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Search Results: 1 - 10 of 642 matches for " nucleus accumbens "
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Further studies on the effects of acamprosate on tolerance to the analgesic effects of morphine and NO synthesis in the brain  [PDF]
Jacqueline Sepúlveda, Andrea Ortega, Jorge Roa, Enrique Contreras
Health (Health) , 2013, DOI: 10.4236/health.2013.511A1001
Abstract: The aim of this work was to investigate whether acamprosate modifies the expression of the enzyme responsible for neuronal NO synthesis (nNOS) in the nucleus accumbens (NAc) of mice chronically treated with morphine and during the abstinence syndrome induced by naloxone. The enzyme was monitored by the NADPH diaphorase method. The number of cells stained for NADPH diaphorase in the NAc of mice was counted in 40 μm thick coronal brain slices at 40X. The intensity of the histochemical reaction of stained cells from naive morphine plus saline and morphine plus acamprosate treated mice was analyzed by Image Pro Plus 4.5.1. Morphine administered in a slow release preparation increased the stain intensity of the positive neurons. The increase in the NADPH staining persisted after naloxone was given to mice chronically treated with morphine. Acamprosate antagonized the effects induced by chronic morphine treatment in the NAc of mice. These results indicate that up-regulation of nNOS in the NAc is a consequence of the sustained effects of morphine stimulation, which, in turn, may result from an increased in glutamate release during the abstinence syndrome.
Neural Activation by Milnacipran and Memory Extinction  [PDF]
Hisahito Ishida, Masaaki Iwata, Yukihiko Shirayama, Katsumasa Muneoka
Journal of Behavioral and Brain Science (JBBS) , 2012, DOI: 10.4236/jbbs.2012.22016
Abstract: Background: Among neurotransmitter influencing memory formation, the noradrenergic system has been recognized as an important system. Memory formation involves various regions including the prefrontal cortex, hippocampus, amygdala and septum. Method: We investigated the effects of milnacipran on passive avoidance task and evaluated Fos counting in the prefrontal cortex, hippocampus, septum, amygdala and nucleus accumbens. Results: The milnacipran-treated rats (20 mg/kg, 4 days) showed a significant decrease in the number of Fos-immunoreactive cells in the infralimbic portion of prefrontal cortex, the shell portion of nucleus accumbens and the CA1 region of hippocampus, but a significant increase in the Fos counts in the lateral septum with no changes in the Fos counts in the striatum and amygdala. The milnacipran-treated rats showed amelioration in memory extinction (although not statistically significant), but not in memory acquisition and consolidation in the passive avoidance test. Conclusion: The differential activation of the brain regions might be possible sites for ameliorating memory extinction as well as antidepressant effects.
DNA methylation of the Monoamine Oxidases A and B genes in postmortem brains of subjects with schizophrenia  [PDF]
Qiaohui Yang, Keiko Ikemoto, Satoshi Nishino, Junko Yamaki, Yasuto Kunii, Akira Wada, Yoshimi Homma, Shin-Ichi Niwa
Open Journal of Psychiatry (OJPsych) , 2012, DOI: 10.4236/ojpsych.2012.224053
Abstract: Aims: We focused on DNA methylation of the promoter regions of the Monoamine Oxidase (MAO) A and B genes from postmortem brains of subjects with schizophrenia. Methods: We determined levels of DNA methylation using genomic DNA samples purified from four brain areas: prefrontal cortex (PFC), hippocampus, occipital cortex and nucleus accumbens (NAc), by a bisulfite sequencing method from seven normal subjects and six subjects with schizophrenia. Results: Although very few methylated CpGs of the MAOA and MAOB genes were detected in male samples, various DNA methylation patterns were present in female samples, and some differences were found in such patterns between normal subjects and subjects with schizophrenia. In the PFC, the average level of methylation of both genes was significantly higher in subjects with schizophrenia than in normal subjects. The content of highly methylated alleles of the MAOA gene in the NAc was significantly associated with schizophrenia, with similar results obtained for the MAOB gene in both the NAc and PFC. Some CpG sites showed higher levels of methylation in schizophrenia than in normal subjects. Conclusions: Levels of methylation were quite high in NAc and PFC in female subjects with schizophrenia compared with those in female normal subjects.
Local infusion of low, but not high, doses of alcohol into the anterior ventral tegmental area causes release of accumbal dopamine  [PDF]
Elisabet Jerlhag, J?rgen A. Engel
Open Journal of Psychiatry (OJPsych) , 2014, DOI: 10.4236/ojpsych.2014.41008

The mesolimbic dopamine system consisting of dopaminergic neurons projecting from the ventral tegmental area (VTA) to the nucleus accumbens (N.Acc.) mediates the reinforcing effects of addictive drugs including alcohol. Given that VTA is a heterogeneous area and that alcohol, in rather low doses, interacts directly with ligand-gated ion channels, we hypothesised that low, rather than high, doses of alcohol into the VTA activate the mesolimbic dopamine system and that alcohol may have different effects in the anterior and posterior parts of the VTA. The present study was undertaken to investigate this hypothesis. The present series of experiment show that infusion of a low dose of alcohol (20 mM) into the anterior, but not posterior, part of the VTA increases accumbal dopamine release in rats. In addition, higher doses of alcohol (100 or 300 mM) into the anterior or posterior part of the VTA do not affect the release of dopamine in the N.Acc., suggesting that low doses of alcohol can activate the mesolimbic dopamine system via mechanisms in the VTA. These data contribute to understanding the neuronal mechanisms underlying the dependence-producing properties of alcohol and could tentatively contribute to that new treatment strategies for alcohol use disorder can be developed.

Cocaine-Induced Reinstatement of a Conditioned Place Preference in Developing Rats: Involvement of the D2 Receptor
Kimberly A. Badanich,Cheryl L. Kirstein
Brain Sciences , 2012, DOI: 10.3390/brainsci2040573
Abstract: Reinstatement of conditioned place preferences have been used to investigate physiological mechanisms mediating drug-seeking behavior in adolescent and adult rodents; however, it is still unclear how psychostimulant exposure during adolescence affects neuron communication and whether these changes would elicit enhanced drug-seeking behavior later in adulthood. The present study determined whether the effects of intra-ventral tegmental area (VTA) or intra-nucleus accumbens septi (NAcc) dopamine (DA) D2 receptor antagonist infusions would block (or potentiate) cocaine-induced reinstatement of conditioned place preferences. Adolescent rats (postnatal day (PND 28–39)) were trained to express a cocaine place preference. The involvement of D2 receptors on cocaine-induced reinstatement was determined by intra-VTA or intra-NAcc infusion of the DA D2 receptor antagonist sulpiride (100 μM) during a cocaine-primed reinstatement test (10 mg/kg cocaine, i.p.). Infusion of sulpiride into the VTA but not the NAcc blocked reinstatement of conditioned place preference. These data suggest intrinsic compensatory mechanisms in the mesolimbic DA pathway mediate responsivity to cocaine-induced reinstatement of a conditioned place preference during development.
Reward circuitry dysfunction in psychiatric and neurodevelopmental disorders and genetic syndromes: animal models and clinical findings
Gabriel S. Dichter, Cara A Damiano, John A. Allen
Journal of Neurodevelopmental Disorders , 2012, DOI: 10.1186/1866-1955-4-19
Combination of valproate and paroxetine in mice exposed to picrotoxin
Kamal SM
International Journal of Nanomedicine , 2012, DOI: http://dx.doi.org/10.2147/IJN.S31050
Abstract: mbination of valproate and paroxetine in mice exposed to picrotoxin Original Research (2615) Total Article Views Authors: Kamal SM Published Date May 2012 Volume 2012:7 Pages 2583 - 2589 DOI: http://dx.doi.org/10.2147/IJN.S31050 Received: 20 February 2012 Accepted: 12 March 2012 Published: 23 May 2012 Sahar M Kamal Department of Pharmacology, Faculty of Medicine, University of Ain-Shams, Cairo, Egypt Abstract: The frequent coexistence of depression in epileptic patients raises the issue of simultaneous use of antidepressants along with antiepileptic drugs in the management of such cases. However, it is necessary to evaluate the safety of these antiepileptic/antidepressant drug combinations. The present study investigates the effect of the antidepressant paroxetine (a selective serotonin reuptake inhibitor) administered alone or in combination with the antiepileptic drug sodium valproate on chemoconvulsions induced by picrotoxin (PTX). Seizure score was recorded in vivo, and the levels of thiobarbituric acid-reactive substances and gamma aminobutyric acid (GABA) were measured in the nucleus accumbens of the tested groups of mice. The results show enhancement of seizure severity with significant reduction in GABA levels upon PTX treatment that were reversed by its combination with sodium valproate. On the other hand, paroxetine administered in combination with sodium valproate provided significant protection against PTX-induced convulsions as well as a significant increase in GABA levels in selected brain areas. These results favor their application in management of epilepsy-depression comorbidities.
The Effect of Oral Ascorbic Acid Pretreatment on Feeding Changes Following Injection in Nucleus Accumbens Shell in Adult Male Rats
Salari S,Abbasnejad M,Badreh F,Esmaeili Mahani S
Tehran University Medical Journal , 2012,
Abstract: Background: Ascorbic acid (AA) is not synthesized in the brain but it is actively transported through blood-brain barrier by SVCT2 cotransporter and it is stored in high concentrations with heterogeneous distribution in areas such as nucleus accumbens shell (AcbSh) in the mammalian brain. Previous studies have shown that Ascorbic acid injection into AcbSh decreases feeding; therefore, in the present study we evaluated the effects of oral Ascorbic acid pretreatment on changes in feeding upon its injection in AcbSh in adult male rats.Methods: Sixty-three adult male rats (220-280 g) were divided into five treatment and five pretreatment groups. The treatment groups included the control (intact) group, sham-operated Ascorbic acid group that received normal saline as vehicle, and three other groups that received different doses of ascorbic acid (10, 50 and 250 μg/rat) by injection into AcbSh for four days. The pretreatment groups received Ascorbic acid (100 mg/kg) for 15 days via gastric gavage before receiving the aforementioned doses in treatment groups into intra nucleus AcbSh. Feeding measurement was repeated every 12 hours by automatic metabolic cage.Results: The results indicated that all injected doses of Ascorbic acid (10, 50 and 250 μg/rat) into nucleus accumbens shell decrease food intake (P<0.05) in rats and oral Ascorbic acid pretreatment had no effects in this regard.Conclusion: Our findings show that ascorbic acid is an effective factor in feeding regulation. Oral pretreatment seems to have no influence on the central effects of ascorbic acid in the nucleus accumbens shell.
Morphine injection in the ventral tegmental area and nucleus accumbens and decreasing anxiety in rat
Vaezi Gh,Zarrindast M r,Salarian A
Tehran University Medical Journal , 2007,
Abstract: Background: Anxiety is a complex phenomenon with important results. In fact anxiety is a biologic process that has repetitive biological and physiological effect on the biological structure of brine. From long time ago anxiety and fear has bean one of the important psychological issues and for the control of anxiety different drugs with different mechanisms have been presented and understanding mechanisms that are involved lead us to newer drugs discovery. In this research the effect of morphine on the anxiety in the adult Male rats in the Ventral Tegmental area (VTA) and Nucleus Accumbens (NAc) was studied.Methods: The elevated plus maze was used in combination with the percentage of time spent in the open arms of the maze (OAT %) and the percentage of entries into the open arms (OAE %) to measure anxiety. Increases in the OAT% and OAE% indicate an anxiolytic effect (reduction in anxiety), whereas decreases in the OAE% and OAT% indicate an anxiogenic effect. Adult male rats, weighing 200-240 grams, underwent surgery. After five days, the rats were injected with saline and three different doses of morphine (2.5, 5, and 7.5 μl/rat). Experiment one included the injections into the VTA. In the second experiment, these injections were in the NAc. Behavioral tests were conducted between 12 pm and 4 pm and each animal was used once for each experiment.Results: In the first experiment, although these doses of morphine injected into the TVA had no effect on the OAE%, a dose of 5μl/rat increased the OAT%, showing a decrease in the animals' anxiety. In the second experiment, doses of 2.5μl/rat injected into the NAc induced a significant increase in the OAT% and OAE%, there by displaying decreased anxiety in the animal. However, no significant change in the activity of the animals was observed.Conclusion: As a Result of these experiments, it seems that different doses of morphine can decrease anxiety, probably through interaction with gabaergic system.
Neurons of human nucleus accumbens
Sazdanovi? Maja,Sazdanovi? Predrag,?ivanovi?-Ma?u?i? Ivana,Jakovljevi? Vladimir
Vojnosanitetski Pregled , 2011, DOI: 10.2298/vsp1108655s
Abstract: Background/Aim. Nucleus accumbens is a part of the ventral striatum also known as a drug active brain region, especially related with drug addiction. The aim of the study was to investigate the Golgi morphology of the nucleus accumbens neurons. Methods. The study was performed on the frontal and sagittal sections of 15 human brains by the Golgi Kopsch method. We classified neurons in the human nucleus accumbens according to their morphology and size into four types: type I - fusiform neurons; type II - fusiform neurons with lateral dendrite, arising from a part of the cell body; type III - pyramidal-like neuron; type IV - multipolar neuron. The medium spiny neurons, which are mostly noted regarding to the drug addictive conditions of the brain, correspond to the type IV - multipolar neurons. Results. Two regions of human nucleus accumbens could be clearly recognized on Nissl and Golgi preparations each containing different predominant neuronal types. Central part of nucleus accumbens, core region, has a low density of impregnated neurons with predominant type III, pyramidal-like neurons, with spines on secondary branches and rare type IV, multipolar neurons. Contrary to the core, peripheral region, shell of nucleus, has a high density of impregnated neurons predominantly contained of type I and type IV - multipolar neurons, which all are rich in spines on secondary and tertiary dendritic branches. Conclusion. Our results indicate great morphological variability of human nucleus accumbens neurons. This requires further investigations and clarifying clinical significance of this important brain region.
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