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Sample records for dopamine depletion induces

  1. Effects of dopamine depletion in the medial prefrontal cortex on the stress-induced increase in extracellular dopamine in the nucleus accumbens core and shell.

    PubMed

    King, D; Zigmond, M J; Finlay, J M

    1997-03-01

    In the present study we examined whether depletion of dopamine in the medial prefrontal cortex alters the neurochemical activity of mesoaccumbens dopamine neurons and/or their behavioral correlate, motor behavior. Infusion of 6-hydroxydopamine (1 microgram) into the medial prefrontal cortex of rats pretreated with a norepinephrine uptake blocker produced a 70% loss of tissue dopamine, with relative sparing of the norepinephrine content (-23%) in that region. Using in vivo microdialysis, we monitored basal and evoked extracellular dopamine in the nucleus accumbens core and shell of control and lesioned rats. The concentration of basal extracellular dopamine in the nucleus accumbens core was similar in control and lesioned rats; however, basal dopamine efflux in the nucleus accumbens shell was approximately 30% higher in lesioned rats than in controls. Lesions did not alter the ability of systemic D-amphetamine (1.5 mg/kg, i.p.) to increase extracellular dopamine in the nucleus accumbens shell, in contrast, the dopamine depletion in the medial prefrontal cortex attenuated the amphetamine-induced increase in extracellular dopamine in the nucleus accumbens core, as well as the amphetamine-induced increase in locomotor activity. Lesions did not significantly alter the effects of tail pressure (30 min) on extracellular dopamine in the nucleus accumbens core. However, the depletion of dopamine in the medial prefrontal cortex potentiated the stress-induced increase in extracellular dopamine in the nucleus accumbens shell. These data demonstrate that mesocortical dopamine neurons influence (i) amphetamine-induced dopamine efflux in the nucleus accumbens core and (ii) stress-evoked dopamine efflux in the nucleus accumbens shell. It has been proposed that a disruption in the interaction between cortical and subcortical dopamine neurons is involved in the pathophysiology of schizophrenia. The present data raise the possibility that a disruption in the interaction between mesocortical dopamine neurons and dopamine neurons projecting to the nucleus accumbens shell is involved in those symptoms of schizophrenia that are influenced by stress. PMID:9044382

  2. 25-Hydroxyvitamin D Depletion Does Not Exacerbate MPTP-Induced Dopamine Neuron Damage in Mice

    PubMed Central

    Dean, E. Danielle; Mexas, Lydia M.; Cpiro, Natalie L.; McKeon, Jeanne E.; DeLong, Mahlon R.; Pennell, Kurt D.; Doorn, Jonathan A.; Tangpricha, Vin; Miller, Gary W.; Evatt, Marian L.

    2012-01-01

    Recent clinical evidence supports a link between 25-hydroxyvitamin D insufficiency (serum 25-hydroxyvitamin D [25(OH)D] levels <30 ng/mL) and Parkinsons disease. To investigate the effect of 25(OH)D depletion on neuronal susceptibility to toxic insult, we induced a state of 25(OH)D deficiency in mice and then challenged them with the dopaminergic neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). We found there was no significant difference between control and 25(OH)D-deficient animals in striatal dopamine levels or dopamine transporter and tyrosine hydroxylase expression after lesioning with MPTP. Additionally, we found no difference in tyrosine hydroxylase expression in the substantia nigra pars compacta. Our data suggest that reducing 25(OH)D serum levels in mice has no effect on the vulnerability of nigral dopaminergic neurons in vivo in this model system of parkinsonism. PMID:22768297

  3. DOPAMINE DEPLETION SLOWS RETINAL TRANSMISSION

    EPA Science Inventory

    In male hooded rats, depletion of norepinephrine and dopamine by a-methyl-paratyrosine (AMT) significantly increased the latencies of early peaks in flash-evoked potentials recorded from the visual cortex, lateral geniculate nucleus, and optic tract. These effects were not produc...

  4. Dopamine Depletion of the Prefrontal Cortex Induces Dendritic Spine Loss: Reversal by Atypical Antipsychotic Drug Treatment

    PubMed Central

    Wang, Hui-Dong; Deutch, Ariel Y

    2016-01-01

    Dystrophic changes in dendrites of cortical neurons are present in several neuro-psychiatric disorders, including schizophrenia. The mechanisms that account for dendritic changes in the prefrontal cortex (PFC) in schizophrenia are unclear. Cognitive deficits in schizophrenia have been linked to compromised cortical dopamine function, and the density of the PFC dopamine innervation is decreased in schizophrenia. We determined if 6-hydroxydopamine lesions of the ventral tegmental area that disrupt the PFC dopamine innervation cause dystrophic changes in cortical neurons. Three weeks post-operatively we observed a marked decrease in basal dendritic length and spine density of layer V pyramidal cells in the prelimbic cortex; no change was seen in neurons of the motor cortex. We then examined rats in which the PFC dopamine innervation was lesioned and 3 weeks later were started on chronic treatment with an atypical (olanzapine) or typical (haloperidol) antipsychotic drug. Olanzapine but not haloperidol reversed lesion-induced changes in PFC pyramidal cell dendrites. These data suggest that dopamine regulates dendritic structure in PFC neurons. Moreover, the findings are consistent with a decrease in cortical dopaminergic tone contributing to the pathological changes in the cortex of schizophrenia, and suggest that the progressive cortical loss in schizophrenia may be slowed or reversed by treatment with atypical antipsychotic drugs. PMID:17687264

  5. Effects of discontinuing a high-fat diet on mitochondrial proteins and 6-hydroxydopamine-induced dopamine depletion in rats.

    PubMed

    Ma, Delin; Shuler, Jeffrey M; Raider, Kayla D; Rogers, Robert S; Wheatley, Joshua L; Geiger, Paige C; Stanford, John A

    2015-07-10

    Diet-induced obesity can increase the risk for developing age-related neurodegenerative diseases including Parkinson's disease (PD). Increasing evidence suggests that mitochondrial and proteasomal mechanisms are involved in both insulin resistance and PD. The goal of this study was to determine whether diet intervention could influence mitochondrial or proteasomal protein expression and vulnerability to 6-Hydroxydopamine (6-OHDA)-induced nigrostriatal dopamine (DA) depletion in rats' nigrostriatal system. After a 3 month high-fat diet regimen, we switched one group of rats to a low-fat diet for 3 months (HF-LF group), while the other half continued with the high-fat diet (HF group). A chow group was included as a control. Three weeks after unilateral 6-OHDA lesions, HF rats had higher fasting insulin levels and higher Homeostasis model assessment of insulin resistance (HOMA-IR), indicating insulin resistance. HOMA-IR was significantly lower in HF-LF rats than HF rats, indicating that insulin resistance was reversed by switching to a low-fat diet. Compared to the Chow group, the HF group exhibited significantly greater DA depletion in the substantia nigra but not in the striatum. DA depletion did not differ between the HF-LF and HF group. Proteins related to mitochondrial function (such as AMPK, PGC-1α), and to proteasomal function (such as TCF11/Nrf1) were influenced by diet intervention, or by 6-OHDA lesion. Our findings suggest that switching to a low-fat diet reverses the effects of a high-fat diet on systemic insulin resistance, and mitochondrial and proteasomal function in the striatum. Conversely, they suggest that the effects of the high-fat diet on nigrostriatal vulnerability to 6-OHDA-induced DA depletion persist. PMID:25862572

  6. Orbitofrontal Dopamine Depletion Upregulates Caudate Dopamine and Alters Behavior via Changes in Reinforcement Sensitivity

    PubMed Central

    Cardinal, R. N.; Rygula, R.; Hong, Y. T.; Fryer, T. D.; Sawiak, S. J.; Ferrari, V.; Cockcroft, G.; Aigbirhio, F. I.; Robbins, T. W.; Roberts, A. C.

    2014-01-01

    Schizophrenia is associated with upregulation of dopamine (DA) release in the caudate nucleus. The caudate has dense connections with the orbitofrontal cortex (OFC) via the frontostriatal loops, and both areas exhibit pathophysiological change in schizophrenia. Despite evidence that abnormalities in dopaminergic neurotransmission and prefrontal cortex function co-occur in schizophrenia, the influence of OFC DA on caudate DA and reinforcement processing is poorly understood. To test the hypothesis that OFC dopaminergic dysfunction disrupts caudate dopamine function, we selectively depleted dopamine from the OFC of marmoset monkeys and measured striatal extracellular dopamine levels (using microdialysis) and dopamine D2/D3 receptor binding (using positron emission tomography), while modeling reinforcement-related behavior in a discrimination learning paradigm. OFC dopamine depletion caused an increase in tonic dopamine levels in the caudate nucleus and a corresponding reduction in D2/D3 receptor binding. Computational modeling of behavior showed that the lesion increased response exploration, reducing the tendency to persist with a recently chosen response side. This effect is akin to increased response switching previously seen in schizophrenia and was correlated with striatal but not OFC D2/D3 receptor binding. These results demonstrate that OFC dopamine depletion is sufficient to induce striatal hyperdopaminergia and changes in reinforcement learning relevant to schizophrenia. PMID:24872570

  7. The MAO-B inhibitor deprenyl reduces the oral tremor and the dopamine depletion induced by the VMAT-2 inhibitor tetrabenazine.

    PubMed

    Podurgiel, Samantha J; Yohn, Samantha E; Dortche, Kristina; Correa, Merce; Salamone, John D

    2016-02-01

    Tetrabenazine (TBZ) is prescribed for the treatment of chorea associated with Huntington's disease. Via inhibition of the vesicular monoamine transporter (VMAT-2), TBZ blocks dopamine (DA) storage and depletes striatal DA; this drug also has been shown to induce Parkinsonian motor side effects in patients. Recently, TBZ was shown to induce tremulous jaw movements (TJMs) in rats and mice. TJMs are an oral tremor that has many of the characteristics of Parkinsonian tremor in humans. The present study focused upon the ability of the well-estabilished antiparkinsonian agent deprenyl to attenuate the behavioral and neurochemical effects of 2.0mg/kg TBZ. Deprenyl is a selective and irreversible inhibitor of monoamine oxidase-B, and administration of deprenyl produced a dose-related suppression of TBZ-induced TJMs. A second experiment employed in vivo microdialysis to examine extracellular DA levels in the ventrolateral striatum, the neostriatal region most closely associated with the production of TJMs, after administration of TBZ and deprenyl. Consistent with the behavioral data, TBZ alone produced a biphasic effect on extracellular DA, with an initial increases followed by a prolonged decrease during the period in which TJMs are displayed. Co-administration of deprenyl with TBZ increased DA levels compared to rats treated with TBZ alone. These results provide support for use of TBZ as a rodent model of Parkinsonism, and future studies should utilize this model to evaluate putative anti-Parkinsonian agents. PMID:26590367

  8. Dopamine Precursor Depletion Influences Pain Affect Rather than Pain Sensation

    PubMed Central

    Schulz, Enrico; Baumktter, Jochen; Ploner, Markus

    2014-01-01

    Pain is a multidimensional experience, which includes sensory, cognitive, and affective aspects. Converging lines of evidence indicate that dopaminergic neurotransmission plays an important role in human pain perception. However, the precise effects of dopamine on different aspects of pain perception remain to be elucidated. To address this question, we experimentally decreased dopaminergic neurotransmission in 22 healthy human subjects using Acute Phenylalanine and Tyrosine Depletion (APTD). During APTD and a control condition we applied brief painful laser stimuli to the hand, assessed different aspects of pain perception, and recorded electroencephalographic responses. APTD-induced decreases of cerebral dopaminergic activity did not influence sensory aspects of pain perception. In contrast, APTD yielded increases of pain unpleasantness. The increases of unpleasantness ratings positively correlated with effectiveness of APTD. Our finding of an influence of dopaminergic neurotransmission on affective but not sensory aspects of phasic pain suggests that analgesic effects of dopamine might be mediated by indirect effects on pain affect rather than by direct effects on ascending nociceptive signals. These findings contribute to our understanding of the complex relationship between dopamine and pain perception, which may play a role in various clinical pain states. PMID:24760082

  9. Relationships among rat ultrasonic vocalizations, behavioral measures of striatal dopamine loss, and striatal tyrosine hydroxylase immunoreactivity at acute and chronic time points following unilateral 6-hydroxydopamine-induced dopamine depletion.

    PubMed

    Grant, Laura M; Barnett, David G; Doll, Emerald J; Leverson, Glen; Ciucci, Michelle

    2015-09-15

    Voice deficits in Parkinson disease (PD) emerge early in the disease process, but do not improve with standard treatments targeting dopamine. Experimental work in the rat shows that severe and chronic unilateral nigrostriatal dopamine depletion with 6-OHDA results in decreased intensity, bandwidth, and complexity of ultrasonic vocalizations. However, it is unclear if mild/acute dopamine depletion, paralleling earlier stages of PD, results in vocalization deficits, or to what degree vocalization parameters are correlated with other dopamine-dependent indicators of lesion severity or percent of tyrosine hydroxylase (%TH) loss. Here, we assayed ultrasonic vocalizations, forelimb asymmetry, and apomorphine rotations in rats with a range of unilateral dopamine loss resulting from 6-OHDA or vehicle control infusions to the medial forebrain bundle at acute (72 h) and chronic (4 weeks) time points post-infusion. The %TH loss was evaluated at 4 weeks. At 72 h, forelimb asymmetry and %TH loss were significantly correlated, while at 4 weeks, all measures of lesion severity were significantly correlated with each other. Call complexity was significantly correlated with all measures of lesion severity at 72 h but only with %TH loss at 4 weeks. Bandwidth was correlated with forelimb asymmetry at both time points. Duration was significantly correlated with all dopamine depletion measures at 4 weeks. Notably, not all parameters were affected universally or equally across time. These results suggest that vocalization deficits may be a sensitive index of acute and mild catecholamine loss and further underscores the need to characterize the neural mechanisms underlying vocal deficits in PD. PMID:26026785

  10. Individual differences in dopamine level modulate the ego depletion effect.

    PubMed

    Dang, Junhua; Xiao, Shanshan; Liu, Ying; Jiang, Yumeng; Mao, Lihua

    2016-01-01

    Initial exertion of self-control impairs subsequent self-regulatory performance, which is referred to as the ego depletion effect. The current study examined how individual differences in dopamine level, as indexed by eye blink rate (EBR), would moderate ego depletion. An inverted-U-shaped relationship between EBR and subsequent self-regulatory performance was found when participants initially engaged in self-control but such relationship was absent in the control condition where there was no initial exertion, suggesting individuals with a medium dopamine level may be protected from the typical ego depletion effect. These findings are consistent with a cognitive explanation which considers ego depletion as a phenomenon similar to "switch costs" that would be neutralized by factors promoting flexible switching. PMID:26620929

  11. Cholesterol depletion induces autophagy

    SciTech Connect

    Cheng, Jinglei; Ohsaki, Yuki; Tauchi-Sato, Kumi; Fujita, Akikazu; Fujimoto, Toyoshi . E-mail: tfujimot@med.nagoya-u.ac.jp

    2006-12-08

    Autophagy is a mechanism to digest cells' own components, and its importance in many physiological and pathological processes is being recognized. But the molecular mechanism that regulates autophagy is not understood in detail. In the present study, we found that cholesterol depletion induces macroautophagy. The cellular cholesterol in human fibroblasts was depleted either acutely using 5 mM methyl-{beta}-cyclodextrin or 10-20 {mu}g/ml nystatin for 1 h, or metabolically by 20 {mu}M mevastatin and 200 {mu}M mevalonolactone along with 10% lipoprotein-deficient serum for 2-3 days. By any of these protocols, marked increase of LC3-II was detected by immunoblotting and by immunofluorescence microscopy, and the increase was more extensive than that caused by amino acid starvation, i.e., incubation in Hanks' solution for several hours. The induction of autophagic vacuoles by cholesterol depletion was also observed in other cell types, and the LC3-positive membranes were often seen as long tubules, >50 {mu}m in length. The increase of LC3-II by methyl-{beta}-cyclodextrin was suppressed by phosphatidylinositol 3-kinase inhibitors and was accompanied by dephosphorylation of mammalian target of rapamycin. By electron microscopy, autophagic vacuoles induced by cholesterol depletion were indistinguishable from those seen after amino acid starvation. These results demonstrate that a decrease in cholesterol activates autophagy by a phosphatidylinositol 3-kinase-dependent mechanism.

  12. Characterization of nociceptive response to chemical, mechanical, and thermal stimuli in adolescent rats with neonatal dopamine depletion.

    PubMed

    Ogata, M; Noda, K; Akita, H; Ishibashi, H

    2015-03-19

    Rats with dopamine depletion caused by 6-hydroxydopamine (6-OHDA) treatment during adulthood and the neonatal period exhibit akinetic motor activity and spontaneous motor hyperactivity during adolescence, respectively, indicating that the behavioral effects of dopamine depletion depend on the period of lesion development. Dopamine depletion during adulthood induces hyperalgesic response to mechanical, thermal, and/or chemical stimuli, whereas the effects of neonatal dopamine depletion on nociceptive response in adolescent rats are yet to be examined. The latter aspect was addressed in this study, and behavioral responses were examined using von-Frey, tail flick, and formalin tests. The formalin test revealed that rats with neonatal dopamine depletion exhibited a significant increase in nociceptive response during interphase (6-15min post formalin injection) and phase 2 (16-75min post formalin injection). This increase in nociceptive response to the formalin injection was not reversed by pretreatment with methamphetamine, which ameliorates motor hyperactivity observed in adolescent rats with neonatal 6-OHDA treatment. The von-Frey filament and tail flick tests failed to reveal significant differences in withdrawal thresholds between neonatal 6-OHDA-treated and vehicle-treated rats. The spinal neuronal response to the formalin injection into the rat hind paw was also examined through immunohistochemical analysis of c-Fos protein. Significantly increased numbers of c-Fos-immunoreactive cells were observed in laminae I-II and V-VI of the ipsilateral spinal cord to the site of the formalin injection in rats with neonatal dopamine depletion compared with vehicle-treated rats. These results suggest that the dopaminergic neural system plays a crucial role in the development of a neural network for tonic pain, including the spinal neural circuit for nociceptive transmission, and that the mechanism underlying hyperalgesia to tonic pain is not always consistent with that of spontaneous motor hyperactivity induced by neonatal dopamine depletion. PMID:25592423

  13. Dopamine and norepinephrine depletion in ring doves fed DDE, dieldrin, and Aroclor 1254

    USGS Publications Warehouse

    Heinz, G.H.; Hill, E.F.; Contrera, J.F.

    1980-01-01

    The levels of dopamine and norepinephrine were measured in one-half of the brain of ring doves fed a control diet or a diet containing 2, 20, or 200 ppm DDE; 1, 4, or 16 ppm dieldrin; or 1, 10, or 100 ppm Aroclor 1254. Levels of DDE, dieldrin, or Aroclor 1254 were determined in the other half of each brain. The intermediate and high levels of each chemical caused depletions in both neurotransmitters, and brain residues of each chemical were negatively correlated with levels of neurotransmitters. The highest concentrations of DDE, dieldrin, and Aroclor 1254 depressed averages of dopamine to 42.4, 41.4, and 45.2% of the control level and norepinephrine to 61.6, 62.0, and 56.9% of controls, respectively. Depletions of dopamine and norepinephrine could result in abnormal behavior of contaminated birds in the wild, and the detection of such depletions could become an important tool in assessing contaminant-induced behavioral aberrations in birds.

  14. Implantation of encapsulated catecholamine and GDNF-producing cells in rats with unilateral dopamine depletions and parkinsonian symptoms.

    PubMed

    Lindner, M D; Winn, S R; Baetge, E E; Hammang, J P; Gentile, F T; Doherty, E; McDermott, P E; Frydel, B; Ullman, M D; Schallert, T

    1995-03-01

    Studies in rodents suggest that PC12 cells, encapsulated in semipermeable ultrafiltration membranes and implanted in the striatum, have some potential efficacy for the treatment of age- and 6-OHD-induced sensorimotor impairments (22, 70, 71, 74). The objectives of this study were to: (1) determine if baby hamster kidney cells engineered to secrete glial cell line-derived neurotrophic factor (BHK-GDNF) would survive encapsulation and implantation in a dopamine-depleted rodent striatum, (2) compare polymer-encapsulated PC12 and PC12A cells in terms of their ability to survive and produce catecholamines in vivo in a dopamine-depleted striatum, and (3) determine if BHK-GDNF, PC12, or PC12A cells reduce parkinsonian symptoms in a rodent model of Parkinson's disease. Capsules with BHK-GDNF or PC12 cells contained viable cells after 90 days in vivo, with little evidence of host tissue damage/gliosis. In rats with tyrosine hydroxylase (TH)-positive fibers remaining in the lesioned striatum, there was TH-positive fiber ingrowth into the membranes of the BHK-GDNF capsules. PC12-containing capsules had higher basal release of both dopamine and L-DOPA after 90 days in vivo than before implantation, while basal release of both dopamine and L-DOPA decreased in the PC12A-containing capsules. Both encapsulated PC12 and PC12A cells, but not encapsulated BHK-GDNF cells, decreased apomorphine-induced rotations. Parkinsonian symptoms (akinesia, freezing/bracing, sensorimotor neglect) related to the extent of dopamine depletion were evident even in rats with dopamine depletions of only 25%. Evidence that encapsulated cells may attenuate these parkinsonian symptoms was not detected but most of the rats were more severely depleted of dopamine than Parkinson's patients (less than 2% dopamine remaining in the entire striatum), and these tests were not sensitive to differences between rats with less than 10% dopamine remaining. These results suggest that cell encapsulation technology can safely provide site-specific delivery of dopaminergic agonists or growth factors within the CNS, without requiring suppression of the immune system, and without using fetal tissue. Of the three types of encapsulated cells examined in the present study, PC12 cells seem to offer the most therapeutic potential in rats with severe dopamine depletions. PMID:7720827

  15. The presence of perforated synapses in the striatum after dopamine depletion, is this a sign of maladaptive brain plasticity?

    PubMed

    Anaya-Martnez, Vernica; Gutierrez-Valdez, Ana Luisa; Ordoez-Librado, Jose Luis; Montiel-Flores, Enrique; Snchez-Betancourt, Javier; Snchez Vzquez del Mercado, Csar; Reynoso-Erazo, Leonardo; Tron-Alvarez, Roco; Avila-Costa, Maria Rosa

    2014-12-01

    Synaptic plasticity is the process by which long-lasting changes take place at synaptic connections. The phenomenon itself is complex and can involve many levels of organization. Some authors separate forms into adaptations that have positive or negative consequences for the individual. It has been hypothesized that an increase in the number of synapses may represent a structural basis for the enduring expression of synaptic plasticity during some events that involve memory and learning; also, it has been suggested that perforated synapses increase in number after some diseases and experimental situations. The aim of this study was to analyze whether dopamine depletion induces changes in the synaptology of the corpus striatum of rats after the unilateral injection of 6-OHDA. The findings suggest that after the lesion, both contralateral and ipsilateral striata exhibit an increased length of the synaptic ending in ipsilateral (since third day) and contralateral striatum (since Day 20), loss of axospinous synapses in ipsilateral striatum and a significant increment in the number of perforated synapses, suggesting brain plasticity that might be deleterious for the spines, because this type of synaptic contacts are presumably excitatory, and in the absence of the modulatory effects of dopamine, the neuron could die through excitotoxic mechanisms. Thus, we can conclude that the presence of perforated synapses after striatal dopamine depletion might be a form of maladaptive synaptic plasticity. PMID:25246608

  16. High homocysteine induces betaine depletion

    PubMed Central

    Imbard, Apolline; Benoist, Jean-François; Esse, Ruben; Gupta, Sapna; Lebon, Sophie; de Vriese, An S; de Baulny, Helene Ogier; Kruger, Warren; Schiff, Manuel; Blom, Henk J.

    2015-01-01

    Betaine is the substrate of the liver- and kidney-specific betaine-homocysteine (Hcy) methyltransferase (BHMT), an alternate pathway for Hcy remethylation. We hypothesized that BHMT is a major pathway for homocysteine removal in cases of hyperhomocysteinaemia (HHcy). Therefore, we measured betaine in plasma and tissues from patients and animal models of HHcy of genetic and acquired cause. Plasma was collected from patients presenting HHcy without any Hcy interfering treatment. Plasma and tissues were collected from rat models of HHcy induced by diet and from a mouse model of cystathionine β-synthase (CBS) deficiency. S-adenosyl-methionine (AdoMet), S-adenosyl-homocysteine (AdoHcy), methionine, betaine and dimethylglycine (DMG) were quantified by ESI—LC–MS/MS. mRNA expression was quantified using quantitative real-time (QRT)-PCR. For all patients with diverse causes of HHcy, plasma betaine concentrations were below the normal values of our laboratory. In the diet-induced HHcy rat model, betaine was decreased in all tissues analysed (liver, brain, heart). In the mouse CBS deficiency model, betaine was decreased in plasma, liver, heart and brain, but was conserved in kidney. Surprisingly, BHMT expression and activity was decreased in liver. However, in kidney, BHMT and SLC6A12 expression was increased in CBS-deficient mice. Chronic HHcy, irrespective of its cause, induces betaine depletion in plasma and tissues (liver, brain and heart), indicating a global decrease in the body betaine pool. In kidney, betaine concentrations were not affected, possibly due to overexpression of the betaine transporter SLC6A12 where betaine may be conserved because of its crucial role as an osmolyte. PMID:26182429

  17. The effect of striatal dopamine depletion on striatal and cortical glutamate: A mini-review.

    PubMed

    Caravaggio, Fernando; Nakajima, Shinichiro; Plitman, Eric; Gerretsen, Philip; Chung, Jun Ku; Iwata, Yusuke; Graff-Guerrero, Ariel

    2016-02-01

    Understanding the interplay between the neurotransmitters dopamine and glutamate in the striatum has become the highlight of several theories of neuropsychiatric illnesses, such as schizophrenia. Using in vivo brain imaging in humans, alterations in dopamine and glutamate concentrations have been observed in several neuropsychiatric disorders. However, it is unclear a priori how alterations in striatal dopamine should modulate glutamate concentrations in the basal ganglia. In this selective mini-review, we examine the consequence of reducing striatal dopamine functioning on glutamate concentrations in the striatum and cortex; regions of interest heavily examined in the human brain imaging studies. We examine the predictions of the classical model of the basal ganglia, and contrast it with findings in humans and animals. The review concludes that chronic dopamine depletion (>4months) produces decreases in striatal glutamate levels which are consistent with the classical model of the basal ganglia. However, acute alterations in striatal dopamine functioning, specifically at the D2 receptors, may produce opposite affects. This has important implications for models of the basal ganglia and theorizing about neurochemical alterations in neuropsychiatric diseases. Moreover, these findings may help guide a priori hypotheses for (1)H-MRS studies measuring glutamate changes given alterations in dopaminergic functioning in humans. PMID:26334687

  18. Substantia nigra hyperechogenicity and CSF dopamine depletion in HIV.

    PubMed

    Obermann, Mark; Kper, M; Kastrup, O; Yaldizli, O; Esser, S; Thiermann, J; Koutsilieri, E; Arendt, G; Diener, H-C; Maschke, M

    2009-06-01

    Dopaminergic dysfunction is thought to play a pivotal role in human immunodeficiency virus (HIV)-related dementia. Decreased dopamine (DA) levels in the cerebrospinal fluid (CSF) and neuronal loss in the substantia nigra (SN) have been reported in HIV-infected patients, suggesting nigrostriatal damage. Structural changes detectable as hyperechogenicity in transcranial ultrasound (TCS) scans of the SN have been reported in patients with Parkinson's disease (PD) and other neurological conditions. In this study, we assessed the echomorphology of the SN in 40 HIV-positive patients compared to 40 age- and sex-matched healthy controls and correlated these findings with CSF levels of DA and the metabolites homovanillic acid (HVA) and 3,4-dihydroxy phenylacetic acid (DOPAC) and with neuropsychologic performance. We observed that the SN of HIV-infected patients was hyperechogenic relative to that of controls (0.07 +/- 0.05 vs. 0.04 +/- 0.07 cm(2); mean +/- SEM; P < 0.001) and that this SN hyperechogenicity was correlated with decreased DA levels in the CSF, decreased CD4 cell count, and an impaired performance in the psychopathology assessment scale (AMDP) subtest for drive and psychomobility. An association to CDC stage, duration of HIV infection, or presence of HIV dementia was not observed. Our results indicate changes in the nigrostriatal system in HIV-infected patients that are detectable as hyperechogenic SN precede prominent extrapyramidal symptoms and cognitive dysfunction. PMID:19240951

  19. The Effects of Acute Dopamine Precursor Depletion on the Reinforcing Value of Exercise in Anorexia Nervosa

    PubMed Central

    O’Hara, Caitlin B.; Keyes, Alexandra; Renwick, Bethany; Leyton, Marco; Campbell, Iain C.; Schmidt, Ulrike

    2016-01-01

    This study investigated whether dopaminergic systems are involved in the motivation to engage in behaviours associated with anorexia nervosa (AN), specifically, the drive to exercise. Women recovered from AN (AN REC, n = 17) and healthy controls (HC, n = 15) were recruited. The acute phenylalanine/tyrosine depletion (APTD) method was used to transiently decrease dopamine synthesis and transmission. The effect of dopamine precursor depletion on drive to exercise was measured using a progressive ratio (PR) exercise breakpoint task. Both groups worked for the opportunity to exercise, and, at baseline, PR breakpoint scores were higher in AN REC than HC. Compared to values on the experimental control session, APTD did not decrease PR breakpoint scores in AN REC, but significantly decreased scores in HC. These data show that women recovered from AN are more motivated to exercise than HC, although in both groups, activity is more reinforcing than inactivity. Importantly, decreasing dopamine does not reduce the motivation to exercise in people recovered from AN, but in contrast, does so in HC. It is proposed that in AN, drive to exercise develops into a behaviour that is largely independent of dopamine mediated reward processes and becomes dependent on cortico-striatal neurocircuitry that regulates automated, habit- or compulsive-like behaviours. These data strengthen the case for the involvement of reward, learning, habit, and dopaminergic systems in the aetiology of AN. PMID:26808920

  20. The Effects of Acute Dopamine Precursor Depletion on the Reinforcing Value of Exercise in Anorexia Nervosa.

    PubMed

    O'Hara, Caitlin B; Keyes, Alexandra; Renwick, Bethany; Leyton, Marco; Campbell, Iain C; Schmidt, Ulrike

    2016-01-01

    This study investigated whether dopaminergic systems are involved in the motivation to engage in behaviours associated with anorexia nervosa (AN), specifically, the drive to exercise. Women recovered from AN (AN REC, n = 17) and healthy controls (HC, n = 15) were recruited. The acute phenylalanine/tyrosine depletion (APTD) method was used to transiently decrease dopamine synthesis and transmission. The effect of dopamine precursor depletion on drive to exercise was measured using a progressive ratio (PR) exercise breakpoint task. Both groups worked for the opportunity to exercise, and, at baseline, PR breakpoint scores were higher in AN REC than HC. Compared to values on the experimental control session, APTD did not decrease PR breakpoint scores in AN REC, but significantly decreased scores in HC. These data show that women recovered from AN are more motivated to exercise than HC, although in both groups, activity is more reinforcing than inactivity. Importantly, decreasing dopamine does not reduce the motivation to exercise in people recovered from AN, but in contrast, does so in HC. It is proposed that in AN, drive to exercise develops into a behaviour that is largely independent of dopamine mediated reward processes and becomes dependent on cortico-striatal neurocircuitry that regulates automated, habit- or compulsive-like behaviours. These data strengthen the case for the involvement of reward, learning, habit, and dopaminergic systems in the aetiology of AN. PMID:26808920

  1. Orbitofrontal or accumbens dopamine depletion does not affect risk-based decision making in rats.

    PubMed

    Mai, Bettina; Hauber, Wolfgang

    2015-09-01

    Considerable evidence has implicated dopamine (DA) signals in target regions of midbrain DA neurons such as the medial prefrontal cortex or the core region of the nucleus accumbens in controlling risk-based decision-making. However, to date little is known about the contribution of DA in the orbitofrontal cortex (OFC) and the medial shell region of the nucleus accumbens (AcbS) to risk-based decision-making. Here we examined in rats the effects of 6-hydroxydopamine-induced DA depletions of the OFC and AcbS on risky choice using an instrumental two-lever choice task that requires the assessment of fixed within-session reward probabilities that were shifted across subsequent sessions, i.e., rats had to choose between two levers, a small/certain lever that delivered one certain food reward (one pellet at p = 1) and a large/risky lever that delivered a larger uncertain food reward with decreasing probabilities across subsequent sessions (four pellets at p = 0.75, 0.5, 0.25, 0.125, 0.0625). Results show that systemic administration of amphetamine or cocaine increased the preference for the large/risky lever. Results further demonstrate that, like sham controls, rats with OFC or AcbS DA depletion were sensitive to changes in probabilities for obtaining the large/risky reward across sessions and displayed probabilistic discounting. These findings point to the view that the basal capacity to evaluate the magnitude and likelihood of rewards associated with alternative courses of action as well as long-term changes of reward probabilities does not rely on DA input to the AcbS or OFC. PMID:25860659

  2. Tongue force and tongue motility are differently affected by unilateral vs bilateral nigrostriatal dopamine depletion in rats

    PubMed Central

    Nuckolls, Andrea L.; Worley, Cole; Leto, Christopher; Zhang, Hongyu; Morris, Jill K.; Stanford, John A.

    2012-01-01

    In addition to its cardinal symptoms of bradykinesia, muscle rigidity, resting tremor and postural disturbances, Parkinsons disease (PD) also affects orolingual motor function. Orolingual motor deficits can contribute to dysphagia, which increases morbidity and mortality in this population. Previous preclinical studies describing orolingual motor deficits in animal models of PD have focused on unilateral nigrostriatal dopamine (DA) depletion. In this study we compared the effects of unilateral vs bilateral 6-hydroxydopamine (6-OHDA)-induced DA depletion in rats trained to lick water from an isometric force-sensing disc. Rats received either unilateral or bilateral 6-OHDA into the medial forebrain bundle and were tested for four weeks post-lesion. Dependent variables included task engagement (the number of licks per session), tongue force (mean and maximum), and tongue motility (the number of licks per second). While both lesion groups exhibited decreased tongue force output, tongue motility deficits were present in only the group that received unilateral nigrostriatal DA depletion. Task engagement was not significantly diminished by 6-OHDA. Analysis of striatal DA tissue content revealed that DA depletion was ~97% in the unilateral group and ~90% in the bilateral group. These results suggest that while nigrostriatal DA depletion affects tongue force output, deficits in tongue motility may instead result from a functional imbalance in neural pathways affecting this midline structure. PMID:22796604

  3. Effects of asymmetric dopamine depletion on sensitivity to rewarding and aversive stimuli in Parkinson's disease.

    PubMed

    Maril, Sari; Hassin-Baer, Sharon; Cohen, Oren S; Tomer, Rachel

    2013-04-01

    The onset and progression of Parkinson's disease (PD) motor symptoms is generally asymmetric, reflecting differential extent of nigral pathology and resulting dopamine depletion in each of the hemispheres. Given the role of dopamine in processing rewarding and aversive events, and considering findings associating asymmetric neural activity with differential sensitivity to positive and negative stimuli, the current study examined the possibility that dopamine asymmetry in PD is related to differential approach and avoidance tendencies. An original task assessing and comparing sensitivity to positive and negative probabilistic feedback was administered to 29 right-handed participants with idiopathic PD, 16 with predominant right-side and 13 with predominant left-side motor symptoms, to compare the two groups. As dopamine replacement therapy (DRT) has shown different effects on reward and punishment processing, all participants were assessed in both off- and on-medication states. As predicted, when off medication, participants with relatively greater dopamine deficit in the left hemisphere minimized losses better than they increased gains, while those with a greater right hemisphere deficit showed a trend toward the opposite pattern. Medication reversed the relationship between gain and loss sensitivity in the left-hemisphere PD group, but not in the right-hemisphere group. Particularly in the left-hemisphere PD group, findings support the possibility that subcortical dopaminergic asymmetry is reflected in behaviorally-expressed approach and avoidance tendencies. Furthermore, the effects of DRT on approach and avoidance appear to interact with asymmetry, shedding light on previous conclusions regarding the role of dopamine in reinforcement processing. PMID:23422331

  4. Phasic-like stimulation of the medial forebrain bundle augments striatal gene expression despite methamphetamine-induced partial dopamine denervation.

    PubMed

    Howard, Christopher D; Pastuzyn, Elissa D; Barker-Haliski, Melissa L; Garris, Paul A; Keefe, Kristen A

    2013-05-01

    Methamphetamine-induced partial dopamine depletions are associated with impaired basal ganglia function, including decreased preprotachykinin mRNA expression and impaired transcriptional activation of activity-regulated, cytoskeleton-associated (Arc) gene in striatum. Recent work implicates deficits in phasic dopamine signaling as a potential mechanism linking methamphetamine-induced dopamine loss to impaired basal ganglia function. This study thus sought to establish a causal link between phasic dopamine transmission and altered basal ganglia function by determining whether the deficits in striatal neuron gene expression could be restored by increasing phasic dopamine release. Three weeks after pretreatment with saline or a neurotoxic regimen of methamphetamine, rats underwent phasic- or tonic-like stimulation of ascending dopamine neurons. Striatal gene expression was examined using in situ hybridization histochemistry. Phasic-like, but not tonic-like, stimulation induced immediate-early genes Arc and zif268 in both groups, despite the partial striatal dopamine denervation in methamphetamine-pretreated rats, with the Arc expression occurring in presumed striatonigral efferent neurons. Phasic-like stimulation also restored preprotachykinin mRNA expression. These results suggest that disruption of phasic dopamine signaling likely underlies methamphetamine-induced impairments in basal ganglia function, and that restoring phasic dopamine signaling may be a viable approach to manage long-term consequences of methamphetamine-induced dopamine loss on basal ganglia functions. PMID:23480199

  5. Amphetamine induces dopamine efflux through a dopamine transporter channel

    PubMed Central

    Kahlig, Kristopher M.; Binda, Francesca; Khoshbouei, Habibeh; Blakely, Randy D.; McMahon, Douglas G.; Javitch, Jonathan A.; Galli, Aurelio

    2005-01-01

    Drugs of abuse, including cocaine, amphetamine (AMPH), and heroin, elevate extracellular dopamine (DA) levels in the brain, thereby altering the activity/plasticity of reward circuits and precipitating addiction. The physiological release of DA occurs through the calcium-dependent fusion of a synaptic vesicle with the plasma membrane. Extracellular DA is cleared by uptake through the Na+/Cl--dependent DA transporter (DAT). In contrast, the substrate AMPH induces nonvesicular release of DA mediated by DAT. Extracellular AMPH is generally believed to trigger DA efflux through DAT by facilitating exchange for cytosolic DA. Here, in outside-out patches from heterologous cells stably expressing DAT or from dopaminergic neurons, by using ionic conditions in the patch pipette that mimic those produced by AMPH stimulation, we report that AMPH causes DAT-mediated DA efflux by two independent mechanisms: (i) a slow process consistent with an exchange mechanism and (ii) a process that results in rapid (millisecond) bursts of DA efflux through a channel-like mode of DAT. Because channel-like release of DA induced by AMPH is rapid and contains a large number of DA molecules, with a single burst of DA on par with a quantum of DA from exocytotic release of a vesicle, this burst mode of release may play a role in the synaptic actions and psychostimulant properties of AMPH and related compounds. Unlike AMPH, the endogenous substrate DA, when present on both sides of the plasma membrane, inhibits this channel-like activity, thereby suggesting that the DAT channel-like mode cannot accumulate DA against a concentration gradient. PMID:15728379

  6. Neural correlates of sleepiness induced by catecholamine depletion

    PubMed Central

    Meyers, Noah; Fromm, Stephen; Luckenbaugh, David A.; Drevets, Wayne C.; Hasler, Gregor

    2011-01-01

    Although extensive indirect evidence exists to suggest that the central dopaminergic system plays a significant role in the modulation of arousal, the functional effect of the dopaminergic influence on the regulation of the sleep-wake cycle remains unclear. Thirteen healthy volunteers and 15 unmedicated subjects with a history of major depressive disorder underwent catecholamine depletion (CD) using oral alpha-methyl-para-tyrosine in a randomized, placebo-controlled, double-blind, crossover study. The main outcome measures in both sessions were sleepiness (Stanford-Sleepiness-Scale), cerebral glucose metabolism (positron emission tomography), and serum prolactin concentration. CD consistently induced clinically relevant sleepiness in both groups (p<0.0001). The CD-induced prolactin increase correlated with CD-induced sleepiness (r=0.71, p<0.0001) but not with CD-induced mood and anxiety symptoms (p?0.2). CD-induced sleepiness correlated with CD-induced increases in metabolism in the medial and orbital frontal cortex, bilateral superior temporal cortex, left insula, cingulate motor area and in the vicinity of the periaqueductal gray. This study suggests that the association between dopamine depletion and sleepiness is independent of the brain reward system and the risk for depression. The visceromotor system, the cingulate motor area, the periaqueductal gray and the caudal hypothalamus may mediate the impact of the dopaminergic system on regulation of wakefulness and sleep. PMID:21872452

  7. Neurturin Protects Against 6-Hydroxydopamine-Induced Reductions in Evoked Dopamine Overflow in Rat Striatum

    PubMed Central

    Cass, Wayne A.; Peters, Laura E.

    2010-01-01

    Neurturin (NTN), a member of the glial cell line-derived neurotrophic factor (GDNF) family, has substantial effects on normal and lesioned nigrostriatal dopamine systems. However, its ability to protect against toxin-induced loss of striatal dopamine release has not been previously reported. The goal of the present study was to determine if NTN could protect against 6-hydroxydopamine (6-OHDA)-induced reductions in striatal dopamine overflow and tissue levels of dopamine, and to compare the effects of NTN with those of GDNF. Male Fischer-344 rats were given a single injection of vehicle, or 5 ?g NTN or GDNF, into the right striatum. The following day the animals were given a single injection of 12 ?g 6-OHDA into the striatum at the same site where the trophic factor was injected. Microdialysis experiments conducted three weeks later indicated that the 6-OHDA decreased basal levels of dopamine and metabolites in the lesioned striatum compared to the contralateral striatum, and NTN was able to partially protect against the 6-OHDA-induced reductions. Injection of NTN one day prior to 6-OHDA also led to significant protection against loss of both potassium and amphetamine evoked overflow of dopamine. The NTN treatments partially protected against 6-OHDA-induced reductions in striatal tissue levels of dopamine, and completely protected against loss of nigral dopamine content. The protective effects of NTN were similar in magnitude to those of GDNF. These results support that within the experimental parameters used in this study, NTN is as effective as GDNF in protecting against the dopamine-depleting effects of intrastriatal 6-OHDA. PMID:20615442

  8. Dopamine depletion, stimulation or blockade in the rat disrupts spatial navigation and locomotion dependent upon beacon or distal cues.

    PubMed

    Whishaw, I Q; Dunnett, S B

    1985-01-01

    Rats depleted of dopamine by intraventricular or nigrostriatal bundle 6-hydroxydopamine injection were compared with normal rats on acquisition and retention of place and cue navigation in the Morris swimming pool test and on a battery of sensorimotor tests. Rats with extensive bilateral dopamine depletions were able to swim vigorously, but were unable to acquire either the place or cue task. Rats with unilateral lesions, although impaired in the rate of acquisition were eventually able to learn both tasks to close to normal levels. Animals pretrained on the tasks prior to the lesions displayed retention deficits that were related to the extent of dopamine depletion: after extensive depletions, performance on both tasks deteriorated until successful navigation was abolished, whereas incomplete depletions impaired but did not abolish performance on either task. In separate groups of pretrained animals, both dopamine antagonists (haloperidol, alpha-flupenthixol) and agonists (apomorphine, metamphetamine) blocked performance on both place and cue tasks, although there were individual differences in sensitivity of the rats. Performance on the place task was more sensitive to disruption than the cue task both by the lesions and by haloperidol, alpha-flupenthixol or apormorphine but not by metamphetamine. On the sensorimotor tests dopamine-depleted rats were impaired at visual but not contact placing, they oriented weakly to snout touches and surfaces but not to distal stimuli, and they were akinetic on a number of tests of motor function but when wet they displayed as many grooming movements and groomed as long as did normal rats. The results suggest that dopamine depletion may impair spatial navigation by a disruption of their ability to use distal cues for guidance. PMID:3911980

  9. Dopamine precursor depletion improves punishment prediction during reversal learning in healthy females but not males

    PubMed Central

    Standing, Holly R.; DeVito, Elise E.; Cools, Roshan; Sahakian, Barbara J.

    2010-01-01

    Introduction The neurotransmitter dopamine has frequently been implicated in reward processing but is also, increasingly, implicated in punishment processing. We have previously shown that both patients with Parkinson's disease and healthy individuals with low dopamine (DA) synthesis are better at reversal learning based on punishment than reward. Here, we extend these prior findings by examining the effects of artificially reducing DA synthesis in healthy individuals performing this previously employed task. Methods In a double-blind, placebo-controlled crossover design, we applied the acute tyrosine and phenylalanine depletion (ATPD) procedure to reduce global DA synthesis in 15 female and 14 male subjects. Each subject performed the reward- and punishment-based reversal-learning paradigm. Results There was a significant three-way interaction between ATPD, the valence of the outcome signalling reversal and the gender of the participants. Examination of punishment and reward-based reversals separately revealed that this was driven by a significant improvement in punishment processing in female but not male subjects following DA depletion. Conclusions Reducing DA synthesis in healthy individuals shifted sensitivity of performance from reward to punishment processing. Gender differences in DA synthesis might underlie the selectivity of this effect to female subjects. Such gender biases may go some way towards explaining the gender biases in certain psychiatric disorders such as depression and Parkinson's disease. PMID:20495788

  10. Mesocortical dopamine depletion and anxiety-related behavior in the rat: sex and hemisphere differences.

    PubMed

    Sullivan, R M; Dufresne, M M; Siontas, D; Chehab, S; Townsend, J; Laplante, F

    2014-10-01

    The mesocortical dopamine (DA) system of the rat plays an important role in prefrontal cortex (PFC) regulation of stress and emotion and exhibits functional hemispheric asymmetry for such processing. Since few studies examine sex differences in this context, we compared the effects of left vs. right unilateral PFC DA depletion in males and females in several behavioral situations associated with anxiety or aversion. Adult rats received unilateral injections of 6-hydroxydopamine (6-OHDA) or vehicle in the ventromedial (vm) PFC. Behavioral tests included a predator odor burying test, elevated plus maze and sucrose consumption with simple taste aversion. Tissue analysis confirmed that vmPFCs injected with 6-OHDA were depleted of DA (75-85%) compared to controls. Burying behavior and sucrose consumption were affected only by left lesions, similarly in both sexes. However, risk assessment behaviors were affected by right lesions in opposite directions in males and females. Behaviors modified preferentially by the left cortex thus showed less evidence of sex differences than those modulated by the right. While mesocortical DA depletion effects are lateralized, the nature of these effects can vary with sex and specific behavior. Such findings may be clinically significant, given the large gender differences in the incidence of mood and anxiety disorders, which also show many lateralized prefrontal abnormalities. PMID:24819821

  11. [Pathological gambling induced by dopamine agonists].

    PubMed

    Gahr, M; Connemann, B J; Schnfeldt-Lecuona, C J

    2011-08-01

    Problems with impulse control and pathological gambling are known as possible side effects of dopaminergic therapy in patients with Parkinson's disease. We report 2 cases of pathological gambling induced by dopamine agonists in patients without Parkinson's disease. The first patient, a 46-year-old man, was treated with ropinirole for restless legs syndrome and had lost huge amounts of money in the context of internet-based poker game. Another 46-year-old male patient developed pathological gambling under treatment with cabergoline administered for prolactinoma. The two cases implicate pathological gambling as a possible consequence of dopaminergic treatment and support the increasing evidence regarding pathological gambling as an adverse drug reaction of dopaminergic treatment, also in patients who do not suffer from Parkinson's disease. PMID:21809260

  12. Alteration of Daily and Circadian Rhythms following Dopamine Depletion in MPTP Treated Non-Human Primates

    PubMed Central

    Fifel, Karim; Vezoli, Julien; Dzahini, Kwamivi; Claustrat, Bruno; Leviel, Vincent; Kennedy, Henry; Procyk, Emmanuel; Dkhissi-Benyahya, Ouria; Gronfier, Claude; Cooper, Howard M.

    2014-01-01

    Disturbances of the daily sleep/wake cycle are common non-motor symptoms of Parkinson's disease (PD). However, the impact of dopamine (DA) depletion on circadian rhythms in PD patients or non-human primate (NHP) models of the disorder have not been investigated. We evaluated alterations of circadian rhythms in NHP following MPTP lesion of the dopaminergic nigro-striatal system. DA degeneration was assessed by in vivo PET ([11C]-PE2I) and post-mortem TH and DAT quantification. In a light?dark cycle, control and MPTP-treated NHP both exhibit rest-wake locomotor rhythms, although DA-depleted NHP show reduced amplitude, decreased stability and increased fragmentation. In all animals, 6-sulphatoxymelatonin peaks at night and cortisol in early morning. When the circadian system is challenged by exposure to constant light, controls retain locomotor rest-wake and hormonal rhythms that free-run with stable phase relationships whereas in the DA-depleted NHP, locomotor rhythms are severely disturbed or completely abolished. The amplitude and phase relations of hormonal rhythms nevertheless remain unaltered. Use of a light-dark masking paradigm shows that expression of daily rest-wake activity in MPTP monkeys requires the stimulatory and inhibitory effects of light and darkness. These results suggest that following DA lesion, the central clock in the SCN remains intact but, in the absence of environmental timing cues, is unable to drive downstream rhythmic processes of striatal clock gene and dopaminergic functions that control locomotor output. These findings suggest that the circadian component of the sleep-wake disturbances in PD is more profoundly affected than previously assumed. PMID:24465981

  13. Age moderates the effect of acute dopamine depletion on passive avoidance learning.

    PubMed

    Kelm, Mary Katherine; Boettiger, Charlotte Ann

    2015-04-01

    Despite extensive links between reinforcement-based learning and dopamine (DA), studies to date have not found consistent effects of acute DA reduction on reinforcement learning in both men and women. Here, we tested the effects of reducing DA on reward- and punishment-based learning using the deterministic passive avoidance learning (PAL) task. We tested 16 (5 female) adults (ages 22-40) in a randomized, cross-over design to determine whether reducing global DA by administering an amino acid beverage deficient in the DA precursors, phenylalanine and tyrosine (P/T[-]), would affect PAL task performance. We found that P/T[-] beverage effects on PAL performance were modulated by age. Specifically, we found that P/T depletion significantly improved learning from punishment with increasing participant age. Participants committed 1.49 fewer passive avoidance errors per additional year of age (95% CI, -0.71 - -2.27, r=-0.74, p=0.001). Moreover, P/T depletion improved learning from punishment in adults (ages 26-40) while it impaired learning from punishment in emerging adults (ages 22-25). We observed similar, but non-significant trends in learning from reward. While there was no overall effect of P/T-depletion on reaction time (RT), there was a relationship between the effect of P/T depletion on PAL performance and RT; those who responded more slowly on the P/T[-] beverage also made more errors on the P/T[-] beverage. When P/T-depletion slowed RT after a correct response, there was a worsening of PAL task performance; there was no similar relationship for the RT after an incorrect response and PAL task performance. Moreover, among emerging adults, changes in mood on the P/T[-] beverage negatively correlated with learning from reward on the P/T[-] beverage. Together, we found that both reward- and punishment-based learning are sensitive to central catecholamine levels, and that these effects of acute DA reduction vary with age. PMID:25636601

  14. Lipopolysaccharide-induced mitochondrial DNA depletion.

    PubMed

    Choumar, Amal; Tarhuni, Arige; Lettron, Philippe; Reyl-Desmars, Florence; Dauhoo, Nismah; Damasse, Julie; Vadrot, Nathalie; Nahon, Pierre; Moreau, Richard; Pessayre, Dominique; Mansouri, Abdellah

    2011-12-01

    Hepatic energy depletion has been described in severe sepsis, and lipopolysaccharide (LPS) has been shown to cause mitochondrial DNA (mtDNA) damage. To clarify the mechanisms of LPS-induced mtDNA damage and mitochondrial alterations, we treated wild-type (WT) or transgenic manganese superoxide dismutase-overerexpressing (MnSOD(+++)) mice with a single dose of LPS (5 mg/kg). In WT mice, LPS increased mitochondrial reactive oxygen species formation, hepatic inducible nitric oxide synthase (NOS) mRNA and protein, tumor necrosis factor-alpha, interleukin-1 beta, and high-mobility group protein B1 concentrations. Six to 48 h after LPS administration (5 mg/kg), liver mtDNA levels, respiratory complex I activity, and adenosine triphosphate (ATP) contents were decreased. In addition, LPS increased interferon-? concentration and decreased mitochondrial transcription factor A (Tfam) mRNA, Tfam protein, and mtDNA-encoded mRNAs. Morphological studies showed mild hepatic inflammation. The LPS (5 mg/kg)-induced mtDNA depletion, complex I inactivation, ATP depletion, and alanine aminotransferase increase were prevented in MnSOD(+++) mice or in WT mice cotreated with 1400W (a NOS inhibitor), (2-(2,2,6,6-tetramethylpiperidin-1-oxyl-4-ylamino)-2-oxoethyl)triphenylphosphonium chloride, monohydrate (a superoxide scavenger) or uric acid (a peroxynitrite scavenger). The MnSOD overexpression delayed death in mice challenged by a higher, lethal dose of LPS (25 mg/kg). In conclusion, LPS administration damages mtDNA and alters mitochondrial function. The protective effects of MnSOD, NOS inhibitors, and superoxide or peroxynitrite scavengers point out a role of the superoxide anion reacting with NO to form mtDNA- and protein-damaging peroxynitrite. In addition to the acute damage caused by reactive species, decreased levels of mitochondrial transcripts contribute to mitochondrial dysfunction. PMID:21767162

  15. Lack of evidence for reduced prefrontal cortical serotonin and dopamine efflux after acute tryptophan depletion

    PubMed Central

    Meerkerk, Dorie (T). J.; Lieben, Cindy K. J.; Blokland, Arjan; Feenstra, Matthijs G. P.

    2007-01-01

    Rationale Acute tryptophan depletion (ATD) is a widely used method to study the role of serotonin (5-HT) in affect and cognition. ATD results in a strong but transient decrease in plasma tryptophan and central 5-HT synthesis and availability. Although its use is widespread, the evidence that the numerous functional effects of ATD are caused by actual changes in 5-HT neuronal release is not very strong. Thus far, decreases in 5-HT efflux (thought to reflect synaptic release) were only reported after chronic tryptophan depletion or when ATD was combined with blockade of 5-HT reuptake. Objective With the current experiment, we aimed to study the validity of the method of ATD by measuring the extent to which it reduces the efflux of 5-HT (and dopamine) in the prefrontal cortex in the absence of reuptake blockage. Materials and methods We simultaneously measured in freely moving animals plasma tryptophan via a catheter in the jugular vein and 5-HT and DA efflux in the medial prefrontal cortex through microdialysis after ATD treatment. Results ATD reduced plasma tryptophan to less than 30% of control, without affecting 5-HT or DA efflux in the prefrontal cortex, indicating that even strong reductions of plasma tryptophan do not necessarily result in decreases in central 5-HT efflux. Conclusion The present experiment showed that reductions in plasma tryptophan, similar to values associated with behavioural effects, do not necessarily reduce 5-HT efflux and suggest that the cognitive and behavioural effects of ATD may not be (exclusively) due to alterations in 5-HT release. PMID:17713760

  16. Dopamine release from serotonergic nerve fibers is reduced in L-DOPA-induced dyskinesia

    PubMed Central

    Nevalainen, Nina; af Bjerkn, Sara; Lundblad, Martin; Gerhardt, Greg A.; Strmberg, Ingrid

    2011-01-01

    L-DOPA (3,4-dihydroxyphenyl-L-alanine) is the most commonly used treatment for symptomatic control in patients with Parkinsons disease. Unfortunately, most patients develop severe side effects, such as dyskinesia, upon chronic L-DOPA treatment. The patophysiology of dyskinesia is unclear, however, involvement of serotonergic nerve fibers in converting L-DOPA to dopamine has been suggested. Therefore, potassium-evoked dopamine release was studied after local application of L-DOPA in the striata of normal, dopamine- and dopamine/serotonin-lesioned L-DOPA nave, and dopamine-denervated chronically L-DOPA-treated dyskinetic rats using in vivo chronoamperometry. The results revealed that local L-DOPA administration into normal and intact hemisphere of dopamine-lesioned L-DOPA nave animals significantly increased the potassium-evoked dopamine release. L-DOPA application also increased the dopamine peak amplitude in the dopamine-depleted L-DOPA nave striatum, although these dopamine levels were several-folds lower than in the normal striatum, while no increased dopamine release was found in the dopamine/serotonin-denervated striatum. In dyskinetic animals, local L-DOPA application did not affect the dopamine release, resulting in significantly attenuated dopamine levels compared to those measured in L-DOPA nave dopamine-denervated striatum. To conclude, L-DOPA is most likely converted to dopamine in serotonergic nerve fibers in the dopamine-depleted striatum, but the dopamine release is several-fold lower than in normal striatum. Furthermore, L-DOPA loading does not increase the dopamine release in dyskinetic animals as found in L-DOPA nave animals, despite similar density of serotonergic innervation. Thus, the dopamine overflow produced from the serotonergic nerve fibers appears not to be the major cause of dyskinetic behavior. PMID:21534956

  17. Deletion of Go2? abolishes cocaine-induced behavioral sensitization by disturbing the striatal dopamine system

    PubMed Central

    Brunk, Irene; Blex, Christian; Sanchis-Segura, Carles; Sternberg, Jan; Perreau-Lenz, Stephanie; Bilbao, Ainhoa; Hrtnagl, Heide; Baron, Jens; Juranek, Judyta; Laube, Gregor; Birnbaumer, Lutz; Spanagel, Rainer; Ahnert-Hilger, Gudrun

    2008-01-01

    The ?-subunits of the trimeric Go class of GTPases, comprising the splice variants Go1? and Go2?, are abundantly expressed in brain and reside on both plasma membrane and synaptic vesicles. Go2? is involved in the vesicular storage of monoamines but its physiological relevance is still obscure. We now show that genetic depletion of Go2? reduces motor activity induced by dopamine-enhancing drugs like cocaine, as repeated injections of cocaine fail to provoke behavioral sensitization in Go2??/? mice. In Go2??/? mice, D1 receptor signaling in the striatum is attenuated due to a reduced expression of Golf? and Gs?. Following cocaine treatment, Go2??/? mice have lower D1 and higher D2 receptor amounts compared to wild-type mice. The lack of behavioral sensitization correlates with reduced dopamine levels in the striatum and decreased expression of tyrosine hydroxylase. One reason for the neurochemical changes may be a reduced uptake of monoamines by synaptic vesicles from Go2??/? mice as a consequence of a lowered set point for filling. We conclude that Go2? optimizes vesicular filling which is instrumental for normal dopamine functioning and for the development of drug-induced behavioral sensitization.Brunk, I., Blex, C., Sanchis-Segura, C., Sternberg, J., Perreau-Lenz, S., Bilbao, A., Hrtnagl, H., Baron, J., Juranek, J., Laube, G., Birnbaumer, L., Spanagel, R., Ahnert-Hilger, G. Deletion of Go2? abolishes cocaine-induced behavioral sensitization by disturbing the striatal dopamine system. PMID:18606864

  18. Dopamine in the ink defence system of Sepia officinalis: biosynthesis, vesicular compartmentation in mature ink gland cells, nitric oxide (NO)/cGMP-induced depletion and fate in secreted ink.

    PubMed Central

    Fiore, Gabriella; Poli, Annarita; Di Cosmo, Anna; d'Ischia, Marco; Palumbo, Anna

    2004-01-01

    The biosynthesis, localization and fate of catecholamines in the ink gland of the cuttlefish Sepia officinalis were investigated by combined biochemical and immunohistocytochemical methodologies. HPLC analysis of crude ink gland extracts indicated the presence of dopa (2.18+/-0.82 nmol/mg of protein) and DA (dopamine, 0.06+/-0.02 nmol/mg of protein), but no detectable noradrenaline or adrenaline. DA was shown to derive from L-tyrosine, according to experiments performed by incubating intact ink glands with [L-14C]tyrosine. The biosynthetic process involves a tyrosine hydroxylase and a dopa decarboxylase pathway and is independent of tyrosinase. The tyrosine hydroxylase activity was detected under conditions of tyrosinase suppression in the cytosolic fraction, but not in the melanosomal fraction, of ink gland extracts, and the presence of the enzyme was confirmed by Western-blot analysis. Dopa and DA were found to be released from the ink glands by processes controlled through the NMDA-nitric oxide-cGMP (where NMDA stands for N -methyl-D-aspartate) signalling pathway, as apparent from incubation experiments performed with [L-14C]tyrosine in the presence of NMDA, diethylamine NONOate (diethylamine diazeniumdiolate), a nitric oxide donor, 8-bromo-cGMP or a guanylyl cyclase inhibitor. Immunohistochemical results coupled with electron microscopy indicated that DA was concentrated in vesicles specifically localized in the mature melanin-producing cells of the ink gland proximal to the lumen and separated from the melanin-containing melanosomes. NMDA receptor stimulation or exposure to an NO donor caused a marked loss of DA immunoreactivity in mature cells, consistent with a release process. In the lumen of the ink gland, where mature exhausted cells pour their contents, DA immunoreactivity was found to be associated with the melanin granules, due apparently to physical adsorption. Overall, these results point to DA as a marker of cell maturation in Sepia ink gland subject to release by the NO/cGMP signalling pathway, and disclose apparently overlooked DA-melanin interactions in secreted ink of possible relevance to the defence mechanism. PMID:14670074

  19. Dopamine alleviates salt-induced stress in Malus hupehensis.

    PubMed

    Li, Chao; Sun, Xiangkai; Chang, Cong; Jia, Dongfeng; Wei, Zhiwei; Li, Cuiying; Ma, Fengwang

    2015-04-01

    Dopamine mediates many physiological processes in plants. We investigated its role in regulating growth, ion homeostasis and the response to salinity in Malus hupehensis Rehd. Both hydroponics and field-pot experiments were conducted under saline conditions. Salt-stressed plants had reduced growth and a marked decline in their net photosynthetic rates, values for Fv /Fm and chlorophyll contents. However, pretreatment with 100 or 200 μM dopamine significantly alleviated this inhibition and enabled plants to maintain their photosynthetic capacity. In addition to changing stomatal behavior, supplementation with dopamine positively influenced the uptake of K, N, P, S, Cu and Mn ions but had an inhibitory effect on Na and Cl uptake, the balance of which is responsible for managing the response to salinity by Malus plants. Dopamine pretreatment also controlled the burst of hydrogen peroxide, possibly through direct scavenging and by enhancing the activities of antioxidative enzymes and the capacity of the ascorbate-glutathione cycle. We also investigated whether dopamine might regulate salt overly sensitive pathway genes under salinity. Here, MdHKT1, MdNHX1 and MdSOS1 were greatly upregulated in roots and leaves, which possibly contributed to the maintenance of ion homeostasis and, thus, improved salinity resistance in plants exposed earlier to exogenous dopamine. These results support our conclusion that dopamine alleviates salt-induced stress not only at the level of antioxidant defense but also by regulating other mechanisms of ion homeostasis. PMID:25155951

  20. Dopamine-Induced Conformational Changes in Alpha-Synuclein

    PubMed Central

    Outeiro, Tiago F.; Klucken, Jochen; Bercury, Kathryn; Tetzlaff, Julie; Putcha, Preeti; Oliveira, Luis M. A.; Quintas, Alexandre; McLean, Pamela J.; Hyman, Bradley T.

    2009-01-01

    Background Oligomerization and aggregation of ?-synuclein molecules play a major role in neuronal dysfunction and loss in Parkinson's disease [1]. However, ?-synuclein oligomerization and aggregation have mostly been detected indirectly in cells using detergent extraction methods [2], [3], [4]. A number of in vitro studies showed that dopamine can modulate the aggregation of ?-synuclein by inhibiting the formation of or by disaggregating amyloid fibrils [5], [6], [7]. Methodology/Principal Findings Here, we show that ?-synuclein adopts a variety of conformations in primary neuronal cultures using fluorescence lifetime imaging microscopy (FLIM). Importantly, we found that dopamine, but not dopamine agonists, induced conformational changes in ?-synuclein which could be prevented by blocking dopamine transport into the cell. Dopamine also induced conformational changes in ?-synuclein expressed in neuronal cell lines, and these changes were also associated with alterations in oligomeric/aggregated species. Conclusion/Significance Our results show, for the first time, a direct effect of dopamine on the conformation of ?-synuclein in neurons, which may help explain the increased vulnerability of dopaminergic neurons in Parkinson's disease. PMID:19730729

  1. Dopamine and Pain Sensitivity: Neither Sulpiride nor Acute Phenylalanine and Tyrosine Depletion Have Effects on Thermal Pain Sensations in Healthy Volunteers

    PubMed Central

    Becker, Susanne; Ceko, Marta; Louis-Foster, Mytsumi; Elfassy, Nathaniel M.; Leyton, Marco; Shir, Yoram; Schweinhardt, Petra

    2013-01-01

    Based on animal studies and some indirect clinical evidence, dopamine has been suggested to have anti-nociceptive effects. Here, we investigated directly the effects of increased and decreased availability of extracellular dopamine on pain perception in healthy volunteers. In Study 1, participants ingested, in separate sessions, a placebo and a low dose of the centrally acting D2-receptor antagonist sulpiride, intended to increase synaptic dopamine via predominant pre-synaptic blockade. No effects were seen on thermal pain thresholds, tolerance, or temporal summation. Study 2 used the acute phenylalanine and tyrosine depletion (APTD) method to transiently decrease dopamine availability. In one session participants ingested a mixture that depletes the dopamine amino acid precursors, phenylalanine and tyrosine. In the other session they ingested a nutritionally balanced control mixture. APTD led to a small mood-lowering response following aversive thermal stimulation, but had no effects on the perception of cold, warm, or pain stimuli. In both studies the experimental manipulation of dopaminergic neurotransmission was successful as indicated by manipulation checks. The results contradict proposals that dopamine has direct anti-nociceptive effects in acute experimental pain. Based on dopamines well-known role in reward processing, we hypothesize that also in the context of pain, dopamine acts on stimulus salience and might play a role in the initiation of avoidance behavior rather than having direct antinociceptive effects in acute experimental pain. PMID:24236199

  2. Fluoxetine increases long-lasting neostriatal dopamine depletion after administration of d-methamphetamine and d-amphetamine.

    PubMed

    Ricaurte, G A; Fuller, R W; Perry, K W; Seiden, L S; Schuster, C R

    1983-10-01

    Repeated administration of large doses of d-methamphetamine produce long-lasting depletion of brain dopamine (DA) and serotonin (5-HT), as well as persistent decreases in the activity of their respective biosynthetic enzymes, tyrosine hydroxylase (TH) and tryptophan hydroxylase (TPH). The present results indicate that the inhibitor of 5-HT uptake fluoxetine, prevented the long-term depletion of 5-HT produced by large doses of methamphetamine (15 mg/kg X 5, 6 hr apart) in the neostriatum and hippocampus, while simultaneously augmenting the depletion of DA produced by this drug in the neostriatum. Fluoxetine also enhanced the prolonged neostriatal depletion of DA produced by a comparable regimen of d-amphetamine. In these doses (15 mg/kg X 5,6 hr apart), d-amphetamine did not produce long-lasting depletion of 5-HT in either the neostriatum or hippocampus. Larger depletion of DA after the amphetamines had been administered in the fluoxetine pretreated animal were associated with a transient increase in the brain levels of methamphetamine and amphetamine. This suggests that fluoxetine may inhibit the metabolism of amphetamines. PMID:6606137

  3. Effect of acute brain tyrosine depletion on MDMA-induced changes in brain 5-HT.

    PubMed

    Rodsiri, R; Green, A R; Marsden, C A; Fone, K C F

    2010-02-01

    The mechanism by which 3,4-methylenedioxymethamphetamine (MDMA) produces 5-hydroxytryptamine (5-HT, serotonin) neurotoxicity has been suggested to involve an acute release of tyrosine and its non-enzymatic conversion to dopamine. To determine whether brain tyrosine availability is important in MDMA-induced neurotoxicity, brain tyrosine was acutely depleted with a tyrosine-free amino acid mixture (1 g/kg intraperitoneal; twice 1 h apart) which was administered prior to an injection of MDMA (12.5 mg/kg intraperitoneal). A small increase in both the hippocampal and striatal tyrosine concentration occurred in control rats treated with MDMA. The tyrosine-free amino acid mixture significantly decreased tyrosine levels by more than 50% in both brain regions 2 h after injection of either MDMA or saline. MDMA significantly reduced brain 5-HT content 2 h later, but this was of a similar magnitude in control and tyrosine-depleted groups. The long-term neurotoxic 5-HT loss in the hippocampus induced two weeks after MDMA administration was unaltered by the tyrosine-free amino acid mixture. Striatal dopamine content was unaffected by acute MDMA in all groups, while the tyrosine-free amino acid mixture given with MDMA significantly decreased striatal dopamine content 2 weeks later. The tyrosine-free amino acid mixture given alone had no affect on rectal body temperature but attenuated the duration of MDMA-induced hyperthermia. The results confirmed the ability of systemic MDMA to acutely increase brain tyrosine content, but also indicated that a marked acute reduction of brain tyrosine does not directly affect either immediate 5-HT release (as measured by tissue depletion) or long-term hippocampal serotonergic neurotoxicity produced by MDMA. PMID:19965941

  4. Nifedipine prevents iron accumulation and reverses iron-overload-induced dopamine neuron degeneration in the substantia nigra of rats.

    PubMed

    Ma, ZeGang; Zhou, Yu; Xie, JunXia

    2012-11-01

    The mechanisms of iron accumulation in substantia nigra (SN) of Parkinson's diseases remain unclear. The objective of this study was to investigate effects of nifedipine on iron-overload-induced iron accumulation and neurodegeneration in SN of rats. By high performance liquid chromatography-electrochemical detection, tyrosine hydroxylase (TH) immunohistochemistry, and iron content array, we first quantified iron content and the number of dopamine neurons in SN of experimental rats treated with iron dextran. We further assessed effects of treatment with nifedipine. Our results showed that nifedipine treatment prevents iron dextran-induced dopamine depletion in the striatum. Consistently, we found that nifedipine restores the number of TH-positive neurons reduced by iron dextran overload and prevents increase of iron content in the SN. These results suggested that nifedipine may suppress iron toxicity in dopamine neurons and prevent neurodegeneration. PMID:22259026

  5. Hypoinsulinemia Regulates Amphetamine-Induced Reverse Transport of Dopamine

    PubMed Central

    Williams, Jason M; Owens, W. Anthony; Turner, Gregory H; Saunders, Christine; Dipace, Concetta; Blakely, Randy D; France, Charles P; Gore, John C; Daws, Lynette C; Avison, Malcolm J; Galli, Aurelio

    2007-01-01

    The behavioral effects of psychomotor stimulants such as amphetamine (AMPH) arise from their ability to elicit increases in extracellular dopamine (DA). These AMPH-induced increases are achieved by DA transporter (DAT)-mediated transmitter efflux. Recently, we have shown that AMPH self-administration is reduced in rats that have been depleted of insulin with the diabetogenic agent streptozotocin (STZ). In vitro studies suggest that hypoinsulinemia may regulate the actions of AMPH by inhibiting the insulin downstream effectors phosphotidylinositol 3-kinase (PI3K) and protein kinase B (PKB, or Akt), which we have previously shown are able to fine-tune DAT cell-surface expression. Here, we demonstrate that striatal Akt function, as well as DAT cell-surface expression, are significantly reduced by STZ. In addition, our data show that the release of DA, determined by high-speed chronoamperometry (HSCA) in the striatum, in response to AMPH, is severely impaired in these insulin-deficient rats. Importantly, selective inhibition of PI3K with LY294002 within the striatum results in a profound reduction in the subsequent potential for AMPH to evoke DA efflux. Consistent with our biochemical and in vivo electrochemical data, findings from functional magnetic resonance imaging experiments reveal that the ability of AMPH to elicit positive blood oxygen leveldependent signal changes in the striatum is significantly blunted in STZ-treated rats. Finally, local infusion of insulin into the striatum of STZ-treated animals significantly recovers the ability of AMPH to stimulate DA release as measured by high-speed chronoamperometry. The present studies establish that PI3K signaling regulates the neurochemical actions of AMPH-like psychomotor stimulants. These data suggest that insulin signaling pathways may represent a novel mechanism for regulating DA transmission, one which may be targeted for the treatment of AMPH abuse and potentially other dopaminergic disorders. PMID:17941718

  6. Impaired acquisition of skilled behavior in rotarod task by moderate depletion of striatal dopamine in a pre-symptomatic stage model of Parkinson's disease.

    PubMed

    Ogura, Taichi; Ogata, Masanori; Akita, Hisanao; Jitsuki, Susumu; Akiba, Lisa; Noda, Kazuko; Hoka, Sumio; Saji, Makoto

    2005-03-01

    In view of recent findings that suggest that the nigrostriatal dopamine (DA) system plays a role in motor control and the acquisition of habits and skills, we hypothesized that the striatum-based function underlying the acquisition of skilled behaviors might be more vulnerable to dopamine depletion than the motor control. To test this hypothesis, we investigated whether impaired acquisition of skilled behaviors occurs in a pre-symptomatic stage model of Parkinson's disease (PD). By using the microdialysis method and the 6-OHDA-technique to destroy dopamine neurons, we confirmed that rats with unilateral partial lesions of the nigral dopamine cells by 6-OHDA are suitable for a pre-symptomatic stage model of Parkinson's disease. The rats in this model exhibited moderate disruption of striatal dopamine release function and relatively intact motor functions. In a rotarod test, the impaired acquisition of skilled behavior occurred in rats with bilateral partial lesions of the nigral dopamine cells by 6-OHDA. These rats displayed intact general motor functions, such as locomotor activity, adjusting steps, equilibrium function and muscle strength. Based on these results, we concluded that the striatum-based function underlying the acquisition of skilled behaviors or sensorimotor learning may be more vulnerable to dopamine depletion than the motor control. PMID:15710494

  7. Fluoxetine Administration Exacerbates Oral Tremor and Striatal Dopamine Depletion in a Rodent Pharmacological Model of Parkinsonism.

    PubMed

    Podurgiel, Samantha J; Milligan, Meredith N; Yohn, Samantha E; Purcell, Laura J; Contreras-Mora, Hector M; Correa, Merc; Salamone, John D

    2015-08-01

    The cardinal motor symptoms of Parkinson's disease (PD) include resting tremor, akinesia, bradykinesia, and rigidity, and these motor abnormalities can be modeled in rodents by administration of the VMAT-2 (type-2 vesicular monoamine transporter) inhibitor tetrabenazine (9,10-dimethoxy-3-(2-methylpropyl)-1,3,4,6,7, 11b hexahydrobenzo[a]quinolizin-2-one; TBZ). Depression is also commonly associated with PD, and clinical data indicate that selective serotonin reuptake inhibitors (SSRIs) such as fluoxetine (()-N-methyl-?-[4-(trifluoromethyl)phenoxy]benzenepropanamine hydrochloride; FLX) are frequently used to treat depression in PD patients. The aim of the present study was to characterize the effect of FLX on the motor dysfunctions induced by a low dose of TBZ (0.75 mg/kg), and investigate the neural mechanisms involved. This low dose of TBZ was selected based on studies with rat models of depressive symptoms. In rats, coadministration of FLX (2.5, 5.0, and 10.0 mg/kg) increased TBZ-induced oral tremor (tremulous jaw movements), and decreased locomotor activity compared with administration of TBZ alone. Coadministration of the serotonin 5-HT2A/2C antagonist mianserin (2.5 and 5.0 mg/kg) attenuated the increase in oral tremor induced by coadministration of TBZ (0.75 mg/kg) with FLX (5.0 mg/kg). Consistent with these behavioral data, coadministration of TBZ and FLX decreased DA tissue levels in the rat ventrolateral neostriatum compared with TBZ alone, and coadministration of mianserin with TBZ and FLX attenuated this effect, increasing DA tissue levels compared with the TBZ/FLX condition. These data suggest that SSRI administration in PD patients may result in worsening of motor symptoms, at least in part, by exacerbating existing DA depletions through 5-HT2A/2C-mediated modulation of DA neurotransmission. PMID:25759301

  8. METHAMPHETAMINE-INDUCED DOPAMINE TERMINAL DEFICITS IN THE NUCLEUS ACCUMBENS ARE EXACERBATED BY REWARD-ASSOCIATED CUES AND ATTENUATED BY CB1 RECEPTOR ANTAGONISM

    PubMed Central

    Loewinger, Gabriel C.; Beckert, Michael V.; Tejeda, Hugo A.; Cheer, Joseph F.

    2012-01-01

    Methamphetamine (METH) exposure is primarily associated with deleterious effects to dopaminergic neurons. While several studies have implicated the endocannabinoid system in METH’s locomotor, rewarding and neurochemical effects, a role for this signaling system in METH’s effects on dopamine terminal dynamics has not been elucidated. Given that CB1 receptor blockade reduces the acute potentiation of phasic extracellular dopamine release from other psychomotor stimulant drugs and that the degree of acute METH-induced increases in extracellular dopamine levels is related to the severity of dopamine depletion, we predicted that pretreatment with the CB1 receptor antagonist rimonabant would reduce METH-induced alterations at dopamine terminals. Furthermore, we hypothesized that administration of METH in environments where reward associated-cues were present would potentiate METH’s acute effects on dopamine release in the nucleus accumbens and exacerbate changes in dopamine terminal activity. Fast-scan cyclic voltammetry was used to measure electrically-evoked dopamine release in the nucleus accumbens and revealed markers of compromised dopamine terminal integrity nine days after a single dose of METH. These were exacerbated in animals that received METH in the presence of reward-associated cues, and attenuated in rimonabant-pretreated animals. While these deficits in dopamine dynamics were associated with reduced operant responding on days following METH administration in animals treated with only METH, rimonabant-pretreated animals exhibited levels of operant responding comparable to control. Moreover, dopamine release correlated significantly with changes in lever pressing behavior that occurred on days following METH administration. Together these data suggest that the endocannabinoid system is involved in the subsecond dopaminergic response to METH. PMID:22306525

  9. Neurochemical correlates of sparing from motor deficits in rats depleted of striatal dopamine as weanlings.

    PubMed

    Sandstrom, Michael I; Nelson, Christopher L; Bruno, John P

    2003-12-01

    The behavioral and neurochemical effects of striatal DA depletions were investigated in rats lesioned as weanlings (Day 27) or as adults (250-300 g). Administration of 6-OHDA into the medial forebrain bundle resulted in comparably large (> or = 95%) depletions of tissue levels of DA in both age groups. As expected, rats depleted of DA as adults exhibited marked deficits in motoric behavior and body weight regulation that persisted for the 8 days of postsurgical observation. In contrast, rats depleted of DA as weanlings were spared from such deficits, and their behavior closely resembled that of age-matched controls. Microdialysis studies revealed dialysate levels of striatal DA that paralleled these age-dependent behavioral differences. At a time when age-related behavioral differences were still quite pronounced (5-6 days postsurgery), basal DA levels were reduced by 80% of control values in rats lesioned as adults whereas basal DA levels in rats lesioned as weanlings were unchanged relative to their controls. Finally, adults depleted of striatal DA as weanlings were no more sensitive to the movement-impairing effects of intrastriatal sulpiride (3.0 or 10.0 micrograms/hemisphere) infusions than were control rats. These data suggest that weanlings compensate for large, but incomplete, denervation of striatal DA with markedly enhanced release and turnover from residual terminals. This developmental plasticity may prevent the occurrence of behavioral deficits soon after the lesion and also the supersensitivity to the challenging effects of DA antagonists as animals grow into adulthood. PMID:15027421

  10. Overexpression of the dopamine D3 receptor in the rat dorsal striatum induces dyskinetic behaviors.

    PubMed

    Cote, Samantha R; Chitravanshi, Vineet C; Bleickardt, Carina; Sapru, Hreday N; Kuzhikandathil, Eldo V

    2014-04-15

    L-DOPA-induced dyskinesias (LID) are motor side effects associated with treatment of Parkinson's disease (PD). The etiology of LID is not clear; however, studies have shown that the dopamine D3 receptor is upregulated in the basal ganglia of mice, rats and non-human primate models of LID. It is not known if the upregulation of D3 receptor is a cause or result of LID. In this paper we tested the hypothesis that overexpression of the dopamine D3 receptor in dorsal striatum, in the absence of dopamine depletion, will elicit LID. Replication-deficient recombinant adeno-associated virus-2 expressing the D3 receptor or enhanced green fluorescent protein (EGFP) were stereotaxically injected, unilaterally, into the dorsal striatum of adult rats. Post-hoc immunohistochemical analysis revealed that ectopic expression of the D3 receptor was limited to neurons near the injection sites in the dorsal striatum. Following a 3-week recovery period, rats were administered saline, 6 mg/kg L-DOPA, 0.1 mg/kg PD128907 or 10 mg/kg ES609, i.p., and motor behaviors scored. Rats overexpressing the D3 receptor specifically exhibited contralateral axial abnormal involuntary movements (AIMs) following administration of L-DOPA and PD128907 but not saline or the novel agonist ES609. Daily injection of 6 mg/kg L-DOPA to the rats overexpressing the D3 receptor also caused increased vacuous chewing behavior. These results suggest that overexpression of the D3 receptor in the dorsal striatum results in the acute expression of agonist-induced axial AIMs and chronic L-DOPA-induced vacuous chewing behavior. Agonists such as ES609 might provide a novel therapeutic approach to treat dyskinesia. PMID:24462727

  11. Dopamine depletion affects communicative intentionality in Parkinson's disease patients: Evidence from action kinematics.

    PubMed

    Straulino, Elisa; Scaravilli, Tomaso; Castiello, Umberto

    2016-04-01

    Appropriate communication is at the heart of successful, healthy social interactions in humans. Deficits in social communication are a hallmark of several neurological and psychiatric disorders. Yet, very little research has been devoted to understanding the mechanisms underlying these issues. It has been suggested that dopamine is a candidate neurotransmitter system involved in stimulating communication in individuals that are not highly motivated to communicate. A typical model to study dopaminergic dysfunctions in humans is represented by Parkinson's disease (PD) patients, who show motor, cognitive and motivational symptoms. Our study aimed to investigate the effects of social communication on actions in non-demented PD patients receiving dopamine replacement therapy (Levodopa = l-Dopa) and in neurologically healthy control participants. Patients' ability to modulate motor patterning depending on the communicative intention motivating the action to be performed was evaluated both in "on" (with l-Dopa) and "off" (without l-Dopa) states. In two main conditions, participants were requested to reach towards, grasp an object, and either simply lift it (individual condition) or lift it with the intent to communicate a meaning to a partner (communicative condition). Movements' kinematics was recorded using a three-dimensional motion analysis system. The results indicate that kinematics is sensitive to communicative intention and that l-Dopa treatment has positive effects on translating communicative intentions into specific motor patterns in PD patients. Although the to-be-grasped object remained the same both the controls and the PD patients in an 'on' state adopted different kinematic patterning for the 'individual' and the 'communication' conditions. The PD patients in the 'off' state, instead, were unable to kinematically differentiate between the two conditions. We contend that social and communicative impairments are associated with abnormalities in dopaminergic pathways. PMID:26922506

  12. 2-Chloroacetaldehyde-induced cerebral glutathione depletion and neurotoxicity.

    PubMed Central

    Sood, C.; O'Brien, P. J.

    1996-01-01

    2-Chloroacetaldehyde (CAA) formed during the metabolism of the anti-cancer drug ifosfamide (IP) has been implicated in ifosfamide-related neurotoxicity during chemotherapy but the neurotoxic mechanisms are unknown. We have found that IP (900 mg kg-1, p.o.) caused lethargy and mild hind limb paralysis after 6 h. Neurotoxicity and IP-induced mortality was markedly enhanced in mice pretreated with either phenobarbital or dexamethasone to induce cytochrome P4503A. Cerebral glutathione (GSH) levels were also markedly depleted in these pretreated mice. 2-Chloroethanol (92 mg kg-1, i.p.) (CE) also caused a 50% reduction in cerebral GSH 6 h after administration to mice. At this time maximum lethargy and unresponsiveness to touch was apparent in CE-treated mice. Severe hind limb paralysis developed and death ensued 12-18 h later. Prior depletion of cerebral GSH with 2-cyclohexene-1-one greatly accelerated the onset of CE-induced neurotoxicity suggesting that cerebral GSH status is an important determinant of CE-induced neurotoxicity. Furthermore, pretreatment with N-acetylcysteine delayed both CE-induced neurotoxicity and cerebral GSH depletion. Induction of cerebral but not hepatic CYP2E1 by ethanol before CE challenge also potentiated CE-induced cerebral GSH depletion and neurotoxicity. Hepatic GSH depletion was unaffected suggesting that CE-induced paralysis is dependent on a cerebral but not a hepatic CYP2E1 catalysed oxidation of CE to CAA. Ethanol was neuroprotective even if given 60 min after CE and prevented further cerebral GSH depletion. 4-Methylpyrazole, a CYP2E1 and alcohol dehydrogenase inhibitor, prevented both CE-induced hepatic and cerebral GSH depletion and paralysis. This suggests that the neurotoxicity associated with IP chemotherapy involves activation of chloroethanol by cerebral CYP2E1 to chloroacetaldehyde which mediates cerebral GSH depletion. Neurotoxicity may be prevented by restoring cerebral GSH status and/or by preventing activation of CE by CYP2E1 with ethanol. PMID:8763899

  13. Association of body mass index and the depletion of nigrostriatal dopamine in Parkinson's disease.

    PubMed

    Lee, Jae Jung; Oh, Jungsu S; Ham, Jee H; Lee, Dong H; Lee, Injoo; Sohn, Young H; Kim, Jae S; Lee, Phil Hyu

    2016-02-01

    Several antecedent studies had reported close relationship between low body weight and Parkinson's disease (PD). However, there have been few investigations about the role of body weight to nigrostriatal dopaminergic neurodegeneration. This study enrolled 398 de novo patients with PD whom underwent [(18)F] N-(3-Fluoropropyl)-2β-carbon ethoxy-3β-(4-iodophenyl) nortropane positron emission tomography scan and body mass index (BMI) measurement. The relationships between BMI and dopamine transporter (DAT) activity were analyzed using linear regression analysis. A multivariate analysis adjusted for age, gender, disease duration, smoking status, coffee and tea consumption, and residence area revealed that BMI remained independently and significantly associated with DAT activity in all striatal subregions. Moreover, multiple logistic regression analyses showed that BMI was a significant predictor for the lowest quartile of DAT activity in the anterior putamen, ventral striatum, caudate nucleus, and total striatum. The present findings suggest that a low BMI might be closely associated with low density of nigrostriatal dopaminergic neurons in PD, which could support the evidence for the role of low body weight to PD-related pathologies. PMID:26827658

  14. Reduced vocal variability in a zebra finch model of dopamine depletion: implications for Parkinson disease.

    PubMed

    Miller, Julie E; Hafzalla, George W; Burkett, Zachary D; Fox, Cynthia M; White, Stephanie A

    2015-11-01

    Midbrain dopamine (DA) modulates the activity of basal ganglia circuitry important for motor control in a variety of species. In songbirds, DA underlies motivational behavior including reproductive drive and is implicated as a gatekeeper for neural activity governing vocal variability. In the zebra finch, Taeniopygia guttata, DA levels increase in Area X, a song-dedicated subregion of the basal ganglia, when a male bird sings his courtship song to a female (female-directed; FD). Levels remain stable when he sings a less stereotyped version that is not directed toward a conspecific (undirected; UD). Here, we used a mild dose of the neurotoxin 6-hydroxydopamine (6-OHDA) to reduce presynaptic DA input to Area X and characterized the effects on FD and UD behaviors. Immunoblots were used to quantify levels of tyrosine hydroxylase (TH) as a biomarker for DA afferent loss in vehicle- and 6-OHDA-injected birds. Following 6-OHDA administration, TH signals were lower in Area X but not in an adjacent subregion, ventral striatal-pallidum (VSP). A postsynaptic marker of DA signaling was unchanged in both regions. These observations suggest that effects were specific to presynaptic afferents of vocal basal ganglia. Concurrently, vocal variability was reduced during UD but not FD song. Similar decreases in vocal variability are observed in patients with Parkinson disease (PD), but the link to DA loss is not well-understood. The 6-OHDA songbird model offers a unique opportunity to further examine how DA loss in cortico-basal ganglia pathways affects vocal control. PMID:26564062

  15. Reduced vocal variability in a zebra finch model of dopamine depletion: implications for Parkinson disease

    PubMed Central

    Miller, Julie E; Hafzalla, George W; Burkett, Zachary D; Fox, Cynthia M; White, Stephanie A

    2015-01-01

    Midbrain dopamine (DA) modulates the activity of basal ganglia circuitry important for motor control in a variety of species. In songbirds, DA underlies motivational behavior including reproductive drive and is implicated as a gatekeeper for neural activity governing vocal variability. In the zebra finch, Taeniopygia guttata, DA levels increase in Area X, a song-dedicated subregion of the basal ganglia, when a male bird sings his courtship song to a female (female-directed; FD). Levels remain stable when he sings a less stereotyped version that is not directed toward a conspecific (undirected; UD). Here, we used a mild dose of the neurotoxin 6-hydroxydopamine (6-OHDA) to reduce presynaptic DA input to Area X and characterized the effects on FD and UD behaviors. Immunoblots were used to quantify levels of tyrosine hydroxylase (TH) as a biomarker for DA afferent loss in vehicle- and 6-OHDA-injected birds. Following 6-OHDA administration, TH signals were lower in Area X but not in an adjacent subregion, ventral striatal-pallidum (VSP). A postsynaptic marker of DA signaling was unchanged in both regions. These observations suggest that effects were specific to presynaptic afferents of vocal basal ganglia. Concurrently, vocal variability was reduced during UD but not FD song. Similar decreases in vocal variability are observed in patients with Parkinson disease (PD), but the link to DA loss is not well-understood. The 6-OHDA songbird model offers a unique opportunity to further examine how DA loss in cortico-basal ganglia pathways affects vocal control. PMID:26564062

  16. Methamphetamine-induced dopamine and serotonin reductions in neostriatum are not gender specific in rats with comparable hyperthermic responses.

    PubMed

    Fukumura, M; Cappon, G D; Broening, H W; Vorhees, C V

    1998-01-01

    Methamphetamine (MA)-induced monoamine depletions in male and female Sprague-Dawley CD rats were studied under conditions in which the magnitude of MA-induced hyperthermia was comparable between the sexes. MA (5 or 10 mg/kg) or saline (3 ml/kg) was administered SC four times at 2-h intervals. Animals were sacrificed 3 days posttreatment for the determination of dopamine (DA), serotonin (5-HT), and metabolites. MA induced significant monoamine reductions but the magnitude of these reductions was not significantly different between males and females. In the MA 5 mg/kg groups, neostriatal DA content was reduced by 51.2% and 44.8%, whereas 5-HT content was reduced by 30.6% and 23.9% of controls for males and females, respectively. In the MA 10 mg/kg groups, neostriatal DA content was reduced by 72.9% and 65.8%, whereas striatal 5-HT content was reduced by 77.4% and 73.6% of controls for males and females, respectively. No significant differences in thermal responses to MA were observed between genders. Unlike reports in mice, gender does not play a role in MA-induced monoamine reductions in rat neostriatum when MA-induced hyperthermia is comparable across sexes. The data also showed a threshold effect in which dopamine depletions were not correlated with hyperthermia at core body temperatures above approximately 41 degrees C. PMID:9697970

  17. The Effects of Acute Dopamine Precursor Depletion on the Cognitive Control Functions of Performance Monitoring and Conflict Processing: An Event-Related Potential (ERP) Study

    PubMed Central

    Primosch, Mark; Leyton, Marco; Steffensen, Scott C.

    2015-01-01

    Studies using medications and psychiatric populations implicate dopamine in cognitive control and performance monitoring processes. However, side effects associated with medication or studying psychiatric groups may confound the relationship between dopamine and cognitive control. To circumvent such possibilities, we utilized a randomized, double-blind, placebo-controlled, within-subjects design wherein participants were administered a nutritionally-balanced amino acid mixture (BAL) and an amino acid mixture deficient in the dopamine precursors tyrosine (TYR) and phenylalanine (PHE) on two separate occasions. Order of sessions was randomly assigned. Cognitive control and performance monitoring were assessed using response times (RT), error rates, the N450, an event-related potential (ERP) index of conflict monitoring, the conflict slow potential (conflict SP), an ERP index of conflict resolution, and the error-related negativity (ERN) and error positivity (Pe), ERPs associated with performance monitoring. Participants were twelve males who completed a Stroop color-word task while ERPs were collected four hours following acute PHE and TYR depletion (APTD) or balanced (BAL) mixture ingestion in two separate sessions. N450 and conflict SP ERP amplitudes significantly differentiated congruent from incongruent trials, but did not differ as a function of APTD or BAL mixture ingestion. Similarly, ERN and Pe amplitudes showed significant differences between error and correct trials that were not different between APTD and BAL conditions. Findings indicate that acute dopamine precursor depletion does not significantly alter cognitive control and performance monitoring ERPs. Current results do not preclude the role of dopamine in these processes, but suggest that multiple methods for dopamine-related hypothesis testing are needed. PMID:26492082

  18. Nicotine Decreases Ethanol-induced Dopamine Signaling and Increases Self-administration via Stress Hormones

    PubMed Central

    Doyon, William M.; Dong, Yu; Ostroumov, Alexey; Thomas, Alyse M.; Zhang, Tao A.; Dani, John A.

    2013-01-01

    SUMMARY Tobacco smoking is a well-known risk factor for subsequent alcohol abuse, but the neural events underlying this risk remain largely unknown. Alcohol and nicotine reinforcement involve common neural circuitry, including the mesolimbic dopamine system. We demonstrate in rodents that pre-exposure to nicotine increases alcohol self-administration and decreases alcohol-induced dopamine responses. The blunted dopamine response was due to increased inhibitory synaptic transmission onto dopamine neurons. Blocking stress hormone receptors prior to nicotine exposure prevented all interactions with alcohol that we measured, including the increased inhibition onto dopamine neurons, the decreased dopamine responses, and the increased alcohol self-administration. These results indicate that nicotine recruits neuroendocrine systems to influence neurotransmission and behavior associated with alcohol reinforcement. PMID:23871233

  19. Depletion-induced structure and dynamics in bimodal colloidal suspensions.

    SciTech Connect

    Sikorski, M.; Sandy, A. R.; Narayanan, S.

    2011-05-03

    Combined small angle x-ray scattering and x-ray photon correlation spectroscopy studies of moderately concentrated bimodal hard-sphere colloidal suspensions in the fluid phase show that depletion-induced demixing introduces spatially heterogeneous dynamics with two distinct time scales. The adhesive nature, as well as the mobility, of the large particles is determined by the level of interaction within the monomodal domains. This interaction is driven by osmotic forces, which are governed by the relative concentration of the constituents.

  20. Alcohol-induced alterations in dopamine modulation of prefrontal activity.

    PubMed

    Trantham-Davidson, Heather; Chandler, L Judson

    2015-12-01

    Long-term alcohol use leads to persistent cognitive deficits that may be associated with maladaptive changes in the neurocircuitry that mediates executive functions. Impairments caused by these changes can persist well into abstinence and have a negative impact on quality of life and job performance, and can increase the probability of relapse. Many of the changes that affect cognitive function appear to involve dysregulation of the mesocortical dopamine system. This includes changes in dopamine release and alterations in dopamine receptor expression and function in the medial prefrontal cortex (PFC). This review summarizes the cellular effects of acute and chronic ethanol exposure on dopamine release and dopamine receptor function in the PFC with the goal of providing greater understanding of the effects of alcohol-use disorders on the dopamine system and how this relates to deficits in the executive function of the PFC. PMID:26558348

  1. An acute, epitope-specific modification in the dopamine transporter associated with methamphetamine-induced neurotoxicity.

    PubMed

    Fricks-Gleason, Ashley N; German, Christopher L; Hoonakker, Amanda J; Friend, Danielle M; Ganesh, Kamala K; Carver, Aaron S; Hanson, Glen R; Fleckenstein, Annette E; Keefe, Kristen A

    2016-04-01

    Preclinical studies demonstrate that repeated, high-dose methamphetamine administrations rapidly decrease plasmalemmal dopamine uptake, which may contribute to aberrant dopamine accumulation, reactive species generation, and long-term dopaminergic deficits. The present study extends these findings by demonstrating a heretofore unreported, epitope-specific modification in the dopamine transporter caused by a methamphetamine regimen that induces these deficits. Specifically, repeated, high-dose methamphetamine injections (4 × 10 mg/kg/injection, 2-h intervals) rapidly decreased immunohistochemical detection of striatal dopamine transporter as assessed 1 h after the final methamphetamine exposure. In contrast, neither a single high dose (1 × 10 mg/kg) nor repeated injections of a lower dose (4 × 2 mg/kg/injection) induced this change. The high-dose regimen-induced alteration was only detected using antibodies directed against the N-terminus. Immunohistochemical staining using antibodies directed against the C-terminus did not reveal any changes. The high-dose regimen also did not alter dopamine transporter expression as assessed using [(125) I]RTI-55 autoradiography. These data suggest that the repeated, high-dose methamphetamine regimen alters the N-terminus of the dopamine transporter. Further, these data may be predictive of persistent dopamine deficits caused by the stimulant. Future studies of the signaling cascades involved should provide novel insight into potential mechanisms underlying the physiological and pathophysiological regulation of the dopamine transporter. Synapse, 2016. © 2016 Wiley Periodicals, Inc. Synapse 70:139-146, 2016. © 2016 Wiley Periodicals, Inc. PMID:26799527

  2. Relationship between cocaine-induced subjective effects and dopamine transporter occupancy

    SciTech Connect

    Volkow, N.D.; Fischman, M.; Wang, G.J.

    1997-05-01

    The ability of cocaine to occupy the dopamine transporter has been linked to its reinforcing properties. However, such a relationship has not been demonstrated in humans. Methods: Positron Emission Tomography and [C-11]cocaine were used to estimate dopamine transporter occupancies after different doses of cocaine in 18 active cocaine abusers. The ratio of the distribution volume of [C-11]cocaine in striatum to that in cerebellum, which corresponds to Bmax/Kd +1 and is insensitive to changes in cerebral blood flow, was our measure of dopamine transporter availability. In parallel subjective effects were measured to assess the relationship between dopamine transporter occupancy and cocaines behavioral effects. Intravenous cocaine produced a significant dose,-dependent blockade of dopamine transporters: 73 % for 0.6 mg/kg; 601/6 for 0.3 mg/kg; 48 % for 0.1 mg/kg iv and 40 % for 0.05 mg/kg. In addition, dopamine transporter occupancies were significantly correlated with cocaine plasma concentration (r = 0.55 p < 0.001). Cocaine also produced dose-dependent increases in self-reported ratings of {open_quotes}high{close_quotes} which were significantly correlated with the levels of dopamine transporter blockade. Discussion: These results provide the first documentation in humans that dopamine transporter occupancy is associated with cocaine induced subjective effects. They also suggest that dopamine transporter occupancies equal to or greater than 60% are required to produce significant effects on ratings of {open_quotes}high{close_quotes}.

  3. Frost Induces Respiration and Accelerates Carbon Depletion in Trees

    PubMed Central

    Sperling, Or; Earles, J. Mason; Secchi, Francesca; Godfrey, Jessie; Zwieniecki, Maciej A.

    2015-01-01

    Cellular respiration depletes stored carbohydrates during extended periods of limited photosynthesis, e.g. winter dormancy or drought. As respiration rate is largely a function of temperature, the thermal conditions during such periods may affect non-structural carbohydrate (NSC) availability and, ultimately, recovery. Here, we surveyed stem responses to temperature changes in 15 woody species. For two species with divergent respirational response to frost, P. integerrima and P. trichocarpa, we also examined corresponding changes in NSC levels. Finally, we simulated respiration-induced NSC depletion using historical temperature data for the western US. We report a novel finding that tree stems significantly increase respiration in response to near freezing temperatures. We observed this excess respiration in 13 of 15 species, deviating 10% to 170% over values predicted by the Arrhenius equation. Excess respiration persisted at temperatures above 0°C during warming and reoccurred over multiple frost-warming cycles. A large adjustment of NSCs accompanied excess respiration in P. integerrima, whereas P. trichocarpa neither excessively respired nor adjusted NSCs. Over the course of the years included in our model, frost-induced respiration accelerated stem NSC consumption by 8.4 mg (glucose eq.) cm-3 yr-1 on average in the western US, a level of depletion that may continue to significantly affect spring NSC availability. This novel finding revises the current paradigm of low temperature respiration kinetics. PMID:26629819

  4. Frost Induces Respiration and Accelerates Carbon Depletion in Trees.

    PubMed

    Sperling, Or; Earles, J Mason; Secchi, Francesca; Godfrey, Jessie; Zwieniecki, Maciej A

    2015-01-01

    Cellular respiration depletes stored carbohydrates during extended periods of limited photosynthesis, e.g. winter dormancy or drought. As respiration rate is largely a function of temperature, the thermal conditions during such periods may affect non-structural carbohydrate (NSC) availability and, ultimately, recovery. Here, we surveyed stem responses to temperature changes in 15 woody species. For two species with divergent respirational response to frost, P. integerrima and P. trichocarpa, we also examined corresponding changes in NSC levels. Finally, we simulated respiration-induced NSC depletion using historical temperature data for the western US. We report a novel finding that tree stems significantly increase respiration in response to near freezing temperatures. We observed this excess respiration in 13 of 15 species, deviating 10% to 170% over values predicted by the Arrhenius equation. Excess respiration persisted at temperatures above 0C during warming and reoccurred over multiple frost-warming cycles. A large adjustment of NSCs accompanied excess respiration in P. integerrima, whereas P. trichocarpa neither excessively respired nor adjusted NSCs. Over the course of the years included in our model, frost-induced respiration accelerated stem NSC consumption by 8.4 mg (glucose eq.) cm-3 yr-1 on average in the western US, a level of depletion that may continue to significantly affect spring NSC availability. This novel finding revises the current paradigm of low temperature respiration kinetics. PMID:26629819

  5. Trans-synaptic (GABA-dopamine) modulation of cocaine induced dopamine release: A potential therapeutic strategy for cocaine abuse

    SciTech Connect

    Dewey, S.L.; Straughter-Moore, R.; Chen, R.

    1995-05-01

    We recently developed a new experimental strategy for measuring interactions between functionally-linked neurotransmitter systems in the primate and human brain with PET. As part of this research, we demonstrated that increases in endogenous GABA concentrations significantly reduced striatal dopamine concentrations in the primate brain. We report here the application of the neurotransmitter interaction paradigm with PET and with microdialysis to the investigation of a novel therapeutic strategy for treating cocaine abuse based on the ability of GABA to inhibit cocaine induced increases in striatal dopamine. Using gamma-vinyl GABA (GVG, a suicide inhibitor of GABA transaminase), we performed a series of PET studies where animals received a baseline PET scan with labeled raclopride injection, animals received cocaine (2.0 mg/kg). Normally, a cocaine challenge significantly reduces the striatal binding of {sup 11}C-raclopride. However, in animals pretreated with GVG, {sup 11}C-raclopride binding was less affected by a cocaine challenge compared to control studies. Furthermore, microdialysis studies in freely moving rats demonstrate that GVG (300 mg/kg) significantly inhibited cocaine-induced increases in extracellular dopamine release. GVG also attenuated cocaine-induced increases in locomotor activity. However, at a dose of 100 mg/kg, GVG had no effect. Similar findings were obtained with alcohol. Alcohol pretreatment dose dependantly (1-4 g/kg) inhibited cocaine-induced increases in extracellular dopamine concentrations in freely moving rats. Taken together, these studies suggest that therapeutic strategies targeted at increasing central GABA concentrations may be beneficial for the treatment of cocaine abuse.

  6. Influence of tacrine on dopamine-induced reactions of the gastric smooth muscle of rats.

    PubMed

    Turijski, V; Krustev, A; Getova-Spassova, D; Spassov, V

    2004-03-01

    The clinical usage of the cholinesterase inhibitor tacrine for treatment of Alzheimer's disease is accompanied by adverse effects on the gastrointestinal tract. These adverse effects are a result of the direct action of tacrine on the intestinal smooth muscles or of the modulation of certain neurotransmitters regulating gastrointestinal functions. Dopamine is a neurotransmitter that modulates gastrointestinal motility. This study was designed to examine in vitro the effects of tacrine on dopamine-induced changes in spontaneous activity of smooth muscle preparations from rat's gastric corpus. The mechanical activity was isometrically registered. Tacrine 1.10(-7)-1.10(-5) mol/l caused smooth muscle contraction, which was blocked by atropine 1.10(-6) mol/l. Tacrine 1.10(-4) mol/l provoked a relaxation resistant to atropine. Dopamine and D(2)-receptor antagonists haloperidol and R121 had no effect on tacrine-induced relaxation. Dopamine-induced contraction was concentration-dependent. It was blocked by D(2)-receptor antagonists haloperidol and R121 and by tacrine 1.10(-4) mol/l. In the presence of tacrine 1.10(-7)-10(-5) mol/l or atropine the dopamine-induced contraction was significant. The data obtained suggested that tacrine 1.10(-4) mol/l inhibited the dopamine effects on gastric corpus smooth muscles. The effect was probably not dependent on its anticholinesterase activity or not realized through direct influence on D(2)-dopamine receptors. PMID:15071608

  7. Can Dopamine Depletion at DAT Scan in a Non Parkinson Patient be the Cause a Refractory Overactive Bladder?

    PubMed Central

    Renard, J.; Citeri, M.; Zanollo, L.; Guerrer, C.; Rizzato, L.; Frediani, L.; Iselin, C.E.; Spinelli, M.

    2015-01-01

    We report here the first case of treatment of idiopathic refractory overactive bladder with dopamine. A female patient consulted for urge incontinence. Management included all recommended treatments without success. DAT scan was finally performed showing clear reduction in dopamine secretion without diagnosis of any neurological condition. Patient started dopamine treatment. At 1month, patient described persistence of mild urgency and frequency but complete resolution of urge incontinence. At3months patient was completely dry with only persistence of mild frequency. Functional imaging and central nervous system target might represent new ways of managingidiopathic overactive bladder.

  8. Dopamine D1-like receptor activation induces brain-derived neurotrophic factor protein expression.

    PubMed

    Williams, Stacey N; Undieh, Ashiwel S

    2009-04-22

    Recent studies showed that dopamine or D1 receptor-selective agonists increased brain-derived neurotrophic factor (BDNF) mRNA and protein expression in neuronal cultures, and this action was blocked by SCH23390. Moreover, SKF38393 activated Trk receptors and downstream signaling in striatal neurons. This study examined whether dopamine agonists induce the expression of BDNF protein in rat brain tissue. Acute slice preparations were incubated with dopamine agonists in Hibernate A medium and BDNF protein was measured by a sensitive enzyme-linked immunosorbent assay. Results showed that dopamine increased BDNF in tissue slices after 24 h of incubation. Furthermore, SKF38393 produced a significant increase in BDNF protein in striatal and hippocampal tissue slices. These findings suggest that the induction of BDNF expression may constitute a downstream response to D1-like dopamine receptor activation. PMID:19295451

  9. Prenatal L-DOPA exposure produces lasting changes in brain dopamine content, cocaine-induced dopamine release and cocaine conditioned place preference.

    PubMed

    Ren, Jia-Qian; Jiang, Yan; Wang, Zhihui; McCarthy, Deirdre; Rajadhyaksha, Anjali M; Tropea, Thomas F; Kosofsky, Barry E; Bhide, Pradeep G

    2011-01-01

    Dopamine, its receptors and transporter are present in the brain beginning from early in the embryonic period. Dopamine receptor activation can influence developmental events including neurogenesis, neuronal migration and differentiation raising the possibility that dopamine imbalance in the fetal brain can alter development of the brain and behavior. We examined whether elevated dopamine levels during gestation can produce persisting changes in brain dopamine content and dopamine-mediated behaviors. We administered L-3,4-dihydroxyphenylalanine (L-DOPA) in drinking water to timed-pregnant CD1 mice from the 11th day of gestation until the day of parturition. The prenatal L-DOPA exposure led to significantly lower cocaine conditioned place preference, a behavioral test of reward, at postnatal day 60 (P60). However, in vivo microdialysis measurements showed significant increases in cocaine-induced dopamine release in the caudate putamen of P26 and P60 mice exposed to L-DOPA prenatally, ruling out attenuated dopamine release in the caudate putamen as a contributor to decreased conditioned place preference. Although dopamine release was induced in the nucleus accumbens of prenatally L-DOPA exposed mice at P60 by cocaine, the dopamine release in the nucleus accumbens was not significantly different between the L-DOPA and control groups. However, basal dopamine release was significantly higher in the prenatally L-DOPA exposed mice at P60 suggesting that the L-DOPA exposed mice may require a higher dose of cocaine for induction of cocaine place preference than the controls. The prenatal L-DOPA exposure did not alter cocaine-induced locomotor response, suggesting dissociation between the effects of prenatal L-DOPA exposure on conditioned place preference and locomotor activity. Tissue concentration of dopamine and its metabolites in the striatum and ventral midbrain were significantly affected by the L-DOPA exposure as well as by developmental changes over the P14-P60 period. Thus, elevation of dopamine levels during gestation can produce persisting changes in brain dopamine content, cocaine-induced dopamine release and cocaine conditioned place preference. PMID:20854831

  10. Mechanisms Underlying Methamphetamine-Induced Dopamine Transporter Complex Formation

    PubMed Central

    Hadlock, Gregory C.; Baucum, Anthony J.; King, Jill L.; Horner, Kristen A.; Cook, Glen A.; Gibb, James W.; Wilkins, Diana G.; Hanson, Glen R.; Fleckenstein, Annette E.

    2009-01-01

    Repeated, high-dose methamphetamine (METH) administrations cause persistent dopaminergic deficits in rodents, nonhuman primates, and humans. In rats, this treatment also causes the formation of high-molecular mass (greater than approximately 120 kDa) dopamine transporter (DAT)-associated complexes, the loss of DAT monomer immunoreactivity, and a decrease in DAT function, as assessed in striatal synaptosomes prepared 24 h after METH treatment. The present study extends these findings by demonstrating the regional selectivity of DAT complex formation and monomer loss because these changes in DAT immunoreactivity were not observed in the nucleus accumbens. Furthermore, DAT complex formation was not a consequence limited to METH treatment because it was also caused by intrastriatal administration of 6-hydroxydopamine. Pretreatment with the D2 receptor antagonist, eticlopride [S-(-)-3-chloro-5-ethyl-N-[(1-ethyl-2-pyrrolidinyl)methyl]-6-hydroxy-2-methoxybenzamide hydrochloride], but not the D1 receptor antagonist, SCH23390 [R(+)-7-chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine hydrochloride], attenuated METH-induced DAT complex formation. Eticlopride pretreatment also attenuated METH-induced DAT monomer loss and decreases in DAT function; however, the attenuation was much less pronounced than the effect on DAT complex formation. Finally, results also revealed a negative correlation between METH-induced DAT complex formation and DAT activity. Taken together, these data further elucidate the underlying mechanisms and the functional consequences of repeated administrations of METH on the DAT protein. Furthermore, these data suggest a multifaceted role for D2 receptors in mediating METH-induced alterations of the DAT and its function. PMID:19141713

  11. A dopamine antagonist blocks vaginocervical stimulation-induced neuronal responses in the rat forebrain.

    PubMed

    Quysner, A; Blaustein, J D

    2001-12-01

    During mating in rats, the male provides vaginocervical stimulation (VCS) to the female via intromissions. VCS, provided manually, mimics many aspects of mating, including facilitation of lordosis, induction of sexual receptivity, abbreviation of the period of sexual receptivity, and induction of twice-daily prolactin surges, which result in pseudopregnancy. VCS also induces the expression of Fos, the protein product of the immediate early gene c-fos, which has been used as a marker for neurons that are responsive to mating stimuli. Because VCS induces the release of dopamine in the forebrain, as well as phosphorylation of DARPP-32, a phosphoprotein associated with activation of the D(1) subtype of dopamine receptor, we tested the hypothesis that VCS induces Fos expression by acting on the D(1) class of dopamine receptors. Injection of SCH 23390, an antagonist of the D(1) class of dopamine receptors, virtually eliminated VCS-induced Fos expression without affecting constitutive levels of Fos-Immunoreactivity (Fos-IR) in all brain areas in which VCS induced Fos expression. In a follow-up experiment, expression of a second immediate early protein, egr-1, was blocked as well, suggesting that these results are not specific to Fos. Therefore, the results are consistent with the idea that VCS induces dopamine release, causing activation of D(1) dopamine receptors, which in turn, results in neuronal response, as seen by both Fos and egr-1 expression. PMID:11720724

  12. Acute alcohol administration improves skilled reaching success in intact but not 6-OHDA dopamine depleted rats: a subsystems analysis of the motoric and anxiolytic effects of alcohol.

    PubMed

    Metz, Gerlinde A; Gonzalez, Claudia L R; Piecharka, Dionne M; Whishaw, Ian Q

    2003-06-16

    Low doses of alcohol impair movement and reduce anxiety. Most assessments of movement under ethyl alcohol (alcohol) in the rat have been tests of whole body movements, however. There has been no examination of the effects of alcohol on skilled limb movements, such as reaching for food with a forelimb. This was the purpose of the present study. Rats were trained to reach through a slot of a box with a forelimb in order to obtain a food pellet located on an external shelf. Once asymptotic performance was achieved, rats were given alcohol (20 ml of 8, 12 or 20% (v/v) solution) in separate tests to establish a relationship between alcohol ingestion and skilled reaching performance. Acute treatment with all doses of alcohol impaired postural support, but doses of 8 and 12% alcohol improved skilled reaching success. Qualitative analysis of the movements used for reaching at doses of 8 and 12% indicated that some limb components of the reaching movement were also impaired, perhaps secondarily due to impaired posture. In contrast, the reaching success of rats with unilateral dopamine depletion, induced with the neurotoxin 6-hydroxydopamine (6-OHDA) in the nigrostriatal bundle, was impaired by the same dose of alcohol that improved reaching success in control rats. The finding of improved success in reaching associated with reduced postural support in normal rats suggests a differential action of alcohol on movement subsystems underlying posture relative to skilled movement that depends upon an intact dopaminergic system. The results are also discussed with respect to the relationship of subsystems of movement and anxiety. PMID:12798278

  13. Characterization of dopamine receptor subtypes involved in experimentally induced gastric and duodenal ulcers in rats.

    PubMed

    Desai, J K; Goyal, R K; Parmar, N S

    1999-02-01

    There are conflicting reports about the role of dopamine in gastric and duodenal ulcers. This investigation was undertaken to characterize the specific subtypes of dopamine receptor involved in gastric and duodenal ulceration. Administration of dopamine D1 agonist fenoldopam and dopamine D2 antagonist sulpiride elicited a significant decrease in acid secretion, total acid output, pepsin output and histamine content in the gastric juice, and reduced ulcer-index values, in pylorus-ligated rats. However, dopamine D1 receptor antagonist SCH 39166 ((-)-trans-6,7,7a,8,9,13b-hexahydro-3-chloro-2-hydroxy-N-methyl-5H -benzo (d) naptho -(2,1-b) azepine) and the D2 receptor agonist quinpirole led to significant augmentation of these parameters compared with respective controls. In the restraint plus water-immersion stress model the score for intraluminal bleeding and the cumulative gastric lesion length was significantly lower for rats treated with fenoldopam and sulpiride. The opposite effects were observed after pretreatment of rats with SCH 39166 and quinpirole. In the cysteamine-induced duodenal ulcer model the mean ulcer area and the score for intensity were significantly lower for fenoldopam and sulpiride and higher for SCH 39166 and quinpirole. Our data suggest that the dopamine D1 and D2 receptors have opposite effects on gastric and duodenal ulcers. Whereas stimulation of dopamine D1 receptors inhibits the formation of gastric and duodenal ulcers, stimulation of dopamine D2 receptors has a pro-ulcerogenic effect. PMID:10217318

  14. Neutrophil depletion inhibits airway hyperresponsiveness induced by ozone exposure

    SciTech Connect

    O'Byrne, P.M.; Walters, E.H.; Gold, B.D.; Aizawa, H.A.; Fabbri, L.M.; Alpert, S.E.; Nadel, J.A.; Holtzman, M.J.

    1984-08-01

    We studied whether ozone-induced hyperresponsiveness could be inhibited by neutrophil depletion in dogs. Responsiveness was assessed with dose-response curves of acetylcholine aerosol versus pulmonary resistance; depletion was assessed by counting neutrophils in venous blood and in biopsies of the airway epithelium. Responsiveness and neutrophil numbers were determined 5 days and 1 day before ozone and 1 h after ozone (3.0 ppm, 2 h) in 6 untreated dogs and in 6 dogs treated with hydroxyurea (200 mg/kg daily for 5 days starting 5 days before ozone). In untreated dogs, responsiveness and neutrophil numbers 5 days and 1 day before ozone did not change, but responsiveness and epithelial neutrophils increased markedly after ozone. In treated dogs, circulating neutrophils decreased from 8.9 +/- 2.2 to 0.6 +/- 0.01 X 10(3) per mm3 (mean +/- SEM), and responsiveness before ozone did not change. Furthermore, increases in responsiveness and epithelial neutrophils did not occur after ozone. Six wk after stopping hydroxyurea, responsiveness and epithelial neutrophils increased markedly after ozone. The results suggest that ozone-induced hyperresponsiveness may depend on the mobilization of neutrophils into the airways.

  15. Dopamine-sensitive signaling mediators modulate psychostimulant-induced ultrasonic vocalization behavior in rats.

    PubMed

    Williams, Stacey N; Undieh, Ashiwel S

    2016-01-01

    The mesolimbic dopamine system plays a major role in psychostimulant-induced ultrasonic vocalization (USV) behavior in rodents. Within this system, psychostimulants elevate synaptic concentrations of dopamine thereby leading to exaggerated activation of postsynaptic dopamine receptors within the D1-like and D2-like subfamilies. Dopamine receptor stimulation activate several transmembrane signaling systems and cognate intracellular mediators; downstream activation of transcription factors then conveys the information from receptor activation to appropriate modulation of cellular and physiologic functions. We previously showed that cocaine-induced USV behavior was associated with enhanced expression of the neurotrophin BDNF. Like cocaine, amphetamine also increases synaptic dopamine levels, albeit primarily through facilitating dopamine release. Therefore, in the present study we investigated whether amphetamine and cocaine similarly activate dopamine-linked signaling cascades to regulate intracellular mediators leading to induction of USV behavior. The results show that amphetamine increased the emission of 50kHz USVs and this effect was blocked by SCH23390, a D1 receptor antagonist. Similar to cocaine, amphetamine increased BDNF protein expression in discrete brain regions, while pretreatment with K252a, a trkB neurotrophin receptor inhibitor, significantly reduced amphetamine-induced USV behavior. Inhibition of cyclic-AMP/PKA signaling with H89 or inhibition of PLC signaling with U73122 significantly blocked both the acute and subchronic amphetamine-induced USV behavior. In contrast, pharmacologic inhibition of either pathway enhanced cocaine-induced USV behavior. Although cocaine and amphetamine similarly modulate neurotrophin expression and USV, the molecular mechanisms by which these psychostimulants differentially activate dopamine receptor subtypes or other monoaminergic systems may be responsible for the distinct aspects of behavioral responses. PMID:26275925

  16. The role of endogenous serotonin in methamphetamine-induced neurotoxicity to dopamine nerve endings of the striatum.

    PubMed

    Thomas, David M; Angoa Prez, Mariana; Francescutti-Verbeem, Dina M; Shah, Mrudang M; Kuhn, Donald M

    2010-11-01

    Methamphetamine (METH) is a neurotoxic drug of abuse that damages the dopamine (DA) neuronal system in a highly delimited manner. The brain structure most affected by METH is the striatum where long-term DA depletion and microglial activation are maximal. Endogenous DA has been implicated as a critical participant in METH-induced neurotoxicity, most likely as a substrate for non-enzymatic oxidation by METH-generated reactive oxygen species. The striatum is also extensively innervated by serotonin (5HT) nerve endings and this neurochemical system is modified by METH in much the same manner as seen in DA nerve endings (i.e., increased release of 5HT, loss of function in tryptophan hydroxylase and the serotonin transporter, long-term depletion of 5HT stores). 5HT can also be modified by reactive oxygen species to form highly reactive species that damage neurons but its role in METH neurotoxicity has not been assessed. Increases in 5HT levels with 5-hydroxytryptophan do not change METH-induced neurotoxicity to the DA nerve endings as revealed by reductions in DA, tyrosine hydroxylase and dopamine transporter levels. Partial reductions in 5HT with p-chlorophenylalanine are without effect on METH toxicity, despite the fact that p-chlorophenylalanine largely prevents METH-induced hyperthermia. Mice lacking the gene for brain tryptophan hydroxylase 2 are devoid of brain 5HT and respond to METH in the same manner as wild-type controls, despite showing enhanced drug-induced hyperthermia. Taken together, the present results indicate that endogenous 5HT does not appear to play a role in METH-induced damage to DA nerve endings of the striatum. PMID:20722968

  17. The Roles of Dopamine Transport Inhibition and Dopamine Release Facilitation in Wake Enhancement and Rebound Hypersomnolence Induced by Dopaminergic Agents

    PubMed Central

    Gruner, John A.; Marcy, Val R.; Lin, Yin-Guo; Bozyczko-Coyne, Donna; Marino, Michael J.; Gasior, Maciej

    2009-01-01

    Study Objective: Rebound hypersomnolence (RHS: increased sleep following increased wake) is a limiting side-effect of many wake-promoting agents. In particular, RHS in the first few hours following wake appears to be associated with dopamine (DA)-releasing agents, e.g., amphetamine, but whether it can also be produced by DA transporter (DAT) inhibition alone is unknown. In these studies, DA-releasing and DAT-inhibiting agents and their interaction were systematically examined for their ability to increase wake and induce RHS. Design: Chronically implanted rats were evaluated in a blinded, pseudo-randomized design. Participants: 237 rats were used in these studies with 1 week between repeat tests. Interventions: Animals were habituated overnight and dosed the next day, 5 h after lights on, with test agents. Measurements and Results: Sleep/wake activity and RHS were evaluated using EEG/EMG recording up to 22 h post dosing. In vitro dopamine release was evaluated in rat synaptosomes. At doses that produced equal increases in wake, DA-releasing (amphetamine, methamphetamine, phentermine) and several DAT-inhibiting agents (cocaine, bupropion, and methylphenidate) produced RHS during the first few hours after the onset of sleep recovery. However, other DAT-inhibiting agents (mazindol, nomifensine, GBR-12909, and GBR-12935) did not produce RHS. Combination treatment with amphetamine and nomifensine produced waking activity greater than the sum of their individual activities alone while ameliorating the amphetamine-like RHS. In rat synaptosomes, nomifensine reduced the potency of amphetamine to induce DA release ?270-fold, potentially explaining its action in ameliorating amphetamine-induced RHS. Conclusions: All DA releasing agents tested, and some DAT-inhibiting agents, produced RHS at equal wake-promoting doses. Thus amphetamine-like DA release appears sufficient for inducing RHS, but additional properties (pharmacologic and/or pharmacokinetic) evidently underlie RHS of other DAT inhibitors. Enhancing wake while mitigating RHS can be achieved by combining DAT-inhibiting and DA-releasing agents. Citation: Gruner JA; Marcy VR; LinYG; Bozyczko-Coyne D; Marino MJ; Gasior M. The roles of dopamine transport inhibition and dopamine release facilitation in wake enhancement and rebound hypersomnolence induced by dopaminergic agents. SLEEP 2009;32(11):1425-1438. PMID:19928382

  18. Dieldrin exposure induces oxidative damage in the mouse nigrostriatal dopamine system

    PubMed Central

    Hatcher, Jaime M.; Richardson, Jason R.; Guillot, Thomas S.; McCormack, Alison L.; Di Monte, Donato A.; Jones, Dean P.; Pennell, Kurt D.; Miller, Gary W.

    2007-01-01

    Numerous epidemiological studies have shown an association between pesticide exposure and an increased risk of developing Parkinsons disease (PD). Here, we provide evidence that the insecticide dieldrin causes specific oxidative damage in the nigrostriatal dopamine (DA) system. We report that exposure of mice to low levels of dieldrin for 30 days resulted in alterations in dopamine-handling as evidenced by a decrease in dopamine metabolites, DOPAC (31.7% decrease) and HVA (29.2% decrease) and significantly increased cysteinyl-catechol levels in the striatum. Furthermore, dieldrin resulted in a 53% decrease in total glutathione, an increase in the redox potential of glutathione, and a 90% increase in protein carbonyls. ?-Synuclein protein expression was also significantly increased in the striatum (25% increase). Finally, dieldrin caused a significant decrease in striatal expression of the dopamine transporter as measured by 3H-WIN 35,428 binding and 3H-dopamine uptake. These alterations occurred in the absence of dopamine neuron loss in the substantia nigra pars compacta. These effects represent the ability of low doses of dieldrin to increase the vulnerability of nigrostriatal dopamine neurons by inducing oxidative stress and suggest that pesticide exposure may act as a promoter of PD. PMID:17291500

  19. Dopamine-related deficit in reward learning after catecholamine depletion in unmedicated, remitted subjects with bulimia nervosa.

    PubMed

    Grob, Simona; Pizzagalli, Diego A; Dutra, Sunny J; Stern, Jair; Mrgeli, Hanspeter; Milos, Gabriella; Schnyder, Ulrich; Hasler, Gregor

    2012-07-01

    Disturbances in reward processing have been implicated in bulimia nervosa (BN). Abnormalities in processing reward-related stimuli might be linked to dysfunctions of the catecholaminergic neurotransmitter system, but findings have been inconclusive. A powerful way to investigate the relationship between catecholaminergic function and behavior is to examine behavioral changes in response to experimental catecholamine depletion (CD). The purpose of this study was to uncover putative catecholaminergic dysfunction in remitted subjects with BN who performed a reinforcement-learning task after CD. CD was achieved by oral alpha-methyl-para-tyrosine (AMPT) in 19 unmedicated female subjects with remitted BN (rBN) and 28 demographically matched healthy female controls (HC). Sham depletion administered identical capsules containing diphenhydramine. The study design consisted of a randomized, double-blind, placebo-controlled crossover, single-site experimental trial. The main outcome measures were reward learning in a probabilistic reward task analyzed using signal-detection theory. Secondary outcome measures included self-report assessments, including the Eating Disorder Examination-Questionnaire. Relative to healthy controls, rBN subjects were characterized by blunted reward learning in the AMPT--but not in placebo--condition. Highlighting the specificity of these findings, groups did not differ in their ability to perceptually distinguish between stimuli. Increased CD-induced anhedonic (but not eating disorder) symptoms were associated with a reduced response bias toward a more frequently rewarded stimulus. In conclusion, under CD, rBN subjects showed reduced reward learning compared with healthy control subjects. These deficits uncover disturbance of the central reward processing systems in rBN related to altered brain catecholamine levels, which might reflect a trait-like deficit increasing vulnerability to BN. PMID:22491353

  20. Pyrethroid pesticide-induced alterations in dopamine transporter function

    PubMed Central

    Elwan, Mohamed A.; Richardson, Jason R.; Guillot, Thomas S.; Caudle, W. Michael; Miller, Gary W.

    2016-01-01

    Parkinsons disease (PD) is a progressive neurodegenerative disease affecting the nigrostriatal dopaminergic pathway. Several epidemiological studies have demonstrated an association between pesticide exposure and the incidence of PD. Studies from our laboratory and others have demonstrated that certain pesticides increase levels of the dopamine transporter (DAT), an integral component of dopaminergic neurotransmission and a gateway for dopaminergic neurotoxins. Here, we report that repeated exposure (3 injections over 2 weeks) of mice to two commonly used pyrethroid pesticides, deltamethrin (3 mg/kg) and permethrin (0.8 mg/kg), increases DAT-mediated dopamine uptake by 31 and 28%, respectively. Using cells stably expressing DAT, we determined that exposure (10 min) to deltamethrin and permethrin (1 nM100 ?M) had no effect on DAT-mediated dopamine uptake. Extending exposures to both pesticides for 30 min (10 ?M) or 24 h (1, 5, and 10 ?M) resulted in significant decrease in dopamine uptake. This reduction was not the result of competitive inhibition, loss of DAT protein, or cytotoxicity. However, there was an increase in DNA fragmentation, an index of apoptosis, in cells exhibiting reduced uptake at 30 min and 24 h. These data suggest that up-regulation of DAT by in vivo pyrethroid exposure is an indirect effect and that longer-term exposure of cells results in apoptosis. Since DAT can greatly affect the vulnerability of dopamine neurons to neurotoxicants, up-regulation of DAT by deltamethrin and permethrin may increase the susceptibility of dopamine neurons to toxic insult, which may provide insight into the association between pesticide exposure and PD. PMID:16005927

  1. Pyrethroid pesticide-induced alterations in dopamine transporter function

    SciTech Connect

    Elwan, Mohamed A.; Richardson, Jason R.; Guillot, Thomas S.; Caudle, W. Michael; Miller, Gary W. . E-mail: gary.miller@emory.edu

    2006-03-15

    Parkinson's disease (PD) is a progressive neurodegenerative disease affecting the nigrostriatal dopaminergic pathway. Several epidemiological studies have demonstrated an association between pesticide exposure and the incidence of PD. Studies from our laboratory and others have demonstrated that certain pesticides increase levels of the dopamine transporter (DAT), an integral component of dopaminergic neurotransmission and a gateway for dopaminergic neurotoxins. Here, we report that repeated exposure (3 injections over 2 weeks) of mice to two commonly used pyrethroid pesticides, deltamethrin (3 mg/kg) and permethrin (0.8 mg/kg), increases DAT-mediated dopamine uptake by 31 and 28%, respectively. Using cells stably expressing DAT, we determined that exposure (10 min) to deltamethrin and permethrin (1 nM-100 {mu}M) had no effect on DAT-mediated dopamine uptake. Extending exposures to both pesticides for 30 min (10 {mu}M) or 24 h (1, 5, and 10 {mu}M) resulted in significant decrease in dopamine uptake. This reduction was not the result of competitive inhibition, loss of DAT protein, or cytotoxicity. However, there was an increase in DNA fragmentation, an index of apoptosis, in cells exhibiting reduced uptake at 30 min and 24 h. These data suggest that up-regulation of DAT by in vivo pyrethroid exposure is an indirect effect and that longer-term exposure of cells results in apoptosis. Since DAT can greatly affect the vulnerability of dopamine neurons to neurotoxicants, up-regulation of DAT by deltamethrin and permethrin may increase the susceptibility of dopamine neurons to toxic insult, which may provide insight into the association between pesticide exposure and PD.

  2. Evidence for a Role of Transporter-Mediated Currents in the Depletion of Brain Serotonin Induced by Serotonin Transporter Substrates

    PubMed Central

    Baumann, Michael H; Bulling, Simon; Benaderet, Tova S; Saha, Kusumika; Ayestas, Mario A; Partilla, John S; Ali, Syed F; Stockner, Thomas; Rothman, Richard B; Sandtner, Walter; Sitte, Harald H

    2014-01-01

    Serotonin (5-HT) transporter (SERT) substrates like fenfluramine and 3,4-methylenedioxymethamphetamine cause long-term depletion of brain 5-HT, while certain other substrates do not. The 5-HT deficits produced by SERT substrates are dependent upon transporter proteins, but the exact mechanisms responsible are unclear. Here, we compared the pharmacology of several SERT substrates: fenfluramine, d-fenfluramine, 1-(m-chlorophenyl)piperazine (mCPP) and 1-(m-trifluoromethylphenyl)piperainze (TFMPP), to establish relationships between acute drug mechanisms and the propensity for long-term 5-HT depletions. In vivo microdialysis was carried out in rat nucleus accumbens to examine acute 5-HT release and long-term depletion in the same subjects. In vitro assays were performed to measure efflux of [3H]5-HT in rat brain synaptosomes and transporter-mediated ionic currents in SERT-expressing Xenopus oocytes. When administered repeatedly to rats (6 mg/kg, i.p., four doses), all drugs produce large sustained elevations in extracellular 5-HT (>5-fold) with minimal effects on dopamine. Importantly, 2 weeks after dosing, only rats exposed to fenfluramine and d-fenfluramine display depletion of brain 5-HT. All test drugs evoke fluoxetine-sensitive efflux of [3H]5-HT from synaptosomes, but d-fenfluramine and its bioactive metabolite d-norfenfluramine induce significantly greater SERT-mediated currents than phenylpiperazines. Our data confirm that drug-induced 5-HT release probably does not mediate 5-HT depletion. However, the magnitude of transporter-mediated inward current may be a critical factor in the cascade of events leading to 5-HT deficits. This hypothesis warrants further study, especially given the growing popularity of designer drugs that target SERT. PMID:24287719

  3. Evidence for a role of transporter-mediated currents in the depletion of brain serotonin induced by serotonin transporter substrates.

    PubMed

    Baumann, Michael H; Bulling, Simon; Benaderet, Tova S; Saha, Kusumika; Ayestas, Mario A; Partilla, John S; Ali, Syed F; Stockner, Thomas; Rothman, Richard B; Sandtner, Walter; Sitte, Harald H

    2014-05-01

    Serotonin (5-HT) transporter (SERT) substrates like fenfluramine and 3,4-methylenedioxymethamphetamine cause long-term depletion of brain 5-HT, while certain other substrates do not. The 5-HT deficits produced by SERT substrates are dependent upon transporter proteins, but the exact mechanisms responsible are unclear. Here, we compared the pharmacology of several SERT substrates: fenfluramine, d-fenfluramine, 1-(m-chlorophenyl)piperazine (mCPP) and 1-(m-trifluoromethylphenyl)piperainze (TFMPP), to establish relationships between acute drug mechanisms and the propensity for long-term 5-HT depletions. In vivo microdialysis was carried out in rat nucleus accumbens to examine acute 5-HT release and long-term depletion in the same subjects. In vitro assays were performed to measure efflux of [(3)H]5-HT in rat brain synaptosomes and transporter-mediated ionic currents in SERT-expressing Xenopus oocytes. When administered repeatedly to rats (6 mg/kg, i.p., four doses), all drugs produce large sustained elevations in extracellular 5-HT (>5-fold) with minimal effects on dopamine. Importantly, 2 weeks after dosing, only rats exposed to fenfluramine and d-fenfluramine display depletion of brain 5-HT. All test drugs evoke fluoxetine-sensitive efflux of [(3)H]5-HT from synaptosomes, but d-fenfluramine and its bioactive metabolite d-norfenfluramine induce significantly greater SERT-mediated currents than phenylpiperazines. Our data confirm that drug-induced 5-HT release probably does not mediate 5-HT depletion. However, the magnitude of transporter-mediated inward current may be a critical factor in the cascade of events leading to 5-HT deficits. This hypothesis warrants further study, especially given the growing popularity of designer drugs that target SERT. PMID:24287719

  4. Depletion-induced shape and size selection of gold nanoparticles.

    PubMed

    Park, Kyoungweon; Koerner, Hilmar; Vaia, Richard A

    2010-04-14

    For nanoparticle-based technologies, efficient and rapid approaches that yield particles of high purity with a specific shape and size are critical to optimize the nanostructure-dependent optical, electrical, and magnetic properties, and not bias conclusions due to the existence of impurities. Notwithstanding the continual improvement of chemical methods for shaped nanoparticle synthesis, byproducts are inevitable. Separation of these impurities may be achieved, albeit inefficiently, through repeated centrifugation steps only when the sedimentation coefficient of the species shows sufficient contrast. We demonstrate a robust and efficient procedure of shape and size selection of Au nanoparticles (NPs) through the formation of reversible flocculates by surfactant micelle induced depletion interaction. Au NP flocculates form at a critical surfactant micelle molar concentration, C(m)* where the number of surfactant micelles is sufficient to induce an attractive potential energy between the Au NPs. Since the magnitude of this potential depends on the interparticle contact area of Au NPs, separation is achieved even for the NPs of the same mass with different shape by tuning the surfactant concentration and extracting flocculates from the sediment by centrifugation or gravitational sedimentation. The refined NPs are redispersed by subsequently decreasing the surfactant concentration to reduce the effective attractive potential. These concepts provide a robust method to improve the quality of large scale synthetic approaches of a diverse array of NPs, as well as fine-tune interparticle interactions for directed assembly, both crucial challenges to the continual realization of the broad technological potential of monodispersed NPs. PMID:20349972

  5. Effects of adolescent social defeat on adult amphetamine-induced locomotion and corticoaccumbal dopamine release in male rats

    PubMed Central

    Burke, Andrew R.; Forster, Gina L.; Novick, Andrew M.; Roberts, Christina L.; Watt, Michael J.

    2012-01-01

    Maturation of mesocorticolimbic dopamine systems occurs during adolescence, and exposure to social stress during this period results in behavioral dysfunction including substance abuse disorders. Adult male rats exposed to repeated social defeat in adolescence exhibit reduced basal dopamine tissue content in the medial prefrontal cortex, altered dopamine tissue content in corticoaccumbal dopamine regions following acute amphetamine, and increased amphetamine conditioned place preference following repeated amphetamine treatment. Such changes may reflect altered amphetamine-induced extracellular dopamine release in the corticoaccumbal regions. Therefore, we used in vivo microdialysis to measure extracellular dopamine simultaneously within the medial prefrontal cortex and nucleus accumbens core of previously defeated rats and controls, in response to either acute or repeated (7 daily injections) of amphetamine (1.0 mg/kg). Locomotion responses to acute / repeated amphetamine were also assessed the day prior to taking dopamine measurements. Adolescent defeat potentiated adult locomotion responses to acute amphetamine, which was negatively correlated with attenuated amphetamine-induced dopamine release in the medial prefrontal cortex, but there was no difference in amphetamine-induced accumbal dopamine release. However, both locomotion and corticoaccumbal dopamine responses to repeated amphetamine were equivalent between previously defeated rats and controls. These data suggest adolescent defeat enhances behavioral responses to initial amphetamine exposure as a function of diminished prefrontal cortex dopamine activity, which may be sufficient to promote subsequently enhanced seeking of drug-associated cues. Interestingly, repeated amphetamine treatment appears to normalize amphetamine-elicited locomotion and cortical dopamine responses observed in adult rats exposed to adolescent social defeat, providing implications for treating stress-induced dopamine dysfunction. PMID:23220295

  6. Compartmental analysis of tyramine-induced norepinephrine depletion.

    PubMed

    Rapoport, R M; Takimoto, G S; Cho, A K

    1981-01-01

    Tyramine-dependent depletion of norepinephrine was shown to occur from a single kinetically defined compartment. The kinetics of depletion were related to the tyramine concentration and were independent of the amount of norepinephrine within the neuron. Tyramine depleted equivalent amounts of norepinephrine from cytoplasmic, biosynthetic, stable and labile intraneuronal storage compartments by a cocaine-sensitive process. The norepinephrine specific activity of the thoracic aorta remained constant even after greater than 80% depletion due to tyramine. The results show no evidence for a tyramine-resistant pool(s) of norepinephrine within adrenergic neurons. PMID:7267695

  7. Pathological gambling induced by dopamine antagonists: a case report.

    PubMed

    Grtsch, Philipp; Lange, Claudia; Wiesbeck, Gerhard A; Lang, Undine

    2015-03-01

    Pathological gambling is defined as inappropriate, persistent, and maladaptive gambling behaviour. It is a non-pharmacological addiction classified as an impulse control disorder. However, pathological gambling has been associated with dopamine agonist use. Here we report of a 28-year-old man with a first major depressive episode and a post-traumatic stress disorder who has been treated with a combination of the serotonine/noradrenaline reuptake inhibitor duloxetine and the tricyclic antidepressant maprotiline. The administration of antipsychotic flupentixole (up to 7 mg) turned this slight online poker gambler into an excessive gambler. Only after the discontinuation of the antidopaminergic agents and the switch to bupropion did this gambling behaviour stop which suggests a causal relationship between dopamine antagonists and pathological gambling. PMID:24356928

  8. Dopamine inhibits lipopolysaccharide-induced nitric oxide production through the formation of dopamine quinone in murine microglia BV-2 cells.

    PubMed

    Yoshioka, Yasuhiro; Sugino, Yuta; Tozawa, Azusa; Yamamuro, Akiko; Kasai, Atsushi; Ishimaru, Yuki; Maeda, Sadaaki

    2016-02-01

    Dopamine (DA) has been suggested to modulate functions of glial cells including microglial cells. To reveal the regulatory role of DA in microglial function, in the present study, we investigated the effect of DA on lipopolysaccharide (LPS)-induced nitric oxide (NO) production in murine microglial cell line BV-2. Pretreatment with DA for 24 h concentration-dependently attenuated LPS-induced NO production in BV-2 cells. The inhibitory effect of DA on LPS-induced NO production was not inhibited by SCH-23390 and sulpiride, D1-like and D2-like DA receptor antagonists, respectively. In addition, pretreatment with (-)-(6aR,12bR)-4,6,6a,7,8,12b-Hexahydro-7-methylindolo[4,3-a]phenanthridin (CY 208-243) and bromocriptine, D1-like and D2-like DA receptor agonists, respectively, did not affect the LPS-induced NO production. N-Acetylcysteine, which inhibits DA oxidation, completely inhibited the effect of DA. Tyrosinase, which catalyzes the oxidation of DA to DA quionone (DAQ), accelerated the inhibitory effect of DA on LPS-induced NO production. These results suggest that DA attenuates LPS-induced NO production through the formation of DAQ in BV-2 cells. PMID:26908040

  9. Depleted uranium induces neoplastic transformation in human lung epithelial cells.

    PubMed

    Xie, Hong; LaCerte, Carolyne; Thompson, W Douglas; Wise, John Pierce

    2010-02-15

    Depleted uranium (DU) is commonly used in military armor and munitions, and thus, exposure of soldiers and noncombatants is frequent and widespread. Previous studies have shown that DU has both chemical and radiological toxicity and that the primary route of exposure of DU to humans is through inhalation and ingestion. However, there is limited research information on the potential carcinogenicity of DU in human bronchial cells. Accordingly, we determined the neoplastic transforming ability of particulate DU to human bronchial epithelial cells (BEP2D). We observed the loss of contact inhibition and anchorage independent growth in cells exposed to DU after 24 h. We also characterized these DU-induced transformed cell lines and found that 40% of the cell lines exhibit alterations in plating efficiency and no significant changes in the cytotoxic response to DU. Cytogenetic analyses showed that 53% of the DU-transformed cell lines possess a hypodiploid phenotype. These data indicate that human bronchial cells are transformed by DU and exhibit significant chromosome instability consistent with a neoplastic phenotype. PMID:20000475

  10. Dopamine-Induced Nonmotor Symptoms of Parkinson's Disease

    PubMed Central

    Park, Ariane; Stacy, Mark

    2011-01-01

    Nonmotor symptoms of Parkinson's disease (PD) may emerge secondary to the underlying pathogenesis of the disease, while others are recognized side effects of treatment. Inevitably, there is an overlap as the disease advances and patients require higher dosages and more complex medical regimens. The non-motor symptoms that emerge secondary to dopaminergic therapy encompass several domains, including neuropsychiatric, autonomic, and sleep. These are detailed in the paper. Neuropsychiatric complications include hallucinations and psychosis. In addition, compulsive behaviors, such as pathological gambling, hypersexuality, shopping, binge eating, and punding, have been shown to have a clear association with dopaminergic medications. Dopamine dysregulation syndrome (DDS) is a compulsive behavior that is typically viewed through the lens of addiction, with patients needing escalating dosages of dopamine replacement therapy. Treatment side effects on the autonomic system include nausea, orthostatic hypotension, and constipation. Sleep disturbances include fragmented sleep, nighttime sleep problems, daytime sleepiness, and sleep attacks. Recognizing the non-motor symptoms that can arise specifically from dopamine therapy is useful to help optimize treatment regimens for this complex disease. PMID:21603184

  11. Caffeine expectancies but not caffeine reduce depletion-induced aggression.

    PubMed

    Denson, Thomas F; Jacobson, Mandi; von Hippel, William; Kemp, Richard I; Mak, Tinnie

    2012-03-01

    Caffeine is the most widely consumed central nervous system stimulant in the world, yet little is known about its effects on aggressive behavior. Individuals often consume caffeine to increase energy and ward off mental depletion. Because mental depletion increases aggression when people are provoked, caffeine might reduce aggression by ameliorating the negative effects of depletion. In 2 experiments, participants consumed a 200-mg caffeine tablet or a placebo, were mentally depleted or not, and then provoked and given the opportunity to retaliate with a blast of white noise. Results showed that consuming a placebo reduced aggression relative to both caffeine (Experiments 1 and 2) and a no-pill control condition (Experiment 2). These data suggest that expectancies about the effects of caffeine in the absence of the pharmacological effects of the drug can reduce aggression when mentally depleted. PMID:21766974

  12. Metallothionein deficiency aggravates depleted uranium-induced nephrotoxicity.

    PubMed

    Hao, Yuhui; Huang, Jiawei; Gu, Ying; Liu, Cong; Li, Hong; Liu, Jing; Ren, Jiong; Yang, Zhangyou; Peng, Shuangqing; Wang, Weidong; Li, Rong

    2015-09-15

    Depleted uranium (DU) has been widely used in both civilian and military activities, and the kidney is the main target organ of DU during acute high-dose exposures. In this study, the nephrotoxicity caused by DU in metallothionein-1/2-null mice (MT-/-) and corresponding wild-type (MT+/+) mice was investigated to determine any associations with MT. Each MT-/- or MT+/+ mouse was pretreated with a single dose of DU (10mg/kg, intraperitoneal injection) or an equivalent volume of saline. After 4days of DU administration, kidney changes were assessed. After DU exposure, serum creatinine and serum urea nitrogen in MT-/- mice significantly increased than in MT+/+ mice, with more severe kidney pathological damage. Moreover, catalase and superoxide dismutase (SOD) decreased, and generation of reactive oxygen species and malondialdehyde increased in MT-/- mice. The apoptosis rate in MT-/- mice significantly increased, with a significant increase in both Bax and caspase 3 and a decrease in Bcl-2. Furthermore, sodium-glucose cotransporter (SGLT) and sodium-phosphate cotransporter (NaPi-II) were significantly reduced after DU exposure, and the change of SGLT was more evident in MT-/- mice. Finally, exogenous MT was used to evaluate the correlation between kidney changes induced by DU and MT doses in MT-/- mice. The results showed that, the pathological damage and cell apoptosis decreased, and SOD and SGLT levels increased with increasing dose of MT. In conclusion, MT deficiency aggravated DU-induced nephrotoxicity, and the molecular mechanisms appeared to be related to the increased oxidative stress and apoptosis, and decreased SGLT expression. PMID:26148447

  13. Dopamine induces growth inhibition and vascular normalization through reprogramming M2-polarized macrophages in rat C6 glioma.

    PubMed

    Qin, Tian; Wang, Chenlong; Chen, Xuewei; Duan, Chenfan; Zhang, Xiaoyan; Zhang, Jing; Chai, Hongyan; Tang, Tian; Chen, Honglei; Yue, Jiang; Li, Ying; Yang, Jing

    2015-07-15

    Dopamine (DA), a monoamine catecholamine neurotransmitter with antiangiogenic activity, stabilizes tumor vessels in colon, prostate and ovarian cancers, thus increases chemotherapeutic efficacy. Here, in the rat C6 glioma models, we investigated the vascular normalization effects of DA and its mechanisms of action. DA (25, 50mg/kg) inhibited tumor growth, while a precursor of DA (levodopa) prolonged the survival time of rats bearing orthotopic C6 glioma. DA improved tumor perfusion, with significant effects from day 3, and a higher level at days 5 to 7. In addition, DA decreased microvessel density and hypoxia-inducible factor-1? expression in tumor tissues, while increasing the coverage of pericyte. Conversely, an antagonist of dopamine receptor 2 (DR2) (eticlopride) but not DR1 (butaclamol) abrogated DA-induced tumor regression and vascular normalization. Furthermore, DA improved the delivery and efficacy of temozolomide therapy. Importantly, DA increased representative M1 markers (iNOS, CXCL9, etc.), while decreasing M2 markers (CD206, arginase-1, etc.). Depletion of macrophages by clodronate or zoledronic acid attenuated the effects of DA. Notably, DA treatment induced M2-to-M1 polarization in RAW264.7 cells and mouse peritoneal macrophages, and enhanced the migration of pericyte-like cells (10T1/2), which was reversed by eticlopride or DR2-siRNA. Such changes were accompanied by the downregulation of VEGF/VEGFR2 signaling. In summary, DA induces growth inhibition and vascular normalization through reprogramming M2-polarized macrophages. Thus, targeting the tumor microvasculature by DA represents a promising strategy for human glioma therapy. PMID:25818600

  14. Modulation by D1 and D2 dopamine receptors of ATP-induced release of intracellular Ca2+ in cultured rat striatal neurons.

    PubMed

    Rubini, Patrizia; Engelhardt, Johannes; Wirkner, Kerstin; Illes, Peter

    2008-01-01

    The aim of the present study was to investigate, whether dopamine D1 and/or D2 receptors are able to interfere with the ATP-induced increase of the intracellular Ca2+ concentration ([Ca2+]i) in cultured striatal neurons identified by their morphological characteristics and their [Ca2+]i transients in response to a high-K+ superfusion medium. ATP appeared to release Ca2+ mostly from an intracellular pool, since its effect was markedly depressed in the presence of cyclopiazonic acid, which is known to deplete such storage sites [Rubini, P., Pinkwart, C., Franke, H., Gerevich, Z., Nörenberg, W., Illes, P., 2006. Regulation of intracellular Ca2+ by P2Y1 receptors may depend on the developmental stage of cultured rat striatal neurons. J. Cell. Physiol. 209, 81-93]. The mixed D1/D2 receptor agonist dopamine increased the ATP-induced [Ca2+]i transients in a subpopulation of neurons. At the same time, dopamine did not alter the responses to K+ in these cells. The selective D1 (SKF 83566) and D2 (sulpiride) receptor antagonists failed to modify the effect of ATP, but unmasked in the previously unresponsive neurons an inhibitory and facilitatory effect of dopamine, respectively. A combination of the two antagonists resulted in a failure of dopamine to modulate the [Ca2+]i responses in any cell investigated. In conclusion, D1 and D2 receptors may modulate in an opposite manner the signalling pathways of P2Y1 receptors in striatal neurons and thereby alter their development/growth or their cellular excitability and/or the release of GABA from their terminals. PMID:17664020

  15. Methamphetamine-Induced Dopamine-Independent Alterations in Striatal Gene Expression in the 6-Hydroxydopamine Hemiparkinsonian Rats

    PubMed Central

    Cadet, Jean Lud; Brannock, Christie; Krasnova, Irina N.; Ladenheim, Bruce; McCoy, Michael T.; Chou, Jenny; Lehrmann, Elin; Wood, William H.; Becker, Kevin G.; Wang, Yun

    2010-01-01

    Unilateral injections of 6-hydroxydopamine into the medial forebrain bundle are used extensively as a model of Parkinson's disease. The present experiments sought to identify genes that were affected in the dopamine (DA)denervated striatum after 6-hydroxydopamine-induced destruction of the nigrostriatal dopaminergic pathway in the rat. We also examined whether a single injection of methamphetamine (METH) (2.5 mg/kg) known to cause changes in gene expression in the normally DA-innervated striatum could still influence striatal gene expression in the absence of DA. Unilateral injections of 6-hydroxydopamine into the medial forebrain bundle resulted in METH-induced rotational behaviors ipsilateral to the lesioned side and total striatal DA depletion on the lesioned side. This injection also caused decrease in striatal serotonin (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) levels. DA depletion was associated with increases in 5-HIAA/5-HT ratios that were potentiated by the METH injection. Microarray analyses revealed changes ( 1.7-fold, p<0.025) in the expression of 67 genes on the lesioned side in comparison to the intact side of the saline-treated hemiparkinsonian animals. These include follistatin, neuromedin U, and tachykinin 2 which were up-regulated. METH administration caused increases in the expression of c-fos, Egr1, and Nor-1 on the intact side. On the DA-depleted side, METH administration also increased the expression of 61 genes including Pdgf-d and Cox-2. There were METH-induced changes in 16 genes that were common in the DA-innervated and DA-depleted sides. These include c-fos and Nor-1 which show greater changes on the normal DA side. Thus, the present study documents, for the first time, that METH mediated DA-independent changes in the levels of transcripts of several genes in the DA-denervated striatum. Our results also implicate 5-HT as a potential player in these METH-induced alterations in gene expression because the METH injection also caused significant increases in 5-HIAA/5-HT ratios on the DA-depleted side. PMID:21179447

  16. Adaptations of Presynaptic Dopamine Terminals Induced by Psychostimulant Self-Administration

    PubMed Central

    2015-01-01

    A great deal of research has focused on investigating neurobiological alterations induced by chronic psychostimulant use in an effort to describe, understand, and treat the pathology of psychostimulant addiction. It has been known for several decades that dopamine neurotransmission in the nucleus accumbens is integrally involved in the selection and execution of motivated and goal-directed behaviors, and that psychostimulants act on this system to exert many of their effects. As such, a large body of work has focused on defining the consequences of psychostimulant use on dopamine signaling in the striatum as it relates to addictive behaviors. Here, we review presynaptic dopamine terminal alterations observed following self-administration of cocaine and amphetamine, as well as possible mechanisms by which these alterations occur and their impact on the progression of addiction. PMID:25491345

  17. Dopamine and paraquat enhance ?-synuclein-induced alterations in membrane conductance

    PubMed Central

    Feng, Li Rebekah; Maguire-Zeiss, Kathleen A.

    2011-01-01

    We have previously demonstrated that ?-synuclein overexpression increases the membrane conductance of dopaminergic-like cells. Although ?-synuclein is thought to play a central role in the pathogenesis of several neurodegenerative diseases including Parkinsons disease, multiple system atrophy and diffuse Lewy body disease the mechanism of action is not completely understood. In this study we sought to determine whether multiple factors act together with ?-synuclein to engender cell vulnerability through an augmentation of membrane conductance. Here we employed a cell model that mimics dopaminergic neurons coupled with ?-synuclein overexpression and oxidative stressors. We demonstrate an enhancement of ?-synuclein-induced toxicity in the presence of combined treatment with dopamine and paraquat, two molecules known to incite oxidative stress. In addition we show that combined dopamine and paraquat treatment increases the expression of heme oxygenase-1, an antioxidant response protein. Finally, we demonstrate for the first time that combined treatment of dopaminergic cells with paraquat and dopamine enhances ?-synuclein-induced leak channel properties resulting in increased membrane conductance. Importantly, these increases are most robust when both paraquat and dopamine are present suggesting the need for multiple oxidative insults to augment ?-synuclein-induced disruption of membrane integrity. PMID:21735318

  18. Aversive behavior induced by optogenetic inactivation of ventral tegmental area dopamine neurons is mediated by dopamine D2 receptors in the nucleus accumbens

    PubMed Central

    Danjo, Teruko; Yoshimi, Kenji; Funabiki, Kazuo; Yawata, Satoshi; Nakanishi, Shigetada

    2014-01-01

    Dopamine (DA) transmission from the ventral tegmental area (VTA) is critical for controlling both rewarding and aversive behaviors. The transient silencing of DA neurons is one of the responses to aversive stimuli, but its consequences and neural mechanisms regarding aversive responses and learning have largely remained elusive. Here, we report that optogenetic inactivation of VTA DA neurons promptly down-regulated DA levels and induced up-regulation of the neural activity in the nucleus accumbens (NAc) as evaluated by Fos expression. This optogenetic suppression of DA neuron firing immediately evoked aversive responses to the previously preferred dark room and led to aversive learning toward the optogenetically conditioned place. Importantly, this place aversion was abolished by knockdown of dopamine D2 receptors but not by that of D1 receptors in the NAc. Silencing of DA neurons in the VTA was thus indispensable for inducing aversive responses and learning through dopamine D2 receptors in the NAc. PMID:24737889

  19. Signaling Mechanisms in the Nitric Oxide Donor- and Amphetamine-Induced Dopamine Release in Mesencephalic Primary Cultured Neurons.

    PubMed

    Salum, Cristiane; Schmidt, Fanny; Michel, Patrick P; Del-Bel, Elaine; Raisman-Vozari, Rita

    2016-01-01

    Previous research has shown that nitric oxide (NO) synthase inhibitors prevent rodents' sensorimotor gating impairments induced by dopamine releasing drugs, such as amphetamine (Amph) and methylphenidate. The mechanisms of this effect have not been entirely understood. In the present work, we investigated some possible mechanisms by which the NO donor, NOC-12 (3-ethyl-3-(ethylaminoethyl)-1-hydroxy-2-oxo-1-triazene), influence spontaneous and Amph-induced dopamine release, using rat mesencephalic primary cultured neurons preparations. Our results showed that NOC-12 increased dopamine release in a concentration-dependent manner and potentiated the Amph-induced one. Dopamine release induced by NOC-12 was disrupted by N-acetyl-L-cystein (NAC-a free radical scavenger) and MK-801, a NMDA (N-methyl-D-aspartate) non-competitive antagonist, and was concentration dependently affected by oxadiazolo[4,3]quinoxalin-1-one, an inhibitor of the soluble guanylate cyclase (sGC). In contrast, dopamine released by Amph was facilitated by NAC and by MK-801 and not affected by nifedipine (a L-type-Ca(+2) channel blocker), which enhanced NOC-12-induced dopamine release. The present work demonstrates that DA release induced by NOC-12 is partially dependent on sGC and on NMDA activation, and is modulated by L-type Ca(+2) channel and the antioxidant NAC. This mechanism differs from the Amph-induced one, which appears not to depend on L-type Ca(+2) channel and seems to be facilitated by NMDA channel blocking and by NAC. These results suggest that Amph and NOC-12 induce dopamine release through complementary pathways, which may explain the potentiation of Amph-induced dopamine release by NOC-12. These findings contribute to understand the involvement of NO in dopamine-related neuropsychiatric and neurodegenerative diseases. PMID:26391887

  20. Intratracheal dopamine attenuates pulmonary edema and improves survival after ventilator-induced lung injury in rats

    PubMed Central

    Chamorro-Marn, Virginia; Garca-Delgado, Manuel; Touma-Fernndez, Angel; Aguilar-Alonso, Eduardo; Fernndez-Mondejar, Enrique

    2008-01-01

    Intoduction Clearance of alveolar oedema depends on active transport of sodium across the alveolar-epithelial barrier. ?-Adrenergic agonists increase clearance of pulmonary oedema, but it has not been established whether ?-agonist stimulation achieves sufficient oedema clearance to improve survival in animals. The objective of this study was to determine whether the increased pulmonary oedema clearance produced by intratracheal dopamine improves the survival of rats after mechanical ventilation with high tidal volume (HVT). Methods This was a randomized, controlled, experimental study. One hundred and thirty-two Wistar-Kyoto rats, weighing 250 to 300 g, were anaesthetized and cannulated via endotracheal tube. Pulmonary oedema was induced by endotracheal instillation of saline solution and mechanical ventilation with HVT. Two types of experiment were carried out. The first was an analysis of pulmonary oedema conducted in six groups of 10 rats ventilated with low (8 ml/kg) or high (25 ml/kg) tidal volume for 30 or 60 minutes with or without intratracheally instilled dopamine. At the end of the experiment the animals were exsanguinated and pulmonary oedema analysis performed. The second experiment was a survival analysis, which was conducted in two groups of 36 animals ventilated with HVT for 60 minutes with or without intratracheal dopamine; survival of the animals was monitored for up to 7 days after extubation. Results In animals ventilated at HVT with or without intratracheal dopamine, oxygen saturation deteriorated over time and was significantly higher at 30 minutes than at 60 minutes. After 60 minutes, a lower wet weight/dry weight ratio was observed in rats ventilated with HVT and instilled with dopamine than in rats ventilated with HVT without dopamine (3.9 0.27 versus 4.9 0.29; P = 0.014). Survival was significantly (P = 0.013) higher in animals receiving intratracheal dopamine and ventilated with HVT, especially at 15 minutes after extubation, when 11 of the 36 animals in the HVT group had died as compared with only one out of the 36 animals in the HVT plus dopamine group. Conclusion Intratracheal dopamine instillation increased pulmonary oedema clearance in rats ventilated with HVT, and this greater clearance was associated with improved survival. PMID:18331631

  1. Antipsychotic drugs rapidly induce dopamine neuron depolarization block in a developmental rat model of schizophrenia

    PubMed Central

    Valenti, Ornella; Cifelli, Pierangelo; Gill, Kathryn M.; Grace, Anthony A.

    2011-01-01

    Repeated administration of antipsychotic drugs to normal rats has been shown to induce a state of dopamine neuron inactivation known as depolarization block, which correlates with the ability of the drugs to exhibit antipsychotic efficacy and extrapyramidal side-effects in schizophrenia patients. Nonetheless, in normal rats depolarization block requires weeks of antipsychotic drug administration, whereas schizophrenia patients exhibit initial effects soon after initiating antipsychotic drug treatment. We now report that, in a developmental disruption rat model of schizophrenia (methyl-azoxymethanol acetate (20 mg/kg i.p.) injected into G17 pregnant female rats, with offspring tested as adults), the extant hyperdopaminergic state combines with the excitatory actions of a first (haloperidol; 0.6 mg/kg, i.p.)- and second (sertindole; 2.5 mg/kg, i.p.)-generation antipsychotic drug to rapidly induce depolarization block in ventral tegmental area dopamine neurons. Acute injection of either antipsychotic drug induced an immediate reduction in the number of spontaneously active dopamine neurons (cells per electrode track; termed population activity). Repeated administration of either antipsychotic drug for 1 day, 3 days, 7 days, 15 days, and 21 days continued to reduce dopamine neuron population activity. Both acute and repeated effects on population activity were reversed by acute apomorphine injections, which is consistent with the reversal of dopamine neuron depolarization block. Although this action may account for the effects of D2 antagonist drugs on alleviating psychosis and the lack of development of tolerance in humans, the drugs appear to do so by inducing an offsetting deficit rather than attacking the primary pathology present in schizophrenia. PMID:21865475

  2. Impairments and compensation in mouth and limb use in free feeding after unilateral dopamine depletions in a rat analog of human Parkinson's disease.

    PubMed

    Whishaw, I Q; Coles, B L; Pellis, S M; Miklyaeva, E I

    1997-03-01

    Rats depleted unilaterally of dopamine (DA) with the neurotoxin 6-hydroxydopamine (6-OHDA) have contralateral sensorimotor deficits. These include pronounced impairments in using the contralateral limbs (bad limbs) for skilled movements in tests of reaching and bar pressing. There has been no systematic examination of the changes that take place in movements of spontaneous food handling. This was the purpose of the present study. Rats were filmed as they picked up and ate pieces of angel hair pasta (Capelli d'Angelo), a food item that challenges the rats to use delicate and bilaterally coordinated limb and paw movements. Control rats picked up the food with their incisors, transferred it to their paws, and manipulated it using a variety of bilaterally coordinated limb and paw movements. The DA-depleted rats were impaired in both their mouth and paw movements. They seemed unable to use their teeth to grasp the food and so used their tongue. They did not use the bad side of their mouth to chew and relied upon the good side of their mouth. The bad paw was impaired in grasping the food, grasped only with a whole paw grip, did not make manipulatory movements, and did not open to release the food or open to regain support once the food was eaten. Although the rats improved over a 30-day recovery period, much of the improvement was due to compensatory adjustments. That unilateral DA-depletion results in profound contralateral impairments of the mouth and limb with improvements due mainly to compensatory adjustments confirms a role for dopaminergic systems in motor control. Additionally, the behavioral tests described here could provide important adjuncts for assessing therapies in this animal analog of human Parkinson's disease. PMID:9079783

  3. Cannabis induced dopamine release: an in-vivo SPECT study.

    PubMed

    Voruganti, L N; Slomka, P; Zabel, P; Mattar, A; Awad, A G

    2001-10-01

    In a research study aimed at examining the alterations in dopaminergic function in schizophrenia, the authors identified a surreptitious case scenario which provided new insights into the subjective and neurochemical effects of cannabis. A 38-year-old drug-free schizophrenic patient took part in a single photon emission computerized tomographic (SPECT) study of the brain, and smoked cannabis secretively during a pause in the course of an imaging session. Cannabis had an immediate calming effect, followed by a worsening of psychotic symptoms a few hours later. A comparison of the two sets of images, obtained before and immediately after smoking cannabis, indicated a 20% decrease in the striatal dopamine D2 receptor binding ratio, suggestive of increased synaptic dopaminergic activity. This observation offers a plausible biological explanation for the psychotogenic effects of cannabis in vulnerable individuals, and also raises speculations about an interaction between cannabinoid and dopaminergic systems in the brain reward pathways. PMID:11566433

  4. An amperometric nanobiosensor for the selective detection of K?-induced dopamine released from living cells.

    PubMed

    Mir, Tanveer Ahmad; Akhtar, Mahmood H; Gurudatt, N G; Kim, Jeong-In; Choi, Cheol Soo; Shim, Yoon-Bo

    2015-06-15

    A highly sensitive amperometric sensor has been studied for selective monitoring of K(+)-induced dopamine released from dopaminergic cells (PC12) which is based on an EDTA immobilized-poly(1,5-diaminonaphthalne) (poly-DAN) layer comprising graphene oxide (GO) and gold nanoparticles (GO/AuNPs). The integration of a negatively charged probe molecule on the poly-DAN/GO/AuNPs nanohybrid attained the signal enhancement to discriminate dopamine (DA) molecules from foreign species by catalytic effect and surface charge, and hydrogen bonding-based interactions with a probe molecule. The sensor performance and morphology were investigated using voltammetry, impedance spectrometry, SEM, and XPS. Experimental variables affecting the analytical performance of the sensor probe were optimized, and linear response was observed in the range of 10 nM-1 M with a detection limit of 5.0 nM (0.01) for DA. Then, the sensor was applied to monitor dopamine released from PC12 cells upon extracellular stimulation of K(+) ions. It was also confirmed that K(+)-induced dopamine release was inhibited by a calcium channel inhibitor (Nifidipine). The results demonstrated that the presented biosensor could be used as an excellent tool for monitoring the effect of exogenous agents on living cells and drug efficacy tests. PMID:25617752

  5. Multiple functions of Na/K-ATPase in dopamine-induced salivation of the Blacklegged tick, Ixodes scapularis.

    PubMed

    Kim, Donghun; Urban, Joshua; Boyle, Daniel L; Park, Yoonseong

    2016-01-01

    Control of salivary secretion in ticks involves autocrine dopamine activating two dopamine receptors: D1 and Invertebrate-specific D1-like dopamine receptors. In this study, we investigated Na/K-ATPase as an important component of the secretory process. Immunoreactivity for Na/K-ATPase revealed basal infolding of lamellate cells in type-I, abluminal interstitial (epithelial) cells in type-II, and labyrinth-like infolding structures opening towards the lumen in type-III acini. Ouabain (10??mol l(-1)), a specific inhibitor of Na/K-ATPase, abolished dopamine-induced salivary secretion by suppressing fluid transport in type III acini. At 1??mol l(-1), ouabain, the secreted saliva was hyperosmotic. This suggests that ouabain also inhibits an ion resorptive function of Na/K-ATPase in the type I acini. Dopamine/ouabain were not involved in activation of protein secretion, while dopamine-induced saliva contained constitutively basal level of protein. We hypothesize that the dopamine-dependent primary saliva formation, mediated by Na/K-ATPase in type III and type II acini, is followed by a dopamine-independent resorptive function of Na/K-ATPase in type I acini located in the proximal end of the salivary duct. PMID:26861075

  6. Multiple functions of Na/K-ATPase in dopamine-induced salivation of the Blacklegged tick, Ixodes scapularis

    PubMed Central

    Kim, Donghun; Urban, Joshua; Boyle, Daniel L.; Park, Yoonseong

    2016-01-01

    Control of salivary secretion in ticks involves autocrine dopamine activating two dopamine receptors: D1 and Invertebrate-specific D1-like dopamine receptors. In this study, we investigated Na/K-ATPase as an important component of the secretory process. Immunoreactivity for Na/K-ATPase revealed basal infolding of lamellate cells in type-I, abluminal interstitial (epithelial) cells in type-II, and labyrinth-like infolding structures opening towards the lumen in type-III acini. Ouabain (10 μmol l−1), a specific inhibitor of Na/K-ATPase, abolished dopamine-induced salivary secretion by suppressing fluid transport in type III acini. At 1 μmol l−1, ouabain, the secreted saliva was hyperosmotic. This suggests that ouabain also inhibits an ion resorptive function of Na/K-ATPase in the type I acini. Dopamine/ouabain were not involved in activation of protein secretion, while dopamine-induced saliva contained constitutively basal level of protein. We hypothesize that the dopamine-dependent primary saliva formation, mediated by Na/K-ATPase in type III and type II acini, is followed by a dopamine-independent resorptive function of Na/K-ATPase in type I acini located in the proximal end of the salivary duct. PMID:26861075

  7. Amphetamine-Induced Dopamine Release and Neurocognitive Function in Treatment-Naive Adults with ADHD

    PubMed Central

    Cherkasova, Mariya V; Faridi, Nazlie; Casey, Kevin F; O'Driscoll, Gillian A; Hechtman, Lily; Joober, Ridha; Baker, Glen B; Palmer, Jennifer; Dagher, Alain; Leyton, Marco; Benkelfat, Chawki

    2014-01-01

    Converging evidence from clinical, preclinical, neuroimaging, and genetic research implicates dopamine neurotransmission in the pathophysiology of attention deficit hyperactivity disorder (ADHD). The in vivo neuroreceptor imaging evidence also suggests alterations in the dopamine system in ADHD; however, the nature and behavioral significance of those have not yet been established. Here, we investigated striatal dopaminergic function in ADHD using [11C]raclopride PET with a d-amphetamine challenge. We also examined the relationship of striatal dopamine responses to ADHD symptoms and neurocognitive function. A total of 15 treatment-free, noncomorbid adult males with ADHD (age: 29.87±8.65) and 18 healthy male controls (age: 25.44±6.77) underwent two PET scans: one following a lactose placebo and the other following d-amphetamine (0.3 mg/kg, p.o.), administered double blind and in random order counterbalanced across groups. In a separate session without a drug, participants performed a battery of neurocognitive tests. Relative to the healthy controls, the ADHD patients, as a group, showed greater d-amphetamine-induced decreases in striatal [11C]raclopride binding and performed more poorly on measures of response inhibition. Across groups, a greater magnitude of d-amphetamine-induced change in [11C]raclopride binding potential was associated with poorer performance on measures of response inhibition and ADHD symptoms. Our findings suggest an augmented striatal dopaminergic response in treatment-naive ADHD. Though in contrast to results of a previous study, this finding appears consistent with a model proposing exaggerated phasic dopamine release in ADHD. A susceptibility to increased phasic dopamine responsivity may contribute to such characteristics of ADHD as poor inhibition and impulsivity. PMID:24378745

  8. PINK1 heterozygous mutations induce subtle alterations in dopamine-dependent synaptic plasticity

    PubMed Central

    Madeo, G.; Schirinzi, T.; Martella, G.; Latagliata, E.C.; Puglisi, F.; Shen, J.; Valente, E.M.; Federici, M.; Mercuri, N.B.; Puglisi-Allegra, S.; Bonsi, P.; Pisani, A.

    2014-01-01

    Background Homozygous or compound heterozygous mutations in the PTEN-induced kinase 1 (PINK1) gene are causative of autosomal recessive, early onset PD. Single heterozygous mutations have been repeatedly detected in a subset of patients as well as in non-affected subjects, and their significance has long been debated. Several neurophysiological studies from non-manifesting PINK1 heterozygotes have shown the existence of neural plasticity abnormalities, indicating the presence of specific endophenotypic traits in the heterozygous state. Methods In the present study, we performed a functional analysis of corticostriatal synaptic plasticity in heterozygous PINK1 knock-out (PINK1+/?) mice by a multidisciplinary approach. Results We found that, despite a normal motor behavior, repetitive activation of cortical inputs to striatal neurons failed to induce long-term potentiation (LTP), whereas long-term depression (LTD) was normal. Although nigral dopaminergic neurons exhibited normal morphological and electrophysiological properties with normal responses to dopamine receptor activation, we measured a significantly lower dopamine release in the striatum of PINK1+/?, compared to control mice, suggesting that a decrease in stimulus-evoked dopamine overflow acts as a major determinant for the LTP deficit. Accordingly, pharmacological agents capable of increasing the availability of dopamine in the synaptic cleft restored a normal LTP in heterozygous mice. Moreover, MAO-B inhibitors rescued a physiological LTP and a normal dopamine release. Conclusions Our results provide novel evidence for striatal plasticity abnormalities even in the heterozygous disease state. These alterations might be considered an endophenotype to this monogenic form of PD, and a valid tool to characterize early disease stage and design possible disease-modifying therapies. PMID:24167038

  9. Copper dopamine complex induces mitochondrial autophagy preceding caspase-independent apoptotic cell death.

    PubMed

    Paris, Irmgard; Perez-Pastene, Carolina; Couve, Eduardo; Caviedes, Pablo; Ledoux, Susan; Segura-Aguilar, Juan

    2009-05-15

    Parkinsonism is one of the major neurological symptoms in Wilson disease, and young workers who worked in the copper smelting industry also developed Parkinsonism. We have reported the specific neurotoxic action of copper dopamine complex in neurons with dopamine uptake. Copper dopamine complex (100 microm) induces cell death in RCSN-3 cells by disrupting the cellular redox state, as demonstrated by a 1.9-fold increase in oxidized glutathione levels and a 56% cell death inhibition in the presence of 500 microm ascorbic acid; disruption of mitochondrial membrane potential with a spherical shape and well preserved morphology determined by transmission electron microscopy; inhibition (72%, p < 0.001) of phosphatidylserine externalization with 5 microm cyclosporine A; lack of caspase-3 activation; formation of autophagic vacuoles containing mitochondria after 2 h; transfection of cells with green fluorescent protein-light chain 3 plasmid showing that 68% of cells presented autophagosome vacuoles; colocalization of positive staining for green fluorescent protein-light chain 3 and Rhod-2AM, a selective indicator of mitochondrial calcium; and DNA laddering after 12-h incubation. These results suggest that the copper dopamine complex induces mitochondrial autophagy followed by caspase-3-independent apoptotic cell death. However, a different cell death mechanism was observed when 100 microm copper dopamine complex was incubated in the presence of 100 microm dicoumarol, an inhibitor of NAD(P)H quinone:oxidoreductase (EC 1.6.99.2, also known as DT-diaphorase and NQ01), because a more extensive and rapid cell death was observed. In addition, cyclosporine A had no effect on phosphatidylserine externalization, significant portions of compact chromatin were observed within a vacuolated nuclear membrane, DNA laddering was less pronounced, the mitochondria morphology was more affected, and the number of cells with autophagic vacuoles was a near 4-fold less. PMID:19265190

  10. Copper·Dopamine Complex Induces Mitochondrial Autophagy Preceding Caspase-independent Apoptotic Cell Death*

    PubMed Central

    Paris, Irmgard; Perez-Pastene, Carolina; Couve, Eduardo; Caviedes, Pablo; LeDoux, Susan; Segura-Aguilar, Juan

    2009-01-01

    Parkinsonism is one of the major neurological symptoms in Wilson disease, and young workers who worked in the copper smelting industry also developed Parkinsonism. We have reported the specific neurotoxic action of copper·dopamine complex in neurons with dopamine uptake. Copper·dopamine complex (100 μm) induces cell death in RCSN-3 cells by disrupting the cellular redox state, as demonstrated by a 1.9-fold increase in oxidized glutathione levels and a 56% cell death inhibition in the presence of 500 μm ascorbic acid; disruption of mitochondrial membrane potential with a spherical shape and well preserved morphology determined by transmission electron microscopy; inhibition (72%, p < 0.001) of phosphatidylserine externalization with 5 μm cyclosporine A; lack of caspase-3 activation; formation of autophagic vacuoles containing mitochondria after 2 h; transfection of cells with green fluorescent protein-light chain 3 plasmid showing that 68% of cells presented autophagosome vacuoles; colocalization of positive staining for green fluorescent protein-light chain 3 and Rhod-2AM, a selective indicator of mitochondrial calcium; and DNA laddering after 12-h incubation. These results suggest that the copper·dopamine complex induces mitochondrial autophagy followed by caspase-3-independent apoptotic cell death. However, a different cell death mechanism was observed when 100 μm copper·dopamine complex was incubated in the presence of 100 μm dicoumarol, an inhibitor of NAD(P)H quinone:oxidoreductase (EC 1.6.99.2, also known as DT-diaphorase and NQ01), because a more extensive and rapid cell death was observed. In addition, cyclosporine A had no effect on phosphatidylserine externalization, significant portions of compact chromatin were observed within a vacuolated nuclear membrane, DNA laddering was less pronounced, the mitochondria morphology was more affected, and the number of cells with autophagic vacuoles was a near 4-fold less. PMID:19265190

  11. PINK1 heterozygous mutations induce subtle alterations in dopamine-dependent synaptic plasticity.

    PubMed

    Madeo, Graziella; Schirinzi, Tommaso; Martella, Giuseppina; Latagliata, E Claudio; Puglisi, Francesca; Shen, Jie; Valente, Enza Maria; Federici, Mauro; Mercuri, Nicola B; Puglisi-Allegra, Stefano; Bonsi, Paola; Pisani, Antonio

    2014-01-01

    Homozygous or compound heterozygous mutations in the phosphatase and tensin homolog-induced putative kinase 1 (PINK1) gene are causative of autosomal recessive, early onset Parkinson's disease. Single heterozygous mutations have been detected repeatedly both in a subset of patients and in unaffected individuals, and the significance of these mutations has long been debated. Several neurophysiological studies from non-manifesting PINK1 heterozygotes have demonstrated the existence of neural plasticity abnormalities, indicating the presence of specific endophenotypic traits in the heterozygous state. We performed a functional analysis of corticostriatal synaptic plasticity in heterozygous PINK1 knockout (PINK1(+/-) ) mice using a multidisciplinary approach and observed that, despite normal motor behavior, repetitive activation of cortical inputs to striatal neurons failed to induce long-term potentiation (LTP), whereas long-term depression was normal. Although nigral dopaminergic neurons exhibited normal morphological and electrophysiological properties with normal responses to dopamine receptor activation, a significantly lower dopamine release was measured in the striatum of PINK1(+/-) mice compared with control mice, suggesting that a decrease in stimulus-evoked dopamine overflow acts as a major determinant for the LTP deficit. Accordingly, pharmacological agents capable of increasing the availability of dopamine in the synaptic cleft restored normal LTP in heterozygous mice. Moreover, monoamine oxidase B inhibitors rescued physiological LTP and normal dopamine release. Our results provide novel evidence for striatal plasticity abnormalities, even in the heterozygous disease state. These alterations might be considered an endophenotype to this monogenic form of Parkinson's disease and a valid tool with which to characterize early disease stage and design possible disease-modifying therapies. PMID:24167038

  12. Recovery of striatal dopamine function after acute amphetamine- and methamphetamine-induced neurotoxicity in the vervet monkey.

    PubMed

    Melega, W P; Raleigh, M J; Stout, D B; Lacan, G; Huang, S C; Phelps, M E

    1997-08-22

    In six vervet monkeys, presynaptic striatal dopamine function was assessed longitudinally by [18F]fluoro-L-DOPA (FDOPA)-positron emission tomography (PET) after administration (2 x 2 mg/kg, i.m., 4 h apart) of either amphetamine (Amp), n = 3, or methamphetamine (MeAmp), n = 3. At 1-2 weeks postdrug, both Amp and MeAmp exposure effected similar decreases (60-70%) in the FDOPA influx rate constant (FDOPA Ki), an index of striatal dopamine synthesis capacity. Subsequent studies in these subjects showed that FDOPA Ki values were decreased by 45-67% at 3-6 weeks, by 25% at 10-12 weeks and by 16% in one Amp-treated subject at 32 weeks. Biochemical analysis showed that striatal dopamine concentrations were decreased by 75% at 3-4 weeks and by 55% at 10-12 weeks. These results indicate that in vervet monkey striatum, an acute Amp or MeAmp drug dosage produces extensive striatal dopamine system neurotoxicity. However, these effects were reversible; observed time-dependent recovery in both FDOPA Ki and dopamine concentrations indicates that neurochemical plasticity remains active in the adult primate striatum. At 3-4 and 10-12 weeks postdrug, the concurrent characterization of the striatal FDOPA Ki and dopamine concentrations for individual subjects showed that Ki decreases between 24 and 67% corresponded to dopamine depletions of 55-85%. These relatively larger postdrug decrements in steady-state striatal dopamine concentrations suggest that compensatory increases in dopamine synthesis capacity develop in the partially lesioned striatum. In contrast to the dopamine depletion in striatum, substantia nigra concentrations remained unchanged from referent values at both 3-4 and 10-12 weeks postdrug. Thus, the integrity of the substantia nigra could not be inferred from decreases in the striatal FDOPA Ki parameter. This disparity between striatum and substantia nigra reactivity to systemic administration of amphetamines suggests that each has unique dopamine system regulatory mechanisms. PMID:9359594

  13. Shock induced multi-mode damage in depleted uranium

    SciTech Connect

    Koller, Darcie D; Cerreta, Ellen K; Gray, Ill, George T

    2009-01-01

    Recent dynamic damage studies on depleted uranium samples have revealed mixed mode failure mechanisms leading to incipient cracking as well as ductile failure processes. Results show that delamination of inclusions upon compression may provide nucleation sites for damage initiation in the form of crack tip production. However, under tension the material propagates cracks in a mixed shear localization and mode-I ductile tearing and cracking. Cracks tips appear to link up through regions of severe, shear dominated plastic flow. Shock recovery experiments were conducted on a 50 mm single stage light gas gun. Serial metallographic sectioning was conducted on the recovered samples to characterize the bulk response of the sample. Experiments show delaminated inclusions due to uniaxial compression without damage propagation. Further results show the propagation of the damage through tensile loading to the incipient state, illustrating ductile processes coupled with mixed mode-I tensile ductile tearing, shear localization, and mode-I cracking in depleted uranium.

  14. A search for relativistic electron induced stratospheric ozone depletion

    NASA Technical Reports Server (NTRS)

    Aikin, Arthur C.

    1994-01-01

    Possible ozone changes at 1 mb associated with the time variation and precipitation of relativistic electrons are investigated by examining the NIMBUS 7 SBUV ozone data set and corresponding temperatures derived from NMC data. No ozone depletion was observed in high-latitude summer when temperature fluctuations are small. In winter more variation in ozone occurs, but large temperature changes make it difficult to identify specific ozone decreases as being the result of relativistic electron precipitation.

  15. A role for D1 dopamine receptors in striatal methamphetamine-induced neurotoxicity.

    PubMed

    Friend, Danielle M; Keefe, Kristen A

    2013-10-25

    Methamphetamine (METH) exposure results in long-term damage to the dopamine system in both human METH abusers and animal models. One factor that has been heavily implicated in this METH-induced damage to the dopaminergic system is the activation of D1 dopamine (DA) receptors. However, a significant caveat to the studies investigating the role of the receptor in such toxicity is that genetic and pharmacological manipulations of the D1 DA receptor also mitigate METH-induced hyperthermia. Importantly, METH-induced hyperthermia is tightly associated with the neurotoxicity, such that simply cooling animals during METH exposure protects against the neurotoxicity. Therefore, it is difficult to determine whether D1 DA receptors per se play an important role in METH-induced neurotoxicity or whether the protection observed simply resulted from a mitigation of METH-induced hyperthermia. To answer this important question, the current study infused a D1 DA receptor antagonist into striatum during METH exposure while controlling for METH-induced hyperthermia. Here we found that even when METH-induced hyperthermia is maintained, the coadministration of a D1 DA receptor antagonist protects against METH-induced neurotoxicity, strongly suggesting that D1 DA receptors play an important role in METH-induced neurotoxicity apart from the mitigation of METH-induced hyperthermia. PMID:23994061

  16. Depletion flocculation induced by synergistic effects of nanoparticles and polymers.

    PubMed

    Ji, Shunxi; Walz, John Y

    2013-12-27

    The depletion flocculation of stable suspensions of charged microparticles (1.2 ?m diameter polystyrene) by mixtures of silica nanoparticles (7 nm) and poly(acrylic) acid (PAA, Mn = 24?500) was studied. The experiments revealed a very clear critical flocculation concentration of PAA that was lowered by the addition of the silica nanoparticles. Equilibrium pair potentials between the particles, calculated from force profiles measured between a silica particle and plate using colloid probe atomic force microscopy, showed clear a synergistic effect in that the magnitude of the depletion and structural forces produced in the mixed PAA/nanoparticle system was significantly greater than the sum of the forces in systems containing only PAA or only nanoparticles. This effect arises from adsorption of the PAA onto the nanoparticles, creating much larger charged complexes. Comparing the calculated pair potentials to the observed flocculation results revealed that flocculation occurred once the magnitude of the secondary energy well formed by the attractive depletion force exceeded 5 kT. PMID:24328046

  17. Dopamine D3 receptor antagonism contributes to blonanserin-induced cortical dopamine and acetylcholine efflux and cognitive improvement.

    PubMed

    Huang, Mei; Kwon, Sunoh; Oyamada, Yoshihiro; Rajagopal, Lakshmi; Miyauchi, Masanori; Meltzer, Herbert Y

    2015-11-01

    Blonanserin is a novel atypical antipsychotic drug (APD), which, unlike most atypical APDs, has a slightly higher affinity for dopamine (DA) D2 than serotonin (5-HT)2A receptors, and is an antagonist at both, as well as at D3 receptors. The effects of atypical APDs to enhance rodent cortical, hippocampal, limbic, and dorsal striatal (dSTR) DA and acetylcholine (ACh) release, contribute to their ability to improve novel object recognition (NOR) in rodents treated with sub-chronic (sc) phencyclidine (PCP) and cognitive impairment associated with schizophrenia (CIAS). Here we determined the ability of blonanserin, the D3 antagonist NGB 2904, and the typical APD, haloperidol, a D2 antagonist, to enhance neurotransmitter efflux in the medial prefrontal cortex (mPFC) and dSTR of mice, and to ameliorate the scPCP-induced deficit in NOR in rats. Blonanserin, 10mg/kg, i.p., increased DA, norepinephrine (NE), and ACh efflux in mPFC and dSTR. NGB 2904, 3mg/kg, increased DA and ACh, but not NE, efflux in mPFC, and DA, but not ACh, efflux in dSTR. Haloperidol increased DA and NE efflux in dSTR only. The selective D3 agonist PD 128907 partially blocked the blonanserin-induced cortical ACh, DA, NE and striatal DA efflux. NGB 2904, 3mg/kg, like blonanserin, 1mg/kg, and the combination of sub-effective doses of NGB 2904 and blonanserin (both 0.3mg/kg), ameliorated the scPCP-induced NOR deficit in rats. These results suggest that D3 receptor blockade may contribute to the ability of blonanserin to increase cortical DA and ACh efflux, as well as to restore NOR and improve CIAS. PMID:26383990

  18. Coarse-grained molecular dynamics simulations of depletion-induced interactions for soft matter systems

    SciTech Connect

    Shendruk, Tyler N.; Bertrand, Martin; Harden, James L.; Slater, Gary W.; Haan, Hendrick W. de

    2014-12-28

    Given the ubiquity of depletion effects in biological and other soft matter systems, it is desirable to have coarse-grained Molecular Dynamics (MD) simulation approaches appropriate for the study of complex systems. This paper examines the use of two common truncated Lennard-Jones (Weeks-Chandler-Andersen (WCA)) potentials to describe a pair of colloidal particles in a thermal bath of depletants. The shifted-WCA model is the steeper of the two repulsive potentials considered, while the combinatorial-WCA model is the softer. It is found that the depletion-induced well depth for the combinatorial-WCA model is significantly deeper than the shifted-WCA model because the resulting overlap of the colloids yields extra accessible volume for depletants. For both shifted- and combinatorial-WCA simulations, the second virial coefficients and pair potentials between colloids are demonstrated to be well approximated by the Morphometric Thermodynamics (MT) model. This agreement suggests that the presence of depletants can be accurately modelled in MD simulations by implicitly including them through simple, analytical MT forms for depletion-induced interactions. Although both WCA potentials are found to be effective generic coarse-grained simulation approaches for studying depletion effects in complicated soft matter systems, combinatorial-WCA is the more efficient approach as depletion effects are enhanced at lower depletant densities. The findings indicate that for soft matter systems that are better modelled by potentials with some compressibility, predictions from hard-sphere systems could greatly underestimate the magnitude of depletion effects at a given depletant density.

  19. Myc Depletion Induces a Pluripotent Dormant State Mimicking Diapause

    PubMed Central

    Scognamiglio, Roberta; Cabezas-Wallscheid, Nina; Thier, Marc Christian; Altamura, Sandro; Reyes, Alejandro; Prendergast, Áine M.; Baumgärtner, Daniel; Carnevalli, Larissa S.; Atzberger, Ann; Haas, Simon; von Paleske, Lisa; Boroviak, Thorsten; Wörsdörfer, Philipp; Essers, Marieke A.G.; Kloz, Ulrich; Eisenman, Robert N.; Edenhofer, Frank; Bertone, Paul; Huber, Wolfgang; van der Hoeven, Franciscus; Smith, Austin; Trumpp, Andreas

    2016-01-01

    Summary Mouse embryonic stem cells (ESCs) are maintained in a naive ground state of pluripotency in the presence of MEK and GSK3 inhibitors. Here, we show that ground-state ESCs express low Myc levels. Deletion of both c-myc and N-myc (dKO) or pharmacological inhibition of Myc activity strongly decreases transcription, splicing, and protein synthesis, leading to proliferation arrest. This process is reversible and occurs without affecting pluripotency, suggesting that Myc-depleted stem cells enter a state of dormancy similar to embryonic diapause. Indeed, c-Myc is depleted in diapaused blastocysts, and the differential expression signatures of dKO ESCs and diapaused epiblasts are remarkably similar. Following Myc inhibition, pre-implantation blastocysts enter biosynthetic dormancy but can progress through their normal developmental program after transfer into pseudo-pregnant recipients. Our study shows that Myc controls the biosynthetic machinery of stem cells without affecting their potency, thus regulating their entry and exit from the dormant state. PMID:26871632

  20. Myc Depletion Induces a Pluripotent Dormant State Mimicking Diapause.

    PubMed

    Scognamiglio, Roberta; Cabezas-Wallscheid, Nina; Thier, Marc Christian; Altamura, Sandro; Reyes, Alejandro; Prendergast, Áine M; Baumgärtner, Daniel; Carnevalli, Larissa S; Atzberger, Ann; Haas, Simon; von Paleske, Lisa; Boroviak, Thorsten; Wörsdörfer, Philipp; Essers, Marieke A G; Kloz, Ulrich; Eisenman, Robert N; Edenhofer, Frank; Bertone, Paul; Huber, Wolfgang; van der Hoeven, Franciscus; Smith, Austin; Trumpp, Andreas

    2016-02-11

    Mouse embryonic stem cells (ESCs) are maintained in a naive ground state of pluripotency in the presence of MEK and GSK3 inhibitors. Here, we show that ground-state ESCs express low Myc levels. Deletion of both c-myc and N-myc (dKO) or pharmacological inhibition of Myc activity strongly decreases transcription, splicing, and protein synthesis, leading to proliferation arrest. This process is reversible and occurs without affecting pluripotency, suggesting that Myc-depleted stem cells enter a state of dormancy similar to embryonic diapause. Indeed, c-Myc is depleted in diapaused blastocysts, and the differential expression signatures of dKO ESCs and diapaused epiblasts are remarkably similar. Following Myc inhibition, pre-implantation blastocysts enter biosynthetic dormancy but can progress through their normal developmental program after transfer into pseudo-pregnant recipients. Our study shows that Myc controls the biosynthetic machinery of stem cells without affecting their potency, thus regulating their entry and exit from the dormant state. PMID:26871632

  1. Depletion force induced collective motion of microtubules driven by kinesin

    NASA Astrophysics Data System (ADS)

    Inoue, Daisuke; Mahmot, Bulbul; Kabir, Arif Md. Rashedul; Farhana, Tamanna Ishrat; Tokuraku, Kiyotaka; Sada, Kazuki; Konagaya, Akihiko; Kakugo, Akira

    2015-10-01

    Collective motion is a fascinating example of coordinated behavior of self-propelled objects, which is often associated with the formation of large scale patterns. Nowadays, the in vitro gliding assay is being considered a model system to experimentally investigate various aspects of group behavior and pattern formation by self-propelled objects. In the in vitro gliding assay, cytoskeletal filaments F-actin or microtubules are driven by the surface immobilized associated biomolecular motors myosin or dynein respectively. Although the F-actin/myosin or microtubule/dynein system was found to be promising in understanding the collective motion and pattern formation by self-propelled objects, the most widely used biomolecular motor system microtubule/kinesin could not be successfully employed so far in this regard. Failure in exhibiting collective motion by kinesin driven microtubules is attributed to the intrinsic properties of kinesin, which was speculated to affect the behavior of individual gliding microtubules and mutual interactions among them. In this work, for the first time, we have demonstrated the collective motion of kinesin driven microtubules by regulating the mutual interaction among the gliding microtubules, by employing a depletion force among them. Proper regulation of the mutual interaction among the gliding microtubules through the employment of the depletion force was found to allow the exhibition of collective motion and stream pattern formation by the microtubules. This work offers a universal means for demonstrating the collective motion using the in vitro gliding assay of biomolecular motor systems and will help obtain a meticulous understanding of the fascinating coordinated behavior and pattern formation by self-propelled objects.Collective motion is a fascinating example of coordinated behavior of self-propelled objects, which is often associated with the formation of large scale patterns. Nowadays, the in vitro gliding assay is being considered a model system to experimentally investigate various aspects of group behavior and pattern formation by self-propelled objects. In the in vitro gliding assay, cytoskeletal filaments F-actin or microtubules are driven by the surface immobilized associated biomolecular motors myosin or dynein respectively. Although the F-actin/myosin or microtubule/dynein system was found to be promising in understanding the collective motion and pattern formation by self-propelled objects, the most widely used biomolecular motor system microtubule/kinesin could not be successfully employed so far in this regard. Failure in exhibiting collective motion by kinesin driven microtubules is attributed to the intrinsic properties of kinesin, which was speculated to affect the behavior of individual gliding microtubules and mutual interactions among them. In this work, for the first time, we have demonstrated the collective motion of kinesin driven microtubules by regulating the mutual interaction among the gliding microtubules, by employing a depletion force among them. Proper regulation of the mutual interaction among the gliding microtubules through the employment of the depletion force was found to allow the exhibition of collective motion and stream pattern formation by the microtubules. This work offers a universal means for demonstrating the collective motion using the in vitro gliding assay of biomolecular motor systems and will help obtain a meticulous understanding of the fascinating coordinated behavior and pattern formation by self-propelled objects. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr02213d

  2. The ovarian DNA damage repair response is induced prior to phosphoramide mustard-induced follicle depletion, and ataxia telangiectasia mutated inhibition prevents PM-induced follicle depletion.

    PubMed

    Ganesan, Shanthi; Keating, Aileen F

    2016-02-01

    Phosphoramide mustard (PM) is an ovotoxic metabolite of cyclophosphamide and destroys primordial and primary follicles potentially by DNA damage induction. The temporal pattern by which PM induces DNA damage and initiation of the ovarian response to DNA damage has not yet been well characterized. This study investigated DNA damage initiation, the DNA repair response, as well as induction of follicular demise using a neonatal rat ovarian culture system. Additionally, to delineate specific mechanisms involved in the ovarian response to PM exposure, utility was made of PKC delta (PKC?) deficient mice as well as an ATM inhibitor (KU 55933; AI). Fisher 344 PND4 rat ovaries were cultured for 12, 24, 48 or 96h in medium containing DMSO 60?M PM or KU 55933 (48h; 10nM). PM-induced activation of DNA damage repair genes was observed as early as 12h post-exposure. ATM, PARP1, E2F7, P73 and CASP3 abundance were increased but RAD51 and BCL2 protein decreased after 96h of PM exposure. PKC? deficiency reduced numbers of all follicular stages, but did not have an additive impact on PM-induced ovotoxicity. ATM inhibition protected all follicle stages from PM-induced depletion. In conclusion, the ovarian DNA damage repair response is active post-PM exposure, supporting that DNA damage contributes to PM-induced ovotoxicity. PMID:26708502

  3. Depletion force induced collective motion of microtubules driven by kinesin.

    PubMed

    Inoue, Daisuke; Mahmot, Bulbul; Kabir, Arif Md Rashedul; Farhana, Tamanna Ishrat; Tokuraku, Kiyotaka; Sada, Kazuki; Konagaya, Akihiko; Kakugo, Akira

    2015-10-29

    Collective motion is a fascinating example of coordinated behavior of self-propelled objects, which is often associated with the formation of large scale patterns. Nowadays, the in vitro gliding assay is being considered a model system to experimentally investigate various aspects of group behavior and pattern formation by self-propelled objects. In the in vitro gliding assay, cytoskeletal filaments F-actin or microtubules are driven by the surface immobilized associated biomolecular motors myosin or dynein respectively. Although the F-actin/myosin or microtubule/dynein system was found to be promising in understanding the collective motion and pattern formation by self-propelled objects, the most widely used biomolecular motor system microtubule/kinesin could not be successfully employed so far in this regard. Failure in exhibiting collective motion by kinesin driven microtubules is attributed to the intrinsic properties of kinesin, which was speculated to affect the behavior of individual gliding microtubules and mutual interactions among them. In this work, for the first time, we have demonstrated the collective motion of kinesin driven microtubules by regulating the mutual interaction among the gliding microtubules, by employing a depletion force among them. Proper regulation of the mutual interaction among the gliding microtubules through the employment of the depletion force was found to allow the exhibition of collective motion and stream pattern formation by the microtubules. This work offers a universal means for demonstrating the collective motion using the in vitro gliding assay of biomolecular motor systems and will help obtain a meticulous understanding of the fascinating coordinated behavior and pattern formation by self-propelled objects. PMID:26260025

  4. Neuroleptic-induced striatal dopamine receptor supersensitivity in mice: relationship to dose and drug.

    PubMed

    Severson, J A; Robinson, H E; Simpson, G M

    1984-01-01

    Clozapine and molindone administered to mice for 21 days did not elevate the density of striatal 3H-spiperone binding sites at doses clinically equivalent to 1.5 mg/kg haloperidol, which elevated binding by 29%. Thioridazine (25 mg/kg) elevated binding by 25%. It appears that clinically equivalent doses of clozapine and molindone have reduced ability to induce striatal D-2 dopamine receptor supersensitivity. These data are discussed in relationship to in vitro potencies and toxicity. The dose-response relationship of chronic haloperidol treatment and specific striatal 3H-spiperone binding was complex, i.e., binding was elevated at all doses, but the dose-response curve was concave upward. These data suggest that supersensitization is a complex interactive phenomenon comprised of elevation of striatal D-2 dopamine receptor density and other compensatory mechanisms. PMID:6149590

  5. Antagonism of bromocriptine-induced cage climbing behaviour in mice by the selective D-2 dopamine receptor antagonists, metoclopramide and molindone.

    PubMed

    Balsara, J J; Nandal, N V; Gada, V P; Bapat, T R; Chandorkar, A G

    1986-01-01

    Bromocriptine (5-30 mg/kg, ip), 2 hr after administration, induced cage climbing behaviour in mice. Pretreatment with haloperidol, an antagonist of both D-1 and D-2 dopamine receptors, metoclopramide and molindone, the selective D-2 dopamine receptor antagonists, effectively antagonised bromocriptine-induced climbing behaviour. The results indicate that bromocriptine most probably induces climbing behaviour in mice by stimulating the postsynaptic striatal D-2 dopamine receptors. PMID:2950056

  6. Differential subcellular distribution of rat brain dopamine receptors and subtype-specific redistribution induced by cocaine

    PubMed Central

    Voulalas, Pamela J.; Schetz, John; Undieh, Ashiwel S.

    2011-01-01

    We investigated the subcellular distribution of dopamine D1, D2 and D5 receptor subtypes in rat frontal cortex, and examined whether psychostimulant-induced elevation of synaptic dopamine could alter the receptor distribution. Differential detergent solubilization and density gradient centrifugation were used to separate various subcellular fractions, followed by semi-quantitative determination of the relative abundance of specific receptor proteins in each fraction. D1 receptors were predominantly localized to detergent-resistant membranes, and a portion of these receptors also floated on sucrose gradients. These properties are characteristic of proteins found in lipid rafts and caveolae. D2 receptors exhibited variable distribution between cytoplasmic, detergent-soluble and detergent-resistant membrane fractions, yet were not present in buoyant membranes. Most D5 receptor immunoreactivity was distributed into the cytoplasmic fraction, failing to sediment at forces up to 300,000g, while the remainder was localized to detergent-soluble membranes in cortex. D5 receptors were undetectable in detergent-resistant fractions or raft-like subdomains. Following daily cocaine administration for seven days, a significant portion of D1 receptors translocated from detergent-resistant membranes to detergent-soluble membranes and the cytoplasmic fraction. The distributions of D5 and D2 receptor subtypes were not significantly altered by cocaine treatment. These data imply that D5 receptors are predominantly cytoplasmic, D2 receptors are diffusely distributed within the cell, whereas D1 receptors are mostly localized to lipid rafts within the rat frontal cortex. Dopamine receptor subtype localization is susceptible to modulation by pharmacological manipulations that elevate synaptic dopamine, however the functional implications of such drug-induced receptor warrant further investigation. PMID:21236347

  7. Limonene inhibits methamphetamine-induced locomotor activity via regulation of 5-HT neuronal function and dopamine release.

    PubMed

    Yun, Jaesuk

    2014-05-15

    Methamphetamine is a psychomotor stimulant that produces hyperlocomotion in rodents. Limonene (a cyclic terpene from citrus essential oils) has been reported to induce sedative effects. In this study, we demonstrated that limonene administration significantly inhibited serotonin (5-hydroxytryptamine, 5-HT)-induced head twitch response in mice. In rats, pretreatment with limonene decreased hyperlocomotion induced by methamphetamine injection. In addition, limonene reversed the increase in dopamine levels in the nucleus accumbens of rats given methamphetamine. These results suggest that limonene may inhibit stimulant-induced behavioral changes via regulating dopamine levels and 5-HT receptor function. PMID:24462212

  8. BDNF Interacts with Endocannabinoids to Regulate Cocaine-Induced Synaptic Plasticity in Mouse Midbrain Dopamine Neurons

    PubMed Central

    Zhong, Peng; Liu, Yong; Hu, Ying; Wang, Tong; Zhao, Yong-ping

    2015-01-01

    Brain-derived neurotrophic factor (BDNF) and endocannabinoids (eCBs) have been individually implicated in behavioral effects of cocaine. The present study examined how BDNF-eCB interaction regulates cocaine-induced synaptic plasticity in the ventral tegmental area and behavioral effects. We report that BDNF and selective tyrosine kinase receptor B (TrkB) agonist 7,8-dihydroxyflavone (DHF) activated the TrkB receptor to facilitate two forms of eCB-mediated synaptic depression, depolarization-induced suppression of inhibition (DSI), and long-term depression (I-LTD) of IPSCs in ventral tegmental area dopamine neurons in mouse midbrain slices. The facilitation appears to be mediated by an increase in eCB production via phospholipase C? pathway, but not by an increase in CB1 receptor responsiveness or a decrease in eCB hydrolysis. Using Cre-loxP technology to specifically delete BDNF in dopamine neurons, we showed that eCB-mediated I-LTD, cocaine-induced reduction of GABAergic inhibition, and potentiation of glutamatergic excitation remained intact in wild-type control mice, but were impaired in BDNF conditional knock-out mice. We also showed that cocaine-induced conditioned place preference was attenuated in BDNF conditional knock-out mice, in vivo pretreatments with DHF before place conditioning restored cocaine conditioned place preference in these mice, and the behavioral effect of DHF was blocked by a CB1 receptor antagonist. Together, these results suggest that BDNF in dopamine neurons regulates eCB responses, cocaine-induced synaptic plasticity, and associative learning. PMID:25762688

  9. Effects of Acute Tryptophan Depletion on Brain Serotonin Function and Concentrations of Dopamine and Norepinephrine in C57BL/6J and BALB/cJ Mice

    PubMed Central

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

    2012-01-01

    Acute tryptophan depletion (ATD) is a method of lowering brain serotonin (5-HT). Administration of large neutral amino acids (LNAA) limits the transport of endogenous tryptophan (TRP) across the blood brain barrier by competition with other LNAAs and subsequently decreases serotonergic neurotransmission. A recent discussion on the specificity and efficacy of the ATD paradigm for inhibition of central nervous 5-HT has arisen. Moreover, side effects such as vomiting and nausea after intake of amino acids (AA) still limit its use. ATD Moja-De is a revised mixture of AAs which is less nauseating than conventional protocols. It has been used in preliminary clinical studies but its effects on central 5-HT mechanisms and other neurotransmitter systems have not been validated in an animal model. We tested ATD Moja-De (TRP?) in two strains of mice: C57BL/6J, and BALB/cJ, which are reported to have impaired 5-HT synthesis and a more anxious phenotype relative to other strains of mice. ATD Moja-De lowered brain TRP, significantly decreased 5-HT synthesis as indexed by 5-HTP levels after decarboxlyase inhibition, and lowered 5-HT and 5-HIAA in both strains of mice, however more so in C57BL/6J than in BALB/cJ. Dopamine and its metabolites as well as norepinephrine were not affected. A balanced (TRP+) control mixture did not raise 5-HT or 5-HIAA. The present findings suggest that ATD Moja-De effectively and specifically suppresses central serotonergic function. These results also demonstrate a strain- specific effect of ATD Moja-De on anxiety-like behavior. PMID:22629305

  10. Auranofin induces apoptosis and necrosis in HeLa cells via oxidative stress and glutathione depletion.

    PubMed

    You, Bo Ra; Shin, Hye Rim; Han, Bo Ram; Kim, Suhn Hee; Park, Woo Hyun

    2015-02-01

    Auranofin (Au), an inhibitor of thioredoxin reductase, is a known anti?cancer drug. In the present study, the anti?growth effect of Au on HeLa cervical cancer cells was examined in association with levels of reactive oxygen species (ROS) and glutathione (GSH). Au inhibited the growth of HeLa cells with an IC50 of ~2 M at 24 h. This agent induced apoptosis and necrosis, accompanied by the cleavage of poly (ADP?ribose) polymerase and loss of mitochondrial membrane potential. The pan?caspase inhibitor, benzyloxycarbonyl?Val?Ala?Asp?fluoromethylketone, prevented apoptotic cell death and each of the assessed caspase inhibitors inhibited necrotic cell death induced by Au. With respect to the levels of ROS and GSH, Au increased intracellular O2- in the HeLa cells and induced GSH depletion. The pan?caspase inhibitor reduced the levels of O2- and GSH depletion in Au?treated HeLa cells. The antioxidant, N?acetyl cysteine, not only attenuated apoptosis and necrosis in the Au?treated HeLa cells, but also decreased the levels of O2- and GSH depletion in the cells. By contrast, L?buthionine sulfoximine, a GSH synthesis inhibitor, intensified cell death O2- and GSH depletion in the Au?treated HeLa cells. In conclusion, Au induced apoptosis and necrosis in HeLa cells via the induction of oxidative stress and the depletion of GSH. PMID:25370167

  11. Kappa Opioid Receptor-Induced Aversion Requires p38 MAPK Activation in VTA Dopamine Neurons

    PubMed Central

    Ehrich, Jonathan M.; Messinger, Daniel I.; Knakal, Cerise R.; Kuhar, Jamie R.; Schattauer, Selena S.; Bruchas, Michael R.; Zweifel, Larry S.; Kieffer, Brigitte L.; Phillips, Paul E.M.

    2015-01-01

    The endogenous dynorphin-κ opioid receptor (KOR) system encodes the dysphoric component of the stress response and controls the risk of depression-like and addiction behaviors; however, the molecular and neural circuit mechanisms are not understood. In this study, we report that KOR activation of p38α MAPK in ventral tegmental (VTA) dopaminergic neurons was required for conditioned place aversion (CPA) in mice. Conditional genetic deletion of floxed KOR or floxed p38α MAPK by Cre recombinase expression in dopaminergic neurons blocked place aversion to the KOR agonist U50,488. Selective viral rescue by wild-type KOR expression in dopaminergic neurons of KOR−/− mice restored U50,488-CPA, whereas expression of a mutated form of KOR that could not initiate p38α MAPK activation did not. Surprisingly, while p38α MAPK inactivation blocked U50,488-CPA, p38α MAPK was not required for KOR inhibition of evoked dopamine release measured by fast scan cyclic voltammetry in the nucleus accumbens. In contrast, KOR activation acutely inhibited VTA dopaminergic neuron firing, and repeated exposure attenuated the opioid response. This adaptation to repeated exposure was blocked by conditional deletion of p38α MAPK, which also blocked KOR-induced tyrosine phosphorylation of the inwardly rectifying potassium channel (GIRK) subunit Kir3.1 in VTA dopaminergic neurons. Consistent with the reduced response, GIRK phosphorylation at this amino terminal tyrosine residue (Y12) enhances channel deactivation. Thus, contrary to prevailing expectations, these results suggest that κ opioid-induced aversion requires regulation of VTA dopaminergic neuron somatic excitability through a p38α MAPK effect on GIRK deactivation kinetics rather than by presynaptically inhibiting dopamine release. SIGNIFICANCE STATEMENT Kappa opioid receptor (KOR) agonists have the potential to be effective, nonaddictive analgesics, but their therapeutic utility is greatly limited by adverse effects on mood. Understanding how KOR activation produces dysphoria is key to the development of better analgesics and to defining how the endogenous dynorphin opioids produce their depression-like effects. Results in this study show that the aversive effects of κ receptor activation required arrestin-dependent p38α MAPK activation in dopamine neurons but did not require inhibition of dopamine release in the nucleus accumbens. Thus, contrary to the prevailing view, inhibition of mesolimbic dopamine release does not mediate the aversive effects of KOR activation and functionally selective κ opioids that do not activate arrestin signaling may be effective analgesics lacking dysphoric effects. PMID:26377476

  12. Stimulants as Specific Inducers of Dopamine-Independent σ Agonist Self-Administration in Rats

    PubMed Central

    Hiranita, Takato; Soto, Paul L.; Tanda, Gianluigi; Kopajtic, Theresa A.

    2013-01-01

    A previous study showed that cocaine self-administration induced dopamine-independent reinforcing effects of σ agonists mediated by their selective actions at σ1 receptors (σ1Rs), which are intracellularly mobile chaperone proteins implicated in abuse-related effects of stimulants. The present study assessed whether the induction was specific to self-administration of cocaine. Rats were trained to self-administer the dopamine releaser, d-methamphetamine (0.01–0.32 mg/kg per injection), the μ-opioid receptor agonist, heroin (0.001–0.032 mg/kg per injection), and the noncompetitive N-methyl-d-aspartate receptor/channel antagonist ketamine (0.032–1.0 mg/kg per injection). As with cocaine, self-administration of d-methamphetamine induced reinforcing effects of the selective σ1R agonists PRE-084 [2-(4-morpholinethyl)1-phenylcyclohexanecarboxylate hydrochloride] and (+)-pentazocine (0.032–1.0 mg/kg per injection, each). In contrast, neither self-administration of heroin nor ketamine induced PRE-084 or (+)-pentazocine (0.032–10 mg/kg per injection, each) self-administration. Although the σ1R agonists did not maintain responding in subjects with histories of heroin or ketamine self-administration, substitution for those drugs was obtained with appropriate agonists (e.g., remifentanil, 0.1–3.2 µg/kg per injection, for heroin and (5S,10R)-(+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine ((+)-MK 801; dizocilpine), 0.32–10.0 µg/kg per injection, for ketamine). The σR antagonist N-[2-(3,4-dichlorophenyl)ethyl]-N-methyl-2-(1-pyrrolidinyl)ethylamine dihydrobromide (BD 1008; 1.0–10 mg/kg) dose-dependently blocked PRE-084 self-administration but was inactive against d-methamphetamine, heroin, and ketamine. In contrast, PRE-084 self-administration was affected neither by the dopamine receptor antagonist (+)-butaclamol (10–100 μg/kg) nor by the opioid antagonist (−)-naltrexone (1.0–10 mg/kg), whereas these antagonists were active against d-methamphetamine and heroin self-administration, respectively. The results indicate that experience specifically with indirect-acting dopamine agonists induces reinforcing effects of previously inactive σ1R agonists. It is further suggested that induced σ1R reinforcing mechanisms may play an essential role in treatment-resistant stimulant abuse, suggesting new approaches for the development of effective medications for its treatment. PMID:23908387

  13. Measuring Cohesion between Macromolecular Filaments One Pair at a Time: Depletion-Induced Microtubule Bundling

    NASA Astrophysics Data System (ADS)

    Hilitski, Feodor; Ward, Andrew R.; Cajamarca, Luis; Hagan, Michael F.; Grason, Gregory M.; Dogic, Zvonimir

    2015-04-01

    In the presence of nonadsorbing polymers, colloidal particles experience ubiquitous attractive interactions induced by depletion forces. Here, we measure the depletion interaction between a pair of microtubule filaments using a method that combines single filament imaging with optical trapping. By quantifying the dependence of filament cohesion on both polymer concentration and solution ionic strength, we demonstrate that the minimal model of depletion, based on the Asakura-Oosawa theory, fails to quantitatively describe the experimental data. By measuring the cohesion strength in two- and three- filament bundles, we verify pairwise additivity of depletion interactions for the specific experimental conditions. The described experimental technique can be used to measure pairwise interactions between various biological or synthetic filaments and complements information extracted from bulk osmotic stress experiments.

  14. Involvement of dopamine receptors and beta-arrestin in metamphetamine-induced inclusions formation in PC12 cells.

    PubMed

    Fornai, Francesco; Lenzi, Paola; Capobianco, Loredana; Iacovelli, Luisa; Scarselli, Pamela; Lazzeri, Gloria; De Blasi, Antonio

    2008-06-01

    Exposure of PC12 cells to metamphetamine (MA) induces the formation of multilamellar structures (whorls) resembling autophagic granules that subsequently develop as intracellular inclusions. These inclusions stain for a variety of antigens belonging to the ubiquitin proteasome pathway. Since MA-induced intracellular bodies require the presence of dopamine in the present study we analyzed the role of dopamine (DA) receptors in producing neuronal inclusions. Moreover, we investigated potential signaling pathways which could lead to ubiquitination in the presence of MA. Based on recent reports that ubiquitination of beta-adrenergic receptors is promoted by beta-arrestin which shuttles proteins from the plasma membrane to the ubiquitin proteasome system we investigated whether beta-arrestin is involved in MA-induced inclusion formation. Our experiments document that (i) beta-arrestin was associated with MA-induced intracellular bodies; (ii) MA induced a rapid and reversible ubiquitination of beta-arrestin; (iii) dopamine antagonists reduced both MA-induced beta-arrestin ubiquitination and intracellular whorls formation; (iv) the number of MA-induced intracellular bodies was reduced in cells transfected with the beta-arrestin dominant negative mutant, betaarrV53D and was increased by the persistently ubiquitinated beta-arrestin-ubiquitin fusion protein. In conclusion, the present study demonstrates the involvement of beta-arrestin in MA-induced intracellular bodies and the participation of dopamine receptors in this process. PMID:18266935

  15. Role of the basolateral amygdala dopamine receptors in arachidonylcyclopropylamide-induced fear learning deficits.

    PubMed

    Nasehi, Mohammad; Hajian, Maryam; Ebrahimi-Ghiri, Mohaddeseh; Zarrindast, Mohammad-Reza

    2016-01-01

    There is much evidence suggesting that the mesoamygdala dopaminergic (DAergic) system plays a crucial role in the formation and expression of fear conditioning, with both D1 and D2 receptors being involved. In addition, cannabinoid CB1 receptor (CB1R) signaling modulates DAergic pathways. The present study sought to determine the involvement of basolateral amygdala (BLA) dopamine receptors in arachidonylcyclopropylamide (ACPA)-induced fear learning deficits. Context- and tone-dependent fear conditioning in adult male NMRI mice was evaluated. Pre-training intraperitoneal administration of ACPA (0.1mg/kg) decreased the percentage of freezing in context- or tone-dependent fear conditioning, suggesting an acquisition impairment. Pre-training intra-BLA microinjection of a subthreshold dose of SKF38393 (D1-like receptor agonist), SCH23390 (D1-like receptor antagonist), quinpirole (D2-like receptor agonist), or sulpiride (D2-like receptor antagonist) did not alter the context-dependent fear learning deficit induced by ACPA, while SKF38393 or quinpirole restored ACPA effect on tone-dependent fear learning. Moreover, SKF38393 (1?g/mouse), SCH23390 (0.04 and 0.08?g/mouse), or quinpirole (0.1?g/mouse) all impaired context-dependent fear learning. It is concluded that D1 or D2 dopamine (DA) receptor activation restores tone- but not context-dependent fear learning deficit induced by CB1 activation using ACPA. PMID:26546370

  16. Depletion of white adipocyte progenitors induces beige adipocyte differentiation and suppresses obesity development

    PubMed Central

    Daquinag, A C; Tseng, C; Salameh, A; Zhang, Y; Amaya-Manzanares, F; Dadbin, A; Florez, F; Xu, Y; Tong, Q; Kolonin, M G

    2015-01-01

    Overgrowth of white adipose tissue (WAT) in obesity occurs as a result of adipocyte hypertrophy and hyperplasia. Expansion and renewal of adipocytes relies on proliferation and differentiation of white adipocyte progenitors (WAP); however, the requirement of WAP for obesity development has not been proven. Here, we investigate whether depletion of WAP can be used to prevent WAT expansion. We test this approach by using a hunter-killer peptide designed to induce apoptosis selectively in WAP. We show that targeted WAP cytoablation results in a long-term WAT growth suppression despite increased caloric intake in a mouse diet-induced obesity model. Our data indicate that WAP depletion results in a compensatory population of adipose tissue with beige adipocytes. Consistent with reported thermogenic capacity of beige adipose tissue, WAP-depleted mice display increased energy expenditure. We conclude that targeting of white adipocyte progenitors could be developed as a strategy to sustained modulation of WAT metabolic activity. PMID:25342467

  17. Herp depletion inhibits zearalenone-induced cell death in RAW 264.7 macrophages.

    PubMed

    Chen, Fenglei; Lin, Pengfei; Wang, Nan; Yang, Diqi; Wen, Xin; Zhou, Dong; Wang, Aihua; Jin, Yaping

    2016-04-01

    Herp is an endoplasmic reticulum (ER) membrane protein and strongly induced by the ER stress that not only participates in the unfolded protein response (UPR) under the ER stress, but also in cell autophagy under glucose starvation (GS). However, we do not know whether Herp plays any roles in other responses, such as zearalenone (ZEA). In this study, we constructed recombinant lentiviral vectors for Herp shRNA expression and generated stable Herp knockdown RAW 264.7 macrophages. Flow cytometry analysis showed Herp depletion could inhibit cell death induced by ZEA. Western blot analysis revealed that Herp depletion could up-regulate autophagy-related protein LC3-I conversion into LC3-II and the expression of ER stress-related protein CHOP. These results suggest that Herp depletion inhibits cell death by up-regulating autophagy. PMID:26723276

  18. Nestin depletion induces melanoma matrix metalloproteinases and invasion

    PubMed Central

    Lee, Chung-Wei; Zhan, Qian; Lezcano, Cecilia; Frank, Markus H.; Huang, John; Larson, Allison; Lin, Jennifer Y.; Wan, Marilyn T.; Lin, Ping-I; Ma, Jie; Kleffel, Sonja; Schatton, Tobias; Lian, Christine G.; Murphy, George F.

    2015-01-01

    Matrix metalloproteinases (MMPs) are key biological mediators of processes as diverse as wound healing, embryogenesis, and cancer progression. Although MMPs may be induced through multiple signaling pathways, the precise mechanisms for their regulation in cancer are incompletely understood. Because cytoskeletal changes are known to accompany MMP expression, we sought to examine the potential role of the poorly understood cytoskeletal protein, nestin, in modulating melanoma MMPs. Nestin knockdown (KD) upregulated expression of specific MMPs and MMP-dependent invasion both through extracellular matrix barriers in vitro and in peritumoral connective tissue of xenografts in vivo. Development of 3-dimensionsal melanospheres that in vitro partially recapitulate non-invasive tumorigenic melanoma growth was inhibited by nestin KD, although ECM invasion by aberrant melanospheres that did form was enhanced. Mechanistically, nestin KD-dependent melanoma invasion was associated with intracellular redistribution of phosphorylated focal adhesion kinase (pFAK) and increased melanoma cell responsiveness to transforming growth factor-beta (TGF-?), both implicated in pathways of melanoma invasion. The results suggest that the heretofore poorly understood intermediate filament, nestin, may serve as a novel mediator of MMPs critical to melanoma virulence. PMID:25365206

  19. Hyperthermia, polyamine depletion, and inhibition of X-ray-induced DNA strand break repair

    SciTech Connect

    Snyder, R.D.; Lachmann, P.J. )

    1989-10-01

    We have recently demonstrated that HeLa cells that had been depleted of polyamines by treatment with inhibitors of polyamine biosynthesis were deficient in their ability to repair X-ray-induced DNA strand breaks. Since it had previously been demonstrated that hyperthermic shock also inhibited strand break repair following X irradiation and that hyperthermia resulted in a leakage of polyamines from cells, it seemed of interest to examine whether the inhibition of repair by hyperthermia was related to this loss of cellular polyamines. In the present paper it is demonstrated that both polyamine depletion and hyperthermia inhibit strand closure, and that a combined treatment further reduces the rate of repair. In cells not depleted of polyamines, repair is restored to normal levels if hyperthermia treatment is followed by a 4-h incubation at 37 degrees C before X irradiation. In polyamine-depleted cells, this 37 degrees C incubation does not result in a return of repair ability. Polyamine supplementation was not effective in reversing hyperthermia-dependent repair inhibition, and, in fact, restoration of repair in control cells following hyperthermic shock corresponded to a time at which polyamines show a maximum decrease in those cells. These results suggest that the inhibition of repair and the increased radiosensitivity observed in hyperthermically treated cells is not related to polyamine depletion. However, data further suggest that polyamine-depleted cells may have other alterations, perhaps in chromatin, which render them more sensitive to thermal inhibition of repair.

  20. Activation of D1 dopamine receptors induces emergence from isoflurane general anesthesia

    PubMed Central

    Taylor, Norman E.; Chemali, Jessica J.; Brown, Emery N.; Solt, Ken

    2012-01-01

    BACKGROUND A recent study showed that methylphenidate induces emergence from isoflurane anesthesia. Methylphenidate inhibits dopamine and norepinephrine reuptake transporters. The objective of this study was to test the hypothesis that selective dopamine receptor activation induces emergence from isoflurane anesthesia. METHODS In adult rats, we tested the effects of chloro-APB (D1 agonist) and quinpirole (D2 agonist) on time to emergence from isoflurane general anesthesia. We then performed a dose–response study to test for chloro-APB-induced restoration of righting during continuous isoflurane anesthesia. SCH-23390 (D1 antagonist) was used to confirm that the effects induced by chloro-APB are specifically mediated by D1 receptors. In a separate group of animals, spectral analysis was performed on surface electroencephalogram recordings to assess neurophysiological changes induced by chloro-APB and quinpirole during isoflurane general anesthesia. RESULTS Chloro-APB decreased median time to emergence from 330s to 50s. The median difference in time to emergence between the saline control group (n=6) and the chloro-APB group (n = 6) was 222s (95% CI: 77–534s, Mann-Whitney test). This difference was statistically significant (p = 0.0082). During continuous isoflurane anesthesia, chloro-APB dose-dependently restored righting (n = 6) and decreased electroencephalogram delta power (n = 4). These effects were inhibited by pretreatment with SCH-23390. Quinpirole did not restore righting (n = 6) and had no significant effect on the electroencephalogram (n = 4) during continuous isoflurane anesthesia. CONCLUSIONS Activation of D1 receptors by chloro-APB decreases time to emergence from isoflurane anesthesia, and produces behavioral and neurophysiological evidence of arousal during continuous isoflurane anesthesia. These findings suggest that selective activation of a D1 receptor-mediated arousal mechanism is sufficient to induce emergence from isoflurane general anesthesia. PMID:23221866

  1. Further human evidence for striatal dopamine release induced by administration of Δ9-tetrahydrocannabinol (THC): selectivity to limbic striatum

    PubMed Central

    Bossong, Matthijs G.; Mehta, Mitul A.; van Berckel, Bart N.M.; Howes, Oliver D.; Kahn, René S.; Stokes, Paul R.A.

    2016-01-01

    Rationale Elevated dopamine function is thought to play a key role in both the rewarding effects of addictive drugs and the pathophysiology of schizophrenia. Accumulating epidemiological evidence indicates that cannabis use is a risk factor for the development of schizophrenia. However, human neurochemical imaging studies that examined the impact of Δ9-tetrahydrocannabinol (THC), the main psychoactive component in cannabis, on striatal dopamine release have provided inconsistent results. Objectives To assess the effect of a THC challenge on human striatal dopamine release in a large sample of healthy participants. Methods We combined human neurochemical imaging data from two previous studies that used [11C]raclopride positron emission tomography (PET) (n=7 and n=13, respectively) to examine the effect of THC on striatal dopamine neurotransmission in humans. PET images were re-analysed to overcome differences in PET data analysis. Results THC administration induced a significant reduction in [11C]raclopride binding in the limbic striatum (−3.65%, from 2.39±0.26 to 2.30±0.23, p=0.023). This is consistent with increased dopamine levels in this region. No significant differences between THC and placebo were found in other striatal subdivisions. Conclusions In the largest data set of healthy participants so far, we provide evidence for a modest increase in human striatal dopamine transmission after administration of THC compared to other drugs of abuse. This finding suggests limited involvement of the endocannabinoid system in regulating human striatal dopamine release, and thereby challenges the hypothesis that an increase in striatal dopamine levels after cannabis use is the primary biological mechanism underlying the associated higher risk of schizophrenia. PMID:25801289

  2. Depletion of Paraspeckle Protein 1 Enhances Methyl Methanesulfonate-Induced Apoptosis through Mitotic Catastrophe.

    PubMed

    Gao, Xiangjing; Zhang, Guanglin; Shan, Shigang; Shang, Yunlong; Chi, Linfeng; Li, Hongjuan; Cao, Yifei; Zhu, Xinqiang; Zhang, Meibian; Yang, Jun

    2016-01-01

    Previously, we have shown that paraspeckle protein 1 (PSPC1), a protein component of paraspeckles that was involved in cisplatin-induced DNA damage response (DDR), probably functions at the G1/S checkpoint. In the current study, we further examined the role of PSPC1 in another DNA-damaging agent, methyl methanesulfonate (MMS)-induced DDR, in particular, focusing on MMS-induced apoptosis in HeLa cells. First, it was found that MMS treatment induced the expression of PSPC1. While MMS treatment alone can induce apoptosis, depletion of PSPC1 expression using siRNA significantly increased the level of apoptosis following MMS exposure. In contrast, overexpressing PSPC1 decreased the number of apoptotic cells. Interestingly, morphological observation revealed that many of the MMS-treated PSPC1-knockdown cells contained two or more nuclei, indicating the occurrence of mitotic catastrophe. Cell cycle analysis further showed that depletion of PSPC1 caused more cells entering the G2/M phase, a prerequisite of mitosis catastrophe. On the other hand, over-expressing PSPC1 led to more cells accumulating in the G1/S phase. Taken together, these observations suggest an important role for PSPC1 in MMS-induced DDR, and in particular, depletion of PSPC1 can enhance MMS-induced apoptosis through mitotic catastrophe. PMID:26785254

  3. Depletion of Paraspeckle Protein 1 Enhances Methyl Methanesulfonate-Induced Apoptosis through Mitotic Catastrophe

    PubMed Central

    Gao, Xiangjing; Zhang, Guanglin; Shan, Shigang; Shang, Yunlong; Chi, Linfeng; Li, Hongjuan; Cao, Yifei; Zhu, Xinqiang; Zhang, Meibian; Yang, Jun

    2016-01-01

    Previously, we have shown that paraspeckle protein 1 (PSPC1), a protein component of paraspeckles that was involved in cisplatin-induced DNA damage response (DDR), probably functions at the G1/S checkpoint. In the current study, we further examined the role of PSPC1 in another DNA-damaging agent, methyl methanesulfonate (MMS)-induced DDR, in particular, focusing on MMS-induced apoptosis in HeLa cells. First, it was found that MMS treatment induced the expression of PSPC1. While MMS treatment alone can induce apoptosis, depletion of PSPC1 expression using siRNA significantly increased the level of apoptosis following MMS exposure. In contrast, overexpressing PSPC1 decreased the number of apoptotic cells. Interestingly, morphological observation revealed that many of the MMS-treated PSPC1-knockdown cells contained two or more nuclei, indicating the occurrence of mitotic catastrophe. Cell cycle analysis further showed that depletion of PSPC1 caused more cells entering the G2/M phase, a prerequisite of mitosis catastrophe. On the other hand, over-expressing PSPC1 led to more cells accumulating in the G1/S phase. Taken together, these observations suggest an important role for PSPC1 in MMS-induced DDR, and in particular, depletion of PSPC1 can enhance MMS-induced apoptosis through mitotic catastrophe. PMID:26785254

  4. EFFECTS OF SYSTEMIC NEUTROPHIL DEPLETION ON LPS-INDUCED AIRWAY DISEASE

    EPA Science Inventory

    Effects of Systemic Neutrophil Depletion on LPS-induced Airway Disease
    Jordan D. Savov, Stephen H. Gavett*, David M. Brass, Daniel L. Costa*, David A. Schwartz
    Pulmonary and Critical Care Division, Dept of Medicine ? Duke University Medical Center
    * National Health and E...

  5. Involvement of brain ANG II in acute sodium depletion induced salty taste changes.

    PubMed

    Lu, Bo; Yan, Jianqun; Yang, Xuejuan; Li, Jinrong; Chen, Ke

    2012-11-10

    Many investigations have been devoted to determining the role of angiotensin II (ANG II) and aldosterone (ALD) in sodium-depletion-induced sodium appetite, but few were focused on the mechanisms mediating the salty taste changes accompanied with sodium depletion. To further elucidate the mechanism of renin-angiotensin-aldosterone system (RAAS) action in mediating sodium intake behavior and accompanied salty taste changes, the present study examined the salty taste function changes accompanied with sodium depletion induced by furosemide (Furo) combined with different doses of angiotensin converting enzyme (ACE) inhibitor, captopril (Cap). Both the peripheral and central RAAS activity and the nuclei Fos immunoreactivity (Fos-ir) expression in the forebrain area were investigated. Results showed that sodium depletion induced by Furo+low-Cap increased taste preference for hypertonic NaCl solution with amplified brain action of ANG II but without peripheral action, while Furosemide combined with a high dose of captopril can partially inhibit the formation of brain ANG II, with parallel decreased effects on salty taste changes. And the resulting elevating forebrain ANG II may activate a variety of brain areas including SFO, PVN, SON and OVLT in sodium depleted rats injected with Furo+low-Cap, which underlines salty taste function and sodium intake behavioral changes. Neurons in SFO and OVLT may be activated mainly by brain ANG II, while PVN and SON activation may not be completely ANG II dependent. These findings suggested that forebrain derived ANG II may play a critical role in the salty taste function changes accompanied with acute sodium depletion. PMID:22846885

  6. Palmitate induces ER calcium depletion and apoptosis in mouse podocytes subsequent to mitochondrial oxidative stress

    PubMed Central

    Xu, S; Nam, S M; Kim, J-H; Das, R; Choi, S-K; Nguyen, T T; Quan, X; Choi, S J; Chung, C H; Lee, E Y; Lee, I-K; Wiederkehr, A; Wollheim, C B; Cha, S-K; Park, K-S

    2015-01-01

    Pathologic alterations in podocytes lead to failure of an essential component of the glomerular filtration barrier and proteinuria in chronic kidney diseases. Elevated levels of saturated free fatty acid (FFA) are harmful to various tissues, implemented in the progression of diabetes and its complications such as proteinuria in diabetic nephropathy. Here, we investigated the molecular mechanism of palmitate cytotoxicity in cultured mouse podocytes. Incubation with palmitate dose-dependently increased cytosolic and mitochondrial reactive oxygen species, depolarized the mitochondrial membrane potential, impaired ATP synthesis and elicited apoptotic cell death. Palmitate not only evoked mitochondrial fragmentation but also caused marked dilation of the endoplasmic reticulum (ER). Consistently, palmitate upregulated ER stress proteins, oligomerized stromal interaction molecule 1 (STIM1) in the subplasmalemmal ER membrane, abolished the cyclopiazonic acid-induced cytosolic Ca2+ increase due to depletion of luminal ER Ca2+. Palmitate-induced ER Ca2+ depletion and cytotoxicity were blocked by a selective inhibitor of the fatty-acid transporter FAT/CD36. Loss of the ER Ca2+ pool induced by palmitate was reverted by the phospholipase C (PLC) inhibitor edelfosine. Palmitate-dependent activation of PLC was further demonstrated by following cytosolic translocation of the pleckstrin homology domain of PLC in palmitate-treated podocytes. An inhibitor of diacylglycerol (DAG) kinase, which elevates cytosolic DAG, strongly promoted ER Ca2+ depletion by low-dose palmitate. GF109203X, a PKC inhibitor, partially prevented palmitate-induced ER Ca2+ loss. Remarkably, the mitochondrial antioxidant mitoTEMPO inhibited palmitate-induced PLC activation, ER Ca2+ depletion and cytotoxicity. Palmitate elicited cytoskeletal changes in podocytes and increased albumin permeability, which was also blocked by mitoTEMPO. These data suggest that oxidative stress caused by saturated FFA leads to mitochondrial dysfunction and ER Ca2+ depletion through FAT/CD36 and PLC signaling, possibly contributing to podocyte injury. PMID:26583319

  7. Palmitate induces ER calcium depletion and apoptosis in mouse podocytes subsequent to mitochondrial oxidative stress.

    PubMed

    Xu, S; Nam, S M; Kim, J-H; Das, R; Choi, S-K; Nguyen, T T; Quan, X; Choi, S J; Chung, C H; Lee, E Y; Lee, I-K; Wiederkehr, A; Wollheim, C B; Cha, S-K; Park, K-S

    2015-01-01

    Pathologic alterations in podocytes lead to failure of an essential component of the glomerular filtration barrier and proteinuria in chronic kidney diseases. Elevated levels of saturated free fatty acid (FFA) are harmful to various tissues, implemented in the progression of diabetes and its complications such as proteinuria in diabetic nephropathy. Here, we investigated the molecular mechanism of palmitate cytotoxicity in cultured mouse podocytes. Incubation with palmitate dose-dependently increased cytosolic and mitochondrial reactive oxygen species, depolarized the mitochondrial membrane potential, impaired ATP synthesis and elicited apoptotic cell death. Palmitate not only evoked mitochondrial fragmentation but also caused marked dilation of the endoplasmic reticulum (ER). Consistently, palmitate upregulated ER stress proteins, oligomerized stromal interaction molecule 1 (STIM1) in the subplasmalemmal ER membrane, abolished the cyclopiazonic acid-induced cytosolic Ca(2+) increase due to depletion of luminal ER Ca(2+). Palmitate-induced ER Ca(2+) depletion and cytotoxicity were blocked by a selective inhibitor of the fatty-acid transporter FAT/CD36. Loss of the ER Ca(2+) pool induced by palmitate was reverted by the phospholipase C (PLC) inhibitor edelfosine. Palmitate-dependent activation of PLC was further demonstrated by following cytosolic translocation of the pleckstrin homology domain of PLC in palmitate-treated podocytes. An inhibitor of diacylglycerol (DAG) kinase, which elevates cytosolic DAG, strongly promoted ER Ca(2+) depletion by low-dose palmitate. GF109203X, a PKC inhibitor, partially prevented palmitate-induced ER Ca(2+) loss. Remarkably, the mitochondrial antioxidant mitoTEMPO inhibited palmitate-induced PLC activation, ER Ca(2+) depletion and cytotoxicity. Palmitate elicited cytoskeletal changes in podocytes and increased albumin permeability, which was also blocked by mitoTEMPO. These data suggest that oxidative stress caused by saturated FFA leads to mitochondrial dysfunction and ER Ca(2+) depletion through FAT/CD36 and PLC signaling, possibly contributing to podocyte injury. PMID:26583319

  8. Molindone: higher doses needed to block pergolide-induced elevation of serum corticosterone than to elevate dopamine metabolites in brain.

    PubMed

    Fuller, R W; Snoddy, H D

    1983-12-01

    Molindone at a dose of 3 mg/kg i.p. in rats prevented pergolide-induced decreases in brain DOPAC (3,4-dihydroxyphenylacetic acid) and HVA (homovanillic acid), causing instead significant increases in these dopamine metabolites when given in combination with pergolide. Molindone alone at 3 mg/kg caused two-fold or greater increases in DOPAC and HVA and at doses as low as 0.3 mg/kg caused significant increases in these metabolites. However, molindone at 3 mg/kg and lower doses was without effect on pergolide-induced elevation of serum corticosterone, though a higher dose of molindone, 10 mg/kg, significantly antagonized this increase in corticosterone. These data support earlier findings with molindone, suggesting it has greater affinity for presynaptic dopamine autoreceptors than for postsynaptic dopamine receptors. PMID:6645804

  9. Direct measurements of neutral density depletion by two-photon absorption laser-induced fluorescence spectroscopy

    SciTech Connect

    Aanesland, A.; Liard, L.; Leray, G.; Jolly, J.; Chabert, P.

    2007-09-17

    The ground state density of xenon atoms has been measured by spatially resolved laser-induced fluorescence spectroscopy with two-photon excitation in the diffusion chamber of a magnetized Helicon plasma. This technique allows the authors to directly measure the relative variations of the xenon atom density without any assumptions. A significant neutral gas density depletion was measured in the core of the magnetized plasma, in agreement with previous theoretical and experimental works. It was also found that the neutral gas density was depleted near the radial walls.

  10. Southwestern Tropical Atlantic coral growth response to atmospheric circulation changes induced by ozone depletion in Antarctica

    NASA Astrophysics Data System (ADS)

    Evangelista, H.; Wainer, I.; Sifeddine, A.; Corrège, T.; Cordeiro, R. C.; Lamounier, S.; Godiva, D.; Shen, C.-C.; Le Cornec, F.; Turcq, B.; Lazareth, C. E.; Hu, C.-Y.

    2015-08-01

    Climate changes induced by stratospheric ozone depletion over Antarctica have been recognized as an important consequence of the recently observed Southern Hemisphere atmospheric circulation. Here we present evidences that the Brazilian coast (Southwestern Atlantic) may have been impacted from both winds and sea surface temperature changes derived from this process. Skeleton analysis of massive coral species living in shallow waters off Brazil are very sensitive to air-sea interactions, and seem to record this impact. Growth rates of Brazilian corals show a trend reversal that fits the ozone depletion evolution, confirming that ozone impacts are far reaching and potentially affect coastal ecosystems in tropical environments.

  11. Canine distemper virus-induced depletion of uninfected lymphocytes is associated with apoptosis.

    PubMed

    Schobesberger, Martina; Summerfield, Artur; Doherr, Marcus G; Zurbriggen, Andreas; Griot, Christian

    2005-03-10

    Canine distemper virus (CDV), a negative stranded RNA morbillivirus, causes a multisystemic disease in dogs, which is associated with a severe immune suppression. The aim of the study was to examine the influence of early CDV infection on leukocyte depletion, lymphopenia and virus-induced cell death in dogs infected with a virulent CDV strain. From 10 infected dogs, peripheral blood leukocytes were harvested periodically, phenotyped and analyzed for CDV antigen content and apoptosis using Annexin V-FITC and propidium iodide labeling. CDV infection induced a severe CD3+ T cell and CD21+ B cell depletion in all animals at 3 days post-infection (d.p.i.). For dogs with severe distemper, developing virus persistence in the lymphoid tissue and central nervous system, this lymphopenia lasted until the end of the experiment. Increased levels of lymphocyte apoptosis were found at 3 d.p.i., and monocyte apoptosis at 6 d.p.i. This was more prominent in the group of animals with severe distemper. At 3 d.p.i. no leukocyte infection was detectable indicating that the early lymphocyte depletion and apoptosis was not a direct consequence of virus infection. Taken together, our results demonstrate that CDV-induced lymphopenia is an early event and that the degree of lymphocyte depletion correlates with the severity of disease and virus persistence in the lymphoid tissue and central nervous system. PMID:15661329

  12. The protective effect of dopamine against OGD/R injury-induced cell death in HT22 mouse hippocampal cells.

    PubMed

    Wang, Wenzhu; Zhao, Lixi; Bai, Fan; Zhang, Tong; Dong, Hao; Liu, Lixu

    2016-03-01

    Previous studies have shown that levo-dopamine (l-dopa) can improve the consciousness of certain patients with prolonged coma after cerebral ischemia-reperfusion injury, and promote cell growth in vivo. This study aimed to investigate whether l-dopa, which is used clinically to treat Parkinson's disease, might also ameliorate ischemia-reperfusion injury-induced cell death. The oxygen-glucose deprivation and re-oxygenation (OGD/R) model was used to mimic the ischemia-reperfusion pathological process in vitro. HT22 cells were treated with dopamine hydrochloride at different times (i.e., 2h prior to OGD, during the period of OGD, during the period of R, and throughout the period of OGD/R) and at different concentrations (i.e., 25?M, 50?M, 100?M). Lactate dehydrogenase (LDH) release, flow cytometry-annexin V, and propidium iodide staining with light microscopy showed that dopamine hydrochloride (added during re-oxygenation) promoted cell proliferation and facilitated maintenance of normal cell morphology. However, when present during oxygen-glucose deprivation for 18h and present throughout OGD/R, dopamine hydrochloride increased cell damage as manifested by shrinkage, rounding up, and reduced viability. In conclusion, dopamine protected HT22 cells from OGD/R injury-induced cell death only at a particular point in time, suggesting that it may be useful for treating severe ischemia-reperfusion brain injury. PMID:26867202

  13. Is there a role for nitric oxide in methamphetamine-induced dopamine terminal degeneration?

    PubMed

    Friend, Danielle M; Fricks-Gleason, Ashley N; Keefe, Kristen A

    2014-02-01

    Methamphetamine (METH) abuse results in long-term damage to the dopaminergic system, manifesting as decreases in dopamine (DA) tissue content, DA transporter binding, as well as tyrosine hydroxylase and vesicular monoamine transporter immunostaining. However, the exact cascade of events that ultimately result in this damage has not been clearly elucidated. One factor that has been heavily implicated in METH-induced DA terminal degeneration is the production of nitric oxide (NO). Unfortunately, many of the studies attempting to clarify the role of NO in METH-induced neurotoxicity have been confounded by issues such as the disruption of METH-induced hyperthermia, preventing the formation of strong conclusions. As a result, there is a body of work suggesting that NO is sufficient for METH-induced neurotoxicity, while other studies suggest that NO does not play a role in METH-induced degeneration of DA nerve terminals. This review summarizes the existing studies investigating the role of NO in METH-induced neurotoxicity, and argues that while NO may be necessary for METH-induced neurotoxicity, it is not sufficient. Finally, important areas of future investigation are highlighted and discussed. PMID:23918001

  14. Neutrophil Depletion Attenuates Placental Ischemia-Induced Hypertension in the Rat

    PubMed Central

    Regal, Jean F.; Lillegard, Kathryn E.; Bauer, Ashley J.; Elmquist, Barbara J.; Loeks-Johnson, Alex C.; Gilbert, Jeffrey S.

    2015-01-01

    Preeclampsia is characterized by reduced placental perfusion with placental ischemia and hypertension during pregnancy. Preeclamptic women also exhibit a heightened inflammatory state and greater number of neutrophils in the vasculature compared to normal pregnancy. Since neutrophils are associated with tissue injury and inflammation, we hypothesized that neutrophils are critical to placental ischemia-induced hypertension and fetal demise. Using the reduced uteroplacental perfusion pressure (RUPP) model of placental ischemia-induced hypertension in the rat, we determined the effect of neutrophil depletion on blood pressure and fetal resorptions. Neutrophils were depleted with repeated injections of polyclonal rabbit anti-rat polymorphonuclear leukocyte (PMN) antibody (antiPMN). Rats received either antiPMN or normal rabbit serum (Control) on 13.5, 15.5, 17.5, and 18.5 days post conception (dpc). On 14.5 dpc, rats underwent either Sham surgery or clip placement on ovarian arteries and abdominal aorta to reduce uterine perfusion pressure (RUPP). On 18.5 dpc, carotid arterial catheters were placed and mean arterial pressure (MAP) was measured on 19.5 dpc. Neutrophil-depleted rats had reduced circulating neutrophils from 14.5 to 19.5 dpc compared to Control, as well as decreased neutrophils in lung and placenta on 19.5 dpc. MAP increased in RUPP Control vs Sham Control rats, and neutrophil depletion attenuated this increase in MAP in RUPP rats without any effect on Sham rats. The RUPP-induced increase in fetal resorptions and complement activation product C3a were not affected by neutrophil depletion. Thus, these data are the first to indicate that neutrophils play an important role in RUPP hypertension and that cells of the innate immune system may significantly contribute to pregnancy-induced hypertension. PMID:26135305

  15. Involvement of iron depletion in palmitate-induced lipotoxicity of beta cells.

    PubMed

    Jung, Ik-Rak; Choi, Sung-E; Jung, Jong-Gab; Lee, Sang-A; Han, Seung Jin; Kim, Hae Jin; Kim, Dae Jung; Lee, Kwan-Woo; Kang, Yup

    2015-05-15

    High levels of plasma free fatty acid are thought to contribute to the loss of pancreatic beta-cells in type 2 diabetes. In particular, saturated fatty acid such as palmitate or stearate can induce apoptosis in cultured beta cells (lipotoxicity). Endoplasmic reticulum stress is a critical mediator of free fatty acid-induced lipotoxicity. Recently, disorders in mitochondrial respiratory metabolism have been linked to lipotoxicity. Since iron is a critical component of respiratory metabolism, this study is initiated to determine whether abnormal iron metabolism is involved in palmitate-induced beta cell death. Immunoblotting analysis showed that treatment of INS-1 beta cells with palmitate reduced the level of transferrin receptor 1 (TfR1), but increased the level of heavy chain ferritin (FTH). In addition, palmitate reduced intracellular labile iron pool. Whereas iron depletion through treatment with iron-chelators deferoxamine or deferasirox augmented palmitate-induced cell death, iron supplementation with ferric chloride, ferrous sulfate, or holo-transferrin significantly protected cells against palmitate-induced death. Furthermore, overexpression of TfR1 reduced palmitate-induced cell death, whereas knockdown of TfR1 augmented cell death. In particular, treatment with deferoxamine increased the level of endoplasmic reticulum (ER) stress markers phospho-PERK, phospho-eIF2?, CHOP and phospho-c-Jun N-terminal kinase. Treatment with chemical chaperone significantly protected cells against deferoxamine-induced apoptosis. Iron supplementation also protected cells against palmitate-induced primary islet death. These data suggest that iron depletion plays an important role in palmitate-induced beta cell death through inducing ER stress. Therefore, attempts to block iron depletion might be able to prevent beta cell loss in type 2 diabetes. PMID:25779532

  16. Dopamine-induced dissociation of BOLD and neural activity in macaque visual cortex.

    PubMed

    Zaldivar, Daniel; Rauch, Alexander; Whittingstall, Kevin; Logothetis, Nikos K; Goense, Jozien

    2014-12-01

    Neuromodulators determine how neural circuits process information during cognitive states such as wakefulness, attention, learning, and memory. fMRI can provide insight into their function and dynamics, but their exact effect on BOLD responses remains unclear, limiting our ability to interpret the effects of changes in behavioral state using fMRI. Here, we investigated the effects of dopamine (DA) injections on neural responses and haemodynamic signals in macaque primary visual cortex (V1) using fMRI (7T) and intracortical electrophysiology. Aside from DA's involvement in diseases such as Parkinson's and schizophrenia, it also plays a role in visual perception. We mimicked DAergic neuromodulation by systemic injection of L-DOPA and Carbidopa (LDC) or by local application of DA in V1 and found that systemic application of LDC increased the signal-to-noise ratio (SNR) and amplitude of the visually evoked neural responses in V1. However, visually induced BOLD responses decreased, whereas cerebral blood flow (CBF) responses increased. This dissociation of BOLD and CBF suggests that dopamine increases energy metabolism by a disproportionate amount relative to the CBF response, causing the reduced BOLD response. Local application of DA in V1 had no effect on neural activity, suggesting that the dopaminergic effects are mediated by long-range interactions. The combination of BOLD-based and CBF-based fMRI can provide a signature of dopaminergic neuromodulation, indicating that the application of multimodal methods can improve our ability to distinguish sensory processing from neuromodulatory effects. PMID:25456449

  17. Dopamine Induces LTP Differentially in Apical and Basal Dendrites through BDNF and Voltage-Dependent Calcium Channels

    ERIC Educational Resources Information Center

    Navakkode, Sheeja; Sajikumar, Sreedharan; Korte, Martin; Soong, Tuck Wah

    2012-01-01

    The dopaminergic modulation of long-term potentiation (LTP) has been studied well, but the mechanism by which dopamine induces LTP (DA-LTP) in CA1 pyramidal neurons is unknown. Here, we report that DA-LTP in basal dendrites is dependent while in apical dendrites it is independent of activation of L-type voltage-gated calcium channels (VDCC).…

  18. AMPHETAMINE-, SCOPOLAMINE-, AND CAFFEINE-INDUCED LOCOMOTOR ACTIVITY FOLLOWING 6-HYDROXYDOPAMINE LESIONS OF THE MESOLIMBIC DOPAMINE SYSTEM

    EPA Science Inventory

    As previously reported, 6-hydroxydopamine (6-OHDA) lesions to the region of the nucleus accumbens blocked the locomotor activation induced by low doses of d-amphetamine, and produced a supersensitive locomotor response to the dopamine (DA) agonist, apomorphine. This same lesion, ...

  19. Dopamine Induces LTP Differentially in Apical and Basal Dendrites through BDNF and Voltage-Dependent Calcium Channels

    ERIC Educational Resources Information Center

    Navakkode, Sheeja; Sajikumar, Sreedharan; Korte, Martin; Soong, Tuck Wah

    2012-01-01

    The dopaminergic modulation of long-term potentiation (LTP) has been studied well, but the mechanism by which dopamine induces LTP (DA-LTP) in CA1 pyramidal neurons is unknown. Here, we report that DA-LTP in basal dendrites is dependent while in apical dendrites it is independent of activation of L-type voltage-gated calcium channels (VDCC).

  20. Plasmacytoid dendritic cells promote HIV-1induced group 3 innate lymphoid cell depletion

    PubMed Central

    Zhang, Zheng; Cheng, Liang; Zhao, Juanjuan; Li, Guangming; Zhang, Liguo; Chen, Weiwei; Nie, Weiming; Reszka-Blanco, Natalia J.; Wang, Fu-Sheng; Su, Lishan

    2015-01-01

    Group 3 innate lymphoid cells (ILC3s) have demonstrated roles in promoting antibacterial immunity, maintaining epithelial barrier function, and supporting tissue repair. ILC3 alterations are associated with chronic inflammation and inflammatory disease; however, the characteristics and relevant regulatory mechanisms of this cell population in HIV-1 infection are poorly understood due in part to a lack of a robust model. Here, we determined that functional human ILC3s develop in lymphoid organs of humanized mice and that persistent HIV-1 infection in this model depletes ILC3s, as observed in chronic HIV-1infected patients. In HIV-1infected mice, effective antiretroviral therapy reversed the loss of ILC3s. HIV-1dependent reduction of ILC3s required plasmacytoid dendritic cells (pDCs), IFN-I, and the CD95/FasL pathway, as targeted depletion or blockade of these prevented HIV-1induced ILC3 depletion in vivo and in vitro, respectively. Finally, we determined that HIV-1 infection induces CD95 expression on ILC3s via a pDC- and IFN-Idependent mechanism that sensitizes ILC3s to undergo CD95/FasL-mediated apoptosis. We conclude that chronic HIV-1 infection depletes ILC3s through pDC activation, induction of IFN-I, and CD95-mediated apoptosis. PMID:26301812

  1. MODULATION OF THE BCL-2 FAMILY BLOCKS SEPSIS-INDUCED DEPLETION OF DENDRITIC CELLS AND MACROPHAGES

    PubMed Central

    Peck-Palmer, Octavia M.; Unsinger, Jacqueline; Chang, Katherine C.; McDonough, Jacquelyn S.; Perlman, Harris; McDunn, Jonathan E.; Hotchkiss, Richard S.

    2009-01-01

    This study examined the fate of dendritic cells (DCs) and macrophages (MΦ) in vivo in a murine model of sepsis. Wild-type, knockout, and transgenic mice were used to examine the role of Bcl-2 family members on the regulation of splenic DCs and MΦ survival. Bim knockout (Bim−/−) mice and mice overexpressing Bcl-2 in selected hematopoietic cells were used: (a) overexpression of Bcl-2 in all hematopoietic cells using a vav promoter (Vav–Bcl-2) and (b) overexpression of Bcl-2 in all MHC class I cells (H-2K–Bcl-2). Mice underwent sham surgery or cecal ligation and puncture, and absolute numbers of splenic DCs and MΦ were determined. Importantly, two distinct MΦ populations, that is, well-differentiated “mature” MΦ population and a less differentiated “immature,” “monocyte-like” (IMΦ) population were identified that demonstrated differential susceptibility to apoptosis. In wild-type mice, sepsis induced a 64% ± 7% and a 77% ± 3% decrease in absolute cell numbers of splenic DCs and IMΦ, respectively (n = 7, P < 0.05). Mature MΦ were not depleted in sepsis. No significant cell depletion was evident in Vav–Bcl-2, H-2K–Bcl-2, or Bim−/− mice. We conclude that sepsis induces a major depletion of developing MΦ as well as DCs, and this depletion may be an important mechanism of immune suppression in sepsis. PMID:18838943

  2. Dopamine improves exploration after expectancy violations and induces psychotic-like experiences in patients with Parkinson's disease.

    PubMed

    Polner, Bertalan; Moustafa, Ahmed A; Nagy, Helga; Takáts, Annamária; Győrfi, Orsolya; Kéri, Szabolcs

    2016-03-11

    Dopamine neurons are sensitive to novel and rewarding events, and dopamine signals can modulate learning in higher-level brain networks. Additionally, dopamine abnormalities appear to be central to the pathophysiology of schizophrenia spectrum disorders. In this study, we investigate the dopaminergic modulation of schizotypal traits and exploration after expectancy violations in Parkinson's disease (PD) patients on dopamine replacement therapy. Exploration after expectancy violations was measured with a latent inhibition and an anomaly categorisation task. Patients with PD had significantly elevated levels of schizotypy and reduced latent inhibition, relative to the controls. Anomaly categorisation was enhanced at trend level among the patients. Dopaminergic antiparkinsonian drugs showed dose-dependent effects: they induced psychotic-like experiences, and at the same time, they disrupted latent inhibition and made categorisation of anomaly more efficient. Most of these findings were replicated in an independent sample of patients with PD. An up-regulated dopamine system in medicated PD patients might tune higher-level brain networks to engage in learning when faced with unexpected information, and therefore hasten the updating of internal models. PMID:26820375

  3. Depletion-induced forces and crowding in polymer-nanoparticle mixtures: Role of polymer shape fluctuations and penetrability

    NASA Astrophysics Data System (ADS)

    Lim, Wei Kang; Denton, Alan R.

    2016-01-01

    Depletion forces and macromolecular crowding govern the structure and function of biopolymers in biological cells and the properties of polymer nanocomposite materials. To isolate and analyze the influence of polymer shape fluctuations and penetrability on depletion-induced interactions and crowding by nanoparticles, we model polymers as effective penetrable ellipsoids, whose shapes fluctuate according to the probability distributions of the eigenvalues of the gyration tensor of an ideal random walk. Within this model, we apply Monte Carlo simulation methods to compute the depletion-induced potential of mean force between hard nanospheres and crowding-induced shape distributions of polymers in the protein limit, in which polymer coils can be easily penetrated by smaller nanospheres. By comparing depletion potentials from simulations of ellipsoidal and spherical polymer models with predictions of polymer field theory and free-volume theory, we show that polymer depletion-induced interactions and crowding depend sensitively on polymer shapes and penetrability, with important implications for bulk thermodynamic phase behavior.

  4. No evidence for attenuated stress-induced extrastriatal dopamine signaling in psychotic disorder

    PubMed Central

    Hernaus, D; Collip, D; Kasanova, Z; Winz, O; Heinzel, A; van Amelsvoort, T; Shali, S M; Booij, J; Rong, Y; Piel, M; Pruessner, J; Mottaghy, F M; Myin-Germeys, I

    2015-01-01

    Stress is an important risk factor in the etiology of psychotic disorder. Preclinical work has shown that stress primarily increases dopamine (DA) transmission in the frontal cortex. Given that DA-mediated hypofrontality is hypothesized to be a cardinal feature of psychotic disorder, stress-related extrastriatal DA release may be altered in psychotic disorder. Here we quantified for the first time stress-induced extrastriatal DA release and the spatial extent of extrastriatal DA release in individuals with non-affective psychotic disorder (NAPD). Twelve healthy volunteers (HV) and 12 matched drug-free NAPD patients underwent a single infusion [18F]fallypride positron emission tomography scan during which they completed the control and stress condition of the Montreal Imaging Stress Task. HV and NAPD did not differ in stress-induced [18F]fallypride displacement and the spatial extent of stress-induced [18F]fallypride displacement in medial prefrontal cortex (mPFC) and temporal cortex (TC). In the whole sample, the spatial extent of stress-induced radioligand displacement in right ventro-mPFC, but not dorso-mPFC or TC, was positively associated with task-induced subjective stress. Psychotic symptoms during the scan or negative, positive and general subscales of the Positive and Negative Syndrome Scale were not associated with stress-induced [18F]fallypride displacement nor the spatial extent of stress-induced [18F]fallypride displacement in NAPD. Our results do not offer evidence for altered stress-induced extrastriatal DA signaling in NAPD, nor altered functional relevance. The implications of these findings for the role of the DA system in NAPD and stress processing are discussed. PMID:25871972

  5. Dopamine is not essential for the development of methamphetamine-induced neurotoxicity

    PubMed Central

    Yuan, Jie; Darvas, Martin; Sotak, Bethany; Hatzidimitriou, George; McCann, Una D; Palmiter, Richard D; Ricaurte, George A

    2010-01-01

    It is widely believed that dopamine (DA) mediates methamphetamine (METH)-induced toxicity to brain dopaminergic neurons, because drugs that interfere with DA neurotransmission decrease toxicity, whereas drugs that increase DA neurotransmission enhance toxicity. However, temperature effects of drugs that have been used to manipulate brain DA neurotransmission confound interpretation of the data. Here we show that the recently reported ability of l-dihydroxyphenylalanine to reverse the protective effect of alpha-methyl-para-tyrosine on METH-induced DA neurotoxicity is also confounded by drug effects on body temperature. Further, we show that mice genetically engineered to be deficient in brain DA develop METH neurotoxicity, as long as the thermic effects of METH are preserved. In addition, we demonstrate that mice genetically engineered to have unilateral brain DA deficits develop METH-induced dopaminergic deficits that are of comparable magnitude on both sides of the brain. Taken together, these findings demonstrate that DA is not essential for the development of METH-induced dopaminergic neurotoxicity and suggest that mechanisms independent of DA warrant more intense investigation. PMID:20533999

  6. The Role of Dopamine in Reinforcement: Changes in Reinforcement Sensitivity Induced by D[subscript 1]-Type, D[subscript 2]-Type, and Nonselective Dopamine Receptor Agonists

    ERIC Educational Resources Information Center

    Bratcher, Natalie A.; Farmer-Dougan, Valeri; Dougan, James D.; Heidenreich, Byron A.; Garris, Paul A.

    2005-01-01

    Dose-dependent changes in sensitivity to reinforcement were found when rats were treated with low, moderate, and high doses of the partial dopamine D[subscript 1]-type receptor agonist SKF38393 and with the nonselective dopamine agonist apomorphine, but did not change when rats were treated with similar doses of the selective dopamine D[subscript

  7. The dopamine D1 receptor antagonist SCH 23390 can exert D1 agonist-like effects on rat nucleus accumbens neurons.

    PubMed

    Wachtel, S R; White, F J

    1995-10-13

    Interactions between the selective dopamine D1-class receptor antagonist SCH 23390 and the dopamine D2-class receptor agonist quinpirole on nucleus accumbens neurons were investigated with extracellular single cell recording and microiontophoresis. Because dopamine D1 receptor stimulation enables many dopamine D2 receptor-mediated effects, SCH 23390 was expected to antagonize quinpirole-induced inhibition of activity. Although concurrent iontophoretic administration of SCH 23390 attenuated the inhibitory effects of quinpirole on most neurons, the antagonist further suppressed the firing of most neurons during attempts to reverse quinpirole-induced inhibition. SCH 23390 also reinstated (enabled) quinpirole-induced inhibition in rats acutely depleted of dopamine. These findings suggest that under certain conditions, SCH 23390 may exert dopamine D1 agonist-like effects. PMID:8584215

  8. Nonlocal Entropic Repulsion Effects on Rod Polymer Induced Depletion Attraction between Spherical Particles

    NASA Astrophysics Data System (ADS)

    Chen, Yeng-Long; Schweizer, Kenneth

    2002-03-01

    The polymer liquid state integral equation approach for treating depletion phenomena in rigid rod-colloid suspensions is generalized to account for spatially nonlocal entropic repulsions which modify rod orientation near an impenetrable particle. A thermodynamically consistent theory for the rod segment-particle direct correlation function is formulated under athermal conditions for thin rods and all ratios of the rod length, L, to sphere diameter, D. Results for the polymer density profile near a colloid, the cross second virial coefficient, and the sphere-sphere depletion potential under dilute polymer conditions have been obtained. Relative to simpler approaches based on the (local) Percus-Yevick closure approximation, the new theory represents a qualitative improvement for the shape of the polymer density profile at small separations, and a major quantitative improvement for the depletion attraction strength at colloidal contact when D>L. Detailed comparisons reveal very good agreement of the theory with both exact simulation results for all size asymmetry ratios, and recent direct experimental measurements of the fd-virus(rod) induced depletion potential between silica colloids where L ~ D.

  9. The auxin-inducible degradation (AID) system enables versatile conditional protein depletion in C. elegans.

    PubMed

    Zhang, Liangyu; Ward, Jordan D; Cheng, Ze; Dernburg, Abby F

    2015-12-15

    Experimental manipulation of protein abundance in living cells or organisms is an essential strategy for investigation of biological regulatory mechanisms. Whereas powerful techniques for protein expression have been developed in Caenorhabditis elegans, existing tools for conditional disruption of protein function are far more limited. To address this, we have adapted the auxin-inducible degradation (AID) system discovered in plants to enable conditional protein depletion in C. elegans. We report that expression of a modified Arabidopsis TIR1 F-box protein mediates robust auxin-dependent depletion of degron-tagged targets. We document the effectiveness of this system for depletion of nuclear and cytoplasmic proteins in diverse somatic and germline tissues throughout development. Target proteins were depleted in as little as 20-30?min, and their expression could be re-established upon auxin removal. We have engineered strains expressing TIR1 under the control of various promoter and 3' UTR sequences to drive tissue-specific or temporally regulated expression. The degron tag can be efficiently introduced by CRISPR/Cas9-based genome editing. We have harnessed this system to explore the roles of dynamically expressed nuclear hormone receptors in molting, and to analyze meiosis-specific roles for proteins required for germ line proliferation. Together, our results demonstrate that the AID system provides a powerful new tool for spatiotemporal regulation and analysis of protein function in a metazoan model organism. PMID:26552885

  10. The auxin-inducible degradation (AID) system enables versatile conditional protein depletion in C. elegans

    PubMed Central

    Zhang, Liangyu; Ward, Jordan D.; Cheng, Ze; Dernburg, Abby F.

    2015-01-01

    Experimental manipulation of protein abundance in living cells or organisms is an essential strategy for investigation of biological regulatory mechanisms. Whereas powerful techniques for protein expression have been developed in Caenorhabditis elegans, existing tools for conditional disruption of protein function are far more limited. To address this, we have adapted the auxin-inducible degradation (AID) system discovered in plants to enable conditional protein depletion in C. elegans. We report that expression of a modified Arabidopsis TIR1 F-box protein mediates robust auxin-dependent depletion of degron-tagged targets. We document the effectiveness of this system for depletion of nuclear and cytoplasmic proteins in diverse somatic and germline tissues throughout development. Target proteins were depleted in as little as 20-30 min, and their expression could be re-established upon auxin removal. We have engineered strains expressing TIR1 under the control of various promoter and 3′ UTR sequences to drive tissue-specific or temporally regulated expression. The degron tag can be efficiently introduced by CRISPR/Cas9-based genome editing. We have harnessed this system to explore the roles of dynamically expressed nuclear hormone receptors in molting, and to analyze meiosis-specific roles for proteins required for germ line proliferation. Together, our results demonstrate that the AID system provides a powerful new tool for spatiotemporal regulation and analysis of protein function in a metazoan model organism. PMID:26552885

  11. Inhibition of titanium-particle-induced inflammatory osteolysis after local administration of dopamine and suppression of osteoclastogenesis via D2-like receptor signaling pathway.

    PubMed

    Yang, Huilin; Xu, Yaozeng; Zhu, Mo; Gu, Ye; Zhang, Wen; Shao, Hongguo; Wang, Yijun; Ping, Zichuan; Hu, Xuanyang; Wang, Liangliang; Geng, Dechun

    2016-02-01

    Chronic inflammation and extensive osteoclast formation play critical roles in wear-debris-induced peri-implant osteolysis. We investigated the potential impact of dopamine on titanium-particle-induced inflammatory osteolysis invivo and invitro. Twenty-eight C57BL/6J mice were randomly assigned to four groups: sham control (PBS treatment), titanium (titanium/PBS treatment), low- (titanium/2?gkg(-1)day(-1) dopamine) and high-dopamine (titanium/10?gkg(-1)day(-1) dopamine). After 2 weeks, mouse calvariae were collected for micro-computed tomography (micro-CT) and histomorphometry analysis. Bone-marrow-derived macrophages (BMMs) were isolated to assess osteoclast differentiation. Dopamine significantly reduced titanium-particle-induced osteolysis compared with the titanium group as confirmed by micro-CT and histomorphometric data. Osteoclast numbers were 34.9% and 59.7% (both p<0.01) lower in the low- and high-dopamine-treatment groups, respectively, than in the titanium group. Additionally, low RANKL, tumor necrosis factor-?, interleukin-1? and interleukin-6 immunochemistry staining were noted in dopamine-treatment groups. Dopamine markedly inhibited osteoclast formation, osteoclastogenesis-related gene expression and pro-inflammatory cytokine expression in BMMs in a dose-dependent manner. Moreover, the resorption area was decreased with 10(-9)M and 10(-8)M dopamine to 40.0% and 14.5% (both p<0.01), respectively. Furthermore, the inhibitory effect of dopamine was reversed by the D2-like-receptor antagonist haloperidol but not by the D1-like-receptor antagonist SCH23390. These results suggest that dopamine therapy could be developed into an effective and safe method for osteolysis-related disease caused by chronic inflammation and excessive osteoclast formation. PMID:26695376

  12. Footshock facilitates methamphetamine-induced conditioned suppression through HPA axis, not dopamine.

    PubMed

    Huang, Andrew Chih Wei; Wang, Shiun; Wu, Jos Jiun-Shian; Wang, Cheng Chung

    2015-03-15

    The present study examined whether footshock can enhance methamphetamine (MAMPH)-induced conditioned suppression and whether this effect involves the dopamine (DA) reward system or hypothalamic-pituitary-adrenal (HPA) axis. We also examined whether the footshock-induced enhancements of MAMPH-induced conditioned suppression are attributable to MAMPH's rewarding or aversive properties. During the footshock phase, all female rats received 0.1mg/kg haloperidol (HAL) and its vehicle (2% tartaric acid solution), or low and high doses of dexamethasone (DEX; 0.5 and 1.0mg/kg) and its vehicle before each footshock (1mA, 2s), or no footshock, in seven trials once per day. The control group did not receive any drugs or footshocks. All of the rats were then allowed 15min access to a 0.1% saccharin solution and then received 2mg/kg MAMPH in five trials once per day. Footshock exhibited an increase in MAMPH-induced taste suppression. The low- and high-dose DEX groups but not the HAL group exhibited a blocking effect of the footshock enhancements of MAMPH-induced taste suppression. The low- and high-dose DEX groups exhibited a significant decrease in corticosterone levels during the footshock treatment phase but not during the testing phase. Altogether, the HPA stress system and not the DA reward system, particularly D2 receptors, appear to mediate the footshock-induced enhancements of MAMPH-induced conditioned taste suppression, which may result from the aversive and not the rewarding properties of MAMPH. The present findings may provide some clinical implications for alternating aversively classical conditioning for psychiatric disorders. PMID:25592442

  13. Lateral Parabrachial Nucleus Serotonergic Mechanisms and Salt Appetite Induced by Sodium Depletion

    NASA Technical Reports Server (NTRS)

    Menani, Jose Vanderlei; DeLuca, Laurival Antonio, Jr.; Johnson, Alan Kim

    1998-01-01

    This study investigated the effects of bilateral injections of a serotonin (5-HT) receptor agonist into the lateral parabrachial nucleus on the intake of NaCl and water induced by 24-h water deprivation or by sodium depletion followed by 24 h of sodium deprivation (injection of the diuretic furosemide plus 24 h of d sodium-deficient diet). Rats had stainless steel cannulas implanted bilaterally into the LPBN. Bilateral LPBN injections of the serotonergic 5-HT(1/2) receptor antagonist methysergide (4 micro-g/200 nl at each site) increased hypertonic NaCl intake when tested 24 h after sodium depletion and after 24 h of water deprivation. Water intake also increased after bilateral injections of methysergide into the LPBN. In contrast, the intake of a palatable solution (0.06 M sucrose) under body fluid-replete conditions was not changed after bilateral LPBN methysergide injections. The results show that serotonergic mechanisms in the LPBN modulate water and sodium intake induced by volume depletion and sodium loss. The finding that sucrose intake was not affected by LPBN serotonergic blockade suggests that the effects of the methysergide treatment on the intakes of water and NaCl are not due to a mechanism producing a nonspecific enhancement of all ingestive behaviors.

  14. Serotonin depletion can enhance the cerebrovascular responses induced by cortical spreading depression via the nitric oxide pathway.

    PubMed

    Saengjaroentham, Chonlawan; Supornsilpchai, Weera; Ji-Au, Wilawan; Srikiatkhachorn, Anan; Maneesri-le Grand, Supang

    2015-02-01

    Serotonin (5-HT) is an important neurotransmitter involved in the control of neural and vascular responses. 5-HT depletion can induce several neurological disorders, including migraines. Studies on a cortical spreading depression (CSD) migraine animal model showed that the cortical neurons sensitivity, vascular responses, and nitric oxide (NO) production were significantly increased in 5-HT depletion. However, the involvement of NO in the cerebrovascular responses in 5-HT depletion remains unclear. This study aimed to investigate the role of NO in the CSD-induced alterations of cerebral microvessels in 5-HT depletion. Rats were divided into four groups: control, control with L-NAME treatment, 5-HT depleted, and 5-HT depleted with L-NAME treatment. 5-HT depletion was induced by intraperitoneal injection with para-chlorophenylalanine (PCPA) 3 days before the experiment. The CSD was triggered by KCl application. After the second wave of CSD, N-nitro-l-arginine methyl ester (L-NAME) or saline was intravenously injected into the rats with or without L-NAME treatment groups, respectively. The intercellular adhesion molecules-1 (ICAM-1), cell adhesion molecules-1 (VCAM-1), and the ultrastructural changes of the cerebral microvessels were examined. The results showed that 5-HT depletion significantly increased ICAM-1 and VCAM-1 expressions in the cerebral cortex. The number of endothelial pinocytic vesicles and microvilli was higher in the 5-HT depleted group when compared to the control. Interestingly, L-NAME treatment significantly reduced the abnormalities observed in the 5-HT depleted group. The results of this study demonstrated that an increase of NO production is one of the mechanisms involved in the CSD-induced alterations of the cerebrovascular responses in 5-HT depletion. PMID:24670256

  15. 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 (0.1-10mg/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 (12.5-100g/paw) in the ipsi, but not contralateral, paw. The peripheral action of aripiprazole (100g/paw) was reversed by haloperidol (0.1-10g/paw), suggesting the activation of dopamine receptors as a possible mechanism. Accordingly, quinpirole (25-100g/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 25g/paw). Finally, peripheral administration of NAN-190 (0.1-10?g/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. PMID:26325094

  16. Dopamine, reward learning, and active inference

    PubMed Central

    FitzGerald, Thomas H. B.; Dolan, Raymond J.; Friston, Karl

    2015-01-01

    Temporal difference learning models propose phasic dopamine signaling encodes reward prediction errors that drive learning. This is supported by studies where optogenetic stimulation of dopamine neurons can stand in lieu of actual reward. Nevertheless, a large body of data also shows that dopamine is not necessary for learning, and that dopamine depletion primarily affects task performance. We offer a resolution to this paradox based on an hypothesis that dopamine encodes the precision of beliefs about alternative actions, and thus controls the outcome-sensitivity of behavior. We extend an active inference scheme for solving Markov decision processes to include learning, and show that simulated dopamine dynamics strongly resemble those actually observed during instrumental conditioning. Furthermore, simulated dopamine depletion impairs performance but spares learning, while simulated excitation of dopamine neurons drives reward learning, through aberrant inference about outcome states. Our formal approach provides a novel and parsimonious reconciliation of apparently divergent experimental findings. PMID:26581305

  17. Polymer-Induced Depletion Interaction and Its Effect on Colloidal Sedimentation in Colloid-Polymer Mixtures

    NASA Technical Reports Server (NTRS)

    Tong, Penger

    1996-01-01

    In this paper we focus on the polymer-induced depletion attraction and its effect on colloidal sedimentation in colloid-polymer mixtures. We first report a small angle neutron scattering (SANS) study of the depletion effect in a mixture of hard-sphere-like colloid and non-adsorbing polymer. Then we present results of our recent sedimentation measurements in the same colloid-polymer mixture. A key parameter in controlling the sedimentation of heavy colloidal particles is the interparticle potential U(tau), which is the work required to bring two colloidal particles from infinity to a distance tau under a give solvent condition. This potential is known to affect the average settling velocity of the particles and experimentally one needs to have a way to continuously vary U(tau) in order to test the theory. The interaction potential U(tau) can be altered by adding polymer molecules into the colloidal suspension. In a mixture of colloid and non-adsorbing polymer, the potential U(tau) can develop an attractive well because of the depletion effect, in that the polymer chains are expelled from the region between two colloidal particles when their surface separation becomes smaller than the size of the polymer chains. The exclusion of polymer molecules from the space between the colloidal particles leads to an unbalanced osmotic pressure difference pushing the colloidal particles together, which results in an effective attraction between the two colloidal particles. The polymer-induced depletion attraction controls the phase stability of many colloid-polymer mixtures, which are directly of interest to industry.

  18. Thapsigargin-induced persistent intracellular calcium pool depletion and apoptosis in human hepatoma cells.

    PubMed

    Kaneko, Y; Tsukamoto, A

    1994-05-16

    We found that thapsigargin (Tg), a non-phorbol ester type tumor promoter that specifically inhibits endoplasmic reticulum Ca(2+)-ATPase, transiently increased the level of cytosolic free calcium ([Ca2+]i) and subsequently induced chromatin condensation, nuclear fragmentation, and internucleosomal DNA cleavage in cultured PLC/PRF/5 human hepatoma cells. These alterations were followed by the loss of plasma membrane integrity and by cell death. Epidermal growth factor (EGF) and vasopressin similarly elevated [Ca2+]i without causing DNA fragmentation which is characteristic of apoptosis. Consequently, the elevation of [Ca2+]i itself was not sufficient for causing Tg-induced cell death. On the other hand, preculturing the cells with Tg completely suppressed Ca2+ mobilization induced by EGF and vasopressin; a result that strongly suggests that Tg depleted the endoplasmic reticulum Ca2+ pool. Such depletion is hypothesized to induce apoptotic cell death in this hepatoma cell line by changing the nuclear Ca2+ levels which probably produce a structural change in chromatin. PMID:8019972

  19. Effects of tryptophan depletion on anxiety induced by simulated public speaking.

    PubMed

    Monteiro-dos-Santos, P C; Graeff, F G; dos-Santos, J E; Ribeiro, R P; Guimarães, F S; Zuardi, A W

    2000-05-01

    Several lines of evidence point to the participation of serotonin (5HT) in anxiety. Its specific role, however, remains obscure. The objective of the present study was to evaluate the effect of reducing 5HT-neurotransmission through an acute tryptophan depletion on anxiety induced by a simulated public speaking (SPS) test. Two groups of 14-15 subjects were submitted to a 24-h diet with a low or normal content of tryptophan and received an amino acid mixture without (TRY-) or with (TRY+) tryptophan under double-blind conditions. Five hours later they were submitted to the SPS test. The state-trait anxiety inventory (STAI) and the visual analogue mood scale (VAMS) were used to measure subjective anxiety. Both scales showed that SPS induced a significant increase in anxiety. Although no overall difference between groups was found, there was a trend (P = 0.078) to an interaction of group x gender x phases of the SPS, and a separate analysis of each gender showed an increase in anxiety measured by the STAI in females of the TRY- group. The results for the female TRY- group also suggested a greater arousing effect of the SPS test. In conclusion, the tryptophan depletion procedure employed in the present study did not induce a significant general change in subjective anxiety, but tended to induce anxiety in females. This suggests a greater sensitivity of the 5HT system to the effects of the procedure in this gender. PMID:10775890

  20. Nucleotide Pool Depletion Induces G-Quadruplex-Dependent Perturbation of Gene Expression

    PubMed Central

    Papadopoulou, Charikleia; Guilbaud, Guillaume; Schiavone, Davide; Sale, JulianE.

    2015-01-01

    Summary Nucleotide pool imbalance has been proposed to drive genetic instability in cancer. Here, we show that slowing replication forks by depleting nucleotide pools with hydroxyurea (HU) can also give rise to both transient and permanent epigenetic instability of a reporter locus, BU-1, in DT40 cells. HU induces stochastic formation of Bu-1low variants in dividing cells, which have lost the H3K4me3 present in untreated cells. This instability is potentiated by an intragenic G quadruplex, which also promotes local H2Ax phosphorylation and transient heterochromatinization. Genome-wide, gene expression changes induced by HU significantly overlap with those resulting from loss of the G4-helicases FANCJ, WRN, and BLM. Thus, the effects of global replication stress induced by nucleotide pool depletion can be focused by local replication impediments caused by G quadruplex formation to induce epigenetic instability and changes in gene expression, a mechanism that may contribute to selectable transcriptional changes in cancer. PMID:26686635

  1. Nucleotide Pool Depletion Induces G-Quadruplex-Dependent Perturbation of Gene Expression.

    PubMed

    Papadopoulou, Charikleia; Guilbaud, Guillaume; Schiavone, Davide; Sale, Julian E

    2015-12-22

    Nucleotide pool imbalance has been proposed to drive genetic instability in cancer. Here, we show that slowing replication forks by depleting nucleotide pools with hydroxyurea (HU) can also give rise to both transient and permanent epigenetic instability of a reporter locus, BU-1, in DT40 cells. HU induces stochastic formation of Bu-1(low) variants in dividing cells, which have lost the H3K4me3 present in untreated cells. This instability is potentiated by an intragenic G quadruplex, which also promotes local H2Ax phosphorylation and transient heterochromatinization. Genome-wide, gene expression changes induced by HU significantly overlap with those resulting from loss of the G4-helicases FANCJ, WRN, and BLM. Thus, the effects of global replication stress induced by nucleotide pool depletion can be focused by local replication impediments caused by G quadruplex formation to induce epigenetic instability and changes in gene expression, a mechanism that may contribute to selectable transcriptional changes in cancer. PMID:26686635

  2. Effect of sex chromosome complement on sodium appetite and Fos-immunoreactivity induced by sodium depletion.

    PubMed

    Dadam, Florencia M; Caeiro, Ximena E; Cisternas, Carla D; Macchione, Ana F; Cambiasso, María J; Vivas, Laura

    2014-02-01

    Previous studies indicate a sex chromosome complement (SCC) effect on the angiotensin II-sexually dimorphic hypertensive and bradycardic baroreflex responses. We sought to evaluate whether SCC may differentially modulate sexually dimorphic-induced sodium appetite and specific brain activity due to physiological stimulation of the rennin angiotensin system. For this purpose, we used the "four core genotype" mouse model, in which the effect of gonadal sex and SCC is dissociated, allowing comparisons of sexually dimorphic traits between XX and XY females as well as in XX and XY males. Gonadectomized mice were sodium depleted by furosemide (50 mg/kg) and low-sodium diet treatment; control groups were administered with vehicle and maintained on normal sodium diet. Twenty-one hours later, the mice were divided into two groups: one group was submitted to the water-2% NaCl choice intake test, while the other group was perfused and their brains subjected to the Fos-immunoreactivity (FOS-ir) procedure. Sodium depletion, regardless of SCC (XX or XY), induced a significantly lower sodium and water intake in females than in males, confirming the existence in mice of sexual dimorphism in sodium appetite and the organizational involvement of gonadal steroids. Moreover, our results demonstrate a SCC effect on induced brain FOS-ir, showing increased brain activity in XX-SCC mice at the paraventricular nucleus, nucleus of the solitary tract, and lateral parabrachial nucleus, as well as an XX-SCC augmented effect on sodium depletion-induced brain activity at two circumventricular organs, the subfornical organ and area postrema, nuclei closely involved in fluid and blood pressure homeostasis. PMID:24259464

  3. Antimycin A induces death of the human pulmonary fibroblast cells via ROS increase and GSH depletion.

    PubMed

    Park, Woo Hyun; You, Bo Ra

    2016-02-01

    Antimycin A (AMA) inhibits the growth of various cells via stimulating oxidative stress-mediated death. However, little is known about the anti-growth effect of AMA on normal primary lung cells. Here, we investigated the effects of AMA on cell growth inhibition and death in human pulmonary fibroblast (HPF) cells in relation to reactive oxygen species (ROS) and glutathione (GSH) levels. AMA inhibited the growth of HPF cells with an IC50 of ~150 µM at 24 h. AMA induced a G1 phase arrest of the cell cycle and it also triggered apoptosis accompanied by the loss of mitochondrial membrane potential (MMP; ∆Ψm). AMA increased ROS levels including O2᛫- in HPF cells from the early time point of 25 min. It induced GSH depletion in HPF cells in a dose-dependent manner. Z-VAD (a pan-caspase inhibitor) did not significantly prevent cell death and MMP (∆Ψm) loss induced by AMA. N-acetylcysteine (NAC; an antioxidant) attenuated cell growth inhibition, death and MMP (∆Ψm) loss in AMA-treated HPF cells and NAC generally decreased the ROS level in these cells as well. Vitamin C enhanced cell growth inhibition, death, GSH depletion and O2᛫- levels in 100 µM AMA-treated HPF cells whereas this agent strongly attenuated these effects in 200 µM AMA-treated cells. In conclusion, AMA inhibited the growth of HPF cells via apoptosis as well as a G1 phase arrest of the cell cycle. AMA-induced HPF cell death was related to increased ROS levels and GSH depletion. PMID:26647857

  4. Methylone-induced hyperthermia and lethal toxicity: role of the dopamine and serotonin transporters.

    PubMed

    Piao, Ying-Shan; Hall, Frank Scott; Moriya, Yuki; Ito, Miki; Ohara, Arihisa; Kikura-Hanajiri, Ruri; Goda, Yukihiro; Lesch, Klaus-Peter; Murphy, Dennis L; Uhl, George R; Sora, Ichiro

    2015-06-01

    Methylone (2-methylamino-1-[3,4-methylenedioxy-phenyl]propan-1-one), an amphetamine analog, has emerged as a popular drug of abuse worldwide. Methylone induces hyperthermia, which is thought to contribute toward the lethal consequences of methylone overdose. Methylone has been assumed to induce hyperthermic effects through inhibition of serotonin and/or dopamine transporters (SERT and DAT, respectively). To examine the roles of each of these proteins in methylone-induced toxic effects, we used SERT and DAT knockout (KO) mice and assessed the hyperthermic and lethal effects caused by a single administration of methylone. Methylone produced higher rates of lethal toxicity compared with other amphetamine analogs in wild-type mice. Compared with wild-type mice, lethality was significantly lower in DAT KO mice, but not in SERT KO mice. By contrast, only a slight diminution in the hyperthermic effects of methylone was observed in DAT KO mice, whereas a slight enhancement of these effects was observed in SERT KO mice. Administration of the selective D1 receptor antagonist SCH 23390 and the D2 receptor antagonist raclopride reduced methylone-induced hyperthermia, but these drugs also had hypothermic effects in saline-treated mice, albeit to a smaller extent than the effects observed in methylone-treated mice. In contradistinction to 3,4-methylenedioxymethamphetamine, which induces its toxicity through SERT and DAT, these data indicate that DAT, but not SERT, is strongly associated with the lethal toxicity produced by methylone, which did not seem to be dependent on the hyperthermic effects of methylone. DAT is therefore a strong candidate molecule for interventions aimed at preventing acute neurotoxic and lethal effects of methylone. PMID:25794333

  5. Subchronic methamphetamine treatment enhances ouabain-induced striatal dopamine efflux in vivo.

    PubMed

    Kanzaki, A; Akiyama, K; Otsuki, S

    1992-01-13

    The effect of manipulation of the Na+ gradient between the intracellular and extracellular media on striatal dopamine (DA) efflux under steady-state conditions after subchronic methamphetamine (MAP) treatment was investigated. Rats were injected with 4 mg/kg MAP or saline (i.p.), once daily for 14 days. Seven days after the last injection, ouabain (10(-4) M), a selective inhibitor of the Na+,K(+)-ATPase, was infused locally through a semi-permeable probe in the striatum. Ouabain induced a significantly greater (P less than 0.01) increase of the DA concentrations in the striatal perfusate in the subchronic MAP than the control group. The levels of 3,4-dihydroxyphenylacetic acid (DOPAC) (P less than 0.05) and 5-hydroxyindoleacetic acid (5-HIAA) (P less than 0.05) were significantly higher in the subchronic MAP than in the control group. Reserpine pretreatment (5 mg/kg, i.p.) did not affect the enhanced ouabain-induced DA efflux (P less than 0.01) in the subchronic MAP group, and the levels of DOPAC (P less than 0.01), 5-HIAA (P less than 0.01) and HVA (P less than 0.01) were also significantly higher in the subchronic MAP than in the control group. In contrast, alpha-methyl-p-tyrosine (250 mg/kg, i.p.) pretreatment abolished the ouabain-induced efflux of DA, DOPAC and HVA, but not 5-HIAA, in both groups. Specific striatal [3H]ouabain binding and striatal Na+,K(+)-ATPase activity in the subchronic MAP and control groups did not differ significantly. These results suggest that subchronic MAP treatment facilitates the efflux of newly synthesized DA, which is induced by the ouabain-induced decrease of the Na+ gradient between intracellular and extracellular media.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1371707

  6. Mitotic catastrophe and cell death induced by depletion of centrosomal proteins

    PubMed Central

    Kimura, M; Yoshioka, T; Saio, M; Banno, Y; Nagaoka, H; Okano, Y

    2013-01-01

    Mitotic catastrophe, which refers to cell death or its prologue triggered by aberrant mitosis, can be induced by a heterogeneous group of stimuli, including chromosome damage or perturbation of the mitotic apparatus. We investigated the mechanism of mitotic catastrophe and cell death induced by depletion of centrosomal proteins that perturbs microtubule organization. We transfected cells harboring wild-type or mutated p53 with siRNAs targeting Aurora A, ninein, TOG, TACC3, ?-tubulin, or pericentriolar material-1, and monitored the effects on cell death. Knockdown of Aurora A, ninein, TOG, and TACC3 led to cell death, regardless of p53 status. Knockdown of Aurora A, ninein, and TOG, led to aberrant spindle formation and subsequent cell death, which was accompanied by several features of apoptosis, including nuclear condensation and Annexin V binding in HeLa cells. During this process, cleavage of poly(ADP-ribose) polymerase-1, caspase-3, and caspase-9 was detected, but cleavage of caspase-8 was not. Cell death, monitored by time-lapse imaging, occurred during both interphase and M phase. In cells depleted of a centrosomal protein (Aurora A, ninein, or TOG), the rate of cell death was higher if the cells were cotransfected with siRNA against BubR1 or Mad2 than if they were transfected with siRNA against Bub1 or a control siRNA. These results suggest that metaphase arrest is necessary for the mitotic catastrophe and cell death caused by depletion of centrosomal proteins. Knockdown of centrosomal proteins led to increased phosphorylation of Chk2. Enhanced p-Chk2 localization was also observed at the centrosome in cells arrested in M phase, as well as in the nuclei of dying cells. Cotransfection of siRNAs against Chk2, in combination with depletion of a centrosomal protein, decreased the amount of cell death. Thus, Chk2 activity is indispensable for apoptosis after mitotic catastrophe induced by depletion of centrosomal proteins that perturbs microtubule organization. PMID:23598415

  7. Brain-derived neurotrophic factor inhibits apoptosis and dopamine-induced free radical production in striatal neurons but does not prevent cell death.

    PubMed

    Petersn A, A; Larsen, K E; Behr, G G; Romero, N; Przedborski, S; Brundin, P; Sulzer, D

    In hereditary Huntington's disease, a triplet repeat disease, there is extensive loss of striatal neurons. It has been shown that brain-derived neurotrophic factor (BDNF) protects striatal neurons against a variety of insults. We confirmed that BDNF enhances survival and DARPP-32 expression in primary striatal cultures derived from postnatal mice. Furthermore, BDNF inhibited intracellular oxyradical stress triggered by dopamine, and partially blocked basal and dopamine-induced apoptosis. Nevertheless, BDNF failed to rescue striatal neurons from dopamine-induced cell death. Therefore, BDNF inhibits free radical and apoptotic pathways in medium spiny neurons, but does so downstream from the point of commitment to cell death. PMID:11719268

  8. Purinergic mechanisms of lateral parabrachial nucleus facilitate sodium depletion-induced NaCl intake.

    PubMed

    Menezes, Miguel F; Barbosa, Silas P; De Andrade, Carina A F; Menani, Jos V; De Paula, Patrcia M

    2011-02-01

    Purinergic receptors are present in the lateral parabrachial nucleus (LPBN), a pontine structure involved in the control of sodium intake. In the present study, we investigated the effects of ?,?-methyleneadenosine 5'-triphosphate (?,?-methylene ATP, selective P2X purinergic agonist) alone or combined with pyridoxalphosphate-6-azophenyl-2',4'-disulfonic acid (PPADS, P2X purinergic antagonist) or suramin (non-selective P2 purinergic antagonist) injected into the LPBN on sodium depletion-induced 1.8% NaCl intake. Male Holtzman rats with stainless steel cannulas implanted into the LPBN were used. Sodium depletion was induced by treating rats with the diuretic furosemide (20mg/kg of body weight) followed by 24h of sodium-deficient diet. Bilateral injections of ?,?-methylene ATP (2.0 and 4.0nmol/0.2?l) into the LPBN increased sodium depletion-induced 1.8% NaCl intake (25.30.8 and 26.50.9ml/120min, respectively, vs. saline: 15.21.3ml/120min). PPADS (4nmol/0.2?l) alone into the LPBN did not change 1.8% NaCl intake, however, pretreatment with PPADS into the LPBN abolished the effects of ?,?-methylene ATP on 1.8% NaCl intake (16.90.9ml/120min). Suramin (2.0nmol/0.2?l) alone into the LPBN reduced sodium depletion-induced 1.8% NaCl intake (5.71.9ml/120min, vs. saline: 15.51.1ml/120min), without changing 2% sucrose intake or 24h water deprivation-induced water intake. The combination of suramin and ?,?-methylene ATP into the LPBN produced no change of 1.8% NaCl intake (15.21.2ml/120min). The results suggest that purinergic P2 receptor activation in the LPBN facilitates NaCl intake, probably by restraining LPBN mechanisms that inhibit sodium intake. PMID:21129366

  9. Dopamine and serotonin release in the nucleus accumbens during starvation-induced hyperactivity.

    PubMed

    Verhagen, Linda A W; Luijendijk, Mieneke C M; Korte-Bouws, Gerdien A H; Korte, S Mechiel; Adan, Roger A H

    2009-05-01

    Activity-based anorexia (ABA) is considered an animal model for anorexia nervosa (AN). By scheduled feeding and voluntary wheel running, it mimics severe body weight loss and increased physical activity in AN. Pharmacological, genetic and imaging studies implicate dopamine and serotonin in the regulation of feeding behavior, food-anticipatory activity, and food reward. Previous studies propose that the nucleus accumbens (NAc) plays an important role in these food-related processes. Here we determined dopamine and serotonin levels in the NAc upon exposure to the ABA model. Surprisingly, the release of dopamine and serotonin in the NAc were not increased during the initiation of food-anticipatory behavior in ABA rats. Dopamine release in the NAc was increased during feeding behavior in ABA rats. During ABA, levels of serotonin were low and circadian activity is blunted. We conclude that during the early stages of development of food-anticipatory activity, increased dopamine does not trigger hyperactivity. PMID:19181487

  10. Zinc protects human kidney cells from depleted uranium-induced apoptosis.

    PubMed

    Hao, Yuhui; Ren, Jiong; Liu, Cong; Li, Hong; Liu, Jing; Yang, Zhangyou; Li, Rong; Su, Yongping

    2014-03-01

    Depleted uranium (DU) is a weak radioactive heavy metal, and zinc (Zn) is an effective antidote to heavy metal poisoning. However, the effect of Zn on DU-induced cytotoxicity and apoptosis is not completely understood. The purpose of this study was to evaluate the effect of Zn on DU-induced cell apoptosis in human kidney cells (HK-2) and explore its molecular mechanism. Pre-treatment with Zn significantly inhibited DU-induced apoptosis. It reduced the formation of reactive oxygen species in the cells, increased the catalase (CAT) and glutathione (GSH) concentrations, suppressed the DU-induced soluble Fas receptor (sFasR) and soluble Fas ligand (sFasL) overexpression, suppressed the release of cytochrome c and apoptosis inhibitor factor (AIF) from mitochondria to cytoplasm, inhibited the activation of caspase-9, caspase-8 and caspase-3, and induced metallothionein (MT) expression. Furthermore, exogenous MT effectively inhibited DU-induced cell apoptosis. In conclusion, mitochondrial and FasR-mediated apoptosis pathways contribute to DU-induced apoptosis in HK-2 cells. Through independent mechanisms, such as indirect antioxidant effects, inhibition of the activation of caspase-9, caspase-8 and caspase-3, and induction of MT expression, Zn inhibits DU-induced apoptosis. PMID:24330236

  11. Dopamine is a safe antiangiogenic drug which can also prevent 5-fluorouracil induced neutropenia.

    PubMed

    Sarkar, Chandrani; Chakroborty, Debanjan; Dasgupta, Partha Sarathi; Basu, Sujit

    2015-08-01

    The role of vascular endothelial growth factor A (VEGFA) in tumor angiogenesis is well established and accordingly, molecules targeting VEGFA or its receptors are being presently used in the clinics for treatment of several types of cancer. However, these antiangiogenic agents are expensive and have serious side effects. Thus identification of newer drugs with manageable systemic side effects or toxicities is of immense clinical importance. Since we have reported earlier that dopamine (DA) inhibits VEGFA induced angiogenesis in experimental tumor models, we therefore sought to investigate whether DA treatment results in similar toxicities like other antiangiogenic agents. Our results indicated that unlike sunitinib, another commonly used antiangiogenic agent in the clinics which targets VEGF receptors, DA [50 mg/kg/days × 7days intraperitoneally (i.p.)] not only could inhibit tumor angiogenesis and growth of HT29 human colon cancer and LLC (Lewis lung carcinoma) in mice, it also did not cause hypertension, hematological, renal and hepatic toxicities in normal, HT29 and LLC tumor bearing animals. Furthermore and interestingly, in contrast to the currently used antiangiogenic agents, DA also prevented 5-fluorouracil (5FU) induced neutropenia in HT29 colon cancer bearing mice. This action of DA was through inhibition of 5FU mediated suppression of colony forming unit-granulocyte macrophage colony forming units in the bone marrow. Thus our results indicate that DA may be safely used as an antiangiogenic drug for the treatment of malignant tumors. PMID:25556636

  12. Central dopamine receptors mediating pergolide-induced elevation of serum corticosterone in rats. Characterization by the use of antagonists.

    PubMed

    Fuller, R W; Snoddy, H D

    1984-12-01

    Fourteen dopamine antagonists were compared for their ability to antagonize the elevation of the concentration of serum corticosterone in rats by pergolide, a dopamine agonist. Clozapine did not antagonize the effect of pergolide at the largest dose (10 mg/kg) that could be tested without alteration of basal levels of corticosterone. For the other antagonists, calculation of ED50 values [dose antagonizing by 50% the elevation of corticosterone caused by a 0.3 mg/kg (i.p.) dose of pergolide mesylate] revealed the following order of potency: spiperone greater than loxapine greater than fluphenazine greater than perphenazine greater than flupentixol greater than haloperidol greater than cyclophenazine greater than zotepine greater than flumezapine greater than molindone greater than metoclopramide greater than chlorpromazine greater than sulpiride. All of these compounds caused increases in the concentration of the dopamine metabolites, 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA), in the brains of rats. The dose that increased the concentration of DOPAC to 200% of the control value (ED200) was calculated for each compound. The ratio of the ED50 value for antagonism of the elevation of corticosterone induced by pergolide to the ED200 value for the elevation of DOPAC in brain varied, probably related to differing selectivity for pre- versus postsynaptic dopamine receptors between the compounds.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:6527743

  13. Individual differences in frontal cortical thickness correlate with the d-amphetamine-induced striatal dopamine response in humans.

    PubMed

    Casey, Kevin F; Cherkasova, Mariya V; Larcher, Kevin; Evans, Alan C; Baker, Glen B; Dagher, Alain; Benkelfat, Chawki; Leyton, Marco

    2013-09-18

    The meso-striatal dopamine system influences responses to rewards and the motivation to seek them out. Marked individual differences in these responses are seen in laboratory animals, related in part to input from the prefrontal cortex. Here we measured the relation between cortical morphology and drug-induced striatal dopamine release in healthy young people. Participants were 24 (17 male, 7 female; age 23.0 ± 6.2 years) stimulant drug-naive subjects who underwent PET [(11)C]raclopride scans with 0.3 mg/kg d-amphetamine orally and placebo, and an anatomical MRI scan for measuring cortical thickness. As expected, d-amphetamine produced significant reductions in [(11)C]raclopride binding potential in the striatum as a percentage of the value in the placebo condition. There was substantial individual variability in this response, which was correlated with cortical thickness in the frontal lobe as a whole. The association was strongest in the anterior part of the right lateral prefrontal cortex and bilateral supplementary motor area. A thicker cortex was correlated with a smaller dopamine response. Together, this work demonstrates in humans an association between cortical thickness and the striatal dopamine response to drugs of abuse. Although prefrontal regulation of striatal function has been well studied, it was unclear whether the thickness of the prefrontal cortex was an acceptable proxy to the function of that region. These results suggest it is. PMID:24048857

  14. Sedimentation rapidly induces an immune response and depletes energy stores in a hard coral

    NASA Astrophysics Data System (ADS)

    Sheridan, C.; Grosjean, Ph.; Leblud, J.; Palmer, C. V.; Kushmaro, A.; Eeckhaut, I.

    2014-12-01

    High sedimentation rates have been linked to reduced coral health within multiple systems; however, whether this is a direct result of compromised coral immunity has not been previously investigated. The potential effects of sedimentation on immunity of the hard coral Montipora patula were examined by comparing physiological responses of coral fragments inoculated with sterilized marine sediments and those under control conditions. Sediments were collected from terrestrial runoff-affected reefs in SW Madagascar and applied cyclically for a total of 24 h at a rate observed during precipitation-induced sedimentation events. Coral health was determined 24 h after the onset of the sedimentation stress through measuring metabolic proxies of O2 budget and lipid ratios. Immune response of the melanin synthesis pathway was measured by quantifying phenoloxidase activity and melanin deposits. Sedimentation induced both immune and metabolic responses in M. patula. Both phenoloxidase activity and melanin deposition were significantly higher in the sediment treatment compared to controls, indicating an induced immune response. Sediment-treated corals also showed a tendency towards increased respiration (during the night) and decreased photosynthesis (during the day) and a significant depletion of energy reserves as compared to controls. These data highlight that short-term (24 h) sedimentation, free of live microorganisms, compromises the health of M. patula. The energetically costly immune response, potentially elicited by residual endotoxins and other inflammatory particles associated with the sterile sediments, likely contributes to the energy depletion. Overall, exposure to sedimentation adversely affects coral health and continued exposure may lead to resource depletion and an increased susceptibility to disease.

  15. Oleic acid-induced lung injury in rabbits: effect of fibrinogen depletion with Arvin

    SciTech Connect

    Allard, M.F.; Doerschuk, C.M.; Brumwell, M.L.; Belzberg, A.; Hogg, J.C.

    1988-03-01

    The role of fibrinogen in the evolution of the increased permeability after oleic acid-induced lung injury was studied in New Zealand White rabbits. Animals depleted of fibrinogen by treatment with Malayan pit viper venom were compared with untreated rabbits immediately and at 1 and 24 h after injury. The increased permeability to albumin and elevated extravascular lung water (EVLW) associated with lung injury returned to control values by 24 h in untreated animals. Fibrinogen-depleted animals had a higher mortality (10/25 vs. 2/17, P less than 0.02) and showed a greater immediate increase in permeability to albumin that returned to control values at 1 and 24 h after injury, as well as trends toward elevated blood-free dry lung weight and larger increases in EVLW that persisted for 24 h. These findings indicate that fibrinogen-related proteins play an important role in controlling the microvascular injury that is produced by oleic acid. However, when these proteins are depleted, other mechanisms partially control the leak at later stages of the repair process.

  16. Auranofin induces mesothelioma cell death through oxidative stress and GSH depletion.

    PubMed

    You, Bo Ra; Park, Woo Hyun

    2016-01-01

    Mesothelioma is an aggressive tumor associated with asbestos exposure. Auranofin as an inhibitor of thioredoxin reductase (TrxR) affects many biological processes such as inflammation and proliferation. In the present study, we investigated the cellular effects of auranofin on patient?derived mesothelioma cells in relation to reactive oxygen species(ROS) and glutathione (GSH) levels. Basal TrxR1 levels have no difference between mesothelial cells and certain mesothelioma cells. In particular, ADA, CON and Hmeso mesothelioma cells showed lower levels of TrxR1 expression. Auranofin inhibited the proliferation of mesothelioma cells in a dose?dependent manner. Among mesothelioma cells were ADA and CON cells sensitive to auranofin. This agent also induced caspase?independent apoptosis and necrosis in ADA cells. In addition, auranofin increased ROS levels including O2? and induced GSH depletion in mesothelioma cells. While N?acetyl cysteine (NAC) prevented cell death and decreased ROS levels in auranofin?treated mesothelioma cells, L?buthionine sulfoximine (BSO) intensified apoptosis and GSH depletion in these cells. In conclusion, auranofin induced mesothelioma cell death through oxidative stress and the death was regulated by the status of GSH content. PMID:26530353

  17. Inhibition of the differentiation of human myeloid cell lines by redox changes induced through glutathione depletion.

    PubMed Central

    Esposito, F; Agosti, V; Morrone, G; Morra, F; Cuomo, C; Russo, T; Venuta, S; Cimino, F

    1994-01-01

    We have investigated the effect of redox changes in vivo on the differentiation of two human myeloid cell lines, HL-60 and KG-1. The glutathione-depleting agent diethyl maleate (DEM) prevented the development of differentiated features in response to phorbol esters, including adherence of the cells to plastic surfaces and repression of the myeloperoxidase and CD34 genes. Moreover, DEM abolished phorbol 12-myristate 13-acetate-induced activation of the transcription factors AP-1 and Egr-1, suggesting that inhibition of differentiation may be due, at least in part, to redox modifications of these proteins. Images Figure 1 Figure 2 Figure 3 Figure 4 PMID:7519845

  18. Analysis of dopamine D1 and D2 receptor involvement in d- and l-amphetamine-induced anorexia in rats.

    PubMed

    Gilbert, D B; Cooper, S J

    1985-10-01

    The concept of dopamine receptor subtypes and the recent development of selective dopamine receptor agonists and antagonists raises the possibility of specific subtype involvement in amphetamine-induced anorexia, and, furthermore, provides the means to evaluate the possibility. Using a test of palatable food consumption by nondeprived male rats, our data confirmed a more potent suppressant effect of d-amphetamine on food intake, compared to l-amphetamine (potency ratio 5.32:1). The test proved sensitive, with ED50s of 0.28 mg/kg and 1.49 mg/kg for d- and l-amphetamine, respectively. The modest anorectic effect of 0.3 mg/kg d-amphetamine was completely reversed by the selective dopamine D1 receptor antagonist, SCH 23390, but was not affected by the selective D2 receptor antagonist, sulpiride. A matched feeding-suppressant effect of 1.0 mg/kg l-amphetamine was reversed at one dose of SCH 23390, but was unaffected by sulpiride. Stronger anorectic effects produced by 1.0 mg/kg d-amphetamine and 3.0 mg/kg l-amphetamine were not antagonized either by SCH 23390 or sulpiride. The selective D1 receptor agonist, SKF 38393, produced a dose-dependent reduction in food consumption, without producing behavioural stereotypy. Unlike amphetamine, SKF 38393 is not self-administered, and therefore may provide an example of a novel pharmacological dissociation between anorectic and reinforcing effects of drug treatments mediated by dopamine receptors. Our data implicate dopamine D1 receptors in the control of feeding responses, and suggest that these receptors may mediate the anorectic effect of small-dose amphetamine treatments. PMID:2933127

  19. Pumping-induced drawdown and stream depletion in a leaky aquifer system

    USGS Publications Warehouse

    Butler, J.J., Jr.; Zhan, X.; Zlotnik, V.A.

    2007-01-01

    The impact of ground water pumping on nearby streams is often estimated using analytic models of the interconnected stream-aquifer system. A common assumption of these models is that the pumped aquifer is underlain by an impermeable formation. A new semianalytic solution for drawdown and stream depletion has been developed that does not require this assumption. This solution shows that pumping-induced flow (leakage) through an underlying aquitard can be an important recharge mechanism in many stream-aquifer systems. The relative importance of this source of recharge increases with the distance between the pumping well and the stream. The distance at which leakage becomes the primary component of the pumping-induced recharge depends on the specific properties of the aquifer, aquitard, and streambed. Even when the aquitard is orders of magnitude less transmissive than the aquifer, leakage can be an important recharge mechanism because of the large surface area over which it occurs. Failure to consider aquitard leakage can lead to large overestimations of both the drawdown produced by pumping and the contribution of stream depletion to the pumping-induced recharge. The ramifications for water resources management and water rights adjudication can be significant. A hypothetical example helps illustrate these points and demonstrates that more attention should be given to estimating the properties of aquitards underlying stream-aquifer systems. The solution presented here should serve as a relatively simple but versatile tool for practical assessments of pumping-induced stream-aquifer interactions. However, this solution should not be used for such assessments without site-specific data that indicate pumping has induced leakage through the aquitard. ?? 2006 National Ground Water Association.

  20. Ganglioside GQ1b induces dopamine release through the activation of Pyk2.

    PubMed

    Zhang, Zhao; Chu, Shi-Feng; Mou, Zheng; Gao, Yan; Wang, Zhen-Zhen; Wei, Gui-Ning; Chen, Nai-Hong

    2016-03-01

    Growing evidence indicates that GQ1b, one of the gangliosides members, contributes to synaptic transmission and synapse formation. Previous studies have shown that GQ1b could enhance depolarization induced neurotransmitter release, while the role of GQ1b in asynchronous release is still largely unknown. Here in our result, we found low concentration of GQ1b, but not GT1b or GD1b (which were generated from GQ1b by plasma membrane-associated sialidases), evoked asynchronous dopamine (DA) release from both clonal rat pheochromocytoma PC12 cells and rat striatal slices significantly. The release peaked at 2min after GQ1b exposure, and lasted for more than 6min. This effect was caused by the enhancement of intracellular Ca(2+) and the activation of Pyk2. Inhibition of Pyk2 by PF-431396 (a dual inhibitor of Pyk2 and FAK) or Pyk2 siRNA abolished DA release induced by GQ1b. Moreover, Pyk2 Y402, but not other tyrosine site, was phosphorylated at the peaking time. The mutant of Pyk2 Y402 (Pyk2-Y402F) was built to confirm the essential role of Y402 activation. Further studies revealed that activated Pyk2 stimulated ERK1/2 and p-38, while only the ERK1/2 activation was indispensable for GQ1b induced DA release, which interacted with Synapsin I directly and led to its phosphorylation, then depolymerization of F-actin, thus contributed to DA release. In conclusion, low concentration of GQ1b is able to enhance asynchronous DA release through Pyk2/ERK/Synapsin I/actin pathway. Our findings provide new insights into the role of GQ1b in neuronal communication, and implicate the potential application of GQ1b in neurological disorders. PMID:26704905

  1. A dopamine receptor contributes to paraquat-induced neurotoxicity in Drosophila

    PubMed Central

    Cassar, Marlène; Issa, Abdul-Raouf; Riemensperger, Thomas; Petitgas, Céline; Rival, Thomas; Coulom, Hélène; Iché-Torres, Magali; Han, Kyung-An; Birman, Serge

    2015-01-01

    Long-term exposure to environmental oxidative stressors, like the herbicide paraquat (PQ), has been linked to the development of Parkinson's disease (PD), the most frequent neurodegenerative movement disorder. Paraquat is thus frequently used in the fruit fly Drosophila melanogaster and other animal models to study PD and the degeneration of dopaminergic neurons (DNs) that characterizes this disease. Here, we show that a D1-like dopamine (DA) receptor, DAMB, actively contributes to the fast central nervous system (CNS) failure induced by PQ in the fly. First, we found that a long-term increase in neuronal DA synthesis reduced DAMB expression and protected against PQ neurotoxicity. Secondly, a striking age-related decrease in PQ resistance in young adult flies correlated with an augmentation of DAMB expression. This aging-associated increase in oxidative stress vulnerability was not observed in a DAMB-deficient mutant. Thirdly, targeted inactivation of this receptor in glutamatergic neurons (GNs) markedly enhanced the survival of Drosophila exposed to either PQ or neurotoxic levels of DA, whereas, conversely, DAMB overexpression in these cells made the flies more vulnerable to both compounds. Fourthly, a mutation in the Drosophila ryanodine receptor (RyR), which inhibits activity-induced increase in cytosolic Ca2+, also strongly enhanced PQ resistance. Finally, we found that DAMB overexpression in specific neuronal populations arrested development of the fly and that in vivo stimulation of either DNs or GNs increased PQ susceptibility. This suggests a model for DA receptor-mediated potentiation of PQ-induced neurotoxicity. Further studies of DAMB signaling in Drosophila could have implications for better understanding DA-related neurodegenerative disorders in humans. PMID:25158689

  2. Depletion of Hepatic Macrophages Aggravates Liver Lesions Induced in Rats by Thioacetamide (TAA).

    PubMed

    Golbar, Hossain M; Izawa, Takeshi; Wijesundera, Kavindra K; Bondoc, Alexandra; Tennakoon, Anusha H; Kuwamura, Mitsuru; Yamate, Jyoji

    2016-02-01

    Hepatic macrophages play crucial roles in hepatotoxicity. We investigated immunophenotypes of macrophages in liver injury induced in rats by thioacetamide (TAA; 300 mg/kg, intraperitoneal) after hepatic macrophage depletion; hepatic macrophages were depleted by liposomal clodronate (CLD; 10 ml/kg, i.v.) one day before TAA injection. Samples were obtained on post-TAA injection days 0, 1, 2, 3, 5, and 7. TAA injection induced coagulation necrosis of hepatocytes on days 1 through 3 and subsequent reparative fibrosis on days 5 and 7 in the centrilobular area, accompanied by increased numbers of M1 macrophages (expressing cluster of differentiation [CD]68 and major histocompatibility complex class II) and M2 macrophages (expressing CD163 and CD204) mainly on days 1 through 3. TAA + CLD treatment markedly decreased the numbers of M1 and M2 macrophages mainly on days 1 through 3; CD163(+) Kupffer cells were most sensitive to CLD depletion. In TAA + CLD-treated rats, interestingly, coagulation necrosis of hepatocytes was prolonged with more increased levels of hepatic enzymes (aspartate transaminase, alanine transaminase, and alkaline phosphatase) to TAA-treated rats; reparative fibrosis was incomplete and replaced by dystrophic calcification in the injured area, indicating the aggravated damage. Furthermore, in TAA + CLD-treated rats, inflammatory factors (monocyte chemoattractant protein [MCP]-1, interferon-γ, tumor necrosis factor-α, and interleukin-10) and fibrosis-related factors (transforming growth factor-β1, matrix metalloproteinase-2, tissue inhibitor of metalloproteinase-1) were decreased at messenger RNA levels, indicating abnormal macrophage functions. It was clearly demonstrated that hepatic macrophages have important roles in tissue damage and remodeling in hepatotoxicity. PMID:26957569

  3. Selective effects of buspirone and molindone on dopamine metabolism and function in the striatum and frontal cortex of the rat.

    PubMed

    McMillen, B A; McDonald, C C

    1983-03-01

    The hypothesis that the nerve endings of the dopamine projection of the frontal cortex lack autoreceptors for regulation of tyrosine hydroxylase was tested by using the preferential inhibitors of dopamine autoreceptors, molindole and buspirone. In contrast to haloperidol, which elevates dopamine metabolism in the striatum and frontal cortex, both molindone and buspirone elicited little change in dopamine metabolism in the frontal cortex at doses up to 3.0 mg/kg, which cause the same maximal response in the corpus striatum as does haloperidol. Thus, the lack of autoreceptors in the frontal cortex is of pharmacological importance. That preferential inhibition of striatal dopamine autoreceptors may reverse catalepsy by enhancing synthesis and release of dopamine was tested by first inducing catalepsy with different drugs and then administering molindone or buspirone. Only buspirone (1.0 mg/kg) reversed catalepsy. This effect does not require presynaptic dopamine as catalepsy was reversed by buspirone in the dopamine-depleted rat (with 2.0 mg/kg R04-1284) as well as after postsynaptic dopamine receptor blockade by haloperidol of cis-flupenthixol. Thus, the mechanism for the reversal of catalepsy appears to be located efferent from the dopamine neuron. Buspirone, a non-benzodiazepine anti-anxiety drug, may prove useful for treatment of extrapyramidal motor disorders of either iatrogenic or idiosyncratic origin. PMID:6133232

  4. Tamoxifen counteracts estradiol induced effects on striatal and hypophyseal dopamine receptors

    SciTech Connect

    Ferretti, C.; Blengio, M.; Ghi, P.; Racca, S.; Genazzani, E.; Portaleone, P.

    1988-01-01

    We investigated the ability of Tamoxifen (TAM), an antiestrogen drug, to counteract the modification induced by estrogens on dopamine (DA) receptors on striatum and on adenohypophysis of ovex female rats. Subacute treatment with 17..beta..-estradiol (E/sub 2/) at both low (0.1 ..mu..g/kg) and high (20 ..mu..g/kg) doses confirmed its ability to increase the number of striatal /sup 3/H-Spiperone (/sup 3/H-SPI) binding sites in a dose dependent manner. By contrast in the pituitary, only high doses of estrogen were effective in reducing the number of DA receptors. We treated ovex female rats for 15 days with TAM alone or associated with E/sub 2/, to see if these estrogenic effects could be suppressed by an antiestrogenic drug. TAM did not affect the number of striatal DA receptors, but significantly increased the adenohypophy-seal DA binding sites, without varying their affinity. No changes were observed in pituitary and striatal DA receptor density, even when TAM was injected in association with estradiol. In conclusions: TAM is able to counteract the effects estrogens have on DA receptors. However there is some evidence that it could influence the pituitary DA systems independently of it antiestrogenic activity.

  5. Telomerase abrogates aneuploidy-induced telomere replication stress, senescence and cell depletion

    PubMed Central

    Meena, Jitendra K; Cerutti, Aurora; Beichler, Christine; Morita, Yohei; Bruhn, Christopher; Kumar, Mukesh; Kraus, Johann M; Speicher, Michael R; Wang, Zhao-Qi; Kestler, Hans A; dAdda di Fagagna, Fabrizio; Gnes, Cagatay; Rudolph, Karl Lenhard

    2015-01-01

    The causal role of aneuploidy in cancer initiation remains under debate since mutations of euploidy-controlling genes reduce cell fitness but aneuploidy strongly associates with human cancers. Telomerase activation allows immortal growth by stabilizing telomere length, but its role in aneuploidy survival has not been characterized. Here, we analyze the response of primary human cells and murine hematopoietic stem cells (HSCs) to aneuploidy induction and the role of telomeres and the telomerase in this process. The study shows that aneuploidy induces replication stress at telomeres leading to telomeric DNA damage and p53 activation. This results in p53/Rb-dependent, premature senescence of human fibroblast, and in the depletion of hematopoietic cells in telomerase-deficient mice. Endogenous telomerase expression in HSCs and enforced expression of telomerase in human fibroblasts are sufficient to abrogate aneuploidy-induced replication stress at telomeres and the consequent induction of premature senescence and hematopoietic cell depletion. Together, these results identify telomerase as an aneuploidy survival factor in mammalian cells based on its capacity to alleviate telomere replication stress in response to aneuploidy induction. PMID:25820263

  6. Norcantharidin induced DU145 cell apoptosis through ROS-mediated mitochondrial dysfunction and energy depletion.

    PubMed

    Shen, Bo; He, Pei-Jie; Shao, Chun-Lin

    2013-01-01

    Norcantharidin (NCTD), a demethylated analog of cantharidin derived from blister beetles, has attracted considerable attentions in recent years due to their definitely toxic properties and the noteworthy advantages in stimulating bone marrow and increasing the peripheral leukocytes. Hence, it is worth studying the anti-tumor effect of NCTD on human prostate cancer cells DU145. It was found that after the treatment of NCTD with different concentrations (25-100 ?M), the cell proliferation was significantly inhibited, which led to the appearance of micronucleus (MN). Moreover, the cells could be killed in a dose-/time-dependent manner along with the reduction of PCNA (proliferating cell nuclear antigen) expression, destruction of mitochondrial membrane potential (MMP), down-regulation of MnSOD, induction of ROS, depletion of ATP, and activation of AMPK (Adenosine 5'-monophosphate -activated protein kinase) . In addition, a remarkable release of cytochrome c was found in the cells exposed to 100 ?M NCTD and exogenous SOD-PEG could eliminate the generation of NCTD-induced MN. In conclusion, our studies indicated that NCTD could induce the collapse of MMP and mitochondria dysfunction. Accumulation of intercellular ROS could eventually switch on the apoptotic pathway by causing DNA damage and depleting ATP. PMID:24367681

  7. Norcantharidin Induced DU145 Cell Apoptosis through ROS-Mediated Mitochondrial Dysfunction and Energy Depletion

    PubMed Central

    Shao, Chun-Lin

    2013-01-01

    Norcantharidin (NCTD), a demethylated analog of cantharidin derived from blister beetles, has attracted considerable attentions in recent years due to their definitely toxic properties and the noteworthy advantages in stimulating bone marrow and increasing the peripheral leukocytes. Hence, it is worth studying the anti-tumor effect of NCTD on human prostate cancer cells DU145. It was found that after the treatment of NCTD with different concentrations (25-100 ?M), the cell proliferation was significantly inhibited, which led to the appearance of micronucleus (MN). Moreover, the cells could be killed in a dose-/ time-dependent manner along with the reduction of PCNA (proliferating cell nuclear antigen) expression, destruction of mitochondrial membrane potential (MMP), down-regulation of MnSOD, induction of ROS, depletion of ATP, and activation of AMPK (Adenosine 5-monophosphate -activated protein kinase) . In addition, a remarkable release of cytochrome c was found in the cells exposed to 100 ?M NCTD and exogenous SOD-PEG could eliminate the generation of NCTD-induced MN. In conclusion, our studies indicated that NCTD could induce the collapse of MMP and mitochondria dysfunction. Accumulation of intercellular ROS could eventually switch on the apoptotic pathway by causing DNA damage and depleting ATP. PMID:24367681

  8. Modulation of Bleomycin-Induced Lung Fibrosis by Pegylated Hyaluronidase and Dopamine Receptor Antagonist in Mice

    PubMed Central

    Pershina, Olga Victorovna; Reztsova, Alena Mikhaylovna; Ermakova, Natalia Nikolaevna; Khmelevskaya, Ekaterina Sergeevna; Krupin, Vycheslav Andreevich; Stepanova, Inna Ernestovna; Artamonov, Andrew Vladimirovich; Bekarev, Andrew Alexandrovich; Madonov, Pavel Gennadjevich

    2015-01-01

    Hyaluronidases are groups of enzymes that degrade hyaluronic acid (HA). To stop enzymatic hydrolysis we modified testicular hyaluronidase (HYAL) by activated polyethylene oxide with the help of electron-beam synthesis. As a result we received pegylated hyaluronidase (pegHYAL). Spiperone is a selective D2 dopamine receptor antagonist. It was demonstrated on the model of a single bleomycin damage of alveolar epithelium that during the inflammatory phase monotherapy by pegHYAL or spiperone reduced the populations of hematopoietic stem /progenitor cells in the lung parenchyma. PegHYAL also reduced the levels of transforming growth factor (TGF)-β, interleukin (IL)-1β, tumor necrosis factor (TNF)-α in the serum and lungs, while spiperone reduced the level of the serum IL-1β. Polytherapy by spiperone and pegHYAL caused the increase of the quantity of hematopoietic stem/ progenitor cells in the lungs. Such an influx of blood cell precursors was observed on the background of considerable fall level of TGF-β and the increase level of TNF-α in the serum and lungs. These results show pegHYAL reduced the bleomycin-induced fibrosis reaction (production and accumulation of collagen) in the lung parenchyma. This effect was observed at a single and repetitive bleomycin damage of alveolar epithelium, the antifibrotic activity of pegHYAL surpassing the activity of testicular HYAL. The antifibrotic effect of pegHYAL is enhanced by an additional instillation of spiperone. Therapy by pegHYAL causes the flow of CD31‒CD34‒CD45‒CD44+CD73+CD90+CD106+-cells into the fibrous lungs. These cells are incapable of differentiating into fibroblast cells. Spiperone instillation separately or together with pegHYAL reduced the MSC-like cells considerably. These data enable us to assume, that pegHYAL is a new and promising instrument both for preventive and therapy of toxic pneumofibrosis. The blockage of D2 dopamine receptors with the following change of hyaluronan matrix can be considered as a new strategy in treatment of pneumofibrosis. PMID:25927611

  9. N-Terminal Phosphorylation of the Dopamine Transporter Is Required for Amphetamine-Induced Efflux

    PubMed Central

    2004-01-01

    Amphetamine (AMPH) elicits its behavioral effects by acting on the dopamine (DA) transporter (DAT) to induce DA efflux into the synaptic cleft. We previously demonstrated that a human DAT construct in which the first 22 amino acids were truncated was not phosphorylated by activation of protein kinase C, in contrast to wild-type (WT) DAT, which was phosphorylated. Nonetheless, in all functions tested to date, which include uptake, inhibitor binding, oligomerization, and redistribution away from the cell surface in response to protein kinase C activation, the truncated DAT was indistinguishable from the full-length WT DAT. Here, however, we show that in HEK-293 cells stably expressing an N-terminal-truncated DAT (del-22 DAT), AMPH-induced DA efflux is reduced by approximately 80%, whether measured by superfusion of a population of cells or by amperometry combined with the patch-clamp technique in the whole cell configuration. We further demonstrate in a full-length DAT construct that simultaneous mutation of the five N-terminal serine residues to alanine (S/A) produces the same phenotype as del-22normal uptake but dramatically impaired efflux. In contrast, simultaneous mutation of these same five serines to aspartate (S/D) to simulate phosphorylation results in normal AMPH-induced DA efflux and uptake. In the S/A background, the single mutation to Asp of residue 7 or residue 12 restored a significant fraction of WT efflux, whereas mutation to Asp of residues 2, 4, or 13 was without significant effect on efflux. We propose that phosphorylation of one or more serines in the N-terminus of human DAT, most likely Ser7 or Ser12, is essential for AMPH-induced DAT-mediated DA efflux. Quite surprisingly, N-terminal phosphorylation shifts DAT from a reluctant state to a willing state for AMPH-induced DA efflux, without affecting inward transport. These data raise the therapeutic possibility of interfering selectively with AMPH-induced DA efflux without altering physiological DA uptake. PMID:15024426

  10. Maitotoxin-induced myocardial cell injury: Calcium accumulation followed by ATP depletion precedes cell death

    SciTech Connect

    Santostasi, G.; Kutty, R.K.; Bartorelli, A.L.; Yasumoto, T.; Krishna, G. )

    1990-01-01

    Maitotoxin, the most potent marine toxin, is known to increase the uptake and the accumulation of Ca2+ into cells, and was used in the present study to investigate the mechanisms of myocardial cell damage induced by Ca2+ overload. In cultured cardiomyocytes, isolated from 2-day-old rats, maitotoxin affected cell viability, as indicated by the leakage of the cytosolic enzyme lactate dehydrogenase (LDH) and of radiolabeled adenine nucleotides into the extracellular medium. Maitotoxin-induced leakage of LDH steadily increased between 30 min and 24 hr, and was preceded by a marked depletion of intracellular ATP. Addition of maitotoxin resulted in a rapid influx of extracellular Ca2+, as detected by preincubating the cells in the presence of 45Ca; this effect evolved in a few minutes, thus preceding the signs of cell death. Cytosolic levels of free Ca2+ ((Ca2+)i) were monitored by loading freshly isolated, suspended cardiomyocytes with the intracellular fluorescent probe fura-2; in these cells, maitotoxin induced a dose-dependent increase in (Ca2+)i, with a lag phase of less than a minute. All these effects of maitotoxin were inhibited by reducing Ca2+ concentration in the culture medium or by incubating the cells with the calcium-channel blocking drug verapamil. It is thus demonstrated that maitotoxin-induced cardiotoxicity is secondary to an inordinate influx of Ca2+ into the cells. It is also suggested that, in those conditions that lead to an inordinate accumulation of Ca2+ into myocardial cells, the unmatched demands of energy and the depletion of ATP play a primary role in the irreversible stage of cell damage.

  11. Electrically induced release of endogenous noradrenaline and dopamine from brain slices: pseudo-one-pulse stimulation utilized to study presynaptic autoinhibition.

    PubMed

    Thienprasert, A; Singer, E A

    1993-08-01

    Slices of rat hypothalamus (noradrenaline experiments) or rabbit caudate nucleus (dopamine experiments) were prepared, superfused, and field-stimulated using series of monophasic rectangular pulses. Noradrenaline, dopamine and the main dopamine metabolite, dihydroxyphenylacetic acetic acid (DOPAC), were determined using HPLC with electrochemical detection. Electrical stimulation was performed using the following protocols: 1) 4 pulses delivered at 100 Hz; this type of stimulation is referred to as pseudo-one-pulse stimulation (POP); its short duration of only 32 ms does not allow the development of autoinhibition; 2) 2 bursts of 4 pulses at 100 Hz, delivered 1 s apart (2-POP-stimulation); 3) 8 pulses at 1 Hz (dopamine experiments only); 4) 36 pulses at 3 Hz. Noradrenaline experiments. The alpha 2-adrenoceptor antagonist yohimbine (1 mumol/l) did not enhance noradrenaline overflow following POP stimulation, but enhanced the overflow following 2-POP-stimulation by about 50% and that following 36-pulse-stimulation by almost 100%. Dopamine experiments. The D2-dopamine receptor antagonist sulpiride (3 mumol/l) facilitated the overflow of dopamine elicited with 2-POP-stimulation (66%), 8 pulses/1 Hz (92%), and 36 pulses/3 Hz (140%). It did not significantly facilitate the overflow of dopamine following POP-stimulation (19%). The overflow of DOPAC was not, or only slightly, increased by electrical stimulation, and its spontaneous outflow was more than three times higher than that of dopamine. Furthermore, the electrically induced overflow of dopamine did not exceed the outflow of DOPAC at any of the stimulation conditions employed. The results of the present study bear out important claims of the autoreceptor theory and confirm the data obtained in previous experiments using labelled transmitters. PMID:8232591

  12. Modulation of cue-induced firing of ventral tegmental area dopamine neurons by leptin and ghrelin

    PubMed Central

    van der Plasse, G; van Zessen, R; Luijendijk, M C M; Erkan, H; Stuber, G D; Ramakers, G M J; Adan, R A H

    2015-01-01

    Background/objectives: The rewarding value of palatable foods contributes to overconsumption, even in satiated subjects. Midbrain dopaminergic activity in response to reward-predicting environmental stimuli drives reward-seeking and motivated behavior for food rewards. This mesolimbic dopamine (DA) system is sensitive to changes in energy balance, yet it has thus far not been established whether reward signaling of DA neurons in vivo is under control of hormones that signal appetite and energy balance such as ghrelin and leptin. Subjects/methods: We trained rats (n=11) on an operant task in which they could earn two different food rewards. We then implanted recording electrodes in the ventral tegmental area (VTA), and recorded from DA neurons during behavior. Subsequently, we assessed the effects of mild food restriction and pretreatment with the adipose tissue-derived anorexigenic hormone leptin or the orexigenic hormone ghrelin on VTA DA reward signaling. Results: Animals showed an increase in performance following mild food restriction (P=0.002). Importantly, food-cue induced DA firing increased when animals were food restricted (P=0.02), but was significantly attenuated after leptin pretreatment (P=0.00). While ghrelin did affect baseline DA activity (P=0.025), it did not affect cue-induced firing (P⩾0.353). Conclusions: Metabolic signals, such as leptin, affect food seeking, a process that is dependent on the formation of cue-reward outcomes and involves midbrain DA signaling. These data show that food restriction engages the encoding of food cues by VTA DA neurons at a millisecond level and leptin suppresses this activity. This suggests that leptin is a key in linking metabolic information to reward signaling. PMID:26183405

  13. Measurement of Beta Particles Induced Electron-Hole Pairs Recombination in Depletion Region of GaAs PN Junction

    NASA Astrophysics Data System (ADS)

    Chen, Hai-Yang; Jiang, Lan; Li, Da-Rang

    2011-05-01

    PN junctions and schottky diodes are widely employed as electron-hole pair collectors in electron beam induced current (EBIC) techniques and betavoltaic batteries, in which the recombination in depletion regions is ignored. We measured the beta particles induced electron-hole pairs recombination in the depletion region of a GaAs P+PN+ junction, based on comparisons between measured short currents and ideal values. The results show that only 20% electron-hole pairs in the depletion can be collected, causing the short current. This indicates an electron-hole pair diffusion length of 0.2?m in the depletion region. Hence, it is necessary to evaluate the recombination in the EBIC techniques and betavoltaic design.

  14. Growth Hormone Induces Transforming Growth Factor-Beta-Induced Protein in Podocytes: Implications for Podocyte Depletion and Proteinuria.

    PubMed

    Chitra, P Swathi; Swathi, T; Sahay, Rakesh; Reddy, G Bhanuprakash; Menon, Ram K; Kumar, P Anil

    2015-09-01

    The glomerular podocytes form a major size selective barrier for the filtration of serum proteins and reduced podocyte number is a critical event in the pathogenesis of proteinuria during diabetic nephropathy (DN). An elevated level of growth hormone (GH) is implicated as a causative factor in the development of nephropathy in patients with type 1 diabetes mellitus. We have previously shown that podocytes express GH receptor and are a target for GH action. To elucidate the molecular basis for the effects of GH on podocyte depletion, we conducted PCR-array analyses for extracellular matrix and adhesion molecules in podocytes. Our studies reveal that GH increases expression of a gene that encodes transforming growth factor-beta-induced protein (TGFBIp) expression. Similarly, microarray data retrieved from the Nephromine database revealed elevation of TGFBIp in patients with DN. Treatment with GH results in increased secretion of extracellular TGFBIp by podocytes. Both GH and TGFBIp induced apoptosis and epithelial mesenchymal transition (EMT) of podocytes. Exposure of podocytes to GH and TGFBIp resulted in increased migration of cells and altered podocyte permeability to albumin across podocyte monolayer. Administration of GH to rats induced EMT and apoptosis in the glomerular fraction of the kidney. Therefore, we conclude that the GH-dependent increase in TGFBIp in the podocyte is one of the mechanisms responsible for podocyte depletion in DN. PMID:25740786

  15. Acute ozone-induced lung injury in neutrophil-depleted rats

    SciTech Connect

    Pino, M.V.; Stovall, M.Y.; Levin, J.R.; Devlin, R.B.; Koren, H.S.; Hyde, D.M. )

    1992-06-01

    To test the hypothesis that neutrophils contribute to acute, ozone-induced epithelial damage in the lung, rats were depleted of their circulating neutrophils by intraperitoneal injection of a rabbit anti-rat neutrophil serum (ANS) 12 hr prior to an 8-hr exposure to 1.0 ppm ozone. Additional rats were given an injection of normal rabbit serum (NRS) prior to ozone exposure. Exposures were followed by postexposure periods in filtered air for 0, 4, or 16 hr. Control rats were given either ANS or NRS and then exposed only to filtered air. Analysis of bronchoalveolar lavage fluid (BALF) from NRS-treated rats revealed a significant increase in total neutrophils above that of controls at the 4- and 16-hr postexposure times, with a peak increase at 4 hr postexposure. In contrast, there was almost total ablation of the BALF neutrophil response in the ANS-treated rats at all times. Ozone caused an increase in BALF protein, fibronectin, and interleukin-6 above those in controls in both the NRS- and ANS-treated rats, but the only significant difference between the two groups was a level of fibronectin in the neutrophil-depleted animals higher than that in the neutrophil-sufficient animals at the 0-hr postexposure time. Electron microscopic morphometry on lungs fixed by intravascular perfusion demonstrated no significant differences in the volume per surface area epithelial basal lamina (Vs) of necrotic and degenerating epithelial cells in central acini between the neutrophil-depleted and neutrophil-sufficient animals. From these results, we concluded that neutrophils do not play a detectable role in contributing to the early epithelial damage in the lung caused by an acute exposure to ozone.

  16. Gastric mucosal lesions induced by complete dopamine system failure in rats. The effects of dopamine agents, ranitidine, atropine, omeprazole and pentadecapeptide BPC 157.

    PubMed

    Sikiric, P; Separovic, J; Buljat, G; Anic, T; Stancic-Rokotov, D; Mikus, D; Duplancic, B; Marovic, A; Zoricic, I; Prkacin, I; Lovric-Bencic, M; Aralica, G; Ziger, T; Perovic, D; Jelovac, N; Dodig, G; Rotkvic, I; Mise, S; Seiwerth, S; Turkovic, B; Grabarevic, Z; Petek, M; Rucman, R

    2000-01-01

    Up to now, for gastric lesions potentiation or induction, as well as determination of endogenous dopamine significance, dopamine antagonist or dopamine vesicle depletor were given separately. Therefore, without combination studies, the evidence for dopamine significance remains split on either blockade of dopamine post-synaptic receptor or inhibition of dopamine storage, essentially contrasting with endogenous circumstances, where both functions could be simultaneously disturbed. For this purpose, a co-administration of reserpine and haloperidol, a dopamine granule depletor combined with a dopamine antagonist with pronounced ulcerogenic effect, was tested, and the rats were sacrificed 24 h after injurious agent(s) administration. Haloperidol (5 mg x kg(-1) b.w. i.p.), given alone, produced the lesions in all rats. Reserpine (5 mg x kg(-1) b.w. i.p.), given separately, also produced lesions. When these agents were given together, the lesions were apparently larger than in the groups injured with separate administration of either haloperidol or reserpine alone. Along with our previous results, when beneficial agents were co-administered, all dopaminomimetics (bromocriptine 10 mg, apomophine 1 mg, amphetamine 20 mg x kg(-1) i.p.) apparently attenuated the otherwise consistent haloperidol-gastric lesions. Likewise, an apparent inhibition of the reserpine-lesions was noted as well. However, if they were given in rats injured with combination of haloperidol and reserpine, their otherwise prominent beneficial effects were absent. Ranitidine (10 mg), omeprazole (10 mg), atropine (10 mg), pentadecapeptide BPC 157 (Gly-Glu-Pro-Pro-Pro-Gly-Lys-Pro-Ala-Asp-Asp-Ala-Gly-Leu-Val) (10 microg or 10 ng x kg(-1) i.p.) evidently prevented both haloperidol-gastric lesions and reserpine-gastric lesions. Confronted with potentiated lesions following a combination of haloperidol and reserpine, these agents maintained their beneficial effects, noted in the rats treated with either haloperidol or reserpine alone. The failure of dopaminomimetics could be most likely due to more extensive inhibition of endogenous dopamine system activity, and need for remained endogenous dopamine for their salutary effect, whereas the beneficial activities of ranitidine, omeprazole, atropine, pentadecapeptide BPC 157 following dopamine system inhibition by haloperidol+reserpine suggest their corresponding systems parallel those of dopamine system, and they may function despite extensive inhibition of endogenous dopamine system activity. PMID:10791690

  17. Depletion of Tumor-Associated Macrophages Slows the Growth of Chemically Induced Mouse Lung Adenocarcinomas

    PubMed Central

    Fritz, Jason M.; Tennis, Meredith A.; Orlicky, David J.; Yin, Hao; Ju, Cynthia; Redente, Elizabeth F.; Choo, Kevin S.; Staab, Taylor A.; Bouchard, Ronald J.; Merrick, Daniel T.; Malkinson, Alvin M.; Dwyer-Nield, Lori D.

    2014-01-01

    Chronic inflammation is a risk factor for lung cancer, and low-dose aspirin intake reduces lung cancer risk. However, the roles that specific inflammatory cells and their products play in lung carcinogenesis have yet to be fully elucidated. In mice, alveolar macrophage numbers increase as lung tumors progress, and pulmonary macrophage programing changes within 2?weeks of carcinogen exposure. To examine how macrophages specifically affect lung tumor progression, they were depleted in mice bearing urethane-induced lung tumors using clodronate-encapsulated liposomes. Alveolar macrophage populations decreased to ?50% of control levels after 46?weeks of liposomal clodronate treatment. Tumor burden decreased by 50% compared to vehicle treated mice, and tumor cell proliferation, as measured by Ki67 staining, was also attenuated. Pulmonary fluid levels of insulin-like growth factor-I, CXCL1, IL-6, and CCL2 diminished with clodronate liposome treatment. Tumor-associated macrophages expressed markers of both M1 and M2 programing in vehicle and clodronate liposome-treated mice. Mice lacking CCR2 (the receptor for macrophage chemotactic factor CCL2) had comparable numbers of alveolar macrophages and showed no difference in tumor growth rates when compared to similarly treated wild-type mice suggesting that while CCL2 may recruit macrophages to lung tumor microenvironments, redundant pathways can compensate when CCL2/CCR2 signaling is inactivated. Depletion of pulmonary macrophages rather than inhibition of their recruitment may be an advantageous strategy for attenuating lung cancer progression. PMID:25505466

  18. Phagocyte depletion inhibits AA amyloid accumulation in AEF-induced huIL-6 transgenic mice

    PubMed Central

    Kennel, Stephen J.; Macy, Sallie; Wooliver, Craig; Huang, Ying; Richey, Tina; Heidel, Eric; Wall, Jonathan S.

    2014-01-01

    OBJECTIVE Determine the role of phagocytosis in the deposition of acute phase SAA protein in peripheral organs as AA amyloid. METHODS AA amyloidosis was induced by injection of amyloid enhancing factor (AEF) in huIL-6 transgenic mice. Clodronate liposomes were injected at different times, and the amyloid load evaluated by Congo red birefringence staining and monitoring with the amyloid specific probe 125I-labeled peptide p5R. RESULTS Injection of clodronate containing liposomes depleted Iba-1 positive and F4/80 positive phagocytic cells in liver and spleen for up to 5 days. Treatment prior to administration of intravenous AEF did not alter the pattern of deposition of the AEF in spleen, but inhibited the catabolism of the 125I-labeled AEF. Clodronate treatment 1 day before or 1 day after AEF administration had little effect on AA amyloid accumulation at 2 weeks; however, mice treated with clodronate liposomes 5 days after AEF induction and evaluated at 2 weeks post AEF induction showed reduced amyloid load relative to controls. At 6 weeks post-AEF there was no significant effect on amyloid load following a single clodronate treatment. CONCLUSION Macrophages have been shown to be instrumental in both accumulation and clearance of AA amyloid after cessation of inflammation. Our data indicate that when SAA protein is continuously present, depletion of phagocytic cells during the early course of the disease progression temporarily reduces amyloid load. PMID:24446872

  19. Glutathione depletion due to copper-induced phytochelatin synthesis causes oxidative stress in Silene cucubalus

    SciTech Connect

    Ric De Vos, C.H.; Vonk, M.J.; Vooijs, R.; Schat, H. )

    1992-03-01

    The relation between loss of glutathione due to metal-induced phytochelatin synthesis and oxidative stress was studied in the roots of copper-sensitive and tolerant Silene cucubalus (L.) Wib., resistant to 1 and 40 micromolar Cu, respectively. The amount of nonprotein sulfhydryl compounds other then glutathione was taken as a measure of phytochelatins. At a supply of 20 micromolar Cu, which is toxic for sensitive plants only, phytochelatin synthesis and loss of total glutathione were observed only in sensitive plants within 6 h of exposure. When the plants were exposed to a range of copper concentrations for 3 d, a marked production of phytochelatins in sensitive plants was already observed at 0.5 micromolar Cu, whereas the production in tolerant plants was negligible at 40 micromolar or lower. The highest production in tolerant plants was only 40% of that in sensitive plants. In both varieties, the synthesis of phytochelatins was coupled to a loss of glutathione. Copper at toxic concentrations caused oxidative stress, as was evidenced by both the accumulation of lipid peroxidation products and a shift in the glutathione redox couple to a more oxidized state. Depletion of glutathione by pretreatment with buthionine sulfoximine significantly increased the oxidative damage by copper. At a comparably low glutathione level, cadmium had no effect on either lipid peroxidation or the glutathione redox couple in buthionine sulfoximine-treated plants. These results indicate that copper may specifically cause oxidative stress by depletion of the antioxidant glutathione due to phytochelatin synthesis.

  20. The membrane-raft protein Flotillin-1 is essential in dopamine neurons for amphetamine-induced behavior in Drosophila

    PubMed Central

    Pizzo, Andrea B.; Karam, Caline S.; Zhang, Yuchao; Yano, Hideaki; Freyberg, Robin J.; Karam, David S.; Freyberg, Zachary; Yamamoto, Ai; McCabe, Brian D.; Javitch, Jonathan A.

    2012-01-01

    The dopamine transporter (DAT) is the primary molecular target responsible for the rewarding properties of the psychostimulants amphetamine (AMPH) and cocaine. AMPH increases extracellular dopamine (DA) by promoting its nonexocytotic release via DAT-mediated efflux. Previous studies in heterologous cells have shown that phosphorylation of the amino terminus of DAT is required for AMPH-induced DA efflux but not for DA uptake. However, the identity of many of the modulatory proteins and the molecular mechanisms that coordinate efflux and the ensuing behavioral effects remain poorly defined. Here we establish a robust assay for AMPH-induced hyperlocomotion in Drosophila melanogaster larvae. Using a variety of genetic and pharmacological approaches we demonstrate that this behavioral response is dependent on DA and on DAT and its phosphorylation. We also show that methylphenidate (MPH), which competitively inhibits DA uptake but does not induce DAT-mediated DA efflux, also leads to DAT-dependent hyperlocomotion, but this response is independent of DAT phosphorylation. Moreover, we demonstrate that the membrane raft protein Flotillin1 is required for AMPH-induced but not MPH-induced hyperlocomotion. These results are the first evidence of a role for a raft protein in an AMPH-mediated behavior. Thus, using our assay we are able to translate molecular and cellular findings to a behavioral level and to differentiate in vivo the distinct mechanisms of two psychostimulants. PMID:22710269

  1. Speech-induced striatal dopamine release is left lateralized and coupled to functional striatal circuits in healthy humans: A combined PET, fMRI and DTI study

    PubMed Central

    Simonyan, Kristina; Herscovitch, Peter; Horwitz, Barry

    2013-01-01

    Considerable progress has been recently made in understanding the brain mechanisms underlying speech and language control. However, the neurochemical underpinnings of normal speech production remain largely unknown. We investigated the extent of striatal endogenous dopamine release and its influences on the organization of functional striatal speech networks during production of meaningful English sentences using a combination of positron emission tomography (PET) with the dopamine D2/D3 receptor radioligand [11C]raclopride and functional MRI (fMRI). In addition, we used diffusion tensor tractography (DTI) to examine the extent of dopaminergic modulatory influences on striatal structural network organization. We found that, during sentence production, endogenous dopamine was released in the ventromedial portion of the dorsal striatum, in its both associative and sensorimotor functional divisions. In the associative striatum, speech-induced dopamine release established a significant relationship with neural activity and influenced the left-hemispheric lateralization of striatal functional networks. In contrast, there were no significant effects of endogenous dopamine release on the lateralization of striatal structural networks. Our data provide the first evidence for endogenous dopamine release in the dorsal striatum during normal speaking and point to the possible mechanisms behind the modulatory influences of dopamine on the organization of functional brain circuits controlling normal human speech. PMID:23277111

  2. D-2 dopamine receptor activation reduces free ( sup 3 H)arachidonate release induced by hypophysiotropic peptides in anterior pituitary cells

    SciTech Connect

    Canonico, P.L. )

    1989-09-01

    Dopamine reduces the stimulation of intracellular ({sup 3}H)arachidonate release produced by the two PRL-stimulating peptides angiotensin-II and TRH. This effect is concentration dependent and is mediated by stimulation of D-2 dopamine receptors. D-2 receptor agonists (bromocriptine, dihydroergocryptine, and dihydroergocristine) inhibit the release of fatty acid induced by angiotensin-II with a potency that parallels their ability to inhibit PRL release in vitro. Conversely, the selective D-2 receptor antagonist L-sulpiride completely prevents dopamine's effect, whereas SCH 23390 (a D-1 receptor antagonist) is ineffective. The inhibitory action of dopamine does not seem to be consequent to an action on the adenylate cyclase-cAMP system, as 8-bromo-cAMP (1 mM) does not affect either basal or dopamine-inhibited ({sup 3}H)arachidonate release. However, a 24-h pertussis toxin pretreatment significantly reduces the action of dopamine on fatty acid release. Collectively, these results suggest that D-2 dopamine receptor-mediated inhibition of intracellular ({sup 3}H)arachidonate release requires the action of a GTP-binding protein, but is not a consequence of an inhibitory action on cAMP levels.

  3. Acute dyskerin depletion triggers cellular senescence and renders osteosarcoma cells resistant to genotoxic stress-induced apoptosis

    SciTech Connect

    Lin, Ping; Mobasher, Maral E.; Alawi, Faizan

    2014-04-18

    Highlights: • Dyskerin depletion triggers cellular senescence in U2OS osteosarcoma cells. • Dyskerin-depleted cells are resistant to apoptosis induced by genotoxic stress. • Chromatin relaxation sensitizes dyskerin-depleted cells to apoptosis. - Abstract: Dyskerin is a conserved, nucleolar RNA-binding protein implicated in an increasing array of fundamental cellular processes. Germline mutation in the dyskerin gene (DKC1) is the cause of X-linked dyskeratosis congenita (DC). Conversely, wild-type dyskerin is overexpressed in sporadic cancers, and high-levels may be associated with poor prognosis. It was previously reported that acute loss of dyskerin function via siRNA-mediated depletion slowed the proliferation of transformed cell lines. However, the mechanisms remained unclear. Using human U2OS osteosarcoma cells, we show that siRNA-mediated dyskerin depletion induced cellular senescence as evidenced by proliferative arrest, senescence-associated heterochromatinization and a senescence-associated molecular profile. Senescence can render cells resistant to apoptosis. Conversely, chromatin relaxation can reverse the repressive effects of senescence-associated heterochromatinization on apoptosis. To this end, genotoxic stress-induced apoptosis was suppressed in dyskerin-depleted cells. In contrast, agents that induce chromatin relaxation, including histone deacetylase inhibitors and the DNA intercalator chloroquine, sensitized dyskerin-depleted cells to apoptosis. Dyskerin is a core component of the telomerase complex and plays an important role in telomere homeostasis. Defective telomere maintenance resulting in premature senescence is thought to primarily underlie the pathogenesis of X-linked DC. Since U2OS cells are telomerase-negative, this leads us to conclude that loss of dyskerin function can also induce cellular senescence via mechanisms independent of telomere shortening.

  4. The thyrotrophin-releasing hormone analogue MK771 induces tic-like behaviours: the effects of dopamine D1 and D2 receptor antagonists.

    PubMed

    McCreary, A C; Handley, S L

    1999-03-12

    Thyrotrophin-releasing hormone (TRH) and its analogues induce tic-like behaviours in rodents such as blinking and forepaw licking. Changes in spontaneous blinking frequency are observed in several disease states with dopamine abnormalities and dopaminergic agents modulate blinking. We have therefore investigated the effects of dopamine D1 and D2 receptor antagonists on TRH analogue (1-pyro-2-aminoadipyl-L-histidyl-L-thiazolidine-4-carboxamide; MK771)-induced blinking and bouts of forepaw licking. MK771 (2.5 mg/kg)-induced blinking was not attenuated by the dopamine D1 receptor antagonists (+)-7-chloro-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro(1H)-3-benzazep ine maleate (SCH23390) (0.01, 1.0 and 5.0 mg/kg) and ((-)-trans-6,7,7a,8,9,13b-hexahydro-3-chloro-2-hydroxy-N-methyl-5- H-benz[2,1b]azepine (SCH39166; 1.0 and 5.0 mg/kg) or the dopamine D2 receptor antagonists raclopride (3.0 and 5.0 mg/kg) and sulpiride (5.0 and 10.0 mg/kg). D1 but not D2 receptor antagonists attenuated MK771-induced forepaw licking. MK771-induced blinking, therefore, appears not to involve dopamine D1 or D2 receptors and contrary to previously held belief dopamine does not appear to be pivotal in the control of blinking, while MK771-induced forepaw licking is modulated by dopamine D1 but not D2 receptors. PMID:10204674

  5. Aggregate-depleted brain fails to induce Aβ deposition in a mouse model of Alzheimer's disease.

    PubMed

    Duran-Aniotz, Claudia; Morales, Rodrigo; Moreno-Gonzalez, Ines; Hu, Ping Ping; Fedynyshyn, Joseph; Soto, Claudio

    2014-01-01

    Recent studies in animal models of Alzheimer's disease (AD) show that amyloid-beta (Aβ) misfolding can be transmissible; however, the mechanisms by which this process occurs have not been fully explored. The goal of this study was to analyze whether depletion of aggregates from an AD brain suppresses its in vivo "seeding" capability. Removal of aggregates was performed by using the Aggregate Specific Reagent 1 (ASR1) compound which has been previously described to specifically bind misfolded species. Our results show that pre-treatment with ASR1-coupled magnetic beads reduces the in vivo misfolding inducing capability of an AD brain extract. These findings shed light respect to the active principle responsible for the prion-like spreading of Alzheimer's amyloid pathology and open the possibility of using seeds-capturing reagents as a promising target for AD treatment. PMID:24533166

  6. Micelle depletion-induced vs. micelle-mediated aggregation in nanoparticles

    NASA Astrophysics Data System (ADS)

    Ray, D.; Aswal, V. K.

    2015-06-01

    The phase behavior anionic silica nanoparticle (Ludox LS30) with non-ionic surfactants decaethylene glycol monododecylether (C12E10) and cationic dodecyltrimethyl ammonium bromide (DTAB) in aqueous electrolyte solution has been studied by small-angle neutron scattering (SANS). The measurements have been carried out for fixed concentrations of nanoparticle (1 wt%), surfactants (1 wt%) and electrolyte (0.1 M NaCl). Each of these nanoparticle-surfactant systems has been examined for different contrast conditions where individual components (nanoparticle or surfactant) are made visible. It is observed that the nanoparticle-micelle system in both the cases lead to the aggregation of nanoparticles. The aggregation is found to be micelle depletion-induced for C12E10 whereas micelle-mediated aggregation for DTAB. Interestingly, it is also found that phase behavior of mixed surfactant (C12E10 + DTAB) system is similar to that of C12E10 (unlike DTAB) micelles with nanoparticles.

  7. Gastrin and D1 dopamine receptor interact to induce natriuresis and diuresis.

    PubMed

    Chen, Yue; Asico, Laureano D; Zheng, Shuo; Villar, Van Anthony M; He, Duofen; Zhou, Lin; Zeng, Chunyu; Jose, Pedro A

    2013-11-01

    Oral NaCl produces a greater natriuresis and diuresis than the intravenous infusion of the same amount of NaCl. Gastrin is the major gastrointestinal hormone taken up by renal proximal tubule (RPT) cells. We hypothesized that renal gastrin and dopamine receptors interact to synergistically increase sodium excretion, an impaired interaction of which may be involved in the pathogenesis of hypertension. In Wistar-Kyoto rats, infusion of gastrin induced natriuresis and diuresis, which was abrogated in the presence of a gastrin (cholecystokinin B receptor [CCKBR]; CI-988) or a D1-like receptor antagonist (SCH23390). Similarly, the natriuretic and diuretic effects of fenoldopam, a D1-like receptor agonist, were blocked by SCH23390, as well as by CI-988. However, the natriuretic effects of gastrin and fenoldopam were not observed in spontaneously hypertensive rats. The gastrin/D1-like receptor interaction was also confirmed in RPT cells. In RPT cells from Wistar-Kyoto but not spontaneously hypertensive rats, stimulation of either D1-like receptor or gastrin receptor inhibited Na(+)-K(+)-ATPase activity, an effect that was blocked in the presence of SCH23390 or CI-988. In RPT cells from Wistar-Kyoto and spontaneously hypertensive rats, CCKBR and D1 receptor coimmunoprecipitated, which was increased after stimulation of either D1 receptor or CCKBR in RPT cells from Wistar-Kyoto rats; stimulation of one receptor increased the RPT cell membrane expression of the other receptor, effects that were not observed in spontaneously hypertensive rats. These data suggest that there is a synergism between CCKBR and D1-like receptors to increase sodium excretion. An aberrant interaction between the renal CCK?BR and D1-like receptors (eg, D1 receptor) may play a role in the pathogenesis of hypertension. PMID:24019399

  8. Variants of the dopamine D2 receptor and risperidone-induced hyperprolactinemia in children and adolescents

    PubMed Central

    Calarge, Chadi A.; Ellingrod, Vicki L.; Acion, Laura; Miller, Del D.; Moline, Jessica; Tansey, Michael J.; Schlechte, Janet A.

    2009-01-01

    Objective To investigate the association between hyperprolactinemia and variants of the dopamine D2 receptor (DRD2) gene in children and adolescents in long-term treatment with risperidone. Methods Medically healthy 717-year-old patients chronically treated with risperidone but receiving no other antipsychotics were selected for a cross-sectional evaluation. Four DRD2 variants were genotyped and prolactin concentration was measured. Medication history was obtained from the medical record. The effect of the TaqIA variants of the DRD2 on the risk of risperidone-induced hyperprolactinemia was the primary outcome measure. Results Hyperprolactinemia was present in 50% of 107 patients (87% males) treated with risperidone for an average of 2.9 years. Age, stage of sexual development, and the dose of risperidone independently predicted a higher prolactin concentration, whereas the dose of psychostimulants was negatively correlated with it. However, these four predictors became nonsignificant when risperidone serum concentration was entered into the model. Adverse events potentially related to hyperprolactinemia were more common in participants with elevated prolactin concentration in girls (45%) compared with boys (10%). After controlling for risperidone concentration and the dose of psychostimulants, the TaqIA A1 and the A-241G alleles were associated with higher prolactin concentration, whereas the -141C Ins/Del AQ1and C957T variants had no significant effect. In addition, adverse events potentially related to hyperprolactinemia were four times more common in TaqIA A1 allele carriers. Conclusion Prolactin concentration is closely related to central DRD2 blockade, as reflected by risperidone serum concentration. Furthermore, the TaqIA and A-241G variants of the DRD2 gene could be useful in predicting the emergence of hyperprolactinemia and its potential adverse events. PMID:19339912

  9. Measuring cigarette smoking-induced cortical dopamine release: A [C]FLB-457 PET study.

    PubMed

    Wing, Victoria C; Payer, Doris E; Houle, Sylvain; George, Tony P; Boileau, Isabelle

    2015-05-01

    Striatal dopamine (DA) is thought to have a fundamental role in the reinforcing effects of tobacco smoking and nicotine. Microdialysis studies indicate that nicotine also increases DA in extrastriatal brain areas, but much less is known about its role in addiction. High-affinity D2/3 receptor radiotracers permit the measurement of cortical DA in humans using positron emission tomography (PET). [(11)C]FLB-457 PET scans were conducted in 10 nicotine-dependent daily smokers after overnight abstinence and reinstatement of smoking. Voxel-wise [(11)C]-FLB-457-binding potential (BPND) in the frontal lobe, insula, and limbic regions was estimated in the two conditions. Paired t-tests showed BPND values were reduced following smoking (an indirect index of DA release). The overall peak t was located in the cingulate gyrus, which was part of a larger medial cluster (BPND change -12.19.4%) and this survived false discovery rate correction for multiple comparisons. Clusters were also identified in the left anterior cingulate cortex/medial frontal gyrus, bilateral prefrontal cortex (PFC), bilateral amygdala, and the left insula. This is the first demonstration of tobacco smoking-induced cortical DA release in humans; it may be the result of both pharmacological (nicotine) and non-pharmacological factors (tobacco cues). Abstinence increased craving but had minimal cognitive effects, thus limiting correlation analyses. However, given that the cingulate cortex, PFC, insula, and amygdala are thought to have important roles in tobacco craving, cognition, and relapse, these associations warrant investigation in a larger sample. [(11)C]FLB-457 PET imaging may represent a useful tool to investigate individual differences in tobacco addiction severity and treatment response. PMID:25502631

  10. THE METAL TRANSPORTER SMF-3/DMT-1 MEDIATES ALUMINUM-INDUCED DOPAMINE NEURON DEGENERATION

    PubMed Central

    VanDuyn, Natalia; Settivari, Raja; LeVora, Jennifer; Zhou, Shaoyu; Unrine, Jason; Nass, Richard

    2012-01-01

    Aluminum (Al3+) is the most prevalent metal in the earth's crust, and is a known human neurotoxicant. Al3+ has been shown to accumulate in the substantia nigra of Parkinson's disease (PD) patients, and epidemiological studies suggest correlations between Al3+ exposure and the propensity to develop both PD and the amyloid plaque-associated disorder Alzheimer's disease (AD). Although Al3+ exposures have been associated with the development of the most common neurodegenerative disorders, the molecular mechanism involved in Al3+ transport in neurons and subsequent cellular death has remained elusive. In this study we show that a brief exposure to Al3+ decreases mitochondrial membrane potential and cellular ATP levels, and confers dopamine (DA) neuron degeneration in the genetically tractable nematode Caenorhabditis elegans (C. elegans). Al3+ exposure also exacerbates DA neuronal death conferred by the human PD-associated protein ?-synuclein. DA neurodegeneration is dependent on SMF-3, a homologue to the human divalent metal transporter (DMT-1), as a functional null mutation partially inhibits the cell death. We also show that SMF-3 is expressed in DA neurons, Al3+ exposure results in a significant decrease in protein levels, and the neurodegeneration is partially dependent on the PD-associated transcription factor Nrf2/SKN-1 and caspase Apaf1/CED-4. Furthermore we provide evidence that the deletion of SMF-3 confers Al3+-resistance due to sequestration of Al3+ into an intracellular compartment. This study describes a novel model for Al3+-induced DA neurodegeneration and provides the first molecular evidence of an animal Al3+ transporter. PMID:23106139

  11. Agonist-induced morphologic decrease in cellular D1A dopamine receptor staining.

    PubMed

    Ariano, M A; Sortwell, C E; Ray, M; Altemus, K L; Sibley, D R; Levine, M S

    1997-12-01

    The distribution of D1A dopamine (DA) receptor proteins was assessed by using subtype specific antireceptor antisera after acute DA exposure. The immunofluorescent staining of D1A DA receptor protein expression was examined in (1) stably transfected Chinese hamster ovary (CHO) cells, (2) primary striatal cell cultures, and (3) rat striatal brain slices. After agonist exposure as brief as 2 min and as long as 60 min, profound loss of immunofluorescent D1A receptor protein staining occurred in each paradigm. Additionally in the tissue slice, immunofluorescent neuropil staining for the receptor protein also was attenuated. The DA-induced alteration in receptor protein staining was blocked by the antagonist (+)-butaclamol and by the selective D1-family antagonist SCH 23390. Receptor staining patterns reverted back to the control immunofluorescent distribution within 15 min after removing the agonist from the bath. Immunofluorescence for the second-messenger cyclic AMP increased at all DA exposure times in the three experimental paradigms, was blocked by D1-family antagonists, and decreased to basal staining after brief recovery periods. This demonstrated the functional integrity of the D1A receptor in target cells. Pretreatment with the mitogenic plant lectin concanavalin A blocked the immunofluorescent decrease in receptor staining but not the elevation of the second messenger, indicating a morphologic distinction in these two events, parallel to other biochemical reports. The data suggested that a morphologic basis of acute homologous D1A DA receptor desensitization may be transposition of membrane-surface receptors to a transiently unavailable, intracellular compartment. This finding is supported by specific fluorescence incorporation of FM1-43, used as a marker of endocytosis, in CHO cells treated with DA. PMID:9372554

  12. Risk-assessment and risk-taking behavior predict potassium- and amphetamine-induced dopamine response in the dorsal striatum of rats

    PubMed Central

    Palm, Sara; Momeni, Shima; Lundberg, Stina; Nylander, Ingrid; Roman, Erika

    2014-01-01

    Certain personality types and behavioral traits display high correlations to drug use and an increased level of dopamine in the reward system is a common denominator of all drugs of abuse. Dopamine response to drugs has been suggested to correlate with some of these personality types and to be a key factor influencing the predisposition to addiction. This study investigated if behavioral traits can be related to potassium- and amphetamine-induced dopamine response in the dorsal striatum, an area hypothesized to be involved in the shift from drug use to addiction. The open field and multivariate concentric square field tests were used to assess individual behavior in male Wistar rats. Chronoamperometric recordings were then made to study the potassium- and amphetamine-induced dopamine response in vivo. A classification based on risk-taking behavior in the open field was used for further comparisons. Risk-taking behavior was correlated between the behavioral tests and high risk takers displayed a more pronounced response to the dopamine uptake blocking effects of amphetamine. Behavioral parameters from both tests could also predict potassium- and amphetamine-induced dopamine responses showing a correlation between neurochemistry and behavior in risk-assessment and risk-taking parameters. In conclusion, the high risk-taking rats showed a more pronounced reduction of dopamine uptake in the dorsal striatum after amphetamine indicating that this area may contribute to the sensitivity of these animals to psychostimulants and proneness to addiction. Further, inherent dopamine activity was related to risk-assessment behavior, which may be of importance for decision-making and inhibitory control, key components in addiction. PMID:25076877

  13. LINE-1 hypomethylation induced by reactive oxygen species is mediated via depletion of S-adenosylmethionine.

    PubMed

    Kloypan, Chiraphat; Srisa-art, Monpicha; Mutirangura, Apiwat; Boonla, Chanchai

    2015-08-01

    Whether long interspersed nuclear element-1 (LINE-1) hypomethylation induced by reactive oxygen species (ROS) was mediated through the depletion of S-adenosylmethionine (SAM) was investigated. Bladder cancer (UM-UC-3 and TCCSUP) and human kidney (HK-2) cell lines were exposed to 20 μM H2O2 for 72 h to induce oxidative stress. Level of LINE-1 methylation, SAM and homocysteine (Hcy) was measured in the H2O2 -exposed cells. Effects of α-tocopheryl acetate (TA), N-acetylcysteine (NAC), methionine, SAM and folic acid on oxidative stress and LINE-1 methylation in the H2O2 -treated cells were explored. Viabilities of cells treated with H2O2 were not significantly changed. Intracellular ROS production and protein carbonyl content were significantly increased, but LINE-1 methylation was significantly decreased in the H2O2 -treated cells. LINE-1 methylation was restored by TA, NAC, methionine, SAM and folic acid. SAM level in H2O2 -treated cells was significantly decreased, while total glutathione was significantly increased. SAM level in H2O2 -treated cells was restored by NAC, methionine, SAM and folic acid; while, total glutathione level was normalized by TA and NAC. Hcy was significantly decreased in the H2O2 -treated cells and subsequently restored by NAC. In conclusion, in bladder cancer and normal kidney cells exposed to H2O2 , SAM and Hcy were decreased, but total glutathione was increased. Treatments with antioxidants (TA and NAC) and one-carbon metabolites (SAM, methionine and folic acid) restored these changes. This pioneer finding suggests that exposure of cells to ROS activates glutathione synthesis via the transsulfuration pathway leading to deficiency of Hcy, which consequently causes SAM depletion and eventual hypomethylation of LINE-1. PMID:26178977

  14. Depletion-induced forces and crowding in polymer-nanoparticle mixtures: Role of polymer shape fluctuations and penetrability.

    PubMed

    Lim, Wei Kang; Denton, Alan R

    2016-01-14

    Depletion forces and macromolecular crowding govern the structure and function of biopolymers in biological cells and the properties of polymer nanocomposite materials. To isolate and analyze the influence of polymer shape fluctuations and penetrability on depletion-induced interactions and crowding by nanoparticles, we model polymers as effective penetrable ellipsoids, whose shapes fluctuate according to the probability distributions of the eigenvalues of the gyration tensor of an ideal random walk. Within this model, we apply Monte Carlo simulation methods to compute the depletion-induced potential of mean force between hard nanospheres and crowding-induced shape distributions of polymers in the protein limit, in which polymer coils can be easily penetrated by smaller nanospheres. By comparing depletion potentials from simulations of ellipsoidal and spherical polymer models with predictions of polymer field theory and free-volume theory, we show that polymer depletion-induced interactions and crowding depend sensitively on polymer shapes and penetrability, with important implications for bulk thermodynamic phase behavior. PMID:26772587

  15. Cofilin phosphorylation is elevated after F-actin disassembly induced by Rac1 depletion.

    PubMed

    Liu, Linna; Li, Jing; Zhang, Liwang; Zhang, Feng; Zhang, Rong; Chen, Xiang; Brakebusch, Cord; Wang, Zhipeng; Liu, Xinyou

    2015-01-01

    Cytoskeletal reorganization is essential to keratinocyte function. Rac1 regulates cytoskeletal reorganization through signaling pathways such as the cofilin cascade. Cofilin severs actin filaments after activation by dephosphorylation. Rac1 was knocked out in mouse keratinocytes and it was found that actin filaments disassembled. In the epidermis of mice in which Rac1 was knocked out only in keratinocytes, cofilin phosphorylation was aberrantly elevated, corresponding to repression of the phosphatase slingshot1 (SSH1). These effects were independent of the signaling pathways for p21-activated kinase/LIM kinase (Pak/LIMK), protein kinase C, or protein kinase D or generation of reactive oxygen species. Similarly, when actin polymerization was specifically inhibited or Rac1 was knocked down, cofilin phosphorylation was enhanced and SSH1 was repressed. Repression of SSH1 partially blocked actin depolymerization induced by Rac1 depletion. Therefore, aberrant cofilin phosphorylation that induces actin polymerization might be a consequence of actin disassembly induced by the absence of Rac1. PMID:26496994

  16. Effects of 18-methoxycoronaridine on ghrelin-induced increases in sucrose intake and accumbal dopamine overflow in female rats

    PubMed Central

    Taraschenko, Olga D.; Hathaway, Ethan R.; Vincent, Melanie Y.; Glick, Stanley D.

    2013-01-01

    Rationale 18-Methoxycoronaridine (18-MC), a selective antagonist of ?3?4 nicotinic receptors, has been previously shown, in rats, to reduce the self-administration of several drugs of abuse, reduce operant responding for sucrose, and prevent the development of sucrose-induced obesity. It has become increasingly apparent that there is a significant overlap between the systems regulating drug reward and food intake, therefore, we investigated whether 18-MC might modulate the effects of ghrelin, one of several orexigenic peptides recently implicated in both feeding and drug reward. Objectives In female SpragueDawley rats, we determined whether acute 18-MC treatment would reduce both ghrelin-induced increases in sucrose intake and ghrelin-elicited increases in accumbal dopamine levels. Results Pretreatment with 18-MC (20 mg/kg, i.p.), given prior to the administration of ghrelin (1 g, lateral ventricle), blocked ghrelin-induced increases in sucrose (5%) intake in a two-bottle open access paradigm. Using in vivo microdialysis, 18-MC (both 20 and 40 mg/kg) prevented ghrelin (2 g, intraventral tegmental area)-induced increases in extracellular dopamine in the nucleus accumbens. 18-MC had no effect on deposition of fat or on serum levels of glucose, triglycerides, and cholesterol in ghrelin-treated rats. Conclusions The present results suggest that one potential mechanism by which 18-MC exerts its effects on palatable food consumption is via modulation of ghrelins effects. PMID:21210086

  17. Altered sensitivity to d-methylamphetamine, apomorphine, and haloperidol in rhesus monkeys depleted of caudate dopamine by repeated administration of d-methylamphetamine.

    PubMed

    Finnegan, K T; Ricaurte, G; Seiden, L S; Schuster, C R

    1982-01-01

    The long-term neurochemical and behavioral effects of repeated d-methylamphetamine (d-MA) administration were investigated using four male rhesus monkeys trained to lever-press for food on a DRL-40s schedule of reinforcement. Dose-response curves for d-MA (0.0625-2.0 mg/kg), apomorphine (0.025-0.4 mg/kg), and haloperidol (0.005-0.04 mg/kg) on responding showed that repeated d-MA administration (0.5-16.0 mg/kg/day) decreased sensitivity to d-MA and to apomorphine but increased sensitivity to haloperidol. At 3-6 months after the last injection of d-MA, a 48.1% decrease in caudate dopamine (DA) was observed, with the frontal cortex, midbrain, and pons-medulla showing no significant change. A trend toward increasing concentrations of norepinephrine was noted in the same brain areas, but only in the frontal cortex did this change reach significance. Specific binding of 3H-spiroperidol to caudate membrane preparations was not changed, while the Vmax of the caudate DA re-uptake process declined 32%, with no change in Km. These results suggest that exposure of DA neurons in the caudate nucleus to high concentrations of d-MA can lead to nerve terminal degeneration. PMID:6812118

  18. The Role of Dopamine in Reinforcement: Changes in Reinforcement Sensitivity Induced by D1-type, D2-type, and Nonselective Dopamine Receptor Agonists

    PubMed Central

    Bratcher, Natalie A; Farmer-Dougan, Valeri; Dougan, James D; Heidenreich, Byron A; Garris, Paul A

    2005-01-01

    Dose-dependent changes in sensitivity to reinforcement were found when rats were treated with low, moderate, and high doses of the partial dopamine D1-type receptor agonist SKF38393 and with the nonselective dopamine agonist apomorphine, but did not change when rats were treated with similar doses of the selective dopamine D2-type receptor agonist quinpirole. Estimates of bias did not differ significantly across exposure to SKF38393 or quinpirole, but did change significantly at the high dose of apomorphine. Estimates of goodness of fit (r2) did not change significantly during quinpirole exposure. Poor goodness of fit was obtained for the high doses of SKF38393 and apomorphine. Decrements in absolute rates of responding were observed at the high dose of quinpirole and at the moderate and high doses of SKF38393 and apomorphine. Changes in r2 and absolute responding may be due to increases in stereotyped behavior during SKF38393 and apomorphine exposure that, in contrast to quinpirole, were distant from the response lever. The present data provide evidence that sensitivity to reward is affected more strongly by dopamine D1-like receptors rather than D2-like receptors, consistent with evidence from other studies investigating consummatory dopamine behavior and the tonic/phasic dopamine hypothesis. PMID:16596971

  19. Mutations at Tyrosine 88, Lysine 92 and Tyrosine 470 of human dopamine transporter result in an attenuation of HIV-1 Tat-induced inhibition of dopamine transport

    PubMed Central

    Midde, Narasimha M.; Yuan, Yaxia; Quizon, Pamela M.; Sun, Wei-Lun; Huang, Xiaoqin; Zhan, Chang-Guo; Zhu, Jun

    2015-01-01

    HIV-1 transactivator of transcription (Tat) protein disrupts the dopamine (DA) neurotransmission by inhibiting DA transporter (DAT) function, leading to increased neurocognitive impairment in HIV-1 infected individuals. Through integrated computational modeling and pharmacological studies, we have demonstrated that mutation of tyrosine470 (Y470H) of human DAT (hDAT) attenuates Tat-induced inhibition of DA uptake by changing the transporter conformational transitions. The present study examined the functional influences of other substitutions at tyrosine470 (Y470F and Y470A) and tyrosine88 (Y88F) and lysine92 (K92M), two other relevant residues for Tat binding to hDAT, in Tat-induced inhibitory effects on DA transport. Y88F, K92M and Y470A attenuated Tat-induced inhibition of DA transport, implicating the functional relevance of these residues for Tat binding to hDAT. Compared to wild type hDAT, Y470A and K92M but not Y88F reduced the maximal velocity of [3H]DA uptake without changes in the Km. Y88F and K92M enhanced IC50 values for DA inhibition of [3H]DA uptake and [3H]WIN35,428 binding but decreased IC50 for cocaine and GBR12909 inhibition of [3H]DA uptake, suggesting that these residues are critical for substrate and these inhibitors. Y470F, Y470A, Y88F and K92M attenuated zinc-induced increase of [3H]WIN35,428 binding. Moreover, only Y470A and K92M enhanced DA efflux relative to wild type hDAT, suggesting mutations of these residues differentially modulate transporter conformational transitions. These results demonstrate Tyr88 and Lys92 along with Tyr470 as functional recognition residues in hDAT for Tat-induced inhibition of DA transport and provide mechanistic insights into identifying target residues on the DAT for Tat binding. PMID:25604666

  20. Coronin 1A depletion protects endothelial cells from TNF?-induced apoptosis by modulating p38? expression and activation.

    PubMed

    Kim, Geun-Young; Kim, Hanna; Lim, Hyun-Joung; Park, Hyun-Young

    2015-09-01

    Coronins are conserved actin-binding proteins that regulate various cellular processes such as migration and endocytosis. Among coronin family members, coronin 1A is highly expressed in hematopoietic lineage cells where it regulates cell homeostasis. However, the expression and function of coronin 1A in endothelial cells have not yet been elucidated. We found that coronin 1A is expressed in the human umbilical vein endothelial cell (HUVEC) and human brain microvascular endothelial cell (HBMVEC). In HUVEC depleted of coronin 1A by siRNA transfection, tumor necrosis factor ? (TNF?)+cyclohexamide (CHX) treatment resulted in a decrease in the number of terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) positive apoptotic cells. Coronin 1A depletion also resulted in the suppression of caspase 3 and poly(ADP-ribose) polymerase cleavage and a reduction in caspase 3 activity. Next, we examined TNF?-induced activation of several pro- and anti-apoptotic signaling molecules to find the target molecule of coronin 1A and found that p38 phosphorylation was enhanced by TNF? stimulation in coronin 1A-depleted HUVEC. Among the p38 isoforms, the expression of p38? was significantly upregulated after coronin 1A depletion, suggesting that the expression and phosphorylation of anti-apoptotic p38? were significantly induced in coronin 1A-depleted HUVEC. Inhibition of p38? upregulation in coronin 1A-depleted HUVEC restored the cleavage of caspase 8 and caspase 3 and induced more apoptosis than in coronin 1A-depleted HUVEC in response to TNF?+CHX. These findings suggest that coronin 1A modulates endothelial cell apoptosis by regulating p38? expression and activation. PMID:25936522

  1. Human Neural Stem Cells Survive Long Term in the Midbrain of Dopamine-Depleted Monkeys After GDNF Overexpression and Project Neurites Toward an Appropriate Target

    PubMed Central

    Wakeman, Dustin R.; Dodiya, Hemraj B.; Sladek, John R.; Leranth, Csaba; Teng, Yang D.; Samulski, R. Jude

    2014-01-01

    Transplanted multipotent human fetal neural stem cells (hfNSCs) significantly improved the function of parkinsonian monkeys in a prior study primarily by neuroprotection, with only 3%5% of cells expressing a dopamine (DA) phenotype. In this paper, we sought to determine whether further manipulation of the neural microenvironment by overexpression of a developmentally critical molecule, glial cell-derived neurotrophic factor (GDNF), in the host striatum could enhance DA differentiation of hfNSCs injected into the substantia nigra and elicit growth of their axons to the GDNF-expressing target. hfNSCs were transplanted into the midbrain of 10 green monkeys exposed to 1-methyl-4-phenyl-1,2,3,6-tetrahydro-pyridine. GDNF was delivered concomitantly to the striatum via an adeno-associated virus serotype 5 vector, and the fate of grafted cells was assessed after 11 months. Donor cells remained predominantly within the midbrain at the injection site and sprouted numerous neurofilament-immunoreactive fibers that appeared to course rostrally toward the striatum in parallel with tyrosine hydroxylase-immunoreactive fibers from the host substantia nigra but did not mature into DA neurons. This work suggests that hfNSCs can generate neurons that project long fibers in the adult primate brain. However, in the absence of region-specific signals and despite GDNF overexpression, hfNSCs did not differentiate into mature DA neurons in large numbers. It is encouraging, however, that the adult primate brain appeared to retain axonal guidance cues. We believe that transplantation of stem cells, specifically instructed ex vivo to yield DA neurons, could lead to reconstruction of some portion of the nigrostriatal pathway and prove beneficial for the parkinsonian condition. PMID:24744393

  2. Exercise-induced heart mitochondrial cholesterol depletion influences the inhibition of mitochondrial swelling.

    PubMed

    Ziolkowski, Wieslaw; Vadhana M S, Dhivya; Kaczor, Jan Jacek; Olek, Robert Antoni; Flis, Damian Jozef; Halon, Malgorzata; Wozniak, Michal; Fedeli, Donatella; Carloni, Manuel; Antosiewicz, Jedrzej; Gabbianelli, Rosita

    2013-10-01

    The significance of the reduction of the cholesterol pool in heart mitochondria after exercise is still unknown. Recently, published data have suggested that cholesterol may influence the components of mitochondrial contact site and affect mitochondrial swelling. Therefore, the aim of this study was to determine whether the decreased cholesterol content in heart mitochondria caused by prolonged swimming may provoke changes in their bioenergetics and result in an increased resistance to calcium chloride-induced mitochondrial swelling. Male Wistar rats were divided into a sedentary control group and an exercise group. The rats exercised for 3 h, burdened with an additional 3% of their body weight. Their hearts were removed immediately after completing the exercise. The left ventricle was divided and used for experiments. Mitochondrial cholesterol content, membrane fluidity and mitochondrial bioenergetics were measured in the control and exercised rat heart mitochondria. To assess whether mitochondrial modifications are linked to disruption of lipid microdomains, methyl-β-cyclodextrin, a well-known lipid microdomain-disrupting agent and cholesterol chelator, was applied to the mitochondria of the control group. Cholesterol depletion, increased membrane fluidity and increased resistance to calcium chloride-induced swelling were observed in postexercise heart crude mitochondrial fraction. Similar results were achieved in control mitochondria treated with 2% methyl-β-cyclodextrin. All of the mitochondrial bioenergetics parameters were similar between the groups. Therefore, the disruption of raft-like microdomains appears to be an adaptive change in the rat heart following exercise. PMID:23733522

  3. Delta-tocotrienol induces apoptotic cell death via depletion of intracellular squalene in ED40515 cells.

    PubMed

    Yamasaki, Masao; Nishimura, Misato; Sakakibara, Yoichi; Suiko, Masahito; Morishita, Kazuhiro; Nishiyama, Kazuo

    2014-11-01

    Here, we examined the effect of tocotrienols (T3) on the growth of adult T-cell leukemia (ATL) cells. All three forms (?-, ?-, and ?-T3) inhibited cell proliferation in a dose-dependent manner; ?-T3 showed the strongest growth-inhibitory effect. ?-T3 increased the G1, G2/M, and subG1 populations and induced internucleosomal DNA fragmentation. ?-T3 treatment also increased the levels of cleaved caspase-3, -6, -7, -9, and poly-ADP ribose polymerase (PARP), and this was accompanied by downregulation of Bcl-2, Bcl-xL, and XIAP. Moreover, ?-T3 decreased nuclear p65 NF-?B levels, indicating downregulation of NF-?B activity. This cytotoxic effect of ?-T3 was abrogated by squalene (SQL) but not mevalonate (MVL), farnesyl diphosphate (FPP), geranylgeranyl diphosphate (GGPP), or cholesterol (CL). ?-T3 decreased intracellular SQL levels, and inhibition of de novo cholesterol synthesis did not affect the action of SQL. Furthermore, ?-T3 significantly decreased farnesyl-diphosphate farnesyltransferase 1 (FDFT1) expression. Taken together, it is evident that ?-T3, due to its ability to potently induce apoptosis via the depletion of intracellular SQL, shows the potential to be considered a therapeutic agent in patients with ATL. PMID:25225850

  4. Dependence receptor UNC5D mediates nerve growth factor depletioninduced neuroblastoma regression

    PubMed Central

    Zhu, Yuyan; Li, Yuanyuan; Haraguchi, Seiki; Yu, Meng; Ohira, Miki; Ozaki, Toshinori; Nakagawa, Atsuko; Ushijima, Toshikazu; Isogai, Eriko; Koseki, Haruhiko; Nakamura, Yohko; Kong, Cuize; Mehlen, Patrick; Arakawa, Hirofumi; Nakagawara, Akira

    2013-01-01

    Spontaneous regression of neuroblastoma (NB) resembles the developmentally regulated programmed cell death (PCD) of sympathetic neurons. Regressing tumor cells express high levels of the nerve growth factor (NGF) receptors TRKA and p75NTR and are dependent on NGF for survival; however, the underlying molecular mechanism remains elusive. Here, we show that UNC5D, a dependence receptor that is directly targeted by p53 family members, is highly expressed in favorable NBs. NGF withdrawal strongly upregulated UNC5D, E2F1, and p53 in human primary favorable NBs. The induced UNC5D was cleaved by caspases 2/3, and the released intracellular fragment translocated into the nucleus and interacted with E2F1 to selectively transactivate the proapoptotic target gene. The cleavage of UNC5D and its induction of apoptosis were strongly inhibited by addition of netrin-1. Unc5d/ mice consistently exhibited a significant increase in dorsal root ganglia neurons and resistance to NGF depletioninduced apoptosis in sympathetic neurons compared with wild-type cells. Our data suggest that UNC5D forms a positive feedback loop with p53 and E2F1 to promote NGF dependencemediated PCD during NB regression. PMID:23778138

  5. Dopamine, Working Memory, and Training Induced Plasticity: Implications for Developmental Research

    ERIC Educational Resources Information Center

    Soderqvist, Stina; Bergman Nutley, Sissela; Peyrard-Janvid, Myriam; Matsson, Hans; Humphreys, Keith; Kere, Juha; Klingberg, Torkel

    2012-01-01

    Cognitive deficits and particularly deficits in working memory (WM) capacity are common features in neuropsychiatric disorders. Understanding the underlying mechanisms through which WM capacity can be improved is therefore of great importance. Several lines of research indicate that dopamine plays an important role not only in WM function but also

  6. Dopamine, Working Memory, and Training Induced Plasticity: Implications for Developmental Research

    ERIC Educational Resources Information Center

    Soderqvist, Stina; Bergman Nutley, Sissela; Peyrard-Janvid, Myriam; Matsson, Hans; Humphreys, Keith; Kere, Juha; Klingberg, Torkel

    2012-01-01

    Cognitive deficits and particularly deficits in working memory (WM) capacity are common features in neuropsychiatric disorders. Understanding the underlying mechanisms through which WM capacity can be improved is therefore of great importance. Several lines of research indicate that dopamine plays an important role not only in WM function but also…

  7. Unilateral Lesion of Dopamine Neurons Induces Grooming Asymmetry in the Mouse

    PubMed Central

    Pelosi, Assunta; Girault, Jean-Antoine; Hervé, Denis

    2015-01-01

    Grooming behaviour is the most common innate behaviour in animals. In rodents, it consists of sequences of movements organized in four phases, executed symmetrically on both sides of the animal and creating a syntactic chain of behavioural events. The grooming syntax can be altered by stress and novelty, as well as by several mutations and brain lesions. Grooming behaviour is known to be affected by alterations of the dopamine system, including dopamine receptor modulation, dopamine alteration in genetically modified animals, and after brain lesion. While a lot is known about the initiation and syntactic modifications of this refined sequence of movements, effects of unilateral lesion of dopamine neurons are unclear particularly regarding the symmetry of syntactic chains. In the present work we studied grooming in mice unilaterally lesioned in the medial forebrain bundle by 6-hydroxydopamine. We found a reduction in completion of grooming bouts, associated with reduction in number of transitions between grooming phases. The data also revealed the development of asymmetry in grooming behaviour, with reduced tendency to groom the contralateral side to the lesion. Symmetry was recovered following treatment with L-DOPA. Thus, the present work shows that unilateral lesion of dopamine neurons reduces self-grooming behaviour by affecting duration and numbers of events. It produces premature discontinuation of grooming chains but the sequence syntax remains correct. This deficient grooming could be considered as an intrinsic symptom of Parkinson’s disease in animal models and could present some similarities with abnormalities of motor movement sequencing seen in patients. Our study also suggests grooming analysis as an additional method to screen parkinsonism in animal models. PMID:26397369

  8. Effects of dopamine agonists and antagonists on cocaine-induced operant responding for a cocaine-associated stimulus.

    PubMed

    Weissenborn, R; Deroche, V; Koob, G F; Weiss, F

    1996-08-01

    The present study examined the effects of receptor subtype-selective dopamine agonists and antagonists on (i) cocaine-induced responding for a cocaine-associated stimulus and (ii) on responding for food and cocaine reinforcement. Rats implanted with intravenous catheters were trained to lever-press for food or cocaine reinforcers on an FR5-FR5 multiple schedule, which was preceded by a 5-min component during which only stimuli previously associated with the primary reinforcers were available response-contingently. (i) Non-contingent delivery of cocaine at the beginning of the stimulus component significantly increased responding for the cocaine-associated stimulus, compared to responding for the food-associated cue. Changes in the dose of cocaine administered non-contingently before the stimulus component resulted in an inverted U-shaped dose-effect curve in responding for the cocaine-associated cue. In subsequent experiments, pretreatment with the dopamine D2 receptor agonist bromocriptine (4.0-16.0 mg/kg IP) attenuated the cocaine-induced increase in responding for the cocaine-associated cue. In contrast, pretreatment with low doses of SDZ 208-911, a dopamine D2 partial agonist (0.025-0.1 mg/kg SC), further potentiated the cocaine-induced response. Pretreatment with low and medium doses of the dopamine D1 and D2 receptor subtype-selective antagonists SCH 23390 (D1; 5-10 micrograms/kg SC) and raclopride (D2; 100-200 micrograms/kg SC) blocked responding for cocaine-associated cues, with SCH 23390 acting more selectively than raclopride. At higher doses (SCH 23390: 20 micrograms/kg SC; raclopride: 400 micrograms/kg SC), both drugs produced non-selective effects by inhibiting responses for the food-associated cue. (ii) Varying the dose of cocaine self-administered during the multiple schedule resulted in an inverted U-shaped dose-effect curve during the cocaine components, while the number of food pellets earned remained unchanged. Pretreatment with bromocriptine selectively reduced the number of cocaine infusions obtained. The compensatory increases in responding for cocaine typically associated with SCH 23390, raclopride or SDZ 208-911 pretreatment were also observed under the present schedule conditions, although the effect did not reach statistical significance in the case of SCH 23390 and raclopride, possibly due to methodological constraints. The results indicate that the present rat model of cocaine-seeking behavior is sensitive to pharmacological manipulations and may yield important information regarding the neurobiological mechanisms underlying conditioned and unconditioned reinforcing aspects of cocaine addiction. PMID:8878347

  9. Relationship between dopamine transporter occupancy and methylphenidate induced high in humans

    SciTech Connect

    Volkow, N.D.; Wang, G.J.; Fowler, J.S. |

    1996-05-01

    The inhibition of the dopamine transporter (DAT) by cocaine has been shown to be indispensable for its reinforcing properties. The development of drugs that inibit the DAT has become a major target to prevent cocaine`s effects. However prevention of the {open_quotes}high{close_quotes} by DAT inhibitors has never been demonstrated. This study evaluates the ability to block methylphenidate (MP), a DAT inhibitor drug with similar reinforcing properties to cocaine, induced {open_quotes}high{close_quotes} by prior DAT inhibition. It uses PET and [{sup 11}C]d-threo-methylphenidate to measure the relationship between DAT occupancy prior to administration of MP and the intensity of the subjective perception of the {open_quotes}high{close_quotes} in 8 controls. MP (0.375 mg/kg iv) which was administered as a single injection and also as two sequential doses given 60 minutes apart significantly reduced the ratio of the distribution volume for [{sup 11}C]d-threo-methylphenidate in striatum to that in cerebellum from a baseline of 2.83 {plus_minus} 0.2 to 1.29 {plus_minus} 0.1 at 7 minutes and to 1.37 {plus_minus} 0.2 at 60 minutes after a single injection of MP and to 1.14 {plus_minus} 0.1 at 7 minutes after the second of two sequential MP doses. This corresponds to a DAT occupancy by MP of 84% {plus_minus} 7 at 7 minutes and of 77% {plus_minus} 6 at 60 minutes after a single injection of MP and of 93% {plus_minus} 7 at 7 after the second of two sequential MP doses. The subjective perception of {open_quotes}high{close_quotes} experienced after the second injection of MP was of a similar magnitude to that experienced after the first injection of MP was of a similar magnitude to that experienced after the first injection, in spite of the very different starting DAT occupancies (0 and 77%, respectively). DAT occupancy was not correlated with the {open_quotes}high{close_quotes}; and one subject with 100% DAT occupancy did not perceive the {open_quotes}high{close_quotes}.

  10. Delta-9-Tetrahydrocannabinol-Induced Dopamine Release as a Function of Psychosis Risk: 18F-Fallypride Positron Emission Tomography Study

    PubMed Central

    Kuepper, Rebecca; Ceccarini, Jenny; Lataster, Johan; van Os, Jim; van Kroonenburgh, Marinus; van Gerven, Joop M. A.; Marcelis, Machteld; Van Laere, Koen; Henquet, Cécile

    2013-01-01

    Cannabis use is associated with psychosis, particularly in those with expression of, or vulnerability for, psychotic illness. The biological underpinnings of these differential associations, however, remain largely unknown. We used Positron Emission Tomography and 18F-fallypride to test the hypothesis that genetic risk for psychosis is expressed by differential induction of dopamine release by Δ9-THC (delta-9-tetrahydrocannabinol, the main psychoactive ingredient of cannabis). In a single dynamic PET scanning session, striatal dopamine release after pulmonary administration of Δ9-THC was measured in 9 healthy cannabis users (average risk psychotic disorder), 8 patients with psychotic disorder (high risk psychotic disorder) and 7 un-related first-degree relatives (intermediate risk psychotic disorder). PET data were analyzed applying the linear extension of the simplified reference region model (LSRRM), which accounts for time-dependent changes in 18F-fallypride displacement. Voxel-based statistical maps, representing specific D2/3 binding changes, were computed to localize areas with increased ligand displacement after Δ9-THC administration, reflecting dopamine release. While Δ9-THC was not associated with dopamine release in the control group, significant ligand displacement induced by Δ9-THC in striatal subregions, indicative of dopamine release, was detected in both patients and relatives. This was most pronounced in caudate nucleus. This is the first study to demonstrate differential sensitivity to Δ9-THC in terms of increased endogenous dopamine release in individuals at risk for psychosis. PMID:23936196

  11. Delta-9-tetrahydrocannabinol-induced dopamine release as a function of psychosis risk: 18F-fallypride positron emission tomography study.

    PubMed

    Kuepper, Rebecca; Ceccarini, Jenny; Lataster, Johan; van Os, Jim; van Kroonenburgh, Marinus; van Gerven, Joop M A; Marcelis, Machteld; Van Laere, Koen; Henquet, Cécile

    2013-01-01

    Cannabis use is associated with psychosis, particularly in those with expression of, or vulnerability for, psychotic illness. The biological underpinnings of these differential associations, however, remain largely unknown. We used Positron Emission Tomography and (18)F-fallypride to test the hypothesis that genetic risk for psychosis is expressed by differential induction of dopamine release by Δ(9)-THC (delta-9-tetrahydrocannabinol, the main psychoactive ingredient of cannabis). In a single dynamic PET scanning session, striatal dopamine release after pulmonary administration of Δ(9)-THC was measured in 9 healthy cannabis users (average risk psychotic disorder), 8 patients with psychotic disorder (high risk psychotic disorder) and 7 un-related first-degree relatives (intermediate risk psychotic disorder). PET data were analyzed applying the linear extension of the simplified reference region model (LSRRM), which accounts for time-dependent changes in (18)F-fallypride displacement. Voxel-based statistical maps, representing specific D2/3 binding changes, were computed to localize areas with increased ligand displacement after Δ(9)-THC administration, reflecting dopamine release. While Δ(9)-THC was not associated with dopamine release in the control group, significant ligand displacement induced by Δ(9)-THC in striatal subregions, indicative of dopamine release, was detected in both patients and relatives. This was most pronounced in caudate nucleus. This is the first study to demonstrate differential sensitivity to Δ(9)-THC in terms of increased endogenous dopamine release in individuals at risk for psychosis. PMID:23936196

  12. Dextroamphetamine (but Not Atomoxetine) Induces Reanimation from General Anesthesia: Implications for the Roles of Dopamine and Norepinephrine in Active Emergence

    PubMed Central

    Kenny, Jonathan D.; Taylor, Norman E.; Brown, Emery N.; Solt, Ken

    2015-01-01

    Methylphenidate induces reanimation (active emergence) from general anesthesia in rodents, and recent evidence suggests that dopaminergic neurotransmission is important in producing this effect. Dextroamphetamine causes the direct release of dopamine and norepinephrine, whereas atomoxetine is a selective reuptake inhibitor for norepinephrine. Like methylphenidate, both drugs are prescribed to treat Attention Deficit Hyperactivity Disorder. In this study, we tested the efficacy of dextroamphetamine and atomoxetine for inducing reanimation from general anesthesia in rats. Emergence from general anesthesia was defined by return of righting. During continuous sevoflurane anesthesia, dextroamphetamine dose-dependently induced behavioral arousal and restored righting, but atomoxetine did not (n = 6 each). When the D1 dopamine receptor antagonist SCH-23390 was administered prior to dextroamphetamine under the same conditions, righting was not restored (n = 6). After a single dose of propofol (8 mg/kg IV), the mean emergence times for rats that received normal saline (vehicle) and dextroamphetamine (1 mg/kg IV) were 641 sec and 404 sec, respectively (n = 8 each). The difference was statistically significant. Although atomoxetine reduced mean emergence time to 566 sec (n = 8), this decrease was not statistically significant. Spectral analysis of electroencephalogram recordings revealed that dextroamphetamine and atomoxetine both induced a shift in peak power from ? (0.14 Hz) to ? (48 Hz) during continuous sevoflurane general anesthesia, which was not observed when animals were pre-treated with SCH-23390. In summary, dextroamphetamine induces reanimation from general anesthesia in rodents, but atomoxetine does not induce an arousal response under the same experimental conditions. This supports the hypothesis that dopaminergic stimulation during general anesthesia produces a robust behavioral arousal response. In contrast, selective noradrenergic stimulation causes significant neurophysiological changes, but does not promote behavioral arousal during general anesthesia. We hypothesize that dextroamphetamine is more likely than atomoxetine to be clinically useful for restoring consciousness in anesthetized patients, mainly due to its stimulation of dopaminergic neurotransmission. PMID:26148114

  13. Radiation hardening and radiation-induced chromium depletion effects on intergranular stress corrosion cracking of austenitic stainless steels

    SciTech Connect

    Bruemmer, S.M.; Simonen, E.P.

    1993-03-01

    Available data on neutron-irradiated materials have been analyzed and correlations developed between fluence, yield strength, grain boundary chromium concentration and cracking susceptibility in high-temperature water environments. Large heat-to-heat differences in critical fluence (0.2 to 2.5 n/cm{sup 2}) for IGSCC are documented.In many cases, this variability is consistent with yield strength differences among irradiated materials. IGSCC correlated better to yield strength than to fluence for most heats suggesting a possible role of the radiation-induced hardening (and microstructure) on cracking. However, isolatedheats reveal a wide range of yield strengths from 450 to 800 MPa necessary to promote IGSCC which cannot be understood by strength effects alone. Grain boundary Cr depletion explain differences in IGSCC susceptibility for irradiated stainless steels. Cr contents versus SCC shows that all materials showing IG cracking have some grain boundary depletion ({ge}2%). Grain boundary Cr concentrations for cracking (below {approximately}16 wt %) are in good agreement with similar SCC tests on unirradiated 304 SS with controlled depletion profiles. Heats that prompt variability in the yield strength correlation, are accounted for bydifferences in their interfacial Cr contents. Certain stainless steels are more resistant to cracking even though they have significant radiation-induced Cr depletion. It is proposed that Cr depletion is required for IASCC, but observed susceptibility is modified by other microchemical and microstructural components.

  14. Radiation hardening and radiation-induced chromium depletion effects on intergranular stress corrosion cracking of austenitic stainless steels

    SciTech Connect

    Bruemmer, S.M.; Simonen, E.P.

    1993-03-01

    Available data on neutron-irradiated materials have been analyzed and correlations developed between fluence, yield strength, grain boundary chromium concentration and cracking susceptibility in high-temperature water environments. Large heat-to-heat differences in critical fluence (0.2 to 2.5 n/cm[sup 2]) for IGSCC are documented.In many cases, this variability is consistent with yield strength differences among irradiated materials. IGSCC correlated better to yield strength than to fluence for most heats suggesting a possible role of the radiation-induced hardening (and microstructure) on cracking. However, isolatedheats reveal a wide range of yield strengths from 450 to 800 MPa necessary to promote IGSCC which cannot be understood by strength effects alone. Grain boundary Cr depletion explain differences in IGSCC susceptibility for irradiated stainless steels. Cr contents versus SCC shows that all materials showing IG cracking have some grain boundary depletion ([ge]2%). Grain boundary Cr concentrations for cracking (below [approximately]16 wt %) are in good agreement with similar SCC tests on unirradiated 304 SS with controlled depletion profiles. Heats that prompt variability in the yield strength correlation, are accounted for bydifferences in their interfacial Cr contents. Certain stainless steels are more resistant to cracking even though they have significant radiation-induced Cr depletion. It is proposed that Cr depletion is required for IASCC, but observed susceptibility is modified by other microchemical and microstructural components.

  15. Reversal effect of DM-9384 on scopolamine-induced acetylcholine depletion in certain regions of the mouse brain.

    PubMed

    Abe, E

    1991-01-01

    The effect of a new cognition enhancer, DM-9384, N-(2,6-dimethylphenyl)-2-(2-oxo-1-pyrrolidinyl) acetamide, on regional acetylcholine (ACh) levels and against scopolamine-induced ACh depletion was examined in mouse brain. In addition, the effects of DM-9384 were compared with those of oxiracetam, physostigmine and tacrine. Independent administration of DM-9384 (1, 3, 10 or 30 mg/kg, PO) or oxiracetam (10 or 50 mg/kg, PO) to mice had no effect on the ACh level in the hippocampus, frontal cortex, amygdala and striatum. Nevertheless, in all brain regions, pretreatment with DM-9384 significantly reduced the depletion of ACh induced by scopolamine (0.5 mg/kg, IP) in a nondose-related bell-shaped manner. By contrast, oxiracetam attenuated the effect of scopolamine in the hippocampus, frontal cortex and striatum but not in the amygdala. Physostigmine (0.2 mg/kg, SC) significantly increased ACh levels and reversed the scopolamine-induced ACh depletion in all brain regions. Unlike physostigmine, tacrine (10 mg/kg, PO) increased ACh levels in the striatum but not in the other regions. Tacrine reversed the effect of scopolamine in the hippocampus, amygdala and striatum, but not in the frontal cortex. In the present study, DM-9384 more effectively inhibited scopolamine-induced depletion of ACh levels than the other agents tested. The results obtained indicate that the protective action of DM-9384 against scopolamine-induced amnesia is due to its ability to reverse the ACh depletion. PMID:1798828

  16. Catalepsy-associated behavior induced by dopamine D1 receptor antagonists and partial dopamine D1 receptor agonists in squirrel monkeys.

    PubMed

    Rosenzweig-Lipson, S; Bergman, J

    1994-08-01

    Observational procedures were used to compare the behavioral effects of dopamine D1 receptor antagonists and partial dopamine D1 receptor agonists in squirrel monkeys. The dopamine D1 receptor antagonists SCH 39166 ((-)-trans-6-7,7a,8,9,13b-hexahydro-3-chloro-2-hydroxy-N- methyl-5H-benzo(d)naphtho-(2,1-b)azepine) and BW 737C89 ([S]-6-chloro-1-[2,5-dimethoxy-4-propylbenzyl]-7- hydroxy-2-methyl-1,2,3,4-tetrahydroisoquinoline) produced dose-related increases in the duration of static and unusual postures, indicative of catalepsy. R-SKF 38393 (R(+)-7,8- dihydroxy-1-phenyl-2,3,4,5-tetrahydro-[1H]-3-benzazepine) and SKF 75670 (7,8-dihydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-[1H]-3- benzazepine), which are considered partial dopamine D1 receptor agonists, also consistently produced dose-related increases in catalepsy-associated behavior and had effects comparable in magnitude to those of dopamine D1 receptor antagonists. In contrast, the higher efficacy D1 agonists SKF 81297 (6-chloro-7,8-dihydroxy-1-phenyl-2,3,4,5-tetrahydro-[1H]-3- benzazepine) and SKF 82958 (6-chloro-7,8-dihydroxy-1-phenyl-2,3,4,5-tetrahydro-3-allyl-[1H]-3- benzazepine) did not produce catalepsy-associated behavior at any dose tested. The results indicate that dopamine D1 agonists differ with respect to cataleptogenic activity, possibly reflecting differences in intrinsic activity. PMID:7988649

  17. Pharmacology of Signaling Induced by Dopamine D1-Like Receptor Activation

    PubMed Central

    Undieh, Ashiwel S.

    2010-01-01

    Dopamine D1-like receptors consisting of D1 and D5 subtypes are intimately implicated in dopaminergic regulation of fundamental neurophysiologic processes such as mood, motivation, cognitive function, and motor activity. Upon stimulation, D1-like receptors initiate signal transduction cascades that are mediated through adenylyl cyclase or phosphoinositide metabolism, with subsequent enhancement of multiple downstream kinase cascades. The latter actions propagate and further amplify the receptor signals, thus predisposing D1-like receptors to multifaceted interactions with various other mediators and receptor systems. The adenylyl cyclase response to dopamine or selective D1-like receptor agonists is reliably associated with the D1 subtype, while emerging evidence indicates that the phosphoinositide responses in native brain tissues may be preferentially mediated through stimulation of the D5 receptor. Besides classic coupling of each receptor subtype to specific G proteins, additional biophysical models are advanced in attempts to account for differential subcellular distribution, heteromolecular oligomerization, and activity-dependent selectivity of the receptors. It is expected that significant advances in understanding of dopamine neurobiology will emerge from current and anticipated studies directed at uncovering the molecular mechanisms of D5 coupling to phosphoinositide signaling, the structural features that might enhance pharmacological selectivity for D5 versus D1 subtypes, the mechanism by which dopamine may modulate phosphoinositide synthesis, the contributions of the various responsive signal mediators to D1 or D5 interactions with D2-like receptors, and the spectrum of dopaminergic functions that may be attributed to each receptor subtype and signaling pathway. PMID:20547182

  18. Depleted uranium induces disruption of energy homeostasis and oxidative stress in isolated rat brain mitochondria.

    PubMed

    Shaki, Fatemeh; Hosseini, Mir-Jamal; Ghazi-Khansari, Mahmoud; Pourahmad, Jalal

    2013-06-01

    Depleted uranium (DU) is emerging as an environmental pollutant primarily due to its military applications. Gulf War veterans with embedded DU showed cognitive disorders that suggest that the central nervous system is a target of DU. Recent evidence has suggested that DU could induce oxidative stress and mitochondrial dysfunction in brain tissue. However, the underlying mechanisms of DU toxicity in brain mitochondria are not yet well understood. Brain mitochondria were obtained using differential centrifugation and were incubated with different concentrations (50, 100 and 200 μM) of uranyl acetate (UA) as a soluble salt of U(238) for 1 h. In this research, mitochondrial ROS production, collapse of mitochondrial membrane potential and mitochondrial swelling were examined by flow cytometry following the addition of UA. Meanwhile, mitochondrial sources of ROS formation were determined using specific substrates and inhibitors. Complex II and IV activity and also the extent of lipid peroxidation and glutathione (GSH) oxidation were detected via spectroscopy. Furthermore, we investigated the concentration of ATP and ATP/ADP ratio using luciferase enzyme and cytochrome c release from mitochondria which was detected by ELISA kit. UA caused concentration-dependent elevation of succinate-linked mitochondrial ROS production, lipid peroxidation, GSH oxidation and inhibition of mitochondrial complex II. UA also induced mitochondrial permeability transition, ATP production decrease and increase in cytochrome c release. Pre-treatment with antioxidants significantly inhibited all the above mentioned toxic effects of UA. This study suggests that mitochondrial oxidative stress and impairment of oxidative phosphorylation in brain mitochondria may play a key role in DU neurotoxicity as reported in Gulf War Syndrome. PMID:23629690

  19. Reward-Induced Phasic Dopamine Release in the Monkey Ventral Striatum and Putamen

    PubMed Central

    Weitemier, Adam; Inoue, Masato

    2015-01-01

    In-vivo voltammetry has successfully been used to detect dopamine release in rodent brains, but its application to monkeys has been limited. We have previously detected dopamine release in the caudate of behaving Japanese monkeys using diamond microelectrodes (Yoshimi 2011); however it is not known whether the release pattern is the same in various areas of the forebrain. Recent studies have suggested variations in the dopaminergic projections to forebrain areas. In the present study, we attempted simultaneous recording at two locations in the striatum, using fast-scan cyclic voltammetry (FSCV) on carbon fibers, which has been widely used in rodents. Responses to unpredicted food and liquid rewards were detected repeatedly. The response to the liquid reward after conditioned stimuli was enhanced after switching the prediction cue. These characteristics were generally similar between the ventral striatum and the putamen. Overall, the technical application of FSCV recording in multiple locations was successful in behaving primates, and further voltammetric recordings in multiple locations will expand our knowledge of dopamine reward responses. PMID:26110516

  20. Dopamine mediates testosterone-induced social reward in male Syrian hamsters.

    PubMed

    Bell, Margaret R; Sisk, Cheryl L

    2013-03-01

    Adolescent maturation of responses to social stimuli is essential for adult-typical sociosexual behavior. Naturally occurring developmental changes in male Syrian hamster responses to a salient social cue, female hamster vaginal secretions (VS), provide a good model system for investigating neuroendocrine mechanisms of adolescent change in social reward. Sexually naïve adult, but not juvenile, males show a conditioned place preference (CPP) to VS, indicating that VS is not rewarding before puberty. In this series of experiments, the authors examined the roles of testosterone and dopamine receptor activation in mediating the adolescent gain in positive valence of VS. Experiment 1 showed that testosterone replacement is necessary for gonadectomized adult hamsters to form a CPP to VS. Experiment 2 showed that testosterone treatment is sufficient for juvenile hamsters to form a CPP to VS, and that the dopamine receptor antagonist haloperidol blocks formation of a CPP to VS in these animals. Experiments 3 and 4 demonstrated that the disruption of VS CPP with low doses of haloperidol is the result of a reduction in the attractive properties of VS and not attributable to aversive properties of haloperidol. Together, these studies demonstrate that the unconditioned rewarding properties of a social cue necessary for successful adult sociosexual interactions come about as the result of the pubertal increase in circulating testosterone in male hamsters. Furthermore, this social reward can be prevented by dopamine receptor antagonism, indicating that hypothalamic and/or mesocorticolimbic dopaminergic circuits are targets for hormonal activation of social reward. PMID:23372017

  1. Anti-dopamine beta-hydroxylase immunotoxin-induced sympathectomy in adult rats

    NASA Technical Reports Server (NTRS)

    Picklo, M. J.; Wiley, R. G.; Lonce, S.; Lappi, D. A.; Robertson, D.

    1995-01-01

    Anti-dopamine beta-hydroxylase immunotoxin (DHIT) is an antibody-targeted noradrenergic lesioning tool comprised of a monoclonal antibody against the noradrenergic enzyme, dopamine beta-hydroxylase, conjugated to saporin, a ribosome-inactivating protein. Noradrenergic-neuron specificity and completeness and functionality of sympathectomy were assessed. Adult, male Sprague-Dawley rats were given 28.5, 85.7, 142 or 285 micrograms/kg DHIT i.v. Three days after injection, a 6% to 73% decrease in the neurons was found in the superior cervical ganglia of the animals. No loss of sensory, nodose and dorsal root ganglia, neurons was observed at the highest dose of DHIT. In contrast, the immunotoxin, 192-saporin (142 micrograms/kg), lesioned all three ganglia. To assess the sympathectomy, 2 wk after treatment (285 micrograms/kg), rats were anesthetized with urethane (1 g/kg) and cannulated in the femoral artery and vein. DHIT-treated animals' basal systolic blood pressure and heart rate were significantly lower than controls. Basal plasma norepinephrine levels were 41% lower in DHIT-treated animals than controls. Tyramine-stimulated release of norepinephrine in DHIT-treated rats was 27% of controls. Plasma epinephrine levels of DHIT animals were not reduced. DHIT-treated animals exhibited a 2-fold hypersensitivity to the alpha-adrenergic agonist phenylephrine. We conclude that DHIT selectively delivered saporin to noradrenergic neurons resulting in destruction of these neurons. Anti-dopamine beta-hydroxylase immunotoxin administration produces a rapid, irreversible sympathectomy.

  2. Effect of new dopamine-blocking agent (oxiperomide) on drug-induced dyskinesias in Parkinson's disease and spontaneous dyskinesias.

    PubMed Central

    Bdard, P; Parkes, J D; Marsden, C D

    1978-01-01

    Oxiperomide, a new dopamine-receptor antagonist, was found to decrease dyskinesias in patients with Parkinson's disease receiving levodopa or other dopamine agonists without necessarily increasing Parkinsonian symptoms. Oxiperomide also decreased spontaneous dyskinesias in those with tics and chorea and to a less extent in those with torsion dystonia, without necessarily causing Parkinsonism. These results provide evidence that more than one population of dopamine receptors exist in the extra pyramidal system, and encourage the search for selective dopamine antagonists. PMID:638546

  3. Measurement of quantal secretion induced by ouabain and its correlation with depletion of synaptic vesicles

    PubMed Central

    1985-01-01

    Ouabain (0.1 and 0.05 mM) was applied to frog cutaneous pectoris nerve- muscle preparations bathed in modified Ringer's solution containing either 1.8 mM Ca2+ (and 4 mM Mg2+) or no added Ca2+ (4 mM Mg2+ and 1 mM EGTA). During the intense quantal release of acetylcholine (ACh) induced by ouabain, the parameters of the miniature endplate potentials (mepps) were deduced from the variance, skew, and power spectra of the endplate recordings by applying a recently described modification of classical fluctuation analysis. Often the high frequency of mepps is not stationary; therefore, the signal was high-pass filtered (time constant of the resistance-capacitance filter of 2 ms) to remove the errors introduced by nonstationarity. When ouabain was applied in the presence of Ca2+, mepp frequency started to rise exponentially after a lag of 1.5-2 h, reached an average peak frequency of 1,300/s in approximately 30 min, and then suddenly subsided to low level (10/s). In Ca2+-free solution, after a shorter lag (1-1.5 h), mepp frequency rose to peak rate of 700/s in approximately 20 min and then gradually subsided. In spite of the different time course of secretion in the two experimental conditions, the cumulative quantal release was not significantly different (7.4 +/- 1.3 X 10(5) in Ca2+-containing and 8.8 +/- 2.7 X 10(5) in Ca2+-free solutions). 60 min after the peak secretion, the muscles were fixed for observation in the electron microscope. Morphometric analysis on micrographs of neuromuscular junctions revealed in both cases a profound depletion of synaptic vesicles and deep infoldings of presynaptic membrane. This rapid depletion and the lack of uptake of horseradish peroxidase suggest that ouabain impairs the recycling process that tends to conserve the vesicle population during intense secretion of neurotransmitter. The good correlation observed between the reduction in the store of synaptic vesicles and the total number of quanta of ACh secreted in the absence of a vigorous membrane recycling strongly supports the view that the secretion of a quantum of ACh requires the fusion of a synaptic vesicle with the axolemma. PMID:3932368

  4. Store depletion induces G?q-mediated PLC?1 activity to stimulate TRPC1 channels in vascular smooth muscle cells

    PubMed Central

    Shi, Jian; Miralles, Francesc; Birnbaumer, Lutz; Large, William A.; Albert, Anthony P.

    2016-01-01

    Depletion of sarcoplasmic reticulum (SR) Ca2+ stores activates store-operated channels (SOCs) composed of canonical transient receptor potential (TRPC) 1 proteins in vascular smooth muscle cells (VSMCs), which contribute to important cellular functions. We have previously shown that PKC is obligatory for activation of TRPC1 SOCs in VSMCs, and the present study investigates if the classic phosphoinositol signaling pathway involving G?q-mediated PLC activity is responsible for driving PKC-dependent channel gating. The G-protein inhibitor GDP-?-S, anti-G?q antibodies, the PLC inhibitor U73122, and the PKC inhibitor GF109203X all inhibited activation of TRPC1 SOCs, and U73122 and GF109203X also reduced store-operated PKC-dependent phosphorylation of TRPC1 proteins. Three distinct SR Ca2+ store-depleting agents, 1,2-bis(2-aminophenoxy)ethane-N,N,N?,N?-tetraacetic acid acetoxymethyl ester, cyclopiazonic acid, and N,N,N?,N?-tetrakis(2-pyridylmethyl)ethane-1,2-diamineed, induced translocations of the fluorescent biosensor GFP-PLC?1-PH from the cell membrane to the cytosol, which were inhibited by U73122. Knockdown of PLC?1 with small hairpin RNA reduced both store-operated PLC activity and stimulation of TRPC1 SOCs. Immunoprecipitation studies and proximity ligation assays revealed that store depletion induced interactions between TRPC1 and G?q, and TRPC1 and PLC?1. We propose a novel activation mechanism for TRPC1 SOCs in VSMCs, in which store depletion induces formation of TRPC1-G?q-PLC?1 complexes that lead to PKC stimulation and channel gating.Shi, J., Miralles, F., Birnbaumer, L., Large, W. A., Albert, A. P. Store depletion induces G?q-mediated PLC?1 activity to stimulate TRPC1 channels in vascular smooth muscle cells. PMID:26467792

  5. Store depletion induces G?q-mediated PLC?1 activity to stimulate TRPC1 channels in vascular smooth muscle cells.

    PubMed

    Shi, Jian; Miralles, Francesc; Birnbaumer, Lutz; Large, William A; Albert, Anthony P

    2016-02-01

    Depletion of sarcoplasmic reticulum (SR) Ca(2+) stores activates store-operated channels (SOCs) composed of canonical transient receptor potential (TRPC) 1 proteins in vascular smooth muscle cells (VSMCs), which contribute to important cellular functions. We have previously shown that PKC is obligatory for activation of TRPC1 SOCs in VSMCs, and the present study investigates if the classic phosphoinositol signaling pathway involving G?q-mediated PLC activity is responsible for driving PKC-dependent channel gating. The G-protein inhibitor GDP-?-S, anti-G?q antibodies, the PLC inhibitor U73122, and the PKC inhibitor GF109203X all inhibited activation of TRPC1 SOCs, and U73122 and GF109203X also reduced store-operated PKC-dependent phosphorylation of TRPC1 proteins. Three distinct SR Ca(2+) store-depleting agents, 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid acetoxymethyl ester, cyclopiazonic acid, and N,N,N',N'-tetrakis(2-pyridylmethyl)ethane-1,2-diamineed, induced translocations of the fluorescent biosensor GFP-PLC?1-PH from the cell membrane to the cytosol, which were inhibited by U73122. Knockdown of PLC?1 with small hairpin RNA reduced both store-operated PLC activity and stimulation of TRPC1 SOCs. Immunoprecipitation studies and proximity ligation assays revealed that store depletion induced interactions between TRPC1 and G?q, and TRPC1 and PLC?1. We propose a novel activation mechanism for TRPC1 SOCs in VSMCs, in which store depletion induces formation of TRPC1-G?q-PLC?1 complexes that lead to PKC stimulation and channel gating.-Shi, J., Miralles, F., Birnbaumer, L., Large, W. A., Albert, A. P. Store depletion induces G?q-mediated PLC?1 activity to stimulate TRPC1 channels in vascular smooth muscle cells. PMID:26467792

  6. Dopamine D3 receptor ligands show place conditioning effect but do not influence cocaine-induced place preference.

    PubMed

    Gyertyn, Istvn; Gl, Krisztina

    2003-01-20

    The importance of dopamine D3 receptors in reward related processes, especially in cocaine addiction, has been investigated extensively. However, in the reported studies a combination of different experimental conditions and different ligands have been used which renders the interpretation and comparison of the diverse results extremely difficult. Here, we report one comparative study investigating a wide range of dopamine D3 receptor ligands in one model of cocaine abuse: the place conditioning paradigm in rats. Of the antagonists tested, the moderately D3 selective nafadotride and the more selective SB-277011 did not produce any place conditioning effect while U-99194A caused place-preference. The most D3 selective agonist PD-128907, the less selective 7-OH-DPAT and the moderately selective partial agonist BP-897 all caused significant place aversion. None of the compounds influenced the cocaine-induced place preference. Results suggest the D3-preferring agonists could affect the reward mechanisms of the brain, however, modulation of D3 receptor function does not appear to be a significant mechanism for modifying the place conditioning effect of cocaine. PMID:12544838

  7. Glyceraldehyde 3-Phosphate Dehydrogenase Depletion Induces Cell Cycle Arrest and Resistance to Antimetabolites in Human Carcinoma Cell LinesS?

    PubMed Central

    Phadke, Manali S.; Krynetskaia, Natalia F.; Mishra, Anurag K.

    2009-01-01

    Glyceraldehyde 3-phosphate dehydrogenase (GAPDH) is a multifunctional protein that acts at the intersection of energy metabolism and stress response in tumor cells. To elucidate the role of GAPDH in chemotherapy-induced stress, we analyzed its activity, protein level, intracellular distribution, and intranuclear mobility in human carcinoma cells A549 and UO31 after treatment with cytarabine, doxorubicin, and mercaptopurine. After treatment with cytosine arabinoside (araC), enzymatically inactive GAPDH accumulated in the nucleus. Experiments on fluorescence recovery after photobleaching with green fluorescent protein-GAPDH fusion protein in the live cells treated with araC demonstrated reduced mobility of green fluorescent protein-GAPDH inside the nucleus, indicative of interactions with nuclear macromolecular components after genotoxic stress. Depletion of GAPDH with RNA interference stopped cell proliferation, and induced cell cycle arrest in G1 phase via p53 stabilization, and accumulation of p53-inducible CDK inhibitor p21. Neither p21 accumulation nor cell cycle arrest was detected in GAPDH-depleted p53-null NCI-H358 cells. GAPDH-depleted A549 cells were 50-fold more resistant to treatment with cytarabine (1.68 0.182 ?M versus 0.03 0.015 ?M in control). Depletion of GAPDH did not significantly alter cellular sensitivity to doxorubicin (0.05 0.023 ?M versus 0.035 0.0154 ?M in control). Induction of cell cycle arrest in p53-proficient carcinoma cells via GAPDH abrogation suggests that GAPDH-depleting agents may have a cytostatic effect in cancer cells. Our results define GAPDH as an important determinant of cellular sensitivity to antimetabolite chemotherapy because of its regulatory functions. PMID:19628630

  8. Treg depletion attenuates irradiation-induced pulmonary fibrosis by reducing fibrocyte accumulation, inducing Th17 response, and shifting IFN-γ, IL-12/IL-4, IL-5 balance.

    PubMed

    Xiong, Shanshan; Guo, Renfeng; Yang, Zhihua; Xu, Long; Du, Li; Li, Ruoxi; Xiao, Fengjun; Wang, Qianjun; Zhu, Maoxiang; Pan, Xiujie

    2015-11-01

    Irradiation-induced pulmonary fibrosis results from thoracic radiotherapy and severely limits radiotherapy approaches. CD4(+) CD25(+) FoxP3(+) regulatory T cells (Tregs) are involved in experimentally induced murine lung fibrosis. However, the precise contribution of Tregs to irradiation-induced pulmonary fibrosis still remains unclear. We have previously established the mouse model of irradiation-induced pulmonary fibrosis and observed an increased frequency of Tregs during the process. This study aimed to investigate the effects of Treg depletion on irradiation-induced pulmonary fibrosis and on fibrocyte, Th17 cell response and production of multiple cytokines in mice. Treg-depleted mice were generated by intraperitoneal injection with anti-CD25 mAb 2h after 20 Gy (60)CO γ-ray thoracic irradiation and every 7 days thereafter. Pulmonary fibrosis was semi-quantitatively assessed using Masson's trichrome staining. The proportions of Tregs, fibrocyte and Th17 cells were detected by flow cytometry. Th1/Th2 cytokines were assessed by Luminex assays. We found that Treg depletion decelerated the process of irradiation-induced pulmonary fibrosis and hindered fibrocyte recruitment to the lung. In response to Treg depletion, the number of CD4(+) T lymphocytes and Th17 cells increased. Moreover, Th1/Th2 cytokine balance was disturbed into Th1 dominance upon Treg depletion. Our study demonstrates that Tregs are involved in irradiation-induced pulmonary fibrosis by promoting fibrocyte accumulation, attenuating Th17 response and regulating Th1/Th2 cytokine balance in the lung tissues, which suggests that Tregs may be therapeutically manipulated to decelerate the progression of irradiation-induced pulmonary fibrosis. PMID:26224246

  9. Depleted uranium induces sex- and tissue-specific methylation patterns in adult zebrafish.

    PubMed

    Gombeau, Kewin; Pereira, Sandrine; Ravanat, Jean-Luc; Camilleri, Virginie; Cavalie, Isabelle; Bourdineaud, Jean-Paul; Adam-Guillermin, Christelle

    2016-04-01

    We examined the effects of chronic exposure to different concentrations (2 and 20 μg L(-)(1)) of environmentally relevant waterborne depleted uranium (DU) on the DNA methylation patterns both at HpaII restriction sites (5'-CCGG-3') and across the whole genome in the zebrafish brain, gonads, and eyes. We first identified sex-dependent differences in the methylation level of HpaII sites after exposure. In males, these effects were present as early as 7 days after exposure to 20 μg L(-)(1) DU, and were even more pronounced in the brain, gonads, and eyes after 24 days. However, in females, hypomethylation was only observed in the gonads after exposure to 20 μg L(-)(1) DU for 24 days. Sex-specific effects of DU were also apparent at the whole-genome level, because in males, exposure to 20 μg L(-)(1) DU for 24 days resulted in cytosine hypermethylation in the brain and eyes and hypomethylation in the gonads. In contrast, in females, hypermethylation was observed in the brain after exposure to both concentrations of DU for 7 days. Based on our current knowledge of uranium toxicity, several hypotheses are proposed to explain these findings, including the involvement of oxidative stress, alteration of demethylation enzymes and the calcium signaling pathway. This study reports, for the first time, the sex- and tissue-specific epigenetic changes that occur in a nonhuman organism after exposure to environmentally relevant concentrations of uranium, which could induce transgenerational epigenetic effects. PMID:26829549

  10. Effect of the adenosine A2A receptor antagonist MSX-3 on motivational disruptions of maternal behavior induced by dopamine antagonism in the early postpartum rat

    PubMed Central

    Farrar, Andrew M.; Hockemeyer, Jrg; Mller, Christa E.; Salamone, John D.; Morrell, Joan I.

    2011-01-01

    Rationale Mesolimbic dopamine (DA), particularly in the nucleus accumbens, importantly regulates activational aspects of maternal responsiveness. DA antagonism and accumbens DA depletions interfere with early postpartum maternal motivation by selectively affecting most forms of active maternal behaviors, while leaving nursing behavior relatively intact. Considerable evidence indicates that there is a functional interaction between DA D2 and adenosine A2A receptors in striatal areas, including the nucleus accumbens. Objective This study was conducted to determine if adenosine A2A receptor antagonism could reverse the effects of DA receptor antagonism on early postpartum maternal behavior. Methods The adenosine A2A receptor antagonist MSX-3 (0.252.0 mg/kg, IP) was investigated for its ability to reverse the effects of the DA D2 receptor antagonist haloperidol (0.1 mg/kg, IP) on the maternal behavior of early postpartum female rats. Results Haloperidol severely impaired the expression of active maternal components, including retrieval and grouping the pups at the nest site, pup licking, and nest building. Co-administration of MSX-3 (0.252.0 mg/kg, IP) with haloperidol produced a dose-related attenuation of the haloperidol-induced behavioral deficits in early postpartum females. Doses of MSX-3 that effectively reversed the effects of haloperidol (0.5, 1.0 mg/kg), when administered in the absence of haloperidol, did not affect maternal responding or locomotor activity. Conclusions Adenosine and DA systems interact to regulate early postpartum maternal responsiveness. This research may potentially contribute to the development of strategies for treatments of psychiatric disorders during the postpartum period, with particular emphasis in maintaining or restoring the motherinfant relationship. PMID:20848086

  11. Depressive-like behaviors alterations induced by intranigral MPTP, 6-OHDA, LPS and rotenone models of Parkinson's disease are predominantly associated with serotonin and dopamine.

    PubMed

    Santiago, Ronise M; Barbieiro, Janaína; Lima, Marcelo M S; Dombrowski, Patrícia A; Andreatini, Roberto; Vital, Maria A B F

    2010-08-16

    Depression is a frequently encountered non-motor feature of Parkinson's disease (PD) and it can have a significant impact on patient's quality of life. Considering the differential pathophysiology of depression in PD, it prompts the idea that a degenerated nigrostriatal system plays a role in depressive-like behaviors, whilst animal models of PD are employed. Therefore, we addressed the question of whether dopamine (DA) depletion, promoted by the neurotoxins 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), 6-hydroxydopamine (6-OHDA), lipopolysaccharide (LPS) and rotenone are able to induce depressive-like behaviors and neurotransmitters alterations similarly that encountered in PD. To test this rationale, we performed intranigral injections of each neurotoxin, followed by motor behavior, depressive-like behaviors, histological and neurochemical tests. After the motor recovery period, MPTP, 6-OHDA and rotenone were able to produce anhedonia and behavioral despair. These altered behavioral responses were accompanied by reductions of striatal DA, homovanillic acid (HVA) and 3,4-dihydroxyphenylacetic acid (DOPAC) restricted to the 6-OHDA group. Additionally, decreases on the hippocampal serotonin (5-HT) content were detected for the MPTP, 6-OHDA and rotenone groups. Notably, strong correlations were detected among the groups when 5-HT and DA were correlated with swimming (r=+0.97; P=0.001) and immobility (r=-0.90; P=0.012), respectively. Our data indicate that MPTP, 6-OHDA and rotenone, but not LPS were able to produce depressive-like behaviors accompanied primarily by hippocampal 5-HT reductions. Moreover, DA and 5-HT strongly correlated with "emotional" impairments suggesting an important participation of these neurotransmitters in anhedonia and behavioral despair after nigral lesions promoted by the neurotoxins. PMID:20547199

  12. TACC3 depletion sensitizes to paclitaxel-induced cell death and overrides p21WAF-mediated cell cycle arrest.

    PubMed

    Schneider, L; Essmann, F; Kletke, A; Rio, P; Hanenberg, H; Schulze-Osthoff, K; Nürnberg, B; Piekorz, R P

    2008-01-01

    Regulators of the mitotic spindle apparatus are attractive cellular targets for antitumor therapy. The centrosomal protein transforming acidic coiled coil (TACC) 3 is required for spindle assembly and proper chromosome segregation. In this study, we employed an inducible RNA interference approach to downregulate TACC3 expression. We show that TACC3 knock-down in NIH3T3 fibroblasts caused aneuploidy, but failed to overtly impair mitotic progression. TACC3 depletion rather triggered a postmitotic p53-p21(WAF) pathway and led to a reversible cell cycle arrest. Similar effects were induced by low concentrations of paclitaxel, a spindle poison used in antitumor therapy. Interestingly, however, and unlike in TACC3-proficient cells, paclitaxel was able to induce strong polyploidy and subsequent apoptosis in TACC3-depleted cells. Even though paclitaxel treatment was associated with the activation of the survival kinase Akt and an antiapoptotic expression of cytoplasmic p21(WAF) and cyclin D1, this inhibition of cell death was abrogated by depletion of TACC3. Thus, our data identify TACC3 as a potential target to overcome p21(WAF)-associated protection of transformed cells against paclitaxel-induced cell death. PMID:17599038

  13. Decreased ER-associated degradation of ?-TCR induced by Grp78 depletion with the SubAB cytotoxin

    PubMed Central

    Lass, Agnieszka; Kujawa, Marek; McConnell, Elizabeth; Paton, Adrienne W.; Paton, James C.; Wjcik, Cezary

    2008-01-01

    HeLa cells stably expressing the ? chain of T-cell receptor (?TCR), a model substrate of ERAD (ER-associated degradation), were used to analyze the effects of BiP/Grp78 depletion by the SubAB cytotoxin. SubAB induced XBP1 splicing, followed by JNK phosphorylation, eIF2? phosphorylation, upregulation of ATF3/4 and partial ATF6 cleavage. Other markers of ER stress, including elements of ER-associated degradation (ERAD) pathway, as well as markers of cytoplasmic stress, were not induced. SubAB treatment decreased absolute levels of ?TCR, which was caused by inhibition of protein synthesis. At the same time, the half-life of ?TCR was extended almost fourfold from 70 min to 210 min, suggesting that BiP normally facilitates ERAD. Depletion ofp97/VCP partially rescued SubAB-induced depletion of ?TCR, confirming the role of VCP in ERAD of ?TCR. It therefore appears that ERAD of ?TCR is driven by at least two different ATP-ase systems located at two sides of the ER membrane, BiP located on the lumenal side, while p97/VCP on the cytoplasmic side. While SubAB altered cell morphology by inducing cytoplasm vacuolization and accumulation of lipid droplets, caspase activation was partial and subsided after prolonged incubation. Expression of CHOP/GADD153 occurred only after prolonged incubation and was not associated with apoptosis. PMID:18611445

  14. Cue-induced striatal dopamine release in Parkinson's disease-associated impulsive-compulsive behaviours.

    PubMed

    O'Sullivan, Sean S; Wu, Kit; Politis, Marios; Lawrence, Andrew D; Evans, Andrew H; Bose, Subrata K; Djamshidian, Atbin; Lees, Andrew J; Piccini, Paola

    2011-04-01

    Impulsive-compulsive behaviours are a significant source of morbidity for patients with Parkinson's disease receiving dopaminergic therapy. The development of these behaviours may reflect sensitization of the neural response to non-drug rewards, similar to that proposed for sensitization to drug rewards in addiction. Here, by using (11)C-raclopride positron emission tomography imaging, we investigated the effects of reward-related cues and L-dopa challenge in patients with Parkinson's disease with and without impulsive-compulsive behaviours on striatal levels of synaptic dopamine. Eighteen patients (11 with and seven without impulsive-compulsive behaviours) underwent three (11)C-raclopride positron emission tomography scans. The impulsive-compulsive behaviours included hypersexuality, binge eating, punding, compulsive use of dopamine replacement therapy, compulsive buying and pathological gambling, with eight patients exhibiting more than one impulsive-compulsive behaviour. There were no significant differences in baseline dopamine D2 receptor availability between the Parkinson's disease groups. No differences were found when comparing the percentage change of raclopride binding potential between the two Parkinson's disease groups following L-dopa challenge with neutral cues. The group with Parkinson's disease with impulsive-compulsive behaviours had a greater reduction of ventral striatum (11)C-raclopride binding potential following reward-related cue exposure, relative to neutral cue exposure, following L-dopa challenge (16.3% compared with 5.8% in Parkinson's disease controls, P?=?0.016). The heightened response of striatal reward circuitry to heterogeneous reward-related visual cues among a group of patients with different impulsive-compulsive behaviours is consistent with a global sensitization to appetitive behaviours with dopaminergic therapy in vulnerable individuals. Our findings are relevant for the broader debate on the relation between impulsive-compulsive behaviours and addictions and may have important implications with regards to advertisement legislation in an effort to prevent the onset of behavioural addictions. PMID:21349901

  15. Age dependence of myosin heavy chain transitions induced by creatine depletion in rat skeletal muscle

    NASA Technical Reports Server (NTRS)

    Adams, Gregory R.; Baldwin, Kenneth M.

    1995-01-01

    This study was designed to test the hypothesis that myosin heavy chain (MHC) plasticity resulting from creatine depletion is an age-dependent process. At weaning (age 28 days), rat pups were placed on either standard rat chow (normal diet juvenile group) or the same chow supplemented with 1% wt/wt of the creatine analogue beta-guanidinopropionic acid (creatine depletion juvenile (CDJ) group). Two groups of adult rats (age approximately 8 wk) were placed on the same diet regimens (normal diet adult and creatine depletion adult (CDA) groups). After 40 days (CDJ and normal diet juvenile groups) and 60 days (CDA and normal diet adult groups), animals were killed and several skeletal muscles were removed for analysis of creatine content or MHC ditribution. In the CDJ group, creatine depletion (78%) was accompanied by significant shifts toward expression of slower MHC isoforms in two slow and three fast skeletal muscles. In contrast, creatine depletion in adult animals did not result in similar shifts toward slow MHC isoform expression in either muscle type. The results of this study indicate that there is a differential effect of creatine depletion on MHC tranitions that appears to be age dependent. These results strongly suggest that investigators contemplating experimental designs involving the use of the creatine analogue beta-guanidinopropionic acid should consider the age of the animals to be used.

  16. Psychostimulants affect dopamine transmission through both dopamine transporter-dependent and independent mechanisms.

    PubMed

    dela Pea, Ike; Gevorkiana, Ruzanna; Shi, Wei-Xing

    2015-10-01

    The precise mechanisms by which cocaine and amphetamine-like psychostimulants exert their reinforcing effects are not yet fully defined. It is widely believed, however, that these drugs produce their effects by enhancing dopamine neurotransmission in the brain, especially in limbic areas such as the nucleus accumbens, by inducing dopamine transporter-mediated reverse transport and/or blocking dopamine reuptake though the dopamine transporter. Here, we present the evidence that aside from dopamine transporter, non-dopamine transporter-mediated mechanisms also participate in psychostimulant-induced dopamine release and contribute to the behavioral effects of these drugs, such as locomotor activation and reward. Accordingly, psychostimulants could increase norepinephrine release in the prefrontal cortex, the latter then alters the firing pattern of dopamine neurons resulting in changes in action potential-dependent dopamine release. These alterations would further affect the temporal pattern of dopamine release in the nucleus accumbens, thereby modifying information processing in that area. Hence, a synaptic input to a nucleus accumbens neuron may be enhanced or inhibited by dopamine depending on its temporal relationship to dopamine release. Specific temporal patterns of dopamine release may also be required for certain forms of synaptic plasticity in the nucleus accumbens. Together, these effects induced by psychostimulants, mediated through a non-dopamine transporter-mediated mechanism involving norepinephrine and the prefrontal cortex, may also contribute importantly to the reinforcing properties of these drugs. PMID:26209364

  17. Activation of striatal group II metabotropic glutamate receptors has a differential effect on dopamine-D1 and -D2 receptor antagonist-induced hypokinesia in the rat.

    PubMed

    Kronthaler, U O; Schmidt, W J

    2000-03-01

    Motor function of group II metabotropic glutamate receptors was investigated by quantifying motor effects of bilateral infusions of the preferential group II metabotropic glutamate receptor agonist (2S,3S,4S)-alpha-carboxycyclopropyl-glycine (15, 30, 60 nmol/0.5 microl) into the striatum of conscious rats. (2S,3S,4S)-alpha-carboxycyclopropyl-glycine reduced spontaneous sniffing activity in an experimental chamber, but did not affect spontaneous locomotor (line crossings) or exploratory behaviour (rearings, hole visits) in an open field equipped with a hole-board. Intrastriatal infusion of the selective group III metabotropic glutamate receptor agonist L-2-amino-4-phosphobutyric acid (15, 30, 60, 120 nmol/0.5 microl) did not influence spontaneous motor behaviour. Intrastriatal infusion of (2S,3S,4S)-alpha-carboxycyclopropyl-glycine (15 nmol/0.5 microl and 30 nmol/0.5 microl) further depressed spontaneous motor behaviour in rats pretreated with the dopamine-D1 receptor antagonist (-)-trans-6,7,7a,8,9,13b-hexahydro-3-chloro-2-hydroxy-N-methyl-5H- benzo[d]naphtho-(2,1-b)azepine, but not if rats were pretreated with the preferential dopamine-D2 receptor antagonist haloperidol. It appears likely that the depression of spontaneous motor behaviour evoked by the preferential group II agonist (2S,3S,4S)-alpha-carboxycyclopropyl-glycine is mediated by activation of group II metabotropic glutamate receptors, since activation of group I metabotropic glutamate receptors has been shown to stimulate motor behaviour, and activation of group III metabotropic glutamate receptors had no effect, as shown in this study. Therefore, it is reasonable to speculate that the striatum may contribute to the motor-depressant effects of systemically applied group II metabotropic glutamate receptor agonists, as reported by us recently. The present findings further suggest that a functional dopamine-D1 antagonism contributes to the motor effects of group II metabotropic glutamate receptor agonists. PMID:10731042

  18. Rapid substrate-induced down-regulation in function and surface localization of dopamine transporters: rat dorsal striatum versus nucleus accumbens

    PubMed Central

    Richards, Toni L.; Zahniser, Nancy R.

    2010-01-01

    The dopamine transporter (DAT) substrates dopamine, d-amphetamine (AMPH), and methamphetamine are known to rapidly and transiently reduce DAT activity and/or surface expression in dorsal striatum and heterologous expression systems. We sought to determine if similar substrate-induced regulation of DATs occurs in rat nucleus accumbens. In dorsal striatum synaptosomes, brief (15-min) in vitro substrate pre-exposure markedly decreased maximal [3H]dopamine uptake velocity whereas identical substrate pre-exposure in nucleus accumbens synaptosomes produced a smaller, non-significant reduction. However, 45 min after systemic AMPH administration, maximal ex vivo [3H]dopamine uptake velocity was significantly reduced in both brain regions. Protein kinase C inhibition blocked AMPHs down-regulation of DAT activity. DAT synaptosomal surface expression was not modified following either the brief in vitro or in vivo AMPH pre-exposure but was reduced after a longer (1-h) in vitro pre-exposure in both brain regions. Together, our findings suggest that relatively brief substrate exposure results in greater down-regulation of DAT activity in dorsal striatum than in nucleus accumbens. Moreover, exposure to AMPH appears to regulate striatal dopamine transporters in a biphasic manner, with an initial protein kinase C-dependent decrease in DAT-mediated uptake velocity and then, with longer exposure, a reduction in DAT expression. PMID:19183252

  19. On the signal depletion induced by stretching excitation of methane in the reaction with the F atom.

    PubMed

    Cheng, Yuan; Pan, Huilin; Wang, Fengyan; Liu, Kopin

    2014-01-14

    Exciting a stretching mode of a chemical bond should help its breaking during a chemical reaction, according to conventional wisdom. In several recent studies of the reactions of stretch-excited methane (and isotopologues) with the F atom, counterintuitively, we found that the induced reactant vibrations instead inhibit the bond rupture and slow down the overall reaction rate. This intriguing observation has been qualitatively ascribed to the vibrationally induced steric effects of the reaction in previous reports. However, quantitative determination of the reactivity suppression in terms of reaction cross sections remains lacking. In this report, we scrutinize the physical meaning of this (product) signal depletion phenomenon and fill the gap. Through a systematic investigation we further elucidate the additional reaction dynamics information that can be retrieved from the depletion measurements. The resultant rotationally state-selected reaction cross sections for both the vibrational ground and excited states are presented, and the stereodynamical implications are delineated. PMID:24048150

  20. Kappa opioid receptor activation potentiates the cocaine-induced increase in evoked dopamine release recorded in vivo in the mouse nucleus accumbens.

    PubMed

    Ehrich, Jonathan M; Phillips, Paul E M; Chavkin, Charles

    2014-12-01

    Behavioral stressors increase addiction risk in humans and increase the rewarding valence of drugs of abuse including cocaine, nicotine and ethanol in animal models. Prior studies have established that this potentiation of drug reward was mediated by stress-induced release of the endogenous dynorphin opioids and subsequent kappa opioid receptor (KOR) activation. In this study, we used in vivo fast scan cyclic voltammetry to test the hypothesis that KOR activation before cocaine administration might potentiate the evoked release of dopamine from ventral tegmental (VTA) synaptic inputs to the nucleus accumbens (NAc) and thereby increase the rewarding valence of cocaine. The KOR agonist U50488 inhibited dopamine release evoked by either medial forebrain bundle (MFB) or pedunculopontine tegmental nucleus (PPTg) activation of VTA inputs to the shell or core of the mouse NAc. Cocaine administration increased the dopamine response recorded in either the shell or core evoked by either MFB or PPTg stimulation. Administration of U50488 15 min before cocaine blocked the conditioned place preference (CPP) to cocaine, but only significantly reduced the effect of cocaine on the dopamine response evoked by PPTg stimulation to NAc core. In contrast, administration of U50488 60 min before cocaine significantly potentiated cocaine CPP and significantly increased the effects of cocaine on the dopamine response evoked by either MFB or PPTg stimulation, recorded in either NAc shell or core. Results of this study support the concept that stress-induced activation of KOR by endogenous dynorphin opioids may enhance the rewarding valence of drugs of abuse by potentiating the evoked dopamine response. PMID:24971603

  1. Selective Deletion of GRK2 Alters Psychostimulant-Induced Behaviors and Dopamine Neurotransmission

    PubMed Central

    Daigle, Tanya L; Ferris, Mark J; Gainetdinov, Raul R; Sotnikova, Tatyana D; Urs, Nikhil M; Jones, Sara R; Caron, Marc G

    2014-01-01

    GRK2 is a G protein-coupled receptor kinase (GRK) that is broadly expressed and is known to regulate diverse types of receptors. GRK2 null animals exhibit embryonic lethality due to a severe developmental heart defect, which has precluded the study of this kinase in the adult brain. To elucidate the specific role of GRK2 in the brain dopamine (DA) system, we used a conditional gene knockout approach to selectively delete GRK2 in DA D1 receptor (D1R)-, DA D2 receptor (D2R)-, adenosine 2A receptor (A2AR)-, or DA transporter (DAT)-expressing neurons. Here we show that select GRK2-deficient mice display hyperactivity, hyposensitivity, or hypersensitivity to the psychomotor effects of cocaine, altered striatal signaling, and DA release and uptake. Mice with GRK2 deficiency in D2R-expressing neurons also exhibited increased D2 autoreceptor activity. These findings reveal a cell-type-specific role for GRK2 in the regulation of normal motor behavior, sensitivity to psychostimulants, dopamine neurotransmission, and D2 autoreceptor function. PMID:24776686

  2. Music and Methamphetamine: Conditioned Cue-induced Increases in Locomotor Activity and Dopamine Release in Rats

    PubMed Central

    Polston, J.E.; Rubbinaccio, H.Y.; Morra, J.T.; Sell, E.M.; Glick, S.D.

    2011-01-01

    Associations between drugs of abuse and cues facilitate the acquisition and maintenance of addictive behaviors. Although significant research has been done to elucidate the role that simple discriminative or discrete conditioned stimuli (e.g., a tone or a light) play in addiction, less is known about complex environmental cues. The purpose of the present study was to examine the role of a musical conditioned stimulus by assessing locomotor activity and in vivo microdialysis. Two groups of rats were given non-contingent injections of methamphetamine (1.0 mg/kg) or vehicle and placed in standard conditioning chambers. During these conditioning sessions both groups were exposed to a continuous conditioned stimulus, in the form of a musical selection (“Four” by Miles Davis) played repeatedly for ninety minutes. After seven consecutive conditioning days subjects were given one day of rest, and subsequently tested for locomotor activity or dopamine release in the absence of drug while the musical conditioned stimulus was continually present. The brain regions examined included the basolateral amygdala, nucleus accumbens, and prefrontal cortex. The results show that music is an effective contextual conditioned stimulus, significantly increasing locomotor activity after repeated association with methamphetamine. Furthermore, this musical conditioned stimulus significantly increased extracellular dopamine levels in the basolateral amygdala and nucleus accumbens. These findings support other evidence showing the importance of these brain regions in conditioned learning paradigms, and demonstrate that music is an effective conditioned stimulus warranting further investigation. PMID:21145911

  3. Selective deletion of GRK2 alters psychostimulant-induced behaviors and dopamine neurotransmission.

    PubMed

    Daigle, Tanya L; Ferris, Mark J; Gainetdinov, Raul R; Sotnikova, Tatyana D; Urs, Nikhil M; Jones, Sara R; Caron, Marc G

    2014-09-01

    GRK2 is a G protein-coupled receptor kinase (GRK) that is broadly expressed and is known to regulate diverse types of receptors. GRK2 null animals exhibit embryonic lethality due to a severe developmental heart defect, which has precluded the study of this kinase in the adult brain. To elucidate the specific role of GRK2 in the brain dopamine (DA) system, we used a conditional gene knockout approach to selectively delete GRK2 in DA D1 receptor (D1R)-, DA D2 receptor (D2R)-, adenosine 2A receptor (A2AR)-, or DA transporter (DAT)-expressing neurons. Here we show that select GRK2-deficient mice display hyperactivity, hyposensitivity, or hypersensitivity to the psychomotor effects of cocaine, altered striatal signaling, and DA release and uptake. Mice with GRK2 deficiency in D2R-expressing neurons also exhibited increased D2 autoreceptor activity. These findings reveal a cell-type-specific role for GRK2 in the regulation of normal motor behavior, sensitivity to psychostimulants, dopamine neurotransmission, and D2 autoreceptor function. PMID:24776686

  4. Music and methamphetamine: conditioned cue-induced increases in locomotor activity and dopamine release in rats.

    PubMed

    Polston, J E; Rubbinaccio, H Y; Morra, J T; Sell, E M; Glick, S D

    2011-03-01

    Associations between drugs of abuse and cues facilitate the acquisition and maintenance of addictive behaviors. Although significant research has been done to elucidate the role that simple discriminative or discrete conditioned stimuli (e.g., a tone or a light) play in addiction, less is known about complex environmental cues. The purpose of the present study was to examine the role of a musical conditioned stimulus by assessing locomotor activity and in vivo microdialysis. Two groups of rats were given non-contingent injections of methamphetamine (1.0 mg/kg) or vehicle and placed in standard conditioning chambers. During these conditioning sessions both groups were exposed to a continuous conditioned stimulus, in the form of a musical selection ("Four" by Miles Davis) played repeatedly for 90 min. After seven consecutive conditioning days subjects were given one day of rest, and subsequently tested for locomotor activity or dopamine release in the absence of drugs while the musical conditioned stimulus was continually present. The brain regions examined included the basolateral amygdala, nucleus accumbens, and prefrontal cortex. The results show that music is an effective contextual conditioned stimulus, significantly increasing locomotor activity after repeated association with methamphetamine. Furthermore, this musical conditioned stimulus significantly increased extracellular dopamine levels in the basolateral amygdala and nucleus accumbens. These findings support other evidence showing the importance of these brain regions in conditioned learning paradigms, and demonstrate that music is an effective conditioned stimulus warranting further investigation. PMID:21145911

  5. ?-Lipoic Acid Induced Elevated S-adenosylhomocysteine and Depleted S-adenosylmethionine

    PubMed Central

    Stabler, Sally P.; Sekhar, Jeevan; Allen, Robert H.; O'Neill, Heidi C.; White, Carl W.

    2009-01-01

    Lipoic Acid is a disulfhydryl-containing compound used in clinical medicine and in experimental models as an antioxidant. We developed a stable isotope dilution capillary gas chromatography/mass spectrometry assay for lipoic acid. We assayed a panel of the metabolites of transmethylation and transsulfuration 30 minutes after injecting lipoic acid 100 mg/kg in a rat model. Lipoic acid values rose 1000-fold in serum and 10-fold in liver. A methylated metabolite of lipoic acid was also detected but not quantitated. Lipoic acid injection caused a massive increase in serum S-adenosylhomocysteine and marked depletion of liver S-adenosylmethionine. Serum total cysteine was depleted but liver cysteine and glutathione were maintained. Serum total homocysteine doubled with increases also in cystathionine, N, N-dimethylglycine and alpha-aminobutyric acid. In contrast, after injection of 2-mercaptoethanesulfonic acid (MESNA), serum total cysteine and homocysteine were markedly depleted and there were no effects on serum S-adenosylmethionine or S-adenosylhomocysteine. We conclude that large doses of lipoic acid both displace sulfhydryls from binding sites resulting in depletion of serum cysteine but also pose a methylation burden with severe depletion of liver S-adenosylmethionine and massive release of S-adenosylhomocysteine. These changes may have previously unrecognized deleterious effects that should be investigated in both human disease and experimental models. PMID:19616616

  6. The dopamine D3 receptor regulates the effects of methamphetamine on LPS-induced cytokine production in murine mast cells.

    PubMed

    Xue, Li; Li, Xia; Ren, Hui-Xun; Wu, Feng; Li, Ming; Wang, Biao; Chen, Fang-Yuan; Cheng, Wei-Ying; Li, Ju-Ping; Chen, Yan-Jiong; Chen, Teng

    2015-06-01

    Previous studies have demonstrated that methamphetamine (METH) alter inflammatory and anti-inflammatory cytokine production in the periphery. However, the effect of METH on lipopolysaccharide (LPS)-induced immune responses and its underlying mechanism of action remains unclear. The dopamine D3 receptor (D3R) plays an important role in METH addiction, indicating that the D3R may regulate METH-mediated immune responses. In this study, we examined the effect of METH on mast cell released cytokines in the lungs and thymi of mice stimulated by LPS, and on LPS-induced murine bone marrow-derived mast cells (BMMCs). Moreover, we used D3R-deficient mice to investigate the effect of this receptor on LPS-stimulated mast cell released cytokine production after METH treatment in the lungs and thymi. The effects of a D3R agonist and antagonist on LPS-induced cytokine production after METH treatment in murine BMMCs were also evaluated. METH suppressed LPS-induced cytokine production in the lungs and thymi of wild-type (WT) mice and BMMCs. However, METH did not alter LPS-induced cytokine production in the lungs and thymi of D3R-deficient mice. When BMMCs were treated with the D3R receptor antagonist, NGB2904 hydrochloride (NGB-2904), METH did not alter LPS-induced cytokine production. However, treatment with the D3R agonist, 7-hydroxy-(di-n-propylamino) tetralin (7-OH-DPAT), significantly enhanced the effects of METH on LPS-induced cytokine production. Our results suggest that METH regulates mast cell released cytokines production in an LPS-induced mouse model via the D3R. PMID:25601390

  7. L-stepholidine, a natural dopamine receptor D1 agonist and D2 antagonist, inhibits heroin-induced reinstatement.

    PubMed

    Ma, Baomiao; Yue, Kai; Chen, Lin; Tian, Xiang; Ru, Qin; Gan, Yongping; Wang, Daisong; Jin, Guozhang; Li, Chaoying

    2014-01-24

    L-Stepholidine (l-SPD), an alkaloid extract of the Chinese herb Stephania intermedia, is the first compound known to exhibit mixed dopamine D1 receptor agonist/D2 antagonist properties and is a potential medication for the treatment of opiate addiction. The aim of the present study was to investigate the effects of pretreatment with L-SPD on heroin-seeking behavior induced by heroin priming. Male Sprague-Dawley rats were trained to self-administer heroin (0.05mg/kg per infusion) under a fixed ratio 1 schedule for 12 consecutive days and nose-poke responding was extinguished for 12 days, after which reinstatement of drug seeking was induced by heroin priming. Pretreatment with L-SPD (2.5, 5.0 and 10.0mg/kg, i.p.) inhibited the heroin-induced reinstatement of heroin-seeking behavior. Importantly, L-SPD did not affect locomotion, indicating that the observed effects of L-SPD on reinstatement are not the result of motor impairments. The present data suggested that l-SPD inhibits heroin-induced reinstatement and its potential for the treatment of heroin relapse. PMID:24269875

  8. The galanin receptor agonist, galnon, attenuates cocaine-induced reinstatement and dopamine overflow in the frontal cortex.

    PubMed

    Ogbonmwan, Yvonne E; Sciolino, Natale R; Groves-Chapman, Jessica L; Freeman, Kimberly G; Schroeder, Jason P; Edwards, Gaylen L; Holmes, Philip V; Weinshenker, David

    2015-07-01

    Relapse represents one of the most significant problems in the long-term treatment of drug addiction. Cocaine blocks plasma membrane monoamine transporters and increases dopamine (DA) overflow in the brain, and DA is critical for the motivational and primary reinforcing effects of the drug as well as cocaine-primed reinstatement of cocaine seeking in rats, a model of relapse. Thus, modulators of the DA system may be effective for the treatment of cocaine dependence. The endogenous neuropeptide galanin inhibits DA transmission, and both galanin and the synthetic galanin receptor agonist, galnon, interfere with some rewarding properties of cocaine. The purpose of this study was to further assess the effects of galnon on cocaine-induced behaviors and neurochemistry in rats. We found that galnon attenuated cocaine-induced motor activity, reinstatement and DA overflow in the frontal cortex at a dose that did not reduce baseline motor activity, stable self-administration of cocaine, baseline extracellular DA levels or cocaine-induced DA overflow in the nucleus accumbens (NAc). Similar to cocaine, galnon had no effect on stable food self-administration but reduced food-primed reinstatement. These results indicate that galnon can diminish cocaine-induced hyperactivity and relapse-like behavior, possibly in part by modulating DA transmission in the frontal cortex. PMID:25053279

  9. A77 1726 induces differentiation of human myeloid leukemia K562 cells by depletion of intracellular CTP pools.

    PubMed

    Huang, Min; Wang, Yanhong; Collins, Matthew; Mitchell, Beverly S; Graves, Lee M

    2002-09-01

    A77 1726 (LEF) is the active metabolite of leflunomide, a recently approved immunosuppressive agent. We examined the ability of LEF to induce differentiation of a human erythroleukemia (K562) cell line and show that LEF induces a dose- and time-dependent differentiation of these cells as characterized by growth inhibition, hemoglobin production, and erythroid membrane protein glycophorin A expression. This effect was dependent on depletion of the intracellular pyrimidine ribonucleotides (UTP and CTP), and preceded by a specific S-phase arrest of the cell cycle. Supplementation of the cultures with exogenous uridine restored intracellular UTP and CTP to normal levels and prevented the LEF-induced cell cycle block and differentiation of K562 cells. Interestingly, addition of cytidine alone blocked the LEF-induced differentiation of K562 cells but only restored the CTP pool. By contrast, neither deoxycytidine nor thymidine prevented the effects of LEF on these cells. Similarly, pyrimidine starvation of a cell line lacking the de novo pyrimidine pathway (G9c) resulted in an S-phase arrest that was reversed by the addition of cytidine. Thus these studies demonstrate an important role for CTP in regulating cell cycle progression and show that LEF is an effective inducer of tumor cell differentiation through depletion of this ribonucleotide. PMID:12181422

  10. Dopamine D3 Receptor Mediates Preadolescent Stress-Induced Adult Psychiatric Disorders

    PubMed Central

    Seo, Joon H.; Kuzhikandathil, Eldo V.

    2015-01-01

    Several studies have shown that repeated stressful experiences during childhood increases the likelihood of developing depression- and anxiety-related disorders in adulthood; however, the underlying mechanisms are not well understood. We subjected drd3-EGFP and drd3-null mice to daily, two hour restraint stress episodes over a five day period during preadolescence (postnatal day 35 to 39), followed by social isolation. When these mice reached adulthood (post-natal day > 90), we assessed locomotor behavior in a novel environment, and assessed depression-related behavior in the Porsolt Forced Swim test. We also measured the expression and function of dopamine D3 receptor in limbic brain areas such as hippocampus, nucleus accumbens and amygdala in control and stressed drd3-EGFP mice in adulthood. Adult male mice subjected to restraint stress during preadolescence exhibited both anxiety- and depression-related behaviors; however, adult female mice subjected to preadolescent restraint stress exhibited only depression-related behaviors. The development of preadolescent stress-derived psychiatric disorders was blocked by D3 receptor selective antagonist, SB 277011-A, and absent in D3 receptor null mice. Adult male mice that experienced stress during preadolescence exhibited a loss of D3 receptor expression and function in the amygdala but not in hippocampus or nucleus accumbens. In contrast, adult female mice that experienced preadolescent stress exhibited increased D3 receptor expression in the nucleus accumbens but not in amygdala or hippocampus. Our results suggest that the dopamine D3 receptor is centrally involved in the etiology of adult anxiety- and depression-related behaviors that arise from repeated stressful experiences during childhood. PMID:26619275

  11. Mitochondria are an essential mediator of nitric oxide/cyclic guanosine 3',5'-monophosphate blocking of glucose depletion induced cytotoxicity in human HepG2 cells.

    PubMed

    Hsu, Yi-Chiung; Lee, Hsin-Chen; Ping, Yueh-Hsin; Liu, Tsung-Yun; Lui, Wing-Yiu; Chi, Chin-Wen

    2007-09-01

    It is well known that glucose is a major energy source in tumors and that mitochondria are specialized organelles required for energy metabolism. Previous studies have revealed that nitric oxide (NO) protects against glucose depletion-induced cytotoxicity in mouse liver cells and in rat hepatocytes, but the detailed mechanism is not well understood. Therefore, we investigated the involvement of mitochondria in the NO protective effect in human hepatoma HepG2 cells. In this study, we showed that glucose depletion resulted in a time-dependent decrease in intracellular NO and in the protein expression of NO synthases. This glucose depletion-induced decrease in NO was blocked by NO donors. Next, we showed that the cytoprotective effect of NO is via a cyclic guanosine 3',5'-monophosphate-dependent pathway. Additionally, SNP blocked a glucose depletion-induced decrease in mitochondrial mass, mitochondrial DNA copies, and ATP level in HepG2 cells. Moreover, glucose depletion decreased the expression of various mitochondrial proteins, including cytochrome c, complex I (NADH dehydrogenase), complex III (cytochrome c reductase), and heat shock protein 60; these glucose depletion-induced effects were blocked by SNP. Furthermore, we found that rotenone and antimycin A (mitochondria complex I and III inhibitors, respectively) blocked SNP cytoprotection against glucose depletion-induced cytotoxicity. Taken together, our results indicated that the mitochondria serve as an important cellular mediator of NO during protection against glucose deprivation-induced damage. PMID:17855661

  12. Bimodal effects of dopamine D2 receptor agonists on zero Mg(2+)-induced epileptiform activity in the rat cingulate cortex slice.

    PubMed

    Alam, A M; Starr, M S

    1994-01-01

    A previous study demonstrated a dopamine D1 receptor-dependent inhibition of zero Mg(2+)-induced epileptiform discharges in the rat cingulate cortex slice suspended in a grease-gap bath. This investigation considers the role of dopamine D2 receptors in the modulation of paroxysmal activity in this in vitro model. Some 123 of 143 slices exhibited spontaneous paroxysmal depolarizations, which in 105 cases were accompanied by secondary depolarizing after-potentials (SDAPs). In 43.5% of slices tested, dopamine preferentially and irreversibly facilitated SDAP production at low bath concentrations (1-100 microM), but at concentrations > 100 microM suppressed all components of the epileptiform responses. Similar dose-related bimodal responses were obtained with the D2 agonists LY 171555, PHNO and 7-OH-DPAT, but not with lisuride or RU 24213, which were exclusively inhibitory. The excitatory response to LY 171555 was attenuated by the D2 antagonist raclopride (2 microM), but not by the D1 antagonist SCH 39166 (0.5 microM). On the other occasions, the sole effect of dopamine (56.5% of slices) and the other D2 agonists, was to preferentially suppress SDAP number at low concentrations (1-100 microM) and to suppress all parameters of the epileptiform response at higher concentrations. The inhibitory effect of the D2 agonist LY 171555 on SDAP formation was paradoxically attenuated by the D1 antagonist SCH 39166, but not by the D2 antagonist raclopride. These results support the notion that dopamine can modulate epileptiform activity differentially, through its actions at D1 and D2 receptors. The possibility that these effects of dopamine may be mediated indirectly is discussed. PMID:7895801

  13. On the possible fault activation induced by UGS in depleted reservoirs

    NASA Astrophysics Data System (ADS)

    Feronato, Massimiliano; Gambolati, Giuseppe; Janna, Carlo; Teatini, Pietro; Tosattto, Omar

    2014-05-01

    Underground gas storage (UGS) represents an increasingly used approach to cope with the growing energy demand and occurs in many countries worldwide. Gas is injected in previously depleted deep reservoirs during summer when consumption is limited and removed in cold season mainly for heating. As a major consequence the pore pressure p within a UGS reservoir fluctuates yearly between a maximum close to the value pi prior to the field development and a minimum usually larger than the lowest pressure experienced by the reservoir at the end of its production life. The high frequency pressure fluctuations generally confine the pressure change volume to the reservoir volume without significantly involving the aquifers hydraulically connected to the hydrocarbon field (lateral and/or bottom waterdrive). The risk of UGS-induced seismicity is therefore restricted to those cases where existing faults cross or bound the reservoir. The possible risk of anthropogenic seismicity due to UGS operations is preliminary investigated by an advanced Finite Element (FE) - Interface Element (IE) 3-D elasto-plastic geomechanical model in a representative 1500 m deep reservoir bounded by a regional sealing fault and compartimentalized by an internal non-sealing thrust. Gas storage/production is ongoing with p ranging between pi in October/November and 60%pi in April/May. The yearly pressure fluctuation is assumed to be on the order of 50 bar. The overall geomechanical response of the porous medium has been calibrated by reproducing the vertical and horizontal cyclic displacements measured above the reservoir by advanced persistent scatterer interferometry. The FE-IE model shows that the stress variations remain basically confined within the gas field and negligibly propagate within the caprock and the waterdrive. Based on the Mohr-Coulomb failure criterion, IEs allow for the prediction of the fault activated area A, located at the reservoir depth as expected, and slip displacement d. A number of parametric scenarios are investigated to address the major uncertainties on the geomechanical fault properties, i.e., cohesion c and friction angle φ of the fault materials, and the initial stress regime (passive or compressive basin). The magnitude M of potential seismic events induced by the fault reactivation is evaluated by an empirical relation derived from seismological theories. M turns out to be correlated to the activated volume A × d and the shear modulus G of the host rock. With G = 3.9 × 104 bar, as provided by the calibration of the geomechanical model, the results point out that M may peak up to around 1 in the most conservative scenario, i.e. c = 0 bar, φ = 30°, entirely instantaneous slip and a passive stress basin. With c = 10 bar, a plausible value for the investigated reservoir, the fault does not activate. Under the above conditions fault activation by UGS does not appear to be a matter of concern.

  14. UV Radiation Induces the Epidermal Recruitment of Dendritic Cells that Compensate for the Depletion of Langerhans Cells in Human Skin.

    PubMed

    Achachi, Amine; Vocanson, Marc; Bastien, Philippe; Pguet-Navarro, Josette; Grande, Sophie; Goujon, Catherine; Breton, Lionel; Castiel-Higounenc, Isabelle; Nicolas, Jean-Franois; Gueniche, Audrey

    2015-08-01

    UVR causes skin injury and inflammation, resulting in impaired immune function and increased skin cancer risk. Langerhans cells (LCs), the immune sentinels of the epidermis, are depleted for several days following a single UVR exposure and can be reconstituted from circulating monocytes. However, the differentiation pathways leading to the recovery of a normal pool of LCs is still unclear. To study the dynamic changes in human skin with UV injury, we exposed a cohort of 29 healthy human volunteers to a clinically relevant dose of UVR and analyzed sequential epidermal biopsies for changes in leukocyte and dendritic cell (DC) subsets. UV-induced depletion of CD1a(high) LC was compensated by sequential appearance of various epidermal leukocytes. CD14(+) monocytes were recruited as early as D1 post exposure, followed by recruitment of two inflammatory DC subsets that may represent precursors of LCs. These CD1a(low) CD207(-) and the heretofore unknown CD1a(low) CD207(+) DCs appeared at day 1 and day 4 post UVR, respectively, and were endowed with T-cell-activating properties similar to those of LCs. We conclude that recruitment of monocytes and inflammatory DCs appear as a physiological response of the epidermis in order to repair UVR-induced LC depletion associated with immune suppression. PMID:25806853

  15. Depletion of HDAC6 Enhances Cisplatin-Induced DNA Damage and Apoptosis in Non-Small Cell Lung Cancer Cells

    PubMed Central

    Williams, Kendra A.; Dong, Huiqin; Bai, Wenlong; Nicosia, Santo V.; Khochbin, Saadi; Bepler, Gerold; Zhang, Xiaohong

    2012-01-01

    Histone deacetylase inhibitors (HDACi) are promising therapeutic agents which are currently used in combination with chemotherapeutic agents in clinical trials for cancer treatment including non-small cell lung cancer (NSCLC). However, the mechanisms underlying their anti-tumor activities remain elusive. Previous studies showed that inhibition of HDAC6 induces DNA damage and sensitizes transformed cells to anti-tumor agents such as etoposide and doxorubicin. Here, we showed that depletion of HDAC6 in two NSCLC cell lines, H292 and A549, sensitized cells to cisplatin, one of the first-line chemotherapeutic agents used to treat NSCLC. We suggested that depletion of HDAC6 increased cisplatin-induced cytotoxicity was due to the enhancement of apoptosis via activating ATR/Chk1 pathway. Furthermore, we showed that HDAC6 protein levels were positively correlated with cisplatin IC50 in 15 NSCLC cell lines. Lastly, depletion of HDAC6 in H292 xenografts rendered decreased tumor weight and volume and exhibited increased basal apoptosis compared with the controls in a xenograft mouse model. In summary, our findings suggest that HDAC6 is positively associated with cisplatin resistance in NSCLC and reveal HDAC6 as a potential novel therapeutic target for platinum refractory NSCLC. PMID:22957056

  16. Long-Term Maintenance Therapy Using Rituximab-Induced Continuous B-Cell Depletion in Patients with ANCA Vasculitis

    PubMed Central

    Pendergraft, William F.; Cortazar, Frank B.; Wenger, Julia; Murphy, Andrew P.; Rhee, Eugene P.; Laliberte, Karen A.; Niles, John L.

    2014-01-01

    Background and objectives Remission in the majority of ANCA vasculitis patients is not sustained after a single course of rituximab, and risk of relapse warrants development of a successful strategy to ensure durable remission. Design, setting, participants, & measurements A retrospective analysis of ANCA vasculitis patients who underwent maintenance therapy using rituximab-induced continuous B-cell depletion for up to 7 years was performed. Maintenance therapy with rituximab was initiated after achieving remission or converting from other prior maintenance therapy. Continuous B-cell depletion was achieved in all patients by scheduled rituximab administration every 4 months. Disease activity, serologic parameters, adverse events, and survival were examined. Results In the study, 172 patients (mean age=60 years, 55% women, 57% myeloperoxidase–ANCA) treated from April of 2006 to March of 2013 underwent continuous B-cell depletion with rituximab. Median remission maintenance follow-up time was 2.1 years. Complete remission (Birmingham Vasculitis Activity Score [BVAS]=0) was achieved in all patients. Major relapse (BVAS≥3) occurred in 5% of patients and was associated with weaning of other immunosuppression drugs. Remission was reinduced in all patients. Survival mirrored survival of a general age-, sex-, and ethnicity-matched United States population. Conclusion This analysis provides evidence for long-term disease control using continuous B-cell depletion. This treatment strategy in ANCA vasculitis patients also seems to result in survival rates comparable with rates in a matched reference population. These findings suggest that prospective remission maintenance treatment trials using continuous B-cell depletion are warranted. PMID:24626432

  17. Type 2 innate immunity in helminth infection is induced redundantly and acts autonomously following CD11c(+) cell depletion.

    PubMed

    Smith, Katherine A; Harcus, Yvonne; Garbi, Natalio; Hmmerling, Gnter J; MacDonald, Andrew S; Maizels, Rick M

    2012-10-01

    Infection with gastrointestinal helminths generates a dominant type 2 response among both adaptive (Th2) and innate (macrophage, eosinophil, and innate lymphoid) immune cell types. Two additional innate cell types, CD11c(high) dendritic cells (DCs) and basophils, have been implicated in the genesis of type 2 immunity. Investigating the type 2 response to intestinal nematode parasites, including Heligmosomoides polygyrus and Nippostrongylus brasiliensis, we first confirmed the requirement for DCs in stimulating Th2 adaptive immunity against these helminths through depletion of CD11c(high) cells by administration of diphtheria toxin to CD11c.DOG mice. In contrast, responsiveness was intact in mice depleted of basophils by antibody treatment. Th2 responses can be induced by adoptive transfer of DCs, but not basophils, exposed to soluble excretory-secretory products from these helminths. However, innate type 2 responses arose equally strongly in the presence or absence of CD11c(high) cells or basophils; thus, in CD11c.DOG mice, the alternative activation of macrophages, as measured by expression of arginase-1, RELM-?, and Ym-1 (Chi3L3) in the intestine following H. polygyrus infection or in the lung following N. brasiliensis infection, was unaltered by depletion of CD11c-expressing DCs and alveolar macrophages or by antibody-mediated basophil depletion. Similarly, goblet cell-associated RELM-? in lung and intestinal tissues, lung eosinophilia, and expansion of innate lymphoid ("nuocyte") populations all proceeded irrespective of depletion of CD11c(high) cells or basophils. Thus, while CD11c(high) DCs initiate helminth-specific adaptive immunity, innate type 2 cells are able to mount an autonomous response to the challenge of parasite infection. PMID:22851746

  18. Neuropeptide Y-induced enhancement of the evoked release of newly synthesized dopamine in rat striatum: mediation by Y2 receptors.

    PubMed

    Adewale, Adepero Shola; Macarthur, Heather; Westfall, Thomas C

    2007-05-01

    The purpose of the present study was to determine whether or not activation of neuropeptide Y (NPY) receptors resulted in an enhancement or attenuation of the KCl (50 mM) evoked release of [3H]dopamine newly synthesized from [3H]tyrosine in superfused striatal slices and, if so to identify the NPY receptor subtype mediating the effect. Rat striatal slices were prepared and placed in microsuperfusion chambers and continuously superfused with physiological buffer containing 50 microCi/ml of l-3-5-[3H]tyrosine. Superfusate effluents were collected and analyzed for [3H]dopamine by liquid scintillation spectrometry following amberlite CG50 and alumina chromatography. NPY agonists (NPY and PYY3-36) were added 6 min prior to the addition of KCl, while the Y1, Y2, and Y5 antagonist BIBO3304, BIIE0246 and CGP71683A, respectively were added 6 min prior to the agonists. Continuous superfusion with [3H]tyrosine resulted in the production of [3H]dopamine which reached a steady state at approximately 48 min. Depolarization with KCl resulted in a 2- to 3-fold increase in [3H]dopamine overflow. NPY and PYY3-36 produced a concentration dependent enhancement in the KCl induced increase in newly synthesized [3H]dopamine overflow. The Y2 antagonist BIIE0246 produced an attenuation of both the NPY and PYY3-36 induced enhancement while the Y1 antagonist BIBO3304 and theY5 antagonist CGP71683A failed to alter the NPY or PYY3-36 induced enhancement. These results are consistent with the NPY-Y2 receptor subtype mediating the facilitatory effect. PMID:17382974

  19. Ghrelin receptor antagonism attenuates cocaine- and amphetamine-induced locomotor stimulation, accumbal dopamine release, and conditioned place preference

    PubMed Central

    Egecioglu, Emil; Dickson, Suzanne L.; Engel, Jrgen A.

    2010-01-01

    Introduction Recently we demonstrated that genetic or pharmacological suppression of the central ghrelin signaling system, involving the growth hormone secretagogue receptor 1A (GHS-R1A), lead to a reduced reward profile from alcohol. As the target circuits for ghrelin in the brain include a mesolimbic reward pathway that is intimately associated with reward-seeking behaviour, we sought to determine whether the central ghrelin signaling system is required for reward from drugs of abuse other than alcohol, namely cocaine or amphetamine. Results We found that amphetamineas well as cocaine-induced locomotor stimulation and accumbal dopamine release were reduced in mice treated with a GHS-R1A antagonist. Moreover, the ability of these drugs to condition a place preference was also attenuated by the GHS-R1A antagonist. Conclusions Thus GHS-R1A appears to be required not only for alcohol-induced reward, but also for reward induced by psychostimulant drugs. Our data suggest that the central ghrelin signaling system constitutes a novel potential target for treatment of addictive behaviours such as drug dependence. PMID:20559820

  20. Cocaine-Induced Behavioral Sensitization in Mice: Effects of Microinjection of Dopamine D2 Receptor Antagonist into the Nucleus Accumbens

    PubMed Central

    Jung, Eun-Sol; Lee, Hyo Jin; Sim, Hye-Ri

    2013-01-01

    To determine the role of dopamine D2 receptor (D2R) in the nucleus accumbens (NAc) core in cocaine-induced behavioral sensitization, D2R antagonist, raclopride was bilaterally microinjected (2.5 or 5 nmol) into the NAc core of WT and D2R-/- mice and the initiation and expression phase of cocaine-mediated locomotor sensitization were analyzed. WT and D2R knockout (D2R-/-) mice received bilateral injections of either saline, or raclopride at the NAc core 30 min before each of five daily repeated injections of saline or cocaine (15 mg/kg i.p.). Following 2 weeks of withdrawal after repeated exposure to cocaine, the animals were pre-treated with an intra-accumbal injection of vehicle or raclopride before receiving a systemic cocaine challenge for the expression of sensitization. Animals which had been microinjected raclopride into NAc core displayed the enhancement of cocaine-induced behavioral response for the initiation but also for the expression of sensitization in WT as well as in D2R-/- mice, which was thus unaltered as compared to vehicle-injected control group. These results suggest that D2R in NAc core is not involved in cocaine-induced behavioral sensitization. PMID:24167417

  1. Methylamine induced hypophagia is mediated via dopamine D1 and D2 receptors in neonatal meat chicks.

    PubMed

    Mahzouni, Mansour; Zendehdel, Morteza; Babapour, Vahab; Charkhkar, Saeed

    2016-03-01

    Recently, methylamine has been found as an endogenous amine, which is controling food intake in mammals. However, there is no evidence about the effect of methylamine on feeding behavior in poultry. So, the present study was designed to evaluate the effect of intracerebroventricular (ICV) injection of methylamine and involvement of central methylamine/dopaminergic systems on feeding behavior in neonatal meat type chicks. In experiment 1, chicks were ICV injected with different doses of methylamine (0.48, 0.96, 1.44, 1.92 and 2.40?mol). In experiment 2, chicks received a dose of either the control solution, 2.40?mol methylamine, 125nmolL-DOPA (dopamine precursor) or a combination of methylamine plus L-DOPA. Experiments 3-7 were similar to experiment 2 except that 150nmol 6-OHDA (dopamine synthase inhibitor), 5nmol SCH23390 (D1 receptor antagonist), 5nmol AMI-193 (D2 receptor antagonist), 6.4nmol NGB2904 (D3 receptor antagonist) and 6nmolL-741, 742 (D4 receptor antagonist) were used instead of 125nmolL-DOPA, respectively. Cumulative food intake was determined until 2h post-injection. According to the results, methylamine significantly decreased food intake in a dose dependent manner (p<0.05). The inhibitory effect of methylamine on food intake was significantly attenuated by 6-OHDA, SCH23390 and AMI-193 (P<0.05), but NGB2904 and L-741, 742 had no effect on food intake induced by methylamine. In addition, hypophagic effect of methylamine significantly amplified by L-DOPA (P<0.05). These results suggest that methylamine decrease food intake and there is an interaction between methylamine and dopaminergic system via D1 and D2 receptors in chickens. PMID:26685977

  2. Adolescent nicotine-induced dendrite remodeling in the nucleus accumbens is rapid, persistent, and D1-dopamine receptor dependent.

    PubMed

    Ehlinger, D G; Bergstrom, H C; Burke, J C; Fernandez, G M; McDonald, C G; Smith, R F

    2016-01-01

    Chronic nicotine exposure during adolescence induces dendritic remodeling of medium spiny neurons (MSNs) in the nucleus accumbens (NAcc) shell. While nicotine-induced dendritic remodeling has frequently been described as persistent, the trajectory of dendrite remodeling is unknown. Specifically, no study to date has characterized the structural plasticity of dendrites in the NAcc immediately following chronic nicotine, leaving open the possibility that dendrite remodeling emerges gradually over time. Further, the neuropharmacological mechanisms through which nicotine induces dendrite remodeling are not well understood. To address these questions, rats were co-administered chronic nicotine (0.5mg/kg) and the D1-dopamine receptor (D1DR) antagonist SCH-23390 (0.05mg/kg) subcutaneously every other day during adolescence. Brains were then processed for Golgi-Cox staining either 1day or 21days following drug exposure and dendrites from MSNs in the NAcc shell digitally reconstructed in 3D. Spine density was also measured at both time points. Our morphometric results show (1) the formation of new dendritic branches and spines 1day following nicotine exposure, (2) new dendritic branches, but not spine density, remains relatively stable for at least 21days, (3) the co-administration of SCH-23390 completely blocked nicotine-induced dendritic remodeling of MSNs at both early and late time points, suggesting the formation of new dendritic branches in response to nicotine is D1DR-dependent, and (4) SCH-23390 failed to block nicotine-induced increases in spine density. Overall this study provides new insight into how nicotine influences the normal trajectory of adolescent brain development and demonstrates a persistent form of nicotine-induced neuroplasticity in the NAcc shell that develops rapidly and is D1DR dependent. PMID:25257604

  3. Central serotonin(2B) receptor blockade inhibits cocaine-induced hyperlocomotion independently of changes of subcortical dopamine outflow.

    PubMed

    Devroye, Cline; Cathala, Adeline; Di Marco, Barbara; Caraci, Filippo; Drago, Filippo; Piazza, Pier Vincenzo; Spampinato, Umberto

    2015-10-01

    The central serotonin2B receptor (5-HT2BR) is currently considered as an interesting pharmacological target for improved treatment of drug addiction. In the present study, we assessed the effect of two selective 5-HT2BR antagonists, RS 127445 and LY 266097, on cocaine-induced hyperlocomotion and dopamine (DA) outflow in the nucleus accumbens (NAc) and the dorsal striatum of freely moving rats. The peripheral administration of RS 127445 (0.16mg/kg, i.p.) or LY 266097 (0.63mg/kg, i.p.) significantly reduced basal DA outflow in the NAc shell, but had no effect on cocaine (10mg/kg, i.p.)-induced DA outflow in this brain region. Also, RS 127445 failed to modify both basal and cocaine-induced DA outflow in the NAc core and the dorsal striatum. Conversely, both 5-HT2BR antagonists reduced cocaine-induced hyperlocomotion. Furthermore, RS 127445 as well as the DA-R antagonist haloperidol (0.1mg/kg, i.p.) reduced significantly the late-onset hyperlocomotion induced by the DA-R agonist quinpirole (0.5mg/kg, s.c.). Altogether, these results demonstrate that 5-HT2BR blockade inhibits cocaine-induced hyperlocomotion independently of changes of subcortical DA outflow. This interaction takes place downstream to DA neurons and could involve an action at the level of dorsostriatal and/or NAc DA transmission, in keeping with the importance of these brain regions in the behavioural responses of cocaine. Overall, this study affords additional knowledge into the regulatory control exerted by the 5-HT2BR on ascending DA pathways, and provides additional support to the proposed role of 5-HT2BRs as a new pharmacological target in drug addiction. PMID:26116760

  4. Changes in striatal electroencephalography and neurochemistry induced by kainic acid seizures are modified by dopamine receptor antagonists.

    PubMed

    Bourne, J A; Fosbraey, P; Halliday, J

    2001-02-16

    We investigated the involvement of striatal dopamine release in electrographic and motor seizure activity evoked by kainic acid in the guinea pig. The involvement of the dopamine receptor subtypes was studied by systemic administration of the dopamine D(1) receptor antagonist, R(+)-7-chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine hydrochloride (SCH 23390; 0.5 mg kg(-1)), or the dopamine D(2) antagonist, (5-aminosulphonyl)-N-[(1-ethyl-2-pyrrolidinyl)-methyl]-2-methoxybenzamide (sulpiride, 30 mg kg(-1)). Microdialysis and high performance liquid chromatography were used to monitor changes in extracellular levels of striatal dopamine and its metabolites, glutamate, aspartate and gamma-amino-butyric acid (GABA). These data were correlated with changes in the striatal and cortical electroencephalographs and clinical signs. We found that, although neither dopamine receptor antagonist inhibited behavioural seizure activity, blockade of the dopamine D(1)-like receptor with SCH 23390 significantly reduced both the 'power' of the electrical seizure activity and the associated change in extracellular striatal concentration of glutamate, whilst increasing the extracellular striatal concentration of GABA. In contrast, blockade of the dopamine D(2)-like receptor with sulpiride significantly increased the extracellular, striatal content of glutamate and the dopamine metabolites. These results confirm previous evidence in other models of chemically-evoked seizures that antagonism of the dopamine D(1) receptor tends to reduce motor and electrographic seizure activity as well as excitatory amino-acid transmitter activity, while antagonism of the dopamine D(2) receptor has relatively less apparent effect. PMID:11226392

  5. Numerical validation of axial plasma momentum lost to a lateral wall induced by neutral depletion

    NASA Astrophysics Data System (ADS)

    Takao, Yoshinori; Takahashi, Kazunori

    2015-11-01

    Momentum imparted to a lateral wall of a compact inductively coupled plasma thruster is numerically investigated for argon and xenon gases by a particle-in-cell simulation with Monte Carlo collisions (PIC-MCC). Axial plasma momentum lost to a lateral wall is clearly shown when axial depletion of the neutrals is enhanced, which is in qualitative agreement with the result in a recent experiment using a helicon plasma source [Takahashi et al., Phys. Rev. Lett. 114, 195001 (2015)]. The PIC-MCC calculations demonstrate that the neutral depletion causes an axially asymmetric profile of the plasma density and potential, leading to axial ion acceleration and the non-negligible net axial force exerted to the lateral wall in the opposite direction of the thrust.

  6. Octopamine and Dopamine differentially modulate the nicotine-induced calcium response in Drosophila Mushroom Body Kenyon Cells.

    PubMed

    Leyton, V; Goles, N I; Fuenzalida-Uribe, N; Campusano, J M

    2014-02-01

    In Drosophila associative olfactory learning, an odor, the conditioned stimulus (CS), is paired to an unconditioned stimulus (US). The CS and US information arrive at the Mushroom Bodies (MB), a Drosophila brain region that processes the information to generate new memories. It has been shown that olfactory information is conveyed through cholinergic inputs that activate nicotinic acetylcholine receptors (nAChRs) in the MB, while the US is coded by biogenic amine (BA) systems that innervate the MB. In this regard, the MB acts as a coincidence detector. A better understanding of the properties of the responses gated by nicotinic and BA receptors is required to get insights on the cellular and molecular mechanisms responsible for memory formation. In recent years, information has become available on the properties of the responses induced by nAChR activation in Kenyon Cells (KCs), the main neuronal MB population. However, very little information exists on the responses induced by aminergic systems in fly MB. Here we have evaluated some of the properties of the calcium responses gated by Dopamine (DA) and Octopamine (Oct) in identified KCs in culture. We report that exposure to BAs induces a fast but rather modest increase in intracellular calcium levels in cultured KCs. The responses to Oct and DA are fully blocked by a VGCC blocker, while they are differentially modulated by cAMP. Moreover, co-application of BAs and nicotine has different effects on intracellular calcium levels: while DA and nicotine effects are additive, Oct and nicotine induce a synergistic increase in calcium levels. These results suggest that a differential modulation of nicotine-induced calcium increase by DA and Oct could contribute to the events leading to learning and memory in flies. PMID:24334164

  7. Dopamine D3 Receptors in the Basolateral Amygdala and the Lateral Habenula Modulate Cue-Induced Reinstatement of Nicotine Seeking

    PubMed Central

    Khaled, Maram ATM; Pushparaj, Abhiram; Di Ciano, Patricia; Diaz, Jorge; Le Foll, Bernard

    2014-01-01

    Dopamine D3 receptors are implicated in cue-induced relapse to drug seeking. We have previously shown that systemic administration of a selective D3 antagonist reduces cue-induced reinstatement of nicotine seeking in rats. The current study sought to investigate potential neural substrates mediating this effect. The D3 antagonist SB-277011-A (0.011??g/0.5??l/side) infused into the basolateral amygdala or the lateral habenula, but not the nucleus accumbens, significantly attenuated cue-induced reinstatement of nicotine seeking. Moreover, infusion of SB-277011-A (1??g/0.5??l/side) into the basolateral amygdala or lateral habenula had no effect on food self-administration. Together with the finding that systemic SB-277011-A had no effect on extinction responding, this suggests that the effects observed here were on reinstatement and cue seeking, and not due to nonspecific motor activation or contextual-modified residual responding. The further finding of binding of [125I]7-OH-PIPAT to D3 receptors in the lateral habenula and in the basolateral amygdala is consistent with an important role of D3 receptors in these areas in nicotine seeking. It was also found that systemic administration of the selective D2 antagonist L741626 decreased cue-induced reinstatement, consistent with a role of D2 and D3 receptors in modulating this behavior. The current study supports an important role for D3 receptors in the basolateral amygdala and lateral habenula in cue-induced reinstatement. PMID:24998621

  8. Exposure to repeated immobilization stress inhibits cocaine-induced increase in dopamine extracellular levels in the rat ventral tegmental area.

    PubMed

    Sotomayor-Zrate, Ramn; Abarca, Jorge; Araya, Katherine A; Renard, Georgina M; Andrs, Mara E; Gysling, Katia

    2015-11-01

    A higher vulnerability to drug abuse has been observed in human studies of individuals exposed to chronic or persistent stress, as well as in animal models of drug abuse. Here, we explored the effect of repeated immobilization stress on cocaine-induced increase in dopamine extracellular levels in VTA and its regulation by corticotropin-releasing factor (CRF) and GABA systems. Cocaine (10mg/Kg i.p.) induced an increase of VTA DA extracellular levels in control rats. However, this effect was not observed in repeated stress rats. Considering the evidence relating stress with CRF, we decided to perfuse CRF and CP-154526 (selective antagonist of CRF1 receptor) in the VTA of control and repeated stress rats, respectively. We observed that perfusion of 20?M CRF inhibited the increase of VTA DA extracellular levels induced by cocaine in control rats. Interestingly, we observed that in the presence of 10?M CP-154526, cocaine induced a significant increase of VTA DA extracellular levels in repeated stress rats. Regarding the role of VTA GABA neurotransmission, cocaine administration induced a significant increase in VTA GABA extracellular levels only in repeated stress rats. Consistently, cocaine was able to increase VTA DA extracellular levels in repeated stress rats when 100?M bicuculline, an antagonist of GABAA receptor, was perfused intra VTA. Thus, both CRF and GABA systems are involved in the lack of response to cocaine in the VTA of repeated stress rats. It is tempting to suggest that the loss of response in VTA dopaminergic neurons to cocaine, after repeated stress, is due to an interaction between CRF and GABA systems. PMID:26318765

  9. Dopamine D3 receptors in the basolateral amygdala and the lateral habenula modulate cue-induced reinstatement of nicotine seeking.

    PubMed

    Khaled, Maram A T M; Pushparaj, Abhiram; Di Ciano, Patricia; Diaz, Jorge; Le Foll, Bernard

    2014-12-01

    Dopamine D3 receptors are implicated in cue-induced relapse to drug seeking. We have previously shown that systemic administration of a selective D3 antagonist reduces cue-induced reinstatement of nicotine seeking in rats. The current study sought to investigate potential neural substrates mediating this effect. The D3 antagonist SB-277011-A (0.01-1 ?g/0.5 ?l/side) infused into the basolateral amygdala or the lateral habenula, but not the nucleus accumbens, significantly attenuated cue-induced reinstatement of nicotine seeking. Moreover, infusion of SB-277011-A (1 ?g/0.5 ?l/side) into the basolateral amygdala or lateral habenula had no effect on food self-administration. Together with the finding that systemic SB-277011-A had no effect on extinction responding, this suggests that the effects observed here were on reinstatement and cue seeking, and not due to nonspecific motor activation or contextual-modified residual responding. The further finding of binding of [(125)I]7-OH-PIPAT to D3 receptors in the lateral habenula and in the basolateral amygdala is consistent with an important role of D3 receptors in these areas in nicotine seeking. It was also found that systemic administration of the selective D2 antagonist L741626 decreased cue-induced reinstatement, consistent with a role of D2 and D3 receptors in modulating this behavior. The current study supports an important role for D3 receptors in the basolateral amygdala and lateral habenula in cue-induced reinstatement. PMID:24998621

  10. Comparative study of femtosecond and nanosecond laser-induced breakdown spectroscopy of depleted uranium

    SciTech Connect

    Emmert, Luke A.; Chinni, Rosemarie C.; Cremers, David A.; Jones, C. Randy; Rudolph, Wolfgang

    2011-01-20

    We present spectra of depleted uranium metal from laser plasmas generated by nanosecond Nd:YAG (1064 nm) and femtosecond Ti:sapphire (800 nm) laser pulses. The latter pulses produce short-lived and relatively cool plasmas in comparison to the longer pulses, and the spectra of neutral uranium atoms appear immediately after excitation. Evidence for nonequilibrium excitation with femtosecond pulses is found in the dependence of spectral line intensities on the pulse chirp.

  11. Sphingomyelin Depletion Impairs Anionic Phospholipid Inward Translocation and Induces Cholesterol Efflux*

    PubMed Central

    Gulshan, Kailash; Brubaker, Gregory; Wang, Shuhui; Hazen, Stanley L.; Smith, Jonathan D.

    2013-01-01

    The phosphatidylserine (PS) floppase activity (outward translocation) of ABCA1 leads to plasma membrane remodeling that plays a role in lipid efflux to apolipoprotein A-I (apoAI) generating nascent high density lipoprotein. The Tangier disease W590S ABCA1 mutation has defective PS floppase activity and diminished cholesterol efflux activity. Here, we report that depletion of sphingomyelin by inhibitors or sphingomyelinase caused plasma membrane remodeling, leading to defective flip (inward translocation) of PS, higher PS exposure, and higher cholesterol efflux from cells by both ABCA1-dependent and ABCA1-independent mechanisms. Mechanistically, sphingomyelin was connected to PS translocation in cell-free liposome studies that showed that sphingomyelin increased the rate of spontaneous PS flipping. Depletion of sphingomyelin in stably transfected HEK293 cells expressing the Tangier disease W590S mutant ABCA1 isoform rescued the defect in PS exposure and restored cholesterol efflux to apoAI. Liposome studies showed that PS directly increased cholesterol accessibility to extraction by cyclodextrin, providing the mechanistic link between cell surface PS and cholesterol efflux. We conclude that altered plasma membrane environment conferred by depleting sphingomyelin impairs PS flip and promotes cholesterol efflux in ABCA1-dependent and -independent manners. PMID:24220029

  12. Micelle-induced depletion interaction and resultant structure in charged colloidal nanoparticle system

    NASA Astrophysics Data System (ADS)

    Ray, D.; Aswal, V. K.; Kohlbrecher, J.

    2015-04-01

    The evolution of the interaction and the resultant structure in the mixed system of anionic silica nanoparticles (Ludox LS30) and non-ionic surfactant decaethylene glycol monododecylether (C12E10), undergoing phase separation, have been studied using small-angle neutron scattering and dynamic light scattering. The measurements have been carried out for a fixed concentration of nanoparticle (1 wt. %) with varying concentration of surfactant (0 to 1 wt. %), in the absence and presence of an electrolyte. It is found that the micelles of non-ionic surfactant adsorb on the nanoparticle in the absence of electrolyte (form stable system), whereas these micelles become non-adsorbing in the presence of electrolyte (show phase separation). The phase separation arises because of C12E10 micelles, causing depletion interaction between nanoparticles and leading to their aggregation. The interaction is modeled by double Yukawa potential accounting for attractive depletion as well as repulsive electrostatic forces. Both the interactions (attraction and repulsion) are found to be of long-range. The nanoparticle aggregation (phase separation) is governed by the increase in the magnitude and the range of the depletion attraction with the increase in the surfactant concentration. The nanoparticle aggregates formed are quite large in size (order of micron) and are characterized by the surface fractal having simple cubic packing of nanoparticles within the aggregates.

  13. Micelle-induced depletion interaction and resultant structure in charged colloidal nanoparticle system

    SciTech Connect

    Ray, D.; Aswal, V. K.; Kohlbrecher, J.

    2015-04-28

    The evolution of the interaction and the resultant structure in the mixed system of anionic silica nanoparticles (Ludox LS30) and non-ionic surfactant decaethylene glycol monododecylether (C12E10), undergoing phase separation, have been studied using small-angle neutron scattering and dynamic light scattering. The measurements have been carried out for a fixed concentration of nanoparticle (1 wt. %) with varying concentration of surfactant (0 to 1 wt. %), in the absence and presence of an electrolyte. It is found that the micelles of non-ionic surfactant adsorb on the nanoparticle in the absence of electrolyte (form stable system), whereas these micelles become non-adsorbing in the presence of electrolyte (show phase separation). The phase separation arises because of C12E10 micelles, causing depletion interaction between nanoparticles and leading to their aggregation. The interaction is modeled by double Yukawa potential accounting for attractive depletion as well as repulsive electrostatic forces. Both the interactions (attraction and repulsion) are found to be of long-range. The nanoparticle aggregation (phase separation) is governed by the increase in the magnitude and the range of the depletion attraction with the increase in the surfactant concentration. The nanoparticle aggregates formed are quite large in size (order of micron) and are characterized by the surface fractal having simple cubic packing of nanoparticles within the aggregates.

  14. Bupropion, methylphenidate, and 3,4-methylenedioxypyrovalerone antagonize methamphetamine-induced efflux of dopamine according to their potencies as dopamine uptake inhibitors: implications for the treatment of methamphetamine dependence

    PubMed Central

    2013-01-01

    Background Methamphetamine-abuse is a worldwide health problem for which no effective therapy is available. Inhibition of methamphetamine-induced transporter-mediated dopamine (DA) release could be a useful approach to treat methamphetamine-addiction. We assessed the potencies of bupropion, methylphenidate, and 3,4-methylenedioxypyrovalerone (MDPV) to block DA uptake or to inhibit methamphetamine-induced DA release in HEK-293 cells expressing the human DA transporter. Findings Bupropion, methylphenidate, and MDPV inhibited methamphetamine-induced DA release with relative potencies corresponding to their potencies to block DA uptake (potency ranks: MDPV > methylphenidate > bupropion). Conclusions Bupropion and methylphenidate antagonize the effects of methamphetamine in vitro and may be potential candidates for the treatment of stimulant addiction. However, drugs that very potently antagonize the effect of methamphetamine are likely to also exhibit considerable abuse liability (MDPV > methylphenidate > bupropion). PMID:23734766

  15. Neuroprotective Effects of Jitai Tablet, a Traditional Chinese Medicine, on the MPTP-Induced Acute Model of Parkinson's Disease: Involvement of the Dopamine System

    PubMed Central

    Liu, Jia; Gao, Jinlong; Xu, Shasha; Liu, Ying; Shang, Weihu; Gu, Chenxin; Huang, Yiyun; Han, Mei

    2014-01-01

    Jitai tablet (JTT) is a traditional Chinese medicine used to treat neuropsychiatric disorders. We previously demonstrated that JTT treatment led to increased level of dopamine transporter (DAT) in the striatum, thus indicating that JTT might have therapeutic potential for Parkinson's disease (PD), which is characterized by dysregulated dopamine (DA) transmission and decreased striatal DAT expression. The aim of this study was to investigate the neuroprotective effect of JTT on MPTP-induced PD mice. Using locomotor activity test and rotarod test, we evaluated the effects of JTT (0.50, 0.15, or 0.05?g/kg) on MPTP-induced behavioral impairments. Tyrosine hydroxylase TH-positive neurons in the substantia nigra and DAT and dopamine D2 receptor (D2R) levels in the striatum were detected by immunohistochemical staining and/or autoradiography. Levels of DA and its metabolites were determined by HPLC. In MPTP-treated mice, behavioral impairments were alleviated by JTT treatment. Moreover, JTT protected against impairment of TH-positive neurons and attenuated the MPTP-induced decreases in DAT and D2R. Finally, high dose of JTT (0.50?g/kg) inhibited the MPTP-induced increase in DA metabolism rate. Taken together, results from our present study provide evidence that JTT offers neuroprotective effects against the neurotoxicity of MPTP and thus might be a potential treatment for PD. PMID:24799940

  16. Dopamine agonists rescue Aβ-induced LTP impairment by Src-family tyrosine kinases.

    PubMed

    Yuan Xiang, PingAn; Janc, Oliwia; Grochowska, Katarzyna M; Kreutz, Michael R; Reymann, Klaus G

    2016-04-01

    Soluble forms of oligomeric amyloid beta (AβO) are involved in the loss of synaptic plasticity and memory, especially in early phases of Alzheimer's disease. Stimulation of dopamine D1/D5 receptors (D1R/D5R) is known to increase surface expression of synaptic α-amino-3-hydroxyl-5-methyl-4-isoxazole-propionate subtype glutamate and N-methyl-D-aspartate subtype glutamate receptors and facilitates the induction of the late phase of long-term potentiation (LTP), probably via a related mechanism. In this study, we show that the D1/D5R agonist SKF38393 protects LTP of hippocampal CA1 synapses from the deleterious action of oligomeric amyloid beta. Unexpectedly, the D1R/D5R-mediated recovery of LTP is independent of protein kinase A or phospholipase C pathways. Instead, we found that the inhibition of Src-family tyrosine kinases completely abolished the protective effects of D1R/D5R stimulation in a cellular model of learning and memory. PMID:26973108

  17. Radiation-enhanced gate-induced-drain-leakage current in the 130 nm partially-depleted SOI pMOSFET

    NASA Astrophysics Data System (ADS)

    Peng, Chao; Hu, Zhiyuan; Ning, Bingxu; Dai, Lihua; Bi, Dawei; Zhang, Zhengxuan

    2015-04-01

    The total ionizing dose (TID) effect of the pMOSFET from 130 nm partially-depleted silicon-on-insulator (PDSOI) is investigated. The data obtained from 60Co ?-ray irradiation experiments indicate that input/output (I/O) device is more susceptible to TID effect than the core device. An anomalous off-state leakage increase is observed for I/O pMOSFET when drain is biased at a high voltage after irradiation. It is proved that this radiation-induced leakage relates to the enhanced gate-induce-drain-leakage (GIDL). Both the radiation-induced interface traps at the gate-oxide/body interface and the oxide trapped charges in the buried oxide (BOX) are responsible for the growth of the leakage current. These conclusions are also verified by the TCAD simulations. The isothermal annealing can recover the leakage current to the pre-irradiation level.

  18. Potential involvement of oxygen intermediates and glutathione depletion in UV-induced epidermal cell injury in vitro

    SciTech Connect

    Hsieh, G.C.; Acosta, D. )

    1991-03-11

    Generation of reactive oxygen species (ROS) and depletion of glutathione (GSH) are suggested as the cytotoxic mechanisms for UVB-induced cellular damage. Primary monolayer cultures of epidermal keratinocytes (KCs) prepared from the skin of neonatal rats were irradiated with UVB at levels of 0.25-3.0 J/cm{sup 2}. Cytotoxicity was measured at 3, 6, and 12 hr after UVB radiation. Exposure of KCs to UVB resulted in time- and dose-related toxic responses as determined by plasma membrane integrity, lysosomal function and mitochondrial metabolic activity. Irradiated KCs generated superoxide in a dose-dependent manner when compared to sham-irradiated cells. Superoxide formation, which occurred before and concomitant with cell injury, was decreased by superoxide dismutase (SOD). Cell injury was also significantly prevented by ROS scavengers, SOD and catalase. Pretreatment of cells with endocytosis inhibitors, cytochalasin B and methylamine, suppressed the ability of SOD and catalase to protect keratinocytes from UVB-induced toxicity. Irradiation of cells with UVB caused rapid depletion of GSH to about 30% of unirradiated levels within 15 min. UVB-irradiation led to a rapid transient increase in GSH peroxidase activity, concomitant with a marked decrease in the GSH/GSSG ratio. After 1 hr., while the GSH/GSSG ratio remained low, the GSH peroxidase activity declined below the control levels in UVB-treated epidermal cells. Following extensive GSH depletion in cells preincubated with 0.1 mM buthiomine sulfoximine, KCs became strongly sensitized to the cytotoxic action of UVB. These results indicate that UVB-induced cell injury in cultured KCs may be mediated by ROs and that endogenous GSH may play an important protective role against the cytotoxic action of UVB.

  19. Diffraction barrier breakthrough in coherent anti-Stokes Raman scattering microscopy by additional probe-beam-induced phonon depletion

    SciTech Connect

    Liu Wei; Niu Hanben

    2011-02-15

    We provide an approach to significantly break the diffraction limit in coherent anti-Stokes Raman scattering (CARS) microscopy via an additional probe-beam-induced photon depletion (APIPD). The additional probe beam, whose profile is doughnut shaped and whose wavelength is different from the Gaussian probe beam, depletes the phonons to yield an unwanted anti-Stokes signal within a certain bandwidth at the rim of the diffraction-limited spot. When the Gaussian probe beam that follows immediately arrives, no anti-Stokes signal is generated in this region, resembling stimulated emission depletion (STED) microscopy, and the spot-generating useful anti-Stokes signals by this beam are substantially suppressed to a much smaller dimension. Scanning the spot renders three-dimensional, label-free, and chemically selective CARS images with subdiffraction resolution. Also, resolution-enhanced images of the molecule, specified by its broadband even-total CARS spectral signals not only by one anti-Stokes signal for its special chemical bond, can be obtained by employing a supercontinuum source.

  20. Danger peptide receptor signaling in plants ensures basal immunity upon pathogen-induced depletion of BAK1.

    PubMed

    Yamada, Kohji; Yamashita-Yamada, Misuzu; Hirase, Taishi; Fujiwara, Tadashi; Tsuda, Kenichi; Hiruma, Kei; Saijo, Yusuke

    2016-01-01

    Pathogens infect a host by suppressing defense responses induced upon recognition of microbe-associated molecular patterns (MAMPs). Despite this suppression, MAMP receptors mediate basal resistance to limit host susceptibility, via a process that is poorly understood. The Arabidopsis leucine-rich repeat (LRR) receptor kinase BAK1 associates and functions with different cell surface LRR receptors for a wide range of ligands, including MAMPs. We report that BAK1 depletion is linked to defense activation through the endogenous PROPEP peptides (Pep epitopes) and their LRR receptor kinases PEPR1/PEPR2, despite critical defects in MAMP signaling. In bak1-knockout plants, PEPR elicitation results in extensive cell death and the prioritization of salicylate-based defenses over jasmonate-based defenses, in addition to elevated proligand and receptor accumulation. BAK1 disruption stimulates the release of PROPEP3, produced in response to Pep application and during pathogen challenge, and renders PEPRs necessary for basal resistance. These findings are biologically relevant, since specific BAK1 depletion coincides with PEPR-dependent resistance to the fungal pathogen Colletotrichum higginsianum. Thus, the PEPR pathway ensures basal resistance when MAMP-triggered defenses are compromised by BAK1 depletion. PMID:26574534

  1. Aristolochic acid I induced oxidative DNA damage associated with glutathione depletion and ERK1/2 activation in human cells.

    PubMed

    Yu, Feng-Yih; Wu, Ting-Shuan; Chen, Ting-Wei; Liu, Biing-Hui

    2011-06-01

    Aristolochic acid I (AAI) has been widely found in herbal remedies and linked to the development of nephropathy and urothelial carcinoma in humans. This study elucidated the mechanism of oxidative stress and DNA damage mediated by AAI in human cells. Treatment of human promyelocytic leukemia cells (HL-60) and human renal proximal tubular cells (HK-2) with AAI led to a dose-dependent increase of reactive oxygen species (ROS). AAI also elevated the levels of DNA strand breaks and 8-hydroxy guanosine in HL-60 and HK-2 cells. Antioxidants, including Tiron, N-acetyl-l-cysteine (NAC) and glutathione (GSH), effectively suppressed the AAI-induced ROS and AAI-elicited genotoxicity, indicating that AAI induced the DNA damage through oxidative stress. GSH depletion was also found in AAI-treated cultures and proceeded prior to ROS formation. Exposure of HL-60 cells with AAI activated both ERK1/2 and p38 kinase phosphorylation, while only MEK1/2 inhibitor, U0126, significantly decreased AAI-mediated ROS. Preincubation of cells with thiol-containing compounds (NAC and GSH) inhibited the caspase 3 activity triggered by AAI, but non-thiol Tiron did not show a similar effect. This study demonstrated that AAI treatment results in oxidative stress-related DNA damage through GSH depletion and ERK1/2 activation; AAI-induced apoptosis is associated with GSH loss, but is independent of ROS generation. PMID:21300145

  2. Studies on the mechanisms underlying amiloride enhancement of 3,4-methylenedioxymethamphetamine-induced serotonin depletion in rats.

    PubMed

    Goi-Allo, Beatriz; Puerta, Elena; Hervias, Isabel; Di Palma, Richard; Ramos, Maria; Lasheras, Berta; Aguirre, Norberto

    2007-05-21

    Amiloride and several of its congeners known to block the Na(+)/Ca(2+) and/or Na(+)/H(+) antiporters potentiate methamphetamine-induced neurotoxicity without altering methamphetamine-induced hyperthermia. We now examine whether amiloride also exacerbates 3,4-methylenedioxymethamphetamine (MDMA)-induced long-term serotonin (5-HT) loss in rats. Amiloride (2.5 mg/kg, every 2 h x 3, i.p.) given at ambient temperature 30 min before MDMA (5 mg/kg, every 2 h x 3, i.p.), markedly exacerbated long-term 5-HT loss. However, in contrast to methamphetamine, amiloride also potentiated MDMA-induced hyperthermia. Fluoxetine (10 mg/kg i.p.) completely protected against 5-HT depletion caused by the MDMA/amiloride combination without significantly altering the hyperthermic response. By contrast, the calcium channel antagonists flunarizine or diltiazem did not afford any protection. Findings with MDMA and amiloride were extended to the highly selective Na(+)/H(+) exchange inhibitor dimethylamiloride, suggesting that the potentiating effects of amiloride are probably mediated by the blockade of Na(+)/H(+) exchange. When the MDMA/amiloride combination was administered at 15 degrees C hyperthermia did not develop and brain 5-HT concentrations remained unchanged 7 days later. Intrastriatal perfusion of MDMA (100 microM for 8 h) in combination with systemic amiloride caused a small depletion of striatal 5-HT content in animals made hyperthermic but not in the striatum of normothermic rats. These data suggest that enhancement of MDMA-induced 5-HT loss caused by amiloride or dimethylamiloride depends on their ability to enhance MDMA-induced hyperthermia. We hypothesise that blockade of Na(+)/H(+) exchange could synergize with hyperthermia to render 5-HT terminals more vulnerable to the toxic effects of MDMA. PMID:17320075

  3. Differential modulation of ghrelin-induced GH and LH release by PACAP and dopamine in goldfish pituitary cells.

    PubMed

    Grey, Caleb L; Chang, John P

    2013-09-15

    Ghrelin (GRLN) participates in multiple physiological processes, including the regulation of growth hormone (GH) and luteinizing hormone (LH) release. In the goldfish, neuroendocrine control of GH and LH release are multifactorial. In this system, pituitary adenylate cyclase-activating polypeptide (PACAP)-stimulated GH and LH secretion, as well as dopamine (DA)-induced GH release, are mediated by protein kinase A (PKA)-dependent, but protein kinase C (PKC)-independent, mechanisms. In addition, DA inhibits LH secretion by actions at sites along both PKA and PKC signaling pathways. Recently, goldfish GRLN (gGRLN19) has been shown to induce GH release via PKC, and LH secretion via both PKC and PKA. To further understand the neuroendocrine regulation of goldfish GH and LH release, we examined the effects of DA and PACAP on gGRLN19 actions in primary cultures of goldfish pituitary cells in perifusion and in Ca(2+)-imaging experiments. Consistent with their known intracellular signaling mechanisms in gonadotrophs, DA inhibited gGRLN19-induced LH release while cotreatment of PACAP and gGRLN19 did not produce additive LH responses. When applied prior to gGRLN19, PACAP potentiated gGRLN19-induced GH release and Ca(2+) signals within somatotrophs. In contrast, neither prior treatment with DA followed by gGRLN19 nor pretreatment with gGRLN19 prior to PACAP produced an enhanced GH release response. These observations suggest that PKA activators positively modulate gGRLN19 actions on goldfish somatotrophs in a ligand- and treatment order-specific manner. Results add to our understanding of the complexity of neuroendocrine control of GH and LH release at the pituitary cell level, and our understanding of GRLN action. PMID:23851105

  4. Genetic Variance Contributes to Dopamine Receptor Antagonist-Induced Inhibition of Sucrose Intake in Inbred and Outbred Mouse Strains

    PubMed Central

    Dym, Cheryl T.; Pinhas, Alexander; Robak, Magdalena; Sclafani, Anthony; Bodnar, Richard J.

    2009-01-01

    Preference and intake of sucrose varies across inbred and outbred strains of mice. Pharmacological analyses revealed that the greatest sensitivity to naltrexone-induced inhibition of sucrose (10%) intake was observed in C57BL10/J and C57BL/6J strains, whereas 129P3/J, SWR/J and SJL/J strains displayed far less sensitivity to naltrexone-induced inhibition of sucrose intake. Given that dopamine D1 (SCH23390) and D2 (raclopride) receptor antagonism potently reduce sucrose intake in outbred rat and mouse strains, the present study examined the possibility of genetic variance in the dose-dependent (501600 nmol/kg) and time-dependent (5120 min) effects of these antagonists upon sucrose (10%) intake in the eight inbred (BALB/cJ, C3H/HeJ, C57BL/6J, C57BL/10J, DBA/2J, SJL/J, SWR/J, 129P3/J) and one outbred (CD-1) mouse strains previously tested with naltrexone. SCH23390 significantly reduced sucrose intake across all five doses in 129P3/J and SJL/J mice, across four doses in C57BL/6J and BALB/cJ mice, across three doses in DBA/2J, SWR/J, C3H/HeJ and C57BL/10J mice, but only at the two highest doses in CD-1 mice. SCH23390 was 23-fold more potent in inhibiting sucrose intake in 129P3/J and SJL/J mice relative to CD-1 mice. In contrast, only the highest equimolar 1600 nmol/kg dose of raclopride significantly reduced sucrose intake in the BALB/cJ, C3H/HeJ, C57BL/6J, C57BL/10J, DBA/2J, SJL/J and 129P3/J, but not the SWR/J and CD-1 strains. The present and previous data demonstrate specific and differential patterns of genetic variability in inhibition of sucrose intake by dopamine and opioid antagonists, suggesting that distinct neurochemical mechanisms control sucrose intake across different mouse strains. PMID:19135035

  5. Role of dopamine D1-like receptor within the nucleus accumbens in acute food deprivation- and drug priming-induced reinstatement of morphine seeking in rats.

    PubMed

    Sadeghzadeh, Fatemeh; Babapour, Vahab; Haghparast, Abbas

    2015-01-01

    Dopamine is a predominant neurotransmitter in the nervous system, which plays an important role in both drug priming- and cue-induced reinstatement of cocaine and heroin seeking. Therefore, in the present study, the conditioned place preference (CPP) paradigm was used to evaluate the effects of intra-accumbal administration of SCH23390 as a dopamine D1-like receptor antagonist on food deprivation (FD) and drug priming-induced reinstatement. Sixty-eight adult male albino Wistar rats weighing 200-280 g were bilaterally implanted by cannulae into the nucleus accumbens (NAc). For induction of the CPP, subcutaneous (sc) administration of morphine (5mg/kg) was used daily during a three-day conditioning phase. The conditioning score and locomotor activity were recorded by using the Ethovision software. Under extinction conditions, rats were given an 'off' period and were tested for FD-induced reinstatement following the 24-h or 48-h FD condition, and for drug priming-induced reinstatement under the sated condition following an injection of 0.5 and 1mg/kg (sc) morphine. In the next experiments, animals received different doses of intra-accumbal SCH23390 (0.25, 1 and 4 ?g/0.5 ?l saline) bilaterally and were subsequently tested for FD- and morphine priming-induced reinstatement. Our findings indicated that only a dose of 1mg/kg and not 0.5mg/kg of morphine induced the reinstatement of morphine. 24-h FD similar to 48-h FD induced the reinstatement of seeking behaviors facilitated by an ineffective dose of morphine (0.5mg/kg). Furthermore, the D1-like receptor antagonist attenuated FD- and drug priming-induced reinstatement dose-dependently. It is concluded that FD- and drug priming-induced reinstatement may be mediated, at least in some way, by activation of dopamine D1-like receptors in the NAc. PMID:25835321

  6. Dopamine transporter down-regulation following repeated cocaine: implications for 3,4-methylenedioxymethamphetamine-induced acute effects and long-term neurotoxicity in mice

    PubMed Central

    Peraile, I; Torres, E; Mayado, A; Izco, M; Lopez-Jimenez, A; Lopez-Moreno, JA; Colado, MI; O'Shea, E

    2010-01-01

    Background and purpose: 3,4-Methylenedioxymethamphetamine (MDMA) and cocaine are two widely abused psychostimulant drugs targeting the dopamine transporter (DAT). DAT availability regulates dopamine neurotransmission and uptake of MDMA-derived neurotoxic metabolites. We aimed to determine the effect of cocaine pre-exposure on the acute and long-term effects of MDMA in mice. Experimental approach: Mice received a course of cocaine (20 mgkg?1, 2 for 3 days) followed by MDMA (20 mgkg?1, 2, 3 h apart). Locomotor activity, extracellular dopamine levels and dopaminergic neurotoxicity were determined. Furthermore, following the course of cocaine, DAT density in striatal plasma membrane and endosome fractions was measured. Key results: Four days after the course of cocaine, challenge with MDMA attenuated the MDMA-induced striatal dopaminergic neurotoxicity. Co-administration of the protein kinase C (PKC) inhibitor NPC 15437 prevented cocaine protection. At the same time, after the course of cocaine, DAT density was reduced in the plasma membrane and increased in the endosome fraction, and this effect was prevented by NPC 15437. The course of cocaine potentiated the MDMA-induced increase in extracellular dopamine and locomotor activity, following challenge 4 days later, compared with those pretreated with saline. Conclusions and implications: Repeated cocaine treatment followed by withdrawal protected against MDMA-induced dopaminergic neurotoxicity by internalizing DAT via a mechanism which may involve PKC. Furthermore, repeated cocaine followed by withdrawal induced behavioural and neurochemical sensitization to MDMA, measures which could be indicative of increased rewarding effects of MDMA. PMID:20015297

  7. Reduced Dopamine Transporter Functioning Induces High-Reward Risk-Preference Consistent with Bipolar Disorder

    PubMed Central

    van Enkhuizen, Jordy; Henry, Brook L; Minassian, Arpi; Perry, William; Milienne-Petiot, Morgane; Higa, Kerin K; Geyer, Mark A; Young, Jared W

    2014-01-01

    Individuals with bipolar disorder (BD) exhibit deleterious decision making, negatively impacting their lives. Such aberrant decision making can be quantified using the Iowa Gambling Task (IGT), which requires choosing between advantageous and disadvantageous options based on different reward/punishment schedules. The mechanisms underlying this behavioral deficit are unknown, but may include the reduced dopamine transporter (DAT) functioning reported in BD patients. Using both human and mouse IGTs, we tested whether reduced DAT functioning would recreate patterns of deficient decision making of BD patients. We assessed the IGT performance of 16 BD subjects (7 female) and 17 healthy control (HC) subjects (12 female). We recorded standard IGT performance measures and novel post-reward and post-punishment decision-making strategies. We characterized a novel single-session mouse IGT using C57BL/6J mice (n=44). The BD and HC IGT performances were compared with the effects of chronic (genetic knockdown (KD; n=31) and wild-type (n=28) mice) and acute (C57BL/6J mice (n=89) treated with the DAT inhibitor GBR12909) reductions of DAT functioning in mice performing this novel IGT. BD patients exhibited impaired decision making compared with HC subjects. Both the good-performing DAT KD and GBR12909-treated mice exhibited poor decision making in the mouse IGT. The deficit of each population was driven by high-reward sensitivity. The single-session mouse IGT measures dynamic risk-based decision making similar to humans. Chronic and acute reductions of DAT functioning in mice impaired decision-making consistent with poor IGT performance of BD patients. Hyperdopaminergia caused by reduced DAT may impact poor decision making in BD patients, which should be confirmed in future studies. PMID:25005251

  8. Reduced dopamine transporter functioning induces high-reward risk-preference consistent with bipolar disorder.

    PubMed

    van Enkhuizen, Jordy; Henry, Brook L; Minassian, Arpi; Perry, William; Milienne-Petiot, Morgane; Higa, Kerin K; Geyer, Mark A; Young, Jared W

    2014-12-01

    Individuals with bipolar disorder (BD) exhibit deleterious decision making, negatively impacting their lives. Such aberrant decision making can be quantified using the Iowa Gambling Task (IGT), which requires choosing between advantageous and disadvantageous options based on different reward/punishment schedules. The mechanisms underlying this behavioral deficit are unknown, but may include the reduced dopamine transporter (DAT) functioning reported in BD patients. Using both human and mouse IGTs, we tested whether reduced DAT functioning would recreate patterns of deficient decision making of BD patients. We assessed the IGT performance of 16 BD subjects (7 female) and 17 healthy control (HC) subjects (12 female). We recorded standard IGT performance measures and novel post-reward and post-punishment decision-making strategies. We characterized a novel single-session mouse IGT using C57BL/6J mice (n = 44). The BD and HC IGT performances were compared with the effects of chronic (genetic knockdown (KD; n = 31) and wild-type (n = 28) mice) and acute (C57BL/6J mice (n = 89) treated with the DAT inhibitor GBR12909) reductions of DAT functioning in mice performing this novel IGT. BD patients exhibited impaired decision making compared with HC subjects. Both the good-performing DAT KD and GBR12909-treated mice exhibited poor decision making in the mouse IGT. The deficit of each population was driven by high-reward sensitivity. The single-session mouse IGT measures dynamic risk-based decision making similar to humans. Chronic and acute reductions of DAT functioning in mice impaired decision-making consistent with poor IGT performance of BD patients. Hyperdopaminergia caused by reduced DAT may impact poor decision making in BD patients, which should be confirmed in future studies. PMID:25005251

  9. Dopamine D3 receptor antagonist SB-277011A inhibits methamphetamine self-administration and methamphetamine-induced reinstatement of drug-seeking in rats

    PubMed Central

    Higley, Amanda E.; Kiefer, Stephen W.; Li, Xia; Gal, Jzsef; Xi, Zheng-Xiong; Gardner, Eliot L.

    2013-01-01

    We have previously reported that selective blockade of brain dopamine D3 receptors by SB-277011A significantly attenuates cocaine self-administration and cocaine-induced reinstatement of drug-seeking behavior. In the present study, we investigated whether SB-277011A similarly inhibits methamphetamine self-administration and methamphetamine-induced reinstatement to drug-seeking behavior. Male LongEvans rats were allowed to intravenously self-administer methamphetamine (0.05 mg/kg/infusion) under fixed-ratio 2 (FR2) or progressive-ratio (PR) reinforcement conditions, and some rats were tested for methamphetamine-induced reinstatement of drug-seeking behavior after extinction of self-administration. The effects of SB-277011A on each of these methamphetamine-supported behaviors were then tested. Acute intraperitoneal (i.p.) administration of SB-277011A failed to alter methamphetamine self-administration under FR2 reinforcement, but significantly lowered the break-point for methamphetamine self-administration under PR reinforcement. SB-277011A also significantly inhibited methamphetamine-triggered reinstatement of extinguished drug-seeking behavior. Overall, these data show that blockade of dopamine D3 receptors by SB-277011A attenuates the rewarding and incentive motivational effects of methamphetamine in rats, supporting the development of selective dopamine D3 antagonists for the treatment of methamphetamine addiction. PMID:21466803

  10. Methamphetamine-induced short-term increase and long-term decrease in spatial working memory affects protein Kinase M zeta (PKM?), dopamine, and glutamate receptors

    PubMed Central

    Braren, Stephen H.; Drapala, Damian; Tulloch, Ingrid K.; Serrano, Peter A.

    2014-01-01

    Methamphetamine (MA) is a toxic, addictive drug shown to modulate learning and memory, yet the neural mechanisms are not fully understood. We investigated the effects of 2 weekly injections of MA (30 mg/kg) on working memory using the radial 8-arm maze (RAM) across 5 weeks in adolescent-age mice. MA-treated mice show a significant improvement in working memory performance 1 week following the first MA injection compared to saline-injected controls. Following 5 weeks of MA abstinence mice were re-trained on a reference and working memory version of the RAM to assess cognitive flexibility. MA-treated mice show significantly more working memory errors without effects on reference memory performance. The hippocampus and dorsal striatum were assessed for expression of glutamate receptors subunits, GluA2 and GluN2B; dopamine markers, dopamine 1 receptor (D1), dopamine transporter (DAT) and tyrosine hydroxylase (TH); and memory markers, protein kinase M zeta (PKM?) and protein kinase C zeta (PKC?). Within the hippocampus, PKM? and GluA2 are both significantly reduced after MA supporting the poor memory performance. Additionally, a significant increase in GluN2B and decrease in D1 identifies dysregulated synaptic function. In the striatum, MA treatment increased cytosolic DAT and TH levels associated with dopamine hyperfunction. MA treatment significantly reduced GluN2B while increasing both PKM? and PKC? within the striatum. We discuss the potential role of PKM?/PKC? in modulating dopamine and glutamate receptors after MA treatment. These results identify potential underlying mechanisms for working memory deficits induced by MA. PMID:25566006

  11. Disruption of the mevalonate pathway induces dNTP depletion and DNA damage.

    PubMed

    Martn Snchez, Covadonga; Prez Martn, Jos Manuel; Jin, Jong-Sik; Dvalos, Alberto; Zhang, Wei; de la Pea, Gema; Martnez-Botas, Javier; Rodrguez-Acebes, Sara; Surez, Yajaira; Hazen, Mara Jos; Gmez-Coronado, Diego; Busto, Rebeca; Cheng, Yung-Chi; Lasuncin, Miguel A

    2015-09-01

    The mevalonate pathway is tightly linked to cell division. Mevalonate derived non-sterol isoprenoids and cholesterol are essential for cell cycle progression and mitosis completion respectively. In the present work, we studied the effects of fluoromevalonate, a competitive inhibitor of mevalonate diphosphate decarboxylase, on cell proliferation and cell cycle progression in both HL-60 and MOLT-4 cells. This enzyme catalyzes the synthesis of isopentenyl diphosphate, the first isoprenoid in the cholesterol biosynthesis pathway, consuming ATP at the same time. Inhibition of mevalonate diphosphate decarboxylase was followed by a rapid accumulation of mevalonate diphosphate and the reduction of ATP concentrations, while the cell content of cholesterol was barely affected. Strikingly, mevalonate diphosphate decarboxylase inhibition also resulted in the depletion of dNTP pools, which has never been reported before. These effects were accompanied by inhibition of cell proliferation and cell cycle arrest at S phase, together with the appearance of ?-H2AX foci and Chk1 activation. Inhibition of Chk1 in cells treated with fluoromevalonate resulted in premature entry into mitosis and massive cell death, indicating that the inhibition of mevalonate diphosphate decarboxylase triggered a DNA damage response. Notably, the supply of exogenously deoxyribonucleosides abolished ?-H2AX formation and prevented the effects of mevalonate diphosphate decarboxylase inhibition on DNA replication and cell growth. The results indicate that dNTP pool depletion caused by mevalonate diphosphate decarboxylase inhibition hampered DNA replication with subsequent DNA damage, which may have important consequences for replication stress and genomic instability. PMID:26055626

  12. PTEN ELEVATION, AUTOPHAGY AND METABOLIC REPROGRAMMING MAY BE INDUCED IN HUMAN CHONDROCYTES DURING STEROIDS OR NUTRIENT DEPLETION AND OSTEOARTHRITIS.

    PubMed

    Galasso, O; Panza, S; Santoro, M; Goldring, M B; Aquila, S; Gasparini, G

    2015-01-01

    The exact mechanisms controlling the development and progression of osteoarthritis have not yet been clarified. Our aim was to investigate new pathomechanisms, with an emphasis on novel molecular targets that might regulate human chondrocytes in osteoarthritis. As a model for studying cell survival and metabolism, C-28/I2 and T/C-28a4 human chondrocytes were grown in complete medium, in dex-tran-coated charcoal treated medium and in serum-free medium. Healthy and osteoarthritic human cartilage samples were obtained from discarded surgical material. Cell survival, PTEN, AKT, Beclin1, AMBRA, AMPK and glucose/triglyceride metabolism were evaluated by immunoblotting and spectro-photometric assays. Starvation and steroids depletion decreased cell survival concomitantly with PTEN elevation, repression of the PI3K/AKT signaling axis and autophagy activation. These experimental conditions promoted the accumulation of glucose, decreased levels of G6PDH and resulted in differen-tial expression of OXPHOS complexes. Furthermore, they induced the expression of AMPK, reduced triglyceride levels and increased lipase activity, which was accompanied by a change in chondrocytes toward a fibroblast-like morphology. In osteoarthritic human cartilage, increased PTEN, AMPK and autophagy reflected the chondrocyte responses observed during starvation and steroids depletion. In conclusion, we defined the metabolic phenotype of human chondrocytes, in which both starvation and steroids depletion induce the activation of PTEN, AMPK and autophagy signaling, concomitant with metabolic reprogramming. Our data may aid in the development of novel in vitro models for the discovery and design of drugs or nutraceuticals capable of ameliorating the course of osteoarthritis. PMID:26652486

  13. Antagonist-induced conformational changes in dopamine transporter extracellular loop two involve residues in a potential salt bridge.

    PubMed

    Gaffaney, Jon D; Shetty, Madhur; Felts, Bruce; Pramod, Akula-Bala; Foster, James D; Henry, L Keith; Vaughan, Roxanne A

    2014-07-01

    Ligand-induced changes in the conformation of extracellular loop (EL) 2 in the rat (r) dopamine transporter (DAT) were examined using limited proteolysis with endoproteinase Asp-N and detection of cleavage products by epitope-specific immunoblotting. The principle N-terminal fragment produced by Asp-N was a 19kDa peptide likely derived by proteolysis of EL2 residue D174, which is present just past the extracellular end of TM3. Production of this fragment was significantly decreased by binding of cocaine and other uptake blockers, but was not affected by substrates or Zn(2+), indicating the presence of a conformational change at D174 that may be related to the mechanism of transport inhibition. DA transport activity and cocaine analog binding were decreased by Asp-N treatment, suggesting a requirement for EL2 integrity in these DAT functions. In a previous study we demonstrated that ligand-induced protease resistance also occurred at R218 on the C-terminal side of rDAT EL2. Here using substituted cysteine accessibility analysis of human (h) DAT we confirm cocaine-induced alterations in reactivity of the homologous R219 and identify conformational sensitivity of V221. Focused molecular modeling of D174 and R218 based on currently available Aquifex aeolicus leucine transporter crystal structures places these residues within 2.9 of one another, suggesting their proximity as a structural basis for their similar conformational sensitivities and indicating their potential to form a salt bridge. These findings extend our understanding of DAT EL2 and its role in transport and binding functions. PMID:24269640

  14. Antagonist-Induced Conformational Changes in Dopamine Transporter Extracellular Loop Two Involve Residues in a Potential Salt Bridge

    PubMed Central

    Gaffaney, Jon D.; Shetty, Madhur; Felts, Bruce; Pramod, Akula-Bala; Foster, James D.; Henry, L. Keith; Vaughan, Roxanne A.

    2014-01-01

    Ligand-induced changes in the conformation of extracellular loop (EL) 2 in the rat (r) dopamine transporter (DAT) were examined using limited proteolysis with endoproteinase Asp-N and detection of cleavage products by epitope-specific immunoblotting. The principle N-terminal fragment produced by Asp-N was a 19 kDa peptide likely derived by proteolysis of EL2 residue D174, which is present just past the extracellular end of TM3. Production of this fragment was significantly decreased by binding of cocaine and other uptake blockers, but was not affected by substrates or Zn2+, indicating the presence of a conformational change at D174 that may be related to the mechanism of transport inhibition. DA transport activity and cocaine analog binding were decreased by Asp-N treatment, suggesting a requirement for EL2 integrity in these DAT functions. In a previous study we demonstrated that ligand-induced protease resistance also occurred at R218 on the C-terminal side of rDAT EL2. Here using substituted cysteine accessibility analysis of human (h) DAT we confirm cocaine-induced alterations in reactivity of the homologous R219 and identify conformational sensitivity of V221. Focused molecular modeling of D174 and R218 based on currently available Aquifex aeolicus leucine transporter crystal structures places these residues within 2.9 Å of one another, suggesting their proximity as a structural basis for their similar conformational sensitivities and indicating their potential to form a salt bridge. These findings extend our understanding of DAT EL2 and its role in transport and binding functions. PMID:24269640

  15. Dopamine Activity in the Lateral Anterior Hypothalamus Modulates Aas-Induced Aggression through D2 but not D5 Receptors

    PubMed Central

    Schwartzer, Jared J.; Melloni, Richard H.

    2011-01-01

    Treatment with anabolic-androgenic steroids (AAS) throughout adolescence facilitates offensive aggression in Syrian hamsters. In the anterior hypothalamus (AH), the dopaminergic neural system undergoes alterations after repeated exposure to AAS producing elevated aggression. Previously, systemic administration of selective dopamine receptor antagonists has been shown to reduce aggression in various species and animal models. However, these reductions in aggression occur with concomitant alterations in general arousal and mobility. Therefore, in order to control for these systemic effects, the current studies utilized microinjection techniques to determine the effects of local antagonism of D2 and D5 receptors in the AH on adolescent AAS-induced aggression. Male Syrian hamsters were treated with AAS throughout adolescence and tested for aggression after local infusion of the D2 antagonist eticlopride, or the D5 antagonist SCH-23390, into the AH. Treatment with eticlopride showed dose-dependent suppression of aggressive behavior in the absence of changes in mobility. Conversely, while injection of SCH-23390 suppressed aggressive behavior, these reductions were met with alterations in social interest and locomotor behavior. To elucidate a plausible mechanism for the observed D5 receptor mediation of AAS-induced aggression, brains of AAS and sesame oil-treated animals were processed for double-label immunofluorescence of GAD67 (a marker for GABA production) and D5 receptors in the lateral subdivision of the AH (LAH). Results indicate a sparse distribution of GAD67 neurons colocalized with D5 receptors in the LAH. Together, these results indicate that D5 receptors in the LAH modulate non-GABAergic pathways that indirectly influence aggression control, while D2 receptors have a direct influence on AAS-induced aggression. PMID:20939664

  16. Isoflurane anesthesia inhibits clozapine- and risperidone-induced dopamine release and anesthesia-induced changes in dopamine metabolism was modified by fluoxetine in the rat striatum: an in vivo microdialysis study.

    PubMed

    Adachi, Yushi U; Yamada, Shigeyuki; Satomoto, Maiko; Higuchi, Hideyuki; Watanabe, Kazuhiko; Kazama, Tomiei; Mimuro, Soichiro; Sato, Shigehito

    2008-02-01

    Previously, we have reported that halothane anesthesia increases the extracellular concentrations of dopamine (DA) metabolites in the rat striatum using in vivo microdialysis techniques, and we have suggested that volatile anesthetics affect DA release and metabolism in various ways. The present investigation assesses the effect of isoflurane, widely used in clinical anesthesia, on DA release and metabolism. A microdialysis probe was implanted in the striatum of male Sprague-Dawley rats (n=5-7 per group). After recovery, the probe was perfused with modified Ringer's solution and 40 microl of dialysate were injected into a high performance liquid chromatograph every 20 min. The rats were given saline or the same volume of 10 mg kg(-1) clozapine, risperidone, fluoxetine or citalopram. After the pharmacological treatment, the rats were anesthetized with 1.0% or 2.5% isoflurane for 1h. The data were analyzed using two-way analysis of variance (ANOVA). For each drug with significant (p<0.05) drug-time interactions, the statistical analysis included one-way ANOVA and Newman-Keuls post hoc comparisons. A high concentration of isoflurane (2.5%) anesthesia increased the extracellular concentration of DA metabolites during emergence from anesthesia. The levels of DA metabolites increased in an isoflurane concentration-dependent manner. Isoflurane attenuated DA release induced by clozapine and risperidone. Fluoxetine, but not citalopram, antagonized the isoflurane-induced increase in metabolites. The results of current investigation suggest that isoflurane enhances presynaptic DA metabolism, and that the oxidation of DA might be partially modulated by the activities of the dopaminergic-serotonergic pathway at a presynaptic site in the rat striatum. PMID:17719143

  17. Oxytocin Reverses Amphetamine-Induced Deficits in Social Bonding: Evidence for an Interaction with Nucleus Accumbens Dopamine

    PubMed Central

    Liu, Yan; Gobrogge, Kyle L.; Wang, Hui

    2014-01-01

    Drug addiction has devastating consequences on social behaviors and can lead to the impairment of social bonding. Accumulating evidence indicates that alterations in oxytocin (OT) and dopamine (DA) neurotransmission within brain reward circuitry may be involved. We investigated this possibility, as well as the therapeutic potential of OT for drug-induced social deficits, using the prairie vole (Microtus ochrogaster)a socially monogamous rodent that forms enduring pair bonds between adult mates. We demonstrate that repeated exposure to the commonly abused psychostimulant amphetamine (AMPH) inhibits the formation of partner preferences (an index of pair bonding) in female prairie voles. AMPH exposure also altered OT and DA neurotransmission in regions that mediate partner preference formation: it decreased OT and DA D2 receptor immunoreactivity in the medial prefrontal cortex (mPFC) and nucleus accumbens (NAcc), respectively, and increased NAcc DA levels. Administration of OT directly into the mPFC of AMPH-exposed voles restored partner preferences, and altered NAcc DA levels, and this effect was dependent on OT receptor activation. Together, these data suggest that repeated AMPH exposure impairs pair bonding through an OT-mediated mechanism, and that OT and DA systems within brain reward circuitry may interact to mediate the complex relationship between drug abuse and social bonding. Further, these results provide empirical support for the idea that the central OT system may represent an important target for the treatment of social deficits in addiction. PMID:24948805

  18. Dopamine D2 Receptor Is Involved in Alleviation of Type II Collagen-Induced Arthritis in Mice

    PubMed Central

    Lu, Jian-Hua; Liu, Yi-Qian; Deng, Qiao-Wen; Peng, Yu-Ping; Qiu, Yi-Hua

    2015-01-01

    Human and murine lymphocytes express dopamine (DA) D2-like receptors including DRD2, DRD3, and DRD4. However, their roles in rheumatoid arthritis (RA) are less clear. Here we showed that lymphocyte DRD2 activation alleviates both imbalance of T-helper (Th)17/T-regulatory (Treg) cells and inflamed symptoms in a mouse arthritis model of RA. Collagen-induced arthritis (CIA) was prepared by intradermal injection of chicken collagen type II (CII) in tail base of DBA/1 mice or Drd2?/? C57BL/6 mice. D2-like receptor agonist quinpirole downregulated expression of proinflammatory Th17-related cytokines interleukin- (IL-) 17 and IL-22 but further upregulated expression of anti-inflammatory Treg-related cytokines transforming growth factor- (TGF-) ? and IL-10 in lymphocytes in vitro and in ankle joints in vivo in CIA mice. Quinpirole intraperitoneal administration reduced both clinical arthritis score and serum anti-CII IgG level in CIA mice. However, Drd2?/? CIA mice manifested more severe limb inflammation and higher serum anti-CII IgG level and further upregulated IL-17 and IL-22 expression and downregulated TGF-? and IL-10 expression than wild-type CIA mice. In contrast, Drd1?/? CIA mice did not alter limb inflammation or anti-CII IgG level compared with wild-type CIA mice. These results suggest that DRD2 activation is involved in alleviation of CIA symptoms by amelioration of Th17/Treg imbalance. PMID:26693483

  19. Dopamine D2 Receptor Is Involved in Alleviation of Type II Collagen-Induced Arthritis in Mice.

    PubMed

    Lu, Jian-Hua; Liu, Yi-Qian; Deng, Qiao-Wen; Peng, Yu-Ping; Qiu, Yi-Hua

    2015-01-01

    Human and murine lymphocytes express dopamine (DA) D2-like receptors including DRD2, DRD3, and DRD4. However, their roles in rheumatoid arthritis (RA) are less clear. Here we showed that lymphocyte DRD2 activation alleviates both imbalance of T-helper (Th)17/T-regulatory (Treg) cells and inflamed symptoms in a mouse arthritis model of RA. Collagen-induced arthritis (CIA) was prepared by intradermal injection of chicken collagen type II (CII) in tail base of DBA/1 mice or Drd2 (-/-) C57BL/6 mice. D2-like receptor agonist quinpirole downregulated expression of proinflammatory Th17-related cytokines interleukin- (IL-) 17 and IL-22 but further upregulated expression of anti-inflammatory Treg-related cytokines transforming growth factor- (TGF-) ? and IL-10 in lymphocytes in vitro and in ankle joints in vivo in CIA mice. Quinpirole intraperitoneal administration reduced both clinical arthritis score and serum anti-CII IgG level in CIA mice. However, Drd2 (-/-) CIA mice manifested more severe limb inflammation and higher serum anti-CII IgG level and further upregulated IL-17 and IL-22 expression and downregulated TGF-? and IL-10 expression than wild-type CIA mice. In contrast, Drd1 (-/-) CIA mice did not alter limb inflammation or anti-CII IgG level compared with wild-type CIA mice. These results suggest that DRD2 activation is involved in alleviation of CIA symptoms by amelioration of Th17/Treg imbalance. PMID:26693483

  20. PKA-mediated responses in females' estrous cycle affect cocaine-induced responses in dopamine-mediated intracellular cascades.

    PubMed

    Weiner, J; Sun, W Lun; Zhou, L; Kreiter, C M; Jenab, S; Quiñones-Jenab, V

    2009-07-01

    An extensive body of literature provides evidence for both sexual dimorphism and menstrual cycle effects in drug abuse patterns and behavioral responses. However, the cellular mechanisms underlying sexually dimorphic responses to and hormonal effects on cocaine use remain unclear. We hypothesized that endogenous hormonal fluctuations during the estrous cycle of rats modulate cocaine's effects on dopamine- and PKA-mediated intracellular responses. To test this hypothesis, intact female rats at different stages of their cycle received a single injection of saline or cocaine (20 mg/kg) and were sacrificed after 15 or 60 min. The nucleus accumbens (NAc) and caudate putamen (CPu) were dissected and analyzed via Western blot for total and phosphorylated (p-thr34) dopamine- and 3'-5'-cyclic AMP-regulated phosphoprotein with molecular weight 32 kDa (DARPP-32), PP1, PP2B (CNA1 and CNB1 subunits), PKA, CREB, cFOS, and Delta-FosB. Our results show that saline-treated rats had estrous cycle-related differences in protein levels of pCREB, DARPP-32, p-thr34-DARPP-32, PP1, and CNA1. Saline-treated female rats in the estrus stage had higher levels of pCREB in the NAc, but cocaine-treatment lowered pCREB levels. The estrous cycle also significantly affected the magnitude of change for p-thr34-DARPP-32 protein levels in both the NAc and CPu. Sixty minutes of cocaine administration increased p-thr34-DARPP-32 levels in the NAc of rats during estrus and proestrus and in the CPu of rats in diestrus. Furthermore, cocaine-induced changes in PP1 protein levels in the NAc were also affected by the stage of the cycle; 60 min of cocaine administration increased PP1 levels in the NAc of rats during diestrus, whereas PP-1 levels decreased in rats during estrus. Taken together, these novel findings suggest that hormonal fluctuations during the estrous cycle may contribute to the previously reported sex differences in the PKA pathway and in behavioral responses to cocaine. PMID:19348873

  1. Temperature dependence of the radiation induced change of depletion voltage in silicon PIN detectors

    SciTech Connect

    Ziock, H.J.; Holzscheiter, K.; Morgan, A.; Palounek, A.P.T.; Ellison, J.; Heinson, A.P.; Mason, M.; Wimpenny, S.J.; Barberis, E.; Cartiglia, N.; Grillo, A.; O`Shaughnessy, K.; Rahn, J.; Rinaldi, P.; Rowe, W.A.; Sadrozinski, H.F.W.; Seiden, A.; Spencer, E.; Webster, A.; Wichmann, R.; Wilder, M.; Frautschi, M.A.; Matthews, J.A.J.; McDonald, D.; Skinner, D.; Coupal, D.; Pal, T.

    1993-11-01

    The silicon microstrip detectors that will be used in the SDC experiment at the Superconducting Super Collider (SSC) will be exposed to very large fluences of charged particles, neutrons, and gammas. The authors present a study of how temperature affects the change in the depletion voltage of silicon PIN detectors damaged by radiation. They study the initial radiation damage and the short-term and long-term annealing of that damage as a function of temperature in the range from {minus}10{degrees}C to +50{degrees}C, and as a function of 800 MeV proton fluence up to 1.5 {times} 10{sup 14} p/cm{sup 2}. They express the pronounced temperature dependencies in a simple model in terms of two annealing time constants which depend exponentially on the temperature.

  2. Considerations for evaluating ultraviolet radiation-induced genetic damage relative to Antarctic ozone depletion.

    PubMed Central

    Karentz, D

    1994-01-01

    Springtime ozone depletion over the Antarctic results in increased UVB in local marine environments. It has been established that decreases in primary productivity occur with decreases in ozone concentrations, but the impact of increased UVB on the functioning and stability of the ecosystem has not yet been determined. Very little has been done to evaluate the potential for genetic damage caused by the increase in UVB, and this type of damage is most significant relative to the fitness and maintenance of populations. An essential problem in evaluating genotoxic effects is the lack of appropriate techniques to sample and quantify genetic damage in field populations under ambient UVB levels. In addition, it is currently not feasible to estimate exposure levels for organisms in their natural habitats. PMID:7713036

  3. Intracellular Metabolite Pool Changes in Response to Nutrient Depletion Induced Metabolic Switching in Streptomyces coelicolor.

    PubMed

    Wentzel, Alexander; Sletta, Havard; Consortium, Stream; Ellingsen, Trond E; Bruheim, Per

    2012-01-01

    A metabolite profiling study of the antibiotic producing bacterium Streptomyces coelicolor A3(2) has been performed. The aim of this study was to monitor intracellular metabolite pool changes occurring as strains of S. coelicolor react to nutrient depletion with metabolic re-modeling, so-called metabolic switching, and transition from growth to secondary metabolite production phase. Two different culture media were applied, providing depletion of the key nutrients phosphate and L-glutamate, respectively, as the triggers for metabolic switching. Targeted GC-MS and LC-MS methods were employed to quantify important primary metabolite groups like amino acids, organic acids, sugar phosphates and other phosphorylated metabolites, and nucleotides in time-course samples withdrawn from fully-controlled batch fermentations. A general decline, starting already in the early growth phase, was observed for nucleotide pools and phosphorylated metabolite pools for both the phosphate and glutamate limited cultures. The change in amino acid and organic acid pools were more scattered, especially in the phosphate limited situation while a general decrease in amino acid and non-amino organic acid pools was observed in the L-glutamate limited situation. A phoP deletion mutant showed basically the same metabolite pool changes as the wild-type strain M145 when cultivated on phosphate limited medium. This implies that the inactivation of the phoP gene has only little effect on the detected metabolite levels in the cell. The energy charge was found to be relatively constant during growth, transition and secondary metabolite production phase. The results of this study and the employed targeted metabolite profiling methodology are directly relevant for the evaluation of precursor metabolite and energy supply for both natural and heterologous production of secondary metabolites in S. coelicolor. PMID:24957373

  4. Intracellular Metabolite Pool Changes in Response to Nutrient Depletion Induced Metabolic Switching in Streptomyces coelicolor

    PubMed Central

    Wentzel, Alexander; Sletta, Havard; Consortium, Stream; Ellingsen, Trond E.; Bruheim, Per

    2012-01-01

    A metabolite profiling study of the antibiotic producing bacterium Streptomyces coelicolor A3(2) has been performed. The aim of this study was to monitor intracellular metabolite pool changes occurring as strains of S. coelicolor react to nutrient depletion with metabolic re-modeling, so-called metabolic switching, and transition from growth to secondary metabolite production phase. Two different culture media were applied, providing depletion of the key nutrients phosphate and L-glutamate, respectively, as the triggers for metabolic switching. Targeted GC-MS and LC-MS methods were employed to quantify important primary metabolite groups like amino acids, organic acids, sugar phosphates and other phosphorylated metabolites, and nucleotides in time-course samples withdrawn from fully-controlled batch fermentations. A general decline, starting already in the early growth phase, was observed for nucleotide pools and phosphorylated metabolite pools for both the phosphate and glutamate limited cultures. The change in amino acid and organic acid pools were more scattered, especially in the phosphate limited situation while a general decrease in amino acid and non-amino organic acid pools was observed in the L-glutamate limited situation. A phoP deletion mutant showed basically the same metabolite pool changes as the wild-type strain M145 when cultivated on phosphate limited medium. This implies that the inactivation of the phoP gene has only little effect on the detected metabolite levels in the cell. The energy charge was found to be relatively constant during growth, transition and secondary metabolite production phase. The results of this study and the employed targeted metabolite profiling methodology are directly relevant for the evaluation of precursor metabolite and energy supply for both natural and heterologous production of secondary metabolites in S. coelicolor. PMID:24957373

  5. Nicotinic and dopamine D2 receptors mediate nicotine-induced changes in ventral tegmental area neurotensin system

    PubMed Central

    Alburges, Mario E.; Hoonakker, Amanda J.; Hanson, Glen R.

    2009-01-01

    Neuropeptides have been implicated in the psychopathology of stimulants of abuse. Neurotensin is a neuropeptide associated with the regulation of the nigrostriatal and mesolimbic dopamine pathways. In addition, the ventral tegmental area, a midbrain region implicated in the rewarding effects of most, if not all, addictive drugs, appears to be a particularly critical target for nicotine action. Because neurotensin has been linked with both mesolimbic and mesocortical dopamine function, we examined the impact of nicotine treatment on central nervous neurotensin systems by measuring changes in neurotensin tissue content because it has been shown such changes reflect alterations in release and activity of this peptide system. Male Sprague-Dawley rats received multiple administrations of () nicotine 4.0 mg/kg/day (0.8 mg/kg, i.p.; 5 2-h intervals) in the presence or absence of selective dopamine receptor antagonists (dopamine D1; SCH23390 or dopamine D2; eticlopride) or two doses of the non-selective nicotinic acetylcholine receptor antagonist (mecamylamine; 3.0 and 6.0 mg/kg, s.c.). The nicotine treatment significantly decreased neurotensin-like immunoreactivity content in the ventral tegmental area, as well as related regions such as prefrontal cortex, substantia nigra, and anterior striatal region 1218 h after drug treatment, but not the nucleus accumbens. The nicotine-mediated decrease in the neurotensin-like immunoreactivity of the ventral tegmental area was selectively blocked by a specific dopamine D2, but not a dopamine D1, receptor antagonist, while mecamylamine attenuated at the low (3.0 mg/kg) and completely blocked at high (6.0 mg/kg) dose this nicotine effect. These findings with previous studies, suggest that nicotine-mediated dopamine release activates D2 receptors which in turn increases neurotensin release, turnover and acutely reduces tissue levels in the ventral tegmental area and other limbic and basal ganglia structures. PMID:17689525

  6. Apoptosis induced by NAD depletion is inhibited by KN-93 in a CaMKII-independent manner.

    PubMed

    Takeuchi, Mikio; Yamamoto, Tomoko

    2015-07-01

    Nicotinamide phosphoribosyltransferase (NAMPT) is a key enzyme that catalyzes the synthesis of nicotinamide mononucleotide from nicotinamide (Nam) in the salvage pathway of mammalian NAD biosynthesis. Several potent NAMPT inhibitors have been identified and used to investigate the role of intracellular NAD and to develop therapeutics. NAD depletion induced by NAMPT inhibitors depolarizes mitochondrial membrane potential and causes apoptosis in a range of cell types. However, the mechanisms behind this depolarization have not been precisely elucidated. We observed that apoptosis of THP-1 cells in response to NAMPT inhibitors was reduced by the Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) inhibitor KN-93 via an unknown mechanism. The inactive analog of KN-93, KN-92, exhibited the same activity, but the CaMKII-inhibiting cell-permeable autocamtide-2-related inhibitory peptide II did not, indicating that the inhibition of THP-1 cell apoptosis was not dependent on CaMKII. In evaluating the mechanism of action, we confirmed that KN-93 did not inhibit decreases in NAD levels but did inhibit decreases in mitochondrial membrane potential, indicating that KN-93 exerts inhibition upstream of the mitochondrial pathway of apoptosis. Further, qPCR analysis of the Bcl-2 family of proteins showed that Bim is efficiently expressed following NAMPT inhibition and that KN-92 did not inhibit this expression. The L-type Ca(2+) channel blockers verapamil and nimodipine partially inhibited apoptosis, indicating that part of this effect is dependent on Ca(2+) channel inhibition, as both KN-93 and KN-92 are reported to inhibit L-type Ca(2+) channels. On the other hand, KN-93 and KN-92 did not markedly inhibit apoptosis induced by anti-cancer agents such as etoposide, actinomycin D, ABT-737, or TW-37, indicating that the mechanism of inhibition is specific to apoptosis induced by NAD depletion. These results demonstrate that NAD depletion induces a specific type of apoptosis that is effectively inhibited by the KN-93 series of compounds. PMID:26024774

  7. Dopamine D2 Antagonist-Induced Striatal Nur77 Expression Requires Activation of mGlu5 Receptors by Cortical Afferents

    PubMed Central

    Maheux, Jérôme; St-Hilaire, Michel; Voyer, David; Tirotta, Emanuele; Borrelli, Emiliana; Rouillard, Claude; Rompré, Pierre-Paul; Lévesque, Daniel

    2012-01-01

    Dopamine D2 receptor antagonists modulate gene transcription in the striatum. However, the molecular mechanism underlying this effect remains elusive. Here we used the expression of Nur77, a transcription factor of the orphan nuclear receptor family, as readout to explore the role of dopamine, glutamate, and adenosine receptors in the effect of a dopamine D2 antagonist in the striatum. First, we investigated D2 antagonist-induced Nur77 mRNA in D2L receptor knockout mice. Surprisingly, deletion of the D2L receptor isoform did not reduce eticlopride-induced upregulation of Nur77 mRNA levels in the striatum. Next, we tested if an ibotenic acid-induced cortical lesion could block the effect of eticlopride on Nur77 expression. Cortical lesions strongly reduced eticlopride-induced striatal upregulation of Nur77 mRNA. Then, we investigated if glutamatergic neurotransmission could modulate eticlopride-induced Nur77 expression. A combination of a metabotropic glutamate type 5 (mGlu5) and adenosine A2A receptor antagonists abolished eticlopride-induced upregulation of Nur77 mRNA levels in the striatum. Direct modulation of Nur77 expression by striatal glutamate and adenosine receptors was confirmed using corticostriatal organotypic cultures. Taken together, these results indicate that blockade of postsynaptic D2 receptors is not sufficient to trigger striatal transcriptional activity and that interaction with corticostriatal presynaptic D2 receptors and subsequent activation of postsynaptic glutamate and adenosine receptors in the striatum is required. Thus, these results uncover an unappreciated role of presynaptic D2 heteroreceptors and support a prominent role of glutamate in the effect of D2 antagonists. PMID:22912617

  8. Methamphetamine-Induced Dopamine Transporter Complex Formation and Dopaminergic Deficits: The Role of D2 Receptor Activation

    PubMed Central

    Hadlock, Gregory C.; Chu, Pei-Wen; Walters, Elliot T.; Hanson, Glen R.

    2010-01-01

    Methamphetamine (METH) abuse is a serious public health issue. Of particular concern are findings that repeated high-dose administrations of METH cause persistent dopaminergic deficits in rodents, nonhuman primates, and humans. Previous studies have also revealed that METH treatment causes alterations in the dopamine transporter (DAT), including the formation of higher molecular mass DAT-associated complexes. The current study extends these findings by examining mechanisms underlying DAT complex formation. The association among DAT complex formation and other METH-induced phenomena, including alterations in vesicular monoamine transporter 2 (VMAT2) immunoreactivity, astrocytic activation [as assessed by increased glial fibrillary acidic protein (GFAP) immunoreactivity], and persistent dopaminergic deficits was also explored. Results revealed that METH-induced DAT complex formation and reductions in VMAT2 immunoreactivity precede increases in GFAP immunoreactivity. Furthermore, and as reported previously for DAT complexes, pretreatment with the D2 receptor antagonist eticlopride [S-(?)-3-chloro-5-ethyl-N-[(1-ethyl-2-pyrrolidinyl)methyl]-6-hydroxy-2-methoxybenzamide hydrochloride] attenuated the decrease in VMAT2 immunoreactivity as assessed 24 h after METH treatment. DAT complexes distinct from those present 24 h after METH treatment, decreases in VMAT2 immunoreactivity, and increased GFAP immunoreactivity were present 48 to 72 h after METH treatment. Pretreatment with eticlopride attenuated each of these phenomena. Finally, DAT complexes were present 7 days after METH treatment, a time point at which VMAT2 and DAT monomer immunoreactivity were also reduced. Eticlopride pretreatment attenuated each of these phenomena. These findings provide novel insight into not only receptor-mediated mechanisms underlying the effects of METH but also the interaction among factors that probably are associated with the persistent dopaminergic deficits caused by the stimulant. PMID:20622144

  9. Trafficking of Na-K-ATPase and dopamine receptor molecules induced by changes in intracellular sodium concentration of renal epithelial cells.

    PubMed

    Cinelli, Angel R; Efendiev, Riad; Pedemonte, Carlos H

    2008-10-01

    Most of the transepithelial transport of sodium in proximal tubules occurs through the coordinated action of the apical sodium/proton exchanger and the basolateral Na-K-ATPase. Hormones that regulate proximal tubule sodium excretion regulate the activities of these proteins. We have previously demonstrated that the level of intracellular sodium concentration modulates the regulation of Na-K-ATPase activity by angiotensin II and dopamine. An increase of a few millimolars in intracellular sodium concentration leads to increased Na-K-ATPase activity without a statistically significant increase in the number of plasma membrane Na-K-ATPase molecules, as determined by cell surface protein biotinylation. Using total internal reflection fluorescence, we detected an increased number of Na-K-ATPase molecules in cytosolic compartments adjacent to the plasma membrane, suggesting that the increased intracellular sodium concentration induces a movement of Na-K-ATPase molecules toward the plasma membrane. While intracellular compartments containing Na-K-ATPase molecules are very close to the plasma membrane, compartments containing type 1 dopamine receptors (D1Rs) are distributed in different parts of the cell cytosol. Fluorescence determinations indicate that an increased intracellular sodium concentration induces the increased colocalization of dopamine receptors with Na-K-ATPase molecules in the region of the plasma membrane. We propose that under in vivo conditions, in response to a sodium load in the lumen of proximal tubules, an increased level of intracellular sodium in epithelial cells is an early event that triggers the cellular response that leads to dopamine inhibition of proximal tubule sodium reabsorption. PMID:18701625

  10. Serotonin Depletion Induces Waiting Impulsivity' on the Human Four-Choice Serial Reaction Time Task: Cross-Species Translational Significance

    PubMed Central

    Worbe, Yulia; Savulich, George; Voon, Valerie; Fernandez-Egea, Emilio; Robbins, Trevor W

    2014-01-01

    Convergent results from animal and human studies suggest that reducing serotonin neurotransmission promotes impulsive behavior. Here, serotonin depletion was induced by the dietary tryptophan depletion procedure (TD) in healthy volunteers to examine the role of serotonin in impulsive action and impulsive choice. We used a novel translational analog of a rodent 5-choice serial reaction time task (5-CSRTT) the human 4-CSRTTand a reward delay-discounting questionnaire to measure effects on these different forms of waiting impulsivity'. There was no effect of TD on impulsive choice as indexed by the reward delay-discounting questionnaire. However, TD significantly increased 4-CSRTT premature responses (or impulsive action), which is remarkably similar to the previous findings of effect of serotonin depletion on rodent 5-CSRTT performance. Moreover, the increased premature responding in TD correlated significantly with individual differences on the motor impulsivity subscale of the Barratt Impulsivity Scale. TD also improved the accuracy of performance and speeded responding, possibly indicating enhanced attention and reward processing. The results suggest: (i) the 4-CSRTT will be a valuable addition to the tests already available to measure impulsivity in humans in a direct translational analog of a test extensively used in rodents; (ii) TD in humans produces a qualitatively similar profile of effects to those in rodents (ie, enhancing premature responding), hence supporting the conclusion that TD in humans exerts at least some of its effects on central serotonin; and (iii) this manipulation of serotonin produces dissociable effects on different measures of impulsivity, suggesting considerable specificity in its modulatory role. PMID:24385133

  11. Serotonin depletion induces 'waiting impulsivity' on the human four-choice serial reaction time task: cross-species translational significance.

    PubMed

    Worbe, Yulia; Savulich, George; Voon, Valerie; Fernandez-Egea, Emilio; Robbins, Trevor W

    2014-05-01

    Convergent results from animal and human studies suggest that reducing serotonin neurotransmission promotes impulsive behavior. Here, serotonin depletion was induced by the dietary tryptophan depletion procedure (TD) in healthy volunteers to examine the role of serotonin in impulsive action and impulsive choice. We used a novel translational analog of a rodent 5-choice serial reaction time task (5-CSRTT)-- the human 4-CSRTT--and a reward delay-discounting questionnaire to measure effects on these different forms of 'waiting impulsivity'. There was no effect of TD on impulsive choice as indexed by the reward delay-discounting questionnaire. However, TD significantly increased 4-CSRTT premature responses (or impulsive action), which is remarkably similar to the previous findings of effect of serotonin depletion on rodent 5-CSRTT performance. Moreover, the increased premature responding in TD correlated significantly with individual differences on the motor impulsivity subscale of the Barratt Impulsivity Scale. TD also improved the accuracy of performance and speeded responding, possibly indicating enhanced attention and reward processing. The results suggest: (i) the 4-CSRTT will be a valuable addition to the tests already available to measure impulsivity in humans in a direct translational analog of a test extensively used in rodents; (ii) TD in humans produces a qualitatively similar profile of effects to those in rodents (ie, enhancing premature responding), hence supporting the conclusion that TD in humans exerts at least some of its effects on central serotonin; and (iii) this manipulation of serotonin produces dissociable effects on different measures of impulsivity, suggesting considerable specificity in its modulatory role. PMID:24385133

  12. Sex differences in body fluid homeostasis: Sex chromosome complement influences on bradycardic baroreflex response and sodium depletion induced neural activity.

    PubMed

    Vivas, L; Dadam, F M; Caeiro, X E

    2015-12-01

    Clinical and basic findings indicate that angiotensin II (ANG II) differentially modulates hydroelectrolyte and cardiovascular responses in male and female. But are only the activational and organizational hormonal effects to blame for such differences? Males and females not only differ in their sex (males are born with testes and females with ovaries) but also carry different sex chromosome complements and are thus influenced throughout life by different genomes. In this review, we discuss our recent studies in order to evaluate whether sex chromosome complement is in part responsible for gender differences previously observed in ANG II bradycardic-baroreflex response and sodium depletion-induced sodium appetite and neural activity. To test the hypothesis that XX or XY contributes to the dimorphic ANG II bradycardic-baroreflex response, we used the four core genotype mouse model, in which the effects of gonadal sex (testes or ovaries) and sex chromosome complement (XX or XY) are dissociated. The results indicate that ANG II bradycardic-baroreflex sexual dimorphic response may be ascribed to differences in sex chromosomes, indicating an XX-sex chromosome complement facilitatory bradycardic-baroreflex control of heart rate. Furthermore, we evaluated whether genetic differences within the sex chromosome complement may differentially modulate the known sexually dimorphic sodium appetite as well as basal or induced brain activity due to physiological stimulation of the renin-angiotensin system by furosemide and low-sodium treatment. Our studies demonstrate an organizational hormonal effect on sexually dimorphic induced sodium intake in mice, while at the brain level (subfornical organ and area postrema) we showed a sex chromosome complement effect in sodium-depleted mice, suggesting a sex chromosome gene participation in the modulation of neural pathways underlying regulatory response to renin-angiotensin stimulation. PMID:26260434

  13. Depletion of Securin Induces Senescence After Irradiation and Enhances Radiosensitivity in Human Cancer Cells Regardless of Functional p53 Expression

    SciTech Connect

    Chen Wenshu; Yu Yichu; Lee Yijang; Chen, J.-H.; Hsu, H.-Y.; Chiu, S.-J.

    2010-06-01

    Purpose: Radiotherapy is one of the best choices for cancer treatment. However, various tumor cells exhibit resistance to irradiation-induced apoptosis. The development of new strategies to trigger cancer cell death besides apoptosis is necessary. This study investigated the role of securin in radiation-induced apoptosis and senescence in human cancer cells. Methods and Materials: Cell survival was determined using clonogenic assays. Western blot analysis was used to analyze levels of securin, caspase-3, PARP, p53, p21, Rb, gamma-H2AX, and phospho-Chk2. Senescent cells were analyzed using a beta-galactosidase staining assay. A securin-expressed vector (pcDNA-securin) was stably transfected into securin-null HCT116 cells. Securin gene knockdown was performed by small interfering RNA and small hairpin RNA in HCT116 and MDA-MB-231 cells, respectively. Results: Radiation was found to induce apoptosis in securin wild type HCT116 cells but induced senescence in securin-null cells. Restoration of securin reduced senescence and increased cell survival in securin-null HCT116 cells after irradiation. Radiation-induced gamma-H2AX and Chk2 phosphorylation were induced transiently in securin-wild-type cells but exhibited sustained activation in securin-null cells. Securin gene knockdown switches irradiation-induced apoptosis to senescence in both HCT116 p53-null and MDA-MB-231 cells. Conclusions: Our results demonstrated that the level of securin expression plays a determining role in the radiosensitivity and fate of cells. Depletion of securin impairs DNA repair after irradiation, increasing DNA damage and promoting senescence in the residual surviving cells regardless of functional p53 expression. The knockdown of securin may contribute to a novel radiotherapy protocol for the treatment of human cancer cells that are resistant to irradiation.

  14. Resistance to radiation-induced apoptosis in Bcl-2-expressing cells is reversed by depleting cellular thiols.

    PubMed

    Mirkovic, N; Voehringer, D W; Story, M D; McConkey, D J; McDonnell, T J; Meyn, R E

    1997-09-18

    The mechanism by which Bcl-2 oncogene expression inhibits radiation-induced apoptosis has been investigated in two mouse lymphoma cell lines: line LY-as is radiation sensitive, displays substantial radiaton-induced apoptosis, and expresses low levels of Bcl-2; line LY-ar is radiation-resistant, displays a low apoptosis propensity, and expresses 30-fold higher amount of Bcl-2 protein than does the sensitive line. We observed that upon incubation in cystine/methionine-free (C/M-) medium, radiation-induced apoptosis in the LY-ar cells was restored to levels comparable to that seen in the LY-as cells. lntracellular glutathione (GSH) concentrations in LY-ar cells incubated in C/M- medium plummeted to 50% of control values within 2 h. LY-ar cells treated with diethyl maleate (DEM) or diamide, agents that deplete cellular thiols, had increased susceptibility to radiation-induced apoptosis in a manner similar to C/M- medium. These results are consistent with the general idea that Bcl-2 expression blocks apoptosis through an antioxidant pathway that involves cellular thiols. That Bcl-2-expressing tumor cells can be sensitized by exogeneous agents that modify cellular thiols offers strategies for overcoming such resistance. PMID:9333022

  15. Response of epididymal duct to the temporary depletion of spermatozoa induced by testicular irradiation in mice

    SciTech Connect

    Abe, K.; Takano, H.; Ito, T.

    1983-09-01

    The mouse epididymal duct can be histologically divided into five segments (I-V), and the principal cells in segment II appear to secrete periodic acid-Schiff (PAS)-positive material into the lumen. In this study, male dd-mice received one, two, or four 800-R doses of radiation beginning at age 50 days. Mice receiving multiple doses were irradiated at 1-week intervals. After irradiation, marked depletion of spermatozoa, or aspermia, occurred in the epididymal duct for 2 to 16 weeks after a latency period of 3 to 4 weeks according to the times of irradiations. During oligospermia or aspermia, PAS-positive inclusions appeared in the principal cells in segment IV. The inclusions occupied a supranuclear position and appeared as round granules and globules measuring 2-15 micron in diameter, and increased in number, size, and staining intensity with time. They disappeared after reappearance of spermatozoa. The findings suggest that PAS-positive material may bind to spermatozoa and, if not bound, is reabsorbed by the principal cells in segment IV and deposited as intracellular inclusions, and the principal cells in segment IV are capable of digesting the accumulated PAS-positive material.

  16. Testosterone Depletion Induces Demethylation of Murine Reelin Promoter CpG Dinucleotides: A Preliminary Study

    PubMed Central

    da Silva, Victor Augusto Moraes; Dantas, Marília de Souza; Silva, Leonardo Agostinho de Castro; Carneiro, Juliana Garcia; Schamber-Reis, Bruno Luiz Fonseca

    2015-01-01

    Schizophrenia (SZ) is a debilitating mental disorder characterized by psychotic events, abnormal social behavior, false beliefs, and auditory hallucinations. Hypermethylation of the promoter region of reelin (RELN), a gene involved in regulation of neuronal positioning during telencephalic development, is strongly associated with low protein expression in several cortical structures and promoter hypermethylation in brain from postmortem SZ subjects. Recent experimental data suggests that testosterone is able to promote RELN demethylation, although no direct evidence of hormonal influence on reelin promoter methylation was obtained. We investigated if reduced levels of plasma testosterone in adult male mice lead to Reln promoter demethylation. Animals were administered with flutamide, an antiandrogenic compound, and reelin promoter methylation was assessed using methylationspecific PCR using bisulfite DNA from cerebellum. We found that flutamide was able to significantly lower plasma testosterone when compared to control mice, and treatment did not influence animal survival and body weight. We also show that low plasma testosterone was associated with demethylation of a cytosine residue located at −860 in reelin promoter region. These preliminary data suggest that androgenic hormones can influence cerebral reelin demethylation. To our knowledge, this is the first experimental approach directly linking testosterone depletion and RELN promoter methylation. PMID:26526966

  17. Low Nourishment of Vitamin C Induces Glutathione Depletion and Oxidative Stress in Healthy Young Adults.

    PubMed

    Waly, Mostafa I; Al-Attabi, Zahir; Guizani, Nejib

    2015-09-01

    The present study was conducted to assess the status of vitamin C among healthy young adults in relation to serum antioxidant parameters [glutathione (GSH), thiols, and total antioxidant capacity, (TAC)], and oxidative stress markers [malondialdehyde (MDA), and nitrites plus nitrates (NN)]. A prospective study included 200 young adults, and their dietary intake was assessed by using food diaries. Fasting plasma vitamin C, serum levels of GSH, thiols, TAC, MDA, and NN were measured using biochemical assays. It was observed that 38% of the enrolled subjects, n=76, had an adequate dietary intake of vitamin C (ADI group). Meanwhile, 62%, n=124, had a low dietary intake of vitamin C (LDI group) as compared to the recommended dietary allowances. The fasting plasma level of vitamin C was significantly higher in the ADI group as compared to the LDI group. Oxidative stress in the sera of the LDI group was evidenced by depletion of GSH, low thiols levels, impairment of TAC, an elevation of MDA, and increased NN. In the ADI group, positive correlations were found between plasma vitamin C and serum antioxidant parameters (GSH, thiols, and TAC). Meanwhile, the plasma vitamin C was negatively correlated with serum MDA and NN levels. This study reveals a significant increase of oxidative stress status and reduced antioxidant capacity in sera from healthy young adults with low intake of the dietary antioxidant, vitamin C. PMID:26451357

  18. Innate immune-induced depletion of bone marrow neutrophils aggravates systemic bacterial infections

    PubMed Central

    Navarini, Alexander A.; Lang, Karl S.; Verschoor, Admar; Recher, Mike; Zinkernagel, Annelies S.; Nizet, Victor; Odermatt, Bernhard; Hengartner, Hans; Zinkernagel, Rolf M.

    2009-01-01

    Neutrophils are the most abundant leukocytes in circulation and provide a primary innate immune defense function against bacterial pathogens before development of a specific immune response. These specialized phagocytes are short lived (1224 hours) and continuously replenished from bone marrow. We found that if the host is overwhelmed by a high inoculum of Listeria monocytogenes, neutrophils are depleted despite high granulocyte-colony stimulating factor induction. In contrast to a low-dose innocuous L. monocytogenes infection, high-dose Listeria challenge blocks neutrophil recruitment to infectious abscesses and bacterial proliferation is not controlled, resulting in lethal outcomes. Administering synthetic TLR2-ligand or heat-killed bacteria during the innocuous L. monocytogenes infection reproduced these effects, once again leading to overwhelming bacterial propagation. The same stimuli also severely aggravated Salmonella typhimurium, Staphylococcus aureus, and Streptococcus pyogenes systemic infection. These data implicate systemic innate immune stimulation as a mechanism of bone marrow neutrophil exhaustion which negatively influences the outcome of bacterial infections. PMID:19351895

  19. Low Nourishment of Vitamin C Induces Glutathione Depletion and Oxidative Stress in Healthy Young Adults

    PubMed Central

    Waly, Mostafa I.; Al-Attabi, Zahir; Guizani, Nejib

    2015-01-01

    The present study was conducted to assess the status of vitamin C among healthy young adults in relation to serum antioxidant parameters [glutathione (GSH), thiols, and total antioxidant capacity, (TAC)], and oxidative stress markers [malondialdehyde (MDA), and nitrites plus nitrates (NN)]. A prospective study included 200 young adults, and their dietary intake was assessed by using food diaries. Fasting plasma vitamin C, serum levels of GSH, thiols, TAC, MDA, and NN were measured using biochemical assays. It was observed that 38% of the enrolled subjects, n=76, had an adequate dietary intake of vitamin C (ADI group). Meanwhile, 62%, n=124, had a low dietary intake of vitamin C (LDI group) as compared to the recommended dietary allowances. The fasting plasma level of vitamin C was significantly higher in the ADI group as compared to the LDI group. Oxidative stress in the sera of the LDI group was evidenced by depletion of GSH, low thiols levels, impairment of TAC, an elevation of MDA, and increased NN. In the ADI group, positive correlations were found between plasma vitamin C and serum antioxidant parameters (GSH, thiols, and TAC). Meanwhile, the plasma vitamin C was negatively correlated with serum MDA and NN levels. This study reveals a significant increase of oxidative stress status and reduced antioxidant capacity in sera from healthy young adults with low intake of the dietary antioxidant, vitamin C. PMID:26451357

  20. Sensory CGRP depletion by capsaicin exacerbates hypoxia-induced pulmonary hypertension in rats.

    PubMed

    Tjen-A-Looi, S; Kraiczi, H; Ekman, R; Keith, I M

    1998-04-24

    Pulmonary hypertension is a debilitating disease that occurs among infants and adults. One of many etiologies is airway hypoxia. We previously demonstrated a role of endogenous calcitonin gene-related peptide (CGRP), a potent vasodilator, in ameliorating the pulmonary vascular pressor response to chronic hypoxia and related changes in the lungs and heart. This study evaluates the role of endogenous sensory CGRP in hypoxic pulmonary hypertension and examines the intrinsic neural microcircuitry. Rats were pretreated with capsaicin i.p. to deplete pulmonary sensory C-fiber stores of CGRP and substance P and placed in hypobaric hypoxia (10% O2, 16 days) or normoxia together with sham controls. Hypoxia increased pulmonary artery pressure, right-ventricular weight, arterial medial thickness, elasticized capillaries, endothelial cell density, lung water and hematocrit in control rats. Capsaicin augmented pulmonary artery pressure and right-ventricular hypertrophy in hypoxia, and medial thickness and endothelial cell density both in normoxia and hypoxia. Because of the limited effects on these parameters by substance P and other capsaicin-sensitive lung agents, our results suggest that sensory CGRP deficit severely exacerbates pathological signs of hypoxic pulmonary hypertension. A neural microcircuitry consistent with an axon reflex pathway is outlined histochemically. We conclude that endogenous CGRP modulates pulmonary vascular tone in hypoxic pulmonary hypertension which requires intact primary sensory fibers. PMID:9657352

  1. Acrylamide induces locomotor defects and degeneration of dopamine neurons in Caenorhabditis elegans.

    PubMed

    Li, Jia; Li, Dan; Yang, Yongsheng; Xu, Tiantian; Li, Ping; He, Defu

    2016-01-01

    Acrylamide can form in foods during the cooking process and cause multiple adverse effects. However, the neurotoxicity and mechanisms of acrylamide have not been fully elucidated. In Caenorhabditis elegans, we showed that 48 h exposure to 10-625 mg l(-1) acrylamide resulted in a significant decline in locomotor frequency of body bending, head thrashing and pharynx pumping. In addition, acrylamide exposure reduced crawling speeds and changed angles of body bending. It indicates that acrylamide induces locomotor defects, along with parkinsonian-like movement impairment, including bradykinesia and hypokinesia. Acrylamide also affected chemotaxis plasticity and reduced learning ability. Using transgenic nematodes, we found that acrylamide induced downexpression of Pdat-1 and led to the degeneration of dopaminergic neurons. Moreover, the enhanced expression of unc-54, encoding a subunit of ?-synuclein was found. It illustrates that acrylamide is efficient in inducing crucial parkinsonian pathology, including dopaminergic damage and ?-synuclein aggregation. These findings suggest the acrylamide-induced locomotor defects and neurotoxicity are associated with Parkinson's disease. Copyright 2015 John Wiley & Sons, Ltd. PMID:25876170

  2. Antenatal Glucocorticoid Treatment Induces Adaptations in Adult Midbrain Dopamine Neurons, which Underpin Sexually Dimorphic Behavioral Resilience

    PubMed Central

    Virdee, Kanwar; McArthur, Simon; Brischoux, Frdric; Caprioli, Daniele; Ungless, Mark A; Robbins, Trevor W; Dalley, Jeffrey W; Gillies, Glenda E

    2014-01-01

    We demonstrated previously that antenatal glucocorticoid treatment (AGT, gestational days 1619) altered the size and organization of the adult rat midbrain dopaminergic (DA) populations. Here we investigated the consequences of these AGT-induced cytoarchitectural disturbances on indices of DA function in adult rats. We show that in adulthood, enrichment of striatal DA fiber density paralleled AGT-induced increases in the numbers of midbrain DA neurons, which retained normal basal electrophysiological properties. This was co-incident with changes in (i) striatal D2-type receptor levels (increased, both sexes); (ii) D1-type receptor levels (males decreased; females increased); (iii) DA transporter levels (males increased; females decreased) in striatal regions; and (iv) amphetamine-induced mesolimbic DA release (males increased; females decreased). However, despite these profound, sexually dimorphic changes in markers of DA neurotransmission, in-utero glucocorticoid overexposure had a modest or no effect on a range of conditioned and unconditioned appetitive behaviors known to depend on mesolimbic DA activity. These findings provide empirical evidence for enduring AGT-induced adaptive mechanisms within the midbrain DA circuitry, which preserve some, but not all, functions, thereby casting further light on the vulnerability of these systems to environmental perturbations. Furthermore, they demonstrate these effects are achieved by different, often opponent, adaptive mechanisms in males and females, with translational implications for sex biases commonly found in midbrain DA-associated disorders. PMID:23929547

  3. The effects of experimentally induced bronchopneumonia on the pharmacokinetics and tissue depletion of gentamicin in healthy and pneumonic calves.

    PubMed

    Hunter, R P; Brown, S A; Rollins, J K; Nelligan, D F

    1991-09-01

    The effects of a bovine bronchopneumonia model on the pharmacokinetics and tissue residue depletion profiles of gentamicin in calves weighing 90-140 kg was explored. Two groups of heifer calves were used. The first was a normal group, while the second group had bronchopneumonia induced. A scoring system was developed to evaluate the extent of disease in the groups. A bimodal distribution of the serum pharmacokinetic parameters in the pneumonic group was caused by the effects of dehydration. When the severely dehydrated calves were omitted from the analysis, serum clearance of gentamicin was significantly higher in the pneumonic group than in the normal group (P less than 0.05). The pharmacokinetic equations used to fit the tissue concentrations varied from tissue to tissue and between groups. Because the best equation of a particular tissue's concentrations varied between groups, withdrawal periods, which are normally determined in healthy animals, may be inappropriate in diseased animals. Addition of several parameters (serum creatinine, serum urea nitrogen, albumin, fibrinogen, and total protein concentrations, white blood cell counts, central fluid volume, volume of distribution at steady state, area under the serum concentration vs time curve, serum clearance, and elimination rate constant) to these tissue-depletion models using multiple regression improved the prediction of a concentration in a given tissue. PMID:1744937

  4. Age- and location-dependent differences in store depletion-induced h-channel plasticity in hippocampal pyramidal neurons

    PubMed Central

    Clemens, Ann M.

    2013-01-01

    Disruptions of endoplasmic reticulum (ER) Ca2+ homeostasis are heavily linked to neuronal pathology. Depletion of ER Ca2+ stores can result in cellular dysfunction and potentially cell death, although adaptive processes exist to aid in survival. We examined the age and region dependence of one postulated, adaptive response to ER store-depletion (SD), hyperpolarization-activated cation-nonspecific (h)-channel plasticity in neurons of the dorsal and ventral hippocampus (DHC and VHC, respectively) from adolescent and adult rats. With the use of whole-cell patch-clamp recordings from the soma and dendrites of CA1 pyramidal neurons, we observed a change in h-sensitive measurements in response to SD, induced by treatment with cyclopiazonic acid, a sarcoplasmic reticulum/ER Ca2+-ATPase blocker. We found that whereas DHC and VHC neurons in adolescent animals respond to SD with a perisomatic expression of SD h plasticity, adult animals express SD h plasticity with a dendritic and somatodendritic locus of plasticity in DHC and VHC neurons, respectively. Furthermore, SD h plasticity in adults was dependent on membrane potential and on the activation of L-type voltage-gated Ca2+ channels. These results suggest that cellular responses to the impairment of ER function, or ER stress, are dependent on brain region and age and that the differential expression of SD h plasticity could provide a neural basis for region- and age-dependent disease vulnerabilities. PMID:24381027

  5. Clonal evolution following chemotherapy-induced stem cell depletion in cats heterozygous for glucose-6-phosphate dehydrogenase

    SciTech Connect

    Abkowitz, J.L.; Ott, R.M.; Holly, R.D.; Adamson, J.W.

    1988-06-01

    The number of hematopoietic stem cells necessary to support normal hematopoiesis is not known but may be small. If so, the depletion or damage of such cells could result in apparent clonal dominance. To test this hypothesis, dimethylbusulfan (2 to 4 mg/kg intravenously (IV) x 3) was given to cats heterozygous for the X-linked enzyme glucose-6-phosphate dehydrogenase (G-6-PD). These cats were the daughters of domestic X Geoffroy parents. After the initial drug-induced cytopenias (2 to 4 weeks), peripheral blood counts and the numbers of marrow progenitors detected in culture remained normal, although the percentages of erythroid burst-forming cells (BFU-E) and granulocyte/macrophage colony-forming cells (CFU-GM) in DNA synthesis increased, as determined by the tritiated thymidine suicide technique. In three of six cats treated, a dominance of Geoffroy-type G-6-PD emerged among the progenitor cells, granulocytes, and RBCs. These skewed ratios of domestic to Geoffroy-type G-6-PD have persisted greater than 3 years. No changes in cell cycle kinetics or G-6-PD phenotypes were noted in similar studies in six control cats. These data suggest that clonal evolution may reflect the depletion or damage of normal stem cells and not only the preferential growth and dominance of neoplastic cells.

  6. Targeting Dopamine in Acute Traumatic Brain Injury

    PubMed Central

    Bales, James W.; Kline, Anthony E.; Wagner, Amy K.; Dixon, C. Edward

    2010-01-01

    In addition to the initial mechanical damage, traumatic brain injury (TBI) induces a series of secondary insults, such as, but not limited to, excitotoxicity, metabolic disruption, and oxidative stress. Neuroprotective strategies after TBI have traditionally focused on cellular preservation as the measurable endpoint although multiple lines of evidence indicate that even with significant neuronal sparing deficits remain at both the cellular and behavioral level. As such, the development of therapies that can effectively confer both neuronal sparing and post-injury functional benefit is critical to providing the best treatment options for clinical TBI. Targeting dopaminergic signaling pathways is a novel approach in TBI that provides benefits to both neuronal survival and functional outcomes. Dopamine, like glutamate, can cause oxidative stress and significant cellular dysfunction when either depleted or over-expressed, and also plays an important role in central nervous system inflammation. The purpose of this review is to discuss dopamine in acute TBI and the role that dopaminergic therapies have as neuroprotective strategies. PMID:22308176

  7. Critical depletion.

    PubMed

    Buzzaccaro, Stefano; Colombo, Jader; Parola, Alberto; Piazza, Roberto

    2010-11-01

    Depletion interactions and the critical Casimir effect are usually regarded as distinct phenomena in colloidal suspensions. By experimentally investigating how the Asakura-Oosawa picture, appropriate for a weakly correlated depletant, is modified when critical correlations develop within the depletion agent, we conversely show that the former merges continuously into the latter, leading to a distinctive scaling behavior solely dictated by the depletant correlation length. A model based on density functional theory provides a microscopic understanding of the phenomenon and properly accounts for the observed trends. PMID:21231200

  8. Depletion of a microtubule-associated motor protein induces the loss of dendritic identity.

    PubMed

    Yu, W; Cook, C; Sauter, C; Kuriyama, R; Kaplan, P L; Baas, P W

    2000-08-01

    Dendrites are short stout tapering processes that are rich in ribosomes and Golgi elements, whereas axons are long thin processes of uniform diameter that are deficient in these organelles. It has been hypothesized that the unique morphological and compositional features of axons and dendrites result from their distinct patterns of microtubule polarity orientation. The microtubules within axons are uniformly oriented with their plus ends distal to the cell body, whereas microtubules within dendrites are nonuniformly oriented. The minus-end-distal microtubules are thought to arise via their specific transport into dendrites by the motor protein known as CHO1/MKLP1. According to this model, CHO1/MKLP1 transports microtubules with their minus ends leading into dendrites by generating forces against the plus-end-distal microtubules, thus creating drag on the plus-end-distal microtubules. Here we show that depletion of CHO1/MKLP1 from cultured neurons causes a rapid redistribution of microtubules within dendrites such that minus-end-distal microtubules are chased back to the cell body while plus-end-distal microtubules are redistributed forward. The dendrite grows significantly longer and thinner, loses its taper, and acquires a progressively more axon-like organelle composition. These results suggest that the forces generated by CHO1/MKLP1 are necessary for maintaining the minus-end-distal microtubules in the dendrite, for antagonizing the anterograde transport of the plus-end-distal microtubules, and for sustaining a pattern of microtubule organization necessary for the maintenance of dendritic morphology and composition. Thus, we would conclude that dendritic identity is dependent on forces generated by CHO1/MKLP1. PMID:10908619

  9. Acetic acid induces pH-independent cellular energy depletion in Salmonella enterica.

    PubMed

    Tan, Sin Mei; Lee, Sui Mae; Dykes, Gary A

    2015-03-01

    Weak organic acids are widely used as preservatives and disinfectants in the food industry. Despite their widespread use, the antimicrobial mode of action of organic acids is still not fully understood. This study investigated the effect of acetic acid on the cell membranes and cellular energy generation of four Salmonella strains. Using a nucleic acid/protein assay, it was established that acetic acid did not cause leakage of intracellular components from the strains. A scanning electron microscopy study further confirmed that membrane disruption was not the antimicrobial mode of action of acetic acid. Some elongated Salmonella cells observed in the micrographs indicated a possibility that acetic acid may inhibit DNA synthesis in the bacterial cells. Using an ATP assay, it was found that at a neutral pH, acetic acid caused cellular energy depletion with an ADP/ATP ratio in the range between 0.48 and 2.63 (p<0.05) that was apparent for the four Salmonella strains. We suggest that this effect was probably due solely to the action of undissociated acid molecules. The antimicrobial effect of acetic acid was better under acidic conditions (ADP/ATP ratio of 5.56 ± 1.27; p<0.05), where the role of both pH and undissociated acid molecules can act together. We concluded that the inhibitory effect of acetic acid is not solely attributable to acidic pH but also to undissociated acid molecules. This finding has implication for the use of acetic acid as an antimicrobial against Salmonella on food products, such as chicken meat, which can buffer its pH. PMID:25562466

  10. Topographical Assessment of Ethological and Dopamine Receptor Agonist-Induced Behavioral Phenotype in Mutants with Congenic DARPP-32 'Knockout'.

    PubMed

    Nally, Rachel E; McNamara, Fergal N; Clifford, Jeremiah J; Kinsella, A; Tighe, Orna; Croke, David T; Fienberg, Allen A; Greengard, Paul; Waddington, John L

    2003-12-01

    Congenic (10 backcrosses into C57BL/6J) mutants with targeted gene deletion of DARPP-32, a neuronal phosphoprotein regarded as an essential mediator of the biological effects of dopamine (DA), were assessed phenotypically using an ethologically based approach that resolves all topographies of behavior in the mouse repertoire. Over initial exploration, female, but not male, DARPP-32 mutants evidenced increased locomotion and decreased grooming, while a decrease in rearing seated was evident in mutants of both genders; continuing assessment over several hours did not reveal additional phenotypic effects. Following challenge with the nonselective DA receptor agonist apomorphine, low doses were associated with reduced levels of sniffing, grooming, total rearing, and rearing seated in DARPP-32 mutants relative to wildtypes; this would suggest some role for DARPP-32 in mediating the biological effects of presynaptic D(2)-like autoreceptor or inhibitory postsynaptic D(2)-like receptor activation. Following challenge with higher doses, while stereotyped sniffing and locomotion with chewing was largely unaltered, the additional murine response of Straub tail was essentially abolished in DARPP-32 mutants, indicating some specific involvement of DARPP-32 in mediating this topography of behavior; additionally, there were overall reductions in levels of sniffing, total rearing, rearing seated, and grooming in DARPP-32 mutants that were unrelated to the dose of apomorphine administered, indicating broader topographical effects following the stress of the injection procedure relative to more naturalistic conditions. The developmental absence of DARPP-32 following targeted gene deletion appears to be associated with compensatory processes that maintain certain topographies of spontaneous and agonist-induced DAergic function, while other topographies remain impaired. PMID:12865890

  11. Evidence for the involvement of dopamine in stress-induced suppression of reproduction in the cichlid fish Oreochromis mossambicus.

    PubMed

    Chabbi, A; Ganesh, C B

    2015-05-01

    In the present study, we examined whether stress-induced suppression of reproduction is mediated through the catecholaminergic neurotransmitter dopamine (DA) in the female cichlid fish Oreochromis mossambicus. In the first experiment, application of antibody against tyrosine hydroxylase (TH; a marker for DA) in brain sections revealed the presence of intensely stained TH immunoreactive cells in the preoptic area (POA) and nucleus preopticus (NPO) during the previtellogenic phase. These cells showed weak immunoreactivity during the vitellogenic and prespawning phases concomitant with darkly stained luteinising hormone (LH) immunoreactive content in the proximal pars distalis (PPD) of the pituitary gland and fully ripened follicles (stage V) in the ovary of control fish. However, in fish exposed to aquacultural stressors, TH secreting cells remained intensely stained in POA and NPO regions during the prespawning phase, indicating increased synthetic and secretory activity, which was reflected by a significantly higher DA content compared to controls. Increased DA activity as a result of stress was associated with a decrease in the LH immunoreactive content in the PPD and an absence of stage V follicles in the ovary. In the second experiment, administration of DA caused effects similar to those in stressed fish, whereas DA receptor antagonist domperidone (DOM) treatment significantly increased the LH content in the PPD and the number of stage V follicles in unstressed fish. On the other hand, treatment of stressed fish with DOM resulted in dark accumulations of LH immunoreactive content in the PPD accompanied by the presence of stage V follicles in the ovary. Taken together, these results suggest an additional pathway for the inhibitory effects of stress through dopaminergic neurones along the reproductive axis. PMID:25712855

  12. N-tert-butyl-alpha-phenylnitrone protects against 3,4-methylenedioxymethamphetamine-induced depletion of serotonin in rats.

    PubMed

    Yeh, S Y

    1999-03-01

    The present study examined the effect of N-tert-butyl-alpha-phenylnitrone (PBN) on 3,4-methylenedioxmathamphetamine (MDMA)-induced depletion of serotonin in the CNS. Rats were treated with two concurrent injections of MDMA (20 mg/kg, s.c.), PBN (50-400 mg/kg dissolved in ethanol, 50 mg/ml of 25% ethanol, i.p.), saline or 25% ethanol, alone or in combination, 6 h apart, and sacrificed 5 days later. Rectal temperature was measured prior to and hourly following the drug injection for 5 h. Monoamine levels in the tissue were measured by HPLC. Density of the 5-HT transporters was assayed by [3H]paroxetine binding. Rectal temperature of rats increased after MDMA, decreased after PBN, ethanol, PBN plus ethanol, and MDMA plus ethanol, and was not significantly altered after MDMA plus PBN. Levels of 5-HT and 5-HIAA in the frontal cortex, hippocampus, striatum, and brain stem of rats decreased significantly after MDMA or MDMA plus ethanol, but not after MDMA plus PBN, PBN plus ethanol (PBN dissolved in ethanol), or ethanol as compared to the saline controls. Levels of 5-HT and 5-HIAA in the brain tissues of rats treated with MDMA plus PBN were elevated as compared to those treated with MDMA plus saline. Similar results were observed in the density of 5-HT transporters in the frontal cortex and hippocampus. These results indicate that scavenging of free radicals of MDMA metabolites or reactive oxygen species by PBN and with lowering of body temperature protected against MDMA-induced depletion of serotonin transmitter. PMID:10029234

  13. Dopamine D1 receptor activation improves PCP-induced performance disruption in the 5C-CPT by reducing inappropriate responding.

    PubMed

    Barnes, S A; Young, J W; Bate, S T; Neill, J C

    2016-03-01

    Attentional deficits contribute significantly to the functional disability of schizophrenia patients. The 5-choice continuous performance test (5C-CPT) measures attention in mice, rats, and humans, requiring the discrimination of trial types that either require a response or the inhibition of a response. The 5C-CPT, one version of human continuous performance tests (CPT), enables attentional testing in rodents in a manner consistent with humans. Augmenting the prefrontal cortical dopaminergic system has been proposed as a therapeutic target to attenuate the cognitive disturbances associated with schizophrenia. Using translational behavioural tasks in conjunction with inducing conditions relevant to schizophrenia pathophysiology enable the assessment of pro-attentive properties of compounds that augment dopaminergic activity. Here, using a repeated phencyclidine (PCP) treatment regimen and the 5C-CPT paradigm, we assess the pro-attentive properties of SKF 38393, a dopamine D1 receptor agonist, in rats. We show that repeated PCP treatment induces robust deficits in 5C-CPT performance indicative of impaired attention. Pre-treatment with SKF 38393 partially attenuates the PCP-induced deficits in 5C-CPT performance by reducing false alarm responding and increasing response accuracy. Impaired target detection was still evident in SKF 38393-treated rats however. Thus, augmentation of the dopamine D1 system improves PCP-induces deficits in 5C-CPT performance by selectively reducing aspects of inappropriate responding. These findings provide evidence to support the hypothesis that novel therapies targeting the dopamine D1 receptor system could improve aspects of attentional deficits in schizophrenia patients. PMID:26658514

  14. gamma-Aminobutyric acidA agonists differentially augment gnawing induced by indirect-acting dopamine agonists in C57BL/6J mice.

    PubMed

    Tirelli, E; Geter-Douglass, B; Witkin, J M

    1998-01-01

    Evidence from structure-activity, molecular biology, ligand binding and behavioral studies has suggested potential differences in the pharmacological effects of indirect dopamine agonists. Striatal dopaminergic neurotransmission is under the regulatory control of GABAergic inputs. The ability of agonists of gamma-aminobutyric acidA (GABAA) receptors to enhance stereotyped gnawing was used as a method for dissociating the pharmacological effects of indirect-acting dopamine agonists. Gnawing on corrugated cardboard was studied in C57BL/6J mice. The GABAA agonists, gaboxadol HCl (THIP) and muscimol, were not effective in augmenting gnawing in the presence of the direct-acting dopamine agonists, apomorphine, pergolide, RU 24213 or SKF 38393. In addition, THIP did not enhance the gnawing produced by cocaine, bupropion, GBR 12909 or WIN 35428. In contrast, THIP produced marked augmentation of the gnawing induced by methylphenidate, (+)-amphetamine, methamphetamine, amfonelic acid, indatraline, nomifensine, diclofensine, mazindol and GBR 12935. The qualitative differences in potentiation were not caused by differences in the maximal effect of the drugs alone, inadequate dose or routes of administration, or by differences in duration of action. Neither can the absence of potentiation be accounted for by unique effects of THIP; muscimol was only marginally effective in potentiating the effects of WIN 35428 and bupropion but completely inactive in augmenting the effects of cocaine and GBR 12909. Muscimol was efficacious in augmenting the effects of the drugs for which THIP was active. These results add to a small but growing literature that demonstrates differences in the in vitro and in vivo pharmacological effects of indirect dopamine agonists. The methods used here may help in defining the molecular and neural substrates of these differential effects. PMID:9435169

  15. Mesolimbic Dopamine Transients in Motivated Behaviors: Focus on Maternal Behavior

    PubMed Central

    Robinson, Donita L.; Zitzman, Dawnya L.; Williams, Sarah K.

    2011-01-01

    Phasic activity of the mesolimbic dopamine pathway – burst-firing of dopamine neurons and the resulting dopamine release events at striatal targets – have been associated with a variety of motivational events, such as novelty, salient stimuli, social interaction, and reward prediction. Over the past decade, advances in electrochemical techniques have allowed measurement of naturally occurring dopamine release events, or dopamine transients, in awake animals during ongoing behavior. Thus, a growing body of studies has revealed dynamic dopamine input to ventral striatum during motivated behavior in a variety of experimental paradigms. We propose that dopamine transients may be important neural signals in pup-directed aspects of maternal behavior, as preliminary data suggest that dopamine transients in dams are associated with pup cues. Measurements of dopamine transients may be useful to investigate not only typical maternal behavior but also maternal inattention induced by drug exposure or stress. PMID:21629844

  16. Mesolimbic dopamine transients in motivated behaviors: focus on maternal behavior.

    PubMed

    Robinson, Donita L; Zitzman, Dawnya L; Williams, Sarah K

    2011-01-01

    Phasic activity of the mesolimbic dopamine pathway - burst-firing of dopamine neurons and the resulting dopamine release events at striatal targets - have been associated with a variety of motivational events, such as novelty, salient stimuli, social interaction, and reward prediction. Over the past decade, advances in electrochemical techniques have allowed measurement of naturally occurring dopamine release events, or dopamine transients, in awake animals during ongoing behavior. Thus, a growing body of studies has revealed dynamic dopamine input to ventral striatum during motivated behavior in a variety of experimental paradigms. We propose that dopamine transients may be important neural signals in pup-directed aspects of maternal behavior, as preliminary data suggest that dopamine transients in dams are associated with pup cues. Measurements of dopamine transients may be useful to investigate not only typical maternal behavior but also maternal inattention induced by drug exposure or stress. PMID:21629844

  17. Hemorrhage trauma increases radiation-induced trabecular bone loss and marrow cell depletion in mice.

    PubMed

    Swift, Joshua M; Smith, Joan T; Kiang, Juliann G

    2015-05-01

    Exposure to high-dose radiation results in deleterious effects on skeletal tissue. However, the effects of combined trauma such as radiation and hemorrhage on skeletal properties have yet to be elucidated. The purpose of this study was to evaluate the effects of radiation injury combined with hemorrhage on trabecular bone properties and biomarkers of bone metabolism, and to determine whether hemorrhage enhances radiation-associated bone loss. Male CD2F1 mice (10 weeks old) were exposed to one single dose of gamma radiation ((60)Co): 0 or 7.25 Gy. Two hours after irradiation, animals were bled 0% (n = 8) or 20% (n = 8) of total blood volume via the submandibular vein. Mice were euthanized 30 days after irradiation, and distal femora were analyzed using standard histomorphometry to determine changes in trabecular bone volume (BV/TV), thickness (Tb.Th), spacing (Tb.Sp), number (Tb.N) and marrow adipocyte density. Femurs from mice euthanized 1, 7 and 15 days post injury were flushed and total bone marrow cells were counted. Radiation exposure resulted in deleterious effects on distal femur BV/TV (-63%), Tb.Th (-34%), Tb.N (-45%), Tb.Sp (+125%) and adipocyte density (+286%) compared with the sham-irradiated mice (0 Gy; P < 0.05). Hemorrhage after irradiation resulted in greater deleterious effects on the distal femur with BV/TV (-13%), Tb.Th (-44%), Tb.N (-26%), Tb.Sp (+29%) and marrow adipocyte density (+33%) compared with radiation exposure only (P < 0.05). Analysis of the biomarkers of bone metabolism in serum from irradiated and hemorrhaged mice revealed significantly lower levels of osteocalcin (-60%) and procollagen type 1 amino-terminal propeptide (-36%; P1NP, biomarkers of bone formation activity), as well as elevations in sclerostin (+56%; SOST, an inhibitor of bone formation) compared with serum from irradiated only mice (P < 0.05). Additionally, the onset of bone marrow cell depletion in irradiated and hemorrhaged mice occurred earlier and to a greater extent compared to that in irradiated only mice. This study provides definitive, preliminary evidence that hemorrhage further exacerbates trabecular bone loss associated with nonlethal high-dose gamma radiation. PMID:25897554

  18. What's shaking?: Understanding creep and induced seismicity in depleting sandstone reservoirs

    NASA Astrophysics Data System (ADS)

    Hangx, Suzanne; Spiers, Christopher

    2015-04-01

    Subsurface exploitation of the Earth's natural resources, such as oil, gas and groundwater, removes the natural system from its chemical and physical equilibrium. With global energy and water demand increasing rapidly, while availability diminishes, densely populated areas are becoming increasingly targeted for exploitation. Indeed, the impact of our geo-resources needs on the environment has already become noticeable. Deep groundwater pumping has led to significant surface subsidence in urban areas such as Venice and Bangkok. Hydrocarbons production has also led to subsidence and seismicity in offshore (e.g. Ekofisk, Norway) and onshore hydrocarbon fields (e.g. Groningen, the Netherlands). Fluid extraction inevitably leads to (poro)elastic compaction of reservoirs, hence subsidence and occasional fault reactivation. However, such effects often exceed what is expected from purely elastic reservoir behaviour and may continue long after exploitation has ceased or show other time-lag effects in relation to changes in production rates. One of the main hypotheses advanced to explain this is time-dependent compaction, or 'creep deformation', of such reservoirs, driven by the reduction in pore fluid pressure compared with the vertical rock overburden pressure. The operative deformation mechanisms may include grain-scale brittle fracturing and thermally-activated mass transfer processes (e.g. pressure solution). Unfortunately, these mechanisms are poorly known and poorly quantified. As a first step to better describe creep in sedimentary granular aggregates, we have derived a universal, simple model for intergranular pressure solution (IPS) within an ordered pack of spherical grains. This universal model is able to predict the conditions under which each of the respective pressure solution serial processes, i.e. diffusion, precipitation or dissolution, is dominant. In essence, this creates a generic deformation mechanism map for IPS in any granular material. We have used our model to predict the amount and rate of compaction for depleting reservoirs, and compared our predictions to known subsidence rates for reservoirs around the world. This gives a first order-comparison to verify whether or not IPS is an important mechanism in controlling reservoir creep.

  19. ?3-Adrenoceptor Antagonist SR59230A Attenuates the Imbalance of Systemic and Myocardial Oxygen Transport Induced by Dopamine in Newborn Lambs

    PubMed Central

    Gill, Richdeep S.; Cheung, Po-Yin; Yu, Xiaoyang; Aklabi, Mohammed Al; Nagendran, Jeevan; Quinonez, Luis G.; Li, Ying Qian; Miller, John; Ross, David B.; Rebeyka, Ivan M.; Li, Jia

    2012-01-01

    Background In neonates, the increase in O2-delivery (DO2) by dopamine is offset by a greater increase in O2-consumption (VO2). This has been attributed to ?3-adrenergic receptors in neonatal brown fat tissue. ?3 receptors in the heart have negative inotropic properties. We evaluated the effects of SR59230A, a ?3-antagonist, on the balance of systemic and myocardial O2-transport in newborn lambs treated with dopamine. Methods Lambs (25 days old, n = 12) were anesthetized and mechanically ventilated. Heart rate (HR) and rectal temperature were monitored. VO2 was measured by respiratory mass spectrometry and cardiac output (CO) by a pulmonary artery transonic flowmeter. Arterial, jugular bulb venous and coronary sinus blood gases and lactate were measured to calculate DO2, O2 extraction ratio (ERO2), myocardial O2 and lactate extraction ratios (mERO2, mERlac). After baseline measurements, lambs were randomized to receive SR59230A at 5 mg/kg iv (SRG) or placebo. Both groups received incremental doses of a dopamine infusion (05101520 mcg/kg/min) every 15 min. Measurements were repeated at the end of each dose. Results After SR59230A infusion, CO and HR trended to decrease (P = 0.06), but no significant changes occurred in other parameters. Over the incremental doses of dopamine, temperature increased in both groups (P < 0.0001) but to a lesser degree in SRG (P = 0.004). CO and HR increased (P = 0.005 and 0.04) and similarly in both groups (P > 0.1). DO2 trended to a small increase (P = 0.08). VO2 increased in both groups (P < 0.0001) but to a lesser degree in SRG (P < 0.0001). As a result, ERO2 increased in both groups (P < 0.0001), but to a lesser degree in SRG (P < 0.0001). mERO2 was lower in SRG (P = 0.01) with a faster increase (P < 0.0001). mERlac was higher in SRG (P = 0.06) with a faster decrease (P = 0.04). Conclusion Although SR59230A tends to induce an initial drop in CO, it significantly attenuates the rise in VO2 and hence the imbalance of systemic and myocardial O2 transport induced by dopamine at higher doses. Studies are warranted to examine the effect of SR59230A in cases of cardiac dysfunction and increased VO2, observed after cardiac surgery. PMID:22442641

  20. Reduction by acetylsalicylic acid of paracetamol-induced hepatic glutathione depletion in rats treated with 4,4'-dichlorobiphenyl, phenobarbitone and pregnenolone-16-alpha-carbonitrile.

    PubMed

    van Bree, L; Groot, E J; De Vries, J

    1989-05-01

    The role of enzyme induction in the reduction by acetylsalicylic acid (ASA) of paracetamol-induced hepatic glutathione (GSH) depletion has been studied in rats. Administration of an overdose of paracetamol to control rats resulted in an appreciable decrease of GSH concentration. Pretreatment with the enzyme inducers phenobarbitone, 3-methylcholanthrene (3-MC), pregnenolone-16-alpha-carbonitrile (PCN) and 4,4'-dichlorobiphenyl (4,4'-DCB) significantly potentiated the paracetamol-induced depletion of GSH. Simultaneous administration of an equimolar dose of ASA resulted in a reduction of the paracetamol-induced depletion of GSH in all instances except for those rats that were not pretreated and those given 3-MC. Benorylate, the ASA ester of paracetamol, depressed rat liver GSH to levels comparable to those produced by the combination of paracetamol and ASA. ASA itself caused only minor changes in liver GSH concentrations. The results demonstrate that ASA causes a diminution of paracetamol-induced GSH depletion in rats with phenobarbitone type of enzyme induction. Inhibition of the formation of the reactive metabolite of paracetamol or reduction of the absorption rate of paracetamol seem to be unlikely as mechanisms underlying the ASA-induced effect. An ASA-mediated effect via changes of the hepatic thiol status is proposed. PMID:2569524

  1. Effect of Zishenpingchan Granule on Neurobehavioral Manifestations and the Activity and Gene Expression of Striatal Dopamine D1 and D2 Receptors of Rats with Levodopa-Induced Dyskinesias

    PubMed Central

    Ye, Qing; Yuan, Xiao-Lei; Zhou, Jie; Yuan, Can-xing; Yang, Xu-ming

    2014-01-01

    This study was performed to observe the effects of Zishenpingchan granule on neurobehavioral manifestations and the activity and gene expression of striatal dopamine D1 and D2 receptors of rats with levodopa-induced dyskinesias (LID). We established normal control group, LID model group, and TCM intervention group. Each group received treatment for 4 weeks. Artificial neural network (ANN) was applied to excavate the main factor influencing variation in neurobehavioral manifestations of rats with LID. The results showed that overactivation in direct pathway mediated by dopamine D1 receptor and overinhibition in indirect pathway mediated by dopamine D2 receptor may be the main mechanism of LID. TCM increased the efficacy time of LD to ameliorate LID symptoms effectively mainly by upregulating dopamine D2 receptor gene expression. PMID:25477990

  2. N-Octanoyl Dopamine Treatment of Endothelial Cells Induces the Unfolded Protein Response and Results in Hypometabolism and Tolerance to Hypothermia

    PubMed Central

    Stamellou, Eleni; Fontana, Johann; Wedel, Johannes; Ntasis, Emmanouil; Sticht, Carsten; Becker, Anja; Pallavi, Prama; Wolf, Kerstin; Krmer, Bernhard K.; Hafner, Mathias; van Son, Willem J.; Yard, Benito A.

    2014-01-01

    Aim N-acyl dopamines (NADD) are gaining attention in the field of inflammatory and neurological disorders. Due to their hydrophobicity, NADD may have access to the endoplasmic reticulum (ER). We therefore investigated if NADD induce the unfolded protein response (UPR) and if this in turn influences cell behaviour. Methods Genome wide gene expression profiling, confirmatory qPCR and reporter assays were employed on human umbilical vein endothelial cells (HUVEC) to validate induction of UPR target genes and UPR sensor activation by N-octanoyl dopamine (NOD). Intracellular ATP, apoptosis and induction of thermotolerance were used as functional parameters to assess adaptation of HUVEC. Results NOD, but not dopamine dose dependently induces the UPR. This was also found for other synthetic NADD. Induction of the UPR was dependent on the redox activity of NADD and was not caused by selective activation of a particular UPR sensor. UPR induction did not result in cell apoptosis, yet NOD strongly impaired cell proliferation by attenuation of cells in the S-G2/M phase. Long-term treatment of HUVEC with low NOD concentration showed decreased intracellular ATP concentration paralleled with activation of AMPK. These cells were significantly more resistant to cold inflicted injury. Conclusions We provide for the first time evidence that NADD induce the UPR in vitro. It remains to be assessed if UPR induction is causally associated with hypometabolism and thermotolerance. Further pharmacokinetic studies are warranted to address if the NADD concentrations used in vitro can be obtained in vivo and if this in turn shows therapeutic efficacy. PMID:24926788

  3. The epigenetically active small chemical N-methyl pyrrolidone (NMP) prevents estrogen depletion induced osteoporosis.

    PubMed

    Gjoksi, Bebeka; Ghayor, Chafik; Siegenthaler, Barbara; Ruangsawasdi, Nisarat; Zenobi-Wong, Marcy; Weber, Franz E

    2015-09-01

    Currently, there are several treatments for osteoporosis however; they all display some sort of limitation and/or side effects making the need for new treatments imperative. We have previously demonstrated that NMP is a bioactive drug which enhances bone regeneration in vivo and acts as an enhancer of bone morphogenetic protein (BMP) in vitro. NMP also inhibits osteoclast differentiation and attenuates bone resorption. In the present study, we tested NMP as a bromodomain inhibitor and for osteoporosis prevention on ovariectomized (OVX) induced rats while treated systemically with NMP. Female Sprague-Dawley rats were ovariectomized and weekly NMP treatment was administrated 1 week after surgery for 15 weeks. Bone parameters and related serum biomarkers were analyzed. 15 weeks of NMP treatment decreased ovariectomy-induced gained weight in average by 43% and improved bone mineral density (BMD) and bone volume over total volume (BV/TV) in rat femur on average by 25% and 41% respectively. Moreover, mineral apposition rate and bone biomarkers of bone turnover in the treatment group were at similar levels with those of the Sham group. Due to the function of NMP as a low affinity bromodomain inhibitor and its mechanism of action involving osteoblasts/osteoclasts balance and inhibitory effect on inflammatory cytokines, NMP is a promising therapeutic compound for the prevention of osteoporosis. PMID:25959414

  4. Acute hypoxia-induced depletion of striatal nitric oxide synthase pathway.

    PubMed

    Molina, Francisco; Rus, Alma; Pedrosa, Juan ngel; del Moral, Mara Luisa

    2013-01-01

    Hypoxia-induced alteration of nitric oxide (NO) production may lead to brain disease, especially in the areas most sensitive to oxygen deficiency, such as the striatum. To date, the behaviour of the striatal NO pathway under hypoxia/reoxygenation remains unknown and its elucidation constitutes the aim of this work. Wistar rats were submitted to hypoxia (20min) and analyzed after 0h, 24h, and 5 days of reoxygenation. Expression, activity, and location of the NO synthase (NOS) isoforms (neuronal, endothelial, and inducible) as well as nitrated protein expression were analyzed in the rat striatum. NO levels were indirectly quantified as nitrates and nitrites (NO(x)), which act as NO-generating molecules. NOS isoform mRNA levels remained unaltered in hypoxic groups vs. normoxic control. However, quantification of immunoreaction showed a significant decrease in eNOS and nNOS after hypoxia. While in situ NOS activity and NO(x) levels fell, levels of nitrotyrosine-modified proteins rose throughout the reoxygenation period. Our data revealed the great complexity of the NO pathway, showing that both acute hypoxia and the successive recovery period down-regulated the NOS system in the rat striatum. However, under hypoxia/reoxygenation NO may be produced in a NOS-independent way from the NO-storage molecules, compensating for the hypoxia-reduced NOS activity. PMID:23261869

  5. Hydrogen sulfide preconditioning or neutrophil depletion attenuates ischemia-reperfusion-induced mitochondrial dysfunction in rat small intestine.

    PubMed

    Liu, Yajun; Kalogeris, Theodore; Wang, Meifang; Zuidema, Mozow Yusof; Wang, Qun; Dai, Hongyan; Davis, Michael J; Hill, Michael A; Korthuis, Ronald J

    2012-01-01

    The objectives of this study were to determine whether neutrophil depletion with anti-neutrophil serum (ANS) or preconditioning with the hydrogen sulfide (H(2)S) donor NaHS (NaHS-PC) 24 h prior to ischemia-reperfusion (I/R) would prevent postischemic mitochondrial dysfunction in rat intestinal mucosa and, if so, whether calcium-activated, large conductance potassium (BK(Ca)) channels were involved in this protective effect. I/R was induced by 45-min occlusion of the superior mesenteric artery followed by 60-min reperfusion in rats preconditioned with NaHS (NaHS-PC) or a BK(Ca) channel activator (NS-1619-PC) 24 h earlier or treated with ANS. Mitochondrial function was assessed by measuring mitochondrial membrane potential, mitochondrial dehydrogenase function, and cytochrome c release. Mucosal myeloperoxidase (MPO) and TNF-? levels were also determined, as measures of postischemic inflammation. BK(Ca) expression in intestinal mucosa was detected by immunohistochemistry and Western blotting. I/R induced mitochondrial dysfunction and increased tissue MPO and TNF-? levels. Although mitochondrial dysfunction was attenuated by NaHS-PC or NS-1619-PC, the postischemic increases in mucosal MPO and TNF-? levels were not. The protective effect of NaHS-PC or NS-1619-PC on postischemic mitochondrial function was abolished by coincident treatment with BK(Ca) channel inhibitors. ANS prevented the I/R-induced increase in tissue MPO levels and reversed mitochondrial dysfunction. These data indicate that neutrophils play an essential role in I/R-induced mucosal mitochondrial dysfunction. In addition, NaHS-PC prevents postischemic mitochondrial dysfunction (but not inflammation) by a BK(Ca) channel-dependent mechanism. PMID:21921289

  6. L-Arginine depletion blunts anti-tumor T cell responses by inducing myeloid-derived suppressor cells

    PubMed Central

    Fletcher, Matthew; Ramirez, Maria E.; Sierra, Rosa A.; Raber, Patrick; Thevenot, Paul; Al-Khami, Amir A.; Sanchez-Pino, Dulfary; Hernandez, Claudia; Wyczechowska, Dorota D.; Ochoa, Augusto C.; Rodriguez, Paulo C.

    2014-01-01

    Enzymatic depletion of the non-essential amino acid L-Arginine (L-Arg) in cancer patients by the administration of a pegylated form of the catabolic enzyme arginase I (peg-Arg I) has shown some promise as a therapeutic approach. However, L-Arg deprivation also suppresses T-cell responses in tumors. In this study, we sought to reconcile these observations by conducting a detailed analysis of the effects of peg-Arg I on normal T-cells. Strikingly, we found that peg-Arg I blocked proliferation and cell cycle progression in normal activated T-cells without triggering apoptosis or blunting T-cell activation. These effects were associated with an inhibition of aerobic glycolysis in activated T-cells, but not with significant alterations in mitochondrial oxidative respiration, which thereby regulated survival of T-cells exposed to peg-Arg I. Further mechanistic investigations showed that addition of citrulline, a metabolic precursor for L-Arg, rescued the anti-proliferative effects of peg-Arg I on T-cells in vitro. Moreover, serum levels of citrulline increased after in vivo administration of peg-Arg I. In support of the hypothesis that peg-Arg I acted indirectly to block T-cell responses in vivo, peg-Arg I inhibited T-cell proliferation in mice by inducing accumulation of myeloid-derived suppressor cells (MDSC). MDSC induction by peg-Arg I occurred through the general control non-repressed-2 eIF2? kinase. Moreover, we found that peg-Arg I enhanced the growth of tumors in mice in a manner that correlated with higher MDSC numbers. Taken together, our results highlight the risks of the L-Arg-depleting therapy for cancer treatment and suggest a need for co-targeting MDSC in such therapeutic settings. PMID:25406192

  7. Depletion of the transcriptional coactivators megakaryoblastic leukaemia 1 and 2 abolishes hepatocellular carcinoma xenograft growth by inducing oncogene-induced senescence

    PubMed Central

    Hampl, Veronika; Martin, Claudia; Aigner, Achim; Hoebel, Sabrina; Singer, Stephan; Frank, Natalie; Sarikas, Antonio; Ebert, Oliver; Prywes, Ron; Gudermann, Thomas; Muehlich, Susanne

    2013-01-01

    Megakaryoblastic leukaemia 1 and 2 (MKL1/2) are coactivators of the transcription factor serum response factor (SRF). Here, we provide evidence that depletion of MKL1 and 2 abolishes hepatocellular carcinoma (HCC) xenograft growth. Loss of the tumour suppressor deleted in liver cancer 1 (DLC1) and the subsequent activation of RhoA were prerequisites for MKL1/2 knockdown-mediated growth arrest. We identified oncogene-induced senescence as the molecular mechanism underlying the anti-proliferative effect of MKL1/2 knockdown. MKL1/2 depletion resulted in Ras activation, elevated p16 expression and hypophosphorylation of the retinoblastoma (Rb) protein in DLC1-deficient HCC cells. Interestingly, reconstitution of HuH7 HCC cells with DLC1 also induced senescence. Evaluation of the therapeutic efficacy of MKL1/2 knockdown in vivo revealed that systemic treatment of nude mice bearing HuH7 tumour xenografts with MKL1/2 siRNAs complexed with polyethylenimine (PEI) completely abolished tumour growth. The regression of the xenografts was associated with senescence. Importantly, PEI-complexed MKL1 siRNA alone was sufficient for complete abrogation of HCC xenograft growth. Thus, MKL1/2 represent promising novel therapeutic targets for the treatment of HCCs characterized by DLC1 loss. PMID:23853104

  8. Glutathione Depletion Accelerates Cigarette Smoke-Induced Inflammation and Airspace Enlargement.

    PubMed

    Gould, Neal S; Min, Elysia; Huang, Jie; Chu, Hong Wei; Good, Jim; Martin, Richard J; Day, Brian J

    2015-10-01

    The study objective was to assess age-related changes in glutathione (GSH) adaptive response to cigarette smoke (CS) exposure. Older cigarette smokers show a decline (67%) in lung epithelial lining fluid (ELF) GSH and a 1.8-fold decreased GSH adaptive response to cigarette smoking with a concomitant elevation (47%) of exhaled nitric oxide compared with younger smokers. In order to isolate the changes in tissue GSH from other age-related effects, pharmacological inhibition of the rate limiting step in GSH synthesis was employed to examine the lung's response to CS exposure in young mice. The ?-glutamylcysteine ligase inhibitor L-buthionine-sulfoximine (BSO) was administered in the drinking water (20 mM) to decrease by half the in vivo GSH levels to those found in aged mice and humans. Mice were then exposed to CS (3 h/day) for 5 or 15 days. Biochemical analysis of the ELF and lung tissue revealed an inhibition of the CS-induced GSH adaptive response by BSO with a concurrent increase in mixed protein-GSH disulfides indicating increased cysteine oxidation. The prevention of the GSH adaptive response led to an increase in pro-inflammatory cytokines present in the lung. Airspace enlargement is a hallmark of lung emphysema and was observed in mice treated with BSO and exposed to CS for as little as 15 days, whereas these types of changes normally take up to 6 months in this model. BSO treatment potentiated both lung elastase and matrix metalloproteinase activity in the CS group. These data suggest that age-related decline in the GSH adaptive response can markedly accelerate many of the factors thought to drive CS-induced emphysema. PMID:26149495

  9. Serotonin Depletion-Induced Maladaptive Aggression Requires the Presence of Androgens

    PubMed Central

    Studer, Erik; Nslund, Jakob; Andersson, Erik; Nilsson, Staffan; Westberg, Lars; Eriksson, Elias

    2015-01-01

    The sex hormone testosterone and the neurotransmitter serotonin exert opposite effects on several aspects of behavior including territorial aggression. It is however not settled if testosterone exerts its pro-aggressive effects by reducing serotonin transmission and/or if the anti-aggressive effect of serotonin requires the presence of the androgen. Using the resident intruder test, we now show that administration of the serotonin synthesis inhibitor para-chlorophenylalanine (300 mg/kg x 3 days) increases the total time of attack as well as the percentage amount of social behavior spent on attack but not that spent on threat i.e. that it induces a pattern of unrestricted, maladaptive aggression in gonadectomized C57Bl/6 male mice receiving testosterone replacement; in contrast, it failed to reinstate aggression in those not given testosterone. Whereas these results suggest the pro-aggressive effect of testosterone to be independent of serotonin, and not caused by an inhibition of serotonergic activity, the pCPA-induced induction of maladaptive aggression appears to require the presence of the hormone. In line with these findings, pCPA enhanced the total time of attack as well the relative time spent on attacks but not threats also in wild-type gonadally intact male C57Bl/6 mice, but failed to reinstate aggression in mice rendered hypo-aggressive by early knock-out of androgen receptors in the brain (ARNesDel mice). We conclude that androgenic deficiency does not dampen aggression by unleashing an anti-aggressive serotonergic influence; instead serotonin seems to modulate aggressive behavior by exerting a parallel-coupled inhibitory role on androgen-driven aggression, which is irrelevant in the absence of the hormone, and the arresting of which leads to enhanced maladaptive aggression. PMID:25978464

  10. 600 ns pulse electric field-induced phosphatidylinositol4,5-bisphosphate depletion.

    PubMed

    Tolstykh, Gleb P; Beier, Hope T; Roth, Caleb C; Thompson, Gary L; Ibey, Bennett L

    2014-12-01

    The interaction between nsPEF-induced Ca(2+) release and nsPEF-induced phosphatidylinositol4,5-bisphosphate (PIP2) hydrolysis is not well understood. To better understand this interrelation we monitored intracellular calcium changes, in cells loaded with Calcium Green-1 AM, and generation of PIP2 hydrolysis byproducts (inositol-1,4,5-trisphosphate (IP3) and diacylglycerol (DAG)) in cells transfected with one of two fluorescent reporter genes: PLC?-PH-EGFP or GFP-C1-PKC?-C1a. The percentage fluorescence differences (?F %) after exposures were determined. Upon nsPEF impact, we found that in the absence of extracellular Ca(2+) the population of IP3 liberated during nsPEF exposure (?F 6%3, n=22), is diminished compared to the response in the presence of calcium (?F 84%15, n=20). The production of DAG in the absence of extracellular Ca(2+) (?F 29%5, n=25), as well as in cells exposed to thapsigargin (?F 40%12, n=15), was not statistically different from cells exposed in the presence of extracellular calcium (?F 226%, n=18). This finding suggests that the change in intracellular calcium concentration is not solely driving the observed response. Interestingly, the DAG produced in the absence of Ca(2+) is the strongest near the membrane regions facing the electrodes, whereas the presence of extracellular Ca(2+) leads to a whole cell response. The reported observations of Ca(2+) dynamics combined with IP3 and DAG production suggest that nsPEF may cause a direct effect on the phospholipids within the plasma membrane. PMID:24530104

  11. Antigen receptor-mediated depletion of FOXP3 in induced regulatory T-lymphocytes via PTPN2 and FOXO1

    PubMed Central

    Bothur, Evita; Raifer, Hartmann; Haftmann, Claudia; Stittrich, Anna-Barbara; Brstle, Anne; Brenner, Dirk; Bollig, Nadine; Bieringer, Maria; Kang, Chol-Ho; Reinhard, Katharina; Camara, Brbel; Huber, Magdalena; Visekruna, Alexander; Steinhoff, Ulrich; Repenning, Antje; Bauer, Uta-Maria; Sexl, Veronika; Radbruch, Andreas; Sparwasser, Tim; Mashreghi, Mir-Farzin; Wah Mak, Tak; Lohoff, Michael

    2015-01-01

    Regulatory T-cells induced via IL-2 and TGF? in vitro (iTreg) suppress immune cells and are potential therapeutics during autoimmunity. However, several reports described their re-differentiation into pathogenic cells in vivo and loss of their key functional transcription factor (TF) FOXP3 after T-cell antigen receptor (TCR)-signalling in vitro. Here, we show that TCR-activation antagonizes two necessary TFs for foxp3 gene transcription, which are themselves regulated by phosphorylation. Although the tyrosine phosphatase PTPN2 is induced to restrain IL-2-mediated phosphorylation of the TF STAT5, expression of the TF FOXO1 is downregulated and miR-182, a suppressor of FOXO1 expression, is upregulated. TGF? counteracts the FOXP3-depleting TCR-signal by reassuring FOXO1 expression and by re-licensing STAT5 phosphorylation. Overexpressed phosphorylation-independent active versions of FOXO1 and STAT5 or knockdown of PTPN2 restores FOXP3 expression despite TCR-signal and absence of TGF?. This study suggests novel targets for stabilisation and less dangerous application of iTreg during devastating inflammation. PMID:26815406

  12. PML induces compaction, TRF2 depletion and DNA damage signaling at telomeres and promotes their alternative lengthening.

    PubMed

    Osterwald, Sarah; Deeg, Katharina I; Chung, Inn; Parisotto, Daniel; Wörz, Stefan; Rohr, Karl; Erfle, Holger; Rippe, Karsten

    2015-05-15

    The alternative lengthening of telomeres (ALT) mechanism allows cancer cells to escape senescence and apoptosis in the absence of active telomerase. A characteristic feature of this pathway is the assembly of ALT-associated promyelocytic leukemia (PML) nuclear bodies (APBs) at telomeres. Here, we dissected the role of APBs in a human ALT cell line by performing an RNA interference screen using an automated 3D fluorescence microscopy platform and advanced 3D image analysis. We identified 29 proteins that affected APB formation, which included proteins involved in telomere and chromatin organization, protein sumoylation and DNA repair. By integrating and extending these findings, we found that APB formation induced clustering of telomere repeats, telomere compaction and concomitant depletion of the shelterin protein TRF2 (also known as TERF2). These APB-dependent changes correlated with the induction of a DNA damage response at telomeres in APBs as evident by a strong enrichment of the phosphorylated form of the ataxia telangiectasia mutated (ATM) kinase. Accordingly, we propose that APBs promote telomere maintenance by inducing a DNA damage response in ALT-positive tumor cells through changing the telomeric chromatin state to trigger ATM phosphorylation. PMID:25908860

  13. Antigen receptor-mediated depletion of FOXP3 in induced regulatory T-lymphocytes via PTPN2 and FOXO1.

    PubMed

    Bothur, Evita; Raifer, Hartmann; Haftmann, Claudia; Stittrich, Anna-Barbara; Brüstle, Anne; Brenner, Dirk; Bollig, Nadine; Bieringer, Maria; Kang, Chol-Ho; Reinhard, Katharina; Camara, Bärbel; Huber, Magdalena; Visekruna, Alexander; Steinhoff, Ulrich; Repenning, Antje; Bauer, Uta-Maria; Sexl, Veronika; Radbruch, Andreas; Sparwasser, Tim; Mashreghi, Mir-Farzin; Wah Mak, Tak; Lohoff, Michael

    2016-01-01

    Regulatory T-cells induced via IL-2 and TGFβ in vitro (iTreg) suppress immune cells and are potential therapeutics during autoimmunity. However, several reports described their re-differentiation into pathogenic cells in vivo and loss of their key functional transcription factor (TF) FOXP3 after T-cell antigen receptor (TCR)-signalling in vitro. Here, we show that TCR-activation antagonizes two necessary TFs for foxp3 gene transcription, which are themselves regulated by phosphorylation. Although the tyrosine phosphatase PTPN2 is induced to restrain IL-2-mediated phosphorylation of the TF STAT5, expression of the TF FOXO1 is downregulated and miR-182, a suppressor of FOXO1 expression, is upregulated. TGFβ counteracts the FOXP3-depleting TCR-signal by reassuring FOXO1 expression and by re-licensing STAT5 phosphorylation. Overexpressed phosphorylation-independent active versions of FOXO1 and STAT5 or knockdown of PTPN2 restores FOXP3 expression despite TCR-signal and absence of TGFβ. This study suggests novel targets for stabilisation and less dangerous application of iTreg during devastating inflammation. PMID:26815406

  14. L-Stepholidine, a naturally occurring dopamine D1 receptor agonist and D2 receptor antagonist, attenuates heroin self-administration and cue-induced reinstatement in rats.

    PubMed

    Yue, Kai; Ma, Baomiao; Chen, Lin; Tian, Xiang; Ru, Qin; Gan, Yongping; Wang, Daisong; Jin, Guozhang; Li, Chaoying

    2014-01-01

    Opiate addiction is a chronic, relapsing brain disease characterized by persistent and uncontrolled drug-seeking behavior despite negative effects. L-Stepholidine (L-SPD) is an alkaloid extract of the Chinese herb Stephania intermedia with dopamine D1 receptor partial agonistic and D2 receptor antagonistic dual actions. The unique pharmacological profile of L-SPD suggests that L-SPD may be effective for the treatment of opiate addiction. The aim of this study was to characterize the effects of L-SPD on heroin self-administration on a fixed-ratio 1 schedule and cue-induced reinstatement under an extinction/reinstatement protocol. The effect of L-SPD on the locomotor activity of heroin-free rats was also tested. We found that 2.5, 5, and 10 mg/kg of L-SPD attenuated heroin self-administration and cue-induced reinstatement without affecting locomotor activity. These results showed that L-SPD, which has dual actions on dopamine D1 and D2 receptors, attenuates heroin self-administration and cue-induced reinstatement. PMID:24145772

  15. Modulation of Delta(9)-THC-induced increase of cortical and hippocampal acetylcholine release by micro opioid and D(1) dopamine receptors.

    PubMed

    Pisanu, A; Acquas, E; Fenu, S; Di Chiara, G

    2006-05-01

    The administration of Delta(9)-tetrahydrocannabinol (Delta(9)-THC) and synthetic cannabinoids stimulates acetylcholine (ACh) release in the rat prefrontal cortex (PFCx) and hippocampus as estimated by brain microdialysis. The present study was aimed at assessing whether the ability of Delta(9)-THC to stimulate ACh release is dependent upon opioid and dopamine (DA) receptors. Administration of the micro opioid receptor antagonists naloxone and naltrexone prevented the Delta(9)-THC-induced release of ACh in the PFCx and hippocampus. Similarly, bilateral infusion in the ventral tegmental area (VTA), 24h before Delta(9)-THC, of the pseudo-irreversible micro(1) antagonist naloxonazine completely prevented the increase of ACh release by Delta(9)-THC. Pre-treatment with the D(1) receptor antagonist SCH 39,166 reduced Delta(9)-THC-induced ACh release both in the PFCx and in the hippocampus. Since Delta(9)-THC has been shown to increase DA release in the nucleus accumbens (NAc) shell via a micro(1)-opioid receptor mediated mechanism located in the VTA (Tanda, G., Pontieri, F.E., Di Chiara, G., 1997. Cannabinoid and heroin activation of mesolimbic dopamine transmission by a common micro(1) opioid receptor mechanism. Science 276, 2048-2050.), we hypothesize that Delta(9)-THC-induced stimulation of ACh release in the PFCx and hippocampus is related to stimulation of endogenous opioids release in the VTA with secondary activation of DA neurons projecting to the NAc shell. PMID:16427098

  16. Exercise-induced rescue of tongue function without striatal dopamine sparing in a rat neurotoxin model of Parkinson disease

    PubMed Central

    Schaser, Allison J; Russell, John A

    2013-01-01

    Unilateral lesions to the medial forebrain bundle with 6-hydroxydopamine (6- OHDA) lead to force and timing deficits during a complex licking task. We hypothesized that training targeting tongue force generation during licking would improve timing and force measures and also lead to striatal dopamine sparing. Nine month-old male Fisher344/Brown Norway rats were used in this experiment. Sixteen rats were in the control condition and received tongue exercise (n=8) or no exercise (n=8). Fourteen rats were in the 6-OHDA lesion condition and underwent tongue exercise (n=7) and or no exercise (n=7). Following 4 weeks of training and post-training measures, all animals underwent bilateral stimulation of the hypoglossal nerves to measure muscle contractile properties and were then transcardially perfused and brain tissues collected for immunohistochemistry to examine striatal dopamine content. Results demonstrated that exercise animals performed better for maximal force, average force, and press rate than their no-exercise counterparts, and the 6-OHDA animals that underwent exercise performed as well as the control no exercise group. Interestingly, there were no group differences for tetanic muscle force, despite behavioral recovery of forces. Additionally, behavioral and neurochemical analyses indicate that there were no differences in striatal dopamine. Thus, targeted exercise can improve tongue force and timing deficits related to 6-OHDA lesions and this exercise likely has a central, versus peripheral (muscle strength) mechanism. However, this mechanism is not related to sparing of striatal dopamine content. PMID:23756136

  17. Single preexposure to fluphenazine produces persisting behavioral sensitization accompanied by tolerance to fluphenazine-induced striatal dopamine overflow in rats.

    PubMed

    Meil, W; See, R E

    1994-07-01

    Single, previous exposure to a neuroleptic has been shown to produce long-lasting changes in various measures of behavior and neurochemistry upon subsequent drug exposure. The present study examined the effects of a single preexposure to fluphenazine (0.3 or 1.0 mg/kg) or vehicle on the effects of subsequent fluphenazine administration 15 or 30 days later. Intracranial microdialysis was used to assess changes in striatal extracellular dopamine concentrations. Animals were tested for catalepsy response on a horizontal bar test while concurrently collecting dialysis samples. Previous fluphenazine exposure produced a profound tolerance to the effects of subsequent fluphenazine at day 15 or day 30 on increasing extracellular dopamine levels. In addition, animals that had received fluphenazine on the first trial showed significant sensitization to the cataleptic effects of fluphenazine at both time points. Pretreatment with vehicle did not result in tolerance to dopamine overflow and there was only minimal evidence of cataleptic sensitization to a subsequent fluphenazine challenge. Although the tolerance to dopamine overflow may only indirectly relate to behavioral sensitization, these results support the hypothesis that significant behavioral and neurochemical alterations persist for prolonged time periods following single neuroleptic exposure. PMID:7938113

  18. The role of the dopamine D2 receptor in descending control of pain induced by motor cortex stimulation in the neuropathic rat.

    PubMed

    Viisanen, Hanna; Ansah, Osei Bonsu; Pertovaara, Antti

    2012-11-01

    We studied in rats with a spinal nerve ligation-induced neuropathy whether dopamine D2 receptors (D2Rs) play a role in descending control of pain induced by stimulation of the primary motor cortex (M1). Noxious heat-evoked responses were determined in spinal dorsal horn wide-dynamic range (WDR) and nociceptive-specific (NS) neurons, with and without electrical M1 stimulation. A D2R antagonist, raclopride, was administered into the dorsal striatum or spinally in attempts to reverse spinal antinociception induced by M1 stimulation. Moreover, influence of M1 stimulation on the noxious heat-induced limb withdrawal reflex was determined following block of spinal D2Rs with raclopride or a lidocaine-induced block of the hypothalamic A11 cell group, the main source of spinal dopamine. Striatal administration of raclopride enhanced the heat-evoked baseline responses of WDR but not NS neurons and reversed the M1 stimulation-induced suppression of the heat response in WDR neurons. Following spinal administration of raclopride, M1 stimulation failed to suppress the heat response of WDR neurons, whereas the heat response of NS neurons was enhanced by M1-stimulation. After blocking the A11 with lidocaine or spinal D2Rs with raclopride, M1 stimulation failed to suppress the noxious heat-evoked withdrawal reflex. The results indicate that descending pain control induced by stimulation of the M1 cortex in neuropathic animals involves supraspinal (presumably striatal) and, through A11, spinal D2Rs. Supraspinal and spinal D2Rs have partly dissociative effects on spinal dorsal horn WDR and NS neurons, possibly reflecting differential roles and wirings that these sensory neurons have in pain-processing circuitries. PMID:22902996

  19. Extracellular sodium and chloride depletion enhances nonexocytotic noradrenaline release induced by energy deficiency in rat heart.

    PubMed

    Kurz, T; Schömig, A

    1989-09-01

    The effect of either extracellular sodium or extracellular chloride reduction on the release of endogenous noradrenaline and its deaminated metabolite dihydroxyphenylglycol (DOPEG) has been studied in the isolated perfused rat heart under conditions of ischaemia and cyanide intoxication. The overflow of noradrenaline and DOPEG was determined by high pressure liquid chromatography. The efflux of DOPEG, the predominant neuronal noradrenaline adrenaline metabolite, served as indicator of the free axoplasmic plasmic amine concentration. A calcium-free perfusion buffer was used to avoid exocytotic noradrenaline release. Sodium and chloride in the perfusion buffer were replaced by lithium and isethionate, respectively. (1) Reduction of extracellular sodium or chloride increased noradrenaline overflow in ischaemia. The release was suppressed by the uptake1 blocker cocaine indicating carrier-mediated outward transport of noradrenaline. (2) In cyanide intoxication sodium or chloride reduction accelerated the onset of DOPEG efflux reflecting increased axoplasmic noradrenaline concentrations. This was accompanied by increased noradrenaline release. The ratio of noradrenaline/DOPEG overflow was increased by reduced sodium or chloride, indicating facilitation of carrier-mediated noradrenaline net outward transport. (3) In the presence of unaltered energy metabolism overflow of both, noradrenaline and DOPEG, was not enhanced by sodium or chloride reduction. The results demonstrate that reduction of extracellular sodium or chloride has two effects on noradrenaline release from the sympathetic neuron with reduced energy supply. First, reduced sodium or chloride induces increased axoplasmic noradrenaline concentrations by interference with vesicular storage function. Second, both interventions enhance carrier-mediated noradrenaline release. PMID:2812038

  20. FAS-Based Cell Depletion Facilitates the Selective Isolation of Mouse Induced Pluripotent Stem Cells

    PubMed Central

    Warlich, Eva; Schambach, Axel; Lock, Dominik; Wedekind, Dirk; Glage, Silke; Eckardt, Dominik; Bosio, Andreas; Knbel, Sebastian

    2014-01-01

    Cellular reprogramming of somatic cells into induced pluripotent stem cells (iPSC) opens up new avenues for basic research and regenerative medicine. However, the low efficiency of the procedure remains a major limitation. To identify iPSC, many studies to date relied on the activation of pluripotency-associated transcription factors. Such strategies are either retrospective or depend on genetically modified reporter cells. We aimed at identifying naturally occurring surface proteins in a systematic approach, focusing on antibody-targeted markers to enable live-cell identification and selective isolation. We tested 170 antibodies for differential expression between mouse embryonic fibroblasts (MEF) and mouse pluripotent stem cells (PSC). Differentially expressed markers were evaluated for their ability to identify and isolate iPSC in reprogramming cultures. Epithelial cell adhesion molecule (EPCAM) and stage-specific embryonic antigen 1 (SSEA1) were upregulated early during reprogramming and enabled enrichment of OCT4 expressing cells by magnetic cell sorting. Downregulation of somatic marker FAS was equally suitable to enrich OCT4 expressing cells, which has not been described so far. Furthermore, FAS downregulation correlated with viral transgene silencing. Finally, using the marker SSEA-1 we exemplified that magnetic separation enables the establishment of bona fide iPSC and propose strategies to enrich iPSC from a variety of human source tissues. PMID:25029550

  1. Possible role of mtDNA depletion and respiratory chain defects in aristolochic acid I-induced acute nephrotoxicity

    SciTech Connect

    Jiang, Zhenzhou Bao, Qingli Sun, Lixin Huang, Xin Wang, Tao Zhang, Shuang Li, Han Zhang, Luyong

    2013-01-15

    This report describes an investigation of the pathological mechanism of acute renal failure caused by toxic tubular necrosis after treatment with aristolochic acid I (AAI) in Sprague–Dawley (SD) rats. The rats were gavaged with AAI at 0, 5, 20, or 80 mg/kg/day for 7 days. The pathologic examination of the kidneys showed severe acute tubular degenerative changes primarily affecting the proximal tubules. Supporting these results, we detected significantly increased concentrations of blood urea nitrogen (BUN) and creatinine (Cr) in the rats treated with AAI, indicating damage to the kidneys. Ultrastructural examination showed that proximal tubular mitochondria were extremely enlarged and dysmorphic with loss and disorientation of their cristae. Mitochondrial function analysis revealed that the two indicators for mitochondrial energy metabolism, the respiratory control ratio (RCR) and ATP content, were reduced in a dose-dependent manner after AAI treatment. The RCR in the presence of substrates for complex I was reduced more significantly than in the presence of substrates for complex II. In additional experiments, the activity of respiratory complex I, which is partly encoded by mitochondrial DNA (mtDNA), was more significantly impaired than that of respiratory complex II, which is completely encoded by nuclear DNA (nDNA). A real-time PCR assay revealed a marked reduction of mtDNA in the kidneys treated with AAI. Taken together, these results suggested that mtDNA depletion and respiratory chain defects play critical roles in the pathogenesis of kidney injury induced by AAI, and that the same processes might contribute to aristolochic acid-induced nephrotoxicity in humans. -- Highlights: ► AAI-induced acute renal failure in rats and the proximal tubule was the target. ► Tubular mitochondria were morphologically aberrant in ultrastructural examination. ► AAI impair mitochondrial bioenergetic function and mtDNA replication.

  2. Importance of cholesterol in dopamine transporter function

    PubMed Central

    Jones, Kymry T.; Zhen, Juan; Reith, Maarten E.A.

    2012-01-01

    The conformation and function of the dopamine transporter (DAT) can be affected by manipulating membrane cholesterol, yet there is no agreement as to the impact of cholesterol on the activity of lipid-raft localized DATs compared to non-raft DATs. Given the paucity of information regarding the impact of cholesterol on substrate efflux by the DAT, this study explores its influence on the kinetics of DAT-mediated DA efflux induced by dextroamphetamine, as measured by rotating disk electrode voltammetry (RDEV). Treatment with methyl-?-cyclodextrin (m?CD), which effectively depletes total membrane cholesterol- uniformly affecting cholesterol-DAT interactions in both raft and non-raft membrane domains- reduced both DA uptake and efflux rate. In contrast, disruption of raft localized DAT by cholesterol chelation with nystatin had no effect, arguing against a vital role for raft-localized DAT in substrate uptake or efflux. Supra-normal repletion of cholesterol depleted cells with the analogue desmosterol, a non-raft promoting sterol, was as effective as cholesterol itself in restoring transport rates. Further studies with Zn2+ and the conformationally-biased W84L DAT mutant supported the idea that cholesterol is important for maintaining the outward-facing DAT with normal rates of conformational interconversions. Collectively, these results point to a role for direct cholesterol-DAT interactions in regulating DAT function. PMID:22957537

  3. Reduced Insulin Sensitivity Is Related to Less Endogenous Dopamine at D2/3 Receptors in the Ventral Striatum of Healthy Nonobese Humans

    PubMed Central

    Caravaggio, Fernando; Borlido, Carol; Hahn, Margaret; Feng, Zhe; Fervaha, Gagan; Gerretsen, Philip; Nakajima, Shinichiro; Plitman, Eric; Chung, Jun Ku; Iwata, Yusuke; Wilson, Alan; Remington, Gary

    2015-01-01

    Background: Food addiction is a debated topic in neuroscience. Evidence suggests diabetes is related to reduced basal dopamine levels in the nucleus accumbens, similar to persons with drug addiction. It is unknown whether insulin sensitivity is related to endogenous dopamine levels in the ventral striatum of humans. We examined this using the agonist dopamine D2/3 receptor radiotracer [11C]-(+)-PHNO and an acute dopamine depletion challenge. In a separate sample of healthy persons, we examined whether dopamine depletion could alter insulin sensitivity. Methods: Insulin sensitivity was estimated for each subject from fasting plasma glucose and insulin using the Homeostasis Model Assessment II. Eleven healthy nonobese and nondiabetic persons (3 female) provided a baseline [11C]-(+)-PHNO scan, 9 of which provided a scan under dopamine depletion, allowing estimates of endogenous dopamine at dopamine D2/3 receptor. Dopamine depletion was achieved via alpha-methyl-para-tyrosine (64mg/kg, P.O.). In 25 healthy persons (9 female), fasting plasma and glucose was acquired before and after dopamine depletion. Results: Endogenous dopamine at ventral striatum dopamine D2/3 receptor was positively correlated with insulin sensitivity (r(7)=.84, P=.005) and negatively correlated with insulin levels (r(7)=-.85, P=.004). Glucose levels were not correlated with endogenous dopamine at ventral striatum dopamine D2/3 receptor (r(7)=-.49, P=.18). Consistently, acute dopamine depletion in healthy persons significantly decreased insulin sensitivity (t(24)=2.82, P=.01), increased insulin levels (t(24)=-2.62, P=.01), and did not change glucose levels (t(24)=-0.93, P=.36). Conclusion: In healthy individuals, diminished insulin sensitivity is related to less endogenous dopamine at dopamine D2/3 receptor in the ventral striatum. Moreover, acute dopamine depletion reduces insulin sensitivity. These findings may have important implications for neuropsychiatric populations with metabolic abnormalities. PMID:25716779

  4. Ethanol Facilitates Glutamatergic Transmission to Dopamine Neurons in the Ventral Tegmental Area

    PubMed Central

    Xiao, Cheng; Shao, Xuesi Max; Olive, M Foster; Griffin, William C; Li, Ke-Yong; Krnjevi?, Kresimir; Zhou, Chunyi; Ye, Jiang-Hong

    2009-01-01

    The cellular mechanisms underlying alcohol addiction are poorly understood. In several brain areas, ethanol depresses glutamatergic excitatory transmission, but how it affects excitatory synapses on dopamine neurons of the ventral tegmental area (VTA), a crucial site for the development of drug addiction, is not known. We report here that in midbrain slices from rats, clinically relevant concentrations of ethanol (1080 mM) increase the amplitude of evoked EPSCs and reduce their paired-pulse ratio in dopamine neurons in the VTA. The EPSCs were mediated by glutamate ?-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptors. In addition, ethanol increases the frequency but not the amplitude of spontaneous EPSCs. Furthermore, ethanol increases extracellular glutamate levels in the VTA of midbrain slices. The effects of ethanol are mimicked by SKF 38393, a dopamine D1 receptor agonist, and by GBR 12935, a dopamine reuptake inhibitor, and they are blocked by SKF 83566, a D1 antagonist, or by reserpine, which depletes dopamine stores. The enhancement of sEPSC frequency reaches a peak with 40mM ethanol and declines with concentrations ?80mM ethanol, which is quite likely a result of D2 receptor activation as raclopride, a D2 receptor blocker, significantly enhanced 80mM ethanol-induced enhancement of sEPSCs. Finally, 6, 7-dinitroquinoxaline-2, 3-dione (DNQX), an AMPA receptor antagonist, attenuates ethanol-induced excitation of VTA DA neurons. We therefore conclude that, acting via presynaptic D1 receptors, ethanol at low concentrations increases glutamate release in the VTA, thus raising somatodendritic dopamine release, which further activates the presynaptic D1 receptors. Enhancement of this positive feedback loop may significantly contribute to the development of alcohol addiction. PMID:18596684

  5. Suppression of Induced microRNA-15b Prevents Rapid Loss of Cardiac Function in a Dicer Depleted Model of Cardiac Dysfunction

    PubMed Central

    Gnyawali, Surya C.; Khanna, Savita; He, Guanglong; Pfeiffer, Douglas; Zweier, Jay L.; Sen, Chandan K.

    2013-01-01

    Background Dicer endonuclease, critical for maturation of miRNAs, is depleted in certain forms of cardiomyopathy which results in differential expression of certain microRNAs. We sought to elucidate the mechanisms underlying the rapid loss of cardiac function following cardiac-specific Dicer depletion in adult mice. Results Conditional Dicer deletion in the adult murine myocardium demonstrated compromised heart function, mitochondrial dysfunction and oxidant stress. Elevated miR-15b was observed as an early response to Dicer depletion and was found to silence Pim-1 kinase, a protein responsible for maintaining mitochondrial integrity and function. Anti-miRNA based suppression of induced miRNA-15b rescued the function of Dicer-depleted adult heart and attenuated hypertrophy. Conclusions Anti-miRNA based suppression of inducible miRNA-15b can prevent rapid loss of cardiac function in a Dicer-depleted adult heart and can be a key approach worthy of therapeutic consideration. PMID:23840532

  6. Effect of certain toxicants on gonadotropin-induced ovarian non-esterified cholesterol depletion and steroidogenic enzyme stimulation of the common carp Cyprinus carpio in vitro

    SciTech Connect

    Mukherjee, D.; Guha, D.; Kumar, V. )

    1992-06-01

    Isolated ovarian tissues from the common carp, Cyprinus carpio were incubated in vitro to obtain a discrete effect of four common toxicants of industrial origin, namely phenol, sulfide, mercuric chloride and cadmium chloride, on gonadotropin-induced alteration of nonesterified and esterified cholesterol and steroidogenic enzymes, delta 5-3 beta-HSD and 17 beta-HSD activity. Stage II ovarian tissue containing 30-40% mature oocytes were shown to be most responsive to gonadotropins in depleting only nonesterified cholesterol moiety and stimulating the activity of both. Safe doses of above mentioned toxicants when added separately to stage II ovarian tissue with oLH (1 microgram/incubation) gonadotropin-induced depletion of nonesterified cholesterol and gonadotropin-induced stimulation of the activity of both enzymes was significantly inhibited. Esterified cholesterol remained almost unaltered. Findings clearly indicate the impairment of gonadotropin induced fish ovarian steroidogenesis by the four toxicants separately.

  7. Dopamine modulates female sexual receptivity in Drosophila melanogaster.

    PubMed

    Neckameyer, W S

    1998-03-01

    Newly eclosed Drosophila melanogaster flies were systemically depleted of dopamine by feeding an inhibitor of the biosynthetic enzyme, tyrosine hydroxylase, and analyzed for abnormalities in courtship behavior. Dopamine-depleted females were significantly less receptive to males than were control females, although males were strongly attracted to treated females. The decrease in receptivity was reversed by the addition of L-DOPA (the product of the tyrosine hydroxylation reaction) to food containing the inhibitor. Male courtship behaviors were unaffected by this treatment. Female receptivity may be regulated via interactions with hormonal pathways, since depletion of dopamine levels via inhibition of tyrosine hydroxylase activity in Drosophila melanogaster adult females has established that dopamine is required for normal ovarian maturation and fecundity. PMID:10197160

  8. Prevention of immunodeficiency virus induced CD4+ T-cell depletion by prior infection with a non-pathogenic virus

    SciTech Connect

    TerWee, Julie A.; Carlson, Jennifer K.; Sprague, Wendy S.; Sondgeroth, Kerry S.; Shropshire, Sarah B.; Troyer, Jennifer L.; VandeWoude, Sue

    2008-07-20

    Immune dysregulation initiated by a profound loss of CD4+ T-cells is fundamental to HIV-induced pathogenesis. Infection of domestic cats with a non-pathogenic lentivirus prevalent in the puma (puma lentivirus, PLV or FIV{sub PCO}) prevented peripheral blood CD4+ T-cell depletion caused by subsequent virulent FIV infection. Maintenance of this critical population was not associated with a significant decrease in FIV viremia, lending support to the hypothesis that direct viral cytopathic effect is not the primary cause of immunodeficiency. Although this approach was analogous to immunization with a modified live vaccine, correlates of immunity such as a serum-neutralizing antibody or virus-specific T-cell proliferative response were not found in protected animals. Differences in cytokine transcription profile, most notably in interferon gamma, were observed between the protected and unprotected groups. These data provide support for the importance of non-adaptive enhancement of the immune response in the prevention of CD4+ T-cell loss.

  9. Calcium Inhibits Promotion by Hot Dog of 1,2-Dimethylhydrazine-Induced Mucin-Depleted Foci in Rat Colon

    PubMed Central

    Santarelli, Raphaelle L.; Naud, Nathalie; Tach, Sylviane; Guraud, Franoise; Vendeuvre, Jean-Luc; Zhou, Lin; Anwar, Muhammad M.; Mirvish, Sidney S.; Corpet, Denis E.; Pierre, Fabrice H.F.

    2013-01-01

    Epidemiology suggests that processed meat is associated with colorectal cancer risk, but few experimental studies support this association. We have shown that a model of cured meat made in a pilot workshop promotes preneoplastic lesions, mucin-depleted foci (MDF) in the colon of rats. This study had two aims: to check if real store-bought processed meats also promote MDF, and to test if calcium carbonate, which suppresses heme-induced promotion, can suppress promotion by processed meat. A 14-day study was done to test the effect of nine purchased cured meats on fecal and urinary biomarkers associated with heme-induced carcinogenesis promotion. Fecal water from rats given hot dog or fermented raw dry sausage was particularly cytotoxic. These two cured meats were thus given to rats pretreated with 1,2-dimethylhydrazine, to evaluate their effect on colorectal carcinogenesis. After a 100-d feeding period, fecal apparent total N-nitroso compounds (ATNC) were assayed and colons were scored for MDF. Hot dog diet increased fecal ATNC and the number of MDF per colon compared with the no-meat control diet (3.01.7 vs. 1.21.4, P<0.05). In a third study, addition of calcium carbonate (150 ?mol/g) to the hot dog diet decreased the number of MDF/colon and fecal ATNC compared with the hot dog diet without calcium carbonate (1.2 1.1 vs. 2.3 1.4, respectively, P<0.05). This is the first experimental evidence that a widely consumed processed meat promotes colon carcinogenesis in rats. It also shows that dietary prevention of this detrimental effect is possible. PMID:23712585

  10. Na+ appetite induced by depleting extracellular fluid volume activates the enkephalin/mu-opioid receptor system in the rat forebrain.

    PubMed

    Grondin, M-E; Gobeil-Simard, A; Drolet, G; Mouginot, D

    2011-09-29

    In Na(+) appetite neurobiology, it is essential to investigate whether endogenous opioids modulate the output of the neural substrates that are involved in both the detection and integration of Na(+) deficiency and the motivational aspect of Na(+) intake. Thus, evaluating the recruitment dynamics of enkephalin (ENK)-containing and/or mu-opioid receptor (μ-OR)-expressing neurons in close correlation with the hydromineral state of the rat might provide useful information regarding the role of the opioid system in regulating the central network that controls water and Na(+) intake. Furosemide was used to deplete both fluid volume and the Na(+) content of the extracellular fluid (ECF) compartment when combined with water repletion and a short-term Na(+)-free diet. Na(+) restoration in the ECF compartment was achieved by providing unrestricted access to both saline (0.3 M NaCl) and water. Combining in situ hybridization (against ENK and μ-OR mRNA) and immunohistochemistry (against Fos) revealed a specific pattern of hypovolemia-induced Fos expression in the enkephalinergic subpopulations of the central amygdala, in the oval nucleus of the bed nucleus of the stria terminalis and in the nucleus accumbens shell. Hypovolemia also induced transient Fos expression in μ-OR-expressing neurons in the same nuclei and in the median preoptic nucleus and subfornical organ. However, this specific hydromineral state did not activate the ENK and/or μ-OR-expressing neurons in the lateral parabrachial nucleus or in the medial nucleus of the solitary tract. These results implicate the ENK/μ-OR system as a putative facilitator of Na(+) intake in discrete regions of the forebrain, possibly by modulating the hedonic and reward value of Na(+) by increasing ENK release in these regions. PMID:21745545

  11. Experimentally-induced immune activation in natural hosts of SIV induces significant increases in viral replication and CD4+ T cell depletion

    SciTech Connect

    Ribeiro, Ruy M

    2008-01-01

    Chronically SIVagm-infected African green monkeys (AGMs) have a remarkably stable non-pathogenic disease course, with levels of immune activation in chronic SIVagm infection similar to those observed in uninfected monkeys and stable viral loads (VLs) for long periods of time. In vivo administration of lipopolysaccharide (LPS) or an IL-2/diphtheria toxin fusion protein (Ontak) to chronically SIVagm-infected AGMs triggered increases in immune activation and subsequently of viral replication and depletion of intestinal CD4{sup +} T cells. Our study indicates that circulating microbial products can increase viral replication by inducing immune activation and increasing the number of viral target cells, thus demonstrating that immune activation and T cell prolifeation are key factors in AIDS pathogenesis.

  12. Dopamine-Independent Locomotor Actions of Amphetamines in a Novel Acute Mouse Model of Parkinson Disease

    PubMed Central

    2005-01-01

    Brain dopamine is critically involved in movement control, and its deficiency is the primary cause of motor symptoms in Parkinson disease. Here we report development of an animal model of acute severe dopamine deficiency by using mice lacking the dopamine transporter. In the absence of transporter-mediated recycling mechanisms, dopamine levels become entirely dependent on de novo synthesis. Acute pharmacological inhibition of dopamine synthesis in these mice induces transient elimination of striatal dopamine accompanied by the development of a striking behavioral phenotype manifested as severe akinesia, rigidity, tremor, and ptosis. This phenotype can be reversed by administration of the dopamine precursor, L-DOPA, or by nonselective dopamine agonists. Surprisingly, several amphetamine derivatives were also effective in reversing these behavioral abnormalities in a dopamine-independent manner. Identification of dopamine transporter- and dopamine-independent locomotor actions of amphetamines suggests a novel paradigm in the search for prospective anti-Parkinsonian drugs. PMID:16050778

  13. Effects of Enzyme Induction and/or Glutathione Depletion on Methimazole-Induced Hepatotoxicity in Mice and the Protective Role of N-Acetylcysteine

    PubMed Central

    Heidari, Reza; Babaei, Hossein; Roshangar, Leila; Eghbal, Mohammad Ali

    2014-01-01

    Purpose: Methimazole is the most convenient drug used in the management of hyperthyroid patients. However, associated with its clinical use is hepatotoxicity as a life threatening adverse effect. The exact mechanism of methimazole-induced hepatotoxicity is still far from clear and no protective agent has been developed for this toxicity. Methods: This study attempts to evaluate the hepatotoxicity induced by methimazole at different experimental conditions in a mice model. Methimazole-induced hepatotoxicity was investigated in different situations such as enzyme induced and/or glutathione depleted animals. Results: Methimazole (100 mg/kg, i.p) administration caused hepatotoxicity as revealed by increase in serum alanine aminotransferase (ALT) activity as well as pathological changes of the liver. Furthermore, a significant reduction in hepatic glutathione content and an elevation in lipid peroxidation were observed in methimazole-treated mice. Combined administration of L-buthionine sulfoximine (BSO), as a glutathione depletory agent, caused a dramatic change in methimazole-induced hepatotoxicity characterized by hepatic necrosis and a severe elevation of serum ALT activity. Enzyme induction using phenobarbital and/or β-naphtoflavone beforehand, deteriorated methimazole-induced hepatotoxicity in mice. N-acetyl cysteine (300 mg/kg, i.p) administration effectively alleviated hepatotoxic effects of methimazole in both glutathione-depleted and/or enzyme induced animals. Conclusion: The severe hepatotoxic effects of methimazole in glutathione-depleted animals, reveals the crucial role of glutathione as a cellular defense mechanism against methimazole-induced hepatotoxicity. Furthermore, the more hepatotoxic properties of methimazole in enzyme-induced mice, indicates the role of reactive intermediates in the hepatotoxicity induced by this drug. The protective effects of N-acetylcysteine could be attributed to its radical/reactive metabolite scavenging, and/or antioxidant properties as well as glutathione replenishment activities. PMID:24409405

  14. Neuroprotection and dopamine agonists.

    PubMed

    Schapira, Anthony H V

    2002-02-26

    Several factors are known to be capable of inducing relatively selective dopaminergic cell death in the substantia nigra and inducing the clinical features that characterize Parkinson's disease (PD). Neuronal toxins such as 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) can induce parkinsonism in human and animal models, and rotenone, another specific mitochondrial complex I inhibitor, can induce similar effects in rodents to produce a model for PD. Studies in twins suggest a significant genetic component to young-onset PD, and several gene mutations have now been identified as causing familial autosomal dominant or autosomal recessive PD. Etiologic factors including free radical-mediated damage (including excitotoxicity), mitochondrial dysfunction, and inflammation-mediated cell damage can contribute to pathogenesis. In addition, the recent interest in protein misfolding, aggregation, and proteosomal activity has provided further insight into potential pathogenetic pathways in PD. Against this background there has been increasing interest in the development of drugs to modify these biochemical abnormalities and thus alter the course of PD, either by retarding the rate of cell death or by restoring function to neurons that are likely to be damaged but not dead. In this context, dopamine agonists have shown significant promise. Not only do these drugs provide symptomatic relief of PD but they also appear to be associated with a significant decrease in the rate of motor complications and to be capable of protecting against some of the adverse consequences of levodopa use. However, evidence is now emerging that dopamine agonists may have additional neuroprotective properties. As a group, they have antioxidant actions in vitro and in vivo. More specifically, the D(2)/D(3) dopamine agonist pramipexole may have neuroprotective activity that is, at least in part, unrelated to its dopamine agonist action. Protection in cell and animal models against a variety of toxins, including MPTP and 6-hydroxydopamine, confirms that this agonist has in vitro and in vivo neuroprotective action. Evidence is now emerging that some of this may be mediated by direct action on mitochondrial membrane potential and the inhibition of apoptosis. If the neuroprotective action of this drug is confirmed in patients with PD, this will have important implications for its early use in patients. PMID:11909981

  15. Mice transgenic for exon 1 of the Huntington's disease gene display reduced striatal sensitivity to neurotoxicity induced by dopamine and 6-hydroxydopamine.

    PubMed

    Petersn, A; Hansson, O; Puschban, Z; Sapp, E; Romero, N; Castilho, R F; Sulzer, D; Rice, M; DiFiglia, M; Przedborski, S; Brundin, P

    2001-11-01

    Huntington's disease is an autosomal dominant hereditary neurodegenerative disorder characterized by severe striatal cell loss. Dopamine (DA) has been suggested to play a role in the pathogenesis of the disease. We have previously reported that transgenic mice expressing exon 1 of the human Huntington gene (R6 lines) are resistant to quinolinic acid-induced striatal toxicity. In this study we show that with increasing age, R6/1 and R6/2 mice develop partial resistance to DA- and 6-hydroxydopamine-mediated toxicity in the striatum. Using electron microscopy, we found that the resistance is localized to the cell bodies and not to the neuropil. The reduction of dopamine and cAMP regulated phosphoprotein of a molecular weight of 32 kDa (DARPP-32) in R6/2 mice does not provide the resistance, as DA-induced striatal lesions are not reduced in size in DARPP-32 knockout mice. Neither DA receptor antagonists nor a N-methyl-d-aspartate (NMDA) receptor blocker reduce the size of DA-induced striatal lesions, suggesting that DA toxicity is not dependent upon DA- or NMDA receptor-mediated pathways. Moreover, superoxide dismutase-1 overexpression, monoamine oxidase inhibition and the treatment with the free radical scavenging spin-trap agent phenyl-butyl-tert-nitrone (PBN) also did not block DA toxicity. Levels of the antioxidant molecules, glutathione and ascorbate were not increased in R6/1 mice. Because damage to striatal neurons following intrastriatal injection of 6-hydroxydopamine was also reduced in R6 mice, a yet-to-be identified antioxidant mechanism may provide neuroprotection in these animals. We conclude that striatal neurons of R6 mice develop resistance to DA-induced toxicity with age. PMID:11722604

  16. The role of dopamine D2, but not D3 or D4, receptor subtypes, in quinpirole-induced inhibition of the cardioaccelerator sympathetic outflow in pithed rats

    PubMed Central

    Altamirano-Espinoza, A H; Gonzlez-Hernndez, A; Manrique-Maldonado, G; Marichal-Cancino, B A; Ruiz-Salinas, I; Villaln, C M

    2013-01-01

    Background and Purpose Quinpirole (a dopamine D2-like receptor agonist) inhibits the cardioaccelerator sympathetic outflow in pithed rats by sympathoinhibitory D2-like receptors. The present study was designed to identify pharmacologically the specific D2-like receptor subtypes (i.e. D2, D3 and D4) involved in this sympathoinhibition by quinpirole. Experimental Approach One hundred fourteen male Wistar rats were pithed, artificially ventilated with room air and prepared for either preganglionic spinal (C7-T1) stimulation of the cardioaccelerator sympathetic outflow (n = 102) or i.v. bolus injections of exogenous noradrenaline (n = 12). This approach resulted in frequency-dependent and dose-dependent tachycardic responses, respectively, as previously reported by our group. Key Results I.v. continuous infusions of quinpirole (0.110??g?kg?1?min?1), but not of saline (0.02?mL?min?1), dose-dependently inhibited the sympathetically induced tachycardic responses. Moreover, the cardiac sympathoinhibition induced by 3??g?kg?1?min?1 quinpirole (which failed to affect the tachycardic responses to i.v. noradrenaline) was: (i) unchanged after i.v. injections of the antagonists SB-277011-A (D3; 100300??g?kg?1) or L-745,870 (D4; 30100??g?kg?1); and (ii) markedly blocked and abolished by, respectively, 100 and 300??g?kg?1 of the D2 preferring receptor subtype antagonist L-741,626. These doses of antagonists, which did not affect per se the sympathetically induced tachycardic responses, were high enough to completely block their respective receptors. Conclusions and Implications The cardiac sympathoinhibition induced by 3??g?kg?1?min?1 quinpirole involves the dopamine D2 receptor subtype, with no evidence for the involvement of the D3 or D4 subtypes. This provides new evidence for understanding the modulation of the cardioaccelerator sympathetic outflow. PMID:24032529

  17. Role of dorsal medial prefrontal cortex dopamine D1-family receptors in relapse to high-fat food seeking induced by the anxiogenic drug yohimbine.

    PubMed

    Nair, Sunila G; Navarre, Brittany M; Cifani, Carlo; Pickens, Charles L; Bossert, Jennifer M; Shaham, Yavin

    2011-01-01

    In humans, relapse to maladaptive eating habits during dieting is often provoked by stress. In rats, the anxiogenic drug yohimbine, which causes stress-like responses in both humans and nonhumans, reinstates food seeking in a relapse model. In this study, we examined the role of medial prefrontal cortex (mPFC) dopamine D1-family receptors, previously implicated in stress-induced reinstatement of drug seeking, in yohimbine-induced reinstatement of food seeking. We trained food-restricted rats to lever press for 35% high-fat pellets every other day (9-15 sessions, 3 h each); pellet delivery was accompanied by a discrete tone-light cue. We then extinguished operant responding for 10-16 days by removing the pellets. Subsequently, we examined the effect of yohimbine (2 mg/kg, i.p.) on reinstatement of food seeking and Fos (a neuronal activity marker) induction in mPFC. We then examined the effect of systemic injections of the D1-family receptor antagonist SCH23390 (10 ?g/kg, s.c.) on yohimbine-induced reinstatement and Fos induction, and that of mPFC SCH23390 (0.5 and 1.0 ?g/side) injections on this reinstatement. Yohimbine-induced reinstatement was associated with strong Fos induction in the dorsal mPFC and with weaker Fos induction in the ventral mPFC. Systemic SCH23390 injections blocked both yohimbine-induced reinstatement and mPFC Fos induction. Dorsal, but not ventral, mPFC injections of SCH23390 decreased yohimbine-induced reinstatement of food seeking. In addition, dorsal mPFC SCH23390 injections decreased pellet-priming-induced reinstatement, but had no effect on ongoing high-fat pellet self-administration or discrete-cue-induced reinstatement. Results indicate a critical role of dorsal mPFC dopamine D1-family receptors in stress-induced relapse to palatable food seeking, as well as relapse induced by acute re-exposure to food taste, texture, and smell. PMID:20962767

  18. Role of Dorsal Medial Prefrontal Cortex Dopamine D1-Family Receptors in Relapse to High-Fat Food Seeking Induced by the Anxiogenic Drug Yohimbine

    PubMed Central

    Nair, Sunila G; Navarre, Brittany M; Cifani, Carlo; Pickens, Charles L; Bossert, Jennifer M; Shaham, Yavin

    2011-01-01

    In humans, relapse to maladaptive eating habits during dieting is often provoked by stress. In rats, the anxiogenic drug yohimbine, which causes stress-like responses in both humans and nonhumans, reinstates food seeking in a relapse model. In this study, we examined the role of medial prefrontal cortex (mPFC) dopamine D1-family receptors, previously implicated in stress-induced reinstatement of drug seeking, in yohimbine-induced reinstatement of food seeking. We trained food-restricted rats to lever press for 35% high-fat pellets every other day (915 sessions, 3?h each); pellet delivery was accompanied by a discrete tone-light cue. We then extinguished operant responding for 1016 days by removing the pellets. Subsequently, we examined the effect of yohimbine (2?mg/kg, i.p.) on reinstatement of food seeking and Fos (a neuronal activity marker) induction in mPFC. We then examined the effect of systemic injections of the D1-family receptor antagonist SCH23390 (10??g/kg, s.c.) on yohimbine-induced reinstatement and Fos induction, and that of mPFC SCH23390 (0.5 and 1.0??g/side) injections on this reinstatement. Yohimbine-induced reinstatement was associated with strong Fos induction in the dorsal mPFC and with weaker Fos induction in the ventral mPFC. Systemic SCH23390 injections blocked both yohimbine-induced reinstatement and mPFC Fos induction. Dorsal, but not ventral, mPFC injections of SCH23390 decreased yohimbine-induced reinstatement of food seeking. In addition, dorsal mPFC SCH23390 injections decreased pellet-priming-induced reinstatement, but had no effect on ongoing high-fat pellet self-administration or discrete-cue-induced reinstatement. Results indicate a critical role of dorsal mPFC dopamine D1-family receptors in stress-induced relapse to palatable food seeking, as well as relapse induced by acute re-exposure to food taste, texture, and smell. PMID:20962767

  19. Chronic treatment with novel small molecule Hsp90 inhibitors rescues striatal dopamine levels but not ?-synuclein-induced neuronal cell loss.

    TOXLINE Toxicology Bibliographic Information

    McFarland NR; Dimant H; Kibuuka L; Ebrahimi-Fakhari D; Desjardins CA; Danzer KM; Danzer M; Fan Z; Schwarzschild MA; Hirst W; McLean PJ

    2014-01-01

    Hsp90 inhibitors such as geldanamycin potently induce Hsp70 and reduce cytotoxicity due to ?-synuclein expression, although their use has been limited due to toxicity, brain permeability, and drug design. We recently described the effects of a novel class of potent, small molecule Hsp90 inhibitors in cells overexpressing ?-synuclein. Screening yielded several candidate compounds that significantly reduced ?-synuclein oligomer formation and cytotoxicity associated with Hsp70 induction. In this study we examined whether chronic treatment with candidate Hsp90 inhibitors could protect against ?-synuclein toxicity in a rat model of parkinsonism. Rats were injected unilaterally in the substantia nigra with AAV8 expressing human ?-synuclein and then treated with drug for approximately 8 weeks by oral gavage. Chronic treatment with SNX-0723 or the more potent, SNX-9114 failed to reduce dopaminergic toxicity in the substantia nigra compared to vehicle. However, SNX-9114 significantly increased striatal dopamine content suggesting a positive neuromodulatory effect on striatal terminals. Treatment was generally well tolerated, but higher dose SNX-0723 (6-10 mg/kg) resulted in systemic toxicity, weight loss, and early death. Although still limited by potential toxicity, Hsp90 inhibitors tested herein demonstrate oral efficacy and possible beneficial effects on dopamine production in a vertebrate model of parkinsonism that warrant further study.

  20. Amphetamine activates Rho GTPase signaling to mediate dopamine transporter internalization and acute behavioral effects of amphetamine.

    PubMed

    Wheeler, David S; Underhill, Suzanne M; Stolz, Donna B; Murdoch, Geoffrey H; Thiels, Edda; Romero, Guillermo; Amara, Susan G

    2015-12-22

    Acute amphetamine (AMPH) exposure elevates extracellular dopamine through a variety of mechanisms that include inhibition of dopamine reuptake, depletion of vesicular stores, and facilitation of dopamine efflux across the plasma membrane. Recent work has shown that the DAT substrate AMPH, unlike cocaine and other nontransported blockers, can also stimulate endocytosis of the plasma membrane dopamine transporter (DAT). Here, we show that when AMPH enters the cytoplasm it rapidly stimulates DAT internalization through a dynamin-dependent, clathrin-independent process. This effect, which can be observed in transfected cells, cultured dopamine neurons, and midbrain slices, is mediated by activation of the small GTPase RhoA. Inhibition of RhoA activity with C3 exotoxin or a dominant-negative RhoA blocks AMPH-induced DAT internalization. These actions depend on AMPH entry into the cell and are blocked by the DAT inhibitor cocaine. AMPH also stimulates cAMP accumulation and PKA-dependent inactivation of RhoA, thus providing a mechanism whereby PKA- and RhoA-dependent signaling pathways can interact to regulate the timing and robustness of AMPH's effects on DAT internalization. Consistent with this model, the activation of D1/D5 receptors that couple to PKA in dopamine neurons antagonizes RhoA activation, DAT internalization, and hyperlocomotion observed in mice after AMPH treatment. These observations support the existence of an unanticipated intracellular target that mediates the effects of AMPH on RhoA and cAMP signaling and suggest new pathways to target to disrupt AMPH action. PMID:26553986

  1. Kinetics of carotenoid distribution in human skin in vivo after exogenous stress: disinfectant and wIRA-induced carotenoid depletion recovers from outside to inside

    NASA Astrophysics Data System (ADS)

    Fluhr, Joachim W.; Caspers, Peter; van der Pol, J. Andre; Richter, Heike; Sterry, Wolfram; Lademann, Juergen; Darvin, Maxim E.

    2011-03-01

    The human organism has developed a protection system against the destructive effect of free radicals. The aim of the present study was to investigate the extent of exogenous stress factors such as disinfectant and IR-A radiation on the skin, and their influence on the kinetics of carotenoids distribution during the recovery process. Ten healthy volunteers were assessed with resonance spectroscopy using an Argon-laser at 488 nm to excite the carotenoids in vivo. Additionally, Raman-confocal-micro-spectroscopy measurements were performed using a model 3510 Skin Composition Analyzer with spatially resolved measurements down to 30 μm. The measurements were performed at a baseline of 20, 40, 60, and 120 min after an external stressor consisting either of water-filtered infrared A (wIRA) with 150 mW/cm2 or 1 ml/cm2 of an alcoholic disinfectant. Both Raman methods were capable to detect the infrared-induced depletion of carotenoids. Only Raman-microspectroscopy could reveal the carotenoids decrease after topical disinfectant application. The carotenoid-depletion started at the surface. After 60 min, recovery starts at the surface while deeper parts were still depleted. The disinfectant- and wIRA-induced carotenoid depletion in the epidermis recovers from outside to inside and probably delivered by sweat and sebaceous glands. We could show that the Raman microscopic spectroscopy is suited to analyze the carotenoid kinetic of stress effects and recovery.

  2. Sustained accumulation of prelamin A and depletion of lamin A/C both cause oxidative stress and mitochondrial dysfunction but induce different cell fates

    PubMed Central

    Sieprath, Tom; Corne, Tobias DJ; Nooteboom, Marco; Grootaert, Charlotte; Rajkovic, Andreja; Buysschaert, Benjamin; Robijns, Joke; Broers, Jos LV; Ramaekers, Frans CS; Koopman, Werner JH; Willems, Peter HGM; De Vos, Winnok H

    2015-01-01

    The cell nucleus is structurally and functionally organized by lamins, intermediate filament proteins that form the nuclear lamina. Point mutations in genes that encode a specific subset of lamins, the A-type lamins, cause a spectrum of diseases termed laminopathies. Recent evidence points to a role for A-type lamins in intracellular redox homeostasis. To determine whether lamin A/C depletion and prelamin A accumulation differentially induce oxidative stress, we have performed a quantitative microscopy-based analysis of reactive oxygen species (ROS) levels and mitochondrial membrane potential (Δψm) in human fibroblasts subjected to sustained siRNA-mediated knockdown of LMNA and ZMPSTE24, respectively. We measured a highly significant increase in basal ROS levels and an even more prominent rise of induced ROS levels in lamin A/C depleted cells, eventually resulting in Δψm hyperpolarization and apoptosis. Depletion of ZMPSTE24 on the other hand, triggered a senescence pathway that was associated with moderately increased ROS levels and a transient Δψm depolarization. Both knockdowns were accompanied by an upregulation of several ROS detoxifying enzymes. Taken together, our data suggest that both persistent prelamin A accumulation and lamin A/C depletion elevate ROS levels, but to a different extent and with different effects on cell fate. This may contribute to the variety of disease phenotypes witnessed in laminopathies. PMID:25996284

  3. Potential role of HPA axis and sympathetic nervous responses in depletion of B cells induced by H9N2 avian influenza virus infection.

    PubMed

    Qi, Wenbao; Tian, Jin; Zhang, Changhui; He, Jun; Ning, Zhangyong; Jiao, Peirong; Liao, Ming

    2012-01-01

    Except severe pulmonary disease caused by influenza virus infection, an impaired immune system is also a clinic characteristic. However, the mechanism(s) of influenza virus infection-induced depletion of B cells was unknown. Here, we compared the effect of two variant virulence H9N2 virus infections on mouse B cells. Our study found that the infection with highly pathogenic virus (V) of led to depletion of spleen B cells and bone marrow (BM) early B cells, compared to lowly pathogenic virus (Ts). Moreover, high apoptosis and cell cycle arrest in spleen and BM were detected, suggesting important factors for the reduction of B cells in both organs. Further, this effect was not caused by virus replication in spleen and BM. Compared to Ts virus infection, V virus resulted in higher glucocorticoids (GCs) and lower leptin level in plasma. Intraperitoneal GCs receptor antagonist RU486 injection was sufficient to prevent the loss of spleen B cell and BM pro- and immature B cells, but similar result was not observed in leptin-treated mice. Depletion of spleen B cells and BM pro-B cells was also reversed by chemical sympathectomy mediated by the norepinephrine (NE) analog 6-hydroxydopamine (6-OHDA), but the treatment didn't affect the GCs level. This study demonstrated that depletion of B cells induced by H9N2 AIV was dependent on HPA axis and sympathetic response. PMID:23251416

  4. Low doses of CMV induce autoimmune-mediated and inflammatory responses in bile duct epithelia of regulatory T cell-depleted neonatal mice.

    PubMed

    Wen, Jie; Xiao, Yongtao; Wang, Jun; Pan, Weihua; Zhou, Ying; Zhang, Xiaoling; Guan, Wenbin; Chen, Yingwei; Zhou, Kejun; Wang, Yang; Shi, Bisheng; Zhou, Xiaohui; Yuan, Zhenghong; Cai, Wei

    2015-02-01

    Recent studies have indicated that perinatal infection with cytomegalovirus (CMV) may promote bile duct damage in biliary atresia (BA) and that the decreased regulatory T cell (Treg) percentage associated with BA may further amplify the bile duct damage. Although a majority of BA patients have had previous CMV infections and lower percentages of Tregs, it is unknown whether an initial exposure to a low dose of CMV could induce exaggerated and progressive biliary injury. A Treg-depleted neonatal mouse was infected with low-dose CMV (LD-CMV) as a model to study BA patients. LD-CMV infection in Treg-depleted mice induced extensive inflammation in both the intrahepatic and extrahepatic bile ducts, accompanied with injury to and atresia of intrahepatic bile ducts and partial obstruction of the extrahepatic bile ducts. Serum total and direct bilirubin amounts were also elevated. Evidence for the involvement of cellular and humoral autoimmune responses in LD-CMV-infection of Treg-depleted mice was also obtained through detection of increased percentages of CD3 and CD8 mononuclear cells and serum autoantibodies reactive to bile duct epithelial proteins, one of which was identified as ?-enolase. Depletion of Tregs that can lead to the decreased inhibition of aberrantly activated hepatic T-lymphocytes and generation of autoantibodies may lead to further injury. Increased hepatic expression of Th1-related genes (TNF-?), IFN-?-activated genes (STAT-1) and Th1 cytokines (TNF-?, lymphotactin, IL-12p40 and MIP -1?) were also identified. In conclusion, autoimmune-mediated and inflammatory responses induced by LD-CMV infection in Treg-depleted mice results in increased intrahepatic and extrahepatic bile duct injury and contributed to disease progression. PMID:25531565

  5. Iron-induced accumulation of hepatic zinc metallothionein: a marked diminution by short-term dietary zinc depletion

    SciTech Connect

    McCormick, C.C.

    1986-03-05

    Studies were conducted to determine the effect of zinc depletion on the accumulation of hepatic zinc metallothionein (ZnMT) induced by iron loading. Four-week-old chicks were fed a zinc-deficient diet (-Zn, 1.4 ppm Zn) for 6 days prior to iron loading. Iron loading was accomplished by two injections (i.p.) at 24-hour intervals of ferric chloride at 10 mg Fe/kg BW. Control chicks received an equal volume of saline in conjunction with either -Zn or zinc-sufficient diet (+Zn, 64 ppm Zn). Within 24 hours of feeding -Zn, plasma zinc decreased to approximately 30% of control values and remained at this level for the remaining period. Neither feed consumption nor bodyweight gain was affected by -Zn. Iron loading decreased plasma zinc (40%) in +Zn chicks and caused a similar reduction in feed consumption for both - and + Zn chicks. ZnMT was not detectable (by G-75 chromatography) in -Zn saline-treated chicks but was estimated to be 1.4 +/- 0.2 ..mu..g Zn/ml cytosol for +Zn chicks. Values for + and - Zn iron-loaded chicks were 8.9 +/- 2.5 and 1.8 +/- 0.6. The concentration of hepatic ZnMT in the various groups was confirmed by gel electrophoresis. Similar results were obtained when -Zn diets were fed for 2 days prior to iron loading. The results indicate that plasma zinc is an important component in the process by which parenteral iron effects an accumulation of hepatic ZnMT.

  6. Reserpine-induced up-regulation of dopamine D2 receptors in the rat striatum is enhanced by denervation but not by chronic receptor blockade.

    PubMed

    Traub, M; Reches, A; Wagner, H R; Fahn, S

    1986-10-01

    Compensatory increases in the density of dopamine (DA) D2 receptors in the rat striatum occur following chronic interruption of dopaminergic neurotransmission. Substantia nigra lesions, DA depletion with reserpine and D2 receptor blockade by neuroleptics increase the number of striatal D2 receptors as identified with the D2 ligand, [3H]spiperone [( 3H]SPIP). Chronic administration of haloperidol to substantia nigra-lesioned rats causes an additive increase in binding over levels obtained with one treatment alone. In this study we have found a similar response when lesioned animals are treated with reserpine. However, compensatory increases in the number of [3H]SPIP binding sites found after combined administration of reserpine and haloperidol to intact rats do not exceed levels obtained following administration of either drug alone. The data suggest that up-regulation of striatal D2 binding sites occurring after substantia nigra lesions is unique relative to other forms of up-regulation and may involve the loss of a presynaptic regulatory factor other than DA. PMID:2946007

  7. A paradoxical regulation of the dopamine D3 receptor expression suggests the involvement of an anterograde factor from dopamine neurons.

    PubMed Central

    Lévesque, D; Martres, M P; Diaz, J; Griffon, N; Lammers, C H; Sokoloff, P; Schwartz, J C

    1995-01-01

    The effects of interruption of dopaminergic transmission or sustained blockade of dopamine receptors by neuroleptics on the dopamine D3 receptor in the shell of the nucleus accumbens were investigated in rats. In this brain area the D3 receptor is abundant and may mediate antipsychotic drug effects. The D3 receptor density and mRNA abundance were evaluated with 7-[3H]hydroxy-N,N-di-n-propyl-2-aminotetralin and by quantitative PCR or image analysis of in situ hybridization signals, respectively. Unilateral dopamine neuron degeneration by 6-hydroxydopamine or sections triggered, after a few days, a marked decrease (up to 50%) in D3 receptor binding and mRNA in the nucleus accumbens. In contrast, a 2-week treatment with the neuroleptic haloperidol (20 mg/kg) had no effect on D3 rece