vehicle or the selective 5-HT1A antagonist, WAY100635, and frequency of swimming, immobility, and climbing was recorded for 5 min. After the behavioral test, the hippocampi were obtained for quantification of serotonin (5-HT) and its metabolite, 5-hydroxyindoleacetic acid (5-HIAA) and for 5-HT1A receptor expression by Western blotting analysis. Fish oil-supplemented offspring displayed less depressive-like behaviors in the MFST reflected by decreased immobility and increased swimming and higher 5-HT hippocampal levels. Although there was no difference in the expression of hippocampal 5-HT1A receptors, intra-hippocampal infusion of a sub-effective dose of 8-OH-DPAT enhanced the antidepressant effect of fish oil in supplemented animals. In summary, the present findings suggest that the antidepressant-like effects of fish oil supplementation are likely related to increased hippocampal serotonergic neurotransmission and sensitization of hippocampal 5-HT1A receptors.

  11. Interaction of 5-HT1B/D ligands with recombinant h 5-HT1A receptors: intrinsic activity and modulation by G-protein activation state.

    PubMed

    Pauwels, P J; Palmier, C; Dupuis, D S; Colpaert, F C

    1998-05-01

    Many 5-HT1B/D receptor ligands have affinity for 5-HT1A receptors. In the present study, the intrinsic activity of a series of 5-HT1B/D ligands was investigated at human 5-HT1A (h 5-HT1A) receptors by measuring G-protein activation in recombinant C6-glial and HeLa membranes, using agonist-stimulated [35S]GTPgammaS binding. In these two membrane preparations, the density of h 5-HT1A receptors (i.e., 246 to 320 fmol mg(-1) protein) and of their G-proteins, and the receptor: G-protein density ratio (0.08 to 0.18) appeared to be similar. It was found that: (i) the maximal [35S]GTPgammaS binding responses induced by the 5-HT1B/D receptor ligands in the HeLa preparation at 30 microM GDP were comparable to that of the native agonist 5-HT; (ii) as compared to 5-HT (1.00), similar potencies but lower maximal responses were observed in the C6-glial preparation at 0.3 microM GDP for zolmitriptan (0.89), dihydroergotamine (0.81), rizatriptan (0.71), CP122638 (0.69), naratriptan (0.60) and sumatriptan (0.53); and that (iii) maximal [35S]GTPgammaS binding responses induced by 5-HT1B/D ligands in the C6-glial preparation were either unaffected or significantly enhanced by increasing the GDP concentration from 0.3 to 30 microM and higher concentrations. These features differ from those observed with 5-HT1A receptor agonists; the latter display the same rank order of potency and efficacy in both membrane preparations, and increasing the amount of GDP with C6-glial membranes results in an attenuation of both the agonist's maximal effect and the apparent potency of partial agonists. The differential regulation of 5-HT1A and 5-HT1B/D agonist responses by GDP suggests that different G-protein subtypes are involved upon 5-HT1A receptor activation by 5-HT1A and 5-HT1B/D agonists. PMID:9650800

  12. Antipsychotics differ in their ability to internalise human dopamine D2S and human serotonin 5-HT1A receptors in HEK293 cells.

    PubMed

    Heusler, Peter; Newman-Tancredi, Adrian; Loock, Timothé; Cussac, Didier

    2008-02-26

    Antipsychotic drugs act preferentially via dopamine D(2) receptor blockade, but interaction with serotonin 5-HT(1A) receptors has attracted interest as additional target for antipsychotic treatment. As receptor internalisation is considered crucial for drug action, we tested the propensity of antipsychotics to internalise human (h)D(2S) receptors and h5-HT(1A) receptors. Agonist-induced internalisation of hemaglutinin (HA)-tagged hD(2S) and HA-h5-HT(1A) receptors expressed in HEK293 cells was increased by coexpression of G-protein coupled receptor kinase 2 and beta-arrestin2. At the HA-hD(2S) receptor, dopamine, quinpirole and bromocriptine behaved as full agonists, while S(-)-3-(3-hydroxyphenyl)-N-n-propylpiperidine [(-)-3PPP] and sarizotan were partial agonists. The typical antipsychotic, haloperidol, and the atypical compounds, olanzapine, nemonapride, ziprasidone and clozapine did not internalise HA-hD(2S) receptors, whereas aripiprazole potently internalised these receptors (>50% relative efficacy). Among antipsychotics with combined D(2)/5-HT(1A) properties, bifeprunox and (3-exo)-8-benzoyl-N-[[(2S)7-chloro-2,3-dihydro-1,4-benzodioxin-1-yl]methyl]-8-azabicyclo-[3.2.1]octane-3-methanamine (SSR181507) partially internalised HA-hD(2S) receptors, piperazine, 1-(2,3-dihydro-1,4-benzodioxin-5-yl)-4-[[5-(4-fluorophenyl)-3-pyridinyl]methyl (SLV313) and N-[(2,2-dimethyl-2,3-dihydro-benzofuran-7-yloxy)ethyl]-3-(cyclopent-1-enyl)-benzylamine (F15063) were inactive. At the HA-h5-HT(1A) receptor, serotonin, (+)-8-hydroxy-2-(di-n-propylamino)tetralin [(+)-8-OH-DPAT] and sarizotan were full agonists, buspirone acted as partial agonist. (-)-Pindolol showed little activity and no internalising properties were manifested for the 5-HT(1A) receptor antagonist N-[2-[4-(2-methoxyphenyl)-1-piperazinyl]-ethyl]-N-(2-pyridinyl)cyclohexanecarboxamide (WAY100635). Most antipsychotics induced HA-h5-HT(1A) receptor internalisation, with an efficacy rank order: nemonapride>F15063>SSR181507

  13. Differential involvement of 5-HT(1A) and 5-HT(1B/1D) receptors in human interferon-alpha-induced immobility in the mouse forced swimming test.

    PubMed

    Zhang, Hongmei; Wang, Wei; Jiang, Zhenzhou; Shang, Jing; Zhang, Luyong

    2010-01-01

    Although Interferon-alpha (IFN-alpha, CAS 9008-11-1) is a powerful drug in treating several viral infections and certain tumors, a considerable amount of neuropsychiatric side-effects such as depression and anxiety are an unavoidable consequence. Combination with the selective serotonin (5-HT) reuptake inhibitor (SSRI) fluoxetine (CAS 56296-78-7) significantly improved the situation. However, the potential 5-HT(1A) receptor- and 5-HT(1B) receptor-signals involved in the antidepressant effects are still unclear. The effects of 5-HT(1A) receptor- and 5-HT(1B) receptor signals were analyzed by using the mouse forced swimming test (FST), a predictive test of antidepressant-like action. The present results indicated that (1) fluoxetine (administrated intragastrically, 30 mg/kg; not subactive dose: 15 mg/kg) significantly reduced IFN-alpha-induced increase of the immobility time in the forced swimming test; (2) 5-HT(1A) receptor- and 5-HT(1B) receptor ligands alone or in combination had no effects on IFN-alpha-induced increase of the immobility time in the FST; (3) surprisingly, WAY 100635 (5-HT(1A) receptor antagonist, 634908-75-1) and 8-OH-DPAT(5-HT(1A) receptor agonist, CAS 78950-78-4) markedly enhanced the antidepressant effect of fluoxetine at the subactive dose (15 mg/kg, i. g.) on the IFN-alpha-treated mice in the FST. Further investigations showed that fluoxetine combined with WAY 100635 and 8-OH-DPAT failed to produce antidepressant effects in the FST. (4) Co-application of CGS 12066A (5-HT(1B) receptor agonist, CAS 109028-09-3) or GR 127935 (5-HT(1B/1D) receptor antagonist, CAS 148642-42-6) with fluoxetine had no synergistic effects on the IFN-alpha-induced increase of immobility time in FST. (5) Interestingly, co-administration of GR 127935, WAY 100635 and fluoxetine significantly reduced the IFN-alpha-induced increase in immobility time of FST, being more effective than co-administration of WAY 100635 and fluoxetine. All results suggest that (1) compared to

  14. Interaction between μ-opioid and 5-HT1A receptors in the regulation of panic-related defensive responses in the rat dorsal periaqueductal grey.

    PubMed

    Rangel, Marcel P; Zangrossi, Hélio; Roncon, Camila M; Graeff, Frederico G; Audi, Elisabeth A

    2014-12-01

    A wealth of evidence indicates that the activation of 5-HT1A and 5-HT2A receptors in the dorsal periaqueductal grey matter (dPAG) inhibits escape, a panic-related defensive behaviour. Results that were previously obtained with the elevated T-maze test of anxiety/panic suggest that 5-HT1A and μ-opioid receptors in this midbrain area work together to regulate this response. To investigate the generality of this finding, we assessed whether the same cooperative mechanism is engaged when escape is evoked by a different aversive stimulus electrical stimulation of the dPAG. Administration of the μ-receptor blocker CTOP into the dPAG did not change the escape threshold, but microinjection of the μ-receptor agonist DAMGO (0.3 and 0.5 nmol) or the 5-HT1A receptor agonist 8-OHDPAT (1.6 nmol) increased this index, indicating a panicolytic-like effect. Pretreatment with CTOP antagonised the anti-escape effect of 8-OHDPAT. Additionally, combined administration of subeffective doses of DAMGO and 8-OHDPAT increased the escape threshold, indicating drug synergism. Therefore, regardless of the aversive nature of the stimulus, μ-opioid and 5-HT1A receptors cooperatively act to regulate escape behaviour. A better comprehension of this mechanism might allow for new therapeutic strategies for panic disorder.

  15. The role of 5-HT1A receptors in mediating acute negative effects of antidepressants: implications in pediatric depression

    PubMed Central

    Rahn, K A; Cao, Y-J; Hendrix, C W; Kaplin, A I

    2015-01-01

    Acute antidepressant exposure elevates the frequency of impulsive behavior and suicidal thoughts in children and adolescents with major depressive disorder (MDD). Long-term antidepressant treatment, however, is beneficial for pediatric MDD, so it is necessary to explore novel treatments that prevent the potentially dangerous consequences of acute antidepressant initiation. In the present study, a treatment strategy designed to reverse the acute negative behavioral effects of antidepressants was tested in rodents. Co-administration of the 5-HT1A receptor (5-HT1AR) antagonist WAY-100635 reversed the negative effects of acute fluoxetine, a serotonin reuptake inhibitor, but not reboxetine, a norepinephrine reuptake inhibitor, supporting the involvement of 5-HT1AR in mediating the negative consequences of acute selective serotonin reuptake inhibitor (SSRI) treatment. No 5-HT1AR antagonists are currently approved for use in pediatric populations, so alternative strategies should be explored. One such strategy was suggested based on the hypothesis that the rate of 5-HT1AR activation and the subsequent inhibition of serotonergic neuron activity caused by acute SSRI administration is proportional to the loading rate of an antidepressant. Existing pharmacological data were examined, and significant correlations were observed between the half-life of antidepressants and the rate of suicide-related events (SREs). Specifically, antidepressants with longer half-lives have lower rates of SREs. On the basis of these data, novel dosing strategies were developed for five antidepressants to mimic the pharmacological profile of the antidepressant with the longest half-life, fluoxetine. These dosing strategies could be used to decrease the rate of SREs associated with acute antidepressant treatment in pediatric MDD until an improved pharmacological treatment is developed. PMID:25942044

  16. Agonist and antagonist bind differently to 5-HT1A receptors during Alzheimer's disease: A post-mortem study with PET radiopharmaceuticals.

    PubMed

    Vidal, Benjamin; Sebti, Johan; Verdurand, Mathieu; Fieux, Sylvain; Billard, Thierry; Streichenberger, Nathalie; Troakes, Claire; Newman-Tancredi, Adrian; Zimmer, Luc

    2016-10-01

    PET imaging studies using 5-HT1A receptor radiotracers show a decreased density of this receptor in hippocampi of patients with Alzheimer's disease (AD) at advanced stages. However, current 5-HT1A receptor radiopharmaceuticals used in neuroimaging are antagonists, thought to bind to 5-HT1A receptors in different functional states (i.e., both the one which displays high affinity for agonists and is thought to mediate receptor activation, as well as the state which has low affinity for agonists). Comparing the PET imaging obtained using an agonist radiotracer, which binds selectively to functional receptors, with the PET imaging obtained using an antagonist radiotracer would therefore provide original information on 5-HT1A receptor impairment during AD. Quantitative autoradiography using [(18)F]F13640 and [(18)F]MPPF, a 5-HT1A agonist and antagonist, respectively, was measured in hippocampi of patients with AD (n = 25, at different Braak stages) and control subjects (n = 9). The neuronal density was measured in the same tissues by NeuN immunohistochemistry. The specific binding of both radiotracers was determined by addition of WAY-100635, a selective 5-HT1A receptor antagonist. The autoradiography distribution of both 5-HT1A PET radiotracers varied across hippocampus regions. The highest binding density was in the pyramidal layer of CA1. Incubation with Gpp(NH)p, a non-hydrolysable analogue of GTP, reduced significantly [(18)F]F13640 binding in hippocampal regions, confirming its preferential interaction with G-coupled receptors, and slightly increased [(18)F]MPPF binding. In the CA1 subfield, [(18)F]F13640 binding was significantly decreased at Braak stages I/II (-19%), Braak stages III/IV (-23%), and Braak stages V/VI (-36%) versus control. In contrast, [(18)F]MPPF binding was statistically reduced only at the most advanced Braak stages V/VI compared to control (-33%). Since [(18)F]F13640 and [(18)F]MPPF can be used in vivo in humans, this

  17. 5-HT(1A)-receptor over-expressing mice: genotype and sex dependent responses to antidepressants in the forced swim-test.

    PubMed

    Günther, Lydia; Rothe, Julia; Rex, André; Voigt, Jörg-Peter; Millan, Mark J; Fink, Heidrun; Bert, Bettina

    2011-09-01

    Deficiencies in serotonergic neurotransmission are involved in the pathophysiology of depression. Due to its modulatory effect on serotonin (5-HT) release, the 5-HT(1A)-receptor is thought to play a decisive role in the therapy of this mood disorder. However, it is not fully understood how antidepressant effects are mediated by pre- and postsynaptic receptor sites. In this study we examined the impact of postsynaptic 5-HT(1A)-receptor over-expression in corticolimbic areas of male and female mice on the performance in the forced swim-test (FST). Furthermore, we investigated their response to the serotonin selective reuptake inhibitor (SSRI) citalopram in comparison to the selective noradrenaline reuptake inhibitor reboxetine, as well as the partial 5-HT(1A)-receptor agonists, buspirone and S 15535. Additionally, these drugs were evaluated in the open field-test in order to observe effects on motor activity. The density of 5-HT(1A)-receptors in discrete corticolimbic regions was determined in detail by quantitative autoradiography with [(3)H]8-OH-DPAT to investigate genotype as well as sex dependent differences in the expression pattern. [(3)H]8-OH-DPAT binding differed depending on sex with female mice of both genotypes displaying higher receptor binding in distinct brain areas. In the FST untreated male but not female over-expressing (OE) mice showed an antidepressant-like behaviour compared to wild-type (WT) mice. Citalopram yielded an antidepressant effect without influencing locomotor activity in OE mice but not in WT mice. Reboxetine had no antidepressant-like effect in OE mice, but sex-dependently in WT mice. The two partial agonists, buspirone and S 15535 produced no antidepressant-like activity in both genotypes and sexes, but aberrant motor effects. The antidepressant-like phenotype of male transgenic mice accounts for an involvement of postsynaptic 5-HT(1A)-receptors in the FST behaviour. In addition, the selective over-expression of postsynaptic 5-HT(1A)-receptors

  18. 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.

  19. Similar anxiolytic effects of agonists targeting serotonin 5-HT1A or cannabinoid CB receptors on zebrafish behavior in novel environments

    PubMed Central

    Connors, Kristin A.; Valenti, Theodore W.; Lawless, Kelly; Sackerman, James; Onaivi, Emmanuel S.; Brooks, Bryan W.; Gould, Georgianna G.

    2014-01-01

    The discovery that selective serotonin reuptake inhibitors (SSRIs) such as fluoxetine are present and bioaccumulate in aquatic ecosystems have spurred studies of fish serotonin transporters (SERTs) and changes in SSRI-sensitive behaviors as adverse outcomes relevant for risk assessment. Many SSRIs also act at serotonin 5-HT1A receptors. Since capitolizing on this action may improve treatments of clinical depression and other psychiatric disorders, novel multimodal drugs that agonize 5-HT1A and block SERT were introduced. In mammals both 5-HT1A and CB agonists, such as buspirone and WIN55,212-2, reduce anxious behaviors. Immunological and behavioral evidence suggests that 5-HT1A-like receptors may function similarly in zebrafish (Danio rerio), yet their pharmacological properties are not well characterized. Herein we compared the density of [3H] 8-hydroxy-2-di-n-propylamino tetralin (8-OH-DPAT) binding to 5-HT1A-like sites in the zebrafish brain, to that of simalarly Gαi/o-coupled cannabinoid receptors. [3H] 8-OH-DPAT specific binding was 176 ± 8, 275 ± 32, and 230 ± 36 fmol/mg protein in the hypothalamus, optic tectum, and telencephalon. [3H] WIN55,212-2 binding density was higher in those same brain regions at 6 ± 0.3, 5.5 ± 0.4 and 7.3 ± 0.3 pm/mg protein. The aquatic light-dark plus maze was used to examine behavioral effects of 5-HT1A and CB receptor agonists on zebrafish novelty-based anxiety. With acute exposure to the 5-HT1A partial-agonist buspirone (50 mg/L), or dietary exposure to WIN55,212-2 (7 μg/week) zebrafish spent more time in and/or entered white arms more often than controls (p < 0.05). Acute exposure to WIN55,212-2 at 0.5-50 mg/L, reduced mobility. These behavioral findings suggest that azipirones, like cannabinoid agonists, have anxiolytic and/or sedative properties on fish in novel environments. These observations highlight the need to consider potential ecological risks of azapirones and multimodal antidepressants in the future. PMID

  20. [CROSS-TALK BETWEEN 5-HT1A AND 5-HT7 RECEPTORS: ROLE IN THE AUTOREGULATION OF THE BRAIN SEROTONIN SYSTEM AND IN MECHANISM OF ANTIDEPRESSANTS ACTION].

    PubMed

    Popova, N K; Ponimaskin, E G; Naumenko, V S

    2015-11-01

    Recent studies considerably extended our knowledge of the mechanisms and physiological role of the interaction between different receptors in the brain. Current review summarizes data on the formation of receptor complexes and the role of such complexes in the autoregulation of the brain serotonin system, behavioral abnormalities and mechanism of antidepressants action. Particular attention is paid to 5-HT1A and 5-HT7 receptor heterodimers. The results described in the present review indicate that: i) dimerization and formation of mobile receptor complexes is a common feature for the members of G-protein coupled receptor superfamily; ii) 5-HT7 receptor appears to be a modulator for 5-HT1A receptor - the key autoregulator of the brain serotonin system; iii) 5-HT1A/5-HT7 receptor complexes formation is one of the mechanisms for inactivation and desensitization of the 5-HTIA receptors in the brain; iv) differences in the 5-HT7 receptor and 5-HTIA/5-HT7 heterodimers density define different sensitivity of pre- and postsynaptic 5-HTlA receptors to chronic treatment with selective serotonin reuptake inhibitors.

  1. Potentiating action of MKC-242, a selective 5-HT1A receptor agonist, on the photic entrainment of the circadian activity rhythm in hamsters.

    PubMed

    Moriya, T; Yoshinobu, Y; Ikeda, M; Yokota, S; Akiyama, M; Shibata, S

    1998-11-01

    Serotonergic projections from the midbrain raphe nuclei to the suprachiasmatic nuclei (SCN) are known to regulate the photic entrainment of circadian clocks. However, it is not known which 5-hydroxytryptamine (5-HT) receptor subtypes are involved in the circadian regulation. In order to verify the role of 5-HT1A receptors, we examined the effects of 5-¿3-[((2S)-1,4-benzodioxan-2-ylmethyl)amino]-propoxy¿-1,3-b enzodioxole HCl (MKC-242), a selective 5-HT1A receptor agonist, on photic entrainment of wheel-running circadian rhythms of hamsters. MKC-242 (3 mg kg(-1), i.p.) significantly accelerated the re-entrainment of wheel-running rhythms to a new 8 h delayed or advanced light-dark cycle. MKC-242 (3 mg kg(-1), i.p.) also potentiated the phase advance of the wheel-running rhythm produced by low (5 lux) or high (60 lux) intensity light pulses. In contrast, 8-hydroxydipropylaminotetralin (8-OH-DPAT)(5 mg kg(-1), i.p.), a well known 5-HT1A/5-HT7 receptor agonist, only suppressed low intensity (5 lux) light-induced phase advances. The potentiating actions of MKC-242 on light pulse-induced phase advances were observed even when injected 20 or 60 min after the light exposure. The potentiating action of MKC-242 was antagonized by WAY100635, a selective 5-HT1A receptor blocker, but not by ritanserin, a 5-HT2/5-HT7 receptor blocker, indicating that MKC-242 is activating 5-HT1A receptors. Light pulse-induced c-fos expression in the SCN and the intergeniculate leaflet (IGL) were unaffected by MKC-242 (3 mg kg(-1), i.p.). HPLC analysis demonstrated that MKC-242 (3 mg kg(-1), i.p.) decreased the 5-HIAA content in the SCN. The present results suggest that presynaptic 5-HT1A receptor activation may be involved in the potentiation of photic entrainment by MKC-242 in hamsters. PMID:9863658

  2. Potentiating action of MKC-242, a selective 5-HT1A receptor agonist, on the photic entrainment of the circadian activity rhythm in hamsters

    PubMed Central

    Moriya, T; Yoshinobu, Y; Ikeda, M; Yokota, S; Akiyama, M; Shibata, S

    1998-01-01

    Serotonergic projections from the midbrain raphe nuclei to the suprachiasmatic nuclei (SCN) are known to regulate the photic entrainment of circadian clocks. However, it is not known which 5-hydroxytryptamine (5-HT) receptor subtypes are involved in the circadian regulation. In order to verify the role of 5-HT1A receptors, we examined the effects of 5-{3-[((2S)-1,4-benzodioxan-2-ylmethyl)amino]propoxy}-1,3-benzodioxole HCl (MKC-242), a selective 5-HT1A receptor agonist, on photic entrainment of wheel-running circadian rhythms of hamsters.MKC-242 (3 mg kg−1, i.p.) significantly accelerated the re-entrainment of wheel-running rhythms to a new 8 h delayed or advanced light-dark cycle.MKC-242 (3 mg kg−1, i.p.) also potentiated the phase advance of the wheel-running rhythm produced by low (5 lux) or high (60 lux) intensity light pulses. In contrast, 8-hydroxy-dipropylaminotetralin (8-OH-DPAT)(5 mg kg−1, i.p.), a well known 5-HT1A/5-HT7 receptor agonist, only suppressed low intensity (5 lux) light-induced phase advances.The potentiating actions of MKC-242 on light pulse-induced phase advances were observed even when injected 20 or 60 min after the light exposure.The potentiating action of MKC-242 was antagonized by WAY100635, a selective 5-HT1A receptor blocker, but not by ritanserin, a 5-HT2/5-HT7 receptor blocker, indicating that MKC-242 is activating 5-HT1A receptors.Light pulse-induced c-fos expression in the SCN and the intergeniculate leaflet (IGL) were unaffected by MKC-242 (3 mg kg−1, i.p.).HPLC analysis demonstrated that MKC-242 (3 mg kg−1, i.p.) decreased the 5-HIAA content in the SCN.The present results suggest that presynaptic 5-HT1A receptor activation may be involved in the potentiation of photic entrainment by MKC-242 in hamsters. PMID:9863658

  3. 5-HT1A and benzodiazepine receptors in the basolateral amygdala modulate anxiety in the social interaction test, but not in the elevated plus-maze.

    PubMed

    Gonzalez, L E; Andrews, N; File, S E

    1996-09-01

    In order to investigate the role of the 5-HT1A receptors of the amygdala in modulating anxiety, rats were implanted with bilateral cannulae aimed at the basolateral nucleus of the amygdala complex and infused with either artificial cerebrospinal fluid (aCSF) or the selective 5-HT1A receptor agonist 8-OH-DPAT (50-200 ng) and tested in two animal models of anxiety. In the elevated plus-maze test, no significant effects were detected in this dose range. In contrast, 8-OH-DPAT caused an overall reduction in levels of social investigation, thus indicating anxiogenic actions in the social interaction test. At 50 ng, 8-OH-DPAT had a selective action on anxiety, while at 200 ng there was a concomitant reduction in locomotor activity and, in some animals, signs of the 5-HT1A syndrome. Evidence that the anxiogenic effect of 8-OH-DPAT (50 ng) was due to activation of 5-HT1A receptors came from the finding that (-)-tertatolol, a 5-HT1A receptor antagonist, reversed this effect at a dose (1.5 micrograms) which was silent when given alone. The benzodiazepine receptor agonist, midazolam (1 and 2 micrograms) was bilaterally administered into the basolateral nucleus of the amygdala and evoked clear-cut anxiolytic effects in the social interaction test. These data indicate that the agonist activation of post-synaptic 5-HT1A receptors in the basolateral nucleus of the amygdala may produce anxiogenic effects, while agonist activation of BDZ receptors in the same areas evokes anxiolytic effects. Our results from the social interaction test are similar to those previously reported from tests of anxiety using punished paradigms, but contrast with those found in the elevated plus-maze. Thus, it is concluded that either the two tests have different sensitivities to midazolam and 8-OH-DPAT or more intriguingly, the tests are evoking fundamentally different states of anxiety, with that evoked by the plus-maze being mediated via brain areas or receptors different from those studied here.

  4. Uncoupling of 5-HT1A receptors in the brain by estrogens: regional variations in antagonism by ICI 182,780.

    PubMed

    Mize, A L; Young, L J; Alper, R H

    2003-04-01

    Previously we have shown that 17beta-estradiol (in vivo and in vitro) rapidly decreases the function of serotonin(1A) (5-HT(1A)) receptors, allowing us to hypothesize that 17beta-estradiol accomplished this via activation of a membrane estrogen receptor. Hippocampus and frontal cortex obtained from ovariectomized rats were incubated with 17beta-estradiol or bovine serum albumin (BSA)-estradiol in the presence or absence of the estrogen receptor (ER) antagonist ICI 182,780. Membranes were prepared to measure R(+)8-OH-DPAT-stimulated [(35)S]GTPgammaS binding (a measure of 5-HT(1A) receptor coupling and function). In both hippocampus and frontal cortex, 17beta-estradiol and BSA-estradiol (50 nM) decreased R(+)8-OH-DPAT-stimulated [(35)S]GTPgammaS binding. ICI 182,780 blocked the effect of both the estrogens in hippocampus, but only the effect of 17beta-estradiol in frontal cortex. Due to the inability of ICI 182,780 to block the effects of BSA-estradiol in frontal cortex, similar experiments were performed using the selective estrogen receptor modulator tamoxifen as the agonist. Tamoxifen (100 nM and 1 microM) decreased R(+)8-OH-DPAT-stimulated [(35)S]GTPgammaS binding. ICI 182,780 (1 microM) blocked the ability of tamoxifen to decrease 5-HT(1A) receptor coupling in the hippocampus, but not in the frontal cortex. Taken together, these data support the existence of a pharmacologically distinct ER in hippocampus vs. frontal cortex that might be responsible for rapid uncoupling of 5-HT(1A) receptors. PMID:12668044

  5. Interaction of the alpha-adrenoceptor agonist oxymetazoline with serotonin 5-HT1A, 5-HT1B, 5-HT1C and 5-HT1D receptors.

    PubMed

    Schoeffter, P; Hoyer, D

    1991-04-17

    Oxymetazoline was recognized with nanomolar affinity by 5-HT1A, 5-HT1B and 5-HT1D binding sites and mimicked the effects of 5-hydroxytryptamine with about the same potency and intrinsic activity as the endogenous amine in the corresponding functional tests. At 5-HT1C receptors, oxymetazoline behaved as a mixed agonist-antagonist. Clonidine had minimal activity. Methiothepin antagonized the effects of oxymetazoline (7.4 less than pKB less than 8.8). Thus, oxymetazoline is a full and potent agonist at 5-HT1A, 5-HT1B and 5-HT1D receptors and a partial agonist at 5-HT1C receptors.

  6. Effect of selective agonist of serotonin 5-HT1A receptors on defensive behavior in mice with different predisposition to catalepsy.

    PubMed

    Bazovkina, D V; Terenina, E E; Kulikov, A V

    2010-12-01

    We studied the effect of activation of serotonin 5-HT1A receptors with selective agonist 8-OH-DPAT (0.1, 0.5, and 1.0 mg/kg) on intraspecies aggression and freezing reaction (catalepsy) in male mice of catalepsy-resistant AKR/J and two catalepsy-prone strains CBA/Lac and congenic AKR.CBA-D13Mit76. The latter strain differs from AKR strain only by terminal chromosome 13 fragment transferred from CBA strain and containing a locus determining predisposition to catalepsy and a gene encoding 5-HT1A receptor. 8-OH-DPAT in a low dose (0.1 mg/kg) affecting primarily presynaptic receptors suppressed aggressive behavior in CBA mice, but had no effect on the time of cataleptic freezing. At the same time, this dose of the drug produced no significant effect on aggression in AKR and AKR.CBA-D13Mit76 mice, but significantly attenuated freezing in AKR.CBA-D13Mit76 mice. High doses of 8-OH-DPAT (0.5 and 1 mg/kg) which affected mainly postsynaptic receptors inhibited catalepsy in CBA and AKR.CBA-D13Mit76 mice and in a dose of 1 mg/kg it suppressed aggression in all tested mouse strains. We concluded that the genome of the recipient strain (AKR) modulated the involvement of 5-HT(1A) receptors into the regulation of aggression and catalepsy in mice.

  7. Isoquinoline derivatives isolated from the fruit of Annona muricata as 5-HTergic 5-HT1A receptor agonists in rats: unexploited antidepressive (lead) products.

    PubMed

    Hasrat, J A; De Bruyne, T; De Backer, J P; Vauquelin, G; Vlietinck, A J

    1997-11-01

    The fruit and the leaves of Annona muricata (Annonaceae) are used in traditional medicine for their tranquillizing and sedative properties. Extracts of the plant have been shown to inhibit binding of [3H]rauwolscine to 5-HTergic 5-HT1A receptors in calf hippocampus, and three alkaloids, annonaine (1), nornuciferine (2) and asimilobine (3), isolated from the fruit have been shown to have IC50 values of 3 microM, 9 microM and 5 microM, respectively, although in ligand-binding studies it was not possible to determine whether interaction of these ligands with the receptor was agonistic or antagonistic. This paper presents the results of functional assays of the alkaloids. The inhibition of cAMP accumulation was tested in NIH-3T3 cells stably transfected with the 5-HT1A receptor from man. None of the alkaloids showed antagonistic properties towards the 5-HT1A receptors because in the antagonistic tests no influence on the forskolin-stimulated increase of cAMP level was detected. Full agonistic properties were measured for all three compounds; the inhibition constants (Ki) for 1, 2 and 3 were < 10 microM. Inhibition of the binding of the radioligand to the 5-HT1A receptor was observed in every ligand-binding assay performed with the alkaloids; the Ki values for 1, 2 and 3 were in the microM range. These results imply that the fruit of Annona muricata possesses anti-depressive effects, possibly induced by compounds 1, 2 and 3, and that in the past potent leads for the development of anti-depressive therapeutics have not been used.

  8. Isoquinoline derivatives isolated from the fruit of Annona muricata as 5-HTergic 5-HT1A receptor agonists in rats: unexploited antidepressive (lead) products.

    PubMed

    Hasrat, J A; De Bruyne, T; De Backer, J P; Vauquelin, G; Vlietinck, A J

    1997-11-01

    The fruit and the leaves of Annona muricata (Annonaceae) are used in traditional medicine for their tranquillizing and sedative properties. Extracts of the plant have been shown to inhibit binding of [3H]rauwolscine to 5-HTergic 5-HT1A receptors in calf hippocampus, and three alkaloids, annonaine (1), nornuciferine (2) and asimilobine (3), isolated from the fruit have been shown to have IC50 values of 3 microM, 9 microM and 5 microM, respectively, although in ligand-binding studies it was not possible to determine whether interaction of these ligands with the receptor was agonistic or antagonistic. This paper presents the results of functional assays of the alkaloids. The inhibition of cAMP accumulation was tested in NIH-3T3 cells stably transfected with the 5-HT1A receptor from man. None of the alkaloids showed antagonistic properties towards the 5-HT1A receptors because in the antagonistic tests no influence on the forskolin-stimulated increase of cAMP level was detected. Full agonistic properties were measured for all three compounds; the inhibition constants (Ki) for 1, 2 and 3 were < 10 microM. Inhibition of the binding of the radioligand to the 5-HT1A receptor was observed in every ligand-binding assay performed with the alkaloids; the Ki values for 1, 2 and 3 were in the microM range. These results imply that the fruit of Annona muricata possesses anti-depressive effects, possibly induced by compounds 1, 2 and 3, and that in the past potent leads for the development of anti-depressive therapeutics have not been used. PMID:9401954

  9. Involvement of the serotonergic type 1A (5-HT1A) receptor in the agranular insular cortex in the consolidation of memory for inhibitory avoidance in rats.

    PubMed

    Mello e Souza, T; Rodrigues, C; Souza, M M; Vinadé, E; Coitinho, A; Choi, H; Izquierdo, I

    2001-09-01

    Adult male Wistar rats were bilaterally implanted with indwelling cannulae in the agranular insular cortex of the prefrontal cortex. After recovery, animals were trained in a step-down inhibitory avoidance task (3.0-s, 0.4-mA footshock) and received, immediately after training, a 0.5-microl infusion of the serotonergic type 1A (5-HT1A) receptor agonist dipropylamino-8-hydroxy-1,2,3,4-tetrahydronaphthalene hydrobromide (8-OH-DPAT) or of the 5- HT1A receptor antagonist 1-(2-methoxyphenyl)-4-[4-(2-phthalimido)butyl] piperazine hydrobromide (NAN-190), or of vehicle alone (20% DMSO). Retention testing was carried out 24 h after training. 8-OH-DPAT (1.25 and 6.25 microg but not 0.0125 or 0.125 microg) was amnesic. NAN-190 was not effective at 0.125 or 1.25 microg any dose but reversed amnesia when given at 1.250 microg simultaneously with both effective doses of 8-OH-DPAT. These results show that an overactivation of 5-HT1A receptors in the agranular insular cortex impairs memory consolidation of inhibitory avoidance, in rats, immediately after training. This suggests that these receptors of the insular cortex may modulate memory consolidation.

  10. Long-Term Citalopram Treatment Alters the Stress Responses of the Cortical Dopamine and Noradrenaline Systems: the Role of Cortical 5-HT1A Receptors

    PubMed Central

    Kaneko, Fumi; Kishikawa, Yuki; Hanada, Yuuki; Yamada, Makiko; Kakuma, Tatsuyuki; Kawahara, Hiroshi; Nishi, Akinori

    2016-01-01

    Background: Cortical dopamine and noradrenaline are involved in the stress response. Citalopram, a selective serotonin reuptake inhibitor, has direct and indirect effects on the serotonergic system. Furthermore, long-term treatment with citalopram affects the dopamine and noradrenaline systems, which could contribute to the therapeutic action of antidepressants. Methods: The effects of long-term treatment with citalopram on the responses of the dopamine and noradrenaline systems in the rat prefrontal cortex to acute handling stress were evaluated using in vivo microdialysis. Results: Acute handling stress increased dopamine and noradrenaline levels in the prefrontal cortex. The dopamine and noradrenaline responses were suppressed by local infusion of a 5-HT1A receptor agonist, 7-(Dipropylamino)-5,6,7,8-tetrahydronaphthalen-1-ol;hydrobromide, into the prefrontal cortex. The dopamine response was abolished by long-term treatment with citalopram, and the abolished dopamine response was reversed by local infusion of a 5-HT1A receptor antagonist, (Z)-but-2-enedioic acid;N-[2-[4-(2-methoxyphenyl)piperazin-1-yl]ethyl]-N-pyridin-2-ylcyclohexanecarboxamide into the prefrontal cortex. On the other hand, long-term treatment with citalopram reduced the basal noradrenaline levels (approximately 40% of the controls), but not the basal dopamine levels. The noradrenaline response was maintained despite the low basal noradrenaline levels. Signaling from the 5-HT1A receptors and α2-adrenoceptors was not involved in the decrease in the basal noradrenaline levels but partially affected the noradrenaline response. Conclusions: Chronic citalopram treatment differentially suppresses the dopamine and noradrenaline systems in the prefrontal cortex, and the dopamine stress response was preferentially controlled by upregulating 5-HT1A receptor signaling. Our findings provide insight into how antidepressants modulate the dopamine and noradrenaline systems to overcome acute stress. PMID

  11. 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. PMID:27131780

  12. Cannabidiol induces rapid-acting antidepressant-like effects and enhances cortical 5-HT/glutamate neurotransmission: role of 5-HT1A receptors.

    PubMed

    Linge, Raquel; Jiménez-Sánchez, Laura; Campa, Leticia; Pilar-Cuéllar, Fuencisla; Vidal, Rebeca; Pazos, Angel; Adell, Albert; Díaz, Álvaro

    2016-04-01

    Cannabidiol (CBD), the main non-psychotomimetic component of marihuana, exhibits anxiolytic-like properties in many behavioural tests, although its potential for treating major depression has been poorly explored. Moreover, the mechanism of action of CBD remains unclear. Herein, we have evaluated the effects of CBD following acute and chronic administration in the olfactory bulbectomy mouse model of depression (OBX), and investigated the underlying mechanism. For this purpose, we conducted behavioural (open field and sucrose preference tests) and neurochemical (microdialysis and autoradiography of 5-HT1A receptor functionality) studies following treatment with CBD. We also assayed the pharmacological antagonism of the effects of CBD to dissect out the mechanism of action. Our results demonstrate that CBD exerts fast and maintained antidepressant-like effects as evidenced by the reversal of the OBX-induced hyperactivity and anhedonia. In vivo microdialysis revealed that the administration of CBD significantly enhanced serotonin and glutamate levels in vmPFCx in a different manner depending on the emotional state and the duration of the treatment. The potentiating effect upon neurotransmitters levels occurring immediately after the first injection of CBD might underlie the fast antidepressant-like actions in OBX mice. Both antidepressant-like effect and enhanced cortical 5-HT/glutamate neurotransmission induced by CBD were prevented by 5-HT1A receptor blockade. Moreover, adaptive changes in pre- and post-synaptic 5-HT1A receptor functionality were also found after chronic CBD. In conclusion, our findings indicate that CBD could represent a novel fast antidepressant drug, via enhancing both serotonergic and glutamate cortical signalling through a 5-HT1A receptor-dependent mechanism.

  13. Early-life stress induces persistent alterations in 5-HT1A receptor and serotonin transporter mRNA expression in the adult rat brain

    PubMed Central

    Bravo, Javier A.; Dinan, Timothy G.; Cryan, John F.

    2014-01-01

    Early-life experience plays a major role in the stress response throughout life. Neonatal maternal separation (MS) is an animal model of depression with an altered serotonergic response. We hypothesize that this alteration may be caused by differences in 5-HT1A receptor and serotonin transporter (SERT) mRNA expression in brain areas involved in the control of emotions, memory, and fear as well as in regions controlling the central serotonergic tone. To test this, Sprague–Dawley rats were subjected to MS for 3 h daily during postnatal days 2–12. As control, age matched rats were non-separated (NS) from their dams. When animals reached adulthood (11–13 weeks) brain was extracted and mRNA expression of 5-HT1A receptor in amygdala, hippocampus and dorsal raphé nucleus (DRN) and SERT in the DRN was analyzed through in situ hybridisation. Densitometric analysis revealed that MS increased 5-HT1A receptor mRNA expression in the amygdala, and reduced its expression in the DRN, but no changes were observed in the hippocampus in comparison to NS controls. Also, MS reduced SERT mRNA expression in the DRN when compared to NS rats. These results suggest that early-life stress induces persistent changes in 5-HT1A receptor and SERT mRNA expression in key brain regions involved in the development of stress-related psychiatric disorders. The reduction in SERT mRNA indicates an alteration that is in line with clinical findings such as polymorphic variants in individuals with higher risk of depression. These data may help to understand how early-life stress contributes to the development of mood disorders in adulthood. PMID:24782706

  14. Escitalopram attenuates β-amyloid-induced tau hyperphosphorylation in primary hippocampal neurons through the 5-HT1A receptor mediated Akt/GSK-3β pathway.

    PubMed

    Wang, Yan-Juan; Ren, Qing-Guo; Gong, Wei-Gang; Wu, Di; Tang, Xiang; Li, Xiao-Li; Wu, Fang-Fang; Bai, Feng; Xu, Lin; Zhang, Zhi-Jun

    2016-03-22

    Tau hyperphosphorylation is an important pathological feature of Alzheimer's disease (AD). To investigate whether escitalopram could inhibit amyloid-β (Aβ)-induced tau hyperphosphorylation and the underlying mechanisms, we treated the rat primary hippocampal neurons with Aβ1-42 and examined the effect of escitalopram on tau hyperphosphorylation. Results showed that escitalopram decreased Aβ1-42-induced tau hyperphosphorylation. In addition, escitalopram activated the Akt/GSK-3β pathway, and the PI3K inhibitor LY294002 blocked the attenuation of tau hyperphosphorylation induced by escitalopram. Moreover, the 5-HT1A receptor agonist 8-OH-DPAT also activated the Akt/GSK-3β pathway and decreased Aβ1-42-induced tau hyperphosphorylation. Furthermore, the 5-HT1A receptor antagonist WAY-100635 blocked the activation of Akt/GSK-3β pathway and the attenuation of tau hyperphosphorylation induced by escitalopram. Finally, escitalopram improved Aβ1-42 induced impairment of neurite outgrowth and spine density, and reversed Aβ1-42 induced reduction of synaptic proteins. Our results demonstrated that escitalopram attenuated Aβ1-42-induced tau hyperphosphorylation in primary hippocampal neurons through the 5-HT1A receptor mediated Akt/GSK-3β pathway. PMID:26950279

  15. Preclinical characterization of WAY-211612: a dual 5-HT uptake inhibitor and 5-HT1A receptor antagonist and potential novel antidepressant

    PubMed Central

    Beyer, CE; Lin, Q; Platt, B; Malberg, J; Hornby, G; Sullivan, KM; Smith, DL; Lock, T; Mitchell, PJ; Hatzenbuhler, NT; Evrard, DA; Harrison, BL; Magolda, R; Pangalos, MN; Schechter, LE; Rosenzweig-Lipson, S; Andree, TH

    2009-01-01

    Background and purpose As a combination of 5-HT selective reuptake inhibitor (SSRI) with 5-HT1A receptor antagonism may yield a rapidly acting antidepressant, WAY-211612, a compound with both SSRI and 5-HT1A receptor antagonist activities, was evaluated in preclinical models. Experimental approach Occupancy studies confirmed the mechanism of action of WAY-211612, while its in vivo profile was characterized in microdialysis and behavioural models. Key results WAY-211612 inhibited 5-HT reuptake (Ki = 1.5 nmol·L−1; KB = 17.7 nmol·L−1) and exhibited full 5-HT1A receptor antagonist activity (Ki = 1.2 nmol·L−1; KB = 6.3 nmol·L−1; Imax 100% in adenyl cyclase assays; KB = 19.8 nmol·L−1; Imax 100% in GTPγS). WAY-211612 (3 and 30 mg·kg−1, po) occupied 5-HT reuptake sites in rat prefrontal cortex (56.6% and 73.6% respectively) and hippocampus (52.2% and 78.5%), and 5-HT1A receptors in the prefrontal cortex (6.7% and 44.7%), hippocampus (8.3% and 48.6%) and dorsal raphe (15% and 83%). Acute or chronic treatment with WAY-211612 (3–30 mg·kg−1, po) raised levels of cortical 5-HT approximately twofold, as also observed with a combination of an SSRI (fluoxetine; 30 mg·kg−1, s.c.) and a 5-HT1A antagonist (WAY-100635; 0.3 mg·kg−1, s.c). WAY-211612 (3.3–30 mg·kg−1, s.c.) decreased aggressive behaviour in the resident-intruder model, while increasing the number of punished crossings (3–30 mg·kg−1, i.p. and 10–56 mg·kg−1, po) in the mouse four-plate model and decreased adjunctive drinking behaviour (56 mg·kg−1, i.p.) in the rat scheduled-induced polydipsia model. Conclusions and implications These findings suggest that WAY-211612 may represent a novel antidepressant. PMID:19338583

  16. Autoradiography of serotonin 5-HT1A receptor-activated G proteins in guinea pig brain sections by agonist-stimulated [35S]GTPgammaS binding.

    PubMed

    Dupuis, D S; Palmier, C; Colpaert, F C; Pauwels, P J

    1998-03-01

    G protein activation mediated by serotonin 5-HT1A and 5-HT(1B/D) receptors in guinea pig brain was investigated by using quantitative autoradiography of agonist-stimulated [35S]GTPgammaS binding to brain sections. [35S]GTPgammaS binding was stimulated by the mixed 5-HT1A/5-HT(1B/D) agonist L694247 in brain structures enriched in 5-HT1A binding sites, i.e., hippocampus (+140 +/- 14%), dorsal raphe (+70 +/- 8%), lateral septum (+52 +/- 12%), cingulate (+36 +/- 8%), and entorhinal cortex (+34 +/- 5%). L694247 caused little or no stimulation of [35S]GTPgammaS binding in brain regions with high densities of 5-HT(1B/D) binding sites (e.g., substantia nigra, striatum, central gray, and dorsal subiculum). The [35S]GTPgammaS binding response was antagonized by WAY100635 (10 microM) and methiothepin (10 microM). In contrast, the 5-HT1B inverse agonist SB224289 (10 microM) did not affect the L694247-mediated [35S]GTPgammaS binding response, and the mixed 5-HT(1B/D) antagonist GR127935 (10 microM) yielded a partial blockade. The distribution pattern of the [35S]GTPgammaS binding response and the antagonist profile suggest the L694247-mediated response in guinea pig brain to be mediated by 5-HT1A receptors. In addition to L694247, 8-hydroxy-2-(di-n-propylamino)tetralin, and flesinoxan also stimulated [35S]GTPgammaS binding; their maximal responses varied between 46 and 52% compared with L694247, irrespective of the brain structure being considered. Sumatriptan, rizatriptan, and zolmitriptan (10 microM) stimulated [35S]GTPgammaS binding in the hippocampus by 20-50%. Naratriptan, CP122638, and dihydroergotamine stimulated [35S]GTPgammaS binding to a similar level as L694247 in hippocampus, lateral septum, and dorsal raphe. It appears that under the present experimental conditions, G protein activation through 5-HT1A but not 5-HT(1B/D) receptors can be measured in guinea pig brain sections. PMID:9489749

  17. Role of 5-HT(1A) and 5-HT(1B) receptors in the antidepressant-like effect of piperine in the forced swim test.

    PubMed

    Mao, Qing-Qiu; Huang, Zhen; Ip, Siu-Po; Xian, Yan-Fang; Che, Chun-Tao

    2011-10-24

    Our previous studies have showed that treating mice with piperine significantly decreased the immobility time of the animals in the forced swim test and tail suspension test, which was related to up-regulation of serotonin (5-HT) level in the brain. The purpose of this study is to explore the contribution of 5-HT receptors in the antidepressant-like effect of piperine. The results showed that pre-treating mice with methiothepin (a non-selective 5-HT receptor antagonist, 0.1mg/kg, intraperitoneally), 4-(2'-methoxy-phenyl)-1-[2'-(n-2″-pyridinyl)-p-iodobenzamino-]ethyl-piperazine (a selective 5-HT(1A) receptor antagonist, 1mg/kg, subcutaneously) or 1-(2-(1-pyrrolyl)-phenoxy)-3-isopropylamino-2-propanol (a 5-HT(1B) receptor antagonist, 2.5mg/kg, intraperitoneally) was found to abolish the anti-immobility effect of piperine (10mg/kg, intraperitoneally) in the forced swim test. On the other hand, a sub-effective dose of piperine (1mg/kg, intraperitoneally) produced a synergistic antidepressant-like effect with (+)-8-hydroxy-2-(di-n-propylamino)tetralin (a 5-HT(1A) receptor agonist, 1mg/kg, intraperitoneally) or anpirtoline (a 5-HT(1B) receptor agonist, 0.25mg/kg, intraperitoneally). Taken together, these results suggest that the antidepressant-like effect of piperine in the mouse forced swim test may be mediated, at least in part, by the activation of 5-HT(1A) and 5-HT(1B) receptors.

  18. Influences of housing conditions and ethanol intake on binding characteristics of D2, 5-HT1A, and benzodiazepine receptors of rats.

    PubMed

    Rilke, O; May, T; Oehler, J; Wolffgramm, J

    1995-09-01

    The effects of different housing conditions and ethanol treatment (6 vol % in the drinking water) on the in vitro binding characteristics of striatal dopaminergic D2 ([3H]spiperone), hippocampal serotonergic 5-HT1A ([3H]8-OH-DPAT), and cortical benzodiazepine ([3H]flunitrazepam) receptors have been examined. Social deprivation due to contact caging, short- (1 day) and long-term isolation (5 weeks) yielded a significant decrease of striatal D2 receptor density with the greatest decrease after long-term isolation (-21% Bmax) without changes of Kd in comparison to group animals. The effect of ethanol on striatal D2 receptor density depended on the housing conditions. Whereas ethanol treatment reduced receptor density of group animals (down to 88%), chronic exposure to ethanol under long-term isolation elicited no significant alteration of D2 receptor density compared with group animals. Different housing and ethanol treatment had no effect on 5-HT1A receptor affinity and density. Alterations of benzodiazepine receptor density were not found, but social deprivation as well as ethanol treatment of group animals caused an increased affinity of [3H]flunitrazepam (reduced Kd value). These results indicate that different housing conditions of adult rats evoked significant alterations in D2 and benzodiazepine receptor binding assays, which were modified by ethanol treatment in the case of striatal D2 receptor density.

  19. NLX-112, a novel 5-HT1A receptor agonist for the treatment of L-DOPA-induced dyskinesia: Behavioral and neurochemical profile in rat.

    PubMed

    Iderberg, H; McCreary, A C; Varney, M A; Kleven, M S; Koek, W; Bardin, L; Depoortère, R; Cenci, M A; Newman-Tancredi, A

    2015-09-01

    L-DOPA is the gold-standard treatment for Parkinson's disease (PD), but induces troublesome dyskinesia after prolonged treatment. This is associated with the 'false neurotransmitter' conversion of L-DOPA to dopamine by serotonin neurons projecting from the raphe to the dorsal striatum. Reducing their activity by targeting pre-synaptic 5-HT1A receptors should thus be an attractive therapeutic strategy, but previous 5-HT1A agonists have yielded disappointing results. Here, we describe the activity of a novel, highly selective and potent 5-HT1A agonist, NLX-112 (also known as befiradol or F13640) in rat models relevant to PD and its associated affective disorders. NLX-112 (0.16 mg/kg, i.p.) potently and completely reversed haloperidol-induced catalepsy in intact rats and abolished L-DOPA-induced Abnormal Involuntary Movements (AIMs) in hemiparkinsonian rats, an effect that was reversed by the selective 5-HT1A antagonist, WAY100635. In microdialysis experiments, NLX-112 profoundly decreased striatal 5-HT extracellular levels, indicative of inhibition of serotonergic function. NLX-112 also blunted the L-DOPA-induced surge in dopamine levels on the lesioned side of the brain, an action that likely underlies its anti-dyskinetic effects. NLX-112 (0.16 mg/kg, i.p.) robustly induced rotations in hemiparkinsonian rats, suggesting that it has a motor facilitatory effect. Rotations were abolished by WAY100635 and were ipsilateral to the lesioned side, suggesting a predominant stimulation of the dopamine system on the non-lesioned side of the brain. NLX-112 also efficaciously reduced immobility time in the forced swim test (75% reduction at 0.16 mg/kg, i.p.) and eliminated stress-induced ultrasonic vocalization at 0.08 mg/kg, i.p., effects consistent with potential antidepressant- and anxiolytic-like properties. In other tests, NLX-112 (0.01-0.16 mg/kg, i.p.) did not impair the ability of L-DOPA to rescue forepaw akinesia in the cylinder test but decreased rotarod performance

  20. NLX-112, a novel 5-HT1A receptor agonist for the treatment of L-DOPA-induced dyskinesia: Behavioral and neurochemical profile in rat.

    PubMed

    Iderberg, H; McCreary, A C; Varney, M A; Kleven, M S; Koek, W; Bardin, L; Depoortère, R; Cenci, M A; Newman-Tancredi, A

    2015-09-01

    L-DOPA is the gold-standard treatment for Parkinson's disease (PD), but induces troublesome dyskinesia after prolonged treatment. This is associated with the 'false neurotransmitter' conversion of L-DOPA to dopamine by serotonin neurons projecting from the raphe to the dorsal striatum. Reducing their activity by targeting pre-synaptic 5-HT1A receptors should thus be an attractive therapeutic strategy, but previous 5-HT1A agonists have yielded disappointing results. Here, we describe the activity of a novel, highly selective and potent 5-HT1A agonist, NLX-112 (also known as befiradol or F13640) in rat models relevant to PD and its associated affective disorders. NLX-112 (0.16 mg/kg, i.p.) potently and completely reversed haloperidol-induced catalepsy in intact rats and abolished L-DOPA-induced Abnormal Involuntary Movements (AIMs) in hemiparkinsonian rats, an effect that was reversed by the selective 5-HT1A antagonist, WAY100635. In microdialysis experiments, NLX-112 profoundly decreased striatal 5-HT extracellular levels, indicative of inhibition of serotonergic function. NLX-112 also blunted the L-DOPA-induced surge in dopamine levels on the lesioned side of the brain, an action that likely underlies its anti-dyskinetic effects. NLX-112 (0.16 mg/kg, i.p.) robustly induced rotations in hemiparkinsonian rats, suggesting that it has a motor facilitatory effect. Rotations were abolished by WAY100635 and were ipsilateral to the lesioned side, suggesting a predominant stimulation of the dopamine system on the non-lesioned side of the brain. NLX-112 also efficaciously reduced immobility time in the forced swim test (75% reduction at 0.16 mg/kg, i.p.) and eliminated stress-induced ultrasonic vocalization at 0.08 mg/kg, i.p., effects consistent with potential antidepressant- and anxiolytic-like properties. In other tests, NLX-112 (0.01-0.16 mg/kg, i.p.) did not impair the ability of L-DOPA to rescue forepaw akinesia in the cylinder test but decreased rotarod performance

  1. (3H)WB4101 labels the 5-HT1A serotonin receptor subtype in rat brain. Guanine nucleotide and divalent cation sensitivity

    SciTech Connect

    Norman, A.B.; Battaglia, G.; Creese, I.

    1985-12-01

    In the presence of a 30 nM prazosin mask, (/sup 3/H)-2-(2,6-dimethoxyphenoxyethyl) aminomethyl-1,4-benzodioxane ((/sup 3/H)WB4101) can selectively label 5-HT1 serotonin receptors. Serotonin exhibits high affinity (Ki = 2.5 nM) and monophasic competition for (/sup 3/H) WB4101 binding in cerebral cortex. We have found a significant correlation (r = 0.96) between the affinities of a number of serotonergic and nonserotonergic compounds at (/sup 3/H)WB4101-binding sites in the presence of 30 nM prazosin and (/sup 3/H) lysergic acid diethylamide ((/sup 3/H)LSD)-labeled 5-HT1 serotonin receptors in homogenates of rat cerebral cortex. Despite similar pharmacological profiles, distribution studies indicate that, in the presence of 5 mM MgSO4, the Bmax of (/sup 3/H)WB4101 is significantly lower than the Bmax of (/sup 3/H)LSD in various brain regions. WB4101 competition for (/sup 3/H) LSD-labeled 5-HT1 receptors fits best to a computer-derived model assuming two binding sites, with the KH for WB4101 being similar to the KD of (/sup 3/H)WB4101 binding derived from saturation experiments. This suggests that (/sup 3/H)WB4101 labels only one of the subtypes of the 5-HT1 serotonin receptors labeled by (/sup 3/H)LSD. The selective 5-HT1A serotonin receptor antagonist, spiperone, and the selective 5-HT1A agonist, 8-hydroxy-2-(di-n-propylamino) tetraline, exhibit high affinity and monophasic competition for (/sup 3/H)WB4101 but compete for multiple (/sup 3/H)LSD 5-HT1 binding sites. These data indicate that (/sup 3/H)WB4101 selectively labels the 5-HT1A serotonin receptor, whereas (/sup 3/H) LSD appears to label both the 5-HT1A and the 5-HT1B serotonin receptor subtypes. The divalent cations, Mn2+, Mg2+, and Ca2+ were found to markedly increase the affinity and Bmax of (/sup 3/H)WB4101 binding in cerebral cortex. Conversely, the guanine nucleotides guanylylimidodiphosphate and GTP, but not the adenosine nucleotide ATP, markedly reduce the Bmax of (/sup 3/H)WB4101 binding.

  2. Age-Dependent Switch of the Role of Serotonergic 5-HT1A Receptors in Gating Long-Term Potentiation in Rat Visual Cortex In Vivo

    PubMed Central

    Gagolewicz, Peter J.; Dringenberg, Hans C.

    2016-01-01

    The rodent primary visual cortex (V1) is densely innervated by serotonergic axons and previous in vitro work has shown that serotonin (5-HT) can modulate plasticity (e.g., long-term potentiation (LTP)) at V1 synapses. However, little work has examined the effects of 5-HT on LTP under in vivo conditions. We examined the role of 5-HT on LTP in V1 elicited by theta burst stimulation (TBS) of the lateral geniculate nucleus in urethane-anesthetized (adult and juvenile) rats. Thalamic TBS consistently induced potentiation of field postsynaptic potentials (fPSPs) recorded in V1. While 5-HT application (0.1–10 mM) itself did not alter LTP levels, the broad-acting 5-HT receptor antagonists methiothepin (1 mM) resulted in a clear facilitation of LTP in adult animals, an effect that was mimicked by the selective 5-HT1A receptor antagonist WAY 100635 (1 mM). Interestingly, in juvenile rats, WAY 100635 application inhibited LTP, indicative of an age-dependent switch in the role of 5-HT1A receptors in gating V1 plasticity. Analyses of spontaneous electrocorticographic (ECoG) activity in V1 indicated that the antagonist-induced LTP enhancement was not related to systematic changes in oscillatory activity in V1. Together, these data suggest a facilitating role of 5-HT1A receptor activation on LTP in the juvenile V1, which switches to a tonic, inhibitory influence in adulthood. PMID:27247804

  3. Activation of GABAA or 5HT1A receptors in the raphé pallidus abolish the cardiovascular responses to exogenous stress in conscious rats.

    PubMed

    Pham-Le, Nhut Minh; Cockburn, Chelsea; Nowell, Katherine; Brown, Justin

    2011-11-25

    Dysfunction in serotonin (5HT) neurotransmission in the brainstem of infants may disrupt protective responses to stress and increase the risk for Sudden Infant Death Syndrome (SIDS). The raphé pallidus (NRP) and other brainstem nuclei are rich in 5HT and are thought to mediate stress responses, including increases in blood pressure (BP) and heart rate (HR). Determining how 5HT neurotransmission in the brainstem mediates responses to stress will help to explain how dysfunction in neurotransmission could increase the risk of SIDS. It was hypothesized that alterations in neurotransmission in the NRP, specifically activation of the 5HT(1A) receptor subtype, would block cardiovascular responses to various types of exogenous stress. Using aseptic techniques, male Sprague-Dawley rats were instrumented with radiotelemetry probes which enabled non-invasive measurement of BP and HR. An indwelling microinjection cannula was also stereotaxically implanted into the NRP for injection of drugs that altered local 5HT neurotransmission. Following a one week recovery period, rats were microinjected with either muscimol (GABA(A) receptor agonist), 8-OH-DPAT (agonist to the inhibitory 5HT(1A) receptor), or a vehicle control (artificial cerebral spinal fluid; ACSF) immediately prior to exposure to one of three stressors: handling, air jet, or restraint. Physical handling and restraint of the animal were designed to elicit a mild and a maximal stress response respectively; while an air jet directed at the rat's face was used to provoke a psychological stress that did not require physical contact. All three stressors elicited similar and significant elevations in HR and BP following ACSF that persisted for at least 15 min with BP and HR elevated by ∼14.0 mmHg and ∼56.3 bpm respectively. The similarity in the stress responses suggest even mild handling of a rat elicits a maximal sympathoexcitatory response. The stress response was abolished following 8-OH-DPAT or muscimol

  4. Facilitating antidepressant-like actions of estrogens are mediated by 5-HT1A and estrogen receptors in the rat forced swimming test.

    PubMed

    Estrada-Camarena, E; López-Rubalcava, C; Fernández-Guasti, A

    2006-09-01

    Previous studies have shown that 17beta-estradiol (E2) induces antidepressant-like actions per se and potentiates those produced by fluoxetine (FLX) in the forced swimming test (FST). The aim of the present work was to explore the participation of serotonin 1A receptors (5-HT1A) and estrogen receptors (ERs) in the antidepressant-like actions of E2, FLX or their combination in the FST. Although all antidepressants reduce behavioral immobility, antidepressants that modulate serotonergic neurotransmission increase swimming behavior whereas those that modulate the catecholaminergic neurotransmission increase climbing behavior. Thus, using this animal model, it is possible to infer which neurotransmitter system is modulating the action of an antidepressant compound. Ovariectomized female Wistar rats were used in all experiments. In the first experiment, an effective dose of E2 (10 microg/rat, -48 h) was combined with several doses (0.5, 1.0 and 2 mg/kg) of RU 58668 (a pure ER antagonist) 48 h previous to the FST. The second experiment evaluated the action of (1 mg/kg, -48 h or -23, -5 and -1 h) WAY 100635 (5-HT1A receptor antagonist) on the antidepressant-like action of FLX (10 mg/kg, -23, -5 and -1 h). In the third experiment, the effect of RU 58668 (2 mg/kg, -48) or WAY 100635 (1 mg/kg, -48 h) on the antidepressant-like action of the combination of a sub-optimal dose of E2 (2.5 microg/rat, -48 h) plus a non-effective dose of FLX (2.5 mg/kg, -23,-5 and -1 h) was evaluated. The results showed that RU 58668, the antagonist to the ER, canceled the antidepressant-like action of E2 in a dose-dependent manner. The antagonist to the 5-HT1A receptor blocked the antidepressant action of FLX only when administered simultaneously with FLX, i.e. -23, -5 and -1 h before the FST. Finally, the administration of both RU 58668, and WAY100635 canceled the antidepressant-like action of the combination of E2/FLX. These results imply that both 5-HT1A receptors and ERs participate in the

  5. Women with Multiple Chemical Sensitivity Have Increased Harm Avoidance and Reduced 5-HT1A Receptor Binding Potential in the Anterior Cingulate and Amygdala

    PubMed Central

    Åhs, Fredrik; Savic, Ivanka

    2013-01-01

    Multiple chemical sensitivity (MCS) is a common condition, characterized by somatic distress upon exposure to odors. As in other idiopathic environmental intolerances, the underlying mechanisms are unknown. Contrary to the expectations it was recently found that persons with MCS activate the odor-processing brain regions less than controls, while their activation of the anterior cingulate cortex (ACC) is increased. The present follow-up study was designed to test the hypotheses that MCS subjects have increased harm avoidance and deviations in the serotonin system, which could render them intolerant to environmental odors. Twelve MCS and 11 control subjects, age 22–44, all working or studying females, were included in a PET study where 5-HT1A receptor binding potential (BP) was assessed after bolus injection of [11C]WAY100635. Psychological profiles were assessed by the Temperament and Character Inventory and the Swedish universities Scales of Personality. All MCS and 12 control subjects were also tested for emotional startle modulation in an acoustic startle test. MCS subjects exhibited significantly increased harm avoidance, and anxiety compared to controls. They also had a reduced 5-HT1A receptor BP in amygdala (p = 0.029), ACC (p = 0.005) (planned comparisons, significance level 0.05), and insular cortex (p = 0.003; significance level p<0.005 with Bonferroni correction), and showed an inverse correlation between degree of anxiety and the BP in the amygdala (planned comparison). No group by emotional category difference was found in the startle test. Increased harm avoidance and the observed changes in the 5-HT1A receptor BP in the regions processing harm avoidance provides a plausible pathophysiological ground for the symptoms described in MCS, and yields valuable information for our general understanding of idiopathic environmental intolerances. PMID:23349968

  6. Differential modulation of feline defensive rage behavior in the medial hypothalamus by 5-HT1A and 5-HT2 receptors.

    PubMed

    Hassanain, M; Bhatt, S; Siegel, A

    2003-08-15

    Previous studies have established that the expression of defensive rage behavior in the cat is mediated over reciprocal pathways that link the medial hypothalamus and the dorsolateral quadrant of the midbrain periaqueductal gray matter (PAG). The present study was designed to determine the roles played by 5-HT(1A) and 5-HT(2C) receptors in the medial hypothalamus on the expression of defensive rage behavior elicited from electrical stimulation of the PAG. Monopolar stimulating electrodes were placed in the midbrain PAG from which defensive rage behavior could be elicited by electrical stimulation. During the course of this study, defensive rage was determined by measuring the latency of the "hissing" component of this behavior. Cannula-electrodes were implanted into sites within the medial hypothalamus from which defensive rage behavior could also be elicited by electrical stimulation in order that serotonergic compounds could be microinjected into behaviorally identifiable regions of the hypothalamus at a later time. Microinjections of the 5-HT(1A) receptor agonist 8-OHDPAT (0.1, 1.0 and 3.0 nmol) into the medial hypothalamus suppressed PAG-elicited hissing in a dose-dependent manner. Administration of the 5-HT(1A) antagonist p-MPPI (3.0 nmol) blocked the suppressive effects of 8-OHDPAT upon hissing. The suppressive effects of 8-OHDPAT were specific to defensive rage behavior because this drug (3 nmol) facilitated quiet biting attack. Microinjections of the 5-HT(2C) receptor agonist (+/-)-DOI hydrochloride into the medial hypothalamus (0.5, 1.0, and 3.0 nmol) facilitated the occurrence of PAG-elicited hissing in a dose-dependent manner. In turn, these facilitating effects were blocked by pretreatment with the selective 5-HT(2) antagonist, LY-53,857, which was microinjected into the same medial hypothalamic site. The findings of this study provide evidence that activation of 5-HT(1A) and 5-HT(2) receptors within the medial hypothalamus exert differential modulatory

  7. Differential modulation of feline defensive rage behavior in the medial hypothalamus by 5-HT1A and 5-HT2 receptors.

    PubMed

    Hassanain, M; Bhatt, S; Siegel, A

    2003-08-15

    Previous studies have established that the expression of defensive rage behavior in the cat is mediated over reciprocal pathways that link the medial hypothalamus and the dorsolateral quadrant of the midbrain periaqueductal gray matter (PAG). The present study was designed to determine the roles played by 5-HT(1A) and 5-HT(2C) receptors in the medial hypothalamus on the expression of defensive rage behavior elicited from electrical stimulation of the PAG. Monopolar stimulating electrodes were placed in the midbrain PAG from which defensive rage behavior could be elicited by electrical stimulation. During the course of this study, defensive rage was determined by measuring the latency of the "hissing" component of this behavior. Cannula-electrodes were implanted into sites within the medial hypothalamus from which defensive rage behavior could also be elicited by electrical stimulation in order that serotonergic compounds could be microinjected into behaviorally identifiable regions of the hypothalamus at a later time. Microinjections of the 5-HT(1A) receptor agonist 8-OHDPAT (0.1, 1.0 and 3.0 nmol) into the medial hypothalamus suppressed PAG-elicited hissing in a dose-dependent manner. Administration of the 5-HT(1A) antagonist p-MPPI (3.0 nmol) blocked the suppressive effects of 8-OHDPAT upon hissing. The suppressive effects of 8-OHDPAT were specific to defensive rage behavior because this drug (3 nmol) facilitated quiet biting attack. Microinjections of the 5-HT(2C) receptor agonist (+/-)-DOI hydrochloride into the medial hypothalamus (0.5, 1.0, and 3.0 nmol) facilitated the occurrence of PAG-elicited hissing in a dose-dependent manner. In turn, these facilitating effects were blocked by pretreatment with the selective 5-HT(2) antagonist, LY-53,857, which was microinjected into the same medial hypothalamic site. The findings of this study provide evidence that activation of 5-HT(1A) and 5-HT(2) receptors within the medial hypothalamus exert differential modulatory

  8. Heterogeneous distribution of the serotonin 5-HT(1A) receptor mRNA in chemically identified neurons of the mouse rostral brainstem: Implications for the role of serotonin in the regulation of wakefulness and REM sleep.

    PubMed

    Bonnavion, Patricia; Bernard, Jean-François; Hamon, Michel; Adrien, Joëlle; Fabre, Veronique

    2010-07-15

    The 5-HT(1A) receptor (5-HT(1A)R) plays a key role in the inhibitory influence of serotonin (5-HT) on rapid eye movement (REM) sleep in rodents. However, the neuronal networks mediating such influence are mostly unknown, notably in the mouse. This led us to map 5-HT(1A)R mRNA, by in situ hybridization histochemistry (ISHH), and to characterize the neuronal phenotype of 5-HT(1A)R mRNA-positive neurons by dual ISHH and ISHH combined with immunohistochemistry, throughout the mouse rostral brainstem, a pivotal region for the generation of REM sleep and cortical activation. 5-HT(1A)R mRNA was found in most 5-HT neurons in the dorsal raphe (DR), the median raphe (MnR), the B9, and the interpeduncular (IP) nuclei. 5-HT(1A)R mRNA-positive neurons were also identified in individualized clusters of gamma-aminobutyric acid (GABA)ergic neurons in the DR and in neurons of an undetermined phenotype in the MnR. In addition, 1) GABAergic neurons of the ventral portion of Gudden's dorsal tegmental nucleus (DTg), the IP, and the caudal portion of the deep mesencephalic nucleus (DpMe), and 2) glutamatergic neurons scattered in the caudal pontine reticular nucleus (PnC) and densely packed in the internal lateral parabrachial subnucleus (PBil) also expressed 5-HT(1A)R mRNA. In contrast, no specific 5-HT(1A)R-related ISHH signal was generally detected in brainstem cholinergic and catecholaminergic neurons. These results emphasize the role of 5-HT(1A)R as an autoreceptor and the phenotypical heterogeneity of 5-HT(1A)R-expressing neurons within the DR and the MnR in the mouse brain. They also provide a neuroanatomical basis for understanding the influence of 5-HT(1A)R on REM sleep and wakefulness.

  9. Prophylactic effects of asiaticoside-based standardized extract of Centella asiatica (L.) Urban leaves on experimental migraine: Involvement of 5HT1A/1B receptors.

    PubMed

    Bobade, Vijeta; Bodhankar, Subhash L; Aswar, Urmila; Vishwaraman, Mohan; Thakurdesai, Prasad

    2015-04-01

    The present study aimed at evaluation of prophylactic efficacy and possible mechanisms of asiaticoside (AS) based standardized extract of Centella asiatica (L.) Urban leaves (INDCA) in animal models of migraine. The effects of oral and intranasal (i.n.) pretreatment of INDCA (acute and 7-days subacute) were evaluated against nitroglycerine (NTG, 10 mg·kg(-1), i.p.) and bradykinin (BK, 10 μg, intra-arterial) induced hyperalgesia in rats. Tail flick latencies (from 0 to 240 min) post-NTG treatment and the number of vocalizations post-BK treatment were recorded as a measure of hyperalgesia. Separate groups of rats for negative (Normal) and positive (sumatriptan, 42 mg·kg(-1), s.c.) controls were included. The interaction of INDCA with selective 5-HT1A, 5-HT1B, and 5-HT1D receptor antagonists (NAN-190, Isamoltane hemifumarate, and BRL-15572 respectively) against NTG-induced hyperalgesia was also evaluated. Acute and sub-acute pre-treatment of INDCA [10 and 30 mg·kg(-1) (oral) and 100 μg/rat (i.n.) showed significant anti-nociception activity, and reversal of the NTG-induced hyperalgesia and brain 5-HT concentration decline. Oral pre-treatment with INDCA (30 mg·kg(-1), 7 d) showed significant reduction in the number of vocalization. The anti-nociceptive effects of INDCA were blocked by 5-HT1A and 5-HT1B but not 5-HT1D receptor antagonists. In conclusion, INDCA demonstrated promising anti-nociceptive effects in animal models of migraine, probably through 5-HT1A/1B medicated action.

  10. Cooperative regulation of anxiety and panic-related defensive behaviors in the rat periaqueductal grey matter by 5-HT1A and μ-receptors.

    PubMed

    Roncon, Camila M; Biesdorf, Carla; Coimbra, Norberto C; Audi, Elisabeth A; Zangrossi, Hélio; Graeff, Frederico G

    2013-12-01

    Previous results with the elevated T-maze (ETM) test indicate that the antipanic action of serotonin (5-HT) in the dorsal periaqueductal grey (dPAG) depends on the activation endogenous opioid peptides. The aim of the present work was to investigate the interaction between opioid- and serotonin-mediated neurotransmission in the modulation of defensive responses in rats submitted to the ETM. The obtained results showed that intra-dPAG administration of morphine significantly increased escape latency, a panicolytic-like effect that was blocked by pre-treatment with intra-dPAG injection of either naloxone or the 5-HT1A antagonist N-[2-[4-(2-methoxyphenyl)-1 piperazinyl] ethyl] -N- 2- pyridinyl-ciclohexanecarboxamide maleate (WAY-100635). In addition, previous administration of naloxone antagonized both the anti-escape and the anti-avoidance (anxiolytic-like) effect of the 5-HT1A agonist (±)-8-hydroxy-2-(di-n-propylamino)tetralin hydrobromide (8-OH-DPAT), but did not affect the anti-escape effect of the 5-HT2A agonist (±)-2,5-dimethoxy-4-iodoamphetamine hydrochloride (DOI). Moreover, the combination of sub-effective doses of locally administered 5-HT and morphine significantly impaired ETM escape performance. Finally, the µ-antagonist D-PHE-CYS-TYR-D-TRP-ORN-THR-PEN (CTOP) blocked the anti-avoidance as well as the anti-escape effect of 8-OHDPAT, and the association of sub-effective doses of the µ-opioid receptor agonist [D-Ala(2), N-Me-Phe(4), Gly(5)-ol]-enkephalin acetate salt (DAMGO) and of 8-OHDPAT had anti-escape and anti-avoidance effects in the ETM. These results suggest a synergic interaction between the 5-HT1A and the µ-opioid receptor at post-synaptic level on neurons of the dPAG that regulate proximal defense, theoretically related to panic attacks.

  11. 5-HT1A receptor gene silencers Freud-1 and Freud-2 are differently expressed in the brain of rats with genetically determined high level of fear-induced aggression or its absence.

    PubMed

    Kondaurova, Elena M; Ilchibaeva, Tatiana V; Tsybko, Anton S; Kozhemyakina, Rimma V; Popova, Nina K; Naumenko, Vladimir S

    2016-09-01

    Serotonin 5-HT1A receptor is known to play a crucial role in the mechanisms of genetically defined aggression. In its turn, 5-HT1A receptor functional state is under control of multiple factors. Among others, transcriptional factors Freud-1 and Freud-2 are known to be involved in the repression of 5-HT1A receptor gene expression. However, implication of these factors in the regulation of behavior is unclear. Here, we investigated the expression of 5-HT1A receptor and silencers Freud-1 and Freud-2 in the brain of rats selectively bred for 85 generations for either high level of fear-induced aggression or its absence. It was shown that Freud-1 and Freud-2 levels were different in aggressive and nonaggressive animals. Freud-1 protein level was decreased in the hippocampus, whereas Freud-2 protein level was increased in the frontal cortex of highly aggressive rats. There no differences in 5-HT1A receptor gene expression were found in the brains of highly aggressive and nonaggressive rats. However, 5-HT1A receptor protein level was decreased in the midbrain and increased in the hippocampus of highly aggressive rats. These data showed the involvement of Freud-1 and Freud-2 in the regulation of genetically defined fear-induced aggression. However, these silencers do not affect transcription of the 5-HT1A receptor gene in the investigated rats. Our data indicate the implication of posttranscriptional rather than transcriptional regulation of 5-HT1A receptor functional state in the mechanisms of genetically determined aggressive behavior. On the other hand, the implication of other transcriptional regulators for 5-HT1A receptor gene in the mechanisms of genetically defined aggression could be suggested.

  12. Anxiolytic-like effect of (S)-WAY 100135, a 5-HT1A receptor antagonist, in the murine elevated plus-maze test.

    PubMed

    Rodgers, R J; Cole, J C

    1994-08-22

    The effects of (S)-WAY 100135 ((S)-N-tert-butyl-3-(4-(2-methoxyphenyl)- piperazin-1-yl)-2-phenyl-propanamide dihydrochloride; 2.5-20.0 mg/kg), a 5-HT1A receptor antagonist, on the behaviour of male mice were examined in the elevated plus-maze test of anxiety. An ethological scoring technique was used to provide a comprehensive profile of drug action. Only minor changes in behaviour were observed at 2.5 and 5.0 mg/kg, and consisted of reductions in some (though not all) risk assessment measures. At 10 mg/kg, the compound increased percent open arm entries and percent open arm time, without altering general activity levels. This classic anxiolytic-like profile was confirmed by major reductions in risk assessment measures including protected head-dips and protected stretched attend postures. Although many of the same changes were also observed at 20 mg/kg, the absence of an effect on percent open arm time and a tendency towards increased non-exploratory behaviour suggested (1) some loss of anxiolytic activity and (2) a possible contribution of non-specific factors at higher doses. Present findings indicate that (S)-WAY 100135 produces clear anxiolytic-like effects in the murine elevated plus-maze, a profile that can be distinguished from that produced by 5-HT1A receptor partial agonists in the same test.

  13. Stimulation of hippocampal 5-HT1A receptors causes amnesia and anxiolytic-like but not antidepressant-like effects in the rat.

    PubMed

    Carli, M; Tatarczynska, E; Cervo, L; Samanin, R

    1993-04-01

    Administration of 2 and 5 but not 0.4 microgram/microliter 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) into the CA1 region of the dorsal hippocampus 10 min before the acquisition trial in a passive avoidance task significantly reduced retention latencies 24 h later. The effect of 5 micrograms 8-OH-DPAT on retention latencies was completely antagonized by 1 microgram/microliter spiroxatrine, a 5-HT1A receptor antagonist, infused into the dorsal hippocampus 5 min before 8-OH-DPAT. Administered 5 min after the acquisition trial, 5 micrograms/microliters 8-OH-DPAT had no effect on retention latencies 24 h later. Administration of 5 micrograms/microliters 8-OH-DPAT into the dorsal hippocampus did not significantly change the thresholds for responses to the same electrical stimuli used in the passive avoidance task and had no antidepressant-like effect in the forced swimming test. The dose of 5 micrograms/microliters 8-OH-DPAT administered into the dorsal hippocampus caused anxiolytic-like effects assessed by stress-induced deficit in open field locomotor activity. The results suggest that stimulation of 5-HT1A receptors in the dorsal hippocampus impairs rats' performance in a passive avoidance task by interfering with memory processes or by attenuating the emotional impact of the shock through an anxiolytic action.

  14. Distinct effect of 5-HT1A and 5-HT2A receptors in the medial nucleus of the amygdala on tonic immobility behavior.

    PubMed

    de Paula, Bruna Balbino; Leite-Panissi, Christie Ramos Andrade

    2016-07-15

    The tonic immobility (TI) response is an innate fear behavior associated with intensely dangerous situations, exhibited by many species of invertebrate and vertebrate animals. In humans, it is possible that TI predicts the severity of posttraumatic stress disorder symptoms. This behavioral response is initiated and sustained by the stimulation of various groups of neurons distributed in the telencephalon, diencephalon and brainstem. Previous research has found the highest Fos-IR in the posteroventral part of the medial nucleus of the amygdala (MEA) during TI behavior; however, the neurotransmission of this amygdaloid region involved in the modulation of this innate fear behavior still needs to be clarified. Considering that a major drug class used for the treatment of psychopathology is based on serotonin (5-HT) neurotransmission, we investigated the effects of serotonergic receptor activation in the MEA on the duration of TI. The results indicate that the activation of the 5HT1A receptors or the blocking of the 5HT2 receptors of the MEA can promote a reduction in fear and/or anxiety, consequently decreasing TI duration in guinea pigs. In contrast, blocking the 5HT1A receptors or activating the 5HT2 receptors in this amygdalar region increased the TI duration, suggesting an increase in fear and/or anxiety. These alterations do not appear to be due to a modification of spontaneous motor activity, which might non-specifically affect TI duration. Thus, these results suggest a distinct role of the 5HT receptors in the MEA in innate fear modulation. PMID:27150816

  15. The role of 5-HT1A and 5-HT1B receptors in antidepressant drug actions in the mouse forced swimming test.

    PubMed

    Redrobe, J P; MacSweeney, C P; Bourin, M

    1996-12-30

    The forced swimming test is a behavioural model developed to predict the efficacy of antidepressant drugs. Few studies have been aimed at evaluating the mechanism of action of antidepressants in the forced swimming test. The present study was designed in order to further evaluate the mode of action of antidepressants in the forced swimming test, by using selective agonists and antagonists at 5-HT1A and 5-HT1B receptor sites. Agonists/antagonists and antidepressants were administered 45 min and 30 min, respectively, prior to testing. Prior administration of 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) (1 mg/kg, i.p.) induced anti-immobility effects with the tricyclic antidepressant imipramine (8 mg/kg, i.p.) and noradrenaline uptake inhibitors maprotiline (8 mg/kg, i.p.) and desipramine (16 mg/kg, i.p.), but not with fluoxetine (16 mg/kg, i.p.), citalopram (16 mg/kg, i.p.) or fluvoxamine (8 mg/kg, i.p.). These effects were antagonised by prior administration of 1-(2-methoxyphenyl)-4-[-(2-phthalimido)butyl]piperazine) (NAN 190) (0.5 mg/kg, i.p.). On the other hand, pretreatment with (+/-)-pindolol (32 mg/kg, i.p.) potentiated the effects of the selective serotonin reuptake inhibitors and was devoid of any activity with imipramine (8 mg/kg, i.p.), maprotiline (8 mg/kg, i.p.) or desipramine (16 mg/kg, i.p.). Prior administration of 5-methoxy-3-(1,2,3,6-tetrahydro-4-pyridyl)-1H-indole (RU 24969) enhanced the antidepressant-like effects of the selective serotonin reuptake inhibitors and imipramine (8 mg/kg, i.p.) in the forced swimming test. The anti-immobility effects of the selective serotonin reuptake inhibitors in the forced swimming test seem to be mediated by presynaptic 5-HT1A receptors as well as postsynaptic 5-HT1B receptors. Antidepressant-like effects of the noradrenaline uptake inhibitors seem, on the other hand, to be mediated by postsynaptic 5-HT1A receptors. Considering the variety of 5-HT receptors, it is possible that other subtypes may participate

  16. Effect of dopaminergic D1 receptors on plasticity is dependent of serotoninergic 5-HT1A receptors in L5-pyramidal neurons of the prefrontal cortex.

    PubMed

    Meunier, Claire Nicole Jeanne; Callebert, Jacques; Cancela, José-Manuel; Fossier, Philippe

    2015-01-01

    Major depression and schizophrenia are associated with dysfunctions of serotoninergic and dopaminergic systems mainly in the prefrontal cortex (PFC). Both serotonin and dopamine are known to modulate synaptic plasticity. 5-HT1A receptors (5-HT1ARs) and dopaminergic type D1 receptors are highly represented on dendritic spines of layer 5 pyramidal neurons (L5PyNs) in PFC. How these receptors interact to tune plasticity is poorly understood. Here we show that D1-like receptors (D1Rs) activation requires functional 5HT1ARs to facilitate LTP induction at the expense of LTD. Using 129/Sv and 5-HT1AR-KO mice, we recorded post-synaptic currents evoked by electrical stimulation in layer 2/3 after activation or inhibition of D1Rs. High frequency stimulation resulted in the induction of LTP, LTD or no plasticity. The D1 agonist markedly enhanced the NMDA current in 129/Sv mice and the percentage of L5PyNs displaying LTP was enhanced whereas LTD was reduced. In 5-HT1AR-KO mice, the D1 agonist failed to increase the NMDA current and orientated the plasticity towards L5PyNs displaying LTD, thus revealing a prominent role of 5-HT1ARs in dopamine-induced modulation of plasticity. Our data suggest that in pathological situation where 5-HT1ARs expression varies, dopaminergic treatment used for its ability to increase LTP could turn to be less and less effective. PMID:25775449

  17. Effect of Dopaminergic D1 Receptors on Plasticity Is Dependent of Serotoninergic 5-HT1A Receptors in L5-Pyramidal Neurons of the Prefrontal Cortex

    PubMed Central

    Meunier, Claire Nicole Jeanne; Callebert, Jacques; Cancela, José-Manuel; Fossier, Philippe

    2015-01-01

    Major depression and schizophrenia are associated with dysfunctions of serotoninergic and dopaminergic systems mainly in the prefrontal cortex (PFC). Both serotonin and dopamine are known to modulate synaptic plasticity. 5-HT1A receptors (5-HT1ARs) and dopaminergic type D1 receptors are highly represented on dendritic spines of layer 5 pyramidal neurons (L5PyNs) in PFC. How these receptors interact to tune plasticity is poorly understood. Here we show that D1-like receptors (D1Rs) activation requires functional 5HT1ARs to facilitate LTP induction at the expense of LTD. Using 129/Sv and 5-HT1AR-KO mice, we recorded post-synaptic currents evoked by electrical stimulation in layer 2/3 after activation or inhibition of D1Rs. High frequency stimulation resulted in the induction of LTP, LTD or no plasticity. The D1 agonist markedly enhanced the NMDA current in 129/Sv mice and the percentage of L5PyNs displaying LTP was enhanced whereas LTD was reduced. In 5-HT1AR-KO mice, the D1 agonist failed to increase the NMDA current and orientated the plasticity towards L5PyNs displaying LTD, thus revealing a prominent role of 5-HT1ARs in dopamine-induced modulation of plasticity. Our data suggest that in pathological situation where 5-HT1ARs expression varies, dopaminergic treatment used for its ability to increase LTP could turn to be less and less effective. PMID:25775449

  18. Third Trimester Equivalent Alcohol Exposure Reduces Modulation of Glutamatergic Synaptic Transmission by 5-HT1A Receptors in the Rat Hippocampal CA3 Region.

    PubMed

    Morton, Russell A; Valenzuela, C Fernando

    2016-01-01

    Fetal alcohol exposure has been associated with many neuropsychiatric disorders that have been linked to altered serotonin (5-hydroxytryptamine; 5-HT) signaling, including depression and anxiety. During the first 2 weeks of postnatal life in rodents (equivalent to the third trimester of human pregnancy) 5-HT neurons undergo significant functional maturation and their axons reach target regions in the forebrain (e.g., cortex and hippocampus). The objective of this study was to identify the effects of third trimester ethanol (EtOH) exposure on hippocampal 5-HT signaling. Using EtOH vapor inhalation chambers, we exposed rat pups to EtOH for 4 h/day from postnatal day (P) 2 to P12. The average serum EtOH concentration in the pups was 0.13 ± 0.04 g/dl (legal intoxication limit in humans = 0.08 g/dl). We used brain slices to assess the modulatory actions of 5-HT on field excitatory postsynaptic potentials in the hippocampal CA3 region at P13-P15. Application of the GABAA/glycine receptor antagonist, picrotoxin, caused broadening of field excitatory postsynaptic potentials (fEPSPs), an effect that was reversed by application of 5-HT in slices from air exposed rats. However, this effect of 5-HT was absent in EtOH exposed animals. In slices from naïve animals, application of a 5-HT1A receptor antagonist blocked the effect of 5-HT on the fEPSPs recorded in presence of picrotoxin, suggesting that third trimester ethanol exposure acts by inhibiting the function of these receptors. Studies indicate that 5-HT1A receptors play a critical role in the development of hippocampal circuits. Therefore, inhibition of these receptors by third trimester ethanol exposure could contribute to the pathophysiology of fetal alcohol spectrum disorders. PMID:27375424

  19. Third Trimester Equivalent Alcohol Exposure Reduces Modulation of Glutamatergic Synaptic Transmission by 5-HT1A Receptors in the Rat Hippocampal CA3 Region

    PubMed Central

    Morton, Russell A.; Valenzuela, C. Fernando

    2016-01-01

    Fetal alcohol exposure has been associated with many neuropsychiatric disorders that have been linked to altered serotonin (5-hydroxytryptamine; 5-HT) signaling, including depression and anxiety. During the first 2 weeks of postnatal life in rodents (equivalent to the third trimester of human pregnancy) 5-HT neurons undergo significant functional maturation and their axons reach target regions in the forebrain (e.g., cortex and hippocampus). The objective of this study was to identify the effects of third trimester ethanol (EtOH) exposure on hippocampal 5-HT signaling. Using EtOH vapor inhalation chambers, we exposed rat pups to EtOH for 4 h/day from postnatal day (P) 2 to P12. The average serum EtOH concentration in the pups was 0.13 ± 0.04 g/dl (legal intoxication limit in humans = 0.08 g/dl). We used brain slices to assess the modulatory actions of 5-HT on field excitatory postsynaptic potentials in the hippocampal CA3 region at P13-P15. Application of the GABAA/glycine receptor antagonist, picrotoxin, caused broadening of field excitatory postsynaptic potentials (fEPSPs), an effect that was reversed by application of 5-HT in slices from air exposed rats. However, this effect of 5-HT was absent in EtOH exposed animals. In slices from naïve animals, application of a 5-HT1A receptor antagonist blocked the effect of 5-HT on the fEPSPs recorded in presence of picrotoxin, suggesting that third trimester ethanol exposure acts by inhibiting the function of these receptors. Studies indicate that 5-HT1A receptors play a critical role in the development of hippocampal circuits. Therefore, inhibition of these receptors by third trimester ethanol exposure could contribute to the pathophysiology of fetal alcohol spectrum disorders. PMID:27375424

  20. Involvement of 5-HT1A Receptors in the Anxiolytic-Like Effects of Quercitrin and Evidence of the Involvement of the Monoaminergic System

    PubMed Central

    Li, Jian; Liu, Qian-tong; Chen, Yi; Liu, Jie; Shi, Jin-li; Liu, Yong; Guo, Jian-you

    2016-01-01

    Quercitrin is a well-known flavonoid that is contained in Flos Albiziae, which has been used for the treatment of anxiety. The present study investigated the anxiolytic-like effects of quercitrin in experimental models of anxiety. Compared with the control group, repeated treatment with quercitrin (5.0 and 10.0 mg/kg/day, p.o.) for seven days significantly increased the percentage of entries into and time spent on the open arms of the elevated plus maze. In the light/dark box test, quercitrin exerted an anxiolytic-like effect at 5 and 10 mg/kg. In the marble-burying test, quercitrin (5.0 and 10.0 mg/kg) also exerted an anxiolytic-like effect. Furthermore, quercitrin did not affect spontaneous locomotor activity. The anxiolytic-like effects of quercitrin in the elevated plus maze and light/dark box test were blocked by the serotonin-1A (5-hydroxytryptamine-1A (5-HT1A)) receptor antagonist WAY-100635 (3.0 mg/kg, i.p.) but not by the γ-aminobutyric acid-A (GABAA) receptor antagonist flumazenil (0.5 mg/kg, i.p.). The levels of brain monoamines (5-HT and dopamine) and their metabolites (5-hydroxy-3-indoleacetic acid, 3,4-dihydroxyphenylacetic acid, and homovanillic acid) were decreased after quercitrin treatment. These data suggest that the anxiolytic-like effects of quercitrin might be mediated by 5-HT1A receptors but not by benzodiazepine site of GABAA receptors. The results of the neurochemical studies suggest that these effects are mediated by modulation of the levels of monoamine neurotransmitters. PMID:27298626

  1. An Orally Active Phenylaminotetralin-Chemotype Serotonin 5-HT7 and 5-HT1A Receptor Partial Agonist that Corrects Motor Stereotypy in Mouse Models.

    PubMed

    Canal, Clinton E; Felsing, Daniel E; Liu, Yue; Zhu, Wanying; Wood, JodiAnne T; Perry, Charles K; Vemula, Rajender; Booth, Raymond G

    2015-07-15

    Stereotypy (e.g., repetitive hand waving) is a key phenotype of autism spectrum disorder, Fragile X and Rett syndromes, and other neuropsychiatric disorders, and its severity correlates with cognitive and attention deficits. There are no effective treatments, however, for stereotypy. Perturbation of serotonin (5-HT) neurotransmission contributes to stereotypy, suggesting that distinct 5-HT receptors may be pharmacotherapeutic targets to treat stereotypy and related neuropsychiatric symptoms. For example, preclinical studies indicate that 5-HT7 receptor activation corrects deficits in mouse models of Fragile X and Rett syndromes, and clinical trials for autism are underway with buspirone, a 5-HT1A partial agonist with relevant affinity at 5-HT7 receptors. Herein, we report the synthesis, in vitro molecular pharmacology, behavioral pharmacology, and pharmacokinetic parameters in mice after subcutaneous and oral administration of (+)-5-(2'-fluorophenyl)-N,N-dimethyl-1,2,3,4-tetrahydronaphthalen-2-amine ((+)-5-FPT), a new, dual partial agonist targeting both 5-HT7 (Ki = 5.8 nM, EC50 = 34 nM) and 5-HT1A (Ki = 22 nM, EC50 = 40 nM) receptors. Three unique, heterogeneous mouse models were used to assess the efficacy of (+)-5-FPT to reduce stereotypy: idiopathic jumping in C58/J mice, repetitive body rotations in C57BL/6J mice treated with the NMDA antagonist, MK-801, and repetitive head twitching in C57BL/6J mice treated with the 5-HT2 agonist, DOI. Systemic (+)-5-FPT potently and efficaciously reduced or eliminated stereotypy in each of the mouse models without altering locomotor behavior on its own, and additional tests showed that (+)-5-FPT, at the highest behaviorally active dose tested, enhanced social interaction and did not cause behaviors indicative of serotonin syndrome. These data suggest that (+)-5-FPT is a promising medication for treating stereotypy in psychiatric disorders.

  2. Antidepressant-like activity of Tagetes lucida Cav. is mediated by 5-HT(1A) and 5-HT(2A) receptors.

    PubMed

    Bonilla-Jaime, H; Guadarrama-Cruz, G; Alarcon-Aguilar, F J; Limón-Morales, O; Vazquez-Palacios, G

    2015-10-01

    It has been demonstrated that the aqueous extract of Tagetes lucida Cav. shows an antidepressant-like effect on the forced swimming test (FST) in rats. The aim of this study was to analyze the participation of the serotoninergic system in the antidepressant-like effect of the aqueous extract of T. lucida. Different doses of the extract of T. lucida were administered at 72, 48, 24, 18 and 1 h before FST. The animals were pretreated with a 5-HT1A receptor antagonist (WAY-100635, 0.5 mg/kg), a 5-HT2A receptor antagonist (ketanserin, 5 mg/kg), a β-noradrenergic receptor antagonist (propranolol, 200 mg/kg), and with a α2-noradrenergic receptor antagonist (yohimbine, 1 mg/kg) alone or combined with the extract and pretreated with a serotonin synthesis inhibitor (PCPA) before treatment with 8-OH-DPAT + the extract of T. lucida. In addition, suboptimal doses of the 5-HT1A agonist (8-OH-DPAT) + non-effective dose of extract was analyzed in the FST. To determine the presence of flavonoids, the aqueous extract of T. lucida (20 µl, 4 mg/ml) was injected in HPLC; however, a quercetin concentration of 7.72 mg/g of extract weight was detected. A suboptimal dose of 8-OH-DPAT + extract of T. lucida decreased immobility and increased swimming and climbing. An antidepressant-like effect with the aqueous extract of T. lucida at doses of 100 and 200 mg/kg was observed on the FST with decreased immobility behavior and increased swimming; however, this effect was blocked by WAY-100635, ketanserin and PCPA but not by yohimbine and propranolol, suggesting that the extract of T. lucida could be modulating the release/reuptake of serotonin.

  3. Differential effects of the 5-hydroxytryptamine (5-HT)1A receptor inverse agonists Rec 27/0224 and Rec 27/0074 on electrophysiological responses to 5-HT1A receptor activation in rat dorsal raphe nucleus and hippocampus in vitro.

    PubMed

    Corradetti, Renato; Mlinar, Boris; Falsini, Chiara; Pugliese, Anna Maria; Cilia, Antonio; Destefani, Carla; Testa, Rodolfo

    2005-10-01

    The pharmacological properties of cyclohexanecarboxylic acid, {2-[4-(2-bromo-5-methoxybenzyl)piperazin-1-yl]ethyl}-(2-trifluoromethoxyphenyl)amide (Rec 27/0224), and cyclohexanecarboxylic acid, (2-methoxy-phenyl)-{2-[4-(2-methoxyphenyl)-piperazin-1-yl]ethyl}amide (Rec 27/0074), were characterized using radioligand displacement and guanosine 5'-O-(3-[35S]thiotriphosphate) ([35S]GTPgammaS) binding assays, as well as electrophysiological experiments, in rat hippocampal and dorsal raphe nucleus (DRN) slices. Both compounds showed a high affinity (Ki, approximately 1 nM) and selectivity (>70-fold) at human 5-hydroxytryptamine (5-HT)1A receptors versus other 5-HT receptors. In [35S]GTPgammaS binding assays on HeLa cells stably expressing human 5-HT1A receptors, Rec 27/0224 and Rec 27/0074 inhibited basal [35S]GTPgammaS binding by 44.8 +/- 1.7% (pEC50 = 8.58) and 25 +/- 2.5% (pEC50 = 8.86), respectively. In intracellularly recorded CA1 pyramidal cells, 5-HT1A (hetero)receptor-mediated hyperpolarization, elicited by 100 nM 5-carboxamidoytryptamine (5-CT), was partially antagonized by Rec 27/0224 (approximately 50%; IC50 = 18.0 nM) and Rec 27/0074 (74%; IC50 = 0.8 nM). In extracellularly recorded DRN serotonergic neurons, Rec 27/0224 and Rec 27/0074 fully antagonized the inhibition of firing caused by the activation of 5-HT1A (auto)receptors by 30 nM 5-CT with an IC50 of 34.9 nM and 16.5 nM, respectively. The antagonism had a slow time course, reaching a steady state within 60 min. Both compounds also antagonized the citalopram-elicited, endogenous 5-HT-mediated inhibition of cell firing. In conclusion, Rec 27/0224 and Rec 27/0074 exhibited inverse agonism in [35S]GTPgammaS binding assays and differential antagonistic properties on 5-HT1A receptor-mediated responses in the hippocampus but not in the DRN. Whether this differential effect is causally related to inverse agonist activity is unclear. The qualitatively different nature of the antagonism in the hippocampus versus

  4. 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

  5. Expression of the 5-HT1A Serotonin Receptor in the Hippocampus Is Required for Social Stress Resilience and the Antidepressant-Like Effects Induced by the Nicotinic Partial Agonist Cytisine

    PubMed Central

    Mineur, Yann S; Einstein, Emily B; Bentham, Matthew P; Wigestrand, Mattis B; Blakeman, Sam; Newbold, Sylvia A; Picciotto, Marina R

    2015-01-01

    Nicotinic acetylcholine receptor (nAChR) blockers potentiate the effects of selective serotonin reuptake inhibitors (SSRIs) in some treatment-resistant patients; however, it is not known whether these effects are independent, or whether the two neurotransmitter systems act synergistically. We first determined that the SSRI fluoxetine and the nicotinic partial agonist cytisine have synergistic effects in a mouse model of antidepressant efficacy, whereas serotonin depletion blocked the effects of cytisine. Using a pharmacological approach, we found that the 5-HT1A agonist 8-OH-DPAT also potentiated the antidepressant-like effects of cytisine, suggesting that this subtype might mediate the interaction between the serotonergic and cholinergic systems. The 5-HT1A receptors are located both presynaptically and postsynaptically. We therefore knocked down 5-HT1A receptors in either the dorsal raphe (presynaptic autoreceptors) or the hippocampus (a brain area with high expression of 5-HT1A heteroreceptors sensitive to cholinergic effects on affective behaviors). Knockdown of 5-HT1A receptors in hippocampus, but not dorsal raphe, significantly decreased the antidepressant-like effect of cytisine. This study suggests that serotonin signaling through postsynaptic 5-HT1A receptors in the hippocampus is critical for the antidepressant-like effects of a cholinergic drug and begins to elucidate the molecular mechanisms underlying interactions between the serotonergic and cholinergic systems related to mood disorders. PMID:25288485

  6. Expression of the 5-HT1A serotonin receptor in the hippocampus is required for social stress resilience and the antidepressant-like effects induced by the nicotinic partial agonist cytisine.

    PubMed

    Mineur, Yann S; Einstein, Emily B; Bentham, Matthew P; Wigestrand, Mattis B; Blakeman, Sam; Newbold, Sylvia A; Picciotto, Marina R

    2015-03-01

    Nicotinic acetylcholine receptor (nAChR) blockers potentiate the effects of selective serotonin reuptake inhibitors (SSRIs) in some treatment-resistant patients; however, it is not known whether these effects are independent, or whether the two neurotransmitter systems act synergistically. We first determined that the SSRI fluoxetine and the nicotinic partial agonist cytisine have synergistic effects in a mouse model of antidepressant efficacy, whereas serotonin depletion blocked the effects of cytisine. Using a pharmacological approach, we found that the 5-HT1A agonist 8-OH-DPAT also potentiated the antidepressant-like effects of cytisine, suggesting that this subtype might mediate the interaction between the serotonergic and cholinergic systems. The 5-HT1A receptors are located both presynaptically and postsynaptically. We therefore knocked down 5-HT1A receptors in either the dorsal raphe (presynaptic autoreceptors) or the hippocampus (a brain area with high expression of 5-HT1A heteroreceptors sensitive to cholinergic effects on affective behaviors). Knockdown of 5-HT1A receptors in hippocampus, but not dorsal raphe, significantly decreased the antidepressant-like effect of cytisine. This study suggests that serotonin signaling through postsynaptic 5-HT1A receptors in the hippocampus is critical for the antidepressant-like effects of a cholinergic drug and begins to elucidate the molecular mechanisms underlying interactions between the serotonergic and cholinergic systems related to mood disorders.

  7. Cannabidiol inhibits the reward-facilitating effect of morphine: involvement of 5-HT1A receptors in the dorsal raphe nucleus.

    PubMed

    Katsidoni, Vicky; Anagnostou, Ilektra; Panagis, George

    2013-03-01

    Cannabidiol is a non-psychotomimetic constituent of Cannabis sativa, which induces central effects in rodents. It has been shown that cannabidiol attenuates cue-induced reinstatement of heroin seeking. However, to the best of our knowledge, its effects on brain stimulation reward and the reward-facilitating effects of drugs of abuse have not yet been examined. Therefore, we investigated the effects of cannabidiol on brain reward function and on the reward-facilitating effect of morphine and cocaine using the intracranial self-stimulation (ICSS) paradigm. Rats were prepared with a stimulating electrode into the medial forebrain bundle (MFB), and a guide cannula into the dorsal raphe (microinjection experiments), and were trained to respond for electrical brain stimulation. A low dose of cannabidiol did not affect the reinforcing efficacy of brain stimulation, whereas higher doses significantly elevated the threshold frequency required for MFB ICSS. Both cocaine and morphine lowered ICSS thresholds. Cannabidiol inhibited the reward-facilitating effect of morphine, but not cocaine. This effect was reversed by pre-treatment with an intra-dorsal raphe injection of the selective 5-HT1A receptor antagonist WAY-100635. The present findings indicate that cannabidiol does not exhibit reinforcing properties in the ICSS paradigm at any of the doses tested, while it decreases the reward-facilitating effects of morphine. These effects were mediated by activation of 5-HT1A receptors in the dorsal raphe. Our results suggest that cannabidiol interferes with brain reward mechanisms responsible for the expression of the acute reinforcing properties of opioids, thus indicating that cannabidiol may be clinically useful in attenuating the rewarding effects of opioids.

  8. The spleen is required for 5-HT1A receptor agonist-mediated increases in mean circulatory filling pressure during hemorrhagic shock in the rat.

    PubMed

    Tiniakov, Ruslan; Scrogin, Karie E

    2009-05-01

    The 5-HT(1A) receptor agonist, 8- OH-DPAT, increases whole body venous tone (mean circulatory filling pressure; MCFP), and attenuates metabolic acidosis in a rat model of unresuscitated hemorrhagic shock. To determine whether improved acid-base balance was associated with sympathetic activation and venous constriction, MCFP, sympathetic activity (SA), and blood gases were compared in hemorrhaged rats following administration of 5-HT(1A) receptor agonist 8-OH-DPAT, the arterial vasoconstrictor arginine vasopressin (AVP), or saline. To further determine whether protection of acid-base balance was dependent on splenic contraction and blood mobilization, central venous pressure (CVP), MCFP, and blood gases were determined during hemorrhage and subsequent 8-OH-DPAT-administration in rats subjected to real or sham splenectomy. Subjects were hemorrhaged to an arterial pressure of 50 mmHg for 25 min and subsequently were treated with 8-OH-DPAT (30 nmol/kg iv), AVP titrated to match the pressor effect of 8-OH-DPAT (approximately 2 ng/min iv), or infusion of normal saline. 8-OH-DPAT increased MAP, CVP, MCFP, and SA, and decreased lactate accumulation. AVP did not affect CVP or SA, but raised MCFP slightly to a level intermediate between 8-OH-DPAT- and saline-treated rats. Infusion of AVP also produced a modest protection against metabolic acidosis. Splenectomy prevented the rise in CVP, MCFP, and protection against metabolic acidosis produced by 8-OH-DPAT but had no effect on the immediate pressor response to the drug. Together, the data indicate that 8-OH-DPAT produces a pattern of cardiovascular responses consistent with a sympathetic-mediated venoconstriction that is, in part, responsible for the drug's beneficial effect on acid-base balance. Moreover, blood mobilization stimulated by the spleen is required for the beneficial effects of 8-OH-DPAT.

  9. 5-HT1A receptor gene C -1019 G polymorphism and amygdala volume in borderline personality disorder.

    PubMed

    Zetzsche, T; Preuss, U W; Bondy, B; Frodl, T; Zill, P; Schmitt, G; Koutsouleris, N; Rujescu, D; Born, C; Reiser, M; Möller, H-J; Meisenzahl, E M

    2008-04-01

    Alterations of amygdala structure and function have been repeatedly described in patients with borderline personality disorder (BPD). The aim of our study was to determine whether a functional polymorphism of the 5-hydroxytryptamine(1A) receptor (5-HTR(1A)) gene C -1019 G (identity number: rs6295 G/C) is associated with structural changes of the amygdala in patients with BPD. Twenty-five right-handed female inpatients with BPD according to DSM IV and 25 healthy controls matched for age, sex, handedness and educational status were enrolled. Brain volumetry of the amygdala was performed with a 1.5-T Magnetom Vision apparatus (Siemens, Erlangen, Germany) and analyzed by the software program 'BRAINS'. Patients who have the 5-HTR(1A) gene G allele had significantly smaller amygdala volumes than C/C genotype carriers (P = 0.02). While no difference of allelic distribution between patients and controls was detected, the described effect of 5-HTR(1A) genotype on amygdala volume was found for the whole group of patients, as well as in the subgroup of patients with comorbid major depression (P = 0.004) but not in controls. In contrast to these subgroups of BPD patients who had significant amygdala volume differences, the mean amygdala volume of the whole group of BPD patients was not significantly different from that of controls. In summary, our study provides first evidence that 5-HTR(1A) gene C -1019 G polymorphism is associated with structural changes in the limbic system of BPD patients, a finding that might be disease related and might contribute to explanation of previous discrepant results regarding amygdala volume changes in BPD. Future research is recommended to clarify possible interactions between this functional polymorphism and symptoms, course and treatment responses in this disorder.

  10. Central amygdala nicotinic and 5-HT1A receptors mediate the reversal effect of nicotine and MDMA on morphine-induced amnesia.

    PubMed

    Tirgar, F; Rezayof, A; Zarrindast, M-R

    2014-09-26

    The present study was designed to investigate possible involvement of the central amygdala (CeA) nicotinic acetylcholine (nACh) and 5-hydroxytryptamine 1A (5-HT1A) receptors in the reversal effect of nicotine and 3,4-methylenedioxy-N-methylamphetamine (MDMA or ecstasy) on morphine-induced amnesia. Two guide cannulas were stereotaxically implanted in the CeA regions and a step-through passive avoidance task was used for the assessment of memory retrieval in adult male Wistar rats. Our results indicated that post-training s.c. administration of morphine (3-7-mg/kg) impaired memory retrieval. Pre-test administration of nicotine (0.3- and 0.5-mg/kg, s.c.) reversed morphine-induced amnesia. In addition, pre-test intra-CeA injection of MDMA (1-2-μg/rat) with an ineffective dose of nicotine (0.1-mg/kg, s.c.) improved memory retrieval, suggesting the interactive effect of the drugs on memory formation. It should be noted that that pre-test intra-CeA injection of 2-μg/rat of MDMA by itself produced amnesia. Interestingly, pre-test intra-CeA injection of mecamylamine, a nACh receptor antagonist (1-2-μg/rat) or (S)-WAY 100135 (0.25-1-μg/rat), a selective 5-HT1A receptor antagonist inhibited the improvement of morphine-induced amnesia which was produced by pre-test co-injection of nicotine and MDMA. Pre-test intra-CeA injection of the same doses of MDMA, mecamylamine or (S)-WAY 100135 by itself had no effect on morphine-induced amnesia. Moreover, pre-test injection of the same doses of mecamylamine or (S)-WAY 100135 into the CeA alone could not change memory retrieval. Taken together, it can be concluded that there is a functional interaction between morphine, nicotine and MDMA via the CeA nicotinic and serotonergic receptor mechanisms in passive avoidance memory retrieval. Moreover, cross state-dependent memory retrieval may have been induced between the drugs and this probably depends on the rewarding effects of the drugs.

  11. Potentiation of 5-methoxy-N,N-dimethyltryptamine-induced hyperthermia by harmaline and the involvement of activation of 5-HT1A and 5-HT2A receptors.

    PubMed

    Jiang, Xi-Ling; Shen, Hong-Wu; Yu, Ai-Ming

    2015-02-01

    5-Methoxy-N,N-dimethyltryptamine (5-MeO-DMT) and harmaline are serotonin (5-HT) analogs often abused together, which alters thermoregulation that may indicate the severity of serotonin toxicity. Our recent studies have revealed that co-administration of monoamine oxidase inhibitor harmaline leads to greater and prolonged exposure to 5-HT agonist 5-MeO-DMT that might be influenced by cytochrome P450 2D6 (CYP2D6) status. This study was to define the effects of harmaline and 5-MeO-DMT on thermoregulation in wild-type and CYP2D6-humanized (Tg-CYP2D6) mice, as well as the involvement of 5-HT receptors. Animal core body temperatures were monitored noninvasively in the home cages after implantation of telemetry transmitters and administration of drugs. Harmaline (5 and 15 mg/kg, i.p.) alone was shown to induce hypothermia that was significantly affected by CYP2D6 status. In contrast, higher doses of 5-MeO-DMT (10 and 20 mg/kg) alone caused hyperthermia. Co-administration of harmaline (2, 5 or 15 mg/kg) remarkably potentiated the hyperthermia elicited by 5-MeO-DMT (2 or 10 mg/kg), which might be influenced by CYP2D6 status at certain dose combination. Interestingly, harmaline-induced hypothermia was only attenuated by 5-HT1A receptor antagonist WAY-100635, whereas 5-MeO-DMT- and harmaline-5-MeO-DMT-induced hyperthermia could be suppressed by either WAY-100635 or 5-HT2A receptor antagonists (MDL-100907 and ketanserin). Moreover, stress-induced hyperthermia under home cage conditions was not affected by WAY-100635 but surprisingly attenuated by MDL-100907 and ketanserin. Our results indicate that co-administration of monoamine oxidase inhibitor largely potentiates 5-MeO-DMT-induced hyperthermia that involves the activation of both 5-HT1A and 5-HT2A receptors. These findings shall provide insights into development of anxiolytic drugs and new strategies to relieve the lethal hyperthermia in serotonin toxicity.

  12. Pindolol does not act only on 5-HT1A receptors in augmenting antidepressant activity in the mouse forced swimming test.

    PubMed

    Bourin, M; Redrobe, J P; Baker, G B

    1998-04-01

    The present study was undertaken to identify the receptor subtypes involved in (+/-) pindolol's ability to enhance the effects of antidepressant drugs in the mouse forced swimming test. Interaction studies were performed with S 15535 (presynaptic 5-HT1A receptor agonist) and methiothepin (5-HT1B autoreceptor antagonist) in an attempt to attenuate or potentiate antidepressant-like activity. (+/-) Pindolol was tested in combination with selective agonists and antagonists at 5-HT1, 5-HT2 and 5-HT3 receptor subtypes. Pretreatment with S 15535 and methiothepin attenuated the activity of paroxetine, fluvoxamine and citalopram (32 mg/kg, i.p.; P < 0.01). (+/-) Pindolol (32 mg/kg, i.p.) induced significant anti-immobility effects when tested in combination with 5-methoxy-3-(1,2,3,6-tetrahydro-4-pyridyl)-1H-indole (RU 24969) (1 mg/kg, i.p.; P < 0.05), 1-(2-methoxyphenyl)-4-[-(2-phthalimido) butyl]piperazine) (NAN 190) (0.5 mg/kg; P < 0.05) and ondansetron (0.00001 mg/kg, i.p.; P < 0.01). Pretreatment with NAN 190 (0.5 mg/kg, i.p.) potentiated the effects of RU 24969 (1 mg/kg, i.p.; P < 0.05) and (+/-) pindolol (32 mg/kg, i.p.; P < 0.05) in the forced swimming test, as did ondansetron (0.00001 mg/kg, i.p.). Significant additive effects were induced when RU 24969 (1 mg/kg, i.p.) was tested in combination with NAN 190 (0.5 mg/kg, i.p.; P < 0.05), (+/-) pindolol (32 mg/kg, i.p.; P < 0.05) and ondansetron (0.0000 mg/kg, i.p.; P < 0.05). 8-Hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) (1 mg/kg, i.p.) or ketanserin (8 mg/kg, i.p.) did not induce significant antidepressant-like effects with any of the agonists/antagonists tested. The results of the present study suggest that pindolol is acting at presynaptic 5-HT1B serotonergic receptors, in addition to the 5-HT1A subtype, in augmenting the activity of antidepressants in the mouse forced swimming test.

  13. Effects of 5-HT1A receptor agonists and NMDA receptor antagonists in the social interaction test and the elevated plus maze.

    PubMed

    Dunn, R W; Corbett, R; Fielding, S

    1989-10-01

    The effects of several 5-HT1A agonists and excitatory amino acid antagonists were compared to the standard benzodiazepines, diazepam and chlordiazepoxide (CDP) in two assays predictive of anxiolytic activity, the social interaction and elevated plus maze procedures. Indicative of anxiolytic effects the 5-HT1A agonists, buspirone, gepirone and 8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT) all significantly increased social interaction time and open arm exploration time in the social interaction and elevated plus maze procedures, respectively. Likewise, anxiolytic activity in these assays were also produced by the competitive N-methyl-D-aspartate (NMDA) antagonists, 2-amino-5-phosphonovaleric acid (AP-5), 2-amino-7-phosphonoheptanoic acid (AP-7), 3-(2-carboxypiperazin-4-yl)-propyl-1-phosphonic acid (CPP) and the non-competitive NMDA antagonist, (+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine (MK-801) while NMDA produced anxiogenic effects. Furthermore, the anxiolytic effects of these agents were of equal magnitude to the benzodiazepines. These two classes of compounds were differentiated in the yohimbine-induced seizure assay, with the NMDA antagonists dose dependently antagonizing seizures similar to the benzodiazepines while the 5-HT1A agonists were inactive. These results suggest that the 5-HT1A agonists and the NMDA antagonists may be potential non-classical anxiolytic agents with different mechanisms of action.

  14. Contribution of the Striatum to the Effects of 5-HT1A Receptor Stimulation in L-DOPA-treated Hemiparkinsonian Rats

    PubMed Central

    Bishop, Christopher; Krolewski, David M.; Eskow, Karen L.; Barnum, Christopher J.; Dupre, Kristin B.; Deak, Terrence; Walker, Paul D.

    2009-01-01

    Clinical and experimental studies implicate the use of serotonin (5-HT)1A receptor agonists for the reduction of l-3,4-dihydroxyphenylalanine (L-DOPA)-induced dyskinesia (LID). Although raphe nuclei likely play a role in these antidyskinetic effects, an unexplored population of striatal 5-HT1A receptors (5-HT1AR) may also contribute. To better characterize this mechanism, L-DOPA-primed hemiparkinsonian rats received the 5-HT1AR agonist ±8-OH-DPAT (0, 0.1, 1.0 mg/kg, i.p.) with or without cotreatment with the 5-HT1AR antagonist WAY100635 (0.5 mg/kg, i.p.) 5 min after L-DOPA, after which abnormal involuntary movements (AIMs), rotations, and forelimb akinesia were quantified. To establish the effects of 5-HT1AR stimulation on L-DOPA-induced c-fos and preprodynorphin (PPD) mRNA within the dopamine-depleted striatum, immunohistochemistry and real-time reverse transcription polymerase chain reaction, respectively, were used. Finally, to determine the contribution of striatal 5-HT1AR to these effects, L-DOPA-primed hemiparkinsonian rats received bilateral intrastriatal microinfusions of ±8-OH-DPAT (0, 5, or 10 μg/side), WAY100635 (5 μg/side), or both (10 μg + 5 μg/side) 5 min after L-DOPA, after which AIMs and rotations were examined. Systemic ±8-OH-DPAT dose- and receptor-dependently attenuated L-DOPA-mediated AIMs and improved forelimb akinesia. Striatal c-fos immuno-reactivity and PPD mRNA ipsilateral to the lesion were strongly induced by L-DOPA, while ±8-OH-DPAT suppressed these effects. Finally, intrastriatal infusions of ±8-OH-DPAT reduced AIMs while coinfusion of WAY100635 reversed its antidyskinetic effect. Collectively, these results support the hypothesis that the cellular and behavioral properties of 5-HT1AR agonists are conveyed in part via a population of functional 5-HT1AR within the striatum. PMID:19115412

  15. A 5-HT1A-like receptor is involved in the regulation of the embryonic rotation of Lymnaea stagnalis L.

    PubMed

    Hiripi, László; Elekes, Károly

    2010-06-01

    Cilia driven rotation of the pond snail Lymnaea stagnalis embryos is regulated by serotonin (5-HT). In the present study, physiological and biochemical assays were used to identify the 5-HT receptor type involved in rotation. The 5-HTergic agonists applied stimulated the rotation by 180-400% and their rank order potency was as follows: LSD>5-HT>8-OH-DPAT>WB4101>5-CT. The applied antagonists, spiperone, propranalol and mianserin inhibited the 5-HT or 8-OH-DPAT stimulated rotation of the embryos by 50-70%. (3)H-5-HT was bound specifically to the washed pellet of the embryo homogenates. The specific binding of (3)H-5-HT was saturable and showed a single, high affinity binding site with K(d) 7.36 nM and B(max) 221 fmol/mg pellet values. This is the first report demonstrating the high affinity binding of (3)H-5-HT to the native receptor in molluscs. All of the pharmacons that stimulated the rotation or inhibited the 5-HT or 8-OH-DPAT evoked stimulation displaced effectively the binding of (3)H-5-HT. 5-HT resulted in the inhibition of forskolin stimulated cAMP accumulation, showing that 5-HT is negatively coupled to adenylate cyclase. Our results suggest that in the 5-HTergic regulation of the embryonic rotation in L. stagnalis a 5-HT(1A)-like receptor of the vertebrate type is involved.

  16. Effect of mouse chromosome 13 terminal fragment on liability to catalepsy and expression of tryptophane hydroxylase-2, serotonin transporter, and 5-HT1A receptor genes in the brain.

    PubMed

    Kulikov, A V; Naumenko, V S; Bazovkina, D V; Dee, V Yu; Osipova, D V; Popova, N K

    2009-05-01

    Congenic mice obtained by genome fragments transfer from one strain to another are a potent tool for studies of the molecular mechanisms of behavioral mutations. The 59-70 cM fragment of chromosome 13 containing the locus determining predisposition to freezing reaction (catalepsy) and the gene encoding 5-HT(1A) receptor were transferred from cataleptic CBA/Lac mice into the genome of catalepsy-resistant AKR/J mice. The impact of this fragment for the severity of catalepsy and expression of genes encoding tryptophane hydroxylase-2, serotonin transporter, and 5-HT(1A) receptor was studied. Half of mice of the resultant congenic AKR.CBA-D13Mit76 strain exhibited pronounced catalepsy, similarly to donor CBA animals. The expression of 5-HT(1A) receptor gene in the midbrain of AKR animals was significantly higher than in CBA. The level of 5-HT(1A) receptor mRNA in AKR.CBA-D13Mit76 animals was significantly higher than in the donor strain. Mice of parental AKR and CBA strains did not differ from each other and from AKR.CBA-D13Mit76 animals by the levels of tryptophane hydroxylase-2 and serotonin transporter genes mRNA. These data prove the location of catalepsy regulating gene in the distal fragment of chromosome 13. The recipient strain genome enhanced the expression of 5-HT(1A) receptor gene in the brain without modulating the expression of catalepsy gene.

  17. Decreased expression of Freud-1/CC2D1A, a transcriptional repressor of the 5-HT1A receptor, in the prefrontal cortex of subjects with major depression.

    PubMed

    Szewczyk, Bernadeta; Albert, Paul R; Rogaeva, Anastasia; Fitzgibbon, Heidi; May, Warren L; Rajkowska, Grazyna; Miguel-Hidalgo, Jose J; Stockmeier, Craig A; Woolverton, William L; Kyle, Patrick B; Wang, Zhixia; Austin, Mark C

    2010-09-01

    Serotonin1A (5-HT(1A)) receptors are reported altered in the brain of subjects with major depressive disorder (MDD). Recent studies have identified transcriptional regulators of the 5-HT(1A) receptor and have documented gender-specific alterations in 5-HT(1A) transcription factor and 5-HT(1A) receptors in female MDD subjects. The 5' repressor element under dual repression binding protein-1 (Freud-1) is a calcium-regulated repressor that negatively regulates the 5-HT(1A) receptor gene. This study documented the cellular expression of Freud-1 in the human prefrontal cortex (PFC) and quantified Freud-1 protein in the PFC of MDD and control subjects as well as in the PFC of rhesus monkeys chronically treated with fluoxetine. Freud-1 immunoreactivity was present in neurons and glia and was co-localized with 5-HT(1A) receptors. Freud-1 protein level was significantly decreased in the PFC of male MDD subjects (37%, p=0.02) relative to gender-matched control subjects. Freud-1 protein was also reduced in the PFC of female MDD subjects (36%, p=0.18) but was not statistically significant. When the data was combined across genders and analysed by age, the decrease in Freud-1 protein level was greater in the younger MDD subjects (48%, p=0.01) relative to age-matched controls as opposed to older depressed subjects. Similarly, 5-HT(1A) receptor protein was significantly reduced in the PFC of the younger MDD subjects (48%, p=0.01) relative to age-matched controls. Adult male rhesus monkeys administered fluoxetine daily for 39 wk revealed no significant change in cortical Freud-1 or 5-HT(1A) receptor proteins compared to vehicle-treated control monkeys. Reduced protein expression of Freud-1 in MDD subjects may reflect dysregulation of this transcription factor, which may contribute to the altered regulation of 5-HT(1A) receptors observed in subjects with MDD. These data may also suggest that reductions in Freud-1 protein expression in the PFC may be associated with early onset of

  18. Citrus aurantium L. essential oil exhibits anxiolytic-like activity mediated by 5-HT1A-receptors and reduces cholesterol after repeated oral treatment

    PubMed Central

    2013-01-01

    Background The current treatments for anxiety disorders and depression have multiple adverse effects in addition to a delayed onset of action, which has prompted efforts to find new substances with potential activity in these disorders. Citrus aurantium was chosen based on ethnopharmacological data because traditional medicine refers to the Citrus genus as useful in diminishing the symptoms of anxiety or insomnia, and C. aurantium has more recently been proposed as an adjuvant for antidepressants. In the present work, we investigated the biological activity underlying the anxiolytic and antidepressant effects of C. aurantium essential oil (EO), the putative mechanism of the anxiolytic-like effect, and the neurochemical changes in specific brain structures of mice after acute treatment. We also monitored the mice for possible signs of toxicity after a 14-day treatment. Methods The anxiolytic-like activity of the EO was investigated in a light/dark box, and the antidepressant activity was investigated in a forced swim test. Flumazenil, a competitive antagonist of benzodiazepine binding, and the selective 5-HT1A receptor antagonist WAY100635 were used in the experimental procedures to determine the mechanism of action of the EO. To exclude false positive results due to motor impairment, the mice were submitted to the rotarod test. Results The data suggest that the anxiolytic-like activity observed in the light/dark box procedure after acute (5 mg/kg) or 14-day repeated (1 mg/kg/day) dosing was mediated by the serotonergic system (5-HT1A receptors). Acute treatment with the EO showed no activity in the forced swim test, which is sensitive to antidepressants. A neurochemical evaluation showed no alterations in neurotransmitter levels in the cortex, the striatum, the pons, and the hypothalamus. Furthermore, no locomotor impairment or signs of toxicity or biochemical changes, except a reduction in cholesterol levels, were observed after treatment with the EO. Conclusion

  19. No evidence that MDMA-induced enhancement of emotional empathy is related to peripheral oxytocin levels or 5-HT1a receptor activation.

    PubMed

    Kuypers, Kim P C; de la Torre, Rafael; Farre, Magi; Yubero-Lahoz, Samanta; Dziobek, Isabel; Van den Bos, Wouter; Ramaekers, Johannes G

    2014-01-01

    The present study aimed at investigating the effect of MDMA on measures of empathy and social interaction, and the roles of oxytocin and the 5-HT1A receptor in these effects. The design was placebo-controlled within-subject with 4 treatment conditions: MDMA (75 mg), with or without pindolol (20 mg), oxytocin nasal spray (40 IU+16 IU) or placebo. Participants were 20 healthy poly-drug MDMA users, aged between 18-26 years. Cognitive and emotional empathy were assessed by means of the Reading the Mind in the Eyes Test and the Multifaceted Empathy Test. Social interaction, defined as trust and reciprocity, was assessed by means of a Trust Game and a Social Ball Tossing Game. Results showed that MDMA selectively affected emotional empathy and left cognitive empathy, trust and reciprocity unaffected. When combined with pindolol, these effects remained unchanged. Oxytocin did not affect measures of empathy and social interaction. Changes in emotional empathy were not related to oxytocin plasma levels. It was concluded that MDMA (75 mg) selectively enhances emotional empathy in humans. While the underlying neurobiological mechanism is still unknown, it is suggested that peripheral oxytocin does not seem to be the main actor in this; potential candidates are the serotonin 2A and the vasopressin 1A receptors. Trial registration: MDMA & PSB NTR 2636.

  20. Methylation at a transcription factor-binding site on the 5-HT1A receptor gene correlates with negative symptom treatment response in first episode schizophrenia.

    PubMed

    Tang, Hao; Dalton, Caroline F; Srisawat, Umarat; Zhang, Zhi Jun; Reynolds, Gavin P

    2014-04-01

    Individual variability and inadequate response of negative symptoms are major limitations of antipsychotic treatment in schizophrenia. A functional polymorphism, rs6295, in the 5-HT1A-receptor gene (HTR1A) contributes to this variability in negative symptom response. The DNA sequence containing rs6295 is rich in cytosine methylation (CpG) sites; CpG methylation is an epigenetic factor that, like rs6295, can modify transcriptional control. To investigate whether DNA methylation influences response to antipsychotic treatment, we determined methylation at CpG sites close to rs6295 in DNA from 82 Chinese subjects with a first psychotic episode. Methylation of one CpG site within a recognition sequence for HES transcriptional repressors was found to correlate with changes in total PANSS score (p = 0.006) and negative factor sub-score (p < 0.001) following 10 wk initial antipsychotic treatment, as well as with baseline negative factor score (p = 0.019); the effect on symptom change remained after correction for this baseline score. An effect of rs6295 on negative symptom response was not seen in this sample, which may not have provided sufficient power for the pharmacogenetic association. These preliminary results indicate that epigenetic modification of transcriptional regulation by specific cytosine methylation may modulate HTR1A expression, resulting in effects on emotional dysfunction and negative symptom response to antipsychotic treatment. PMID:24331356

  1. Systemic modulation of serotonergic synapses via reuptake blockade or 5HT1A receptor antagonism does not alter perithreshold taste sensitivity in rats.

    PubMed

    Mathes, Clare M; Spector, Alan C

    2014-09-01

    Systemic blockade of serotonin (5HT) reuptake with paroxetine has been shown to increase sensitivity to sucrose and quinine in humans. Here, using a 2-response operant taste detection task, we measured the effect of paroxetine and the 5HT1A receptor antagonist WAY100635 on the ability of rats to discriminate sucrose, NaCl, and citric acid from water. After establishing individual psychometric functions, 5 concentrations of each taste stimulus were chosen to represent the dynamic portion of the concentration-response curve, and the performance of the rats to these stimuli was assessed after vehicle, paroxetine (7mg/kg intraperitoneally), and WAY100635 (0.3mg/kg subcutaneously; 1mg/kg intravenously) administration. Although, at times, overall performance across concentrations dropped, at most, 5% from vehicle to drug conditions, no differences relative to vehicle were seen on the parameters of the psychometric function (asymptote, slope, or EC50) after drug administration. In contrast to findings in humans, our results suggest that modulation of 5HT activity has little impact on sucrose detectability at perithreshold concentrations in rats, at least at the doses used in this task. In the rat model, the purported paracrine/neurocrine action of serotonin in the taste bud may work in a manner that does not impact overt taste detection behavior.

  2. An Algorithm to Identify Target-Selective Ligands – A Case Study of 5-HT7/5-HT1A Receptor Selectivity

    PubMed Central

    Kurczab, Rafał; Canale, Vittorio; Zajdel, Paweł; Bojarski, Andrzej J.

    2016-01-01

    A computational procedure to search for selective ligands for structurally related protein targets was developed and verified for serotonergic 5-HT7/5-HT1A receptor ligands. Starting from a set of compounds with annotated activity at both targets (grouped into four classes according to their activity: selective toward each target, not-selective and not-selective but active) and with an additional set of decoys (prepared using DUD methodology), the SVM (Support Vector Machines) models were constructed using a selective subset as positive examples and four remaining classes as negative training examples. Based on these four component models, the consensus classifier was then constructed using a data fusion approach. The combination of two approaches of data representation (molecular fingerprints vs. structural interaction fingerprints), different training set sizes and selection of the best SVM component models for consensus model generation, were evaluated to determine the optimal settings for the developed algorithm. The results showed that consensus models with molecular fingerprints, a larger training set and the selection of component models based on MCC maximization provided the best predictive performance. PMID:27271158

  3. Depressed GABA and glutamate synaptic signaling by 5-HT1A receptors in the nucleus tractus solitarii and their role in cardiorespiratory function

    PubMed Central

    Ostrowski, Tim D.; Ostrowski, Daniela; Hasser, Eileen M.

    2014-01-01

    Serotonin (5-HT), and its 5-HT1A receptor (5-HT1AR) subtype, is a powerful modulator of the cardiorespiratory system and its sensory reflexes. The nucleus tractus solitarii (nTS) serves as the first central station for visceral afferent integration and is critical for cardiorespiratory reflex responses. However, the physiological and synaptic role of 5-HT1ARs in the nTS is relatively unknown. In the present study, we examined the distribution and modulation of 5-HT1ARs on cardiorespiratory and synaptic parameters in the nTS. 5-HT1ARs were widely distributed to cell bodies within the nTS but not synaptic terminals. In anesthetized rats, activation of 5-HT1ARs by microinjection of the 5-HT1AR agonist 8-OH-DPAT into the caudal nTS decreased minute phrenic neural activity via a reduction in phrenic amplitude. In brain stem slices, 8-OH-DPAT decreased the amplitude of glutamatergic tractus solitarii-evoked excitatory postsynaptic currents, and reduced overall spontaneous excitatory nTS network activity. These effects persisted in the presence of GABAA receptor blockade and were antagonized by coapplication of 5-HT1AR blocker WAY-100135. 5-HT1AR blockade alone had no effect on tractus solitarii-evoked excitatory postsynaptic currents, but increased excitatory network activity. On the other hand, GABAergic nTS-evoked inhibitory postsynaptic currents did not change by activation of the 5-HT1ARs, but spontaneous inhibitory nTS network activity decreased. Blocking 5-HT1ARs tended to increase nTS-evoked inhibitory postsynaptic currents and inhibitory network activity. Taken together, 5-HT1ARs in the caudal nTS decrease breathing, likely via attenuation of afferent transmission, as well as overall nTS network activity. PMID:24671532

  4. Occupancy of dopamine D2 and D3 and serotonin 5-HT1A receptors by the novel antipsychotic drug candidate, cariprazine (RGH-188), in monkey brain measured using positron emission tomography

    PubMed Central

    Seneca, Nicholas; Finnema, Sjoerd J.; Laszlovszky, István; Kiss, Béla; Horváth, Attila; Pásztor, Gabriella; Kapás, Margó; Gyertyán, István; Farkas, Sándor; Innis, Robert B.; Halldin, Christer

    2011-01-01

    Rationale Cariprazine is a novel antipsychotic drug candidate that exhibits high selectivity and affinity to dopamine D3 and D2 receptors and moderate affinity to serotonin 5-HT1A receptors. Targeting receptors other than D2 may provide a therapeutic benefit for both positive and negative symptoms associated with schizophrenia. Positron emission tomography (PET) can be used as a tool in drug development to assess the in vivo distribution and pharmacological properties of a drug. Objectives The objective of this study was to determine dopamine D2/D3 and serotonin 5-HT1A receptor occupancy in monkey brain after the administration of cariprazine. Methods We examined three monkeys using the following PET radioligands: [11C]MNPA (an agonist at D2 and D3 receptors), [11C]raclopride (an antagonist at D2 and D3 receptors), and [11C]WAY-100635 (an antagonist at 5-HT1A receptors). During each experimental day, the first PET measurement was a baseline study, the second after a low dose of cariprazine, and the third after the administration of a high dose. Results We found that cariprazine occupied D2/D3 receptors in a dose-dependent and saturable manner, with the lowest dose occupying ~5% of receptors and the highest dose showing more than 90% occupancy. 5-HT1A receptor occupancy was considerably lower compared with D2/D3 occupancy at the same doses, with a maximal value of ~30% for the raphe nuclei. Conclusions We conclude that cariprazine binds preferentially to dopamine D2/D3 rather than to serotonin 5-HT1A receptors in monkey brain. These findings can be used to guide the selection of cariprazine dosing in humans. PMID:21625907

  5. Evaluation of a combined treatment paradigm consisting of environmental enrichment and the 5-HT1A receptor agonist buspirone after experimental traumatic brain injury.

    PubMed

    Kline, Anthony E; Olsen, Adam S; Sozda, Christopher N; Hoffman, Ann N; Cheng, Jeffrey P

    2012-07-01

    Environmental enrichment (EE) and serotonin(1A) (5-HT(1A))-receptor agonists provide significant benefit after experimental traumatic brain injury (TBI). The aim of this study was to test the hypothesis that combining these therapies would produce an effect that is more robust than either therapy alone. Anesthetized adult male rats received a cortical impact or sham injury and then were randomly assigned to EE or standard (STD) housing where they received either buspirone (0.3 mg/kg) or vehicle (1.0 mL/kg) once daily for 3 weeks. Motor and cognitive assessments were conducted on post-injury days 1-5 and 14-19, respectively. CA1/3 neurons were quantified at 3 weeks. No differences were observed among buspirone and vehicle sham groups in any task regardless of housing condition and thus the data were pooled. CA3 cell loss was reduced in the TBI+EE+buspirone and TBI+EE+vehicle groups. Motor recovery, spatial learning, and memory retention were enhanced in the TBI+EE+buspirone, TBI+EE+vehicle, and TBI+STD+buspirone groups versus the TBI+STD+vehicle group (p ≤ 0.005). Moreover, spatial learning was significantly better in the TBI+EE+buspirone group versus the TBI+STD+buspirone group (p<0.0001). No differences were revealed between the buspirone and vehicle EE groups. These data show that EE and buspirone benefit functional outcome after TBI, but their combination is not more robust than either alone, which does not support the hypothesis. The lack of an additive effect may be due to the early-and-continuous EE paradigm on its own producing marked benefits, resulting in a ceiling effect. The evaluation of buspirone in a delayed-and-abbreviated EE paradigm is ongoing in our laboratory.

  6. Acute treatment with the 5-HT(1A) receptor agonist 8-OH-DPAT and chronic environmental enrichment confer neurobehavioral benefit after experimental brain trauma.

    PubMed

    Kline, Anthony E; Wagner, Amy K; Westergom, Brian P; Malena, Rebecca R; Zafonte, Ross D; Olsen, Adam S; Sozda, Christopher N; Luthra, Pallavi; Panda, Monisha; Cheng, Jeffery P; Aslam, Haris A

    2007-02-27

    Acute treatment with the 5-HT(1A) receptor agonist 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) or chronic environmental enrichment (EE) hasten behavioral recovery after experimental traumatic brain injury (TBI). The aim of this study was to determine if combining these interventions would confer additional benefit. Anesthetized adult male rats received either a cortical impact or sham injury followed 15min later by a single intraperitoneal injection of 8-OH-DPAT (0.5mg/kg) or saline vehicle (1.0mL/kg) and then randomly assigned to either enriched or standard (STD) housing. Behavioral assessments were conducted utilizing established motor and cognitive tests on post-injury days 1-5 and 14-18, respectively. Hippocampal CA(1)/CA(3) neurons were quantified at 3 weeks. Both 8-OH-DPAT and EE attenuated CA(3) cell loss. 8-OH-DPAT enhanced spatial learning in a Morris water maze (MWM) as revealed by differences between the TBI+8-OH-DPAT+STD and TBI+VEHICLE+STD groups (P=0.0014). EE improved motor function as demonstrated by reduced time to traverse an elevated narrow beam in both the TBI+8-OH-DPAT+EE and TBI+VEHICLE+EE groups versus the TBI+VEHICLE+STD group (P=0.0007 and 0.0016, respectively). EE also facilitated MWM learning as evidenced by both the TBI+8-OH-DPAT+EE and TBI+VEHICLE+EE groups locating the escape platform quicker than the TBI+VEHICLE+STD group (P's<0.0001). MWM differences were also observed between the TBI+8-OH-DPAT+EE and TBI+8-OH-DPAT+STD groups (P=0.0004) suggesting that EE enhanced the effect of 8-OH-DPAT. However, there was no difference between the TBI+8-OH-DPAT+EE and TBI+VEHICLE+EE groups. These data replicate previous results from our laboratory showing that both a single systemic administration of 8-OH-DPAT and EE improve recovery after TBI and extend those findings by elucidating that the combination of treatments in this particular paradigm did not confer additional benefit. One explanation for the lack of an additive effect is that EE

  7. Acute treatment with the 5-HT1A receptor agonist 8-OH-DPAT and chronic environmental enrichment confer neurobehavioral benefit after experimental brain trauma

    PubMed Central

    Kline, Anthony E.; Wagner, Amy K.; Westergom, Brian P.; Malena, Rebecca R.; Zafonte, Ross D.; Olsen, Adam S.; Sozda, Christopher N.; Luthra, Pallavi; Panda, Monisha; Cheng, Jeffery P.; Aslam, Haris A.

    2007-01-01

    Acute treatment with the 5-HT1A receptor agonist 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) or chronic environmental enrichment (EE) hasten behavioral recovery after experimental traumatic brain injury (TBI). The aim of this study was to determine if combining these interventions would confer additional benefit. Anesthetized adult male rats received either a cortical impact or sham injury followed 15 min later by a single intraperitoneal injection of 8-OH-DPAT (0.5 mg/kg) or saline vehicle (1.0 mL/kg) and then randomly assigned to either enriched or standard (STD) housing. Behavioral assessments were conducted utilizing established motor and cognitive tests on post-injury days 1-5 and 14-18, respectively. Hippocampal CA1/CA3 neurons were quantified at 3 weeks. Both 8-OH-DPAT and EE attenuated CA3 cell loss. 8-OH-DPAT enhanced spatial learning in a Morris water maze (MWM) as revealed by differences between the TBI+8-OH-DPAT+STD and TBI+VEHICLE+STD groups (P=0.0014). EE improved motor function as demonstrated by reduced time to traverse an elevated narrow beam in both the TBI+8-OH-DPAT+EE and TBI+VEHICLE+EE groups vs. the TBI+VEHICLE+STD group (P=0.0007 and P=0.0016, respectively). EE also facilitated MWM learning as evidenced by both the TBI+8-OH-DPAT+EE and TBI+VEHICLE+EE groups locating the escape platform quicker than the TBI+VEHICLE+STD group (P's<0.0001). MWM differences were also observed between the TBI+8-OH-DPAT+EE and TBI+8-OH-DPAT+STD groups (P=0.0004) suggesting that EE enhanced the effect of 8-OH-DPAT. However, there was no difference between the TBI+8-OH-DPAT+EE and TBI+VEHICLE+EE groups. These data replicate previous results from our laboratory showing that both a single systemic administration of 8-OH-DPAT and EE improve recovery after TBI and extend those findings by elucidating that the combination of treatments in this particular paradigm did not confer additional benefit. One explanation for the lack of an additive effect is that EE is a

  8. 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.

  9. Linoleic acid derivative DCP-LA ameliorates stress-induced depression-related behavior by promoting cell surface 5-HT1A receptor translocation, stimulating serotonin release, and inactivating GSK-3β.

    PubMed

    Kanno, Takeshi; Tanaka, Akito; Nishizaki, Tomoyuki

    2015-04-01

    Impairment of serotonergic neurotransmission is the major factor responsible for depression and glycogen synthase kinase 3β (GSK-3β) participates in serotonergic transmission-mediated signaling networks relevant to mental illnesses. In the forced-swim test to assess depression-like behavior, the immobility time for mice with restraint stress was significantly longer than that for nonstressed control mice. Postsynaptic cell surface localization of 5-HT1A receptor, but not 5-HT2A receptor, in the hypothalamus for mice with restraint stress was significantly reduced as compared with that for control mice, which highly correlated to prolonged immobility time, i.e., depression-like behavior. The linoleic acid derivative 8-[2-(2-pentyl-cyclopropylmethyl)-cyclopropyl]-octanoic acid (DCP-LA) restored restraint stress-induced reduction of cell surface 5-HT1A receptor and improved depression-like behavior in mice with restraint stress. Moreover, DCP-LA stimulated serotonin release from hypothalamic slices and cancelled restraint stress-induced reduction of GSK-3β phosphorylation at Ser9. Taken together, the results of the present study indicate that DCP-LA could ameliorate depression-like behavior by promoting translocation of 5-HT1A receptor to the plasma membrane on postsynaptic cells, stimulating serotonin release, and inactivating GSK-3β.

  10. Rapid activation of sodium-proton exchange and extracellular signal-regulated protein kinase in fibroblasts by G protein-coupled 5-HT1A receptor involves distinct signalling cascades.

    PubMed Central

    Garnovskaya, M N; Mukhin, Y; Raymond, J R

    1998-01-01

    These experiments tested the hypothesis that signalling elements involved in the activation of the extracellular signal-regulated protein kinase (ERK) mediate rapid activation of sodium-proton exchange (NHE) in fibroblasts when both signals are initiated by a single G protein-coupled receptor, the 5-HT1A receptor. Similarities between the two processes were comparable concentration-response curves and time-courses, and overlapping sensitivity to some pharmacological inhibitors of tyrosine kinases (staurosporine and genistein), and phosphoinositide 3'-kinase (wortmannin and LY204002). Activation of NHE was much more sensitive to the phosphatidylcholine-specific phospholipase inhibitor (D609) than was ERK. Neither pathway was sensitive to manoeuvres designed to block PKC. In contrast, Src or related kinases appear to be required to activate ERK, but not NHE. Transfection of cDNA constructs encoding inactive mutant phosphoinositide 3'-kinase, Grb2, Sos, Ras, and Raf molecules were successful in attenuating ERK, but had essentially no effect upon NHE activation. Finally, PD98059, an inhibitor of mitogen activated/extracellular signal regulated kinase kinase, blocked ERK but not NHE activation. Thus, in CHO fibroblast cells, activation by the 5-HT1A receptor of ERK and NHE share a number of overlapping features. However, our studies do not support a major role for ERK, when activated by the 5-HT1A receptor, as a short-term upstream regulator of NHE activity. PMID:9461547

  11. Combined serotonin (5-HT)1A agonism, 5-HT(2A) and dopamine D₂ receptor antagonism reproduces atypical antipsychotic drug effects on phencyclidine-impaired novel object recognition in rats.

    PubMed

    Oyamada, Yoshihiro; Horiguchi, Masakuni; Rajagopal, Lakshmi; Miyauchi, Masanori; Meltzer, Herbert Y

    2015-05-15

    Subchronic administration of an N-methyl-D-aspartate receptor (NMDAR) antagonist, e.g. phencyclidine (PCP), produces prolonged impairment of novel object recognition (NOR), suggesting they constitute a hypoglutamate-based model of cognitive impairment in schizophrenia (CIS). Acute administration of atypical, e.g. lurasidone, but not typical antipsychotic drugs (APDs), e.g. haloperidol, are able to restore NOR following PCP (acute reversal model). Furthermore, atypical APDs, when co-administered with PCP, have been shown to prevent development of NOR deficits (prevention model). Most atypical, but not typical APDs, are more potent 5-HT(2A) receptor inverse agonists than dopamine (DA) D2 antagonists, and have been shown to enhance cortical and hippocampal efflux and to be direct or indirect 5-HT(1A) agonists in vivo. To further clarify the importance of these actions to the restoration of NOR by atypical APDs, sub-effective or non-effective doses of combinations of the 5-HT(1A) partial agonist (tandospirone), the 5-HT(2A) inverse agonist (pimavanserin), or the D2 antagonist (haloperidol), as well as the combination of all three agents, were studied in the acute reversal and prevention PCP models of CIS. Only the combination of all three agents restored NOR and prevented the development of PCP-induced deficit. Thus, this triple combination of 5-HT(1A) agonism, 5-HT(2A) antagonism/inverse agonism, and D2 antagonism is able to mimic the ability of atypical APDs to prevent or ameliorate the PCP-induced NOR deficit, possibly by stimulating signaling cascades from D1 and 5-HT(1A) receptor stimulation, modulated by D2 and 5-HT(2A) receptor antagonism. PMID:25448429

  12. Classification of 5-HT1A Receptor Ligands on the Basis of Their Binding Affinities by Using PSO-Adaboost-SVM

    PubMed Central

    Cheng, Zhengjun; Zhang, Yuntao; Zhou, Changhong; Zhang, Wenjun; Gao, Shibo

    2009-01-01

    In the present work, the support vector machine (SVM) and Adaboost-SVM have been used to develop a classification model as a potential screening mechanism for a novel series of 5-HT1A selective ligands. Each compound is represented by calculated structural descriptors that encode topological features. The particle swarm optimization (PSO) and the stepwise multiple linear regression (Stepwise-MLR) methods have been used to search descriptor space and select the descriptors which are responsible for the inhibitory activity of these compounds. The model containing seven descriptors found by Adaboost-SVM, has showed better predictive capability than the other models. The total accuracy in prediction for the training and test set is 100.0% and 95.0% for PSO-Adaboost-SVM, 99.1% and 92.5% for PSO-SVM, 99.1% and 82.5% for Stepwise-MLR-Adaboost-SVM, 99.1% and 77.5% for Stepwise-MLR-SVM, respectively. The results indicate that Adaboost-SVM can be used as a useful modeling tool for QSAR studies. PMID:20111683

  13. Effect of Chaihu-Shugan-San on the mRNA expression of the 5-HT1A receptor and cellular proliferation in the hippocampus of epileptic rats with depression

    PubMed Central

    YANG, PING; LI, LIANG; LIU, XUE-JUN; CAI, XIONG; SUN, MEI-ZHEN; HE, JUN-FENG; ZENG, GUANG; HUANG, HUI-YONG

    2016-01-01

    Chaihu-Shugan-San (CHSGS) is a herbal preparation that has been shown to effectively relieve neurologic impairment and reduce depression. However, the efficacy of CHSGS in the treatment of patients with epilepsy with depression is unknown. Therefore, in the present study, adult rats were exposed to chronic mild stress following the establishment of chronic pilocarpine-induced epilepsy. Subsequently, a sucrose consumption test and open-field test (OFT) were performed to assess depression-like behavior. Rats were randomly divided into four groups: Control, model, fluoxetine (1.8 g/kg) and CHSGS (2.7 g/kg) groups. The control and model groups received normal saline. The mRNA expression levels of the 5-hydroxytryptamine 1A (5-HT1A) receptor and the number of 5-bromo-2′-deoxyuridine (BrdU)-labeled cells in the hippocampal dentate gyrus were detected using reverse transcription-quantitative polymerase chain reaction and immunohistochemical analysis, respectively. Treatment administration was conducted by once daily intragastric perfusion for 28 days. The mRNA expression levels of the 5-HT1A receptor, the number of BrdU-labeled cells in the hippocampal dentate gyrus, the consumption of sucrose, and frequency of vertical and horizontal movement scores in the OFT were enhanced in the fluoxetine and CHSGS groups compared with the model group (P<0.05). However, no statistically significant difference was detected between the fluoxetine and CHSGS groups. These data suggest that CHSGS is able to increase the expression of 5-HT1A receptor mRNA and cellular proliferation in the hippocampal dentate gyrus in epileptic rats with depression, and thus effectively improve certain symptoms of depression. PMID:26889228

  14. Serotonin 5-HT1A and 5-HT2/1C receptors in the midbrain periaqueductal gray differentially modulate defensive rage behavior elicited from the medial hypothalamus of the cat.

    PubMed

    Shaikh, M B; De Lanerolle, N C; Siegel, A

    1997-08-15

    Recent studies have established that the expression of defensive rage behavior in the cat is mediated over a descending pathway from the medial hypothalamus to the dorsolateral quadrant of the midbrain periaqueductal gray matter (PAG). The present study was designed to determine the roles played by 5-HT1A and 5-HT2/1C receptors in this region of PAG in modulating defensive rage behavior elicited from the cat's medial hypothalamus. Monopolar stimulating electrodes were implanted into the medial hypothalamus from which defensive rage behavior could be elicited by electrical stimulation. During the course of the study, the 'hissing' component of the defensive rage response was used as a measure of defensive rage behavior. Cannula-electrodes were implanted into sites within the PAG from which defensive rage could also be elicited by electrical stimulation in order that 5-HT compounds could be microinjected into behaviorally identifiable regions of the PAG at a later time. Microinjections of the selective 5-HT1A agonist, (+)-8-hydroxy-dipropylaminotetralin hydrobromide (8-OHDPAT) (50 pmol, 2.0 and 3.0 nmol), into the PAG suppressed the hissing response in a dose-dependent manner. Administration of the selective 5-HT1A antagonist, 4-iodo-N-[2-[4-(methoxyphenyl)-1-piperazinyl] ethyl]-N-2-pyridinyl-benzamide hydrochloride (p-MPPI) (1.5 and 3.0 nmol), blocked the suppressive effects of 8-OHDPAT upon hissing. In contrast, microinjections of the 5-HT2/1C receptor agonist (+)-1-(4-iodo-2,5-dimethoxyphenyl)-2-aminopropane hydrochloride ((+)-DOI hydrochloride) (0.01, 1.0 and 1.5 nmol) facilitated the occurrence of hissing elicited from the medial hypothalamus in a dose-dependent manner. Immunohistochemical analysis revealed the presence of 5-HT axons and preterminals throughout the PAG, and in particular, in its dorsolateral aspect which receives major inputs from the medial hypothalamus in association with defensive rage behavior. The overall findings of the study provide

  15. 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. PMID:23926240

  16. 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.

  17. Synthesis and structure-affinity relationships of novel small molecule natural product derivatives capable of discriminating between serotonin 5-HT1A, 5-HT2A, 5-HT2C receptor subtypes

    PubMed Central

    Cummings, David F.; Canseco, Diana C.; Sheth, Pratikkumar; Johnson, James E.; Schetz, John A.

    2010-01-01

    Efforts to develop ligands that distinguish between clinically relevant 5-HT2A and 5-HT2C serotonin receptor subtypes have been challenging, because their sequences have high homology. Previous studies reported that a novel aplysinopsin belonging to a chemical class of natural products isolated from a marine sponge was selective for the 5-HT2C over the 5-HT2A receptor subtype. Our goal was to explore the 5-HT2A/2C receptor structure-affinity relationships of derivatives based on the aplysinopsin natural product pharmacophore. Twenty aplysinopsin derivatives were synthesized, purified and tested for their affinities for cloned human serotonin 5-HT1A, 5-HT2A and 5-HT2C receptor subtypes. Four compounds in this series had >30-fold selectivity for 5-HT2A or 5-HT2C receptors. The compound (E)-5-((5,6-dichloro-1H-indol-3-yl)methylene)-2-imino-1,3-dimethylimidazolidin-4-one (UNT-TWU-22, 16) had approximately 2100-fold selectivity for the serotonin 5-HT2C receptor subtype: an affinity for 5-HT2C equal to 46 nM and no detectable affinity for the 5-HT1A or 5-HT2A receptor subtypes. The two most important factors controlling 5-HT2A or 5-HT2C receptor subtype selectivity were the combined R1, R3-alkylation of the imidazolidinone ring and the type and number of halogens on the indole ring of the aplysinopsin pharmacophore. PMID:20570529

  18. The antidepressant-like activity of 6-methoxy-2-[4-(2-methoxyphenyl)piperazin-1-yl]-9H-xanthen-9-one involves serotonergic 5-HT(1A) and 5-HT(2A/C) receptors activation.

    PubMed

    Pytka, Karolina; Walczak, Maria; Kij, Agnieszka; Rapacz, Anna; Siwek, Agata; Kazek, Grzegorz; Olczyk, Adrian; Gałuszka, Adam; Waszkielewicz, Anna; Marona, Henryk; Sapa, Jacek; Filipek, Barbara

    2015-10-01

    Xanthone derivatives have been shown to posses many biological properties. Some of them act within the central nervous system and show neuroprotective or antidepressant-like properties. Taking this into account we investigated antidepressant-like activity in mice and the possible mechanism of action of 6-methoxy-2-[4-(2-methoxyphenyl)piperazin-1-yl]-9H-xanthen-9-one (HBK-11) - a new xanthone derivative. We demonstrated that HBK-11 produced antidepressant-like effects in the forced swim test and tail suspension test, comparable to that of venlafaxine. The combined treatment with sub-effective doses of HBK-11 and fluoxetine (but not reboxetine or bupropion) significantly reduced the immobility in the forced swim test. Moreover, the antidepressant-like activity of HBK-11 in the aforementioned test was blocked by p-chlorophenylalanine, and significantly reduced by serotonergic 5HT1A receptor antagonist - WAY-1006335 and 5HT2A/C receptor antagonist - ritanserin. As none of the above treatments influenced the spontaneous locomotor activity, it can be concluded that HBK-11 mediates its activity through a serotonergic system, and its antidepressant-like effect involves 5HT1A and 5HT2A/C receptor activation. Furthermore, at antidepressant-like doses HBK-11 did not cause the mice to display locomotor deficits in rotarod or chimney tests. Considering the pharmacokinetic profile, HBK-11 demonstrated rapid absorption after i.p. administration, high clearance value, short terminal half-life, very high volume of distribution and incomplete bioavailability. The compound studied had good penetration into the brain tissue of mice. Since studied xanthone derivative seems to present interesting, untypical mechanism of antidepressant-like action i.e. 5HT2A/C receptor activation, it may have a potential in the treatment of depressive disorders, and surely requires further studies. PMID:26210317

  19. 5-HT1A/1B, 5-HT6, and 5-HT7 serotonergic receptors recruitment in tonic-clonic seizure-induced antinociception: role of dorsal raphe nucleus.

    PubMed

    Freitas, Renato Leonardo; Ferreira, Célio Marcos dos Reis; Urbina, Maria Angélica Castiblanco; Mariño, Andrés Uribe; Carvalho, Andressa Daiane; Butera, Giuseppe; de Oliveira, Ana Maria; Coimbra, Norberto Cysne

    2009-05-01

    Pharmacological studies have been focused on the involvement of different neural pathways in the organization of antinociception that follows tonic-clonic seizures, including 5-hydroxytryptamine (5-HT)-, norepinephrine-, acetylcholine- and endogenous opioid peptide-mediated mechanisms, giving rise to more in-depth comprehension of this interesting post-ictal antinociceptive phenomenon. The present work investigated the involvement of 5-HT(1A/1B), 5-HT(6), and 5-HT(7) serotonergic receptors through peripheral pretreatment with methiothepin at doses of 0.5, 1.0, 2.0 and 3.0 mg/kg in the organization of the post-ictal antinociception elicited by pharmacologically (with pentylenetetrazole at 64 mg/kg)-induced tonic-clonic seizures. Methiothepin at 1.0 mg/kg blocked the post-ictal antinociception recorded after the end of seizures, whereas doses of 2.0 and 3.0 mg/kg potentiated the post-ictal antinociception. The nociceptive thresholds were kept higher than those of the control group. However, when the same 5-hydroxytryptamine receptors antagonist was microinjected (at 1.0, 3.0 and 5.0 microg/0.2 microL) in the dorsal raphe nucleus, a mesencephalic structure rich in serotonergic neurons and 5-HT receptors, the post-ictal hypo-analgesia was consistently antagonized. The present findings suggest a dual effect of methiothepin, characterized by a disinhibitory effect on the post-ictal antinociception when peripherally administered (possibly due to an antagonism of pre-synaptic 5-HT(1A) serotonergic autoreceptors in the pain endogenous inhibitory system) and an inhibitory effect (possibly due to a DRN post-synaptic 5-HT(1B), 5-HT(6), and 5-HT(7) serotonergic receptors blockade) when centrally administered. The present data also suggest that serotonin-mediated mechanisms of the dorsal raphe nucleus exert a key-role in the modulation of the post-ictal antinociception.

  20. GPER1 stimulation alters posttranslational modification of RGSz1 and induces desensitization of 5-HT1A receptor signaling in the rat hypothalamus

    PubMed Central

    McAllister, Carrie E; Mi, Zhen; Mure, Minae; Li, Qian; Muma, Nancy A

    2014-01-01

    Hyperactivity of the hypothalamic-pituitary-adrenal axis is a consistent biological characteristic of depression and response normalization coincides with clinical responsiveness to antidepressant medications. Desensitization of serotonin 1A receptor (5-HT1AR) signaling in the hypothalamic paraventricular nucleus (PVN) follows selective serotonin reuptake inhibitor (SSRI) antidepressant treatment and contributes to the antidepressant response. Estradiol alone produces a partial desensitization of 5-HT1AR signaling, and synergizes with SSRIs to result in a complete and more rapid desensitization than with SSRIs alone as measured by a decrease in the oxytocin and adrenocorticotrophic hormone(ACTH) responses to 5-HT1AR stimulation. G protein-coupled estrogen receptor1 (GPER1) is necessary for estradiol-induced desensitization of 5-HT1AR signaling, although the underlying mechanisms are still unclear. We now find that stimulation of GPER1 with the selective agonist G-1 and non-selective stimulation of estrogen receptors dramatically alter isoform expression of a key component of the 5-HT1AR signaling pathway, RGSz1, a GTPase activating protein selective for Gαz, the Gα subunit necessary for 5-HT1AR-mediated hormone release. RGSz1 isoforms are differentially glycosylated, SUMOylated, and phosphorylated, and differentially distributed in subcellular organelles. High molecular weight RGSz1 is SUMOylated and glycosylated, localized to the detergent-resistant microdomain (DRM) of the cell membrane, and increased by estradiol and G-1 treatment. Because activated Gαz also localizes to the DRM, increased DRM-localized RGSz1 by estradiol and G-1could reduce Gαz activity, functionally uncoupling 5-HT1AR signaling. Peripheral G-1 treatment produced partial reduction in oxytocin and ACTH responses to 5-HT1AR-stimulation similar to direct injections into the PVN. Together, these results identify GPER1 and RGSz1 as novel targets for the treatment of depression. PMID:25402859

  1. Serotonergic 5-HT(1A) receptor agonist (8-OH-DPAT) ameliorates impaired micturition reflexes in a chronic ventral root avulsion model of incomplete cauda equina/conus medullaris injury.

    PubMed

    Chang, Huiyi H; Havton, Leif A

    2013-01-01

    Trauma to the thoracolumbar spine commonly results in injuries to the cauda equina and the lumbosacral portion of the spinal cord. Both complete and partial injury syndromes may follow. Here, we tested the hypothesis that serotonergic modulation may improve voiding function after an incomplete cauda equina/conus medullaris injury. For this purpose, we used a unilateral L5-S2 ventral root avulsion (VRA) injury model in the rat to mimic a partial lesion to the cauda equina and conus medullaris. Compared to a sham-operated series, comprehensive urodynamic studies demonstrated a markedly reduced voiding efficiency at 12 weeks after the VRA injury. Detailed cystometrogram studies showed injury-induced decreased peak bladder pressures indicative of reduced contractile properties. Concurrent external urethral sphincter (EUS) electromyography demonstrated shortened burst and prolonged silent periods associated with the elimination phase. Next, a 5-HT(1A) receptor agonist, 8-hydroxy-2-(di-n-propylamino)-tetralin (8-OH-DPAT), was administered intravenously at 12 weeks after the unilateral L5-S2 VRA injury. Both voiding efficiency and maximum intravesical pressure were significantly improved by 8-OH-DPAT (0.3-1.0 mg/kg). 8-OH-DPAT also enhanced the amplitude of EUS tonic and bursting activity as well as duration of EUS bursting and silent period during EUS bursting. The results indicate that 8-OH-DPAT improves voiding efficiency and enhances EUS bursting in rats with unilateral VRA injury. We conclude that serotonergic modulation of the 5-HT(1A) receptor may represent a new strategy to improve lower urinary tract function after incomplete cauda equina/conus medullaris injuries in experimental studies.

  2. Dual role of serotonin in the acquisition and extinction of reward-driven learning: involvement of 5-HT1A, 5-HT2A and 5-HT3 receptors.

    PubMed

    Frick, Luciana Romina; Bernardez-Vidal, Micaela; Hocht, Christian; Zanutto, Bonifacio Silvano; Rapanelli, Maximiliano

    2015-01-15

    Serotonin (5-HT) has been proposed as a possible encoder of reward. Nevertheless, the role of this neurotransmitter in reward-based tasks is not well understood. Given that the major serotonergic circuit in the rat brain comprises the dorsal raphe nuclei and the medial prefrontal cortex (mPFC), and because the latter structure is involved in the control of complex behaviors and expresses 1A (5-HT1A), 2A (5-HT2A), and 3 (5-HT3) receptors, the aim was to study the role of 5-HT and of these receptors in the acquisition and extinction of a reward-dependent operant conditioning task. Long Evans rats were trained in an operant conditioning task while receiving fluoxetine (serotonin reuptake inhibitor, 10mg/kg), tianeptine (serotonin reuptake enhancer, 10mg/kg), buspirone (5-HT1A partial agonist, 10mg/kg), risperidone (5-HT2A antagonist, 1mg/kg), ondansetron (5-HT3 antagonist, 2mg/kg) or vehicle. Then, animals that acquired the operant conditioning without any treatment were trained to extinct the task in the presence of the pharmacological agents. Fluoxetine impaired acquisition but improved extinction. Tianeptine administration induced the opposite effects. Buspirone induced a mild deficit in acquisition and had no effects during the extinction phase. Risperidone administration resulted in learning deficits during the acquisition phase, although it promoted improved extinction. Ondansetron treatment showed a deleterious effect in the acquisition phase and an overall improvement in the extinction phase. These data showed a differential role of 5-HT in the acquisition and extinction of an operant conditioning task, suggesting that it may have a dual function in reward encoding. PMID:24949809

  3. Nonphotic entrainment by 5-HT1A/7 receptor agonists accompanied by reduced Per1 and Per2 mRNA levels in the suprachiasmatic nuclei.

    PubMed

    Horikawa, K; Yokota, S; Fuji, K; Akiyama, M; Moriya, T; Okamura, H; Shibata, S

    2000-08-01

    In mammals, the environmental light/dark cycle strongly synchronizes the circadian clock within the suprachiasmatic nuclei (SCN) to 24 hr. It is well known that not only photic but also nonphotic stimuli can entrain the SCN clock. Actually, many studies have shown that a daytime injection of 8-hydroxy-2-(di-n-propylamino) tetralin (8-OH DPAT), a serotonin 1A/7 receptor agonist, as a nonphotic stimulus induces phase advances in hamster behavioral circadian rhythms in vivo, as well as the neuron activity rhythm of the SCN in vitro. Recent reports suggest that mammalian homologs of the Drosophila clock gene, Period (Per), are involved in photic entrainment. Therefore, we examined whether phase advances elicited by 8-OH DPAT were associated with a change of Period mRNA levels in the SCN. In this experiment, we cloned partial cDNAs encoding hamster Per1, Per2, and Per3 and observed both circadian oscillation and the light responsiveness of Period. Furthermore, we found that the inhibitory effect of 8-OH DPAT on hamster Per1 and Per2 mRNA levels in the SCN occurred only during the hamster's mid-subjective day, but not during the early subjective day or subjective night. The present findings demonstrate that the acute and circadian time-dependent reduction of Per1 and/or Per2 mRNA in the hamster SCN by 8-OH DPAT is strongly correlated with the phase resetting in response to 8-OH DPAT. PMID:10908630

  4. The role of the serotonin receptor subtypes 5-HT1A and 5-HT7 and its interaction in emotional learning and memory

    PubMed Central

    Stiedl, Oliver; Pappa, Elpiniki; Konradsson-Geuken, Åsa; Ögren, Sven Ove

    2015-01-01

    Serotonin [5-hydroxytryptamine (5-HT)] is a multifunctional neurotransmitter innervating cortical and limbic areas involved in cognition and emotional regulation. Dysregulation of serotonergic transmission is associated with emotional and cognitive deficits in psychiatric patients and animal models. Drugs targeting the 5-HT system are widely used to treat mood disorders and anxiety-like behaviors. Among the fourteen 5-HT receptor (5-HTR) subtypes, the 5-HT1AR and 5-HT7R are associated with the development of anxiety, depression and cognitive function linked to mechanisms of emotional learning and memory. In rodents fear conditioning and passive avoidance (PA) are associative learning paradigms to study emotional memory. This review assesses the role of 5-HT1AR and 5-HT7R as well as their interplay at the molecular, neurochemical and behavioral level. Activation of postsynaptic 5-HT1ARs impairs emotional memory through attenuation of neuronal activity, whereas presynaptic 5-HT1AR activation reduces 5-HT release and exerts pro-cognitive effects on PA retention. Antagonism of the 5-HT1AR facilitates memory retention possibly via 5-HT7R activation and evidence is provided that 5HT7R can facilitate emotional memory upon reduced 5-HT1AR transmission. These findings highlight the differential role of these 5-HTRs in cognitive/emotional domains of behavior. Moreover, the results indicate that tonic and phasic 5-HT release can exert different and potentially opposing effects on emotional memory, depending on the states of 5-HT1ARs and 5-HT7Rs and their interaction. Consequently, individual differences due to genetic and/or epigenetic mechanisms play an essential role for the responsiveness to drug treatment, e.g., by SSRIs which increase intrasynaptic 5-HT levels thereby activating multiple pre- and postsynaptic 5-HTR subtypes. PMID:26300776

  5. Anxiolytic actions of the substance P (NK1) receptor antagonist L-760735 and the 5-HT1A agonist 8-OH-DPAT in the social interaction test in gerbils.

    PubMed

    Cheeta, S; Tucci, S; Sandhu, J; Williams, A R; Rupniak, N M; File, S E

    2001-10-12

    The gerbil social interaction test has previously detected anxiolytic effects of nicotine and diazepam. In the present study, the high affinity substance P (NK(1)) receptor antagonist L-760735 (3 mg/kg) significantly increased the time spent in social interaction, whereas its low affinity analogue L-781773 (3 mg/kg) was without effect. Diazepam (0.1 mg/kg) and the 5-HT(1A) receptor agonist 8-OH-DPAT (0.003 and 0.01 mg/kg) also increased social interaction, whereas an acute dose of the selective serotonin re-uptake inhibitor fluoxetine (10 mg/kg) decreased the time spent in social interaction. Diazepam (0.1 mg/kg) significantly increased locomotor activity, but this effect was independent of the increase in social interaction. The other drugs tested were without effect on locomotor activity. The present findings suggest that the gerbil social interaction may well provide a useful assay for detecting both anxiolytic and anxiogenic compounds, and suggests that the high affinity NK(1) receptor antagonist L-760735 may prove to be useful as an anxiolytic therapy.

  6. Actions of the prototypical 5-HT1A receptor agonist 8-OH-DPAT at human alpha2-adrenoceptors: (+)8-OH-DPAT, but not (-)8-OH-DPAT is an alpha2B subtype preferential agonist.

    PubMed

    Heusler, Peter; Rauly-Lestienne, Isabelle; Tourette, Amélie; Tardif, Stéphanie; Ailhaud, Marie-Christine; Croville, Guillaume; Cussac, Didier

    2010-08-25

    8-OH-DPAT [8-hydroxy-2-(di-n-propylamino)tetralin] is the prototypical agonist at serotonin 5-HT1A receptors; however, activity at other targets contributes to the functional effects of the compound as well. We examined the properties of 8-OH-DPAT and its enantiomers at recombinant human (h)alpha2-adrenoceptor subtypes, using a panel of radioligand binding and functional tests. In competition binding experiments using [3H]-RX821002, about 10-fold selectivity of (+)8-OH-DPAT for the halpha2B subtype (pKi about 7) over halpha2A- and halpha2C-adrenoceptors was observed. In contrast, the S(-) enantiomer of 8-OH-DPAT showed similar weak affinities for the three receptor subtypes (pKis<6). The binding affinity of (+)8-OH-DPAT at the halpha2B- and the halpha2A-adrenoceptor was found sensitive to GTPgammaS, a receptor/G protein-uncoupling agent, indicating agonist properties of the drug. Furthermore, using [35S]GTPgammaS binding determination at CHO-halpha2B or CHO-halpha2A cell membranes and G protein coupled inwardly rectifying potassium (GIRK) current recordings in Xenopus oocytes expressing halpha2B, partial agonist activity of (+)8-OH-DPAT at the respective receptors was confirmed in these two different functional assays. Potency of (+)8-OH-DPAT for stimulation of [35S]GTPgammaS incorporation was lower at the halpha2A- than at the halpha2B-adrenoceptor, consistent with binding affinities. Thus, (+)8-OH-DPAT and, as a consequence, racemic (+/-)8-OH-DPAT are partial agonists at halpha2-adrenoceptors with selectivity for the halpha2B subtype, a property that might contribute to the effects of the compound described in native systems.

  7. 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

  8. Omega-3 fatty acid deficient male rats exhibit abnormal behavioral activation in the forced swim test following chronic fluoxetine treatment: association with altered 5-HT1A and alpha2A adrenergic receptor expression.

    PubMed

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

    2014-03-01

    Omega-3 fatty acid deficiency during development leads to enduing alterations in central monoamine neurotransmission in rat brain. Here we investigated the effects of omega-3 fatty acid deficiency on behavioral and neurochemical responses to chronic fluoxetine (FLX) treatment. Male rats were fed diets with (CON, n = 34) or without (DEF, n = 30) the omega-3 fatty acid precursor alpha-linolenic acid (ALA) during peri-adolescent development (P21-P90). A subset of CON (n = 14) and DEF (n = 12) rats were administered FLX (10 mg/kg/d) through their drinking water for 30 d beginning on P60. The forced swimming test (FST) was initiated on P90, and regional brain mRNA markers of serotonin and noradrenaline neurotransmission were determined. Dietary ALA depletion led to significant reductions in frontal cortex docosahexaenoic acid (DHA, 22:6n-3) composition in DEF (-26%, p = 0.0001) and DEF + FLX (-32%, p = 0.0001) rats. Plasma FLX and norfluoxetine concentrations did not different between FLX-treated DEF and CON rats. During the 15-min FST pretest, DEF + FLX rats exhibited significantly greater climbing behavior compared with CON + FLX rats. During the 5-min test trial, FLX treatment reduced immobility and increased swimming in CON and DEF rats, and only DEF + FLX rats exhibited significant elevations in climbing behavior. DEF + FLX rats exhibited greater midbrain, and lower frontal cortex, 5-HT1A mRNA expression compared with all groups including CON + FLX rats. DEF + FLX rats also exhibited greater midbrain alpha2A adrenergic receptor mRNA expression which was positively correlated with climbing behavior in the FST. These preclinical data demonstrate that low omega-3 fatty acid status leads to abnormal behavioral and neurochemical responses to chronic FLX treatment in male rats.

  9. Descending Control of Itch Transmission by the Serotonergic System via 5-HT1A-Facilitated GRP-GRPR Signaling

    PubMed Central

    Zhao, Zhong-Qiu; Liu, Xian-Yu; Jeffry, Joseph; Karunarathne, W.K. Ajith; Li, Jin-Lian; Munanairi, Admire; Zhou, Xuan-Yi; Li, Hui; Sun, Yan-Gang; Wan, Li; Wu, Zhen-Yu; Kim, Seungil; Huo, Fu-Quan; Mo, Ping; Barry, Devin M; Zhang, Chun-Kui; Kim, Ji-Young; Gautam, N.; Renner, Kenneth J.; Li, Yun-Qing; Chen, Zhou-Feng

    2014-01-01

    SUMMARY Central serotonin (5-HT) modulates somatosensory transduction, but how it achieves sensory modality-specific modulation remains unclear. Here we report that enhancing serotonergic tone via administration of 5-hydroxytryptophan potentiates itch sensation, whereas mice lacking 5-HT or serotonergic neurons in the brainstem exhibit markedly reduced scratching behavior. Through pharmacological and behavioral screening, we identified 5-HT1A as a key receptor in facilitating gastrin-releasing peptide (GRP)-dependent scratching behavior. Co-activation of 5-HT1A and GRP receptors (GRPR) greatly potentiates subthreshold, GRP-induced Ca2+ transients and action potential firing of GRPR+ neurons. Immunostaining, biochemical and biophysical studies suggest that 5-HT1A and GRPR may function as receptor heteromeric complexes. Furthermore, 5-HT1A blockade significantly attenuates, whereas its activation contributes to, long-lasting itch transmission. Thus, our studies demonstrate that the descending 5-HT system facilitates GRP-GRPR signaling via 5-HT1A to augment itch-specific outputs and a disruption of crosstalk between 5-HT1A and GRPR may be a useful anti-pruritic strategy. PMID:25453842

  10. Modulatory effect of the 5-HT1A agonist buspirone and the mixed non-hallucinogenic 5-HT1A/2A agonist ergotamine on psilocybin-induced psychedelic experience.

    PubMed

    Pokorny, Thomas; Preller, Katrin H; Kraehenmann, Rainer; Vollenweider, Franz X

    2016-04-01

    The mixed serotonin (5-HT) 1A/2A/2B/2C/6/7 receptor agonist psilocybin dose-dependently induces an altered state of consciousness (ASC) that is characterized by changes in sensory perception, mood, thought, and the sense of self. The psychological effects of psilocybin are primarily mediated by 5-HT2A receptor activation. However, accumulating evidence suggests that 5-HT1A or an interaction between 5-HT1A and 5-HT2A receptors may contribute to the overall effects of psilocybin. Therefore, we used a double-blind, counterbalanced, within-subject design to investigate the modulatory effects of the partial 5-HT1A agonist buspirone (20mg p.o.) and the non-hallucinogenic 5-HT2A/1A agonist ergotamine (3mg p.o.) on psilocybin-induced (170 µg/kg p.o.) psychological effects in two groups (n=19, n=17) of healthy human subjects. Psychological effects were assessed using the Altered State of Consciousness (5D-ASC) rating scale. Buspirone significantly reduced the 5D-ASC main scale score for Visionary Restructuralization (VR) (p<0.001), which was mostly driven by a reduction of the VR item cluster scores for elementary and complex visual hallucinations. Further, buspirone also reduced the main scale score for Oceanic Boundlessness (OB) including derealisation and depersonalisation phenomena at a trend level (p=0.062), whereas ergotamine did not show any effects on the psilocybin-induced 5D-ASC main scale scores. The present finding demonstrates that buspirone exerts inhibitory effects on psilocybin-induced effects, presumably via 5-HT1A receptor activation, an interaction between 5-HT1A and 5-HT2A receptors, or both. The data suggest that the modulation of 5-HT1A receptor activity may be a useful target in the treatment of visual hallucinations in different psychiatric and neurological diseases. PMID:26875114

  11. Modulatory effect of the 5-HT1A agonist buspirone and the mixed non-hallucinogenic 5-HT1A/2A agonist ergotamine on psilocybin-induced psychedelic experience.

    PubMed

    Pokorny, Thomas; Preller, Katrin H; Kraehenmann, Rainer; Vollenweider, Franz X

    2016-04-01

    The mixed serotonin (5-HT) 1A/2A/2B/2C/6/7 receptor agonist psilocybin dose-dependently induces an altered state of consciousness (ASC) that is characterized by changes in sensory perception, mood, thought, and the sense of self. The psychological effects of psilocybin are primarily mediated by 5-HT2A receptor activation. However, accumulating evidence suggests that 5-HT1A or an interaction between 5-HT1A and 5-HT2A receptors may contribute to the overall effects of psilocybin. Therefore, we used a double-blind, counterbalanced, within-subject design to investigate the modulatory effects of the partial 5-HT1A agonist buspirone (20mg p.o.) and the non-hallucinogenic 5-HT2A/1A agonist ergotamine (3mg p.o.) on psilocybin-induced (170 µg/kg p.o.) psychological effects in two groups (n=19, n=17) of healthy human subjects. Psychological effects were assessed using the Altered State of Consciousness (5D-ASC) rating scale. Buspirone significantly reduced the 5D-ASC main scale score for Visionary Restructuralization (VR) (p<0.001), which was mostly driven by a reduction of the VR item cluster scores for elementary and complex visual hallucinations. Further, buspirone also reduced the main scale score for Oceanic Boundlessness (OB) including derealisation and depersonalisation phenomena at a trend level (p=0.062), whereas ergotamine did not show any effects on the psilocybin-induced 5D-ASC main scale scores. The present finding demonstrates that buspirone exerts inhibitory effects on psilocybin-induced effects, presumably via 5-HT1A receptor activation, an interaction between 5-HT1A and 5-HT2A receptors, or both. The data suggest that the modulation of 5-HT1A receptor activity may be a useful target in the treatment of visual hallucinations in different psychiatric and neurological diseases.

  12. Variability in the benzodiazepine response of serotonin 5-HT1A receptor null mice displaying anxiety-like phenotype: evidence for genetic modifiers in the 5-HT-mediated regulation of GABA(A) receptors.

    PubMed

    Bailey, Sarah J; Toth, Miklos

    2004-07-14

    Benzodiazepines (BZs) acting as modulators of GABA(A) receptors (GABA(A)Rs) are an important group of drugs for the treatment of anxiety disorders. However, a large inter-individual variation in BZ sensitivity occurs in the human population with some anxiety disorder patients exhibiting diminished sensitivity to BZ and reduced density of GABA(A)Rs. The mechanism underlying BZ treatment resistance is not known, and it is not possible to predict whether an anxiety patient will respond to BZ. 5-hydroxytryptamine1A receptor (5-HT1AR) null mice (R-/-) on the Swiss-Webster (SW) background reproduce several features of BZ-resistant anxiety; they exhibit anxiety-related behaviors, do not respond to BZ, have reduced BZ binding, and have decreased expression of the major GABA(A)R subunits alpha1 and alpha2. Here, we show that R-/- mice on the C57Bl6 (B6) background also have anxiety phenotype, but they respond to BZ and have normal GABA(A)R subunit expression. This indicates that the 5-HT1AR-mediated regulation of GABA(A)R alpha subunit expression is subject to genetic modification. Hybrid SW/B6-R-/- mice also exhibit BZ-resistant anxiety, suggesting that SW mice carry a genetic modifier, which mediates the effect of the 5-HT1AR on the expression of GABA(A)Ralpha subunits. In addition, we show that this genetic interaction in SW mice operates early in postnatal life to influence the expression of GABA(A)R alpha subunits at the transcriptional level. These data indicate that BZ-resistant anxiety results from a developmental arrest of GABA(A)R expression in SW-R-/- mice, and a similar mechanism may be responsible for the BZ insensitivity of some anxiety patients.

  13. Pharmacological, neurochemical, and behavioral profile of JB-788, a new 5-HT1A agonist.

    PubMed

    Picard, M; Morisset, S; Cloix, J F; Bizot, J C; Guerin, M; Beneteau, V; Guillaumet, G; Hevor, T K

    2010-09-01

    A novel pyridine derivative, 8-{4-[(6-methoxy-2,3-dihydro-[1,4]dioxino[2,3-b]pyridine-3-ylmethyl)-amino]-butyl}-8-aza-spiro[4.5]decane-7,9-dione hydrochloride, termed JB-788, was designed to selectively target 5-HT(1A) receptors. In the present study, the pharmacological profile of JB-788 was characterized in vitro using radioligands binding tests and in vivo using neurochemical and behavioural experiments. JB-788 bound tightly to human 5-HT(1A) receptor expressed in human embryonic kidney 293 (HEK-293) cells with a K(i) value of 0.8 nM. Its binding affinity is in the same range as that observed for the (+/-)8-OH-DPAT, a reference 5HT(1A) agonist compound. Notably, JB-788 only bound weakly to 5-HT(1B) or 5-HT(2A) receptors and moreover the drug displayed only weak or indetectable binding to muscarinic, alpha(2), beta(1) and beta(2) adrenergic receptors, or dopaminergic D(1) receptors. JB-788 was found to display substantial binding affinity for dopaminergic D(2) receptors and, to a lesser extend to alpha(1) adrenoreceptors. JB-788 dose-dependently decreased forskolin-induced cAMP accumulation in HEK cells expressing human 5-HT(1A), thus acting as a potent 5-HT(1A) receptor agonist (E(max.) 75%, EC(50) 3.5 nM). JB-788 did not exhibit any D(2) receptor agonism but progressively inhibited the effects of quinpirole, a D(2) receptor agonist, in the cAMP accumulation test with a K(i) value of 250 nM. JB-788 induced a weak change in cAMP levels in mouse brain but, like some antipsychotics, transiently increased glycogen contents in various brain regions. Behavioral effects were investigated in mice using the elevated plus-maze. JB-788 was found to increase the time duration spent by animals in anxiogenic situations. Locomotor hyperactivity induced by methamphetamine in mouse, a model of antipsychotic activity, was dose-dependently inhibited by JB-788. Altogether, these results suggest that JB-788 displays pharmacological properties, which could be of interest in the area

  14. 5-HT1A Agonist Properties Contribute to a Robust Response to Vilazodone in the Novelty Suppressed Feeding Paradigm

    PubMed Central

    Garcia-Garcia, Alvaro L.; Navarro-Sobrino, Míriam; Pilosof, Gila; Banerjee, Pradeep; Dranovsky, Alex

    2016-01-01

    Background: Differences in 5-HT1A receptor function have been implicated in vulnerability to depression and in response to treatment. Adding 5-HT1A partial agonists to selective serotonin reuptake inhibitors has been touted as a strategy to increase their efficacy. Here we use the novelty suppressed feeding paradigm to compare the effects of vilazodone, a high-potency selective serotonin reuptake inhibitor, with high affinity for 5-HT1A receptors to the reference selective serotonin reuptake inhibitor fluoxetine across several mouse strains that differ in their response to selective serotonin reuptake inhibitors. Methods: To confirm 5-HT1A agonist activity, body temperature was measured after acute administration of vilazodone or fluoxetine, as administration of 5-HT1A agonists induces hypothermia. We next used 3 strains of mice to examine the effects of the drugs on latency in the novelty suppressed feeding, a paradigm generally sensitive to chronic but not acute effects of antidepressants. Results: Vilazodone induces robust hypothermia and blocks stress-induced hyperthermia in a 5-HT1A-dependent manner, consistent with agonist effects at 5-HT1A autoreceptors. In 129SvEv mice, vilazodone (10mg/kg/d) reduces the latency to eat in the novelty suppressed feeding test within 8 days, while no effect of fluoxetine (20mg/kg/d) was detected at that time. In contrast, both vilazodone and fluoxetine are effective at decreasing latency to eat in the novelty suppressed feeding paradigm in a strain with low autoreceptor levels. In mice with higher autoreceptor levels, no significant difference was detected between fluoxetine and vehicle (P=.8) or vilazodone and vehicle (P=.06). Conclusion: In mice, vilazodone may offer advantages in time of onset and efficacy over a reference selective serotonin reuptake inhibitor in the novelty suppressed feeding test. PMID:27352617

  15. Rat dams exposed repeatedly to a daily brief separation from the pups exhibit increased maternal behavior, decreased anxiety and altered levels of receptors for estrogens (ERα, ERβ), oxytocin and serotonin (5-HT1A) in their brain.

    PubMed

    Stamatakis, Antonios; Kalpachidou, Theodora; Raftogianni, Androniki; Zografou, Efstratia; Tzanou, Athanasia; Pondiki, Stavroula; Stylianopoulou, Fotini

    2015-02-01

    In the present study we investigated the neurobiological mechanisms underlying expression of maternal behavior. Increased maternal behavior was experimentally induced by a brief 15-min separation between the mother and the pups during postnatal days 1 to 22. On postnatal days (PND) 12 and 22, we determined in experimental and control dams levels of anxiety in the elevated plus maze (EPM) as well as the levels of receptors for estrogens (ERα, ERβ), oxytocin (OTR) and serotonin (5-HT1AR) in areas of the limbic system (prefrontal cortex-PFC, hippocampus, lateral septum-SL, medial preoptic area-MPOA, shell of nucleus accumbens-nAc-Sh, central-CeA and basolateral-BLA amygdala), involved in the regulation of maternal behavior. Experimental dams, which showed increased maternal behavior towards their offspring, displayed reduced anxiety in the EPM on both PND12 and PND22. These behavioral differences could be attributed to neurochemical alterations in their brain: On both PND12 and PND22, experimental mothers had higher levels of ERα and OTRs in the PFC, hippocampus, CeA, SL, MPOA and nAc-Sh. The experimental manipulation-induced increase in ERβ levels was less widespread, being localized in PFC, the hippocampal CA2 area, MPOA and nAc-Sh. In addition, 5-HT1ARs were reduced in the PFC, hippocampus, CeA, MPOA and nAc-Sh of the experimental mothers. Our results show that the experience of the daily repeated brief separation from the pups results in increased brain ERs and OTRs, as well as decreased 5-HT1ARs in the dam's brain; these neurochemical changes could underlie the observed increase in maternal behavior and the reduction of anxiety.

  16. Pharmacological profiles in rats of novel antipsychotics with combined dopamine D2/serotonin 5-HT1A activity: comparison with typical and atypical conventional antipsychotics.

    PubMed

    Bardin, Laurent; Auclair, Agnès; Kleven, Mark S; Prinssen, Eric P M; Koek, Wouter; Newman-Tancredi, Adrian; Depoortère, Ronan

    2007-03-01

    Combining antagonist/partial agonist activity at dopamine D2 and agonist activity at serotonin 5-HT1A receptors is one of the approaches that has recently been chosen to develop new generation antipsychotics, including bifeprunox, SSR181507 and SLV313. There have been, however, few comparative data on their pharmacological profiles. Here, we have directly compared a wide array of these novel dopamine D2/5-HT1A and conventional antipsychotics in rat models predictive of antipsychotic activity. Potency of antipsychotics to antagonize conditioned avoidance, methylphenidate-induced behaviour and D-amphetamine-induced hyperlocomotion correlated with their affinity at dopamine D2 receptors. Potency against ketamine-induced hyperlocomotion was independent of affinity at dopamine D2 or 5-HT1A receptors. Propensity to induce catalepsy, predictive of occurrence of extrapyramidal side effects, was inversely related to affinity at 5-HT1A receptors. As a result, preferential D2/5-HT1A antipsychotics displayed a large separation between doses producing 'antipsychotic-like' vs. cataleptogenic actions. These data support the contention that 5-HT1A receptor activation greatly reduces or prevents the cataleptogenic potential of novel antipsychotics. They also emphasize that interactions at 5-HT1A and D2 receptors, and the nature of effects (antagonism or partial agonism) at the latter has a profound influence on pharmacological activities, and is likely to affect therapeutic profiles.

  17. Investigating the Motivational Mechanism of Altered Saline Consumption Following 5-HT1A Manipulation

    PubMed Central

    Caras, Melissa L.; MacKenzie, Kimberly; Rodwin, Benjamin; Katz, Donald B.

    2010-01-01

    The precise role played by serotonin (5-HT) in taste—an issue of great interest given the involvement of serotonin in human sensory and eating disorders—is a matter of considerable debate, perhaps because of the variety of methodologies that have been brought to bear by different researchers. Here, we use multiple methods to reveal the motivational mechanism whereby 5-HT1A receptor activation modulates drinking behavior. Subcutaneous injections of the selective 5-HT1A agonist 8-hydroxy-2-di-n-propylamino-tetralin (8-OH-DPAT), a drug that reduces 5-HT release by acting on presynaptic auto-receptors, dose-dependently increased consumption of 0.45M NaCl in a one-bottle test. In a two-bottle test, however, 8-OH-DPAT-treated animals (30 μg/kg/ml) demonstrated decreased NaCl preference—although our detection of this effect was obscured by adaptation to the drug across days. Rats’ performance in a brief access test confirmed that 8-OH-DPAT decreased preference for saline by both increasing water consumption and decreasing NaCl consumption. Finally, taste reactivity tests demonstrated that the latter result does not reflect decreased NaCl palatability. Overall, the results suggest that 8-OH-DPAT-induced 5-HT hypofunction increases thirst without substantially affecting the palatability of NaCl. PMID:18410179

  18. Electrophysiological responses of serotoninergic dorsal raphe neurons to 5-HT1A and 5-HT1B agonists.

    PubMed

    Sprouse, J S; Aghajanian, G K

    1987-01-01

    A direct comparison was made of the effects of serotonin 5-HT1A and 5-HT1B selective compounds on the spontaneous firing rate of dorsal raphe serotoninergic neurons in chloral-hydrate-anesthetized rats. Following intravenous administration, the 5-HT1A selective compounds ipsapirone (TVX Q 7821) and LY 165163 potently inhibited single-unit activity in a dose-dependent manner whereas the 5-HT1B selective compounds, m-chlorophenylpiperazine (mCPP) and trifluoromethylphenylpiperazine (TFMPP), displayed only weak or irregular actions. Low microiontophoretic currents of ipsapirone and LY 165163 were also effective in suppressing spontaneous firing; dose-response relationships for the 5-HT1A compounds were indistinguishable from that of 5-HT itself. In contrast, dorsal raphe neurons were only weakly responsive to microiontophoretic application of mCPP and TFMPP; dose-response relationships for the 5-HT1B compounds were significantly displaced from that of 5-HT. In intracellular studies, ipsapirone and LY 165163, when added to the media bathing brain slices, mimicked the actions of 5-HT in hyperpolarizing dorsal raphe cell membranes and decreasing input resistance; however, the maximal effects of the 5-HT1A compounds on these membrane properties exceeded those of 5-HT. In summary, dorsal raphe 5-HT neurons appear highly responsive to 5-HT1A, but not to 5-HT1B compounds; these findings are discussed with regard to the 5-HT receptor subtypes as candidates for the somatodendritic autoreceptor of dorsal raphe neurons. PMID:3505364

  19. Yohimbine is a 5-HT1A agonist in rats in doses exceeding 1 mg/kg

    PubMed Central

    Zaretsky, Dmitry V.; Zaretskaia, Maria V.; DiMicco, Joseph A.; Rusyniak, Daniel E.

    2015-01-01

    Yohimbine is a prototypical alpha2-adrenergic receptor antagonist. Due to its relatively high selectivity, yohimbine is often used in experiments whose purpose is to examine the role of these receptors. For example, yohimbine has been employed at doses of 1–5 mg/kg to reinstate drug-seeking behavior after extinction or to antagonize general anesthesia, an effects presumably being a consequence of blocking alpha2-adrenergic receptors. In this report we characterized dose-dependent autonomic and behavioral effects of yohimbine and its interaction with an antagonist of 5-HT1A receptors, WAY 100635. In low doses (0.5 – 2 mg/kg i.p.) yohimbine induced locomotor activation which was accompanied by a tachycardia and mild hypertension. Increasing the dose to 3–4.5 mg/kg reversed the hypertension and locomotor activation and induced profound hypothermia. The hypothermia as well as the suppression of the locomotion and the hypertension could be reversed by the blockade of 5-HT1A receptors with WAY 100635. Our data confirm that yohimbine possesses 5-HT1A properties, and demonstrated that in doses above 1 mg/kg significantly activate these receptors. PMID:26366943

  20. Influence of light cycle on response to 5-HT1A ligands in punished responding in rats.

    PubMed

    Gleason, S D; Leander, J D

    1999-12-01

    Since the introduction of buspirone, the 5-HT1A receptor has been a focal point for serotonergic research into the treatment of anxiety. Two of the more commonly used methodologies for evaluating potential anxiolytics are the Geller-Seifter model and the elevated plus maze. In the Geller-Seifter model, administration of 5-HT1A agonists produce an anxiolytic-like profile consisting of an increase in the number of responses made during the punished component. An anxiolytic-like response in the elevated plus maze consists of an increase in the number of entries and/or time spent in the open arms of the maze. Recently, there have been reports of differential drug effects with 5-HT1A ligands in the elevated plus maze depending on when in the diurnal cycle the 5-HT1A agents were administered. The purpose of the current study was to characterize the response to 5-HT1A compounds in normal and reverse light cycle animals in the Geller-Seifter model. 8-OH-DPAT [(+/-)-2-dipropylamino-8-hydroxy-1,2,3,4-tetrahydronapthalene] produced a decrease in unpunished responding and an increase in punished responding during both the light and dark phase. The administration of WAY 100,635 [N-¿2-[4-(2-methoxyphenyl)-1-piperazinyl] ethyl¿-N-(2-pyridinyl)cyclohexanecarboxamide trihydrochloridel alone was without effect in both the light and dark phase. Furthermore, pre-treatment with WAY 100,635 completely antagonized both the rate-decreasing effects in the unpunished component and the increase in punished responding observed with 8-OH-DPAT during both the light and dark phase. The results of the current study diverge from previous findings of sensitivity to the diurnal cycle in other models reflective of modulation of the 5-HT1A receptor. The robustness of the response, in this case punished lever pressing, may be less sensitive than other more naturalistic or ethological methods (i.e. elevated plus maze) in detecting the subtle changes in receptor function due to the diurnal cycle. PMID

  1. The 5-HT1A antagonist, WAY 100 635, alleviates cognitive impairments induced by dizocilpine (MK-801) in monkeys.

    PubMed

    Harder, J A; Ridley, R M

    2000-02-14

    Central glutamate neurotransmission is modulated by an upregulatory cholinergic influence and an inhibitory serotonergic influence. In Alzheimer's disease, cognitive decline is associated with loss of both glutamatergic and cholinergic neurones (Francis et al., 1992, Progress in Neurobiology 39, 517-545). While therapeutic strategies for alleviating this cognitive decline have concentrated on restoring cholinergic tone, we suggest that 5-HT1A antagonists also have the potential to alleviate the cognitive symptoms of Alzheimer's disease. Previous studies have shown that dizocilpine (MK-801), a glutamatergic antagonist acting at the NMDA receptor, produces learning impairments in the common marmoset, a non-human primate. Specifically, it impairs the acquisition of shape discrimination and visuospatial conditional tasks, at doses that do not affect locomotor behaviour or coordination (Harder et al., 1998, Society for Neuroscience Abstracts 23(1), 219). In the present study we investigated the effects of WAY 100 635, a 5-HT1A antagonist, on the cognitive deficits induced by dizocilpine. The number of trials required to learn each type of task under combined treatment with dizocilpine and WAY 100 635 was significantly lower than under dizocilpine treatment alone, and did not differ significantly from the number of trials required under saline, demonstrating that the cognitive effects of glutamatergic blockade can be overcome by treatment with a 5-HT1A antagonist.

  2. 17β-estradiol-induced regulation of the novel 5-HT1A-related transcription factors NUDR and Freud-1 in SH SY5Y cells.

    PubMed

    Adeosun, Samuel O; Albert, Paul R; Austin, Mark C; Iyo, Abiye H

    2012-05-01

    Nuclear deformed epidermal autoregulatory factor-1 (NUDR/Deaf-1) and five prime repressor element under dual repression (Freud-1) are novel transcriptional regulators of the 5-HT(1A) receptor, a receptor that has been implicated in the pathophysiology of various psychiatric illnesses. The antidepressant effect of 17β-Estradiol (17βE(2)) is purported to involve the downregulation of this receptor. We investigated the possible role of NUDR and Freud-1 in 17βE(2)-induced downregulation of the 5-HT(1A) receptor in the neuroblastoma cell line SH SY5Y. Cells were treated with 10 nM of 17βE(2) for 3 or 48 h, followed by a 24-h withdrawal period. Proteins were isolated and analyzed by western blotting. 17βE(2) treatment increased NUDR immunoreactivity while Freud-1 and the 5-HT(1A) receptor showed significant decreases. Upon withdrawal of 17βE(2), protein expression returned to control levels, except for NUDR, which remained significantly elevated in the 3-h treatment. Taken together, these data support a non-genomic downregulation of 5-HT(1A) receptor protein by 17βE(2), which does not involve NUDR and Freud-1. Rather, changes in both transcription factors seem to be compensatory/homeostatic responses to changes in 5-HT(1A) receptor induced by 17βE(2). These observations further highlight the importance of NUDR and Freud-1 in regulating 5-HT(1A) receptor expression.

  3. Mass screening of rare 5HT1A variants using ECL detection

    SciTech Connect

    Bergen, A.; Wang, C.Y.; Nakhai, B.

    1994-09-01

    We are using electrochemiluminescence (ECL) detection technology to screen a large collection of patient DNAs (approximately 4000) arranged in pooled arrays for two rare amino acid substitutions in the 5HT1A serotonin receptor gene. The nucleotide changes are G746A (G22S) and A765G (128V). Conversion of two SSCP variants to allele-specific amplification (ASA) polymorphisms was accomplished and ECL detection enabled with the chemical addition of biotin and tris-bipyridyl ruthenium chelate to 5{prime} (specific) and 3{prime} (non-specific) oligonucleotide PCR primers, respectively. Pooling experiments indicate that the ASA-PCR is sensitive enough to reproducibily amplify the polymorphic allele from as little as 2 ng of genomic DNA in the presence of a 50-fold excess of genomic DNA from individuals negative for the polymorphic allele. ECL detection of specific PCR products indicates that the ECL device being used provides two logs of electrochemiluminescent discrimination between {open_quotes}positive{close_quotes} and {open_quotes}negative{close_quotes} PCR reactions. SSCP screening and ECL detection methods are being performed on approximately one-tenth of the collection to validate the ECL method. The detection sensitivity of the ECL device and the design of the pooled DNA arrays will reduce the number of PCRs required to detect these rare polymorphisms to 10% of that required with conventional screening techniques.

  4. Identification of dual active agents targeting 5-HT1A and SERT by combinatorial virtual screening methods.

    PubMed

    Wang, Panpan; Yang, Fengyuan; Yang, Hong; Xu, Xiaofei; Liu, Duo; Xue, Weiwei; Zhu, Feng

    2015-01-01

    Selective serotonin reuptake inhibitors (SSRIs) are most adopted therapeutics marketed for major depression, and the efficacy of which are greatly reduced by their delayed onset of action and undesirable side effects. 5-HT1A receptor partial agonist and SERT inhibitor (SPARI) was proposed as a novel strategy to overcome the shortage of efficacy by a negative feedback control of 5-HT1A receptor. However, only one SPARI (vilazodone) has been approved for clinical use, and none is currently in clinical trial, which demonstrates a strong need for searching more novel SPARIs to facilitate antidepressants discovery. This work applied a combinatorial virtual screening method (CVSM) by integrating multiple tools. Statistic analysis reveals that CVSM surpasses single virtual screening methods in terms of hit rates and enrichment factors. By adopting optimized CVSM, 91 promising dual target leads form 15 scaffolds were identified, and 40% of these scaffolds have already been reported to show antidepressant related therapeutic effects. In sum, CVSM is capable in identifying novel SPARIs from large chemical libraries with extremely low false hit rate. PMID:26406003

  5. Enhancement of the FGFR1 signaling in the FGFR1-5-HT1A heteroreceptor complex in midbrain raphe 5-HT neuron systems. Relevance for neuroplasticity and depression.

    PubMed

    Borroto-Escuela, Dasiel O; Pérez-Alea, Mileidys; Narvaez, Manuel; Tarakanov, Alexander O; Mudó, Giuseppa; Jiménez-Beristain, Antonio; Agnati, Luigi F; Ciruela, Francisco; Belluardo, Natale; Fuxe, Kjell

    2015-07-31

    New findings show existence of FGFR1-5-HT1A heteroreceptor complexes in 5-HT nerve cells of the dorsal and median raphe nuclei of the rat midbrain and hippocampus. Synergistic receptor-receptor interactions in these receptor complexes indicated their enhancing role in hippocampal plasticity. The existence of FGFR1-5-HT1A heteroreceptor complexes also in midbrain raphe 5-HT nerve cells open up the possibility that antidepressant drugs by increasing extracellular 5-HT levels can cause an activation of the FGF-2/FGFR1 mechanism in these nerve cells as well. Therefore, the agonist modulation of the FGFR1-5-HT1A heteroreceptor complexes and their specific role is now determined in rat medullary raphe RN33B cells and in the caudal midline raphe area of the midbrain rich in 5-HT nerve cells. The combined i.c.v. treatment with FGF-2 and the 5-HT1A agonist 8-OHDPAT synergistically increased FGFR1 and ERK1/2 phosphorylation in the raphe midline area of the midbrain and in the RN33B cells. Cotreatment with FGF2 and the 5-HT1A agonist induced RN33B cell differentiation as seen from development of an increased number and length of extensions per cell and their increased 5-HT immunoreactivity. These signaling and differentiation events were dependent on the receptor interface since they were blocked by incubation with TMV but not by TMII of the 5-HT1A receptor. Taken together, the 5-HT1A autoreceptors by being part of a FGFR1-5-HT1A heteroreceptor complex in the midbrain raphe 5-HT nerve cells appears to have also a trophic role in the central 5-HT neuron systems besides playing a key role in reducing the firing of these neurons.

  6. Predictive comparative QSAR modelling of (phenylpiperazinyl-alkyl) oxindoles as selective 5-HT1A antagonists by stepwise regression, PCRA, FA-MLR and PLS techniques.

    PubMed

    Adhikari, Nilanjan; Maiti, Milan K; Jha, Tarun

    2010-03-01

    5-Hydroxytryptamine, a neurotransmitter released by 5-HT neurons in raphe nuclei and 5-HT(1A) receptors are involved in the pain mechanism of migraine, prevention of postpartum haemorrhage, CNS effects like sleep, anxiety and thermoregulation. Comparative QSAR study was done on thirtytwo (phenylpiperazinyl-alkyl) oxindoles using stepwise regression, PCRA, FA-MLR and PLS techniques to find structurally significant models. ETSA indices at atom numbers 19, 20 and 22, RTSA indices at atom numbers 6, 10 and 20, charge at atom number 19 and presence of chlorine at the atom number 6 may be conducive for the receptor inhibition. Electrophilic attack at atom number 21 may be unfavourable but nucleophilic attack at atom numbers 8 and 14 may be beneficial for % 5-HT(1A) inhibition.

  7. Linear and Nonlinear Support Vector Machine for the Classification of Human 5-HT1A Ligand Functionality.

    PubMed

    Wang, Lirong; Ma, Chao; Wipf, Peter; Xie, Xiang-Qun

    2012-01-01

    Upon binding to a receptor, agonists and antagonists can induce distinct biological functions and thus lead to significantly different pharmacological responses. Thus, in silico prediction or in vitro characterization of ligand agonistic or antagonistic functionalities is an important step toward identifying specific pharmacological therapeutics. In this study, we investigated the molecular properties of agonists and antagonists of human 5-hydroxytryptamine receptor subtype 1A (5-HT1A ). Subsequently, intrinsic functions of these ligands (agonists/antagonists) were modeled by support vector machine (SVM), using five 2D molecular fingerprints and the 3D Topomer distance. Five kernel functions, including linear, polynomial, RBF, Tanimoto and a novel Topomer kernel based on Topomer 3D similarity were used to develop linear and nonlinear classifiers. These classifiers were validated through cross-validation, yielding a classification accuracy ranging from 80.4 % to 92.3 %. The performance of different kernels and fingerprints was analyzed and discussed. Linear and nonlinear models were further interpreted through the illustration of underlying classification mechanism. The computation protocol has been automated and demonstrated through our online service. This study expands the scope and applicability of similarity-based methods in cheminformatics, which are typically used for the identification of active molecules against a target protein. Our findings provide a good starting point for further systematic classifications of other GPCR ligands and for the data mining of large chemical libraries.

  8. Clonidine potentiates the effects of 5-HT1A, 5-HT1B and 5-HT2A/2C antagonists and 8-OH-DPAT in the mouse forced swimming test.

    PubMed

    Redrobe, J P; Bourin, M

    1998-08-01

    The present study was undertaken to identify the receptor subtypes involved in clonidine's ability to enhance the effects of antidepressant drugs in the mouse forced swimming test. Clonidine (0.06 mg/kg, i.p.) significantly enhanced the antidepressant-like effects of subactive doses of the 5-HT1A receptor agonist, 8-OH-DPAT (1 mg/kg, i.p.; P<0.01); the 5-HT1A receptor antagonist, NAN 190 (0.5 mg/kg, i.p.; P<0.01); the 5-HT1A/1B autoreceptor antagonist, (+/-) pindolol (32 mg/kg, i.p.; P<0.01); the 5-HT2A/2C receptor antagonist, ritanserin (4 mg/kg, i.p.; P<0.01). Pretreatment with clonidine failed to increase mobility when administered in combination with the 5-HT1B receptor agonist, RU 24969 (1 mg/kg, i.p.) or the 5-HT2A receptor antagonist, ketanserin (8 mg/kg, i.p.). In conclusion, clonidine-induced anti-immobility effects are more likely mediated by 5-HT1A and 5-HT2C receptors, as well as alpha-2-adrenergic autoreceptors situated on noradrenergic neurones. The results of the present study also demonstrate that serotonergic receptor function can influence alpha-2-adrenoreceptor mediated responses in the mouse forced swimming test.

  9. The association between romantic relationship status and 5-HT1A gene in young adults.

    PubMed

    Liu, Jinting; Gong, Pingyuan; Zhou, Xiaolin

    2014-01-01

    What factors determine whether or not a young adult will fall in love? Sociological surveys and psychological studies have shown that non-genetic factors, such as socioeconomic status, external appearance, and personality attributes, are crucial components in romantic relationship formation. Here we demonstrate that genetic variants also contribute to romantic relationship formation. As love-related behaviors are associated with serotonin levels in the brain, this study investigated to what extent a polymorphism (C-1019G, rs6295) of 5-HT1A gene is related to relationship status in 579 Chinese Han people. We found that 50.4% of individuals with the CC genotype and 39.0% with CG/GG genotype were in romantic relationship. Logistic regression analysis indicated that the C-1019G polymorphism was significantly associated with the odds of being single both before and after controlling for socioeconomic status, external appearance, religious beliefs, parenting style, and depressive symptoms. These findings provide, for the first time, direct evidence for the genetic contribution to romantic relationship formation. PMID:25412229

  10. Screening of medicinal plants from Suriname for 5-HT(1A) ligands: Bioactive isoquinoline alkaloids from the fruit of Annona muricata.

    PubMed

    Hasrat, J A; Pieters, L; De Backer, J P; Vauquelin, G; Vlietinck, A J

    1997-06-01

    Plants from Suriname (South-America) and several Annona species, including A. muricata, A. ckerimolia, A. montana and A. glabra were screened for 5-HT(1A) receptor binding activity by ligand-binding-studies (LBS). Crude extracts of all Annona species and from Hibiscus bifurcatus, Irlbarchia purpurascens and Scoparia dulcis showed high activity. The isoquinoline alkaloids asimilobine (1), nornuciferine (2), and annonaine (3) were isolated as the active principles from the fruit of Annona muricata. These results may partially explain the use of Hibiscus bifurcatus and Annona muricata in traditional medicine in Suriname.

  11. Additive effect of lithium and clonidine with 5-HT1A agonists in the forced swimming test.

    PubMed

    Hascoet, M; Bourin, M; Khimake, S

    1994-03-01

    1. The aim of the present work was to demonstrate the possible additive effect of lithium and clonidine with 5-HT1a agonists in the forced swimming test. 2. Anti-depressant like effects of 5-HT1a agonists was investigated using forced swimming test. When administered alone, only 8-OH-DPAT reduced the immobility time in mice. 3. 5-HT1a agonists were then tested in combination with clonidine or lithium. Only gepirone and ipsapirone pretreated by either lithium or clonidine reduced immobility time in the forced swimming test. 4. The authors conclude that lithium and clonidine might be useful to predict antidepressant-like activity of new compounds.

  12. Differences among conventional, atypical and novel putative D(2)/5-HT(1A) antipsychotics on catalepsy-associated behaviour in cynomolgus monkeys.

    PubMed

    Auclair, Agnès L; Kleven, Mark S; Barret-Grévoz, Catherine; Barreto, Martine; Newman-Tancredi, Adrian; Depoortère, Ronan

    2009-11-01

    Typical antipsychotics such as haloperidol exert their therapeutic effects via blockade of dopamine (DA) D(2) receptors, leading to extrapyramidal symptoms (EPS) in humans and catalepsy in rodents. In contrast, atypical antipsychotics and new generation D(2)/5-HT(1A) antipsychotics have low cataleptogenic potential. However, there has been no systematic comparative study on the effects of these different classes of antipsychotics in non-human primates, a species displaying a more sophisticated repertoire of behavioural/motor activity than rats. Once weekly, six young adult female non-haloperidol-sensitised cynomolgus monkeys were treated i.m. with a test compound and videotaped to score catalepsy-associated behaviour (CAB: static postures, unusual positions and crouching). Haloperidol, risperidone, olanzapine, nemonapride and remoxipride induced, to different extents, an increase in unusual positions (a response akin to dystonia), some crouching and static postures. In contrast, clozapine, quetiapine, ziprasidone and aripiprazole produced much lower or no unusual positions; clozapine also produced marked increases in static postures and crouching. Among novel D(2)/5-HT(1A) antipsychotics, SLV313 and F15063 augmented the number of unusual positions, albeit at doses 16-63 times higher than those of haloperidol for approximately the same score. SSR181507 and bifeprunox produced moderate static postures, little crouching and negligible unusual positions. These data provide the first comparative analysis in cynomolgus monkeys of EPS liability of conventional, atypical and novel D(2)/5-HT(1A) antipsychotics. They indicate that the latter are less prone than haloperidol to produce CAB, and provide a basis for comparison with rodent catalepsy studies. PMID:19464324

  13. Pharmacological Characterization of 5-HT1A Autoreceptor-Coupled GIRK Channels in Rat Dorsal Raphe 5-HT Neurons

    PubMed Central

    Montalbano, Alberto; Corradetti, Renato; Mlinar, Boris

    2015-01-01

    G protein-activated inwardly rectifying potassium (GIRK) channels in 5-HT neurons are assumed to be principal effectors of 5-hydroxytryptamine 1A (5-HT1A) autoreceptors, but their pharmacology, subunit composition and the role in regulation of 5-HT neuron activity have not been fully elucidated. We sought for a pharmacological tool for assessing the functional role of GIRK channels in 5-HT neurons by characterizing the effects of drugs known to block GIRK channels in the submicromolar range of concentrations. Whole-cell voltage-clamp recording in brainstem slices were used to determine concentration-response relationships for the selected GIRK channel blockers on 5-HT1A autoreceptor-activated inwardly rectifying K+ conductance in rat dorsal raphe 5-HT neurons. 5-HT1A autoreceptor-activated GIRK conductance was completely blocked by the nonselective inwardly rectifying potassium channels blocker Ba2+ (EC50 = 9.4 μM, full block with 100 μM) and by SCH23390 (EC50 = 1.95 μM, full block with 30 μM). GIRK-specific blocker tertiapin-Q blocked 5-HT1A autoreceptor-activated GIRK conductance with high potency (EC50 = 33.6 nM), but incompletely, i.e. ~16% of total conductance resulted to be tertiapin-Q-resistant. U73343 and SCH28080, reported to block GIRK channels with submicromolar EC50s, were essentially ineffective in 5-HT neurons. Our data show that inwardly rectifying K+ channels coupled to 5-HT1A autoreceptors display pharmacological properties generally expected for neuronal GIRK channels, but different from GIRK1-GIRK2 heteromers, the predominant form of brain GIRK channels. Distinct pharmacological properties of GIRK channels in 5-HT neurons should be explored for the development of new therapeutic agents for mood disorders. PMID:26460748

  14. The 5-HT1A C(-1019)G polymorphism, personality and electrodermal reactivity in a reward/punishment paradigm.

    PubMed

    Schmitz, Anja; Kirsch, Peter; Reuter, Martin; Alexander, Nina; Kozyra, Eva; Kuepper, Yvonne; Osinsky, Roman; Hennig, Juergen

    2009-04-01

    During past years the 5-HT(1A) C(-1019)G polymorphism has been associated with vulnerability to depression, anxiety-disorder and personality traits related to negative emotionality (e.g. neuroticism). Many of these studies focused on case-control comparisons or associations between genetic markers and personality traits assessed by the use of questionnaires. In contrast, overt behaviour and physiological measures in experimental paradigms, although very promising, have seldom been the focus of studies investigating the role of the 5-HT(1A) polymorphism for behaviour and psychopathology. To fill this gap, we examined the relationship between the 5-HT(1A) C(-1019)G polymorphism and reaction times (in a reward/punishment paradigm) as well as electrodermal activity, as a marker of autonomic arousal, in 123 healthy subjects. This paradigm seems very promising, as sensitivity to punishment in particular, is strongly associated to traits related to negative emotionality. Carriers of the GG genotype, which is related to increased expression of 5-HT(1A) autoreceptors, exhibited increased reaction times when they were able to win money (reward condition). In direct contrast to the reward condition, these subjects show faster reaction times in the punishment condition (losing money). Moreover, GG carriers are characterized by an enhanced electrodermal activity in all experimental conditions (win, lose and verbal feedback). Finally, the reaction-time pattern mentioned was related to higher scores on negative emotionality as revealed by self-reports. These findings demonstrate for the first time that the 5-HT(1A) polymorphism is related to personality on the level of a triadic approach including behaviour, physiology and self-reports. PMID:18796187

  15. Anticonflict effects of 5HT(1A) agonists in pigeons are dependent on the level of response suppression.

    PubMed

    Benvenga, M.J.; Leander, J.D.

    1996-11-01

    Anxiety is a phenomenon that has many different manifestations. In order to test whether or not agents targeted to treat anxiety may have the properties necessary to treat differing types of anxiety, we have studied a 8-OH DPAT, buspirone, LY228729, chlordiazepoxide and pentobarbital on three different punished responding procedures in pigeons. Procedure one was a fairly standard multiple FR30 FR30 punished responding model where responding into he punished component was suppressed by electric shock to 7-10% of responding in the unpunished component. Procedure two was similar except that responding during the punished component was suppressed more severely to 1-3% of control, using increased levels of shock. Procedure three was a VI30 schedule as the unpunished component, with concomitant FR5 shock in a second component, and concomitant FR20 shock in the third component. 5HT(1A) agonists, 8-OH DPAT, buspirone and LY228729 produced the typical large increases in punished responding in procedure one, were substantially less effective when shock levels were increased in procedure two, and produced differential results which were likely due to the schedule in procedure three. The more traditional anxiolytics, chlordiazepoxide and pentobarbital, were consistently effective across all three punished responding procedures. These results would seem to indicate that 5HT(1A) agonists may not be as broadly efficacious as traditional anxiolytics, and that the state or severity of anxiety may be an important variable to predict efficacy for 5HT(1A) agonists.

  16. The 5-HT1A antagonist, WAY 100635, ameliorates the cognitive impairment induced by fornix transection in the marmoset.

    PubMed

    Harder, J A; Maclean, C J; Alder, J T; Francis, P T; Ridley, R M

    1996-10-01

    Fornix transection in the marmoset produces a specific pattern of cognitive deficits, notably a lack of ability to recall visuospatial tasks learnt preoperatively, and a deficit in acquiring new visuospatial tasks following transection. Previous work has shown that this learning impairment can be ameliorated by cholinergic agonists, suggesting that it occurs as a consequence of destroying the cholinergic projection from the vertical limb of the diagonal band to the hippocampus which runs through the fornix. We have now shown that this deficit in new learning can be significantly alleviated by the 5-HT1A antagonist, WAY 100635. This result supports the suggestion that 5-HT1A projections are inhibitory on the same target cells for which cholinergic projections are excitatory, and that loss of function in the target cells caused by loss of excitatory tone can be compensated by blockade of inhibitory tone. Since cholinergic loss in the hippocampus (and neocortex) occurs in association with cognitive decline in Alzheimer's disease, these results suggest that 5-HT1A antagonists may have a role in the treatment of some of the cognitive symptoms of dementia.

  17. 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

  18. NMDA-induced glutamate and aspartate release from rat cortical pyramidal neurones: evidence for modulation by a 5-HT1A antagonist.

    PubMed Central

    Dijk, S. N.; Francis, P. T.; Stratmann, G. C.; Bowen, D. M.

    1995-01-01

    1. We have investigated an aspect of the regulation of cortical pyramidal neurone activity. Microdialysis was used to assess whether topical application of drugs (in 10 microliter) to fill a burr hole over the frontal cortex, where part of the corticostriatal pathway originates, would change concentrations of the excitatory amino acids glutamate and aspartate in the striatum of the anaesthetized rat. 2. Topical application of N-methyl-D-aspartate (NMDA, 2 and 20 mM) dose-dependently increased glutamate and aspartate concentrations in the striatum. Coapplication of tetrodotoxin (10 microM) blocked the NMDA-evoked rise in these amino acids. A calcium-free medium, perfused through the probe also blocked the rise, indicating that it was due to an exocytotic mechanism in the striatum. 3. It was hypothesized that the rise observed was due to an increase in the activity of the corticostriatal pathway. As 5-hydroxytryptamine1A (5-HT1A) receptors are enriched on cell bodies of corticostriatal neurones, a selective 5-HT1A-antagonist (WAY 100135) was coapplied with the lower dose of NMDA. Compared to NMDA alone, coapplication of 50 microM WAY 100135 significantly increased glutamate release. This effect was sensitive to tetrodotoxin and calcium-dependent. Application of 50 microM WAY 100135 alone significantly enhanced glutamate release above baseline; this was also tested at 100 microM (not significant). 4. Compared to NMDA alone, coapplication of WAY 100135 (20 microM) significantly enhanced aspartate release; the mean value was also increased (not significantly) with 50 microM. This rise was calcium-dependent, but not tetrodotoxin-sensitive. WAY 100135 (100 microM) reduced NMDA-induced aspartate release.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7582540

  19. Improved efficacy of fluoxetine in increasing hippocampal 5-hydroxytryptamine outflow in 5-HT(1B) receptor knock-out mice.

    PubMed

    Malagié, Isabelle; David, Denis J; Jolliet, Pascale; Hen, René; Bourin, Michel; Gardier, Alain M

    2002-05-17

    To test for the contribution of the 5-HT(1B) receptor subtype in mediating the effects of fluoxetine, a selective serotonin reuptake inhibitor (SSRI), we used intracerebral in vivo microdialysis in awake, freely moving 5-HT(1B) receptor knock-out mice. We show that a single systemic administration of fluoxetine (1, 5 or 10 mg/kg, i.p.) increased extracellular serotonin levels [5-HT](ext) in the ventral hippocampus and frontal cortex of wild-type and mutant mice. However, in the ventral hippocampus, fluoxetine, at the three doses studied, induced a larger increase in [5-HT](ext) in knock-out than in wild-type mice. In the frontal cortex, the effect of fluoxetine did not differ between the two genotypes. The region-dependent response to fluoxetine described here in mutants confirms data we recently reported for another SSRI, paroxetine. These data suggest that 5-HT(1B) autoreceptors limit the effects of selective serotonin reuptake inhibitors on dialysate 5-HT levels at serotonergic nerve terminals located mainly in the ventral hippocampus. Alternative mechanisms, e.g., changes in 5-HT transporter and/or 5-HT(1A) receptor density in 5-HT(1B) receptor knock-out mice could also explain these findings.

  20. Anti-conflict effect of 5-HT1A agonists in rats: a new model for evaluating anxiolytic-like activity.

    PubMed

    Hascoët, M; Bourin, M; Todd, K G; Coüetoux du Tertre, A

    1994-01-01

    A new conflict procedure was developed to study the potential anti-punishment effects of 5-HT( 1A) agonists as compared to diazepam. In this paradigm, the opportunity existed for rats to choose during punished periods between immediate, punished reinforcement and delayed, non-punished reinforcement. The results confirm that, for non-sedative doses (1 mg/kg), diazepam increases the number of punished responses. Furthermore, the present paradigm seems sensitive for the detection of 5-HT(1A) activity. Buspirone, gepirone, ipsapirone, zalospirone and 8-OH-DPAT increased responding for immediate but punished reinforcement. 1-(2-pyrimidinyl)piperazine, the common metabolite of the azapirones, does not participate in their anti-conflict effect. NAN 190, a 5-HT(1A) antagonist, was shown to block the 5-HT(1A) agonists. The findings of the present study suggest that benzodiazepines and 5-HT( 1A) agonists reduce the capacity to tolerate delays in reward. Abnormality in serotonin systems may be associated with poor impulse control.

  1. The effect of urapidil, an alpha-1 adrenoceptor antagonist and a 5-HT1A agonist, on the vascular tone of the porcine coronary and pulmonary arteries, the rat aorta and the human pulmonary artery.

    PubMed

    Bopp, Claire; Auger, Cyril; Diemunsch, Pierre; Schini-Kerth, Valérie

    2016-05-15

    Urapidil (Eupressyl(®)) an antihypertensive drug acting as an α1 antagonist and a 5-HT1A agonist, may be of special interest in the treatment of hypertension associated with preeclamptic toxaemia and hypoxia-induced pulmonary arterial vasoconstriction. However, the effect of urapidil on vascular tone has been poorly investigated. Vascular reactivity was evaluated using pulmonary and coronary arteries from 36 pigs, aortae from 22 rats and 9 human pulmonary artery samples suspended in organ chambers. Concentration-relaxation curves either to urapidil, 5-HT, or the 5-HT1A receptor agonist 8-OH-DPAT were constructed after pre-contraction of rings. Pig pulmonary and coronary artery rings were contracted with U46619, a thromboxane mimetic, rat aortic rings with either endothelin-1 or phenylephrine, and human pulmonary artery rings with U46619 or phenylephrine. Urapidil markedly inhibited phenylephrine-induced contractions in rat aortic rings with and without endothelium with a more pronounced effect observed in rings without endothelium. Both 5-HT and 8-OH-DPAT failed to induce relaxation in rat aortic rings with an intact endothelium. 5-HT, but not urapidil and 8-OH-DPAT, induced a concentration-dependent relaxation in the porcine coronary and pulmonary artery rings with an intact endothelium (P<0.05). 5-HT and phenylephrine but not urapidil caused concentration-dependent contractions in human pulmonary artery rings. The present findings, while confirming that urapidil is a potent inhibitor of α1-adrenoceptor-induced contraction, do not support the role of 5-HT1A receptor activation in the control of the vascular tone of the different types of arteries tested in response to urapidil. In addition, they indicate that urapidil seems to preferentially target arteries with endothelial dysfunction.

  2. Modulating the rate and rhythmicity of perceptual rivalry alternations with the mixed 5-HT2A and 5-HT1A agonist psilocybin.

    PubMed

    Carter, Olivia L; Pettigrew, John D; Hasler, Felix; Wallis, Guy M; Liu, Guang B; Hell, Daniel; Vollenweider, Franz X

    2005-06-01

    Binocular rivalry occurs when different images are presented simultaneously to corresponding points within the left and right eyes. Under these conditions, the observer's perception will alternate between the two perceptual alternatives. Motivated by the reported link between the rate of perceptual alternations, symptoms of psychosis and an incidental observation that the rhythmicity of perceptual alternations during binocular rivalry was greatly increased 10 h after the consumption of LSD, this study aimed to investigate the pharmacology underlying binocular rivalry and to explore the connection between the timing of perceptual switching and psychosis. Psilocybin (4-phosphoryloxy-N,N-dimethyltryptamine, PY) was chosen for the study because, like LSD, it is known to act as an agonist at serotonin (5-HT)1A and 5-HT2A receptors and to produce an altered state sometimes marked by psychosis-like symptoms. A total of 12 healthy human volunteers were tested under placebo, low-dose (115 microg/kg) and high-dose (250 microg/kg) PY conditions. In line with predictions, under both low- and high-dose conditions, the results show that at 90 min postadministration (the peak of drug action), rate and rhythmicity of perceptual alternations were significantly reduced from placebo levels. Following the 90 min testing period, the perceptual switch rate successively increased, with some individuals showing increases well beyond pretest levels at the final testing, 360 min postadministration. However, as some subjects had still not returned to pretest levels by this time, the mean phase duration at 360 min was not found to differ significantly from placebo. Reflecting the drug-induced changes in rivalry phase durations, subjects showed clear changes in psychological state as indexed by the 5D-ASC (altered states of consciousness) rating scales. This study suggests the involvement of serotonergic pathways in binocular rivalry and supports the previously proposed role of a brainstem

  3. Systemic treatment with a 5HT1a agonist induces anti-oxidant protection and preserves the retina from mitochondrial oxidative stress.

    PubMed

    Biswal, Manas R; Ahmed, Chulbul M; Ildefonso, Cristhian J; Han, Pingyang; Li, Hong; Jivanji, Hiral; Mao, Haoyu; Lewin, Alfred S

    2015-11-01

    Chronic oxidative stress contributes to age related diseases including age related macular degeneration (AMD). Earlier work showed that the 5-hydroxy-tryptamine 1a (5HT1a) receptor agonist 8-hydroxy-2-(di-n-propylamino)-tetralin (8-OH-DPAT) protects retinal pigment epithelium (RPE) cells from hydrogen peroxide treatment and mouse retinas from oxidative insults including light injury. In our current experiments, RPE derived cells subjected to mitochondrial oxidative stress were protected from cell death by the up-regulation of anti-oxidant enzymes and of the metal ion chaperone metallothionein. Differentiated RPE cells were resistant to oxidative stress, and the expression of genes for protective proteins was highly increased by oxidative stress plus drug treatment. In mice treated with 8-OH-DPAT, the same genes (MT1, HO1, NqO1, Cat, Sod1) were induced in the neural retina, but the drug did not affect the expression of Sod2, the gene for manganese superoxide dismutase. We used a mouse strain deleted for Sod2 in the RPE to accelerate age-related oxidative stress in the retina and to test the impact of 8-OH-DPAT on the photoreceptor and RPE degeneration developed in these mice. Treatment of mice with daily injections of the drug led to increased electroretinogram (ERG) amplitudes in dark-adapted mice and to a slight improvement in visual acuity. Most strikingly, in mice treated with a high dose of the drug (5 mg/kg) the structure of the RPE and Bruch's membrane and the normal architecture of photoreceptor outer segments were preserved. These results suggest that systemic treatment with this class of drugs may be useful in preventing geographic atrophy, the advanced form of dry AMD, which is characterized by RPE degeneration.

  4. Effects of chronic paroxetine treatment on dialysate serotonin in 5-HT1B receptor knockout mice.

    PubMed

    Gardier, A M; David, D J; Jego, G; Przybylski, C; Jacquot, C; Durier, S; Gruwez, B; Douvier, E; Beauverie, P; Poisson, N; Hen, R; Bourin, M

    2003-07-01

    The role of serotonin (5-HT)1B receptors in the mechanism of action of selective serotonin re-uptake inhibitors (SSRI) was studied by using intracerebral in vivo microdialysis in conscious, freely moving wild-type and 5-HT1B receptor knockout (KO 5-HT1B) mice in order to compare the effects of chronic administration of paroxetine via osmotic minipumps (1 mg per kg per day for 14 days) on extracellular 5-HT levels ([5-HT]ext) in the medial prefrontal cortex and ventral hippocampus. Basal [5-HT]ext values in the medial prefrontal cortex and ventral hippocampus, approximately 20 h after removing the minipump, were not altered by chronic paroxetine treatment in both genotypes. On day 15, in the ventral hippocampus, an acute paroxetine challenge (1 mg/kg i.p.) induced a larger increase in [5-HT]ext in saline-pretreated mutant than in wild-type mice. This difference between the two genotypes in the effect of the paroxetine challenge persisted following chronic paroxetine treatment. Conversely, in the medial prefrontal cortex, the paroxetine challenge increased [5-HT]ext similarly in saline-pretreated mice of both genotypes. Such a challenge produced a further increase in cortical [5-HT]ext compared with that in saline-pretreated groups of both genotypes, but no differences were found between genotypes following chronic treatment. To avoid the interaction with raphe 5-HT1A autoreceptors, 1 micro m paroxetine was perfused locally through the dialysis probe implanted in the ventral hippocampus; similar increases in hippocampal [5-HT]ext were found in acutely or chronically treated wild-type mice. Systemic administration of the mixed 5-HT1B/1D receptor antagonist GR 127935 (4 mg/kg) in chronically treated wild-type mice potentiated the effect of a paroxetine challenge dose on [5-HT]ext in the ventral hippocampus, whereas systemic administration of the selective 5-HT1A receptor antagonist WAY 100635 did not. By using the zero net flux method of quantitative microdialysis in

  5. Characterization of MDL 73005EF as a 5-HT1A selective ligand and its effects in animal models of anxiety: comparison with buspirone, 8-OH-DPAT and diazepam.

    PubMed Central

    Moser, P. C.; Tricklebank, M. D.; Middlemiss, D. N.; Mir, A. K.; Hibert, M. F.; Fozard, J. R.

    1990-01-01

    1. With radioligand binding techniques, MDL 73005 EF (8-[2-(2,3-dihydro-1,4-benzodioxin-2-yl-methylamino)ethyl]-8-az aspiro[4, 5]decane-7,9-dione methyl sulphonate) shows high affinity (pIC50 8.6) and selectivity (greater than 100 fold compared to other monoamine and benzodiazepine receptor sites) for the 5-hydroxytryptamine (5-HT)1A recognition site; it was both more potent and more selective than buspirone in this respect. 2. In rats pretreated with reserpine, 8-hydroxy-2-(di-n-propyl-amino) tetralin (8-OH-DPAT) induced forepaw treading and flat body posture; in the same model, MDL 73005EF and buspirone showed minimal agonist activity and at high doses MDL 73005EF inhibited responses to 8-OH-DPAT. 3. In rats trained to discriminate 8-OH-DPAT from saline in a drug discrimination paradigm, both MDL 73005EF and buspirone generalized dose-dependently and completely to the 8-OH-DPAT cue. 4. To define the anxiolytic potential of MDL 73005EF, it was examined in the elevated plus-maze test and in the water-lick conflict test in comparison with diazepam and buspirone. In both tests MDL 73005EF induced effects similar to those seen following diazepam. Buspirone had similar effects to both MDL 73005EF and diazepam in the water-lick conflict test but opposite effects in the elevated plus-maze. 8-OH-DPAT also had opposite effects in the elevated plus-maze test to MDL 73005EF and diazepam. 5. The anti-conflict effects of MDL 73005EF were reversed by low doses of the 5-HT1A receptor agonist, 8-OH-DPAT; those of buspirone were neither antagonised nor mimicked by 8-OH-DPAT.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1970269

  6. Serotonergic involvement in the amelioration of behavioral abnormalities in dopamine transporter knockout mice by nicotine.

    PubMed

    Uchiumi, Osamu; Kasahara, Yoshiyuki; Fukui, Asami; Hall, F Scott; Uhl, George R; Sora, Ichiro

    2013-01-01

    Dopamine transporter knockout (DAT KO) mice exhibit elevated extracellular dopamine levels in brain regions that include the striatum and the nucleus accumbens, but not the prefrontal cortex. DAT KO mice model some aspects of psychiatric disorders, including schizophrenia. Smoking is more common in patients with schizophrenia, suggesting that nicotine might ameliorate aspects of the behavioral abnormalities and/or treatment side effects seen in these individuals. We report nicotine-induced normalization of effects on locomotion and prepulse inhibition of acoustic startle (PPI) in DAT KO mice that require intact serotonin 5-HT1A systems. First, we observed that the marked hyperactivity displayed by DAT KO mice was reduced by administration of nicotine. This nicotine effect was blocked by pretreatment with the non-specific nicotinic acetylcholine (nACh) receptor antagonist mecamylamine, or the 5-HT1A antagonist WAY100635. Secondly, we examined the effects of nicotine on PPI in DAT KO mice. Treatment with nicotine significantly ameliorated the PPI deficits observed in DAT KO mice. The ameliorating action of nicotine on PPI deficits in DAT KO mice was blocked by mecamylamine, the α₇ nACh receptor antagonist methyllycaconitine or WAY100635, while the α₄β₂ nACh receptor antagonist dihydro-β-erythroidinehydrobromide (DHβE) produced only a non-significant trend toward attenuation of nicotine effects. Finally, we observed that administration of the 5-HT1A receptor agonist 8-OH-DPAT also ameliorated the deficit in PPI observed in DAT KO mice. This amelioration was antagonized by pretreatment with WAY100635. These data support the idea that nicotine might ameliorate some of the cognitive dysfunctions found in schizophrenia in a 5-HT1A-dependent fashion. This article is part of a Special Issue entitled 'Cognitive Enhancers'.

  7. 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.

  8. Effect of the 5-HT(1A) partial agonist buspirone on regional brain electrical activity in man: a functional neuroimaging study using low-resolution electromagnetic tomography (LORETA).

    PubMed

    Anderer, P; Saletu, B; Pascual-Marqui, R D

    2000-12-01

    In a double-blind, placebo-controlled study, the effects of 20 mg buspirone - a 5-HT(1A) partial agonist - on regional electrical generators within the human brain were investigated utilizing three-dimensional EEG tomography. Nineteen-channel vigilance-controlled EEG recordings were carried out in 20 healthy subjects before and 1, 2, 4, 6 and 8 h after drug intake. Low-resolution electromagnetic tomography (LORETA; Key Institute for Brain-Mind Research, software: http://www.keyinst.unizh.ch) was computed from spectrally analyzed EEG data, and differences between drug- and placebo-induced changes were displayed as statistical parametric maps. Data were registered to the Talairach-Tournoux human brain atlas available as a digitized MRI (McConnell Brain Imaging Centre: http://www.bic.mni.mcgill.ca). At the pharmacodynamic peak (1st hour), buspirone increased theta and decreased fast alpha and beta sources. Areas of theta increase were mainly the left temporo-occipito-parietal and left prefrontal cortices, which is consistent with PET studies on buspirone-induced decreases in regional cerebral blood flow and fenfluramine-induced serotonin activation demonstrated by changes in regional cerebral glucose metabolism. In later hours (8th hour) with lower buspirone plasma levels, delta, theta, slow alpha and fast beta decreased, predominantly in the prefrontal and anterior limbic lobe. Whereas the results of the 1st hour speak for a slight CNS sedation (more in the sense of relaxation), those obtained in the 8th hour indicate activation. Thus, LORETA may provide useful and direct information on drug-induced changes in central nervous system function in man.

  9. Hepatic changes in metabolic gene expression in old ghrelin and ghrelin receptor knockout mice

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ghrelin knockout (GKO) and ghrelin receptor (growth hormone secretagogue receptor) knockout (GHSRKO) mice exhibit enhanced insulin sensitivity, but the mechanism is unclear. Insulin sensitivity declines with age and is inversely associated with accumulation of lipid in liver, a key glucoregulatory ...

  10. SB-649915-B, a novel 5-HT1A/B autoreceptor antagonist and serotonin reuptake inhibitor, is anxiolytic and displays fast onset activity in the rat high light social interaction test.

    PubMed

    Starr, Kathryn R; Price, Gary W; Watson, Jeannette M; Atkinson, Peter J; Arban, Roberto; Melotto, Sergio; Dawson, Lee A; Hagan, Jim J; Upton, Neil; Duxon, Mark S

    2007-10-01

    Preclinically, the combination of an SSRI and 5-HT autoreceptor antagonist has been shown to reduce the time to onset of anxiolytic activity compared to an SSRI alone. In accordance with this, clinical data suggest the coadministration of an SSRI and (+/-) pindolol can decrease the time to onset of anxiolytic/antidepressant activity. Thus, the dual-acting novel SSRI and 5-HT(1A/B) receptor antagonist, SB-649915-B, has been assessed in acute and chronic preclinical models of anxiolysis. SB-649915-B (0.1-1.0 mg/kg, i.p.) significantly reduced ultrasonic vocalization in male rat pups separated from their mothers (ED(50) of 0.17 mg/kg). In the marmoset human threat test SB-649915-B (3.0 and 10 mg/kg, s.c.) significantly reduced the number of postures with no effect on locomotion. In the rat high light social interaction (SI), SB-649915-B (1.0-7.5 mg/kg, t.i.d.) and paroxetine (3.0 mg/kg, once daily) were orally administered for 4, 7, and 21 days. Ex vivo inhibition of [(3)H]5-HT uptake was also measured following SI. SB-649915-B and paroxetine had no effect on SI after 4 days. In contrast to paroxetine, SB-649915-B (1.0 and 3.0 mg/kg, p.o., t.i.d.) significantly (p<0.05) increased SI time with no effect on locomotion, indicative of an anxiolytic-like profile on day 7. Anxiolysis was maintained after chronic (21 days) administration by which time paroxetine also increased SI significantly. 5-HT uptake was inhibited by SB-649915-B at all time points to a similar magnitude as that seen with paroxetine. In conclusion, SB-649915-B is acutely anxiolytic and reduces the latency to onset of anxiolytic behavior compared to paroxetine in the SI model.

  11. The Relevance of the Functional 5-HT1A Receptor Polymorphism for Attention and Working Memory Processes during Mental Rotation of Characters

    ERIC Educational Resources Information Center

    Beste, Christian; Heil, Martin; Domschke, Katharina; Konrad, Carsten

    2010-01-01

    Numerous lines of research indicate that attentional processes, working memory and saccadic processes are highly interrelated. In the current study, we examine the relation between these processes with respect to their cognitive-neurophysiological and neurobiological background by means of event-related potentials (ERPs) in a sample of N = 72…

  12. THE EFFECT OF SEROTONIN 5-HT1A, 5-HT2 RECEPTOR LIGANDS, KETOPROFEN AND THEIR COMBINATION IN MODELS OF INDUCED PAIN IN MICE.

    PubMed

    Zygmunt, Małgorzata; Chłoń-Rzepa, Grażyna; Sapa, Jacek

    2015-01-01

    The present study was carried out to investigate the effects of the 7-(3-chlorophenyl)piperazinylalkyl derivatives of 8-alkoxypurine-2,6-dione (compounds 1-4) in two animal models of induced pain and to compare their effects with ketoprofen and with their combination. All experiments were performed on albino mice. Mice were evaluated for their responsiveness to noxious stimuli using: the hot-plate test and the phenylbenzo-quinone-induced writhing test. All compounds showed analgesic activity only in the writhing test. The analgesic activities of compounds 3 and 4 were similar to ketoprofen. The compounds slightly increased the analgesic effect of ketoprofen when used in combination in the visceral type of pain. The possible mechanisms of the antinociceptive effect of these compounds are thought to involve the activation of analgesic effect mediated by the serotonergic pathways or combination of this mechanism with other important mediators playing a role in pain modulation.

  13. Retinal Neuroprotective Effects of Flibanserin, an FDA-Approved Dual Serotonin Receptor Agonist-Antagonist

    PubMed Central

    Ryals, Renee C.; Ku, Cristy A.; Fischer, Cody M.; Patel, Rachel C.; Datta, Shreya; Yang, Paul; Wen, Yuquan; Hen, René; Pennesi, Mark E.

    2016-01-01

    Purpose To assess the neuroprotective effects of flibanserin (formerly BIMT-17), a dual 5-HT1A agonist and 5-HT2A antagonist, in a light-induced retinopathy model. Methods Albino BALB/c mice were injected intraperitoneally with either vehicle or increasing doses of flibanserin ranging from 0.75 to 15 mg/kg flibanserin. To assess 5-HT1A-mediated effects, BALB/c mice were injected with 10 mg/kg WAY 100635, a 5-HT1A antagonist, prior to 6 mg/kg flibanserin and 5-HT1A knockout mice were injected with 6 mg/kg flibanserin. Injections were administered once immediately prior to light exposure or over the course of five days. Light exposure lasted for one hour at an intensity of 10,000 lux. Retinal structure was assessed using spectral domain optical coherence tomography and retinal function was assessed using electroretinography. To investigate the mechanisms of flibanserin-mediated neuroprotection, gene expression, measured by RT-qPCR, was assessed following five days of daily 15 mg/kg flibanserin injections. Results A five-day treatment regimen of 3 to 15 mg/kg of flibanserin significantly preserved outer retinal structure and function in a dose-dependent manner. Additionally, a single-day treatment regimen of 6 to 15 mg/kg of flibanserin still provided significant protection. The action of flibanserin was hindered by the 5-HT1A antagonist, WAY 100635, and was not effective in 5-HT1A knockout mice. Creb, c-Jun, c-Fos, Bcl-2, Cast1, Nqo1, Sod1, and Cat were significantly increased in flibanserin-injected mice versus vehicle-injected mice. Conclusions Intraperitoneal delivery of flibanserin in a light-induced retinopathy mouse model provides retinal neuroprotection. Mechanistic data suggests that this effect is mediated through 5-HT1A receptors and that flibanserin augments the expression of genes capable of reducing mitochondrial dysfunction and oxidative stress. Since flibanserin is already FDA-approved for other indications, the potential to repurpose this drug for

  14. Distribution of serotonin 5-HT1A-binding sites in the brainstem and the hypothalamus, and their roles in 5-HT-induced sleep and ingestive behaviors in rock pigeons (Columba livia).

    PubMed

    dos Santos, Tiago Souza; Krüger, Jéssica; Melleu, Fernando Falkenburger; Herold, Christina; Zilles, Karl; Poli, Anicleto; Güntürkün, Onur; Marino-Neto, José

    2015-12-15

    Serotonin 1A receptors (5-HT1ARs), which are widely distributed in the mammalian brain, participate in cognitive and emotional functions. In birds, 5-HT1ARs are expressed in prosencephalic areas involved in visual and cognitive functions. Diverse evidence supports 5-HT1AR-mediated 5-HT-induced ingestive and sleep behaviors in birds. Here, we describe the distribution of 5-HT1ARs in the hypothalamus and brainstem of birds, analyze their potential roles in sleep and ingestive behaviors, and attempt to determine the involvement of auto-/hetero-5-HT1ARs in these behaviors. In 6 pigeons, the anatomical distribution of [(3)H]8-OH-DPAT binding in the rostral brainstem and hypothalamus was examined. Ingestive/sleep behaviors were recorded (1h) in 16 pigeons pretreated with MM77 (a heterosynaptic 5-HT1AR antagonist; 23 or 69 nmol) for 20 min, followed by intracerebroventricular ICV injection of 5-HT (N:8; 150 nmol), 8-OH-DPAT (DPAT, a 5-HT1A,7R agonist, 30 nmol N:8) or vehicle. 5-HT- and DPAT-induced sleep and ingestive behaviors, brainstem 5-HT neuronal density and brain 5-HT content were examined in 12 pigeons, pretreated by ICV with the 5-HT neurotoxin 5,7-dihydroxytryptamine (5,7-DHT) or vehicle (N:6/group). The distribution of brainstem and diencephalic c-Fos immunoreactivity after ICV injection of 5-HT, DPAT or vehicle (N:5/group) into birds provided with or denied access to water is also described. 5-HT1ARs are concentrated in the brainstem 5-HTergic areas and throughout the periventricular hypothalamus, preoptic nuclei and circumventricular organs. 5-HT and DPAT produced a complex c-Fos expression pattern in the 5-HT1AR-enriched preoptic hypothalamus and the circumventricular organs, which are related to drinking and sleep regulation, but modestly affected c-Fos expression in 5-HTergic neurons. The 5-HT-induced ingestivebehaviors and the 5-HT- and DPAT-induced sleep behaviors were reduced by MM77 pretreatment. 5,7-DHT increased sleep per se, decreased tryptophan

  15. Oestrogen receptor knockout mice: roles for oestrogen receptors alpha and beta in reproductive tissues.

    PubMed

    Hewitt, Sylvia Curtis; Korach, Kenneth S

    2003-02-01

    Oestrogen is an essential component of female reproduction, with well-characterized functions in the uterus, ovaries, mammary gland and hypothalamic-pituitary axis. The mechanism of oestrogen action involves mediation of the rate of transcription by nuclear-localized oestrogen receptor molecules. Two oestrogen receptors are present in mouse tissues, oestrogen receptors alpha and beta. Each receptor exhibits differential tissue expression patterns. Mouse models with genetically engineered disruption or 'knockout' of the oestrogen receptors have been developed. Characterization of the resulting defects in reproductive tissues as well as alterations in physiological and genomic responses has given insight into the receptor-mediated effects of oestrogen in reproduction. Oestrogen receptor alpha knockout females are infertile because they are anovulatory, have disruption in LH regulation and have uteri that are insensitive to oestrogen. In contrast, oestrogen receptor beta knockout females are sub-fertile and primarily lack efficient ovulatory function. Mice with deletion of both oestrogen receptors alpha and beta are similar to those lacking oestrogen receptor alpha only, but exhibit a unique ovarian pathology. These observed phenotypes elucidate the relative roles of the oestrogen receptors in reproductive functions of female rodents.

  16. The peripheral cannabinoid receptor knockout mice: an update

    PubMed Central

    Buckley, N E

    2007-01-01

    This review gives an overview of the CB2 receptor (CB2R) knockout (CB2R−/−) mice phenotype and the work that has been carried out using this mutant mouse. Using the CB2R−/− mice, investigators have discovered the involvement of CB2R on immune cell function and development, infection, embryonic development, bone loss, liver disorders, pain, autoimmune inflammation, allergic dermatitis, atherosclerosis, apoptosis and chemotaxis. Using the CB2R−/− mice, investigators have also found that this receptor is not involved in cannabinoid-induced hypotension. In addition, the CB2R−/− mice have been used to determine specific tissue CB2R expression. The specificity of synthetic cannabinoid agonists, antagonists and anti-CB2R antibodies has been screened using tissues from CB2R−/− mice. Thus, the use of this mouse model has greatly helped reveal the diverse events involving the CB2R, and has aided in drug and antibody screening. PMID:17965741

  17. Bone Growth and Turnover in Progesterone Receptor Knockout Mice

    PubMed Central

    Rickard, David J.; Iwaniec, Urszula T.; Evans, Glenda; Hefferan, Theresa E.; Hunter, Jamie C.; Waters, Katrina M.; Lydon, John P.; O’Malley, Bert W.; Khosla, Sundeep; Spelsberg, Thomas C.; Turner, Russell T.

    2008-01-01

    The role of progesterone receptor (PR) signaling in skeletal metabolism is controversial. To address whether signaling through the PR is necessary for normal bone growth and turnover, we performed histomorphometric and microcomputed tomography analyses of bone from homozygous female PR knockout (PRKO) mice at 6, 12, and 26 wk of age. These mice possess a null mutation of the PR locus, which blocks the gene expression of A and B isoforms of PR. Body weight gain, uterine weight gain, and tibia longitudinal bone growth were normal in PRKO mice. In contrast, total, cancellous, and cortical bone mass were increased in the humerus of 12-wk-old PRKO mice, whereas cortical and cancellous bone mass in the tibia was normal. At 26 wk of age, cancellous bone area in the proximal tibia metaphysis of PRKO mice was 153% greater than age matched wild-type mice. The improved cancellous bone balance in 6-month-old PRKO mice was associated with elevated bone formation and a tendency toward reduced osteoclast perimeter. Taken together, these findings suggest that PR signaling in mice is not essential for bone growth and turnover. However, at some skeletal sites, PR signaling attenuates the accumulation of cortical and cancellous bone mass during adolescence. PMID:18276762

  18. Bone growth and turnover in progesterone receptor knockout mice.

    SciTech Connect

    Rickard, David J.; Iwaniec, Urszula T.; Evans, Glenda; Hefferan, Theresa E.; Hunter, Jaime C.; Waters, Katrina M.; Lydon, John P.; O'Malley, Bert W.; Khosla, Sundeep; Spelsberg, Thomas C.; Turner, Russell T.

    2008-05-01

    The role of progesterone receptor (PR) signaling in skeletal metabolism is controversial. To address whether signaling through the PR is necessary for normal bone growth and turnover, we performed histomorphometric and mCT analyses of bone from homozygous female PR knockout (PRKO) mice at 6, 12, and 26 weeks of age. These mice possess a null mutation of the PR locus, which blocks the gene expression of A and B isoforms of PR. Body weight gain, uterine weight gain and tibia longitudinal bone growth was normal in PRKO mice. In contrast, total and cortical bone mass were increased in long bones of post-pubertal (12 and 26-week-old) PRKO mice, whereas cancellous bone mass was normal in the tibia but increased in the humerus. The striking 57% decrease in cancellous bone from the proximal tibia metaphysis which occurred between 6 and 26 weeks in WT mice was abolished in PRKO mice. The improved bone balance in aging PRKO mice was associated with elevated bone formation and a tendency toward reduced osteoclast perimeter. Taken together, these findings suggest that PR signaling in mice attenuates the accumulation of cortical bone mass during adolescence and is required for early age-related loss of cancellous bone.

  19. INDUCTION OF MAMMARY GLAND DEVELOPMENT IN ESTROGEN RECEPTOR-ALPHA KNOCKOUT MICE

    EPA Science Inventory

    Mammary glands from the estrogen receptor knockout ( ERKO) mouse do not undergo ductal morphogenesis or alveolar development. Disrupted Er signaling may result in reduced estrogen-responsive gene products in the mammary gland or reduced mammotropic hormones that contribute t...

  20. Effects of D1 receptor knockout on fear and reward learning.

    PubMed

    Abraham, Antony D; Neve, Kim A; Lattal, K Matthew

    2016-09-01

    Dopamine signaling is involved in a variety of neurobiological processes that contribute to learning and memory. D1-like dopamine receptors (including D1 and D5 receptors) are thought to be involved in memory and reward processes, but pharmacological approaches have been limited in their ability to distinguish between D1 and D5 receptors. Here, we examine the effects of a specific knockout of D1 receptors in associative learning tasks involving aversive (shock) or appetitive (cocaine) unconditioned stimuli. We find that D1 knockout mice show similar levels of cued and contextual fear conditioning to WT controls following conditioning protocols involving one, two, or four shocks. D1 knockout mice show increased generalization of fear conditioning and extinction across contexts, revealed as increased freezing to a novel context following conditioning and decreased freezing to an extinguished cue during a contextual renewal test. Further, D1 knockout mice show mild enhancements in extinction following an injection of SKF81297, a D1/D5 receptor agonist, suggesting a role for D5 receptors in extinction enhancements induced by nonspecific pharmacological agonists. Finally, although D1 knockout mice show decreased locomotion induced by cocaine, they are able to form a cocaine-induced conditioned place preference. We discuss these findings in terms of the role of dopamine D1 receptors in general learning and memory processes. PMID:27423521

  1. Rescue of the mineralocorticoid receptor knock-out mouse.

    PubMed

    Bleich, M; Warth, R; Schmidt-Hieber, M; Schulz-Baldes, A; Hasselblatt, P; Fisch, D; Berger, S; Kunzelmann, K; Kriz, W; Schütz, G; Greger, R

    1999-08-01

    The mineralocorticoid receptor knock-out mouse (MR-/-), resembling inborn pseudohypoaldosteronism, dies 8-12 days after birth in circulatory failure with all the signs of terminal volume contraction. The present study aimed to examine the functional defects in the kidney and colon in detail and to attempt to rescue these mice. In neonatal (nn) MR-/- the amiloride-sensitive short-circuit current in the colon was reduced to approximately one-third compared to controls (MR+/+ and MR+/-). In isolated in vitro perfused collecting ducts the amiloride-induced hyperpolarization of the basolateral membrane (Vbl) of nn MR-/- was similar to that of controls, but urinary Na+ excretion was markedly increased to 4.3 micromol/day.g (BW). Based on this measured urinary Na+ loss we tried to rescue nn MR-/- mice by injecting NaCl twice daily (3.85 micromol/g BW), corresponding to 22 microliter of isotonic saline/g BW subcutaneously. This regimen was continued until the animals had reached a body mass of 8.5 g. Thereafter, in addition to normal chow and tap water, NaCl drinking water (333 mmol/l) and pellets soaked in 333 mmol/l NaCl were offered. Unlike the untreated nn MR-/- most of these mice survived. The adult animals were examined between days 27 and 41, some were used for breeding. When compared to age-matched controls the growth of MR-/- was delayed until day 20. Then their growth curve increased in slope and reached that of controls. MR-/- retained their Na+-losing defect. Amiloride's effect on urinary Na+ excretion was not significant in MR-/- mice and the effect on Vbl in isolated cortical collecting ducts was attenuated. The renin-producing cells were hypertrophic and hyperplastic. Plasma renin and aldosterone concentrations were significantly elevated in MR-/- mice. These data indicate that MR-/- can be rescued by timely and matched NaCl substitutions. This enables the animals to develop through a critical phase of life, after which they adapt their oral salt and water

  2. Modulation of GABA release from the thalamic reticular nucleus by cocaine and caffeine: role of serotonin receptors.

    PubMed

    Goitia, Belén; Rivero-Echeto, María Celeste; Weisstaub, Noelia V; Gingrich, Jay A; Garcia-Rill, Edgar; Bisagno, Verónica; Urbano, Francisco J

    2016-02-01

    Serotonin receptors are targets of drug therapies for a variety of neuropsychiatric and neurodegenerative disorders. Cocaine inhibits the re-uptake of serotonin (5-HT), dopamine, and noradrenaline, whereas caffeine blocks adenosine receptors and opens ryanodine receptors in the endoplasmic reticulum. We studied how 5-HT and adenosine affected spontaneous GABAergic transmission from thalamic reticular nucleus. We combined whole-cell patch clamp recordings of miniature inhibitory post-synaptic currents (mIPSCs) in ventrobasal thalamic neurons during local (puff) application of 5-HT in wild type (WT) or knockout mice lacking 5-HT2A receptors (5-HT2A -/-). Inhibition of mIPSCs frequency by low (10 μM) and high (100 μM) 5-HT concentrations was observed in ventrobasal neurons from 5-HT2A -/- mice. In WT mice, only 100 μM 5-HT significantly reduced mIPSCs frequency. In 5-HT2A -/- mice, NAN-190, a specific 5-HT1A antagonist, prevented the 100 μM 5-HT inhibition while blocking H-currents that prolonged inhibition during post-puff periods. The inhibitory effects of 100 μM 5-HT were enhanced in cocaine binge-treated 5-HT2A -/- mice. Caffeine binge treatment did not affect 5-HT-mediated inhibition. Our findings suggest that both 5-HT1A and 5-HT2A receptors are present in pre-synaptic thalamic reticular nucleus terminals. Serotonergic-mediated inhibition of GABA release could underlie aberrant thalamocortical physiology described after repetitive consumption of cocaine. Our findings suggest that both 5-HT1A , 5-HT2A and A1 receptors are present in pre-synaptic TRN terminals. 5-HT1A and A1 receptors would down-regulate adenylate cyclase, whereas 5-HT1A would also increase the probability of the opening of G-protein-activated inwardly rectifying K(+) channels (GIRK). Sustained opening of GIRK channels would hyperpolarize pre-synaptic terminals activating H-currents, resulting in less GABA release. 5-HT2A -would activate PLC and IP3 , increasing intracellular [Ca(2+) ] and

  3. Enhanced sexual behaviors and androgen receptor immunoreactivity in the male progesterone receptor knockout mouse.

    PubMed

    Schneider, Johanna S; Burgess, Carly; Sleiter, Nicole C; DonCarlos, Lydia L; Lydon, John P; O'Malley, Bert; Levine, Jon E

    2005-10-01

    Reproductive and behavioral functions of progesterone receptors (PRs) in males were assessed by examining consequences of PR gene deletion. Basal hormone levels were measured in male progesterone receptor knockout (PRKO) mice and compared to wild-type (WT) counterparts. RIA of serum LH, testosterone, and progesterone levels revealed no significant differences. Levels of FSH were moderately but significantly lower and inhibin levels were higher in PRKOs; these differences were not accompanied by gross differences in testicular weight or morphology. PRKOs exhibited significant alterations in sexual behavior. In initial tests PRKOs exhibited reduced latency to mount, compared with WT. In second sessions, PRKOs again showed a significantly reduced latency to mount and increased likelihood of achieving ejaculation. RU486 treatment in WT produced increased mount and intromission frequency and decreased latency to intromission. In anxiety-related behavior tests, PRKO mice exhibited intermediate anxiety levels, compared with WT, suggesting that enhanced sexual behavior in PRKOs is not secondary to reduced anxiety. Immunohistochemical analysis revealed significantly enhanced androgen receptor expression in the medial preoptic nucleus and bed nucleus of the stria terminalis of PRKO. We conclude that testicular development and function and homeostatic regulation of the hypothalamic-pituitary testicular axis are altered to a lesser extent by PR gene deletion. In contrast, PR appears to play a substantial role in inhibiting the anticipatory/motivational components of male sexual behavior in the mouse. The biological significance of this inhibitory mechanism and the extent to which it is mediated by reduced androgen receptor expression remain to be clarified.

  4. Normal maternal behavior, but increased pup mortality, in conditional oxytocin receptor knockout females.

    PubMed

    Macbeth, Abbe H; Stepp, Jennifer E; Lee, Heon-Jin; Young, W Scott; Caldwell, Heather K

    2010-10-01

    Oxytocin (Oxt) and the Oxt receptor (Oxtr) are implicated in the onset of maternal behavior in a variety of species. Recently, we developed two Oxtr knockout lines: a total body knockout (Oxtr-/-) and a conditional Oxtr knockout (OxtrFB/FB) in which the Oxtr is lacking only in regions of the forebrain, allowing knockout females to potentially nurse and care for their biological offspring. In the current study, we assessed maternal behavior of postpartum OxtrFB/FB females toward their own pups and maternal behavior of virgin Oxtr-/- females toward foster pups and compared knockouts of both lines to wildtype (Oxtr+/+) littermates. We found that both Oxtr-/- and OxtrFB/FB females appear to have largely normal maternal behaviors. However, with first litters, approximately 40% of the OxtrFB/FB knockout dams experienced high pup mortality, compared to fewer than 10% of the Oxtr+/+ dams. We then went on to test whether or not this phenotype occurred in subsequent litters or when the dams were exposed to an environmental disturbance. We found that regardless of the degree of external disturbance, OxtrFB/FB females lost more pups on their first and second litters compared to wildtype females. Possible reasons for higher pup mortality in OxtrFB/FB females are discussed.

  5. 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.

  6. Functional Selectivity and Antidepressant Activity of Serotonin 1A Receptor Ligands

    PubMed Central

    Chilmonczyk, Zdzisław; Bojarski, Andrzej Jacek; Pilc, Andrzej; Sylte, Ingebrigt

    2015-01-01

    Serotonin (5-HT) is a monoamine neurotransmitter that plays an important role in physiological functions. 5-HT has been implicated in sleep, feeding, sexual behavior, temperature regulation, pain, and cognition as well as in pathological states including disorders connected to mood, anxiety, psychosis and pain. 5-HT1A receptors have for a long time been considered as an interesting target for the action of antidepressant drugs. It was postulated that postsynaptic 5-HT1A agonists could form a new class of antidepressant drugs, and mixed 5-HT1A receptor ligands/serotonin transporter (SERT) inhibitors seem to possess an interesting pharmacological profile. It should, however, be noted that 5-HT1A receptors can activate several different biochemical pathways and signal through both G protein-dependent and G protein-independent pathways. The variables that affect the multiplicity of 5-HT1A receptor signaling pathways would thus result from the summation of effects specific to the host cell milieu. Moreover, receptor trafficking appears different at pre- and postsynaptic sites. It should also be noted that the 5-HT1A receptor cooperates with other signal transduction systems (like the 5-HT1B or 5-HT2A/2B/2C receptors, the GABAergic and the glutaminergic systems), which also contribute to its antidepressant and/or anxiolytic activity. Thus identifying brain specific molecular targets for 5-HT1A receptor ligands may result in a better targeting, raising a hope for more effective medicines for various pathologies. PMID:26262615

  7. Functional Selectivity and Antidepressant Activity of Serotonin 1A Receptor Ligands.

    PubMed

    Chilmonczyk, Zdzisław; Bojarski, Andrzej Jacek; Pilc, Andrzej; Sylte, Ingebrigt

    2015-01-01

    Serotonin (5-HT) is a monoamine neurotransmitter that plays an important role in physiological functions. 5-HT has been implicated in sleep, feeding, sexual behavior, temperature regulation, pain, and cognition as well as in pathological states including disorders connected to mood, anxiety, psychosis and pain. 5-HT1A receptors have for a long time been considered as an interesting target for the action of antidepressant drugs. It was postulated that postsynaptic 5-HT1A agonists could form a new class of antidepressant drugs, and mixed 5-HT1A receptor ligands/serotonin transporter (SERT) inhibitors seem to possess an interesting pharmacological profile. It should, however, be noted that 5-HT1A receptors can activate several different biochemical pathways and signal through both G protein-dependent and G protein-independent pathways. The variables that affect the multiplicity of 5-HT1A receptor signaling pathways would thus result from the summation of effects specific to the host cell milieu. Moreover, receptor trafficking appears different at pre- and postsynaptic sites. It should also be noted that the 5-HT1A receptor cooperates with other signal transduction systems (like the 5-HT1B or 5-HT2A/2B/2C receptors, the GABAergic and the glutaminergic systems), which also contribute to its antidepressant and/or anxiolytic activity. Thus identifying brain specific molecular targets for 5-HT1A receptor ligands may result in a better targeting, raising a hope for more effective medicines for various pathologies. PMID:26262615

  8. Lack of self-administration of cocaine in dopamine D1 receptor knock-out mice.

    PubMed

    Caine, S Barak; Thomsen, Morgane; Gabriel, Kara I; Berkowitz, Jill S; Gold, Lisa H; Koob, George F; Tonegawa, Susumu; Zhang, Jianhua; Xu, Ming

    2007-11-28

    Evidence suggests a critical role for dopamine in the reinforcing effects of cocaine in rats and primates. However, self-administration has been less often studied in the mouse species, and, to date, "knock-out" of individual dopamine-related genes in mice has not been reported to reduce the reinforcing effects of cocaine. We studied the dopamine D1 receptor and cocaine self-administration in mice using a combination of gene-targeted mutation and pharmacological tools. Two cohorts with varied breeding and experimental histories were tested, and, in both cohorts, there was a significant decrease in the number of D1 receptor knock-out mice that met criteria for acquisition of cocaine self-administration (2 of 23) relative to wild-type mice (27 of 32). After extinction of responding with saline self-administration, dose-response studies showed that cocaine reliably and dose dependently maintained responding greater than saline in all wild-type mice but in none of the D1 receptor knock-out mice. The D1-like agonist SKF 82958 (2,3,4,5,-tetrahydro-6-chloro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine hydrobromide) and the D2-like agonist quinelorane both functioned as positive reinforcers in wild-type mice but not in D1 receptor mutant mice, whereas food and intravenous injections of the opioid agonist remifentanil functioned as positive reinforcers in both genotypes. Finally, pretreatment with the D1-like antagonist SCH 23390 [R-(+)-8-chloro-2,3,4,5-tetrahydro-3-methyl-5-phenyl-1H-3-benzazepine-7-01] produced surmountable antagonism of the reinforcing effects of cocaine in the commonly used strain C57BL/6J. We conclude that D1 receptor knock-out mice do not reliably self-administer cocaine and that the D1 receptor is critical for the reinforcing effects of cocaine and other dopamine agonists, but not food or opioids, in mice.

  9. Gender-specific alteration of adrenergic responses in small femoral arteries from estrogen receptor-beta knockout mice.

    PubMed

    Luksha, Leonid; Poston, Lucilla; Gustafsson, Jan-Ake; Aghajanova, Lusine; Kublickiene, Karolina

    2005-11-01

    Estrogen receptor-beta knockout mice become hypertensive as they age, and males have a higher blood pressure than females. We hypothesized that the absence of estrogen receptor-beta may contribute to development of cardiovascular dysfunction by modification of adrenergic responsiveness in the peripheral vasculature. Small femoral arteries (internal diameter <200 microm) were isolated from estrogen receptor-beta knockout and wild-type mice and mounted on a wire myograph. Concentration-response curves to phenylephrine and norepinephrine were compared and the contribution of adrenoceptor subtypes established using specific agonists and antagonists. The involvement of endothelial factors in the modulation of resting tone was also investigated and immunohistochemical analysis used to confirm the presence or absence of estrogen receptor expression. Compared with wild type, arteries from estrogen receptor-beta knockout male, but not female, mice demonstrated gender-specific enhancement of the response to phenylephrine (alpha1-adrenoceptor agonist), which was accompanied by elevated basal tension attributable to endothelial factors. Contractile responses to the mixed adrenoceptor agonist norepinephrine did not differ significantly between estrogen receptor-beta knockout and wild type; however, beta-adrenoceptor inhibition unmasked an enhanced underlying alpha1-adrenoceptor responsiveness in estrogen receptor-beta knockout males. beta-adrenoceptor-mediated dilatation was also enhanced in estrogen receptor-beta knockout versus wild-type males. We suggest that estrogen receptor-beta modifies the adrenergic control of small artery tone in males but not in females.

  10. [Antidepressants, stressors and the serotonin 1A receptor].

    PubMed

    Kirilly, Eszter; Gonda, Xénia; Bagdy, György

    2015-06-01

    5-HT(1A) receptor is a receptor of surprises. Buspirone, an anxiolytic drug with a then yet unidentified mechanism of action had been marketed for years when it was discovered that it is a 5-HT(1A) partial agonist. Several more years had to pass before it was accepted that this receptor plays the key role in the action mechanism of buspirone. This was followed by further surprises. It was discovered that in spite of its anxiolytic effect buspirone activates the hypothalamic-pituitary-adrenal (HPA) stress axis, furthermore, it increases peripheral noradrenaline and adrenaline concentration via a central mechanism. Thus activation of this receptor leads to ACTH/corticosterone and catecholamine release and also increases beta-endorphine, oxytocin and prolactin secretion while decreasing body temperature, increasing food uptake, eliciting characteristic behavioural responses in rodents and also playing a role in the development of certain types of epilepsy. Human genetic studies revealed the role of 5-HT(1A) receptors in cognitive processes playing a role in the development of depression such as impulsiveness or response to environmental stress. This exceptionally wide spectrum of effects is attributable to the presence of 5-HT1A receptors in serotonergic as well as other, for example glutamatergic, cholinergic, dopaminergic and noradrenergic neurons. The majority of the effects of 5-HT(1A) receptors is manifested via the mediation of Gi proteins through the hyperpolarisation or inhibition of the neuron carrying the receptor. 5-HT(1A) receptors on serotonergic neurons can be found in the somatodendritic area and play a significant role in delaying the effects of antidepressants which is an obvious disadvantage. Therefore the newest serotonergic antidepressants including vilazodone and vortioxetine have been designed to possess 5-HT(1A) receptor partial agonist properties. In the present paper we focus primarily on the role of 5-HT(1A) receptors in stress and

  11. CB2 Cannabinoid Receptor Knockout in Mice Impairs Contextual Long-Term Memory and Enhances Spatial Working Memory.

    PubMed

    Li, Yong; Kim, Jimok

    2016-01-01

    Neurocognitive effects of cannabinoids have been extensively studied with a focus on CB1 cannabinoid receptors because CB1 receptors have been considered the major cannabinoid receptor in the nervous system. However, recent discoveries of CB2 cannabinoid receptors in the brain demand accurate determination of whether and how CB2 receptors are involved in the cognitive effects of cannabinoids. CB2 cannabinoid receptors are primarily involved in immune functions, but also implicated in psychiatric disorders such as schizophrenia and depression. Here, we examined the effects of CB2 receptor knockout in mice on memory to determine the roles of CB2 receptors in modulating cognitive function. Behavioral assays revealed that hippocampus-dependent, long-term contextual fear memory was impaired whereas hippocampus-independent, cued fear memory was normal in CB2 receptor knockout mice. These mice also displayed enhanced spatial working memory when tested in a Y-maze. Motor activity and anxiety of CB2 receptor knockout mice were intact when assessed in an open field arena and an elevated zero maze. In contrast to the knockout of CB2 receptors, acute blockade of CB2 receptors by AM603 in C57BL/6J mice had no effect on memory, motor activity, or anxiety. Our results suggest that CB2 cannabinoid receptors play diverse roles in regulating memory depending on memory types and/or brain areas.

  12. CB2 Cannabinoid Receptor Knockout in Mice Impairs Contextual Long-Term Memory and Enhances Spatial Working Memory

    PubMed Central

    Li, Yong; Kim, Jimok

    2016-01-01

    Neurocognitive effects of cannabinoids have been extensively studied with a focus on CB1 cannabinoid receptors because CB1 receptors have been considered the major cannabinoid receptor in the nervous system. However, recent discoveries of CB2 cannabinoid receptors in the brain demand accurate determination of whether and how CB2 receptors are involved in the cognitive effects of cannabinoids. CB2 cannabinoid receptors are primarily involved in immune functions, but also implicated in psychiatric disorders such as schizophrenia and depression. Here, we examined the effects of CB2 receptor knockout in mice on memory to determine the roles of CB2 receptors in modulating cognitive function. Behavioral assays revealed that hippocampus-dependent, long-term contextual fear memory was impaired whereas hippocampus-independent, cued fear memory was normal in CB2 receptor knockout mice. These mice also displayed enhanced spatial working memory when tested in a Y-maze. Motor activity and anxiety of CB2 receptor knockout mice were intact when assessed in an open field arena and an elevated zero maze. In contrast to the knockout of CB2 receptors, acute blockade of CB2 receptors by AM603 in C57BL/6J mice had no effect on memory, motor activity, or anxiety. Our results suggest that CB2 cannabinoid receptors play diverse roles in regulating memory depending on memory types and/or brain areas. PMID:26819779

  13. ABSENCE OF THE SP/SP RECEPTOR CIRCUITRY IN THE SP PRECURSOR KNOCKOUT MICE OR SP-RECEPTOR, NEUROKININ (NK1) KNOCKOUT MICE LEADS TO AN INHIBITED CYTOKINE RESPONSE IN GRANULOMAS ASSOCIATED WITH MURINE TAENIA CRASSICEPS INFECTION

    PubMed Central

    Garza, Armandina; Weinstock, Joel; Robinson, Prema

    2008-01-01

    Neurocysticercosis, caused by the cestode Taenia solium, is the most common parasitic infection of the human central nervous system that leads to seizures. Taenia crassiceps cysticercosis in mice is an experimental model for Taenia solium cysticercosis. Similar to the human infection, live parasites cause little or no granulomatous inflammation. Dying parasites initiate a granulomatous reaction. The neuropeptide, Substance P (SP), stimulates Th1 cytokine production. In the current studies, we determined if absence of SP/SP receptor circuitry in the SP precursor, preprotachykinin knockout or SP-receptor, neurokinin (NK1) knockout mice, affected granuloma cytokine production. We hence compared the levels of Th1 cytokines, IL-2 and IFN-γ, and levels of Th2/immunoregulatory cytokines, IL-4 and IL-10, by ELISA in T. crassiceps-induced granulomas derived from infected C57BL/6 wild type (WT) versus SP-Precursor knockout and NK1 knockout mice. We found that mean levels of IL-2, IFN-γ, IL-4, and IL-10 in infected, WT-derived granulomas were significantly higher than those of granulomas derived from infected SP-Precursor knockout or the NK1 receptor knockout mice. Levels of Th2/immunoregulatory cytokines, IL-4 and IL-10, were higher in early stage granulomas (histologically-staged on basis of evidence of parasite remnants) versus late stage granulomas (no parasite-remnants) of both knockouts, whereas the reverse was noted in WT-derived granulomas. These studies established that the absence of an SP/SP receptor circuitry in the SP precursor knockout mice or NK1 receptor knockout led to an inhibited cytokine response. PMID:18576810

  14. PROXIMAL GUT MUCOSAL EPITHELIAL HOMEOSTASIS IN AGED IL-1 TYPE I RECEPTOR KNOCKOUT MICE AFTER STARVATION

    PubMed Central

    Song, Juquan; Wolf, Steven E.; Wu, Xiao-Wu; Finnerty, Celeste C.; Herndon, David N.; Jeschke, Marc G.

    2010-01-01

    Background Previous studies have shown that starvation induces small bowel atrophy, and that atrophy diminishes with aging. In this experiment, we assessed whether starvation-induced atrophy of proximal gut mucosa is associated with the Interleukin-1 receptor (IL-1R) signaling pathway in aged mice. Materials and Methods Thirty 26-month-old IL-1R knockout mice and age-matched wild-type C57BL/6 mice were randomly divided into two groups: ad libitum fed and fasted. Mice were euthanized 12 or 48 hours after starvation. The proximal small bowel was harvested for morphologic analysis. Gut epithelial cell proliferation was detected using immunohistochemical staining for proliferating cell nuclear antigen (PCNA), and apoptosis was identified using terminal deoxyuridine nick-end labeling (TUNEL) staining. Results Aged IL-1R knockout mice were larger than aged-matched wild-type mice (p<0.05). Proximal gut mucosal height and mucosal cell number were not different between aged IL-1R knockout and wild-type groups. The apoptosis index in gut epithelial cells was higher in fed IL-1R knockout versus wild-type mice (p<0.05), while no significant difference in cell proliferation between both groups. Mucosal atrophy was induced in both aged IL-1R knockout and wild-type groups by starvation (p<0.05), however, aged IL-1R knockout mice experienced greater losses in proximal gut weight, mucosal length, and corresponding cell number than did wild-type mice at the 12-hour time point (p<0.05). The apoptosis index in gut epithelial cells significantly increased in both groups after starvation (p<0.05). Starvation decreased cell proliferation in IL-1R knockout mice (p<0.05), but not in wild-type mice. Conclusions The response in aged IL-1R knockout mice differs from wild-type mice in that starvation increases atrophy and is associated with decreased cell proliferation rather than increased apoptosis. PMID:20605606

  15. Spacer conformation in biologically active molecules. Part 2. Structure and conformation of 4-[2-(diphenylmethylamino)ethyl]-1-(2-methoxyphenyl) piperazine and its diphenylmethoxy analog—potential 5-HT 1A receptor ligands

    NASA Astrophysics Data System (ADS)

    Karolak-Wojciechowska, J.; Fruziński, A.; Czylkowski, R.; Paluchowska, M. H.; Mokrosz, M. J.

    2003-09-01

    As a part of studies on biologically active molecule structures with aliphatic linking chain, the structures of 4-[2-diphenylmethylamino)ethyl]-1-(2-methoxyphenyl)piperazine dihydrochloride ( 1) and 4-[2-diphenylmethoxy)ethyl]-1-(2-methoxyphenyl)piperazine fumarate ( 2) have been reported. In both compounds, four atomic non-all-carbons linking chains (N)C-C-X-C are present. The conformation of that linking spacer depends on the nature of the X-atom. The preferred conformation for chain with XNH has been found to be fully extended while for that with XO—the bend one. It was confirmed by conformational calculations (strain energy distribution and random search) and crystallographic data, including statistics from CCDC.

  16. Freud-2/CC2D1B mediates dual repression of the serotonin-1A receptor gene.

    PubMed

    Hadjighassem, Mahmoud R; Galaraga, Kimberly; Albert, Paul R

    2011-01-01

    The serotonin-1A (5-HT1A) receptor functions as a pre-synaptic autoreceptor in serotonin neurons that regulates their activity, and is also widely expressed on non-serotonergic neurons as a post-synaptic heteroreceptor to mediate serotonin action. The 5-HT1A receptor gene is strongly repressed by a dual repressor element (DRE), which is recognized by two proteins: Freud-1/CC2D1A and another unknown protein. Here we identify mouse Freud-2/CC2D1B as the second repressor of the 5-HT1A-DRE. Freud-2 shares 50% amino acid identity with Freud-1, and contains conserved structural domains. Mouse Freud-2 bound specifically to the rat 5-HT1A-DRE adjacent to, and partially overlapping, the Freud-1 binding site. By supershift assay using nuclear extracts from L6 myoblasts, Freud-2-DRE complexes were distinguished from Freud-1-DRE complexes. Freud-2 mRNA and protein were detected throughout mouse brain and peripheral tissues. Freud-2 repressed 5-HT1A promoter-reporter constructs in a DRE-dependent manner in non-neuronal (L6) or 5-HT1A-expressing neuronal (NG108-15, RN46A) cell models. In NG108-15 cells, knockdown of Freud-2 using a specific short-interfering RNA reduced endogenous Freud-2 protein levels and decreased Freud-2 bound to the 5-HT1A-DRE as detected by chromatin immunoprecipitation assay, but increased 5-HT1A promoter activity and 5-HT1A protein levels. Taken together, these data show that Freud-2 is the second component that, with Freud-1, mediates dual repression of the 5-HT1A receptor gene at the DRE.

  17. Prostanoids and inflammation: a new concept arising from receptor knockout mice.

    PubMed

    Narumiya, Shuh

    2009-10-01

    Prostanoids including various types of prostaglandins and thromboxanes are arachidonate metabolites produced and released in response to a variety of physiological and pathological stimuli and function to maintain the body homeostasis. Since cyclooxygenase, the enzyme initiating their biosynthesis, is inhibited by aspirin-like antipyretic, anti-inflammatory, and analgesic drugs, contribution of prostanoids to acute inflammation such as fever generation, pain sensitization, and inflammatory swelling has been recognized very early. On the other hand, since aspirin-like drugs generally show little effects on allergy and immunity, it has been believed that prostanoids play little roles in these processes. Prostanoids act on a family of G-protein-coupled receptors designated PGD receptor, PGE receptor subtypes EP1-EP4, PGF receptor, PGI receptor, and TX receptor to elicit their actions. Studies using mice deficient in each of these receptors have revealed that prostanoids indeed function in the above aspirin-sensitive processes. However, these studies have also revealed that prostanoids exert both pro-inflammatory and anti-inflammatory actions not only by acting as mediators of acute inflammation but also by regulating gene expression in mesenchymal and epithelial cells at inflammatory site. Such dual actions of prostanoids are frequently seen in immune and allergic reactions, where different type of prostanoids and their receptors often exert opposite actions in a single process. Thus, a new concept on the role of prostanoids in inflammation has arisen from studies using the receptor knockout mice. PMID:19609495

  18. Interleukin-15 affects serotonin system and exerts antidepressive effects through IL15Rα receptor

    PubMed Central

    Wu, Xiaojun; Hsuchou, Hung; Kastin, Abba J.; He, Yi; Khan, Reas S.; Stone, Kirsten P.; Cash, Michael S.; Pan, Weihong

    2010-01-01

    Summary Contrary to the reduction of depressive-like behavior observed in several strains of cytokine receptor knockout mice, mice lacking the specific receptor for interleukin (IL)-15 showed increased immobility in tail suspension and modified forced swimming tests. There was also a reduction in social interactions. The hippocampus of the IL15Rα knockout mice had decreased mRNA for 5-HT1A, increased mRNA for 5-HT2C, and region-specific changes of serotonin reuptake transporter (SERT) immunoreactivity. Fluoxetine (the classic antidepressant Prozac, which inhibits 5-HT2C and SERT) reduced the immobility of the IL15Rα knockout mice in comparison with their pretreatment baseline. Together with the unchanged performance of the IL15Rα knockout mice on the rotarod, this response to fluoxetine indicates that the immobility reflects depression. Wildtype mice responded to IL15 treatment with improvement of immobility induced by forced swimming, whereas the knockout mice failed to respond. Thus, the cognate IL15 receptor is necessary for the antidepressive activity of IL15. In ex-vivo studies, IL15 decreased synaptosomal uptake of 5-HT, and modulated the expression of 5-HT2C and SERT in cultured neurons in a dose- and time-dependent manner. Thus, the effect of IL15 on serotonin transmission may underlie the depressive-like behavior of IL15Rα knockout mice. We speculate that IL15 is essential to maintain neurochemical homeostasis and thereby plays a role in preventing neuropsychiatric symptoms. PMID:20724079

  19. 5-Hydroxytryptamine 1A receptors in the dorsomedial hypothalamus connected to dorsal raphe nucleus inputs modulate defensive behaviours and mediate innate fear-induced antinociception.

    PubMed

    Biagioni, Audrey Franceschi; de Oliveira, Rithiele Cristina; de Oliveira, Ricardo; da Silva, Juliana Almeida; dos Anjos-Garcia, Tayllon; Roncon, Camila Marroni; Corrado, Alexandre Pinto; Zangrossi, Hélio; Coimbra, Norberto Cysne

    2016-03-01

    The dorsal raphe nucleus (DRN) is an important brainstem source of 5-hydroxytryptamine (5-HT), and 5-HT plays a key role in the regulation of panic attacks. The aim of the present study was to determine whether 5-HT1A receptor-containing neurons in the medial hypothalamus (MH) receive neural projections from DRN and to then determine the role of this neural substrate in defensive responses. The neurotracer biotinylated dextran amine (BDA) was iontophoretically microinjected into the DRN, and immunohistochemical approaches were then used to identify 5HT1A receptor-labelled neurons in the MH. Moreover, the effects of pre-treatment of the dorsomedial hypothalamus (DMH) with 8-OH-DPAT and WAY-100635, a 5-HT1A receptor agonist and antagonist, respectively, followed by local microinjections of bicuculline, a GABAA receptor antagonist, were investigated. We found that there are many projections from the DRN to the perifornical lateral hypothalamus (PeFLH) but also to DMH and ventromedial (VMH) nuclei, reaching 5HT1A receptor-labelled perikarya. DMH GABAA receptor blockade elicited defensive responses that were followed by antinociception. DMH treatment with 8-OH-DPAT decreased escape responses, which strongly suggests that the 5-HT1A receptor modulates the defensive responses. However, DMH treatment with WAY-100635 failed to alter bicuculline-induced defensive responses, suggesting that 5-HT exerts a phasic influence on 5-HT1A DMH neurons. The activation of the inhibitory 5-HT1A receptor had no effect on antinociception. However, blockade of the 5-HT1A receptor decreased fear-induced antinociception. The present data suggest that the ascending pathways from the DRN to the DMH modulate panic-like defensive behaviours and mediate antinociceptive phenomenon by recruiting 5-HT1A receptor in the MH. PMID:26749090

  20. Quantification of beta adrenergic receptor subtypes in beta-arrestin knockout mouse airways.

    PubMed

    Hegde, Akhil; Strachan, Ryan T; Walker, Julia K L

    2015-01-01

    In allergic asthma Beta 2 adrenergic receptors (β2ARs) are important mediators of bronchorelaxation and, paradoxically, asthma development. This contradiction is likely due to the activation of dual signaling pathways that are downstream of G proteins or β-arrestins. Our group has recently shown that β-arrestin-2 acts in its classical role to desensitize and constrain β2AR-induced relaxation of both human and murine airway smooth muscle. To assess the role of β-arrestins in regulating β2AR function in asthma, we and others have utilized β-arrestin-1 and -2 knockout mice. However, it is unknown if genetic deletion of β-arrestins in these mice influences β2AR expression in the airways. Furthermore, there is lack of data on compensatory expression of βAR subtypes when either of the β-arrestins is genetically deleted, thus necessitating a detailed βAR subtype expression study in these β-arrestin knockout mice. Here we standardized a radioligand binding methodology to characterize and quantitate βAR subtype distribution in the airway smooth muscle of wild-type C57BL/6J and β-arrestin-1 and β-arrestin-2 knockout mice. Using complementary competition and single-point saturation binding assays we found that β2ARs predominate over β1ARs in the whole lung and epithelium-denuded tracheobronchial smooth muscle of C57BL/6J mice. Quantification of βAR subtypes in β-arrestin-1 and β-arrestin-2 knockout mouse lung and epithelium-denuded tracheobronchial tissue showed that, similar to the C57BL/6J mice, both knockouts display a predominance of β2AR expression. These data provide further evidence that β2ARs are expressed in greater abundance than β1ARs in the tracheobronchial smooth muscle and that loss of either β-arrestin does not significantly affect the expression or relative proportions of βAR subtypes. As β-arrestins are known to modulate β2AR function, our analysis of βAR subtype expression in β-arrestin knockout mice airways sets a reference

  1. Pituitary gonadotrophic hormone synthesis, secretion, subunit gene expression and cell structure in normal and follicle-stimulating hormone β knockout, follicle-stimulating hormone receptor knockout, luteinising hormone receptor knockout, hypogonadal and ovariectomised female mice.

    PubMed

    Abel, M H; Widen, A; Wang, X; Huhtaniemi, I; Pakarinen, P; Kumar, T R; Christian, H C

    2014-11-01

    To investigate the relationship between gonadotroph function and ultrastructure, we have compared, in parallel in female mice, the effects of several different mutations that perturb the hypothalamic-pituitary-gonadal axis. Specifically, serum and pituitary gonadotrophin concentrations, gonadotrophin gene expression, gonadotroph structure and number were measured. Follicle-stimulating hormone β knockout (FSHβKO), follicle-stimulating hormone receptor knockout (FSHRKO), luteinising hormone receptor knockout (LuRKO), hypogonadal (hpg) and ovariectomised mice were compared with control wild-type or heterozygote female mice. Serum levels of LH were elevated in FSHβKO and FSHRKO compared to heterozygote females, reflecting the likely decreased oestrogen production in KO females, as demonstrated by the threadlike uteri and acyclicity. As expected, there was no detectable FSH in the serum or pituitary and an absence of expression of the FSHβ subunit gene in FSHβKO mice. However, there was a significant increase in expression of the FSHβ and LHβ subunit genes in FSHRKO female mice. The morphology of FSHβKO and FSHRKO gonadotrophs was not significantly different from the control, except that secretory granules in FSHRKO gonadotrophs were larger in diameter. In LuRKO and ovariectomised mice, stimulation of LHβ and FSHβ mRNA, as well as serum protein concentrations, were reflected in subcellular changes in gonadotroph morphology, including more dilated rough endoplasmic reticula and fewer, larger secretory granules. In the gonadotophin-releasing hormone deficient hpg mouse, gonadotrophin mRNA and protein levels were significantly lower than in control mice and gonadotrophs were correspondingly smaller with less abundant endoplasmic reticula and reduced numbers of secretory granules. In summary, major differences in pituitary content and serum concentrations of the gonadotrophins LH and FSH were found between control and mutant female mice. These changes were

  2. Parkin expression profile in dopamine d3 receptor knock-out mice brains.

    PubMed

    D'Agata, Velia; Tiralongo, Adriana; Castorina, Alessandro; Leggio, Gian Marco; Micale, Vincenzo; Carnazza, Maria Luisa; Drago, Filippo

    2009-02-01

    Patients affected by autosomic recessive juvenile parkinsonism (ARJP) exhibit parkin gene mutations with brain decrease in dopamine D2/D3 binding sites. To date, there are no data indicating whether the reduction in dopamine D3 receptors (DRD3) may be associated with the expression of specific parkin variants. In the present study we investigated parkin expression profile in DRD3 knock-out mice brains. RT-PCR analysis was performed to assess qualitative changes in parkin isoforms' distribution pattern and in exons' expression both in wild type controls and dopamine D3 receptor's knock-out mice. Real-time PCR was performed to quantify single exons mRNA. Results demonstrated that exons 1, 2, 4, 6, 7, 8, were more expressed in wild type compared to dopamine D3 receptor KO mice brains while some other (3, 9, 10) were lower expressed. The expression levels of exons 5, 11 and 12 did not change in both animal groups. Our analysis was confirmed by western blot, which showed that parkin protein levels were influenced by the absence of DRD3.

  3. HSL-knockout mouse testis exhibits class B scavenger receptor upregulation and disrupted lipid raft microdomains.

    PubMed

    Casado, María Emilia; Huerta, Lydia; Ortiz, Ana Isabel; Pérez-Crespo, Mirian; Gutiérrez-Adán, Alfonso; Kraemer, Fredric B; Lasunción, Miguel Ángel; Busto, Rebeca; Martín-Hidalgo, Antonia

    2012-12-01

    There is a tight relationship between fertility and changes in cholesterol metabolism during spermatogenesis. In the testis, class B scavenger receptors (SR-B) SR-BI, SR-BII, and LIMP II mediate the selective uptake of cholesterol esters from HDL, which are hydrolyzed to unesterified cholesterol by hormone-sensitive lipase (HSL). HSL is critical because HSL knockout (KO) male mice are sterile. The aim of the present work was to determine the effects of the lack of HSL in testis on the expression of SR-B, lipid raft composition, and related cell signaling pathways. HSL-KO mouse testis presented altered spermatogenesis associated with decreased sperm counts, sperm motility, and infertility. In wild-type (WT) testis, HSL is expressed in elongated spermatids; SR-BI, in Leydig cells and spermatids; SR-BII, in spermatocytes and spermatids but not in Leydig cells; and LIMP II, in Sertoli and Leydig cells. HSL knockout male mice have increased expression of class B scavenger receptors, disrupted caveolin-1 localization in lipid raft plasma membrane microdomains, and activated phospho-ERK, phospho-AKT, and phospho-SRC in the testis, suggesting that class B scavenger receptors are involved in cholesterol ester uptake for steroidogenesis and spermatogenesis in the testis.

  4. Brain Serotonin 1A Receptor Binding as a Predictor of Treatment Outcome in Major Depressive Disorder

    PubMed Central

    Miller, Jeffrey M.; Hesselgrave, Natalie; Ogden, R. Todd; Zanderigo, Francesca; Oquendo, Maria A.; Mann, J. John; Parsey, Ramin V.

    2013-01-01

    Background We previously reported higher serotonin 1A receptor (5-HT1A) binding in subjects with major depressive disorder (MDD) during a major depressive episode using positron emission tomography imaging with [11C]WAY-100635. 5-HT1A receptor binding is also associated with treatment outcome after nonstandardized antidepressant treatment. We examined whether pretreatment 5-HT1A binding is associated with treatment outcome following standardized escitalopram treatment in MDD. We also compared 5-HT1A binding between all MDD subjects in this cohort and a sample of healthy control subjects. Methods Twenty-four MDD subjects in a current major depressive episode and 51 previously studied healthy control subjects underwent positron emission tomography scanning with [11C]WAY-100635, acquiring a metabolite-corrected arterial input function and free-fraction measurement to estimate 5-HT1A binding potential (BPF = Bmax/KD, where Bmax = available receptors and KD = dissociation constant). Major depressive disorder subjects then received 8 weeks of treatment with escitalopram; remission was defined as a posttreatment 24-item Hamilton Depression Rating Scale <10 and ≥50% reduction in Hamilton Depression Rating Scale. Results Remitters to escitalopram had 33% higher baseline 5-HT1A binding in the raphe nuclei than nonremitters (p = .047). Across 12 cortical and subcortical regions, 5-HT1A binding did not differ between remitters and nonremitters (p = .86). Serotonin 1A receptor binding was higher in MDD than control subjects across all regions (p = .0003). Remitters did not differ from nonremitters in several relevant clinical measures. Conclusions Elevated 5-HT1A binding in raphe nuclei is associated with subsequent remission with the selective serotonin reuptake inhibitor escitalopram; this is consistent with data from a separate cohort receiving naturalistic antidepressant treatment. We confirmed our previous findings of higher 5-HT1A binding in current MDD compared with

  5. Altered hippocampal expression of glutamate receptors and transporters in GRM2 and GRM3 knockout mice.

    PubMed

    Lyon, Louisa; Kew, James N C; Corti, Corrado; Harrison, Paul J; Burnet, Philip W J

    2008-11-01

    Group II metabotropic glutamate receptors (mGluR2 and mGluR3, also called mGlu2 and mGlu3, encoded by GRM2 and GRM3, respectively) are therapeutic targets for several psychiatric disorders. GRM3 may also be a schizophrenia susceptibility gene. mGluR2-/- and mGluR3-/- mice provide the only unequivocal means to differentiate between these receptors, yet interpretation of in vivo findings may be complicated by secondary effects on expression of other genes. To address this issue, we examined the expression of NMDA receptor subunits (NR1, NR2A, NR2B) and glutamate transporters (EAAT1-3), as well as the remaining group II mGluR, in the hippocampus of mGluR2-/- and mGluR3-/- mice, compared with wild-type controls. mGluR2 mRNA was increased in mGluR3-/- mice, and vice versa. NR2A mRNA was increased in both knockout mice. EAAT1 (GLAST) mRNA and protein, and EAAT2 (GLT-1) protein, were reduced in mGluR3-/- mice, whereas EAAT3 (EAAC1) mRNA was decreased in mGluR2-/- mice. Transcripts for NR1 and NR2B were unchanged. The findings show a compensatory upregulation of the remaining group II metabotropic glutamate receptor in the knockout mice. Upregulation of NR2A expression suggests modified NMDA receptor signaling in mGluR2-/- and mGluR3-/- mice, and downregulation of glutamate transporter expression suggests a response to altered synaptic glutamate levels. The results show a mutual interplay between mGluR2 and mGluR3, and also provide a context in which to interpret behavioral and electrophysiological results in these mice. PMID:18720515

  6. Raphe serotonin neuron-specific oxytocin receptor knockout reduces aggression without affecting anxiety-like behavior in male mice only.

    PubMed

    Pagani, J H; Williams Avram, S K; Cui, Z; Song, J; Mezey, É; Senerth, J M; Baumann, M H; Young, W S

    2015-02-01

    Serotonin and oxytocin influence aggressive and anxiety-like behaviors, though it is unclear how the two may interact. That the oxytocin receptor is expressed in the serotonergic raphe nuclei suggests a mechanism by which the two neurotransmitters may cooperatively influence behavior. We hypothesized that oxytocin acts on raphe neurons to influence serotonergically mediated anxiety-like, aggressive and parental care behaviors. We eliminated expression of the oxytocin receptor in raphe neurons by crossing mice expressing Cre recombinase under control of the serotonin transporter promoter (Slc6a4) with our conditional oxytocin receptor knockout line. The knockout mice generated by this cross are normal across a range of behavioral measures: there are no effects for either sex on locomotion in an open-field, olfactory habituation/dishabituation or, surprisingly, anxiety-like behaviors in the elevated O and plus mazes. There was a profound deficit in male aggression: only one of 11 raphe oxytocin receptor knockouts showed any aggressive behavior, compared to 8 of 11 wildtypes. In contrast, female knockouts displayed no deficits in maternal behavior or aggression. Our results show that oxytocin, via its effects on raphe neurons, is a key regulator of resident-intruder aggression in males but not maternal aggression. Furthermore, this reduction in male aggression is quite different from the effects reported previously after forebrain or total elimination of oxytocin receptors. Finally, we conclude that when constitutively eliminated, oxytocin receptors expressed by serotonin cells do not contribute to baseline anxiety-like behaviors or maternal care.

  7. Raphe serotonin neuron-specific oxytocin receptor knockout reduces aggression without affecting anxiety-like behavior in male mice only

    PubMed Central

    Pagani, Jerome H.; Williams Avram, Sarah K.; Cui, Zhenzhong; Song, June; Mezey, Éva; Senerth, Julia M.; Baumann, Michael H.; Young, W. Scott

    2015-01-01

    Serotonin and oxytocin influence aggressive and anxiety-like behaviors, though it is unclear how the two may interact. That the oxytocin receptor is expressed in the serotonergic raphe nuclei suggests a mechanism by which the two neurotransmitters may cooperatively influence behavior. We hypothesized that oxytocin acts on raphe neurons to influence serotonergically-mediated anxiety-like, aggressive and parental care behaviors. We eliminated expression of the oxytocin receptor in raphe neurons by crossing mice expressing Cre recombinase under control of the serotonin transporter promoter (Slc6a4) with our conditional oxytocin receptor knockout line. The knockout mice generated by this cross are normal across a range of behavioral measures: there are no effects for either sex on locomotion in an open-field, olfactory habituation/dishabituation or, surprisingly, anxiety-like behaviors in the elevated O and plus mazes. There was a profound deficit in male aggression: only one of 11 raphe oxytocin receptor knockouts showed any aggressive behavior, compared to eight of 11 wildtypes. In contrast, female knockouts displayed no deficits in maternal behavior or aggression. Our results show that oxytocin, via its effects on raphe neurons, is a key regulator of resident-intruder aggression in males but not maternal aggression. Furthermore, this reduction in male aggression is quite different from the effects reported previously after forebrain or total elimination of oxytocin receptors. Finally, we conclude that when constitutively eliminated, oxytocin receptors expressed by serotonin cells do not contribute to baseline anxiety-like behaviors or maternal care. PMID:25677455

  8. Uptake and catabolism of modified LDL in scavenger-receptor class A type I/II knock-out mice.

    PubMed Central

    Van Berkel, T J; Van Velzen, A; Kruijt, J K; Suzuki, H; Kodama, T

    1998-01-01

    The liver is the major organ responsible for the uptake of modified low-density lipoprotein (LDL) from the blood circulation, with endothelial and Kupffer cells as major cellular uptake sites. Scavenger-receptors, which include various classes, are held responsible for this uptake. Mice deficient in scavenger-receptor class A types I and II were created and the fate of acetylated LDL (Ac-LDL) in vivo and its interaction with liver endothelial, Kupffer and peritoneal macrophages was characterized. Surprisingly, the decay in vivo (t12 < 2 min), tissue distribution and liver uptake (at 5 min it was 77.4 +/- 4.6% of the injected dose) of Ac-LDL in the knock-out mice were not significantly different from control mice (t12 < 2 min and liver uptake 79.1 +/- 4.6% of the injected dose). A separation of mice liver cells into parenchymal, endothelial and Kupffer cells 10 min after injection of Ac-LDL indicated that in both control and knock-out mice the liver endothelial cells were responsible for more than 70% of the liver uptake. Both in control and knock-out mice, preinjection of polyinosinic acid (poly I, 200 microg) completely blocked the liver uptake, indicating that both in control and knock-out mice the scavenger-receptors are sensitive to poly I. Preinjection of suboptimal poly I concentrations (20 and 50 microg) provided evidence that the serum decay and liver uptake of Ac-LDL is more readily inhibited in the knock-out mice as compared with the control mice, indicating less efficient removal of Ac-LDL in vivo in the knock-out mice under these conditions. Studies in vitro with isolated liver endothelial and Kupffer cells from knock-out mice indicate that the cell association of Ac-LDL during 2 h at 37 degrees C is 50 and 53% of the control, respectively, whereas the degradation reaches values of 58 and 63%. For peritoneal macrophages from knock-out mice the cell association of Ac-LDL was identical to the control mice whereas the Ac-LDL degradation in cells from the

  9. Comparative effects of chlorpyrifos in wild type and cannabinoid Cb1 receptor knockout mice

    SciTech Connect

    Baireddy, Praveena; Liu, Jing; Hinsdale, Myron; Pope, Carey

    2011-11-15

    Endocannabinoids (eCBs) modulate neurotransmission by inhibiting the release of a variety of neurotransmitters. The cannabinoid receptor agonist WIN 55.212-2 (WIN) can modulate organophosphorus (OP) anticholinesterase toxicity in rats, presumably by inhibiting acetylcholine (ACh) release. Some OP anticholinesterases also inhibit eCB-degrading enzymes. We studied the effects of the OP insecticide chlorpyrifos (CPF) on cholinergic signs of toxicity, cholinesterase activity and ACh release in tissues from wild type (+/+) and cannabinoid CB1 receptor knockout (-/-) mice. Mice of both genotypes (n = 5-6/treatment group) were challenged with CPF (300 mg/kg, 2 ml/kg in peanut oil, sc) and evaluated for functional and neurochemical changes. Both genotypes exhibited similar cholinergic signs and cholinesterase inhibition (82-95% at 48 h after dosing) in cortex, cerebellum and heart. WIN reduced depolarization-induced ACh release in vitro in hippocampal slices from wild type mice, but had no effect in hippocampal slices from knockouts or in striatal slices from either genotype. Chlorpyrifos oxon (CPO, 100 {mu}M) reduced release in hippocampal slices from both genotypes in vitro, but with a greater reduction in tissues from wild types (21% vs 12%). CPO had no significant in vitro effect on ACh release in striatum. CPF reduced ACh release in hippocampus from both genotypes ex vivo, but reduction was again significantly greater in tissues from wild types (52% vs 36%). In striatum, CPF led to a similar reduction (20-23%) in tissues from both genotypes. Thus, while CB1 deletion in mice had little influence on the expression of acute toxicity following CPF, CPF- or CPO-induced changes in ACh release appeared sensitive to modulation by CB1-mediated eCB signaling in a brain-regional manner. -- Highlights: Black-Right-Pointing-Pointer C57Bl/6 mice showed dose-related cholinergic toxicity following subcutaneous chlorpyrifos exposure. Black-Right-Pointing-Pointer Wild type and

  10. Effect of P2X7 Receptor Knockout on AQP-5 Expression of Type I Alveolar Epithelial Cells

    PubMed Central

    Ebeling, Georg; Bläsche, Robert; Hofmann, Falk; Augstein, Antje; Kasper, Michael; Barth, Kathrin

    2014-01-01

    P2X7 receptors, ATP-gated cation channels, are specifically expressed in alveolar epithelial cells. The pathophysiological function of this lung cell type, except a recently reported putative involvement in surfactant secretion, is unknown. In addition, P2X7 receptor-deficient mice show reduced inflammation and lung fibrosis after exposure with bleomycin. To elucidate the role of the P2X7 receptor in alveolar epithelial type I cells we characterized the pulmonary phenotype of P2X7 receptor knockout mice by using immunohistochemistry, western blot analysis and real-time RT PCR. No pathomorphological signs of fibrosis were found. Results revealed, however, a remarkable loss of aquaporin-5 protein and mRNA in young knockout animals. Additional in vitro experiments with bleomycin treated precision cut lung slices showed a greater sensitivity of the P2X7 receptor knockout mice in terms of aquaporin-5 reduction as wild type animals. Finally, P2X7 receptor function was examined by using the alveolar epithelial cell lines E10 and MLE-12 for stimulation experiments with bleomycin. The in vitro activation of P2X7 receptor was connected with an increase of aquaporin-5, whereas the inhibition of the receptor with oxidized ATP resulted in down regulation of aquaporin-5. The early loss of aquaporin-5 which can be found in different pulmonary fibrosis models does not implicate a specific pathogenetic role during fibrogenesis. PMID:24941004

  11. Immune malfunction in the GPR39 zinc receptor of knockout mice: Its relationship to depressive disorder.

    PubMed

    Młyniec, Katarzyna; Trojan, Ewa; Ślusarczyk, Joanna; Głombik, Katarzyna; Basta-Kaim, Agnieszka; Budziszewska, Bogusława; Skrzeszewski, Jakub; Siwek, Agata; Holst, Birgitte; Nowak, Gabriel

    2016-02-15

    Depression is a serious psychiatric disorder affecting not only the monaminergic, glutamatergic, and GABAergic neurosystems, but also the immune system. Patients suffering from depression show disturbance in the immune parameters as well as increased susceptibility to infections. Zinc is well known as an anti-inflammatory agent, and its link with depression has been proved, zinc deficiency causing depression- and anxiety-like behavior with immune malfunction. It has been discovered that trace-element zinc acts as a neurotransmitter in the central nervous system via zinc receptor GPR39. In this study we investigated whether GPR39 knockout would cause depressive-like behavior as measured by the forced swim test, and whether these changes would coexist with immune malfunction. In GPR39 knockout mice versus a wild-type control we found: i) depressive-like behavior; ii) significantly reduced thymus weight; (iii) reduced cell viability of splenocytes; iv) reduced proliferative response of splenocytes; and v) increased IL-6 production of splenocytes after ConA stimulation and decreased IL-1b and IL-6 release after LPS stimulation. The results indicate depressive-like behavior in GPR39 KO animals with an immune response similar to that observed in depressive disorder. Here for the first time we show immunological changes under GPR39-deficient conditions. PMID:26857489

  12. Myeloid Deletion of α1AMPK Exacerbates Atherosclerosis in LDL Receptor Knockout (LDLRKO) Mice.

    PubMed

    Cao, Qiang; Cui, Xin; Wu, Rui; Zha, Lin; Wang, Xianfeng; Parks, John S; Yu, Liqing; Shi, Hang; Xue, Bingzhong

    2016-06-01

    Macrophage inflammation marks all stages of atherogenesis, and AMPK is a regulator of macrophage inflammation. We therefore generated myeloid α1AMPK knockout (MAKO) mice on the LDL receptor knockout (LDLRKO) background to investigate whether myeloid deletion of α1AMPK exacerbates atherosclerosis. When fed an atherogenic diet, MAKO/LDLRKO mice displayed exacerbated atherosclerosis compared with LDLRKO mice. To determine the underlying pathophysiological pathways, we characterized macrophage inflammation/chemotaxis and lipid/cholesterol metabolism in MAKO/LDLRKO mice. Myeloid deletion of α1AMPK increased macrophage inflammatory gene expression and enhanced macrophage migration and adhesion to endothelial cells. Remarkably, MAKO/LDLRKO mice also displayed higher composition of circulating chemotaxically active Ly-6C(high) monocytes, enhanced atherosclerotic plaque chemokine expression, and monocyte recruitment into plaques, leading to increased atherosclerotic plaque macrophage content and inflammation. MAKO/LDLRKO mice also exhibited higher plasma LDL and VLDL cholesterol content, increased circulating apolipoprotein B (apoB) levels, and higher liver apoB expression. We conclude that macrophage α1AMPK deficiency promotes atherogenesis in LDLRKO mice and is associated with enhanced macrophage inflammation and hypercholesterolemia and that macrophage α1AMPK may serve as a therapeutic target for prevention and treatment of atherosclerosis. PMID:26822081

  13. Immune malfunction in the GPR39 zinc receptor of knockout mice: Its relationship to depressive disorder.

    PubMed

    Młyniec, Katarzyna; Trojan, Ewa; Ślusarczyk, Joanna; Głombik, Katarzyna; Basta-Kaim, Agnieszka; Budziszewska, Bogusława; Skrzeszewski, Jakub; Siwek, Agata; Holst, Birgitte; Nowak, Gabriel

    2016-02-15

    Depression is a serious psychiatric disorder affecting not only the monaminergic, glutamatergic, and GABAergic neurosystems, but also the immune system. Patients suffering from depression show disturbance in the immune parameters as well as increased susceptibility to infections. Zinc is well known as an anti-inflammatory agent, and its link with depression has been proved, zinc deficiency causing depression- and anxiety-like behavior with immune malfunction. It has been discovered that trace-element zinc acts as a neurotransmitter in the central nervous system via zinc receptor GPR39. In this study we investigated whether GPR39 knockout would cause depressive-like behavior as measured by the forced swim test, and whether these changes would coexist with immune malfunction. In GPR39 knockout mice versus a wild-type control we found: i) depressive-like behavior; ii) significantly reduced thymus weight; (iii) reduced cell viability of splenocytes; iv) reduced proliferative response of splenocytes; and v) increased IL-6 production of splenocytes after ConA stimulation and decreased IL-1b and IL-6 release after LPS stimulation. The results indicate depressive-like behavior in GPR39 KO animals with an immune response similar to that observed in depressive disorder. Here for the first time we show immunological changes under GPR39-deficient conditions.

  14. Estrogens and Spermiogenesis: New Insights from Type 1 Cannabinoid Receptor Knockout Mice

    PubMed Central

    Cacciola, Giovanna; Chioccarelli, Teresa; Fasano, Silvia; Pierantoni, Riccardo; Cobellis, Gilda

    2013-01-01

    Spermatogenesis is a complex mechanism which allows the production of male gametes; it consists of mitotic, meiotic, and differentiation phases. Spermiogenesis is the terminal differentiation process during which haploid round spermatids undergo several biochemical and morphological changes, including extensive remodelling of chromatin and nuclear shape. Spermiogenesis is under control of endocrine, paracrine, and autocrine factors, like gonadotropins and testosterone. More recently, emerging pieces of evidence are suggesting that, among these factors, estrogens may have a role. To date, this is a matter of debate and concern because of the agonistic and antagonistic estrogenic effects that environmental chemicals may have on animal and human with damaging outcome on fertility. In this review, we summarize data which fuel this debate, with a particular attention to our recent results, obtained using type 1 cannabinoid receptor knockout male mice as animal model. PMID:24324492

  15. Interferon α/β receptor knockout mice as a model to study bluetongue virus infection.

    PubMed

    Ortego, Javier; de la Poza, Francisco; Marín-López, Alejandro

    2014-03-01

    Bluetongue is an arthropod-borne disease caused by a virus of the genus Orbivirus, the bluetongue virus (BTV), which affects ruminant livestock such as cattle, sheep, and goats and wild ruminants such as deer, and camelids. Recently, adult mice with gene knockouts of the interferon α/β receptor (IFNAR-/-) have been described as a model of lethal BTV infection. IFNAR(-/-) mice are highly susceptible to BTV-1, BTV-4 and BTV-8 infection when the virus is administered intravenously or subcutaneosuly. Disease progression and pathogenesis closely mimics signs of bluetongue disease in ruminants. In the present paper we review the studies where IFNAR(-/-) mice have been used as an animal model to study BTV transmission, pathogenesis, virulence, and protective efficacy of inactivated and new recombinant marker BTV vaccines. Furthermore, we report new data on protective efficacy of different strategies of BTV vaccination and also on induction of interferon α/β and proinflammatory immune responses in IFNAR(-/-) mice infected with BTV.

  16. [Upregulation of P2X3 receptors in dorsal root ganglion of TRPV1 knockout female mice].

    PubMed

    Fang, Xiao; Shi, Xiao-Han; Huang, Li-Bin; Rong, Wei-Fang; Ma, Bei

    2014-08-25

    The study was aimed to investigate the changes in mechanical pain threshold in the condition of chronic inflammatory pain after transient receptor potential vanilloid 1 (TRPV1) gene was knockout. Hind-paw intraplantar injection of complete freund's adjuvant (CFA, 20 μL) produced peripheral inflammation in wild-type and TRPV1 knockout female mice. The mechanical pain thresholds were measured during the 8 days after injection and pre-injection by using Von-Frey hair. Nine days after injection, mice were killed and the differences of expression of c-Fos and P2X3 receptor in the dorsal root ganglia (DRG) and spinal cord dorsal horn were examined by Western blotting between the two groups. Compared with that in wild-type mice, the mechanical pain threshold was increased significantly in TRPV1 knockout mice (P < 0.05); 3 days after CFA injection, the baseline mechanical pain threshold in the TRPV1 knockout mice group was significantly higher than that in the wild-type mice group (P < 0.05); The result of Western blotting showed that the expression of c-Fos protein both in DRG and spinal cord dorsal horn of TRPV1 knockout mice group was decreased significantly compared with that in wild-type mice group (P < 0.01, P < 0.05), while the expression of P2X3 receptor in DRG of TRPV1 knockout mice group was increased significantly compared with that in wild-type mice group (P < 0.05). Our findings indicate that TRPV1 may influence the peripheral mechanical pain threshold by mediating the expression of c-Fos protein both in DRG and spinal cord dorsal horn and changing the expression of P2X3 receptor in DRG.

  17. The restructuring of muscarinic receptor subtype gene transcripts in c-fos knock-out mice.

    PubMed

    Benes, Jan; Mravec, Boris; Kvetnansky, Richard; Myslivecek, Jaromir

    2013-05-01

    Although c-Fos plays a key role in intracellular signalling, the disruption of the c-fos gene has only minor consequences on the central nervous system (CNS) function. As muscarinic receptors (MR) play important roles in many CNS functions (attention, arousal, and cognition), the c-fos knock-out might be compensated through MR changes. The aim of this study was to evaluate changes in the M1-M5 MR mRNA in selected CNS areas: frontal, parietal, temporal and occipital cortex, striatum, hippocampus, hypothalamus and cerebellum (FC, PC, TC, OC, stria, hip, hypo, and crbl, respectively). Knocking out the c-fos gene changed the expression of MR in FC (reduced M1R, M4R and M5R expression), TC (increased M4R expression), OC (decreased M2R and M3R expression) and hippocampus (reduced M3R expression). Moreover, gender differences were observed in WT mice: increased expression of all M1-M5R in the FC in males and M1-M4R in the striatum in females. A detailed analysis of MR transcripts showed pre-existing correlations in the amount of MR-mRNA between specific regions. WT mice showed three major types of cortico-cortical correlations: fronto-occipital, temporo-parietal and parieto-occipital. The cortico-subcortical correlations involved associations between the FC, PC, TC and striatum. In KO mice, a substantial rearrangement of the correlation pattern was observed: only a temporo-parietal correlation and correlations between the FC and striatum remained, and a new correlation between the hypothalamus and cerebellum appeared. Thus, in addition to the previously described dopamine receptor restructuring, the restructuring of MR mRNA correlations reveals an additional mechanism for adaptation to the c-fos gene knockout.

  18. Knockout of NMDA receptors in parvalbumin interneurons recreates autism-like phenotypes.

    PubMed

    Saunders, John A; Tatard-Leitman, Valerie M; Suh, Jimmy; Billingslea, Eddie N; Roberts, Timothy P; Siegel, Steven J

    2013-04-01

    Autism is a disabling neurodevelopmental disorder characterized by social deficits, language impairment, and repetitive behaviors with few effective treatments. New evidence suggests that autism has reliable electrophysiological endophenotypes and that these measures may be caused by n-methyl-d-aspartic acid receptor (NMDAR) disruption on parvalbumin (PV)-containing interneurons. These findings could be used to create new translational biomarkers. Recent developments have allowed for cell-type selective knockout of NMDARs in order to examine the perturbations caused by disrupting specific circuits. This study examines several electrophysiological and behavioral measures disrupted in autism using a PV-selective reduction in NMDA R1 subunit. Mouse electroencephalograph (EEG) was recorded in response to auditory stimuli. Event-related potential (ERP) component amplitude and latency analysis, social testing, and premating ultrasonic vocalizations (USVs) recordings were performed. Correlations were examined between the ERP latency and behavioral measures. The N1 ERP latency was delayed, sociability was reduced, and mating USVs were impaired in PV-selective NMDA Receptor 1 Knockout (NR1 KO) as compared with wild-type mice. There was a significant correlation between N1 latency and sociability but not between N1 latency and premating USV power or T-maze performance. The increases in N1 latency, impaired sociability, and reduced vocalizations in PV-selective NR1 KO mice mimic similar changes found in autism. Electrophysiological changes correlate to reduced sociability, indicating that the local circuit mechanisms controlling N1 latency may be utilized in social function. Therefore, we propose that behavioral and electrophysiological alterations in PV-selective NR1 KO mice may serve as a useful model for therapeutic development in autism. Autism Res 2013, 6: 69-77. © 2013 International Society for Autism Research, Wiley Periodicals, Inc.

  19. Conditional Knockout of NMDA Receptors in Dopamine Neurons Prevents Nicotine-Conditioned Place Preference

    PubMed Central

    Phillip Wang, Lei; Li, Fei; Shen, Xiaoming; Tsien, Joe Z.

    2010-01-01

    Nicotine from smoking tobacco produces one of the most common forms of addictive behavior and has major societal and health consequences. It is known that nicotine triggers tobacco addiction by activating nicotine acetylcholine receptors (nAChRs) in the midbrain dopaminergic reward system, primarily via the ventral tegmental area. Heterogeneity of cell populations in the region has made it difficult for pharmacology-based analyses to precisely assess the functional significance of glutamatergic inputs to dopamine neurons in nicotine addiction. By generating dopamine neuron-specific NR1 knockout mice using cre/loxP-mediated method, we demonstrate that genetic inactivation of the NMDA receptors in ventral tegmental area dopamine neurons selectively prevents nicotine-conditioned place preference. Interestingly, the mutant mice exhibit normal performances in the conditioned place aversion induced by aversive air puffs. Therefore, this selective effect on addictive drug-induced reinforcement behavior suggests that NMDA receptors in the dopamine neurons are critical for the development of nicotine addiction. PMID:20062537

  20. Brain Region-Specific Effects of cGMP-Dependent Kinase II Knockout on AMPA Receptor Trafficking and Animal Behavior

    ERIC Educational Resources Information Center

    Kim, Seonil; Pick, Joseph E.; Abera, Sinedu; Khatri, Latika; Ferreira, Danielle D. P.; Sathler, Matheus F.; Morison, Sage L.; Hofmann, Franz; Ziff, Edward B.

    2016-01-01

    Phosphorylation of GluA1, a subunit of AMPA receptors (AMPARs), is critical for AMPAR synaptic trafficking and control of synaptic transmission. cGMP-dependent protein kinase II (cGKII) mediates this phosphorylation, and cGKII knockout (KO) affects GluA1 phosphorylation and alters animal behavior. Notably, GluA1 phosphorylation in the KO…

  1. Somatostatin Receptor 1 and 5 Double Knockout Mice Mimic Neurochemical Changes of Huntington's Disease Transgenic Mice

    PubMed Central

    Rajput, Padmesh S.; Kharmate, Geetanjali; Norman, Michael; Liu, Shi-He; Sastry, Bhagavatula R.; Brunicardi, Charles F.; Kumar, Ujendra

    2011-01-01

    Background Selective degeneration of medium spiny neurons and preservation of medium sized aspiny interneurons in striatum has been implicated in excitotoxicity and pathophysiology of Huntington's disease (HD). However, the molecular mechanism for the selective sparing of medium sized aspiny neurons and vulnerability of projection neurons is still elusive. The pathological characteristic of HD is an extensive reduction of the striatal mass, affecting caudate putamen. Somatostatin (SST) positive neurons are selectively spared in HD and Quinolinic acid/N-methyl-D-aspartic acid induced excitotoxicity, mimic the model of HD. SST plays neuroprotective role in excitotoxicity and the biological effects of SST are mediated by five somatostatin receptor subtypes (SSTR1-5). Methods and Findings To delineate subtype selective biological responses we have here investigated changes in SSTR1 and 5 double knockout mice brain and compared with HD transgenic mouse model (R6/2). Our study revealed significant loss of dopamine and cAMP regulated phosphoprotein of 32 kDa (DARPP-32) and comparable changes in SST, N-methyl-D-aspartic acid receptors subtypes, calbindin and brain nitric oxide synthase expression as well as in key signaling proteins including calpain, phospho-extracellular-signal-regulated kinases1/2, synapsin-IIa, protein kinase C-α and calcineurin in SSTR1/5−/− and R6/2 mice. Conversely, the expression of somatostatin receptor subtypes, enkephalin and phosphatidylinositol 3-kinases were strain specific. SSTR1/5 appears to be important in regulating NMDARs, DARPP-32 and signaling molecules in similar fashion as seen in HD transgenic mice. Conclusions This is the first comprehensive description of disease related changes upon ablation of G- protein coupled receptor gene. Our results indicate that SST and SSTRs might play an important role in regulation of neurodegeneration and targeting this pathway can provide a novel insight in understanding the pathophysiology of

  2. Kisspeptin regulation of arcuate neuron excitability in kisspeptin receptor knockout mice.

    PubMed

    Liu, Xinhuai; Herbison, Allan

    2015-05-01

    The G protein-coupled receptor 54 (GPR54) is critical for kisspeptin to activate GnRH neurons to modulate fertility. However, the often mismatching distribution of kisspeptin and GPR54 in the brain suggests that kisspeptin may also act on other receptors. The arcuate nucleus (ARN) is one brain region with a very high density of kisspeptin fibers but only limited evidence for the expression of GPR54. Using acute brain slice electrophysiology in combination with Gpr54 knockout (GPR54KO) mouse models, we examined whether actions of kisspeptin in the ARN were dependent upon GPR54. Cell-attached recordings from unidentified ARN neurons in wild-type mice revealed that approximately one third of neurons were either excited or inhibited by kisspeptin in a dose-dependent manner. The responses of ARN neurons to kisspeptin were exactly the same in GPR54KO mice despite effects of kisspeptin on GnRH neurons being abolished. To evaluate whether kisspeptin may be acting through neuropeptide FF receptors, the effects of an agonist RFamide-related peptide 3 (RFRP-3) and antagonists RF9 and BIBP-3226 were evaluated. Both the excitatory and inhibitory effects of kisspeptin were mimicked by the agonist RFRP-3. RF9 itself activated ARN neurons and suppressed only the inhibitory actions of kisspeptin. BIBP-3226 suppressed kisspeptin actions in 50% of neurons. Whole-cell recordings in GPR54KO mice demonstrated that both kisspeptin and RFRP-3 acted directly on the same ARN neurons and activated the same ion channels. Together, these studies demonstrate that kisspeptin can act partly through neuropeptide FF receptors to modulate neuronal activity independent of GPR54 in the mouse brain.

  3. Hypersomnolence and reduced activity in pan-leptin receptor knockout mice.

    PubMed

    Wang, Yuping; He, Junyun; Kastin, Abba J; Hsuchou, Hung; Pan, Weihong

    2013-11-01

    Excessive obesity correlates with hypersomnolence and impaired cognitive function, presumably induced by metabolic factors and cytokines. Production of the adipokine leptin correlates with the amount of adiposity, and leptin has been shown to promote sleep. To determine whether leptin plays a major role in the hypersomnolence of obesity, we measured sleep architecture in pan-leptin receptor knockout (POKO) mice that do not respond to leptin because of the production of a mutant, non-signaling receptor. The obese POKO mice had more non-rapid eye movement (NREM) sleep and less waking time than their littermate controls. This was mainly seen during the light span, although increased bouts of rapid eye movement sleep were also seen in the dark span. The increase of NREM sleep correlated with the extent of obesity. The POKO mice also had decreased locomotor activity and more immobility in the open field test, but there was no increase of forced immobility nor reduction of sucrose intake as would be seen in depression. The increased NREM sleep and reduced locomotor activity in the POKO mice suggest that it was obesity, rather than leptin signaling, that played a predominant role in altering sleep architecture and activity.

  4. Hypersomnolence and reduced activity in pan-leptin receptor knockout mice

    PubMed Central

    Wang, Yuping; He, Junyun; Kastin, Abba J.; Hsuchou, Hung; Pan, Weihong

    2013-01-01

    Excessive obesity correlates with hypersomnolence and impaired cognitive function, presumably induced by metabolic factors and cytokines. Production of the adipokine leptin correlates with the amount of adiposity, and leptin has been shown to promote sleep. To determine whether leptin plays a major role in the hypersomnolence of obesity, we measured sleep architecture in pan-leptin receptor knockout (POKO) mice that do not respond to leptin because of the production of a mutant, non-signaling receptor. The obese POKO mice had more non-rapid eye movement (NREM) sleep and less waking time than their littermate controls. This was mainly seen during the light span, although increased bouts of rapid eye movement (REM) sleep were also seen in the dark span. The increase of NREM sleep correlated with the extent of obesity. The POKO mice also had decreased locomotor activity and more immobility in the open field test, but there was no increase of forced immobility nor reduction of sucrose intake as would be seen in depression. The increased NREM sleep and reduced locomotor activity in the POKO mice suggest that it was obesity, rather than leptin signaling, that played a predominant role in altering sleep architecture and activity. PMID:23955775

  5. Acceleration of atherogenesis by COX-1-dependent prostanoid formation in low density lipoprotein receptor knockout mice.

    PubMed

    Praticò, D; Tillmann, C; Zhang, Z B; Li, H; FitzGerald, G A

    2001-03-13

    The cyclooxygenase (COX) product, prostacyclin (PGI(2)), inhibits platelet activation and vascular smooth-muscle cell migration and proliferation. Biochemically selective inhibition of COX-2 reduces PGI(2) biosynthesis substantially in humans. Because deletion of the PGI(2) receptor accelerates atherogenesis in the fat-fed low density lipoprotein receptor knockout mouse, we wished to determine whether selective inhibition of COX-2 would accelerate atherogenesis in this model. To address this hypothesis, we used dosing with nimesulide, which inhibited COX-2 ex vivo, depressed urinary 2,3 dinor 6-keto PGF(1alpha) by approximately 60% but had no effect on thromboxane formation by platelets, which only express COX-1. By contrast, the isoform nonspecific inhibitor, indomethacin, suppressed platelet function and thromboxane formation ex vivo and in vivo, coincident with effects on PGI(2) biosynthesis indistinguishable from nimesulide. Indomethacin reduced the extent of atherosclerosis by 55 +/- 4%, whereas nimesulide failed to increase the rate of atherogenesis. Despite their divergent effects on atherogenesis, both drugs depressed two indices of systemic inflammation, soluble intracellular adhesion molecule-1, and monocyte chemoattractant protein-1 to a similar but incomplete degree. Neither drug altered serum lipids and the marked increase in vascular expression of COX-2 during atherogenesis. Accelerated progression of atherosclerosis is unlikely during chronic intake of specific COX-2 inhibitors. Furthermore, evidence that COX-1-derived prostanoids contribute to atherogenesis suggests that controlled evaluation of the effects of nonsteroidal anti-inflammatory drugs and/or aspirin on plaque progression in humans is timely.

  6. Theca-specific estrogen receptor-alpha knockout mice lose fertility prematurely.

    PubMed

    Lee, Sungeun; Kang, Dong-Wook; Hudgins-Spivey, Susan; Krust, Andree; Lee, Eun-Young; Koo, Youngbum; Cheon, Yongpil; Gye, Myung Chan; Chambon, Pierre; Ko, ChemYong

    2009-08-01

    Estrogen receptor-alpha (Esr1) mediates estrogen action in regulating at all levels of the hypothalamic-pituitary-ovarian axis. Whereas the importance of Esr1 in hypothalamus and pituitary has been demonstrated by loss of fertility in the neuron- and pituitary-specific Esr1 knockout mice, whether Esr1 plays a critical role in the ovary remains to be determined. In the ovary, Esr1 is mainly expressed in the theca/interstitial cells and germinal epithelium and thus is believed to mediate estrogen action in these cells. In this study, we assessed the importance of Esr1 in the ovarian theca cells in regulating female reproduction. The Cre-LoxP approach was used to selectively delete the Esr1 gene in the theca cells, and the reproductive consequence of the deletion was measured. Adolescent theca-specific Esr1 knockout (thEsr1KO) mice (<4 months of age) are fertile and cycling. However, they begin to display an erratic pattern of estrous cycles and become infertile before they reach the age of 6 months. The ovaries of thEsr1KOmice (>or=4 months) have fewer corpora lutea but more antral follicles than the age-matching wild-type mice. The numbers of 17-hydroxylase-expressing cells are largely increased in the interstitium of the thEsr1KO mouse ovary. Interestingly, whereas basal levels of serum testosterone and FSH were mildly elevated, LH level was either markedly lower or undetectable in the thEsr1KO mice. When superstimulated by exogenous gonadotropins, thEsr1KO mice released significantly fewer oocytes that wild-type littermates and developed multiple hemorrhagic cysts. Taken together, this study demonstrates that theca Esr1 plays a critical role in regulating female reproduction.

  7. Dysregulation of Uterine Signaling Pathways in Progesterone Receptor-Cre Knockout of Dicer

    PubMed Central

    Andreu-Vieyra, Claudia V.; Kim, Tae Hoon; Jeong, Jae-Wook; Hodgson, Myles C.; Chen, Ruihong; Creighton, Chad J.; Lydon, John P.; Gunaratne, Preethi H.; DeMayo, Francesco J.; Matzuk, Martin M.

    2012-01-01

    Epithelial-stromal interactions in the uterus are required for normal uterine functions such as pregnancy, and multiple signaling pathways are essential for this process. Although Dicer and microRNA (miRNA) have been implicated in several reproductive processes, the specific roles of Dicer and miRNA in uterine development are not known. To address the roles of miRNA in the regulation of key uterine pathways, we generated a conditional knockout of Dicer in the postnatal uterine epithelium and stroma using progesterone receptor-Cre. These Dicer conditional knockout females are sterile with small uteri, which demonstrate significant defects, including absence of glandular epithelium and enhanced stromal apoptosis, beginning at approximately postnatal d 15, with coincident expression of Cre and deletion of Dicer. Specific miRNA (miR-181c, −200b, −101, let-7d) were down-regulated and corresponding predicted proapoptotic target genes (Bcl2l11, Aldh1a3) were up-regulated, reflecting the apoptotic phenomenon. Although these mice had normal serum hormone levels, critical uterine signaling pathways, including progesterone-responsive genes, Indian hedgehog signaling, and the Wnt/β-catenin canonical pathway, were dysregulated at the mRNA level. Importantly, uterine stromal cell proliferation in response to progesterone was absent, whereas uterine epithelial cell proliferation in response to estradiol was maintained in adult uteri. These data implicate Dicer and appropriate miRNA expression as essential players in the regulation of multiple uterine signaling pathways required for uterine development and appropriate function. PMID:22798293

  8. Delayed procedural learning in α7-nicotinic acetylcholine receptor knockout mice

    PubMed Central

    Young, J. W.; Meves, J. M.; Tarantino, I. S.; Caldwell, S.; Geyer, M. A.

    2014-01-01

    The α7-nicotinic acetylcholine receptor (nAChR) has long been a procognitive therapeutic target to treat schizophrenia. Evidence on the role of this receptor in cognition has been lacking, however, in part due to the limited availability of suitable ligands. The behavior of α7-nAChR knockout (KO) mice has been examined previously, but cognitive assessments using tests with cross-species translatability have been limited to date. Here, we assessed the cognitive performance of α7-nAChR KO and wild-type (WT) littermate mice in the attentional set-shifting task of executive functioning, the radial arm maze test of spatial working memory span capacity and the novel object recognition test of short-term memory. The reward motivation of these mutants was assessed using the progressive ratio breakpoint test. In addition, we assessed the exploratory behavior and sensorimotor gating using the behavioral pattern monitor and prepulse inhibition, respectively. α7-nAChR KO mice exhibited normal set-shifting, but impaired procedural learning (rule acquisition) in multiple paradigms. Spatial span capacity, short-term memory, motivation for food, exploration and sensorimotor gating were all comparable to WT littermates. The data presented here support the notion that this receptor is important for such procedural learning, when patterns in the environment become clear and a rule is learned. In combination with the impaired attention observed previously in these mice, this finding suggests that agonist treatments should be examined in clinical studies of attention and procedural learning, perhaps in combination with cognitive behavioral therapy. PMID:21679297

  9. The in vivo respiratory phenotype of the adenosine A1 receptor knockout mouse.

    PubMed

    Heitzmann, Dirk; Buehler, Philipp; Schweda, Frank; Georgieff, Michael; Warth, Richard; Thomas, Joerg

    2016-02-01

    The nucleoside adenosine has been implicated in the regulation of respiration, especially during hypoxia in the newborn. In this study the role of adenosine A1 receptors for the control of respiration was investigated in vivo. To this end, respiration of unrestrained adult and neonatal adenosine A1 receptor knockout mice (A1R(-/-)) was measured in a plethysmographic device. Under control conditions (21% O2) and mild hypoxia (12-15% O2) no difference of respiratory parameters was observed between adult wildtype (A1R(+/+)) and A1R(-/-) mice. Under more severe hypoxia (6-10% O2) A1R(+/+) mice showed, after a transient increase of respiration, a decrease of respiration frequency (fR) and tidal volume (VT) leading to a decrease of minute volume (MV). This depression of respiration during severe hypoxia was absent in A1R(-/-) mice which displayed a stimulated respiration as indicated by the enhancement of MV by some 50-60%. During hypercapnia-hyperoxia (3-10% CO2/97-90 % O2), no obvious differences in respiration of A1R(-/-) and A1R(+/+) was observed. In neonatal mice, the respiratory response to hypoxia was surprisingly similar in both genotypes. However, neonatal A1R(-/-) mice appeared to have more frequently periods of apnea during hypoxia and in the post-hypoxic control period. In conclusion, these data indicate that the adenosine A1 receptor is an important molecular component mediating hypoxic depression in adult mice and it appears to stabilize respiration of neonatal mice. PMID:26593641

  10. CXC receptor knockout mice: characterization of skeletal features and membranous bone healing in the adult mouse.

    PubMed

    Bischoff, David S; Sakamoto, Taylor; Ishida, Kenji; Makhijani, Nalini S; Gruber, Helen E; Yamaguchi, Dean T

    2011-02-01

    The potential role of CXC chemokines bearing the glu-leu-arg (ELR) motif in bone repair was studied using a cranial defect (CD) model in mice lacking the CXC receptor (mCXCR(-/-) knockout mice), which is homologous to knockout of the human CXC receptor 2 (CXCR2) gene. During the inflammatory stage of bone repair, ELR CXC chemokines are released by inflammatory cells and serve as chemotactic and angiogenic factors. mCXCR(-/-) mice were smaller in weight and length from base of tail to nose tip, compared to WT littermates. DEXA analysis indicated that bone mineral density (BMD), bone mineral content (BMC), total area (TA), bone area (BA), and total tissue mass (TTM) were decreased in the mCXCR(-/-) mice at 6, 12, and 18 weeks of age. Trabecular bone characteristics in mCXCR(-/-) (% bone, connectivity, number, and thickness) were reduced, and trabecular spacing was increased as evidenced by μCT. There was no difference in bone formation or resorption indices measured by bone histomorphometry. Trabecular BMD was not altered. Cortical bone volume, BMD, and thickness were reduced; whereas, bone marrow volume was increased in mCXCR(-/-). Decreased polar moment of inertia (J) in the tibias/femurs suggested that the mCXCR(-/-) long bones are weaker. This was confirmed by three-point bending testing of the femurs. CDs created in 6-week-old male mCXCR(-/-) and WT littermates were not completely healed at 12 weeks; WT animals, however, had significantly more bone in-growth than mCXCR(-/-). New bone sites were identified using polarized light and assessed for numbers of osteocyte (OCy) lacunae and blood vessels (BlV) around the original CD. In new bone, the number of BlV in WT was >2× that seen in mCXCR(-/-). Bone histomorphometry parameters in the cranial defect did not show any difference in bone formation or resorption markers. In summary, studies showed that mCXCR(-/-) mice have (1) reduced weight and size; (2) decreased BMD and BMC; (3) decreased amounts of trabecular

  11. Reduced anxiety-like and depression-related behavior in neuropeptide Y Y4 receptor knockout mice.

    PubMed

    Painsipp, E; Wultsch, T; Edelsbrunner, M E; Tasan, R O; Singewald, N; Herzog, H; Holzer, P

    2008-07-01

    Neuropeptide Y (NPY) acting through Y1 receptors reduces anxiety- and depression-like behavior in rodents, whereas Y2 receptor stimulation has the opposite effect. This study addressed the implication of Y4 receptors in emotional behavior by comparing female germ line Y4 knockout (Y4-/-) mice with control and germ line Y2-/- animals. Anxiety- and depression-like behavior was assessed with the open field (OF), elevated plus maze (EPM), stress-induced hyperthermia (SIH) and tail suspension tests (TST), respectively. Learning and memory were evaluated with the object recognition test (ORT). In the OF and EPM, both Y4-/- and Y2-/- mice exhibited reduced anxiety-related behavior and enhanced locomotor activity relative to control animals. Locomotor activity in a familiar environment was unchanged in Y4-/- but reduced in Y2-/- mice. The basal rectal temperature exhibited diurnal and genotype-related alterations. Control mice had temperature minima at noon and midnight, whereas Y4-/- and Y2-/- mice displayed only one temperature minimum at noon. The magnitude of SIH was related to time of the day and genotype in a complex manner. In the TST, the duration of immobility was significantly shorter in Y4-/- and Y2-/- mice than in controls. Object memory 6 h after initial exposure to the ORT was impaired in Y2-/- but not in Y4-/- mice, relative to control mice. These results show that genetic deletion of Y4 receptors, like that of Y2 receptors, reduces anxiety-like and depression-related behavior. Unlike Y2 receptor knockout, Y4 receptor knockout does not impair object memory. We propose that Y4 receptors play an important role in the regulation of behavioral homeostasis.

  12. Effects of dopamine D1-like and D2-like antagonists on cocaine discrimination in muscarinic receptor knockout mice.

    PubMed

    Thomsen, Morgane; Caine, Simon Barak

    2016-04-01

    Muscarinic and dopamine brain systems interact intimately, and muscarinic receptor ligands, like dopamine ligands, can modulate the reinforcing and discriminative stimulus (S(D)) effects of cocaine. To enlighten the dopamine/muscarinic interactions as they pertain to the S(D) effects of cocaine, we evaluated whether muscarinic M1, M2 or M4 receptors are necessary for dopamine D1 and/or D2 antagonist mediated modulation of the S(D) effects of cocaine. Knockout mice lacking M1, M2, or M4 receptors, as well as control wild-type mice and outbred Swiss-Webster mice, were trained to discriminate 10mg/kg cocaine from saline in a food-reinforced drug discrimination procedure. Effects of pretreatments with the dopamine D1 antagonist SCH 23390 and the dopamine D2 antagonist eticlopride were evaluated. In intact mice, both SCH 23390 and eticlopride attenuated the cocaine discriminative stimulus effect, as expected. SCH 23390 similarly attenuated the cocaine discriminative stimulus effect in M1 knockout mice, but not in mice lacking M2 or M4 receptors. The effects of eticlopride were comparable in each knockout strain. These findings demonstrate differences in the way that D1 and D2 antagonists modulate the S(D) effects of cocaine, D1 modulation being at least partially dependent upon activity at the inhibitory M2/M4 muscarinic subtypes, while D2 modulation appeared independent of these systems. PMID:26874213

  13. Induction of mammary gland development in estrogen receptor-alpha knockout mice.

    PubMed

    Bocchinfuso, W P; Lindzey, J K; Hewitt, S C; Clark, J A; Myers, P H; Cooper, R; Korach, K S

    2000-08-01

    Mammary glands from the estrogen receptor-a knockout (alphaERKO) mouse do not undergo ductal morphogenesis or alveolar development. Disrupted ERalpha signaling may result in reduced estrogen-responsive gene products in the mammary gland or reduced mammotropic hormones that contribute to the alphaERKO mammary phenotype. We report that circulating PRL is reduced in the female alphaERKO mouse. Implantation of an age-matched, heterozygous ERalpha pituitary isograft under the renal capsule of 25-day-old or 12-week-old alphaERKO mice increased circulating PRL and progesterone levels, and induced mammary gland development. Grafted alphaERKO mice also possessed hypertrophied corpora lutea demonstrating that PRL is luteotropic in the alphaERKO ovary. By contrast, ovariectomy at the time of pituitary grafting prevented mammary gland development in alphaERKO mice despite elevated PRL levels. Hormone replacement using pellet implants demonstrated that pharmacological doses of estradiol induced limited mammary ductal elongation, and estradiol in combination with progesterone stimulated lobuloalveolar development. PRL alone or in combination with progesterone or estradiol did not induce alphaERKO mammary growth. Estradiol and progesterone are required for the structural development of the alphaERKO mammary gland, and PRL contributes to this development by inducing ovarian progesterone levels. Therefore, the manifestation of the alphaERKO mammary phenotype appears due to the lack of direct estrogen action at the mammary gland and an indirect contributory role of estrogen signaling at the hypothalamic/pituitary axis.

  14. Attenuation of lithium-induced natriuresis and kaliuresis in P2Y2 receptor knockout mice

    PubMed Central

    Zhang, Yue; Li, Lijun; Kohan, Donald E.; Ecelbarger, Carolyn M.

    2013-01-01

    Whole body knockout (KO) of the P2Y2 receptor (P2Y2R) results in enhanced vasopressin V2 receptor activity and increased renal Na+ conservation. We hypothesized that P2Y2R KO mice would be less sensitive to lithium-induced natriuresis and kaliuresis due to attenuated downregulation of one or more of the major renal Na+ or K+ transporter/channel proteins. KO and wild-type (WT) mice were fed a control or lithium-added diet (40 mmol/kg food) for 14 days. Lithium-induced natriuresis and kaliuresis were significantly (∼25%) attenuated in KO mice. The subunits of the epithelial Na+ channel (ENaC) were variably affected by lithium and genotype, but, overall, medullary levels were decreased substantially by lithium (15–60%) in both genotypes. In contrast, cortical, β-, and γ-ENaC were increased by lithium (∼50%), but only in WT mice. Moreover, an assessment of ENaC activity by benzamil sensitivity suggested that lithium increased ENaC activity in WT mice but in not KO mice. In contrast, medullary levels of Na+-K+-2Cl− cotransporter 2 and cortical levels of the renal outer medullary K+ channel were not downregulated by lithium and were significantly (15–76%) higher in KO mice under both dietary conditions. In addition, under control conditions, tissue osmolality of the inner medulla as well as furosemide sensitivity were significantly higher in KO mice versus WT mice. Therefore, we suggest that increased expression of these proteins, particularly in the control state, reduces Na+ delivery to the distal nephron and provides a buffer to attenuate collecting duct-mediated natriuresis and kaliuresis. Additional studies are warranted to explore the potential therapeutic benefits of purinergic antagonism. PMID:23739592

  15. GABAB receptors and glucose homeostasis: evaluation in GABAB receptor knockout mice.

    PubMed

    Bonaventura, M M; Catalano, P N; Chamson-Reig, A; Arany, E; Hill, D; Bettler, B; Saravia, F; Libertun, C; Lux-Lantos, V A

    2008-01-01

    GABA has been proposed to inhibit insulin secretion through GABAB receptors (GABABRs) in pancreatic beta-cells. We investigated whether GABABRs participated in the regulation of glucose homeostasis in vivo. The animals used in this study were adult male and female BALB/C mice, mice deficient in the GABAB1 subunit of the GABABR (GABAB(-/-)), and wild types (WT). Blood glucose was measured under fasting/fed conditions and in glucose tolerance tests (GTTs) with a Lifescan Glucose meter, and serum insulin was measured by ELISA. Pancreatic insulin content and islet insulin were released by RIA. Western blots for the GABAB1 subunit in islet membranes and immunohistochemistry for insulin and GABAB1 were performed in both genotypes. BALB/C mice preinjected with Baclofen (GABABR agonist, 7.5 mg/kg ip) presented impaired GTTs and decreased insulin secretion compared with saline-preinjected controls. GABAB(-/-) mice showed fasting and fed glucose levels similar to WT. GABAB(-/-) mice showed improved GTTs at moderate glucose overloads (2 g/kg). Baclofen pretreatment did not modify GTTs in GABAB(-/-) mice, whereas it impaired normal glycemia reinstatement in WT. Baclofen inhibited glucose-stimulated insulin secretion in WT isolated islets but was without effect in GABAB(-/-) islets. In GABAB(-/-) males, pancreatic insulin content was increased, basal and glucose-stimulated insulin secretion were augmented, and impaired insulin tolerance test and increased homeostatic model assessment of insulin resistance index were determined. Immunohistochemistry for insulin demonstrated an increase of very large islets in GABAB(-/-) males. Results demonstrate that GABABRs are involved in the regulation of glucose homeostasis in vivo and that the constitutive absence of GABABRs induces alterations in pancreatic histology, physiology, and insulin resistance. PMID:17971510

  16. Regulation of FSHbeta and GnRH receptor gene expression in activin receptor II knockout male mice.

    PubMed

    Kumar, T Rajendra; Agno, Julio; Janovick, Jo Ann; Conn, P Michael; Matzuk, Martin M

    2003-12-30

    To examine in vivo, the local effects of inhibins and activins within the anterior pituitary, independent of their endocrine effects exerted from the gonad, in mediating FSH homeostasis, we used castrated knockout mice lacking either inhibin alpha or activin receptor II (ACVR2) alone or in combination. Compared to castrated wild-type (WT) mice, FSHbeta mRNA levels in the pituitaries of Acvr2 null mice were significantly downregulated in the absence of gonadal feedback. FSHbeta mRNA levels were not significantly higher in the pituitaries of castrated inhibin alpha null mice compared to those in Acvr2 null mice and remained the same in the pituitaries of castrated double mutant mice lacking both inhibin and ACVR2. In contrast to FSHbeta mRNA expression changes, pituitary FSH content was significantly reduced in Acvr2 null mice whereas it was only slightly upregulated in inhibin alpha null mice. Combined absence of both ACVR2 signaling and inhibins caused a decrease in FSH content compared to that in the absence of inhibins alone. These changes in pituitary content were in parallel to those in serum FSH levels in these three groups of castrated mice, suggesting that the unopposed actions of locally produced inhibins are dominant over those effects mediated by ACVR2 signaling to regulate FSH biosynthesis and secretion. Thus, our in vivo results demonstrate that within the pituitary, locally produced activins and inhibins exert their actions at distinct phases of FSH homeostasis. In an independent set of experiments, we tested whether in vivo signaling via ACVR2 is necessary for hypothalamic GnRH biosynthesis and for GnRH receptor expression. Our results demonstrate that in contrast to previous in vitro studies, signaling through ACVR2 is neither required for hypothalamic synthesis of GnRH peptide nor for expression of GnRH receptors in the anterior pituitary. We conclude that within the hypothalamic-pituitary short loop, ACVR2 signaling is critical only for FSH

  17. Impaired spatial learning and reduced adult hippocampal neurogenesis in histamine H1-receptor knockout mice.

    PubMed

    Ambrée, Oliver; Buschert, Jens; Zhang, Weiqi; Arolt, Volker; Dere, Ekrem; Zlomuzica, Armin

    2014-08-01

    The histamine H1-receptor (H1R) is expressed in wide parts of the brain including the hippocampus, which is involved in spatial learning and memory. Previous studies in H1R knockout (H1R-KO) mice revealed deficits in a variety of learning and memory tasks. It was also proposed that H1R activation is crucial for neuronal differentiation of neural progenitors. Therefore, the aim of this study was to investigate negatively reinforced spatial learning in the water-maze and to assess survival and neuronal differentiation of newborn cells in the adult hippocampus of H1R-KO mice. H1R-KO and wild-type (WT) mice were subjected to the following sequence of tests: (a) cued version, (b) place learning, (c) spatial probe, (d) long-term retention and (e) reversal learning. Furthermore hippocampal neurogenesis in terms of survival and differentiation was assessed in H1R-KO and WT mice. H1R-KO mice showed normal cued learning, but impaired place and reversal learning as well as impaired long-term retention performance. In addition, a marked reduction of newborn neurons in the hippocampus but no changes in differentiation of neural progenitors into neuronal and glial lineage was found in H1R-KO mice. Our data suggest that H1R deficiency in mice is associated with pronounced deficits in hippocampus-dependent spatial learning and memory. Furthermore, we herein provide first evidence that H1R deficiency in the mouse leads to a reduced neurogenesis. However, the exact mechanisms for the reduced number of cells in H1R-KO mice remain elusive and might be due to a reduced survival of newborn hippocampal neurons and/or a reduction in cell proliferation.

  18. A satellite cell-specific knockout of the androgen receptor reveals myostatin as a direct androgen target in skeletal muscle.

    PubMed

    Dubois, Vanessa; Laurent, Michaël R; Sinnesael, Mieke; Cielen, Nele; Helsen, Christine; Clinckemalie, Liesbeth; Spans, Lien; Gayan-Ramirez, Ghislaine; Deldicque, Louise; Hespel, Peter; Carmeliet, Geert; Vanderschueren, Dirk; Claessens, Frank

    2014-07-01

    Androgens have well-established anabolic actions on skeletal muscle, although the direct effects of the androgen receptor (AR) in muscle remain unclear. We generated satellite cell-specific AR-knockout (satARKO) mice in which the AR is selectively ablated in satellite cells, the muscle precursor cells. Total-limb maximal grip strength is decreased by 7% in satARKO mice, with soleus muscles containing ∼10% more type I fibers and 10% less type IIa fibers than the corresponding control littermates. The weight of the perineal levator ani muscle is markedly reduced (-52%). Thus, muscle AR is involved in fiber-type distribution and force production of the limb muscles, while it is a major determinant of the perineal muscle mass. Surprisingly, myostatin (Mstn), a strong inhibitor of skeletal muscle growth, is one of the most androgen-responsive genes (6-fold reduction in satARKO) through direct transcription activation by the AR. Consequently, muscle hypertrophy in response to androgens is augmented in Mstn-knockout mice. Our finding that androgens induce Mstn signaling to restrain their own anabolic actions has implications for the treatment of muscle wasting disorders.-Dubois, V., Laurent, M. R., Sinnesael, M., Cielen, N., Helsen, C., Clinckemalie, L., Spans, L., Gayan-Ramirez, G., Deldicque, L., Hespel, P., Carmeliet, G., Vanderschueren, D., and Claessens, F. A satellite cell-specific knockout of the androgen receptor reveals myostatin as a direct androgen target in skeletal muscle.

  19. Synaptic abnormalities and cytoplasmic glutamate receptor aggregates in contactin associated protein-like 2/Caspr2 knockout neurons

    PubMed Central

    Varea, Olga; Martin-de-Saavedra, Maria Dolores; Kopeikina, Katherine J.; Schürmann, Britta; Fleming, Hunter J.; Fawcett-Patel, Jessica M.; Bach, Anthony; Jang, Seil; Peles, Elior; Kim, Eunjoon; Penzes, Peter

    2015-01-01

    Central glutamatergic synapses and the molecular pathways that control them are emerging as common substrates in the pathogenesis of mental disorders. Genetic variation in the contactin associated protein-like 2 (CNTNAP2) gene, including copy number variations, exon deletions, truncations, single nucleotide variants, and polymorphisms have been associated with intellectual disability, epilepsy, schizophrenia, language disorders, and autism. CNTNAP2, encoded by Cntnap2, is required for dendritic spine development and its absence causes disease-related phenotypes in mice. However, the mechanisms whereby CNTNAP2 regulates glutamatergic synapses are not known, and cellular phenotypes have not been investigated in Cntnap2 knockout neurons. Here we show that CNTNAP2 is present in dendritic spines, as well as axons and soma. Structured illumination superresolution microscopy reveals closer proximity to excitatory, rather than inhibitory synaptic markers. CNTNAP2 does not promote the formation of synapses and cultured neurons from Cntnap2 knockout mice do not show early defects in axon and dendrite outgrowth, suggesting that CNTNAP2 is not required at this stage. However, mature neurons from knockout mice show reduced spine density and levels of GluA1 subunits of AMPA receptors in spines. Unexpectedly, knockout neurons show large cytoplasmic aggregates of GluA1. Here we characterize, for the first time to our knowledge, synaptic phenotypes in Cntnap2 knockout neurons and reveal a novel role for CNTNAP2 in GluA1 trafficking. Taken together, our findings provide insight into the biological roles of CNTNAP2 and into the pathogenesis of CNTNAP2-associated neuropsychiatric disorders. PMID:25918374

  20. Stress-induced dura vascular permeability does not develop in mast cell-deficient and neurokinin-1 receptor knockout mice.

    PubMed

    Kandere-Grzybowska, Kristiana; Gheorghe, Daniela; Priller, Josef; Esposito, Pamela; Huang, Man; Gerard, Norma; Theoharides, Theoharis C

    2003-08-01

    Migraine headaches are often precipitated by stress and seem to involve neurogenic inflammation (NI) of the dura mater associated with the sensation of throbbing pain. Trigeminal nerve stimulation had been reported to activate rat dura mast cells and increase vascular permeability, effects inhibited by neonatal pretreatment with capsaicin implicating sensory neuropeptides, such as substance P (SP). The aim of the present study was to investigate NI, assessed by extravasation of 99-Technetium-gluceptate (99Tc-G), as well as the role of mast cells, SP and its receptor (NK-1R) in dura mater of mice in response to acute stress. Restraint stress for thirty min significantly increased 99Tc-G extravasation in the dura mater of C57BL mice. This effect was absent in W/W(v) mast cell-deficient mice and NK-1 receptor knockout mice (NK-1R-/-), but was unaltered in SP knockout mice (SP-/-). Acute restraint stress also resulted in increased dura mast cell activation in C57BL mice, but not in NK-1R-/- mice. These data demonstrate for the first time that acute stress triggers NI and mast cell activation in mouse dura mater through the activation of NK-1 receptors. The fact that SP-/- mice had intact vascular permeability response to stress indicates that some other NK-1 receptor agonist may substitute for SP. These results may help explain initial events in pathogenesis of stress-induced migraines.

  1. Increased gabaergic input to ventral tegmental area dopaminergic neurons associated with decreased cocaine reinforcement in mu-opioid receptor knockout mice.

    PubMed

    Mathon, D S; Lesscher, H M B; Gerrits, M A F M; Kamal, A; Pintar, J E; Schuller, A G P; Spruijt, B M; Burbach, J P H; Smidt, M P; van Ree, J M; Ramakers, G M J

    2005-01-01

    There is general agreement that dopaminergic neurons projecting from the ventral tegmental area (VTA) to the nucleus accumbens and prefrontal cortex play a key role in drug reinforcement. The activity of these neurons is strongly modulated by the inhibitory and excitatory input they receive. Activation of mu-opioid receptors, located on GABAergic neurons in the VTA, causes hyperpolarization of these GABAergic neurons, thereby causing a disinhibition of VTA dopaminergic neurons. This effect of mu-opioid receptors upon GABA neurotransmission is a likely mechanism for mu-opioid receptor modulation of drug reinforcement. We studied mu-opioid receptor signaling in relation to cocaine reinforcement in wild-type and mu-opioid receptor knockout mice using a cocaine self-administration paradigm and in vitro electrophysiology. Cocaine self-administration was reduced in mu-opioid receptor knockout mice, suggesting a critical role of mu-opioid receptors in cocaine reinforcement. The frequency of spontaneous inhibitory post-synaptic currents onto dopaminergic neurons in the ventral tegmental area was increased in mu-opioid receptor knockout mice compared with wild-type controls, while the frequency of spontaneous excitatory post-synaptic currents was unaltered. The reduced cocaine self-administration and increased GABAergic input to VTA dopaminergic neurons in mu-opioid receptor knockout mice supports the notion that suppression of GABAergic input onto dopaminergic neurons in the VTA contributes to mu-opioid receptor modulation of cocaine reinforcement. PMID:15664692

  2. Enhanced response to mouse thyroid-stimulating hormone (TSH) receptor immunization in TSH receptor-knockout mice.

    PubMed

    Nakahara, Mami; Mitsutake, Norisato; Sakamoto, Hikaru; Chen, Chun-Rong; Rapoport, Basil; McLachlan, Sandra M; Nagayama, Yuji

    2010-08-01

    Graves-like hyperthyroidism is induced in BALB/c mice by immunization with adenovirus expressing the human TSH receptor (TSHR) A-subunit (amino acids 1-289). However, because of nonidentity between the human and mouse TSHR ( approximately 87% amino acid homology), we compared the responses of mice immunized with adenoviruses expressing either the mouse or the human TSHR A-subunit. Wild-type (wt) BALB/c mice immunized with the mouse A-subunit developed neither TSHR antibodies (measured by flow cytometry) nor thyroid lymphocytic infiltration. However, wt C57BL/6 mice developed sparse intrathyroidal lymphocyte infiltration without antibody production. Depletion of naturally occurring regulatory CD4(+)CD25(+) T cells had little effect. These results indicate the inability to break tolerance to the mouse TSHR in wt mice. In contrast, TSHR knockout (KO) BALB/c mice generated mouse TSHR antibodies in response to mouse A-subunit immunization and augmented human TSHR antibody response to human A-subunit immunization. Thyroid-stimulating antibody titers measured in a functional bioassay were comparable in human A-subunit immunized wt mice and in TSHR KO mice immunized with either the mouse or human A-subunit. In conclusion, immune response to the mouse TSHR is readily induced in TSHR KO but not in wt mice. Only in the former does immunization with adenovirus expressing the mouse A-subunit generate antibodies capable of activating the mouse TSHR. TSHR KO mice are, therefore, of value for future studies dissecting the autoimmune response to the mouse TSHR.

  3. Interactions of (+)- and (-)-8- and 7-hydroxy-2-(di-n-propylamino)tetralin at human (h)D3, hD2 and h serotonin1A receptors and their modulation of the activity of serotoninergic and dopaminergic neurones in rats.

    PubMed

    Lejeune, F; Newman-Tancredi, A; Audinot, V; Millan, M J

    1997-03-01

    The aminotetralins, 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) and 7-OH-DPAT behave as preferential agonists at serotonin (5-HT)1A and dopamine D3 and D2 receptors, respectively. In our study, we evaluated the influence of their (+)- and (-) isomers on the electrical activity of serotoninergic neurones of the dorsal raphe nucleus (DRN), which bear 5-HT1A autoreceptors, and of dopaminergic neurones of the ventral tegmental area (VTA), which possess inhibitory D3 and D2 receptors. These actions were compared to their in vitro interactions with cloned, human (h)5-HT1A, hD3 and hD2 receptors. In binding studies, racemic 8-OH-DPAT showed 100-fold selectivity for h5-HT1A vs. hD2 and hD3 receptors and there was little difference between its (+)- and (-)-isomers either in terms of their potency at 5-HT1A receptors or of their selectivity at 5-HT1A vs hD2/hD3 sites. Nevertheless, the (+)-isomer was markedly more efficacious than its (-)-counterpart in stimulating the binding of guanosine 5'-O-(3-[35S]thiotriphosphate) ([35S]-GTPgammaS) at h5-HT1A receptors, a measure of coupling to G-proteins; 90 vs. 57% maximal stimulation respectively, relative to 5-HT = 100%. Also the (+)-isomer was ca. 3-fold more potent than the (-)-isomer in inhibiting the firing rate of DRN neurones. These actions were abolished by the 5-HT1A antagonist, (-)-tertatolol, but unaffected by the hD2/hD3 antagonist, haloperidol. Whereas (+)-8-OH-DPAT stimulated VTA neurone firing with a bell-shaped dose response curve, the (-)-isomer only inhibited VTA firing. The (+)-isomer-induced stimulation was blocked by (-)-tertatolol but not haloperidol, whereas the (-)-isomer-induced inhibition was abolished by haloperidol and unaffected by (-)-tertatolol. In contrast to 8-OH-DPAT, the (+)- and (-)isomers of 7-OH-DPAT showed marked stereoselectivity inasmuch as the latter bound with 20-fold less potency than the former at hD3 and, at higher concentrations, hD2 receptors. Correspondingly, (+)-7-OH-DPAT was

  4. Drebrin depletion alters neurotransmitter receptor levels in protein complexes, dendritic spine morphogenesis and memory-related synaptic plasticity in the mouse hippocampus.

    PubMed

    Jung, Gangsoo; Kim, Eun-Jung; Cicvaric, Ana; Sase, Sunetra; Gröger, Marion; Höger, Harald; Sialana, Fernando Jayson; Berger, Johannes; Monje, Francisco J; Lubec, Gert

    2015-07-01

    Drebrin an actin-bundling key regulator of dendritic spine genesis and morphology, has been recently proposed as a regulator of hippocampal glutamatergic activity which is critical for memory formation and maintenance. Here, we examined the effects of genetic deletion of drebrin on dendritic spine and on the level of complexes containing major brain receptors. To this end, homozygous and heterozygous drebrin knockout mice generated in our laboratory and related wild-type control animals were studied. Level of protein complexes containing dopamine receptor D1/dopamine receptor D2, 5-hydroxytryptamine receptor 1A (5-HT1(A)R), and 5-hydroxytryptamine receptor 7 (5-HT7R) were significantly reduced in hippocampus of drebrin knockout mice whereas no significant changes were detected for GluR1, 2, and 3 and NR1 as examined by native gel-based immunoblotting. Drebrin depletion also altered dendritic spine formation, morphology, and reduced levels of dopamine receptor D1 in dendritic spines as evaluated using immunohistochemistry/confocal microscopy. Electrophysiological studies further showed significant reduction in memory-related hippocampal synaptic plasticity upon drebrin depletion. These findings provide unprecedented experimental support for a role of drebrin in the regulation of memory-related synaptic plasticity and neurotransmitter receptor signaling, offer relevant information regarding the interpretation of previous studies and help in the design of future studies on dendritic spines.

  5. [Effect of P2X7 receptor knock-out on bone cancer pain in mice].

    PubMed

    Zhao, Xin; Liu, Hui-Zhu; Zhang, Yu-Qiu

    2016-06-25

    Cancer pain is one of the most common symptoms in patients with late stage cancer. Lung, breast and prostate carcinoma are the most common causes of pain from osseous metastasis. P2X7 receptor (P2X7R) is one of the subtypes of ATP-gated purinergic ion channel family, predominately distributed in microglia in the spinal cord. Activation of P2X7Rs in the spinal dorsal horn has been associated with release of proinflammatory cytokines from glial cells, causing increased neuronal excitability and exaggerated nociception. Mounting evidence implies a critical role of P2X7R in inflammatory and neuropathic pain. However, whether P2X7R is involved in cancer pain remains controversial. Here we established a bone cancer pain model by injecting the Lewis lung carcinoma cells into the femur bone marrow cavity of C57BL/6J wild-type mice (C57 WT mice) and P2X7R knockout mice (P2rx7(-/-) mice) to explore the role of P2X7R in bone cancer pain. Following intrafemur carcinoma inoculation, robust mechanical allodynia and thermal hyperalgesia in C57 WT mice were developed on day 7 and 14, respectively, and persisted for at least 28 days in the ipsilateral hindpaw of the affected limb. CatWalk gait analysis showed significant decreases in the print area and stand phase, and a significant increase in swing phase in the ipsilateral hindpaw on day 21 and 28 after carcinoma cells inoculation. Histopathological sections (hematoxylin and eosin stain) showed that the bone marrow of the affected femur was largely replaced by invading tumor cells, and the femur displayed medullary bone loss and bone destruction on day 28 after inoculation. Unexpectedly, no significant changes in bone cancer-induced hypersensitivity of pain behaviors were found in P2rx7(-/-) mice, and the changes of pain-related values in CatWalk gait analysis even occurred earlier in P2rx7(-/-) mice, as compared with C57 WT mice. Together with our previous study in rats that blockade of P2X7R significantly alleviated bone cancer

  6. HSL-knockout mouse testis exhibits class B scavenger receptor upregulation and disrupted lipid raft microdomains[S

    PubMed Central

    Casado, María Emilia; Huerta, Lydia; Ortiz, Ana Isabel; Pérez-Crespo, Mirian; Gutiérrez-Adán, Alfonso; Kraemer, Fredric B.; Lasunción, Miguel Ángel; Busto, Rebeca; Martín-Hidalgo, Antonia

    2012-01-01

    There is a tight relationship between fertility and changes in cholesterol metabolism during spermatogenesis. In the testis, class B scavenger receptors (SR-B) SR-BI, SR-BII, and LIMP II mediate the selective uptake of cholesterol esters from HDL, which are hydrolyzed to unesterified cholesterol by hormone-sensitive lipase (HSL). HSL is critical because HSL knockout (KO) male mice are sterile. The aim of the present work was to determine the effects of the lack of HSL in testis on the expression of SR-B, lipid raft composition, and related cell signaling pathways. HSL-KO mouse testis presented altered spermatogenesis associated with decreased sperm counts, sperm motility, and infertility. In wild-type (WT) testis, HSL is expressed in elongated spermatids; SR-BI, in Leydig cells and spermatids; SR-BII, in spermatocytes and spermatids but not in Leydig cells; and LIMP II, in Sertoli and Leydig cells. HSL knockout male mice have increased expression of class B scavenger receptors, disrupted caveolin-1 localization in lipid raft plasma membrane microdomains, and activated phospho-ERK, phospho-AKT, and phospho-SRC in the testis, suggesting that class B scavenger receptors are involved in cholesterol ester uptake for steroidogenesis and spermatogenesis in the testis. PMID:22988039

  7. Paired immunoglobulin-like receptor B knockout does not enhance axonal regeneration or locomotor recovery after spinal cord injury.

    PubMed

    Nakamura, Yuka; Fujita, Yuki; Ueno, Masaki; Takai, Toshiyuki; Yamashita, Toshihide

    2011-01-21

    Myelin components that inhibit axonal regeneration are believed to contribute significantly to the lack of axonal regeneration noted in the adult central nervous system. Three proteins found in myelin, Nogo, myelin-associated glycoprotein, and oligodendrocyte-myelin glycoprotein, inhibit neurite outgrowth in vitro. All of these proteins interact with the same receptors, namely, the Nogo receptor (NgR) and paired immunoglobulin-like receptor B (PIR-B). As per previous reports, corticospinal tract (CST) regeneration is not enhanced in NgR-knock-out mice after spinal cord injury. Therefore, we assessed CST regeneration in PIR-B-knock-out mice. We found that hindlimb motor function, as assessed using the Basso mouse scale, footprint test, inclined plane test, and beam walking test, did not differ between the PIR-B-knock-out and wild-type mice after dorsal hemisection of the spinal cord. Further, tracing of the CST fibers after injury did not reveal enhanced axonal regeneration or sprouting in the CST of the PIR-B-knock-out mice. Systemic administration of NEP1-40, a NgR antagonist, to PIR-B knock-out mice did not enhance the regenerative response. These results indicate that PIR-B knock-out is not sufficient to induce extensive axonal regeneration after spinal cord injury. PMID:21087927

  8. Data on Arc and Zif268 expression in the brain of the α-2A adrenergic receptor knockout mouse.

    PubMed

    Sanders, Jeff

    2016-06-01

    The α2-adrenergic receptor (α2-AR) is widely distributed in the brain with distinct roles for α2-AR subtypes (A, B and C). In this article, data are provided on Activity Regulated Cytoskeleton Associated Protein (Arc) and Zif268 expression in the brain of the α2A-AR knockout (α2A-AR KO) mouse. These data are supplemental to an original research article examining Arc and Zif268 expression in rats injected with the α2-AR antagonist, RX821002 (http://dx.doi.org/10.1016/j.neulet.2015.12.002. [1]). PMID:26952134

  9. Characterization of the retina in the alpha7 nicotinic acetylcholine receptor knockout mouse

    NASA Astrophysics Data System (ADS)

    Smith, Marci L.

    Acetylcholine receptors (AChRs) are involved in visual processing and are expressed by inner retinal neurons in all species studied to date (Keyser et al., 2000; Dmitrieva et al., 2007; Liu et al., 2009), but their distribution in the mouse retina remains unknown. Reductions in alpha7 nicotinic AChRs (nAChRs) are thought to contribute to memory and visual deficits observed in Alzheimer's and schizophrenia (Coyle et al., 1983; Nordberg et al., 1999; Leonard et al., 2006). However, the alpha7 nAChR knockout (KO) mouse has a mild phenotype (Paylor et al., 1998; Fernandes et al., 2006; Young et al., 2007; Origlia et al., 2012). The purpose of this study was to determine the expression of AChRs in wildtype (WT) mouse retina and to assess whether up-regulation of other AChRs in the alpha7 nAChR KO retina may explain the minimal deficits described in the KO mouse. Reverse-transcriptase PCR (RT-PCR) showed that mRNA transcripts for alpha2-7, alpha 9, alpha10, beta2-4 nAChR subunits and m1-m5 muscarinic AChR (mAChR) subtypes were present in WT murine retina. Western blot analysis confirmed the presence of alpha3-5, alpha9, and m1-m5 AChR proteins and immunohistochemical analysis demonstrated nAChR and mAChR proteins expressed by subsets of bipolar, amacrine and ganglion cells. This is the first reported expression of alpha9 and alpha10 nAChR transcripts and alpha9 nAChR proteins in the retina of any species. Quantitative RT-PCR (qPCR) showed changes in AChR transcript expression in the alpha7 nAChR KO mouse retina relative to WT. Within whole retina alpha2, alpha9, alpha10, beta4, m1 and m4 AChR transcripts were up-regulated, while alpha5 nAChR transcripts were down-regulated. However, cell populations showed subtle differences; m4 mAChR transcripts were up-regulated in the ganglion cell layer and outer portion of the inner nuclear layer (oINL),while beta4 nAChR transcript up-regulation was limited to the oINL. Surprisingly, alpha2, alpha9, beta4, m2 and m4 transcripts were

  10. Oxytocin and estrogen receptor alpha and beta knockout mice provide discriminably different odor cues in behavioral assays.

    PubMed

    Kavaliers, M; Agmo, A; Choleris, E; Gustafsson, J A; Korach, K S; Muglia, L J; Pfaff, D W; Ogawa, S

    2004-08-01

    Social behavior involves both the recognition and pro-duction of social cues. Mice with selective deletion(knockout) of either the gene for oxytocin (OT) or genes for the estrogen receptor (ER) -c or -B display impaired social recognition. In this study we demonstrate that these gene knockout mice also provide discriminably different social stimuli in behavioral assays. In an odor choice test, which is a measure of social interest and discrimination, outbred female Swiss-Webster mice discriminated the urine odors of male knock-outs IKO: OTKO, alphaERKO, betaERKO) from the odors of their wildtype littermates (WT: OTWT, alphaERWT, betaERWT). Females showed marked initial choices of the urine odors of OTWT and betaERWT males over those of OTKOand PERKO males, and alphaERKO males over alphaERWT males. The odors of OTKO and betaERKO males also induced aversive, analgesic responses, with the odors of WTs having no significant effects. Odors of both the alphaERWT andalphaERKO males induced aversive, analgesic responses,with the odors of the WT inducing significantly greater analgesia. The odors of restraint stressed WT and KO males also elicited analgesia with, again, females dis-playing significantly greater responses to the odors of stressed OTKO and betaERKO males than their WTs, and significantly lower analgesia to the odors of stressedalphaERKO than alphaERWT males. These findings show that the KO mice are discriminated from their WTs on the basis of odor and that the various KOs differ in the relative attractiveness/aversiveness of their odors. Therefore, in behavioral assays one causal route by which gene inactivation alters the social behavior of knockout mice may be mediated through the partners'modified responses to their odors.

  11. Cannabinoid 1 receptor knockout mice display cold allodynia, but enhanced recovery from spared-nerve injury-induced mechanical hypersensitivity

    PubMed Central

    Piskoun, Boris; Russo, Lori; Norcini, Monica; Blanck, Thomas; Recio-Pinto, Esperanza

    2016-01-01

    Background The function of the Cannabinoid 1 receptor (CB1R) in the development of neuropathic pain is not clear. Mounting evidence suggest that CB1R expression and activation may contribute to pain. Cannabinoid 1 receptor knockout mice (CB1R−/−) generated on a C57Bl/6 background exhibit hypoalgesia in the hotplate assay and formalin test. These findings suggest that Cannabinoid 1 receptor expression mediates the responses to at least some types of painful stimuli. By using this mouse line, we sought to determine if the lack of Cannabinoid 1 receptor unveils a general hypoalgesic phenotype, including protection against the development of neuropathic pain. The acetone test was used to measure cold sensitivity, the electronic von Frey was used to measure mechanical thresholds before and after spared-nerve injury, and analysis of footprint patterns was conducted to determine if motor function is differentially affected after nerve-injury in mice with varying levels of Cannabinoid 1 receptor. Results At baseline, CB1R−/− mice were hypersensitive in the acetone test, and this phenotype was maintained after spared-nerve injury. Using calcium imaging of lumbar dorsal root ganglion (DRG) cultures, a higher percentage of neurons isolated from CB1R−/− mice were menthol sensitive relative to DRG isolated from wild-type (CB1R+/+) mice. Baseline mechanical thresholds did not differ among genotypes, and mechanical hypersensitivity developed similarly in the first two weeks following spared-nerve injury (SNI). At two weeks post-SNI, CB1R−/− mice recovered significantly from mechanical hypersensitivity, while the CB1R+/+ mice did not. Heterozygous knockouts (CB1R+/−) transiently developed cold allodynia only after injury, but recovered mechanical thresholds to a similar extent as the CB1R−/− mice. Sciatic functional indices, which reflect overall nerve health, and alternation coefficients, which indicate uniformity of strides, were not significantly different

  12. Higher density of serotonin-1A receptors in the hippocampus and cerebral cortex of alcohol-preferring P rats

    SciTech Connect

    Wong, D.T.; Threlkeld, P.G. ); Lumeng, L.; Li, Ting-Kai )

    1990-01-01

    Saturable ({sup 3}H)-80HDPAT binding to 5HT-1A receptors in membranes prepared from hippocampus and frontal cerebral cortex of alcohol-preferring (P) rats and of alcohol-nonpreferring (NP) rats has been compared. The B{sub max} values or densities of recognition sites for 5HT-1A receptors in both brain areas of the P rats are 38 and 44 percent lower in the P rats than in the NP rats. The corresponding K{sub D} values are 38 and 44 percent lower in the P rats than in the NP rats, indicating higher affinities of the recognition sites for the 5HT-1A receptors in hippocampus and cerebral cortex of the P rats. These findings indicate either an enrichment of 5HT-1A receptor density during selective breeding for alcohol preference or an upregulation of 5HT-1A receptors of 5HT found in these brain areas of P rats as compared with the NP rats.

  13. Genetic background can result in a marked or minimal effect of gene knockout (GPR55 and CB2 receptor) in experimental autoimmune encephalomyelitis models of multiple sclerosis.

    PubMed

    Sisay, Sofia; Pryce, Gareth; Jackson, Samuel J; Tanner, Carolyn; Ross, Ruth A; Michael, Gregory J; Selwood, David L; Giovannoni, Gavin; Baker, David

    2013-01-01

    Endocannabinoids and some phytocannabinoids bind to CB1 and CB2 cannabinoid receptors, transient receptor potential vanilloid one (TRPV1) receptor and the orphan G protein receptor fifty-five (GPR55). Studies using C57BL/10 and C57BL/6 (Cnr2 (tm1Zim)) CB2 cannabinoid receptor knockout mice have demonstrated an immune-augmenting effect in experimental autoimmune encephalomyelitis (EAE) models of multiple sclerosis. However, other EAE studies in Biozzi ABH mice often failed to show any treatment effect of either CB2 receptor agonism or antagonism on inhibition of T cell autoimmunity. The influence of genetic background on the induction of EAE in endocannabinoid system-related gene knockout mice was examined. It was found that C57BL/6.GPR55 knockout mice developed less severe disease, notably in female mice, following active induction with myelin oligodendrocyte glycoprotein 35-55 peptide. In contrast C57BL/6.CB2 (Cnr2 (Dgen)) receptor knockout mice developed augmented severity of disease consistent with the genetically and pharmacologically-distinct, Cnr2 (tm1Zim) mice. However, when the knockout gene was bred into the ABH mouse background and EAE induced with spinal cord autoantigens the immune-enhancing effect of CB2 receptor deletion was lost. Likewise CB1 receptor and transient receptor potential vanilloid one knockout mice on the ABH background demonstrated no alteration in immune-susceptibility, in terms of disease incidence and severity of EAE, in contrast to that reported in some C57BL/6 mouse studies. Furthermore the immune-modulating influence of GPR55 was marginal on the ABH mouse background. Whilst sedative doses of tetrahydrocannabinol could induce immunosuppression, this was associated with a CB1 receptor rather than a CB2 receptor-mediated effect. These data support the fact that non-psychoactive doses of medicinal cannabis have a marginal influence on the immune response in MS. Importantly, it adds a note of caution for the translational value of some

  14. Genetic Background Can Result in a Marked or Minimal Effect of Gene Knockout (GPR55 and CB2 Receptor) in Experimental Autoimmune Encephalomyelitis Models of Multiple Sclerosis

    PubMed Central

    Jackson, Samuel J.; Tanner, Carolyn; Ross, Ruth A.; Michael, Gregory J.; Selwood, David L.; Giovannoni, Gavin; Baker, David

    2013-01-01

    Endocannabinoids and some phytocannabinoids bind to CB1 and CB2 cannabinoid receptors, transient receptor potential vanilloid one (TRPV1) receptor and the orphan G protein receptor fifty-five (GPR55). Studies using C57BL/10 and C57BL/6 (Cnr2tm1Zim) CB2 cannabinoid receptor knockout mice have demonstrated an immune-augmenting effect in experimental autoimmune encephalomyelitis (EAE) models of multiple sclerosis. However, other EAE studies in Biozzi ABH mice often failed to show any treatment effect of either CB2 receptor agonism or antagonism on inhibition of T cell autoimmunity. The influence of genetic background on the induction of EAE in endocannabinoid system-related gene knockout mice was examined. It was found that C57BL/6.GPR55 knockout mice developed less severe disease, notably in female mice, following active induction with myelin oligodendrocyte glycoprotein 35-55 peptide. In contrast C57BL/6.CB2 (Cnr2Dgen) receptor knockout mice developed augmented severity of disease consistent with the genetically and pharmacologically-distinct, Cnr2tm1Zim mice. However, when the knockout gene was bred into the ABH mouse background and EAE induced with spinal cord autoantigens the immune-enhancing effect of CB2 receptor deletion was lost. Likewise CB1 receptor and transient receptor potential vanilloid one knockout mice on the ABH background demonstrated no alteration in immune-susceptibility, in terms of disease incidence and severity of EAE, in contrast to that reported in some C57BL/6 mouse studies. Furthermore the immune-modulating influence of GPR55 was marginal on the ABH mouse background. Whilst sedative doses of tetrahydrocannabinol could induce immunosuppression, this was associated with a CB1 receptor rather than a CB2 receptor-mediated effect. These data support the fact that non-psychoactive doses of medicinal cannabis have a marginal influence on the immune response in MS. Importantly, it adds a note of caution for the translational value of some

  15. A muscle-specific knockout implicates nuclear receptor coactivator MED1 in the regulation of glucose and energy metabolism.

    PubMed

    Chen, Wei; Zhang, Xiaoting; Birsoy, Kivanc; Roeder, Robert G

    2010-06-01

    As conventional transcriptional factors that are activated in diverse signaling pathways, nuclear receptors play important roles in many physiological processes that include energy homeostasis. The MED1 subunit of the Mediator coactivator complex plays a broad role in nuclear receptor-mediated transcription by anchoring the Mediator complex to diverse promoter-bound nuclear receptors. Given the significant role of skeletal muscle, in part through the action of nuclear receptors, in glucose and fatty acid metabolism, we generated skeletal muscle-specific Med1 knockout mice. Importantly, these mice show enhanced insulin sensitivity and improved glucose tolerance as well as resistance to high-fat diet-induced obesity. Furthermore, the white muscle of these mice exhibits increased mitochondrial density and expression of genes specific to type I and type IIA fibers, indicating a fast-to-slow fiber switch, as well as markedly increased expression of the brown adipose tissue-specific UCP-1 and Cidea genes that are involved in respiratory uncoupling. These dramatic results implicate MED1 as a powerful suppressor in skeletal muscle of genetic programs implicated in energy expenditure and raise the significant possibility of therapeutical approaches for metabolic syndromes and muscle diseases through modulation of MED1-nuclear receptor interactions.

  16. Increased brain monoaminergic tone after the NMDA receptor GluN2A subunit gene knockout is responsible for resistance to the hypnotic effect of nitrous oxide.

    PubMed

    Petrenko, Andrey B; Yamakura, Tomohiro; Kohno, Tatsuro; Sakimura, Kenji; Baba, Hiroshi

    2013-01-01

    N-methyl-d-aspartate (NMDA) receptors can be inhibited by inhalational anesthetics in vitro at clinically relevant concentrations. Here, to clarify the role of NMDA receptors in anesthetic-induced unconsciousness, we examined the hypnotic properties of isoflurane, sevoflurane and nitrous oxide in NMDA receptor GluN2A subunit knockout mice. The hypnotic properties of inhalational anesthetics were evaluated in mice in the loss of righting reflex (LORR) assay by measuring the 50% concentration for LORR (LORR ED(50)). Knockout mice displayed isoflurane and sevoflurane LORR ED(50) values similar to wild-type controls, indicating no significant contribution of these receptors to the hypnotic action of halogenated anesthetics. However, compared with wild-type controls, mutant mice displayed larger isoflurane LORR ED(50) values in the presence of nitrous oxide, indicating a resistance to this gaseous anesthetic. Knockout mice have enhanced brain monoaminergic activity which occurs secondary to NMDA receptor dysfunction, and the observed resistance to the isoflurane LORR ED(50)-sparing effect of nitrous oxide could be abolished by pretreatment with the dopamine D(2) receptor antagonist droperidol or with the serotonin 5-HT(2A) receptor antagonist ketanserin. Thus, resistance to nitrous oxide in knockout mice appears to be a secondary phenomenon of monoaminergic origin and not a direct result of impaired NMDA receptor function. Our results indicate that NMDA receptors are not critically involved in the hypnotic action of conventionally-used inhalational anesthetics. Also, they suggest that increased brain monoaminergic tone can diminish the effects of general anesthesia. Finally, they provide further evidence that changes secondary to genetic manipulation can explain the results obtained in global knockouts. PMID:23123346

  17. Histamine responses of large neostriatal interneurons in histamine H1 and H2 receptor knock-out mice.

    PubMed

    Ogawa, Sachie; Yanai, Kazuhiko; Watanabe, Takeshi; Wang, Zhi-Ming; Akaike, Hironari; Ito, Yushi; Akaike, Norio

    2009-03-16

    Histamine (HA) is an important neuro-modulator, contributing to a variety of physiological responses in the mammalian central nervous system (CNS). However there is little information about the cell/signaling mechanism underlying its role. In the present study, we characterized HA responses in single large neostriatal neurons acutely dissociated from wild type (WT) and HA receptor knock-out (KO) mice, with a particular emphasis on identifying the role of HA receptor subtypes. HA (10 microM) and a selective H(2) receptor agonist dimaprit (1 microM) both evoked an inward current in H(1)-KO mice, and HA and a selective H(1) receptor agonist HTMT (10 microM) both evoked an inward current in H(2)-KO mice. In the H(1) and H(2) double (H(1/2)) KO mice, there was no response to either the application of HA or the selective H(1), H(2) receptor agonists. Hence we have confirmed that the targeted genes were indeed absent in these KO mice and that both receptor subtypes contribute to HA's excitatory actions. Furthermore the HA-induced inward currents were mediated by a decrease in current through K(+) channels. In addition, we observed the effects of methamphetamine (METH) on the locomotor activity of WT and HA receptor KO mice, and found that METH-induced behavioral sensitization is evident in H(1/2)-KO mice, but not in H(1)- or H(2)-KO mice. These observations suggest that suppressive roles of HA on methamphetamine-induced behavioral sensitization would be mediated through both H(1) and H(2) receptors in the CNS including neostriatum.

  18. IL-1 receptor-antagonist (IL-1Ra) knockout mice show anxiety-like behavior by aging.

    PubMed

    Wakabayashi, Chisato; Numakawa, Tadahiro; Odaka, Haruki; Ooshima, Yoshiko; Kiyama, Yuji; Manabe, Toshiya; Kunugi, Hiroshi; Iwakura, Yoichiro

    2015-07-10

    Interleukin 1 (IL-1) plays a critical role in stress responses, and its mRNA is induced in the brain by restraint stress. Previously, we reported that IL-1 receptor antagonist (IL-1Ra) knockout (KO) mice, which lacked IL-1Ra molecules that antagonize the IL-1 receptor, showed anti-depression-like behavior via adrenergic modulation at the age of 8 weeks. Here, we report that IL-1Ra KO mice display an anxiety-like phenotype that is induced spontaneously by aging in the elevated plus-maze (EPM) test. This anxiety-like phenotype was improved by the administration of diazepam. The expression of the anxiety-related molecule glucocorticoid receptor (GR) was significantly reduced in 20-week-old but not in 11-week-old IL-1Ra KO mice compared to wild-type (WT) littermates. The expression of the mineralocorticoid receptor (MR) was not altered between IL-1Ra KO mice and WT littermates at either 11 or 20 weeks old. Analysis of monoamine concentration in the hippocampus revealed that tryptophan, the serotonin metabolite 5-hydroxyindole acetic acid (5-HIAA), and the dopamine metabolite homovanillic acid (HVA) were significantly increased in 20-week-old IL-1Ra KO mice compared to littermate WT mice. These findings strongly suggest that the anxiety-like behavior observed in older mice was caused by the complicated alteration of monoamine metabolism and/or GR expression in the hippocampus.

  19. Phenotypic screening of hepatocyte nuclear factor (HNF) 4-{gamma} receptor knockout mice

    SciTech Connect

    Gerdin, Anna Karin; Surve, Vikas V.; Joensson, Marie; Bjursell, Mikael; Edenro, Anne; Schuelke, Meint; Saad, Alaa; Bjurstroem, Sivert; Lundgren, Elisabeth Jensen; Snaith, Michael; Fransson-Steen, Ronny; Toernell, Jan; Bohlooly-Y, Mohammad . E-mail: mohammad.bohlooly@astrazeneca.com

    2006-10-20

    Using the mouse as a model organism in pharmaceutical research presents unique advantages as its physiology in many ways resembles the human physiology, it also has a relatively short generation time, low breeding and maintenance costs, and is available in a wide variety of inbred strains. The ability to genetically modify mouse embryonic stem cells to generate mouse models that better mimic human disease is another advantage. In the present study, a comprehensive phenotypic screening protocol is applied to elucidate the phenotype of a novel mouse knockout model of hepatocyte nuclear factor (HNF) 4-{gamma}. HNF4-{gamma} is expressed in the kidneys, gut, pancreas, and testis. First level of the screen is aimed at general health, morphologic appearance, normal cage behaviour, and gross neurological functions. The second level of the screen looks at metabolic characteristics and lung function. The third level of the screen investigates behaviour more in-depth and the fourth level consists of a thorough pathological characterisation, blood chemistry, haematology, and bone marrow analysis. When compared with littermate wild-type mice (HNF4-{gamma}{sup +/+}), the HNF4-{gamma} knockout (HNF4-{gamma}{sup -/-}) mice had lowered energy expenditure and locomotor activity during night time that resulted in a higher body weight despite having reduced intake of food and water. HNF4-{gamma}{sup -/-} mice were less inclined to build nest and were found to spend more time in a passive state during the forced swim test.

  20. Toll-like receptor 4 knockout alleviates paraquat-induced cardiomyocyte contractile dysfunction through an autophagy-dependent mechanism.

    PubMed

    Wang, Shuyi; Zhu, Xiaoling; Xiong, Lize; Zhang, Yingmei; Ren, Jun

    2016-08-22

    Paraquat, a quarternary nitrogen herbicide, is a toxic prooxidant leading to multi-organ failure including the heart although the underlying mechanism remains poorly understood. This study was designed to examine the role of the innate proinflammatory mediator toll-like receptor 4 (TLR4) in paraquat-induced cardiac contractile anomalies and the underlying mechanisms involved with a focus on autophagy, a conservative machinery governing protein and organelle degradation and recycling for cardiac homeostasis. Wild-type (WT) and TLR4 knockout (TLR4(-/-)) mice were challenged with paraquat (45mg/kg, i.p.) for 48h. Paraquat challenge did not affect mRNA levels of TLR2, TLR4 and TLR9 in WT mice nor did paraquat treatment alter TREM-1 levels. Paraquat challenge elicited cardiac mechanical defects including compromised cardiomyocyte contractile function, intracellular Ca(2+) handling, and overt autophagy as manifested by increased LC3BII-to-LC3BI ratio, Atg5, Atg7 and p62 levels. Interestingly, TLR4 knockout significantly attenuated paraquat-induced cardiac contractile and intracellular Ca(2+) derangement as well as alterations of autophagy markers. Paraquat-elicited changes in cardiac autophagy markers (LC3BII, LC3BII-to-LC3BI ratio and p62) were augmented by lysosomal inhibition using bafilomycin A1 in WT mice. TLR4 knockout significantly attenuated or negated paraquat-elicited increase in LC3BII, LC3BII-to-LC3BI ratio and p62 levels in the presence of lysosomal inhibition. In addition, paraquat challenge promoted phosphorylation of AMPK while suppressing the phosphorylation of mTOR and ULK1 (the autophagy inhibitory Ser(757)), the effects of which were significantly attenuated by TLR4 ablation. In vitro study revealed that AMPK activation using AICAR or mTOR inhibition using rapamycin effectively negated the beneficial cardiomyocyte mechanical effects of TLR4 inhibition (CLI-095) against paraquat toxicity, supporting a permissive role for AMPK-mTOR in TLR4 inhibition

  1. Toll-like receptor 4 knockout alleviates paraquat-induced cardiomyocyte contractile dysfunction through an autophagy-dependent mechanism.

    PubMed

    Wang, Shuyi; Zhu, Xiaoling; Xiong, Lize; Zhang, Yingmei; Ren, Jun

    2016-08-22

    Paraquat, a quarternary nitrogen herbicide, is a toxic prooxidant leading to multi-organ failure including the heart although the underlying mechanism remains poorly understood. This study was designed to examine the role of the innate proinflammatory mediator toll-like receptor 4 (TLR4) in paraquat-induced cardiac contractile anomalies and the underlying mechanisms involved with a focus on autophagy, a conservative machinery governing protein and organelle degradation and recycling for cardiac homeostasis. Wild-type (WT) and TLR4 knockout (TLR4(-/-)) mice were challenged with paraquat (45mg/kg, i.p.) for 48h. Paraquat challenge did not affect mRNA levels of TLR2, TLR4 and TLR9 in WT mice nor did paraquat treatment alter TREM-1 levels. Paraquat challenge elicited cardiac mechanical defects including compromised cardiomyocyte contractile function, intracellular Ca(2+) handling, and overt autophagy as manifested by increased LC3BII-to-LC3BI ratio, Atg5, Atg7 and p62 levels. Interestingly, TLR4 knockout significantly attenuated paraquat-induced cardiac contractile and intracellular Ca(2+) derangement as well as alterations of autophagy markers. Paraquat-elicited changes in cardiac autophagy markers (LC3BII, LC3BII-to-LC3BI ratio and p62) were augmented by lysosomal inhibition using bafilomycin A1 in WT mice. TLR4 knockout significantly attenuated or negated paraquat-elicited increase in LC3BII, LC3BII-to-LC3BI ratio and p62 levels in the presence of lysosomal inhibition. In addition, paraquat challenge promoted phosphorylation of AMPK while suppressing the phosphorylation of mTOR and ULK1 (the autophagy inhibitory Ser(757)), the effects of which were significantly attenuated by TLR4 ablation. In vitro study revealed that AMPK activation using AICAR or mTOR inhibition using rapamycin effectively negated the beneficial cardiomyocyte mechanical effects of TLR4 inhibition (CLI-095) against paraquat toxicity, supporting a permissive role for AMPK-mTOR in TLR4 inhibition

  2. Differential actions of orexin receptors in brainstem cholinergic and monoaminergic neurons revealed by receptor knockouts: implications for orexinergic signaling in arousal and narcolepsy

    PubMed Central

    Kohlmeier, Kristi A.; Tyler, Christopher J.; Kalogiannis, Mike; Ishibashi, Masaru; Kristensen, Morten P.; Gumenchuk, Iryna; Chemelli, Richard M.; Kisanuki, Yaz Y.; Yanagisawa, Masashi; Leonard, Christopher S.

    2013-01-01

    Orexin neuropeptides influence multiple homeostatic functions and play an essential role in the expression of normal sleep-wake behavior. While their two known receptors (OX1 and OX2) are targets for novel pharmacotherapeutics, the actions mediated by each receptor remain largely unexplored. Using brain slices from mice constitutively lacking either receptor, we used whole-cell and Ca2+ imaging methods to delineate the cellular actions of each receptor within cholinergic [laterodorsal tegmental nucleus (LDT)] and monoaminergic [dorsal raphe (DR) and locus coeruleus (LC)] brainstem nuclei—where orexins promote arousal and suppress REM sleep. In slices from OX−/−2 mice, orexin-A (300 nM) elicited wild-type responses in LDT, DR, and LC neurons consisting of a depolarizing current and augmented voltage-dependent Ca2+ transients. In slices from OX−/−1 mice, the depolarizing current was absent in LDT and LC neurons and was attenuated in DR neurons, although Ca2+-transients were still augmented. Since orexin-A produced neither of these actions in slices lacking both receptors, our findings suggest that orexin-mediated depolarization is mediated by both receptors in DR, but is exclusively mediated by OX1 in LDT and LC neurons, even though OX2 is present and OX2 mRNA appears elevated in brainstems from OX−/−1 mice. Considering published behavioral data, these findings support a model in which orexin-mediated excitation of mesopontine cholinergic and monoaminergic neurons contributes little to stabilizing spontaneous waking and sleep bouts, but functions in context-dependent arousal and helps restrict muscle atonia to REM sleep. The augmented Ca2+ transients produced by both receptors appeared mediated by influx via L-type Ca2+ channels, which is often linked to transcriptional signaling. This could provide an adaptive signal to compensate for receptor loss or prolonged antagonism and may contribute to the reduced severity of narcolepsy in single receptor

  3. Glutamate receptor mGlu2 and mGlu3 knockout striata are dopamine supersensitive, with elevated D2(High) receptors and marked supersensitivity to the dopamine agonist (+)PHNO.

    PubMed

    Seeman, Philip; Battaglia, Giuseppe; Corti, Corrado; Corsi, Mauro; Bruno, Valeria

    2009-03-01

    The finding that the mGlu2/3 metabotropic glutamate receptor agonist, LY404039, improves clinical symptoms in schizophrenia warrants a search for a possible interaction between mGlu2/3 receptors and dopamine D2 receptors. Here, this topic is examined in striatal tissue of mice lacking either mGlu2 or mGlu3 receptor. Such mice are known to be behaviorally supersensitive to dopamine receptor agonists. Therefore, to determine the basis of this dopamine supersensitivity, the proportion of dopamine D2(High) receptors was measured in the striata of mGlu2 and mGlu3 receptor knockout mice. The proportion of D2(High) receptors was found to be elevated by 220% in the striata of both knockouts. To measure the functional dopamine supersensitivity, the D2 agonist (+)PHNO was used to stimulate the incorporation of GTP-gamma-S in the striatal homogenates in the presence of drugs that blocked the dopamine D1, D3, and D5 receptors. Compared with control striata, the mGlu2 receptor knockout tissues were 67-fold more sensitive to (+)PHNO, while the mGlu3 receptor knockout tissues were 17-fold more sensitive. These data suggest that group II mGlu receptors-mGlu2 receptors in particular-may normally regulate D2 receptors by reducing the proportion of high-affinity D2 receptors in membranes. Such regulation may contribute to the antipsychotic action of mGlu2/3 receptor agonists. PMID:19084908

  4. Abolished thermal and mechanical antinociception but retained visceral chemical antinociception induced by butorphanol in mu-opioid receptor knockout mice.

    PubMed

    Ide, Soichiro; Minami, Masabumi; Ishihara, Kumatoshi; Uhl, George R; Satoh, Masamichi; Sora, Ichiro; Ikeda, Kazutaka

    2008-06-01

    Butorphanol is hypothesized to induce analgesia via opioid pathways, although the precise mechanisms for its effects remain unknown. In this study, we investigated the role of the mu-opioid receptor (MOP) in thermal, mechanical, and visceral chemical antinociception induced by butorphanol using MOP knockout (KO) mice. Butorphanol-induced thermal antinociception, assessed by the hot-plate and tail-flick tests, was significantly reduced in heterozygous and abolished in homozygous MOP-KO mice compared with wildtype mice. The results obtained from our butorphanol-induced mechanical antinociception experiments, assessed by the Randall-Selitto test, were similar to the results obtained from the thermal antinociception experiments in these mice. Interestingly, however, butorphanol retained its ability to induce significant visceral chemical antinociception, assessed by the writhing test, in homozygous MOP-KO mice. The butorphanol-induced visceral chemical antinociception that was retained in homozygous MOP-KO mice was completely blocked by pretreatment with nor-binaltorphimine, a kappa-opioid receptor (KOP) antagonist. In vitro binding and cyclic adenosine monophosphate assays also showed that butorphanol possessed higher affinity for KOPs and MOPs than for delta-opioid receptors. These results molecular pharmacologically confirmed previous studies implicating MOPs, and partially KOPs, in mediating butorphanol-induced analgesia. PMID:18417173

  5. Enhanced histaminergic neurotransmission and sleep-wake alterations, a study in histamine H3-receptor knock-out mice.

    PubMed

    Gondard, Elise; Anaclet, Christelle; Akaoka, Hidéo; Guo, Rui-Xian; Zhang, Mei; Buda, Colette; Franco, Patricia; Kotani, Hidehito; Lin, Jian-Sheng

    2013-05-01

    Long-term abolition of a brain arousal system impairs wakefulness (W), but little is known about the consequences of long-term enhancement. The brain histaminergic arousal system is under the negative control of H3-autoreceptors whose deletion results in permanent enhancement of histamine (HA) turnover. In order to determine the consequences of enhancement of the histaminergic system, we compared the cortical EEG and sleep-wake states of H3-receptor knockout (H3R-/-) and wild-type mouse littermates. We found that H3R-/-mice had rich phenotypes. On the one hand, they showed clear signs of enhanced HA neurotransmission and vigilance, i.e., a higher EEG θ power during spontaneous W and a greater extent of W or sleep restriction during behavioral tasks, including environmental change, locomotion, and motivation tests. On the other hand, during the baseline dark period, they displayed deficient W and signs of sleep deterioration, such as pronounced sleep fragmentation and reduced cortical slow activity during slow wave sleep (SWS), most likely due to a desensitization of postsynaptic histaminergic receptors as a result of constant HA release. Ciproxifan (H3-receptor inverse agonist) enhanced W in wild-type mice, but not in H3R-/-mice, indicating a functional deletion of H3-receptors, whereas triprolidine (postsynaptic H1-receptor antagonist) or α-fluoromethylhistidine (HA-synthesis inhibitor) caused a greater SWS increase in H3R-/- than in wild-type mice, consistent with enhanced HA neurotransmission. These sleep-wake characteristics and the obesity phenotypes previously reported in this animal model suggest that chronic enhancement of histaminergic neurotransmission eventually compromises the arousal system, leading to sleep-wake, behavioral, and metabolic disorders similar to those caused by voluntary sleep restriction in humans.

  6. Normal sleep homeostasis and lack of epilepsy phenotype in GABA A receptor alpha3 subunit-knockout mice.

    PubMed

    Winsky-Sommerer, R; Knapman, A; Fedele, D E; Schofield, C M; Vyazovskiy, V V; Rudolph, U; Huguenard, J R; Fritschy, J-M; Tobler, I

    2008-06-23

    Thalamo-cortical networks generate specific patterns of oscillations during distinct vigilance states and epilepsy, well characterized by electroencephalography (EEG). Oscillations depend on recurrent synaptic loops, which are controlled by GABAergic transmission. In particular, GABA A receptors containing the alpha3 subunit are expressed predominantly in cortical layer VI and thalamic reticular nucleus (nRT) and regulate the activity and firing pattern of neurons in relay nuclei. Therefore, ablation of these receptors by gene targeting might profoundly affect thalamo-cortical oscillations. Here, we investigated the role of alpha3-GABA A receptors in regulating vigilance states and seizure activity by analyzing chronic EEG recordings in alpha3 subunit-knockout (alpha3-KO) mice. The presence of postsynaptic alpha3-GABA A receptors/gephyrin clusters in the nRT and GABA A-mediated synaptic currents in acute thalamic slices was also examined. EEG spectral analysis showed no difference between genotypes during non rapid-eye movement (NREM) sleep or at waking-NREM sleep transitions. EEG power in the spindle frequency range (10-15 Hz) was significantly lower at NREM-REM sleep transitions in mutant compared with wild-type mice. Enhancement of sleep pressure by 6 h sleep deprivation did not reveal any differences in the regulation of EEG activities between genotypes. Finally, the waking EEG showed a slightly larger power in the 11-13-Hz band in alpha3-KO mice. However, neither behavior nor the waking EEG showed alterations suggestive of absence seizures. Furthermore, alpha3-KO mice did not differ in seizure susceptibility in a model of temporal lobe epilepsy. Strikingly, despite the disruption of postsynaptic gephyrin clusters, whole-cell patch clamp recordings revealed intact inhibitory synaptic transmission in the nRT of alpha3-KO mice. These findings show that the lack of alpha3-GABA(A) receptors is extensively compensated for to preserve the integrity of thalamo

  7. Enhanced Histaminergic Neurotransmission and Sleep-Wake Alterations, a Study in Histamine H3-Receptor Knock-Out Mice

    PubMed Central

    Gondard, Elise; Anaclet, Christelle; Akaoka, Hidéo; Guo, Rui-Xian; Zhang, Mei; Buda, Colette; Franco, Patricia; Kotani, Hidehito; Lin, Jian-Sheng

    2013-01-01

    Long-term abolition of a brain arousal system impairs wakefulness (W), but little is known about the consequences of long-term enhancement. The brain histaminergic arousal system is under the negative control of H3-autoreceptors whose deletion results in permanent enhancement of histamine (HA) turnover. In order to determine the consequences of enhancement of the histaminergic system, we compared the cortical EEG and sleep-wake states of H3-receptor knockout (H3R−/−) and wild-type mouse littermates. We found that H3R−/−mice had rich phenotypes. On the one hand, they showed clear signs of enhanced HA neurotransmission and vigilance, i.e., a higher EEG θ power during spontaneous W and a greater extent of W or sleep restriction during behavioral tasks, including environmental change, locomotion, and motivation tests. On the other hand, during the baseline dark period, they displayed deficient W and signs of sleep deterioration, such as pronounced sleep fragmentation and reduced cortical slow activity during slow wave sleep (SWS), most likely due to a desensitization of postsynaptic histaminergic receptors as a result of constant HA release. Ciproxifan (H3-receptor inverse agonist) enhanced W in wild-type mice, but not in H3R−/−mice, indicating a functional deletion of H3-receptors, whereas triprolidine (postsynaptic H1-receptor antagonist) or α-fluoromethylhistidine (HA-synthesis inhibitor) caused a greater SWS increase in H3R−/− than in wild-type mice, consistent with enhanced HA neurotransmission. These sleep-wake characteristics and the obesity phenotypes previously reported in this animal model suggest that chronic enhancement of histaminergic neurotransmission eventually compromises the arousal system, leading to sleep-wake, behavioral, and metabolic disorders similar to those caused by voluntary sleep restriction in humans. PMID:23303066

  8. Assessment of ethanol consumption and water drinking by NPY Y(2) receptor knockout mice.

    PubMed

    Thiele, Todd E; Naveilhan, Philippe; Ernfors, Patrik

    2004-06-01

    In recent years, pharmacological and genetic evidence have emerged suggesting that neuropeptide Y (NPY) and the NPY Y(1) receptor are involved with neurobiological responses to ethanol. Pharmacological data implicate a role for the NPY Y(2) receptor in ethanol self-administration. The purpose of the present study was to determine if genetic mutation of the Y(2) receptor would modulate ethanol consumption and/or ethanol-induced sedation. Here, we report that mutant mice lacking the NPY Y(2) receptor (Y(2)(-/-)), when maintained on a mixed 50% 129/ SvJ x 50 % Balb/cJ background, drink significantly less of solutions containing 3 or 6% (v/v) ethanol relative to wild-type (Y(2)(+/+)) mice. These mice drink normal amounts of solutions containing sucrose or quinine, have normal blood ethanol clearance, and show normal sensitivity to ethanol-induced sedation. However, Y(2)(-/-) mice that are backcrossed to a Balb/cJ background show normal consumption of ethanol, indicating that the contributions of the NPY Y(2) receptor to ethanol consumption are genetic background dependent. Consistent with previous data suggesting that NPY modulates water drinking, Y(2)(-/-) mice of both genetic backgrounds consume significantly more water than Y(2)(+/+) mice. The present results suggest roles for the NPY Y(2) receptor in the modulation of ethanol and water consumption.

  9. Dysfunctional Presynaptic M2 Receptors in the Presence of Chronically High Acetylcholine Levels: Data from the PRiMA Knockout Mouse

    PubMed Central

    Mohr, Franziska; Krejci, Eric; Zimmermann, Martina; Klein, Jochen

    2015-01-01

    The muscarinic M2 receptor (M2R) acts as a negative feedback regulator in central cholinergic systems. Activation of the M2 receptor limits acetylcholine (ACh) release, especially when ACh levels are increased because acetylcholinesterase (AChE) activity is acutely inhibited. Chronically high ACh levels in the extracellular space, however, were reported to down-regulate M2R to various degrees. In the present study, we used the PRiMA knockout mouse which develops severely reduced AChE activity postnatally to investigate ACh release, and we used microdialysis to investigate whether the function of M2R to reduce ACh release in vivo was impaired in adult PRiMA knockout mice. We first show that striatal and hippocampal ACh levels, while strongly increased, still respond to AChE inhibitors. Infusion or injection of oxotremorine, a muscarinic M2 agonist, reduced ACh levels in wild-type mice but did not significantly affect ACh levels in PRiMA knockout mice or in wild-type mice in which ACh levels were artificially increased by infusion of neostigmine. Scopolamine, a muscarinic antagonist, increased ACh levels in wild-type mice receiving neostigmine, but not in wild-type mice or in PRiMA knockout mice. These results demonstrate that M2R are dysfunctional and do not affect ACh levels in PRiMA knockout mice, likely because of down-regulation and/or loss of receptor-effector coupling. Remarkably, this loss of function does not affect cognitive functions in PRiMA knockout mice. Our results are discussed in the context of AChE inhibitor therapy as used in dementia. PMID:26506622

  10. Specific regions display altered grey matter volume in μ-opioid receptor knockout mice: MRI voxel-based morphometry

    PubMed Central

    Sasaki, Kazumasu; Sumiyoshi, Akira; Nonaka, Hiroi; Kasahara, Yoshiyuki; Ikeda, Kazutaka; Hall, F Scott; Uhl, George R; Watanabe, Masahiko; Kawashima, Ryuta; Sora, Ichiro

    2015-01-01

    BACKGROUND AND PURPOSE μ Opioid receptor knockout (MOP-KO) mice display several behavioural differences from wild-type (WT) littermates including differential responses to nociceptive stimuli. Brain structural changes have been tied to behavioural alterations noted in transgenic mice with targeting of different genes. Hence, we assess the brain structure of MOP-KO mice. EXPERIMENTAL APPROACH Magnetic resonance imaging (MRI) voxel-based morphometry (VBM) and histological methods were used to identify structural differences between extensively backcrossed MOP-KO mice and WT mice. KEY RESULTS MOP-KO mice displayed robust increases in regional grey matter volume in olfactory bulb, several hypothalamic nuclei, periaqueductal grey (PAG) and several cerebellar areas, most confirmed by VBM analysis. The largest increases in grey matter volume were detected in the glomerular layer of the olfactory bulb, arcuate nucleus of hypothalamus, ventrolateral PAG (VLPAG) and cerebellar regions including paramedian and cerebellar lobules. Histological analyses confirm several of these results, with increased VLPAG cell numbers and increased thickness of the olfactory bulb granule cell layer and cerebellar molecular and granular cell layers. CONCLUSIONS AND IMPLICATIONS MOP deletion causes previously undescribed structural changes in specific brain regions, but not in all regions with high MOP receptor densities (e.g. thalamus, nucleus accumbens) or that exhibit adult neurogenesis (e.g. hippocampus). Volume differences in hypothalamus and PAG may reflect behavioural changes including hyperalgesia. Although the precise relationship between volume change and MOP receptor deletion was not determined from this study alone, these findings suggest that levels of MOP receptor expression may influence a broader range of neural structure and function in humans than previously supposed. LINKED ARTICLES This article is part of a themed section on Opioids: New Pathways to Functional Selectivity

  11. 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. PMID:27125304

  12. Hypoglycemia, hyperglucagonemia, and fetoplacental defects in glucagon receptor knockout mice: a role for glucagon action in pregnancy maintenance.

    PubMed

    Ouhilal, Sophia; Vuguin, Patricia; Cui, Lingguang; Du, Xiu-Quan; Gelling, Richard W; Reznik, Sandra E; Russell, Robert; Parlow, Albert F; Karpovsky, Clara; Santoro, Nanette; Charron, Maureen J

    2012-03-01

    Alterations in insulin signaling as well as insulin action predispose to infertility as well as adverse pregnancy outcomes; however, little is known about the role of glucagon signaling in reproduction. The glucagon receptor knockout (Gcgr(-/-)) mouse created by our laboratory was used to define the role of glucagon signaling in maintaining normal reproduction. In this mouse model, lack of glucagon signaling did not alter the hypothalamic-pituitary-ovarian axis. Pregnant Gcgr(-/-) female mice displayed persistent hypoglycemia and hyperglucagonemia. Gcgr(-/-) pregnancies were associated with decreased fetal weight, increased late-gestation fetal demise, and significant abnormalities of placentation. Gcgr(-/-) placentas contained areas of extensive mineralization, fibrinoid necrosis, narrowing of the vascular channels, and a thickened interstitium associated with trophoblast hyperplasia. Absent glucagon signaling did not alter glycogen content in Gcgr(-/-) placentas but significantly downregulated genes that control growth, adrenergic signaling, vascularization, oxidative stress, and G protein-coupled receptors. Our data suggest that, similarly to insulin, glucagon action contributes to normal female reproductive function.

  13. Investigation of nasal CO₂ receptor transduction mechanisms in wild-type and GC-D knockout mice.

    PubMed

    Kenemuth, Jessica K; Hennessy, Shane P; Hanson, Ryan J; Hensler, Allison J; Coates, E Lee

    2013-11-01

    The main olfactory system of mice contains a small subset of olfactory sensory neurons (OSNs) that are stimulated by CO₂. The objective of this study was to record olfactory receptor responses to a range of CO₂ concentrations to further elucidate steps in the proposed CO₂ transduction pathway in mice. Electro-olfactograms (EOGs) were recorded before and after inhibiting specific steps in the CO₂ transduction pathway with topically applied inhibitors. Inhibition of extracellular carbonic anhydrase (CA) did not significantly affect EOG responses to CO₂ but did decrease EOG responses to several control odorants. Inhibition of intracellular CA or cyclic nucleotide-gated channels attenuated EOG responses to CO₂, confirming the role of these components in CO₂ sensing in mice. We also show that, like canonical OSNs, CO₂-sensitive OSNs depend on Ca²⁺-activated Cl⁻ channels for depolarization of receptor neurons. Lastly, we found that guanylyl cyclase-D knockout mice were still able to respond to CO₂, indicating that other pathways may exist for the detection of low concentrations of nasal CO₂. We discuss these findings as they relate to previous studies on CO₂-sensitive OSNs in mice and other animals.

  14. Development of Accelerated Coronary Atherosclerosis Model Using Low Density Lipoprotein Receptor Knock-Out Swine with Balloon Injury

    PubMed Central

    Ogita, Manabu; Miyauchi, Katsumi; Onishi, Akira; Tsuboi, Shuta; Wada, Hideki; Konishi, Hirokazu; Naito, Ryo; Dohi, Tomotaka; Kasai, Takatoshi; Kojima, Yuko; Schwartz, Robert S.; Daida, Hiroyuki

    2016-01-01

    Background Several animal models have facilitated the evaluation and pathological understanding of atherosclerosis, but a definitive animal model of coronary atherosclerosis is not available. We therefore developed low density lipoprotein receptor knockout (LDLR-KO) pigs with hypercholesterolemia, a model which rapidly developed coronary atherosclerosis following balloon injury. Methods and Results We deleted LDLR exon regions from cultured porcine fetal fibroblasts and cloned LDLR knockout (LDLR-KO) embryos microinjecting fetal fibroblast nuclei into enucleated oocytes. Twelve LDLR-KO pigs were fed a 2.0% cholesterol and 20% fat diet. Baseline serum LDL cholesterol level was 510.0±86.1 mg/dL. Balloon injury was created in 46 coronary segments and necropsy were obtained 2, 4, 8 and 12 weeks later. Coronary artery sections were reviewed to evaluate lesion progression. We found lipid accumulation with foam cells and inflammatory cells beginning four weeks after balloon injury. The mean ratio of macrophages to plaque area was significantly higher in the four- weeks and eight-week animals compared with those at 2-weeks (8.79% ± 5.98% and 17.00% ± 10.38% vs. 1.14% ± 1.88%, P < 0.0001). At 12 weeks the ratio decreased toward the level at 2 week level (4.00% ± 4.56%, P = 0.66 vs. baseline). Advanced coronary atherosclerotic lesions contained lipid pools at eight-weeks with fibrous components beginning at 12 weeks. Conclusions We developed a model of rapid coronary atherosclerosis using LDLR KO pigs with balloon injury. This model may be useful for preclinical evaluation of medication or devices, and may also help investigate mechanisms of plaque progression. PMID:27631974

  15. Peripheral benzodiazepine receptor/translocator protein global knock-out mice are viable with no effects on steroid hormone biosynthesis.

    PubMed

    Tu, Lan N; Morohaku, Kanako; Manna, Pulak R; Pelton, Susanne H; Butler, W Ronald; Stocco, Douglas M; Selvaraj, Vimal

    2014-10-01

    Translocator protein (TSPO), previously known as the peripheral benzodiazepine receptor, is a mitochondrial outer membrane protein implicated as essential for cholesterol import to the inner mitochondrial membrane, the rate-limiting step in steroid hormone biosynthesis. Previous research on TSPO was based entirely on in vitro experiments, and its critical role was reinforced by an early report that claimed TSPO knock-out mice were embryonic lethal. In a previous publication, we examined Leydig cell-specific TSPO conditional knock-out mice that suggested TSPO was not required for testosterone production in vivo. This raised controversy and several questions regarding TSPO function. To examine the definitive role of TSPO in steroidogenesis and embryo development, we generated global TSPO null (Tspo(-/-)) mice. Contrary to the early report, Tspo(-/-) mice survived with no apparent phenotypic abnormalities and were fertile. Examination of adrenal and gonadal steroidogenesis showed no defects in Tspo(-/-) mice. Adrenal transcriptome comparison of gene expression profiles showed that genes involved in steroid hormone biosynthesis (Star, Cyp11a1, and Hsd3b1) were unchanged in Tspo(-/-) mice. Adrenocortical ultrastructure illustrated no morphological alterations in Tspo(-/-) mice. In an attempt to correlate our in vivo findings to previously used in vitro models, we also determined that siRNA knockdown or the absence of TSPO in different mouse and human steroidogenic cell lines had no effect on steroidogenesis. These findings directly refute the dogma that TSPO is indispensable for steroid hormone biosynthesis and viability. By amending the current model, this study advances our understanding of steroidogenesis with broad implications in biology and medicine.

  16. Inflammatory bone loss in experimental periodontitis induced by Aggregatibacter actinomycetemcomitans in interleukin-1 receptor antagonist knockout mice.

    PubMed

    Izawa, A; Ishihara, Y; Mizutani, H; Kobayashi, S; Goto, H; Okabe, E; Takeda, H; Ozawa, Y; Kamiya, Y; Sugita, Y; Kubo, K; Kamei, H; Kikuchi, T; Mitani, A; Hayashi, J; Nishihara, T; Maeda, H; Noguchi, T

    2014-05-01

    The interleukin-1 receptor antagonist (IL-1Ra) binds to IL-1 receptors and inhibits IL-1 activity. However, it is not clear whether IL-1Ra plays a protective role in periodontal disease. This study was undertaken to compare experimental periodontitis induced by Aggregatibacter actinomycetemcomitans in IL-1Ra knockout (KO) mice and wild-type (WT) mice. Computed tomography (CT) analysis and hematoxylin-and-eosin (H&E) and tartrate-resistant acid phosphatase (TRAP) staining were performed. In addition, osteoblasts were isolated; the mRNA expression of relevant genes was assessed by real-time quantitative PCR (qPCR); and calcification was detected by Alizarin Red staining. Infected IL-1Ra KO mice exhibited elevated (P, <0.05) levels of antibody against A. actinomycetemcomitans, bone loss in furcation areas, and alveolar fenestrations. Moreover, protein for tumor necrosis factor alpha (TNF-α) and IL-6, mRNA for macrophage colony-stimulating factor (M-CSF), and receptor activator of NF-κB ligand (RANKL) in IL-1Ra KO mouse osteoblasts stimulated with A. actinomycetemcomitans were increased (P, <0.05) compared to in WT mice. Alkaline phosphatase (ALP), bone sialoprotein (BSP), osteocalcin (OCN)/bone gla protein (BGP), and runt-related gene 2 (Runx2) mRNA levels were decreased (P, <0.05). IL-1α mRNA expression was increased, and calcification was not observed, in IL-1 Ra KO mouse osteoblasts. In brief, IL-1Ra deficiency promoted the expression of inflammatory cytokines beyond IL-1 and altered the expression of genes involved in bone resorption in A. actinomycetemcomitans-infected osteoblasts. Alterations consistent with rapid bone loss in infected IL-Ra KO mice were also observed for genes expressed in bone formation and calcification. In short, these data suggest that IL-1Ra may serve as a potential therapeutic drug for periodontal disease.

  17. Inflammatory bone loss in experimental periodontitis induced by Aggregatibacter actinomycetemcomitans in interleukin-1 receptor antagonist knockout mice.

    PubMed

    Izawa, A; Ishihara, Y; Mizutani, H; Kobayashi, S; Goto, H; Okabe, E; Takeda, H; Ozawa, Y; Kamiya, Y; Sugita, Y; Kubo, K; Kamei, H; Kikuchi, T; Mitani, A; Hayashi, J; Nishihara, T; Maeda, H; Noguchi, T

    2014-05-01

    The interleukin-1 receptor antagonist (IL-1Ra) binds to IL-1 receptors and inhibits IL-1 activity. However, it is not clear whether IL-1Ra plays a protective role in periodontal disease. This study was undertaken to compare experimental periodontitis induced by Aggregatibacter actinomycetemcomitans in IL-1Ra knockout (KO) mice and wild-type (WT) mice. Computed tomography (CT) analysis and hematoxylin-and-eosin (H&E) and tartrate-resistant acid phosphatase (TRAP) staining were performed. In addition, osteoblasts were isolated; the mRNA expression of relevant genes was assessed by real-time quantitative PCR (qPCR); and calcification was detected by Alizarin Red staining. Infected IL-1Ra KO mice exhibited elevated (P, <0.05) levels of antibody against A. actinomycetemcomitans, bone loss in furcation areas, and alveolar fenestrations. Moreover, protein for tumor necrosis factor alpha (TNF-α) and IL-6, mRNA for macrophage colony-stimulating factor (M-CSF), and receptor activator of NF-κB ligand (RANKL) in IL-1Ra KO mouse osteoblasts stimulated with A. actinomycetemcomitans were increased (P, <0.05) compared to in WT mice. Alkaline phosphatase (ALP), bone sialoprotein (BSP), osteocalcin (OCN)/bone gla protein (BGP), and runt-related gene 2 (Runx2) mRNA levels were decreased (P, <0.05). IL-1α mRNA expression was increased, and calcification was not observed, in IL-1 Ra KO mouse osteoblasts. In brief, IL-1Ra deficiency promoted the expression of inflammatory cytokines beyond IL-1 and altered the expression of genes involved in bone resorption in A. actinomycetemcomitans-infected osteoblasts. Alterations consistent with rapid bone loss in infected IL-Ra KO mice were also observed for genes expressed in bone formation and calcification. In short, these data suggest that IL-1Ra may serve as a potential therapeutic drug for periodontal disease. PMID:24566623

  18. Estrogen receptor function as revealed by knockout studies: neuroendocrine and behavioral aspects.

    PubMed

    Rissman, E F; Wersinger, S R; Taylor, J A; Lubahn, D B

    1997-06-01

    Estrogens are an important class of steroid hormones, involved in the development of brain, skeletal, and soft tissues. These hormones influence adult behaviors, endocrine state, and a host of other physiological functions. Given the recent cloning of a second estrogen receptor (ER) cDNA (the ER beta), work on alternate spliced forms of ER alpha, and the potential for membrane estrogen receptors, an animal with a null background for ER alpha function is invaluable for distinguishing biological responses of estrogens working via the ER alpha protein and those working via another ER protein. Data generated to date, and reviewed here, indicate that there are profound ramifications of the ER alpha disruption on behavior and neuroendocrine function. First, data on plasma levels of estradiol (E2), testosterone (T), and luteinizing hormone (LH) in wild-type (WT) versus ER alpha- mice confirm that ER alpha is essential in females for normal regulation of the hypothalamic-pituitary gonadal axis. Second, ovariectomized female ER alpha- mice do not display sexual receptivity when treated with a hormonal regime of estrogen and progesterone that induces receptivity in WT littermates. Finally, male sexual behaviors are disrupted in ER alpha- animals. Given decades of data on these topics our findings may seem self-evident. However, these data represent the most direct test currently possible of the specific role of the ER alpha protein on behavior and neuroendocrinology. The ER alpha- mouse can be used to ascertain the specific functions of ER alpha, to suggest functions for the other estrogen receptors, and to study indirect effects of ER alpha on behavior via actions on other receptors, neurotransmitters, and neuropeptides.

  19. Knockout of Angiotensin AT2 receptors accelerates healing but impairs quality

    PubMed Central

    Faghih, Mahya; Hosseini, Sayed M.; Smith, Barbara; Ansari, Amir Mehdi.; Lay, Frank; Ahmed, Ali Karim; Inagami, Tedashi; Marti, Guy P.; Harmon, John W.; Walston, Jeremy D.; Abadir, Peter M.

    2015-01-01

    Wounds are among the most common, painful, debilitating and costly conditions in older adults. Disruption of the angiotensin type 1 receptors (AT1R), has been associated with impaired wound healing, suggesting a critical role for AT1R in this repair process. Biological functions of angiotensin type 2 receptors (AT2R) are less studied. We investigated effects of genetically disrupting AT2R on rate and quality of wound healing. Our results suggest that AT2R effects on rate of wound closure depends on the phase of wound healing. We observed delayed healing during early phase of wound healing (inflammation). An accelerated healing rate was seen during later stages (proliferation and remodeling). By day 12, fifty percent of AT2R−/− mice had complete wound closure as compared to none in either C57/BL6 or AT1R−/− mice. There was a significant increase in AT1R, TGFβ1 and TGFβ2 expression during the proliferative and remodeling phases in AT2R−/− mice. Despite the accelerated closure rate, AT2R−/− mice had more fragile healed skin. Our results suggest that in the absence of AT2R, wound healing rate is accelerated, but yielded worse skin quality. Elucidating the contribution of both of the angiotensin receptors may help fine tune future intervention aimed at wound repair in older individuals. PMID:26727887

  20. Alpha-Ca2+/calmodulin-dependent protein kinase II contributes to the developmental programming of anxiety in serotonin receptor 1A knock-out mice.

    PubMed

    Lo Iacono, Luisa; Gross, Cornelius

    2008-06-11

    Mice lacking the serotonin receptor 1A [Htr1aknock-out (Htr1a(KO))] display increased innate and conditioned anxiety-related behavior. Expression of the receptor in the mouse forebrain during development is sufficient to restore normal anxiety-related behavior to knock-out mice, demonstrating a role for serotonin in the developmental programming of anxiety circuits. However, the precise developmental period as well as the signaling pathways and neural substrates involved in this phenomenon are unknown. Here, we show that pharmacological blockade of the receptor from postnatal day 13 (P13)-P34 is sufficient to reproduce the knock-out phenotype in adulthood, thus defining a role for serotonin in the maturation and refinement of anxiety circuits during a limited postnatal period. Furthermore, we identify increases in the phosphorylation of alpha-Ca(2+)/calmodulin-dependent protein kinase II (alphaCaMKII) at threonine 286 in the hippocampus of young Htr1a(KO) mice under anxiety-provoking conditions. Increases in alphaCaMKII phosphorylation were most pronounced in the CA1 region of the hippocampus and were localized to the extrasynaptic compartment, consistent with a tissue-specific effect of the receptor. No changes in alphaCaMKII phosphorylation were found in adult knock-out mice, suggesting a transient role of alphaCaMKII as a downstream target of the receptor. Finally, the anxiety phenotype was abolished when knock-out mice were crossed to mice in which alphaCaMKII phosphorylation was compromised by the heterozygous mutation of threonine 286 into alanine. These findings suggest that modulation of alphaCaMKII function by serotonin during a restricted postnatal period contributes to the developmental programming of anxiety-related behavior. PMID:18550767

  1. A serotonin receptor 1A containing complex in hippocampus of PWD/PhJ mice is linked to training effects in the Barnes maze.

    PubMed

    Heo, Seok; Patil, Sudarshan S; Jung, Gangsoo; Höger, Harald; Lubec, Gert

    2011-01-01

    Although the involvement of the serotonin 1A receptor (5-HT(1A) R) in memory has been shown by several groups there is no information about the 5-HT(1A) R complex but rather the monomeric form. Moreover, there is insufficient information on the characterization of the antigen, the 5-HT(1A) R. PWD/PhJ mice, a wild-caught strain that was inbred at The Jackson Laboratories were used for the experiments. The Barnes maze (BM) paradigm for the evaluation of spatial memory was chosen because of experience with this setting in our laboratory. Mice were sacrificed 6 h following the probe trial on day 12, hippocampi were extirpated, proteins extracted and run on blue native gels with subsequent immunoblotting with a specific antibody against the mouse 5-HT(1A) R. Densitometry of the single band from the immunoblots was carried out. The receptor from the complex was identified by mass spectrometry (nano-LC-ESI-MS/MS). A serotonin receptor 1A complex was identified by immunoblotting at the apparent molecular weight of 480 kDa indicating the presence of a homopolymer as denaturation only revealed a single band at approx. 50 kDa. 5-HT(1A) R levels were significantly higher in the trained group as compared to yoked controls. The hippocampal 5-HT(1A) R of the trained group was unambiguously identified. Taken together, a serotonin receptor 1A homopolymer is associated with memory training effects in the BM using PWD/PhJ mice. This observation shows that a specific complex rather than a receptor subunit as previously shown is involved in memory process and the receptor protein was characterized.

  2. Role of spinal 5-HT receptors in cutaneous hypersensitivity induced by REM sleep deprivation.

    PubMed

    Wei, Hong; Ma, Ainiu; Wang, Yong-Xiang; Pertovaara, Antti

    2008-06-01

    Previous studies indicate that rapid eye movement (REM) sleep deprivation facilitates pain sensitivity. Since serotoninergic raphe neurons are involved both in regulation of sleep and descending pain modulation, we studied whether spinal 5-HT receptors have a role in sleep deprivation-induced facilitation of pain-related behavior. REM sleep deprivation of 48h was induced by the flower pot method in the rat. The pain modulatory influence of various serotoninergic compounds administered intrathecally was assessed by determining limb withdrawal response to monofilaments. REM sleep deprivation produced a marked hypersensitivity. Sleep deprivation-induced hypersensitivity and normal sensitivity in controls were reduced both by a 5-HT(1A) receptor antagonist (WAY-100635) and a 5-HT(2C) receptor antagonist (RS-102221). An antagonist of the 5-HT(3) receptor (LY-278584) failed to modulate hypersensitivity in sleep-deprived or control animals. Paradoxically, sensitivity in sleep-deprived and control animals was reduced not only by a 5-HT(1A) receptor antagonist but also by a 5-HT(1A) receptor agonist (8-OHDPAT). The results indicate that serotoninergic receptors in the spinal cord have a complex role in the control of sleep-deprivation induced cutaneous hypersensitivity as well as baseline sensitivity in control conditions. While endogenous serotonin acting on 5-HT(1A) and 5-HT(2C) receptors may facilitate mechanical sensitivity in animals with a sleep deprivation-induced hypersensitivity as well as in controls, increased activation of spinal 5-HT(1A) receptors by an exogenous agonist leads to suppression of mechanical sensitivity in both conditions. Spinal 5-HT(3) receptors do not contribute to cutaneous hypersensitivity induced by sleep deprivation.

  3. Serotonin Receptors in the Medulla Oblongata of the Human Fetus and Infant: The Analytic Approach of the International Safe Passage Study

    PubMed Central

    Folkerth, Rebecca D.; Paterson, David S.; Broadbelt, Kevin G.; Dan Zaharie, S.; Hewlett, Richard H.; Dempers, Johan J.; Burger, Elsie; Wadee, Shabbir; Schubert, Pawel; Wright, Colleen; Sens, Mary Ann; Nelsen, Laura; Randall, Bradley B.; Tran, Hoa; Geldenhuys, Elaine; Elliott, Amy J.; Odendaal, Hein J.; Kinney, Hannah C.

    2016-01-01

    The Safe Passage Study is an international, prospective study of approximately 12 000 pregnancies to determine the effects of prenatal alcohol exposure (PAE) upon stillbirth and the sudden infant death syndrome (SIDS). A key objective of the study is to elucidate adverse effects of PAE upon binding to serotonin (5-HT) 1A receptors in brainstem homeostatic networks postulated to be abnormal in unexplained stillbirth and/or SIDS. We undertook a feasibility assessment of 5-HT1A receptor binding using autoradiography in the medulla oblongata (6 nuclei in 27 cases). 5-HT1A binding was compared to a reference dataset from the San Diego medical examiner’s system. There was no adverse effect of postmortem interval ≤100 h. The distribution and quantitated values of 5-HT1A binding in Safe Passage Study cases were essentially identical to those in the reference dataset, and virtually identical between stillbirths and live born fetal cases in grossly non-macerated tissues. The pattern of binding was present at mid-gestation with dramatic changes in binding levels in the medullary 5-HT nuclei over the second half of gestation; there was a plateau at lower levels in the neonatal period and into infancy. This study demonstrates feasibility of 5-HT1A binding analysis in the medulla in the Safe Passage Study. PMID:27634962

  4. Upregulation of Cannabinoid Type 1 Receptors in Dopamine D2 Receptor Knockout Mice Is Reversed by Chronic Forced Ethanol Consumption

    SciTech Connect

    Thanos, P.K.; Wang, G.; Thanos, P.K.; Gopez, V.; Delis, F.; Michaelides, M.; Grand, D.K.; Wang, G.-J.; Kunos, G.; Volkow, N.D.

    2011-01-01

    The anatomical proximity of the cannabinoid type 1 (CNR1/CB1R) and the dopamine D2 receptors (DRD2), their ability to form CB1R-DRD2 heteromers, their opposing roles in locomotion, and their involvement in ethanol's reinforcing and addictive properties prompted us to study the levels and distribution of CB1R after chronic ethanol intake, in the presence and absence of DRD2. We monitored the drinking patterns and locomotor activity of Drd2+/+ and Drd2-/- mice consuming either water or a 20% (v/v) ethanol solution (forced ethanol intake) for 6 months and used the selective CB1 receptor antagonist [{sup 3}H]SR141716A to quantify CB1R levels in different brain regions with in vitro receptor autoradiography. We found that the lack of DRD2 leads to a marked upregulation (approximately 2-fold increase) of CB1R in the cerebral cortex, the caudate-putamen, and the nucleus accumbens, which was reversed by chronic ethanol intake. The results suggest that DRD2-mediated dopaminergic neurotransmission and chronic ethanol intake exert an inhibitory effect on cannabinoid receptor expression in cortical and striatal regions implicated in the reinforcing and addictive properties of ethanol.

  5. The role of dorsal raphe nucleus serotonergic and non-serotonergic neurons, and of their receptors, in regulating waking and rapid eye movement (REM) sleep.

    PubMed

    Monti, Jaime M

    2010-10-01

    Based on electrophysiological, neurochemical, genetic and neuropharmacological approaches it is currently accepted that serotonin (5-HT) functions to promote waking (W) and to inhibit rapid-eye movement sleep (REMS). The serotonin-containing neurons of the dorsal raphe nucleus (DRN) provide part of the serotonergic innervation of the telencephalon, diencephalon, mesencephalon and rhombencephalon of laboratory animals and man. The DRN has been subdivided into several clusters on the basis of differences in cellular morphology, expression of other neurotransmitters and afferent and efferent connections. These differences among subpopulations of 5-HT neurons may have important implications for neural mechanisms underlying 5-HT modulation of sleep and waking. The DRN contains 5-HT and non-5-HT neurons. The latter express a variety of substances including dopamine, γ-aminobutyric acid (GABA) and glutamate. In addition, nitric oxide and a number of neuropeptides have been characterized in the DRN. Available evidence tends to indicate that non-5-HT cells contribute to the regulation of the activity of 5-HT neurons during the sleep-wake cycle through local circuits and/or their mediation of the effects of afferent inputs. Mutant mice that do not express 5-HT(1A) or 5-HT(1B) receptor exhibit greater amounts of REMS than their wild-type couterparts. 5-HT(2A) and 5-HT(2C) receptor knockout mice show a significant increase of W and a reduction of slow wave sleep that is related, at least in part, to the increased release of norepinephrine and dopamine. A normal circadian sleep pattern is observed in 5-HT(7) receptor knockout mice; however, the mutants spend less time in REMS. Local microinjection of 5-HT(1B), 5-HT(2A/2C), 5-HT(3) and 5-HT(7) receptor agonists into the DRN selectively suppresses REMS in the rat. In contrast, microinjection of 5-HT(1A) receptor agonists promotes REMS. Similarly, local administration of the melanin-concentrating hormone or the GABA(A) receptor

  6. Increased frequencies of micronucleated reticulocytes and T-cell receptor mutation in Aldh2 knockout mice exposed to acetaldehyde.

    PubMed

    Kunugita, Naoki; Isse, Toyohi; Oyama, Tsunehiro; Kitagawa, Kyoko; Ogawa, Masanori; Yamaguchi, Tetsunosuke; Kinaga, Tsuyoshi; Kawamoto, Toshihiro

    2008-02-01

    Aldehyde dehydrogenase-2 (ALDH2) metabolizes acetaldehyde produced from ethanol into acetate and plays a major role in the oxidation of acetaldehyde in vivo. About half of all Japanese people have inactive ALDH2. We generated homozygous Aldh2 null (Aldh2-/-) mice by gene targeting knockout as a model of ALDH2-deficient humans. To investigate the mutagenicity of acetaldehyde, a micronucleus assay and a T-cell receptor (TCR) gene mutation assay were performed in Aldh2-/- mice and wild-type (Aldh2 +/+) mice exposed to acetaldehyde. The mice were continuously exposed to 125 and 500 ppm of acetaldehyde vapor for 2 weeks. Another group was orally administered 100 mg/kg once a day for 2 weeks continuously. The mice were killed after 2 weeks of exposure to acetaldehyde, and the frequency of micronucleated reticulocytes was measured by flow cytometry. We also observed the incidence of TCR gene mutations in T-lymphocytes by measuring the variant CD3(-CD4+) expression by flow cytometry. The frequency of micronucleated reticulocytes induced by acetaldehyde was significantly increased in Aldh2 -/- mice, but not in Aldh2 +/+ mice. TCR mutant frequency was also associated with acetaldehyde exposure in Aldh2-/ - mice, especially after oral administration; however, it was not associated with acetaldehyde exposure in Aldh2 +/+ mice. In conclusion, Aldh2 -/- mice showed high sensitivity in the micronuclei and TCR mutation assays compared with Aldh2 +/+ mice after exposure to acetaldehyde. PMID:18303182

  7. Metabolic alterations due to caloric restriction and every other day feeding in normal and growth hormone receptor knockout mice.

    PubMed

    Westbrook, Reyhan; Bonkowski, Michael S; Arum, Oge; Strader, April D; Bartke, Andrzej

    2014-01-01

    Mutations causing decreased somatotrophic signaling are known to increase insulin sensitivity and extend life span in mammals. Caloric restriction and every other day (EOD) dietary regimens are associated with similar improvements to insulin signaling and longevity in normal mice; however, these interventions fail to increase insulin sensitivity or life span in growth hormone receptor knockout (GHRKO) mice. To investigate the interactions of the GHRKO mutation with caloric restriction and EOD dietary interventions, we measured changes in the metabolic parameters oxygen consumption (VO2) and respiratory quotient produced by either long-term caloric restriction or EOD in male GHRKO and normal mice. GHRKO mice had increased VO2, which was unaltered by diet. In normal mice, EOD diet caused a significant reduction in VO2 compared with ad libitum (AL) mice during fed and fasted conditions. In normal mice, caloric restriction increased both the range of VO2 and the difference in minimum VO2 between fed and fasted states, whereas EOD diet caused a relatively static VO2 pattern under fed and fasted states. No diet significantly altered the range of VO2 of GHRKO mice under fed conditions. This provides further evidence that longevity-conferring diets cause major metabolic changes in normal mice, but not in GHRKO mice. PMID:23833202

  8. Liver protein profiles in insulin receptor-knockout mice reveal novel molecules involved in the diabetes pathophysiology.

    PubMed

    Capuani, Barbara; Della-Morte, David; Donadel, Giulia; Caratelli, Sara; Bova, Luca; Pastore, Donatella; De Canio, Michele; D'Aguanno, Simona; Coppola, Andrea; Pacifici, Francesca; Arriga, Roberto; Bellia, Alfonso; Ferrelli, Francesca; Tesauro, Manfredi; Federici, Massimo; Neri, Anna; Bernardini, Sergio; Sbraccia, Paolo; Di Daniele, Nicola; Sconocchia, Giuseppe; Orlandi, Augusto; Urbani, Andrea; Lauro, Davide

    2015-05-01

    Liver has a principal role in glucose regulation and lipids homeostasis. It is under a complex control by substrates such as hormones, nutrients, and neuronal impulses. Insulin promotes glycogen synthesis, lipogenesis, and lipoprotein synthesis and inhibits gluconeogenesis, glycogenolysis, and VLDL secretion by modifying the expression and enzymatic activity of specific molecules. To understand the pathophysiological mechanisms leading to metabolic liver disease, we analyzed liver protein patterns expressed in a mouse model of diabetes by proteomic approaches. We used insulin receptor-knockout (IR(-/-)) and heterozygous (IR(+/-)) mice as a murine model of liver metabolic dysfunction associated with diabetic ketoacidosis and insulin resistance. We evaluated liver fatty acid levels by microscopic examination and protein expression profiles by orthogonal experimental strategies using protein 2-DE MALDI-TOF/TOF and peptic nLC-MS/MS shotgun profiling. Identified proteins were then loaded into Ingenuity Pathways Analysis to find possible molecular networks. Twenty-eight proteins identified by 2-DE analysis and 24 identified by nLC-MS/MS shotgun were differentially expressed among the three genotypes. Bioinformatic analysis revealed a central role of high-mobility group box 1/2 and huntigtin never reported before in association with metabolic and related liver disease. A different modulation of these proteins in both blood and hepatic tissue further suggests their role in these processes. These results provide new insight into pathophysiology of insulin resistance and hepatic steatosis and could be useful in identifying novel biomarkers to predict risk for diabetes and its complications.

  9. Sex-related neurogenesis decrease in hippocampal dentate gyrus with depressive-like behaviors in sigma-1 receptor knockout mice.

    PubMed

    Sha, Sha; Hong, Juan; Qu, Wei-Jun; Lu, Zi-Hong; Li, Lin; Yu, Wen-Feng; Chen, Ling

    2015-08-01

    Male sigma-1 receptor knockout (σ1R(-/-)) mice showed depressive-like phenotype with deficit in the survival of newly generated neuronal cells in the hippocampal dentate gyrus (DG), but female σ1R(-/-) mice did not. The level of serum estradiol (E2) at proestrus or diestrus did not differ between female σ1R(-/-) mice and wild-type (WT) mice. Ovariectomized (OVX) female σ1R(-/-) mice, but not WT mice, presented the same depressive-like behaviors and neurogenesis decrease as male σ1R(-/-) mice. Treatment of male σ1R(-/-) mice with E2 could alleviate the depressive-like behaviors and rescue the neurogenesis decrease. In addition, E2 could correct the decline in the density of NMDA-activated current (INMDA) in granular cells of DG and the phosphorylation of NMDA receptor (NMDAr) subtype 2B (NR2B) in male σ1R(-/-) mice, which was associated with the elevation of Src phosphorylation. The neuroprotection and antidepressant effects of E2 in male σ1R(-/-) mice were blocked by the inhibitor of Src or NR2B. The NMDAr agonist showed also the neuroprotection and antidepressant effects in male σ1R(-/-) mice, which were insensitive to the Src inhibitor. On the other hand, either the deprivation of E2 or the inhibition of Src in female σ1R(-/-) mice rather than WT mice led to a distinct decline in INMDA and NR2B phosphorylation. Similarly, the Src inhibitor could cause neurogenesis decrease and depressive-like behaviors in female σ1R(-/-) mice, but not in WT mice. These results indicate that the σ1R deficiency impairs neurogenesis leading to a depressive-like phenotype, which is alleviated by the neuroprotection of E2.

  10. Hippocampal neurofibromin and amyloid precursor protein expression in dopamine D3 receptor knock-out mice following passive avoidance conditioning.

    PubMed

    D'Amico, Agata Grazia; Castorina, Alessandro; Leggio, Gian Marco; Drago, Filippo; D'Agata, Velia

    2013-03-01

    Passive avoidance (PA) conditioning is a fear motivated task able to initiate a cascade of altered gene expression within the hippocampus, a structure critical to learning and memory. We have previously shown that neurofibromin (NF1) and amyloid precursor protein (APP), two genes implicated in cognitive function, are differentially expressed in brain of dopamine D3 receptor knock-out mice (D(3)R(-/-)), suggesting that the receptor might have a role in their trascriptional regulation. Here in this study, we hypothesized that during acquisition of PA conditioning the expression of NF1 and APP genes could be influenced by D(3)Rs. To address this issue, we analyzed the expression of NF1 and APP in the hippocampus of both wild-type (WT) and D(3)R(-/-) mice subjected to the single trial step-through PA paradigm. Our finding demonstrated that (1) D(3)R(-/-) mice exhibit increased cognitive performance as compared to WT mice in the step-through PA trial; (2) acquisition of PA increased D(3)R and NF1, but not APP expression in WT mice hippocampus; (3) PA-driven NF1 induction in WT was abrogated in D(3)R(-/-) mice and finally that (4) the heightened basal APP expression observed in naive D(3)R(-/-) mice was totally reversed by acquisition of PA. In conclusion, the present finding show for the first time that both D(3)R and NF1 genes are upregulated following PA conditioning and suggest that hippocampal D(3)Rs might be relevant to NF1 transcriptional regulation in the hippocampus.

  11. Colonic mucosal DNA methylation, immune response, and microbiome patterns in Toll-like receptor 2-knockout mice

    PubMed Central

    Kellermayer, Richard; Dowd, Scot E.; Harris, R. Alan; Balasa, Alfred; Schaible, Tiffany D.; Wolcott, Randy D.; Tatevian, Nina; Szigeti, Reka; Li, Zhijie; Versalovic, James; Smith, C. Wayne

    2011-01-01

    The connection between intestinal microbiota and host physiology is increasingly becoming recognized. The details of this dynamic interaction, however, remain to be explored. Toll-like receptor 2 (Tlr2) is important for its role in bacterial recognition, intestinal inflammation, and obesity-related metabolic changes. Therefore, we sought to determine the epigenomic and metagenomic consequences of Tlr2 deficiency in the colonic mucosa of mice to gain insights into biological pathways that shape the interface between the gut microbiota and the mammalian host. Colonic mucosa from wild type (WT) and Tlr2−/− C57BL/6 mice was interrogated by microarrays specific for DNA methylation and gene expression. The mucosal microbiome was studied by next-generation pyrosequencing of bacterial 16S rRNA. The expression of genes involved in immune processes was significantly modified by the absence of Tlr2, a number of which correlated with DNA methylation changes. The epigenomic and transcriptomic modifications associated with alteration in mucosal microbial composition. Several bacterial species, including members of the Firmicutes were significantly different in abundance between WT and Tlr2−/− animals. This manuscript highlights the intimate interrelationships between expression of immune-related genes and immunity pathways in the host with compositional and functional differences of the mammalian microbiome.—Kellermayer, R., Dowd, S. E., Harris, R. A., Balasa, A., Schaible, T. D., Wolcott, R. D., Tatevian, N., Szigeti, R., Li, Z., Versalovic, J., Smith, C. W. Colonic mucosal DNA methylation, immune response, and microbiome patterns in Toll-like receptor 2-knockout mice. PMID:21228220

  12. Progesterone receptor knockout mice have an improved glucose homeostasis secondary to -cell proliferation

    NASA Astrophysics Data System (ADS)

    Picard, Frédéric; Wanatabe, Mitsuhiro; Schoonjans, Kristina; Lydon, John; O'Malley, Bert W.; Auwerx, Johan

    2002-11-01

    Gestational diabetes coincides with elevated circulating progesterone levels. We show that progesterone accelerates the progression of diabetes in female db/db mice. In contrast, RU486, an antagonist of the progesterone receptor (PR), reduces blood glucose levels in both female WT and db/db mice. Furthermore, female, but not male, PR-/- mice had lower fasting glycemia than PR+/+ mice and showed higher insulin levels on glucose injection. Pancreatic islets from female PR-/- mice were larger and secreted more insulin consequent to an increase in -cell mass due to an increase in -cell proliferation. These findings demonstrate an important role of progesterone signaling in insulin release and pancreatic function and suggest that it affects the susceptibility to diabetes.

  13. Small heterodimer partner overexpression partially protects against liver tumor development in farnesoid X receptor knockout mice

    SciTech Connect

    Li, Guodong; Kong, Bo; Zhu, Yan; Zhan, Le; Williams, Jessica A.; Tawfik, Ossama; Kassel, Karen M.; Luyendyk, James P.; Wang, Li; Guo, Grace L.

    2013-10-15

    Farnesoid X receptor (FXR, Nr1h4) and small heterodimer partner (SHP, Nr0b2) are nuclear receptors that are critical to liver homeostasis. Induction of SHP serves as a major mechanism of FXR in suppressing gene expression. Both FXR{sup −/−} and SHP{sup −/−} mice develop spontaneous hepatocellular carcinoma (HCC). SHP is one of the most strongly induced genes by FXR in the liver and is a tumor suppressor, therefore, we hypothesized that deficiency of SHP contributes to HCC development in the livers of FXR{sup −/−} mice and therefore, increased SHP expression in FXR{sup −/−} mice reduces liver tumorigenesis. To test this hypothesis, we generated FXR{sup −/−} mice with overexpression of SHP in hepatocytes (FXR{sup −/−}/SHP{sup Tg}) and determined the contribution of SHP in HCC development in FXR{sup −/−} mice. Hepatocyte-specific SHP overexpression did not affect liver tumor incidence or size in FXR{sup −/−} mice. However, SHP overexpression led to a lower grade of dysplasia, reduced indicator cell proliferation and increased apoptosis. All tumor-bearing mice had increased serum bile acid levels and IL-6 levels, which was associated with activation of hepatic STAT3. In conclusion, SHP partially protects FXR{sup −/−} mice from HCC formation by reducing tumor malignancy. However, disrupted bile acid homeostasis by FXR deficiency leads to inflammation and injury, which ultimately results in uncontrolled cell proliferation and tumorigenesis in the liver. - Highlights: • SHP does not prevent HCC incidence nor size in FXR KO mice but reduces malignancy. • Increased SHP promotes apoptosis. • Bile acids and inflammation maybe critical for HCC formation with FXR deficiency.

  14. Vasopressin 1b receptor knock-out impairs memory for temporal order.

    PubMed

    DeVito, Loren M; Konigsberg, Rachael; Lykken, Christine; Sauvage, Magdalena; Young, W Scott; Eichenbaum, Howard

    2009-03-01

    Mice lacking a functional vasopressin 1b receptor (Avpr1b) display decreased levels of aggression and social memory. Here, we used Avpr1b-knock-out (Avpr1b(-/-)) mice to examine whether an abnormality of this receptor results in specific cognitive deficits in the domain of hippocampal function. Avpr1b(-/-) mice were deficient in sociability and in detecting social novelty, extending previous findings of impairment in social recognition in these mutants. Avpr1b(-/-) mice could recognize previously explored objects and remember where they were experienced, but they were impaired in remembering the temporal order of presentation of those objects. Consistent with this finding, Avpr1b(-/-) mice were also impaired on an object-odor paired associate task that involved a temporal discontiguity between the associated elements. Finally, Avpr1b(-/-) mice performed normally in learning a set of overlapping odor discriminations and could infer relationships among odors that were only indirectly associated (i.e., transitive inference), indicating intact relational memory. The Avpr1b is expressed at much higher levels than any other part of the brain in the pyramidal cells of hippocampal CA2 area, a subfield of the hippocampus that has physiological and genetic properties that distinguish it from subfields CA1 and CA3. The combined results suggest that the Avpr1b, perhaps in CA2, may play a highly specific role in social behavior and episodic memory. Because schizophrenia and bipolar disorder are associated with a unique pathology in CA2 and impairments in both social behavior and episodic memory, this animal model could provide insights into the etiology of these disorders.

  15. Knockout of the aryl hydrocarbon receptor results in distinct hepatic and renal phenotypes in rats and mice

    SciTech Connect

    Harrill, Joshua A.; Hukkanen, Renee R.; Lawson, Marie; Martin, Greg; Gilger, Brian; Soldatow, Valerie; LeCluyse, Edward L.; Budinsky, Robert A.; Rowlands, J. Craig; Thomas, Russell S.

    2013-10-15

    The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor which plays a role in the development of multiple tissues and is activated by a large number of ligands, including 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). In order to examine the roles of the AHR in both normal biological development and response to environmental chemicals, an AHR knockout (AHR-KO) rat model was created and compared with an existing AHR-KO mouse. AHR-KO rats harboring either 2-bp or 29-bp deletion mutation in exon 2 of the AHR were created on the Sprague–Dawley genetic background using zinc-finger nuclease (ZFN) technology. Rats harboring either mutation type lacked expression of AHR protein in the liver. AHR-KO rats were also insensitive to thymic involution, increased hepatic weight and the induction of AHR-responsive genes (Cyp1a1, Cyp1a2, Cyp1b1, Ahrr) following acute exposure to 25 μg/kg TCDD. AHR-KO rats had lower basal expression of transcripts for these genes and also accumulated ∼ 30–45-fold less TCDD in the liver at 7 days post-exposure. In untreated animals, AHR-KO mice, but not AHR-KO rats, had alterations in serum analytes indicative of compromised hepatic function, patent ductus venosus of the liver and persistent hyaloid arteries in the eye. AHR-KO rats, but not AHR-KO mice, displayed pathological alterations to the urinary tract: bilateral renal dilation (hydronephrosis), secondary medullary tubular and uroepithelial degenerative changes and bilateral ureter dilation (hydroureter). The present data indicate that the AHR may play significantly different roles in tissue development and homeostasis and toxicity across rodent species. - Highlights: • An AHR knockout rat was generated on a Sprague–Dawley outbred background. • AHR-KO rats lack expression of AHR protein. • AHR-KO rats are insensitive to TCDD-mediated effects. • Data suggests difference in the role of AHR in tissue development of rats and mice. • Abnormalities in vascular

  16. Ovariectomy-mediated impairment of spatial working memory, but not reference memory, is attenuated by the knockout of the dopamine D(3) receptor in female mice.

    PubMed

    Cao, Fang; Zhang, Hongbo; Meng, Xia; Feng, Jiali; Li, Teng; Wei, Shuguang; Li, Shengbin

    2013-06-15

    Memory modulation is implemented through many different factors, such as the dopaminergic system and ovarian hormones. Alterations of these factors may cause memory behavior changes. In the current study, dopamine D3 receptor mutant (D3(-/-)) female mice and their wild-type (WT) controls were used and randomly assigned to ovariectomized (OVX) and sham-operated (Sham) groups (four groups: WT-OVX, WT-Sham, D3(-/-)-OVX, and D3(-/-)-Sham). The possibility of co-effects of the dopamine D3 receptor and ovarian hormones on cognitive behavior was then examined. The spatial reference memory (SRM) and the motivation to escape from the water maze were not affected by either knockout of the dopamine D3 receptor or ovariectomy. Knockout of the dopamine D3 receptor had no effect on spatial working memory (SWM) in the Sham groups, but had a positive effect on SWM in the OVX groups. While an ovariectomy inhibited SWM in WT mice, it had no effect on SWM in D3(-/-) mice. These data suggested that ovarian hormone deprivation may induce spatial working memory decline, and blockade of D3 receptors could ameliorate this impairment. Based on our findings, there may be specific molecular changes responsible for the function of D3 receptors in modulating information processes under conditions of ovarian hormone deficit, which need to be further elucidated.

  17. Development of schemas revealed by prior experience and NMDA receptor knock-out

    PubMed Central

    Dragoi, George; Tonegawa, Susumu

    2013-01-01

    Prior experience accelerates acquisition of novel, related information through processes like assimilation into mental schemas, but the underlying neuronal mechanisms are poorly understood. We investigated the roles that prior experience and hippocampal CA3 N-Methyl-D-aspartate receptor (NMDAR)-dependent synaptic plasticity play in CA1 place cell sequence encoding and learning during novel spatial experiences. We found that specific representations of de novo experiences on linear environments were formed on a framework of pre configured network activity expressed in the preceding sleep and were rapidly, flexibly adjusted via NMDAR-dependent activity. This prior experience accelerated encoding of subsequent experiences on contiguous or isolated novel tracks, significantly decreasing their NMDAR-dependence. Similarly, de novo learning of an alternation task was facilitated by CA3 NMDARs; this experience accelerated subsequent learning of related tasks, independent of CA3 NMDARs, consistent with a schema-based learning. These results reveal the existence of distinct neuronal encoding schemes which could explain why hippocampal dysfunction results in anterograde amnesia while sparing recollection of old, schema-based memories. DOI: http://dx.doi.org/10.7554/eLife.01326.001 PMID:24327561

  18. Altered enteroendocrine cell expression in T cell receptor alpha chain knock-out mice.

    PubMed

    Rubin, D C; Zhang, H; Qian, P; Lorenz, R G; Hutton, K; Peters, M G

    2000-10-15

    Mice lacking T cell receptor alpha chain (TCRalpha(-/-)) develop inflammation of the colon. We have examined the effect of this inflammation on the colonic epithelium by studying markers of epithelial cuff, enteroendocrine, and immune cell differentiation. Using immunohistochemical techniques, colons were compared in normal C57/BL6 and murine TCR alpha(-/-) mice aged 2 and 3 weeks and 3-11 months. TCR alpha(-/-) mice aged 3-11 months had histologic evidence of inflammation with increased expression of CD45, CD4+, CD8+, and B220+ cells and a decrease in expression of IgA+ cells. There was a decrease in the number of cholecystokinin, serotonin, and neurotensin enteroendocrine expressing cells in the colon of TCR alpha(-/-) mice. These changes were not present in 2-3-week-old suckling/weaning mice. In contrast, peptide tyrosine tyrosine (PYY), glucagon-like peptide-1, and gastrin expression did not change and small intestinal enteroendocrine cells remained unaltered. The change in colonic enteroendocrine cell expression appears to be a specific response, since only a subset of these cells was altered, and the epithelium was intact by histologic analysis. The absence of functional T cells in TCR alpha(-/-) colon has a marked effect on differentiation of a specific subpopulation of enteroendocrine cells, prior to loss of integrity of the epithelium. PMID:11054861

  19. Activation of the serotonin 1A receptor alters the temporal characteristics of auditory responses in the inferior colliculus.

    PubMed

    Hurley, Laura M

    2007-11-21

    Serotonin, like other neuromodulators, acts on a range of receptor types, but its effects also depend on the functional characteristics of the neurons responding to receptor activation. In the inferior colliculus (IC), an auditory midbrain nucleus, activation of a common serotonin (5-HT) receptor type, the 5-HT 1A receptor, depresses auditory-evoked responses in many neurons. Whether these effects occur differentially in different types of neurons is unknown. In the current study, the effects of iontophoretic application of the 5-HT 1A agonist 8-OH-DPAT on auditory responses were compared with the characteristic frequencies (CFs), recording depths, and control first-spike latencies of the same group of IC neurons. The 8-OH-DPAT-evoked change in response significantly correlated with first-spike latency across the population, so that response depressions were more prevalent in longer-latency neurons. The 8-OH-DPAT-evoked change in response did not correlate with CF or with recording depth. 8-OH-DPAT also altered the temporal characteristics of spike trains in a subset of neurons that fired multiple spikes in response to brief stimuli. For these neurons, activation of the 5-HT 1A receptor suppressed lagging spikes proportionally more than initial spikes. These results suggest that the 5-HT 1A receptor, by affecting the timing of the responses of both individual neurons and the neuron population, shifts the temporal profile of evoked activity within the IC. PMID:17916336

  20. Serotonin directly stimulates luteinizing hormone-releasing hormone release from GT1 cells via 5-HT7 receptors.

    PubMed

    Héry, M; François-Bellan, A M; Héry, F; Deprez, P; Becquet, D

    1997-10-01

    Luteinizing hormone-releasing hormone (LHRH release, which serves as the primary drive to the hypothalamic-pituitary gonadal axis, is controlled by many neuromediators. Serotonin has been implicated in this regulation. However, it is unclear whether the central effect of serotonin on LHRH secretion is exerted directly on LHRH neurosecretory neurons or indirectly via multisynaptic pathways. The present studies were undertaken in order to examine whether LHRH secretion from immortalized LHRH cell lines is directly regulated by serotonin and, if so, to identify the receptor subtype involved. 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT), a 5-HT1A/7 receptor agonist, stimulated LHRH release from GT1-1 cells. This effect was blocked by ritanserin, a 5-HT2/7 receptor antagonist, but not by SDZ-216-525, a 5-HT1A antagonist. Basal LHRH release was not affected by the 5-HT2 agonist DOI. Reverse transcription and polymerase chain reaction technique (RT-PCR) was used in order to identify 5-HT1A and 5-HT7 receptor mRNA in immortalized LHRH cell lines. GT1-1 cells express mRNA for the 5-HT7, but not the 5-HT1A receptor subtypes. These results demonstrate a direct stimulatory effect of serotonin on LHRH release via 5-HT7 receptor.

  1. 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.

  2. Activation of the serotonin 1A receptor alters the temporal characteristics of auditory responses in the inferior colliculus

    PubMed Central

    Hurley, Laura M.

    2008-01-01

    Serotonin, like other neuromodulators, acts on a range of receptor types, but its effects also depend on the functional characteristics of the neurons responding to receptor activation. In the inferior colliculus (IC), an auditory midbrain nucleus, activation of a common serotonin (5-HT) receptor type, the 5-HT1A receptor, depresses auditory-evoked responses in many neurons. Whether these effects occur differentially in different types of neurons is unknown. In the current study, the effects of iontophoretic application of the 5-HT1A agonist 8-OH-DPAT on auditory responses were compared with the characteristic frequencies (CFs), recording depths, and control first-spike latencies of the same group of IC neurons. The 8-OH-DPAT-evoked change in response significantly correlated with first-spike latency across the population, so that response depressions were more prevalent in longer-latency neurons. The 8-OH-DPAT-evoked change in response did not correlate with CF or with recording depth. 8-OH-DPAT also altered the temporal characteristics of spike trains in a subset of neurons that fired multiple spikes in response to brief stimuli. For these neurons, activation of the 5-HT1A receptor suppressed lagging spikes proportionally more than initial spikes. These results suggest that the 5-HT1A receptor, by affecting the timing of the responses of both individual neurons and the neuron population, shifts the temporal profile of evoked activity within the IC. PMID:17916336

  3. Endothelium dysfunction in LDL receptor knockout mice: a role for H2O2

    PubMed Central

    Rabelo, Luíza A; Cortes, Steyner F; Alvarez-Leite, Jacqueline I; Lemos, Virgínia S

    2003-01-01

    In this study, the role of endogenous H2O2 as an endothelium-dependent relaxant factor was characterised in aortas from C57BL/6J and LDL receptor-deficient mice (LDLR−/−). Aortic rings from LDLR−/− mice showed impaired endothelium-dependent relaxation to acetylcholine (ACh; 0.001–100 μM) and to the Ca2+ ionophore A23187 (0.001–3 μM) compared with aortic rings from control mice. Endothelium-independent relaxation produced by the NO donor, 3-morpholino-sydnonimine (SIN-1) was not different between strains. Pretreatment of vessels with L-NNA (100 μM) or L-NNA (100 μM) plus L-NAME (300 μM) plus haemoglobin (10 μM) markedly decreased, but did not abolish the relaxation to ACh in control mice. In the aortas from LDLR−/− mice treated with L-NNA (100 μM), ACh induced a contractile effect. Catalase (800 and 2400 U ml−1) shifted to the right the endothelium-dependent relaxation to ACh in aortas from control but not from LDLR−/− mice. Aminotriazole (50 mM), which inhibits catalase, abolished its effect on control mice. Treatment of vessels with L-NNA and catalase abolished vasorelaxation induced by ACh. Indomethacin (10 μM) did not modify the concentration–response curve to ACh. Superoxide dismutase (300 U ml−1) did not change ACh-induced relaxation in both strains. Exogenous H2O2 produced a concentration-dependent relaxation in endothelium-denuded aortic rings, which was not different between strains. It is concluded that H2O2 greatly contributes to relaxation to ACh in aorta from control mice. Endothelial-dependent relaxation to ACh is impaired in LDLR−/− mice. Reduced biosynthesis or increased inactivation of H2O2 is the possible mechanism responsible for endothelial dysfunction in aortas of atherosclerosis-susceptible LDLR−/− mice. PMID:12711621

  4. Aryl hydrocarbon receptor knock-out exacerbates choroidal neovascularization via multiple pathogenic pathways.

    PubMed

    Choudhary, Mayur; Kazmin, Dmitri; Hu, Peng; Thomas, Russell S; McDonnell, Donald P; Malek, Goldis

    2015-01-01

    The aryl hydrocarbon receptor (AhR) is a heterodimeric transcriptional regulator with pleiotropic functions in xenobiotic metabolism and detoxification, vascular development and cancer. Herein, we report a previously undescribed role for the AhR signalling pathway in the pathogenesis of the wet, neovascular subtype of age-related macular degeneration (AMD), the leading cause of vision loss in the elderly in the Western world. Comparative analysis of gene expression profiles of aged AhR(-/-) and wild-type (wt) mice, using high-throughput RNA sequencing, revealed differential modulation of genes belonging to several AMD-related pathogenic pathways, including inflammation, angiogenesis and extracellular matrix regulation. To investigate AhR regulation of these pathways in wet AMD, we experimentally induced choroidal neovascular lesions in AhR(-/-) mice and found that they measured significantly larger in area and volume compared to age-matched wt mice. Furthermore, these lesions displayed a higher number of ionized calcium-binding adaptor molecule 1-positive (Iba1(+) ) microglial cells and a greater amount of collagen type IV deposition, events also seen in human wet AMD pathology specimens. Consistent with our in vivo observations, AhR knock-down was sufficient to increase choroidal endothelial cell migration and tube formation in vitro. Moreover, AhR knock-down caused an increase in collagen type IV production and secretion in both retinal pigment epithelial (RPE) and choroidal endothelial cell cultures, increased expression of angiogenic and inflammatory molecules, including vascular endothelial growth factor A (VEGFA) and chemokine (C-C motif) ligand 2 (CCL2) in RPE cells, and increased expression of secreted phosphoprotein 1 (SPP1) and transforming growth factor-β1 (TGFβ1) in choroidal endothelial cells. Collectively, our findings identify AhR as a regulator of multiple pathogenic pathways in experimentally induced choroidal neovascularization, findings that

  5. Aryl hydrocarbon receptor knock-out exacerbates choroidal neovascularization via multiple pathogenic pathways

    PubMed Central

    Choudhary, Mayur; Kazmin, Dmitri; Hu, Peng; Thomas, Russell S; McDonnell, Donald P; Malek, Goldis

    2015-01-01

    The aryl hydrocarbon receptor (AhR) is a heterodimeric transcriptional regulator with pleiotropic functions in xenobiotic metabolism and detoxification, vascular development and cancer. Herein, we report a previously undescribed role for the AhR signalling pathway in the pathogenesis of the wet, neovascular subtype of age-related macular degeneration (AMD), the leading cause of vision loss in the elderly in the Western world. Comparative analysis of gene expression profiles of aged AhR−/− and wild-type (wt) mice, using high-throughput RNA sequencing, revealed differential modulation of genes belonging to several AMD-related pathogenic pathways, including inflammation, angiogenesis and extracellular matrix regulation. To investigate AhR regulation of these pathways in wet AMD, we experimentally induced choroidal neovascular lesions in AhR−/− mice and found that they measured significantly larger in area and volume compared to age-matched wt mice. Furthermore, these lesions displayed a higher number of ionized calcium-binding adaptor molecule 1-positive (Iba1+) microglial cells and a greater amount of collagen type IV deposition, events also seen in human wet AMD pathology specimens. Consistent with our in vivo observations, AhR knock-down was sufficient to increase choroidal endothelial cell migration and tube formation in vitro. Moreover, AhR knock-down caused an increase in collagen type IV production and secretion in both retinal pigment epithelial (RPE) and choroidal endothelial cell cultures, increased expression of angiogenic and inflammatory molecules, including vascular endothelial growth factor A (VEGFA) and chemokine (C–C motif) ligand 2 (CCL2) in RPE cells, and increased expression of secreted phosphoprotein 1 (SPP1) and transforming growth factor-β1 (TGFβ1) in choroidal endothelial cells. Collectively, our findings identify AhR as a regulator of multiple pathogenic pathways in experimentally induced choroidal neovascularization, findings that

  6. Serotonin1A receptors in the pathophysiology of schizophrenia: development of novel cognition-enhancing therapeutics.

    PubMed

    Sumiyoshi, Tomiki; Bubenikova-Valesova, Vera; Horacek, Jiri; Bert, Bettina

    2008-10-01

    Serotonin (5-HT) receptors have been suggested to play key roles in psychosis, cognition, and mood via influence on neurotransmitters, synaptic integrity, and neural plasticity. Specifically, genetic evidence indicates that 5-HT(1A), 5-HT(2A), and 5-HT(2C) receptor single-nucleotide polymorphisms (SNPs) are related to psychotic symptoms, cognitive disturbances, and treatment response in schizophrenia. Data from animal research suggest the role of 5-HT in cognition via its influence on dopaminergic, cholinergic, glutamatergic, and GABAergic function. This article provides up-to-date findings on the role of 5-HT receptors in endophenotypic variations in schizophrenia and the development of newer cognition-enhancing medications, based on basic science and clinical evidence. Imaging genetics studies on associations of polymorphisms of several 5-HT receptor subtypes with brain structure, function, and metabolism suggest a role for the prefrontal cortex and the parahippocampal gyrus in cognitive impairments of schizophrenia. Data from animal experiments to determine the effect of agonists/antagonists at 5-HT(1A), 5-HT(2A), and 5-HT(2C) receptors on behavioral performance in animal models of schizophrenia based on the glutamatergic hypothesis provide useful information. For this purpose, standard as well as novel cognitive tasks provide a measure of memory/information processing and social interaction. In order to scrutinize mixed evidence for the ability of 5-HT(1A) agonists/antagonists to improve cognition, behavioral data in various paradigms from transgenic mice overexpressing 5-HT(1A) receptors provide valuable insights. Clinical trials reporting the advantage of 5-HT(1A) partial agonists add to efforts to shape pharmacologic perspectives concerning cognitive enhancement in schizophrenia by developing novel compounds acting on 5-HT receptors. Overall, these lines of evidence from translational research will facilitate the development of newer pharmacologic strategies

  7. Impact of growth hormone resistance on female reproductive function: new insights from growth hormone receptor knockout mice.

    PubMed

    Zaczek, Denise; Hammond, James; Suen, Lii; Wandji, Serge; Service, Darlene; Bartke, Andrzej; Chandrashekar, Varadaraj; Coschigano, Karen; Kopchick, John

    2002-10-01

    We examined multiple aspects of reproductive function in growth hormone receptor gene knockout (GHR-KO) and normal mice to clarify the role of growth hormone in female reproduction. In adult animals, estrous cycle duration was comparable in all mice housed individually but was significantly longer in group-housed GHR-KO females. Histological evaluation of ovaries of adult females at estrus showed that the numbers of preovulatory follicles and corpora lutea were significantly reduced in GHR-KO mice, as was the plasma estradiol level. The number of atretic preovulatory follicles was reduced in GHR gene-ablated animals. Although reverse transcription polymerase chain reaction analysis revealed reduced ovarian insulin-like growth factor I (IGF-I) mRNA expression in GHR-KO females, the expression of several steroidogenic enzyme mRNAs did not differ between groups. The numbers of active corpora lutea and uterine implantation sites were reduced in GHR-KO females at Day 7 of gestation. When young females were mated to normal males, latency to first mating and age of the female at first mating were significantly delayed in GHR-KO females, but maternal age at first conception was similar between groups. Significantly fewer virgin GHR-KO females exhibited pseudopregnancies when initially placed with vasectomized normal males than did normal female counterparts. Growth hormone resistance and IGF-I insufficiency negatively impacted 1) follicular development/ovulation rate, 2) sexual maturation, 3) production of and responsiveness to pheromonal signals, and 4) the ability of virgin females to respond to coitus by activation of luteal function. Although GHR-KO female mice are fertile, they exhibit quantitative deficits in various parameters of reproductive function.

  8. Knockout of NMDA-receptors from parvalbumin interneurons sensitizes to schizophrenia-related deficits induced by MK-801

    PubMed Central

    Bygrave, A M; Masiulis, S; Nicholson, E; Berkemann, M; Barkus, C; Sprengel, R; Harrison, P J; Kullmann, D M; Bannerman, D M; Kätzel, D

    2016-01-01

    It has been suggested that a functional deficit in NMDA-receptors (NMDARs) on parvalbumin (PV)-positive interneurons (PV-NMDARs) is central to the pathophysiology of schizophrenia. Supportive evidence come from examination of genetically modified mice where the obligatory NMDAR-subunit GluN1 (also known as NR1) has been deleted from PV interneurons by Cre-mediated knockout of the corresponding gene Grin1 (Grin1ΔPV mice). Notably, such PV-specific GluN1 ablation has been reported to blunt the induction of hyperlocomotion (a surrogate for psychosis) by pharmacological NMDAR blockade with the non-competitive antagonist MK-801. This suggests PV-NMDARs as the site of the psychosis-inducing action of MK-801. In contrast to this hypothesis, we show here that Grin1ΔPV mice are not protected against the effects of MK-801, but are in fact sensitized to many of them. Compared with control animals, Grin1ΔPVmice injected with MK-801 show increased stereotypy and pronounced catalepsy, which confound the locomotor readout. Furthermore, in Grin1ΔPVmice, MK-801 induced medial-prefrontal delta (4 Hz) oscillations, and impaired performance on tests of motor coordination, working memory and sucrose preference, even at lower doses than in wild-type controls. We also found that untreated Grin1ΔPVmice are largely normal across a wide range of cognitive functions, including attention, cognitive flexibility and various forms of short-term memory. Taken together these results argue against PV-specific NMDAR hypofunction as a key starting point of schizophrenia pathophysiology, but support a model where NMDAR hypofunction in multiple cell types contribute to the disease. PMID:27070406

  9. Knockout of the aryl hydrocarbon receptor results in distinct hepatic and renal phenotypes in rats and mice.

    PubMed

    Harrill, Joshua A; Hukkanen, Renee R; Lawson, Marie; Martin, Greg; Gilger, Brian; Soldatow, Valerie; Lecluyse, Edward L; Budinsky, Robert A; Rowlands, J Craig; Thomas, Russell S

    2013-10-15

    The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor which plays a role in the development of multiple tissues and is activated by a large number of ligands, including 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). In order to examine the roles of the AHR in both normal biological development and response to environmental chemicals, an AHR knockout (AHR-KO) rat model was created and compared with an existing AHR-KO mouse. AHR-KO rats harboring either 2-bp or 29-bp deletion mutation in exon 2 of the AHR were created on the Sprague-Dawley genetic background using zinc-finger nuclease (ZFN) technology. Rats harboring either mutation type lacked expression of AHR protein in the liver. AHR-KO rats were also insensitive to thymic involution, increased hepatic weight and the induction of AHR-responsive genes (Cyp1a1, Cyp1a2, Cyp1b1, Ahrr) following acute exposure to 25 μg/kg TCDD. AHR-KO rats had lower basal expression of transcripts for these genes and also accumulated ~30-45-fold less TCDD in the liver at 7 days post-exposure. In untreated animals, AHR-KO mice, but not AHR-KO rats, had alterations in serum analytes indicative of compromised hepatic function, patent ductus venosus of the liver and persistent hyaloid arteries in the eye. AHR-KO rats, but not AHR-KO mice, displayed pathological alterations to the urinary tract: bilateral renal dilation (hydronephrosis), secondary medullary tubular and uroepithelial degenerative changes and bilateral ureter dilation (hydroureter). The present data indicate that the AHR may play significantly different roles in tissue development and homeostasis and toxicity across rodent species. PMID:23859880

  10. Yellow wine polyphenolic compounds inhibit matrix metalloproteinase-2, -9 expression and improve atherosclerotic plaque in LDL-receptor-knockout mice.

    PubMed

    Zhai, Xiaoya; Chi, Jufang; Tang, Weiliang; Ji, Zheng; Zhao, Fei; Jiang, Chengjian; Lv, Haitao; Guo, Hangyuan

    2014-01-01

    Many epidemiological studies have strongly suggested an inverse correlation between dietary polyphenol consumption and reduced risks of cardiovascular diseases. Yellow rice wine is a Chinese specialty and one of the three most ancient wines in the world (Shaoxing rice wine, beer, and grape wine). There is a large amount of polyphenol substances in yellow rice wine. This experiment was designed to study the potential beneficial effects of yellow wine polyphenolic compounds (YWPC) from yellow rice wine on progression of atherosclerosis in vivo and to further explore its underlying mechanisms. Six-week-old male LDL-receptor-knockout mice were treated with high-fat diet to establish the mouse model with atherosclerosis. Animals received 10, 30, or 50 mg/kg per day of YWPC or 10 mg/kg per day rosuvastatin or water (vehicle) for 14 weeks. The results indicated that YWPC and rosuvastatin significantly decreased circulating total cholesterol and low-density lipoprotein cholesterol. Compared to the control group, the atherosclerosis lesion area in the rosuvastatin-intervention group and YWPC at doses of 10, 30, and 50 mg/kg per day intervention groups decreased by 74.14%, 18.51%, 40.09%, and 38.42%, respectively. YWPC and rosuvastatin decreased the expression and activity of matrix metalloproteinases (MMP)-2, 9, whereas the expression of the endogenous inhibitors of these proteins, namely, tissue inhibitors of matrix metalloproteinases (TIMP)-1, 2, increased when compared to the control group. It can be concluded that the YWPC is similar to the benefic effects of rosuvastatin on cardiovascular system. These effects may be attributed to their anti-atherosclerotic actions by lowering lipid and modulating the activity and expression of MMP-2, 9 and TIMP-1, 2.

  11. Toll-like receptor 4 knockout ameliorates neuroinflammation due to lung-brain interaction in mechanically ventilated mice.

    PubMed

    Chen, Ting; Chen, Chang; Zhang, Zongze; Zou, Yufeng; Peng, Mian; Wang, Yanlin

    2016-08-01

    Toll-like receptor 4 (TLR4) is a crucial receptor in the innate immune system, and increasing evidence supports its role in inflammation, stress, and tissue injury, including injury to the lung and brain. We aimed to investigate the effects of TLR4 on neuroinflammation due to the lung-brain interaction in mechanically ventilated mice. Male wild-type (WT) C57BL/6 and TLR4 knockout (TLR4 KO) mice were divided into three groups: (1) control group (C): spontaneous breathing; (2) anesthesia group (A): spontaneous breathing under anesthesia; and (3) mechanical ventilation group (MV): 6h of MV under anesthesia. The behavioral responses of mice were tested with fear conditioning tests. The histological changes in the lung and brain were assessed using hematoxylin-eosin (HE) staining. The level of TLR4 mRNA in tissue was measured using reverse transcription-polymerase chain reaction (RT-PCR). The levels of inflammatory cytokines were measured with an enzyme-linked immunosorbent assay (ELISA). Microgliosis, astrocytosis, and the TLR4 immunoreactivity in the hippocampus were measured by double immunofluorescence. MV mice exhibited impaired cognition, and this impairment was less severe in TLR4 KO mice than in WT mice. In WT mice, MV increased TLR4 mRNA expression in the lung and brain. MV induced mild lung injury, which was prevented in TLR4 KO mice. MV mice exhibited increased levels of inflammatory cytokines, increased microglia and astrocyte activation. Microgliosis was alleviated in TLR4 KO mice. MV mice exhibited increased TLR4 immunoreactivity, which was expressed in microglia and astrocytes. These results demonstrate that TLR4 is involved in neuroinflammation due to the lung-brain interaction and that TLR4 KO ameliorates neuroinflammation due to lung-brain interaction after prolonged MV. In addition, Administration of a TLR4 antagonist (100μg/mice) to WT mice also significantly attenuated neuroinflammation of lung-brain interaction due to prolonged MV. TLR4 antagonism

  12. Serum cholesterol and expression of ApoAI, LXRbeta and SREBP2 in vitamin D receptor knock-out mice.

    PubMed

    Wang, Jing-Huan; Keisala, Tiina; Solakivi, Tiina; Minasyan, Anna; Kalueff, Allan V; Tuohimaa, Pentti

    2009-02-01

    Vitamin D insufficiency has been reported to be associated with increased blood cholesterol concentrations. Here we used two strains of VDR knock-out (VDR-KO) mice to study whether a lack of vitamin D action has any effect on cholesterol metabolism. In 129S1 mice, both in male and female VDR-KO mice serum total cholesterol levels were significantly higher than those in wild type (WT) mice (20.7% (P=0.05) and 22.2% (P=0.03), respectively). In addition, the serum high-density lipoprotein-bound cholesterol (HDL-C) level was 22% (P=0.03), respectively higher in male VDR-KO mice than in WT mice. The mRNA expression levels of five cholesterol metabolism related genes in livers of 129S1 mice were studied using quantitative real-time PCR (QRT-PCR): ATP-binding cassette transporter A1 (ABCA1), regulatory element binding protein (SREBP2), apolipoprotein A-I (ApoAI), low-density lipoprotein receptor (LDLR) and liver X receptor beta (LXRbeta). In the mutant male mice, the mRNA level of ApoAI and LXRbeta were 49.2% (P=0.005) and 38.8% (P=0.034) higher than in the WT mice. These changes were not observed in mutant female mice, but the female mutant mice showed 52.5% (P=0.006) decrease of SREBP2 mRNA expression compared to WT mice. Because the mutant mice were fed with a special rescue diet, we wanted to test whether the increased cholesterol levels in mutant mice were due to the diet. Both the WT and mutant NMRI mice were given the same diet for 3 weeks before the blood sampling. No difference in cholesterol or in HDL-C between WT and mutant mice was found. The results suggest that the food, gender and genetic background have an effect on the cholesterol metabolism. Although VDR seems to regulate some of the genes involved in cholesterol metabolism, its role in the regulation of serum cholesterol seems to be minimal.

  13. Differential regulation of primary afferent input to spinal cord by muscarinic receptor subtypes delineated using knockout mice.

    PubMed

    Chen, Shao-Rui; Chen, Hong; Yuan, Wei-Xiu; Wess, Jürgen; Pan, Hui-Lin

    2014-05-16

    Stimulation of muscarinic acetylcholine receptors (mAChRs) inhibits nociceptive transmission at the spinal level. However, it is unclear how each mAChR subtype regulates excitatory synaptic input from primary afferents. Here we examined excitatory postsynaptic currents (EPSCs) of dorsal horn neurons evoked by dorsal root stimulation in spinal cord slices from wild-type and mAChR subtype knock-out (KO) mice. In wild-type mice, mAChR activation with oxotremorine-M decreased the amplitude of monosynaptic EPSCs in ∼67% of neurons but increased it in ∼10% of neurons. The inhibitory effect of oxotremorine-M was attenuated by the M2/M4 antagonist himbacine in the majority of neurons, and the remaining inhibition was abolished by group II/III metabotropic glutamate receptor (mGluR) antagonists in wild-type mice. In M2/M4 double-KO mice, oxotremorine-M inhibited monosynaptic EPSCs in significantly fewer neurons (∼26%) and increased EPSCs in significantly more neurons (33%) compared with wild-type mice. Blocking group II/III mGluRs eliminated the inhibitory effect of oxotremorine-M in M2/M4 double-KO mice. In M2 single-KO and M4 single-KO mice, himbacine still significantly reduced the inhibitory effect of oxotremorine-M. However, the inhibitory and potentiating effects of oxotremorine-M on EPSCs in M3 single-KO and M1/M3 double-KO mice were similar to those in wild-type mice. In M5 single-KO mice, oxotremorine-M failed to potentiate evoked EPSCs, and its inhibitory effect was abolished by himbacine. These findings indicate that activation of presynaptic M2 and M4 subtypes reduces glutamate release from primary afferents. Activation of the M5 subtype either directly increases primary afferent input or inhibits it through indirectly stimulating group II/III mGluRs. PMID:24695732

  14. Mast cell expression of the serotonin1A receptor in guinea pig and human intestine.

    PubMed

    Wang, Guo-Du; Wang, Xi-Yu; Zou, Fei; Qu, Meihua; Liu, Sumei; Fei, Guijun; Xia, Yun; Needleman, Bradley J; Mikami, Dean J; Wood, Jackie D

    2013-05-15

    Serotonin [5-hydroxytryptamine (5-HT)] is released from enterochromaffin cells in the mucosa of the small intestine. We tested a hypothesis that elevation of 5-HT in the environment of enteric mast cells might degranulate the mast cells and release mediators that become paracrine signals to the enteric nervous system, spinal afferents, and secretory glands. Western blotting, immunofluorescence, ELISA, and pharmacological analysis were used to study expression of 5-HT receptors by mast cells in the small intestine and action of 5-HT to degranulate the mast cells and release histamine in guinea pig small intestine and segments of human jejunum discarded during Roux-en-Y gastric bypass surgeries. Mast cells in human and guinea pig preparations expressed the 5-HT1A receptor. ELISA detected spontaneous release of histamine in guinea pig and human preparations. The selective 5-HT1A receptor agonist 8-hydroxy