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The electrochemical sensor for Dopamine (DA) was investigated using poly(amido black) modified carbon paste electrode (MCPE) by the cyclic voltammetric (CV) technique. The film-coated electrode exposed supreme electrocatalytic properties towards electrochemical detection DA and uric acid (UA). The limit of detection (LOD) of DA and UA found to be 2.03 µM and 3.6 µM respectively. Furthermore effectively selective separation of DA and UA in a binary mixture was accomplished. The application of the developed electrode was demonstrated by detecting DA in the injection sample with adequate recoveries. The sensor was stable, sensitive, selective and reproducible.

Changes in chromatin conformation and nonhistone nuclear protein composition were analyzed in various classes of nuclei from the brain of control and chronic ethanol fed rats. Conformational studies of chromatin by circular dichroism spectrophotometry showed an increased molar ellipticity [theta] of chromatin in neuronal, astrocyte and oligodendroglial nuclei due to ethanol treatment. The increased molar ellipticity directly indicates relaxed state of chromatin in these nuclei, which facilitates ready state of transcription and replication. Further, the circular dichroism spectrum, due to a change over point at approximately 260 nm also indicated the possibility of DNA-protein interactions governing chromatin conformation. In microglial nuclei, the circular dichroism spectrum showed a decrease in molar ellipticity due to ethanol treatment, indicating the existence of chromatin in a condensed state. This type of circular dichroism change points towards the possibility of closed conformation, which renders the gene sequences not accessible due to conformational constrains of the chromatin. Since circular dichroism changes indicated the involvement of DNA-protein interactions, changes in nonhistone nuclear proteins were analyzed in these classes of nuclei by two-dimensional gel electrophoresis. In astrocytes and oligodendrocytes two new proteins appeared in each type of nuclei while in neurons and microglial nuclei four different proteins were either completely missing or showed a decrease. These changes indicate the presence of dynamic flux of nonhistone nuclear proteins in chromatin. Taken together, the changes in chromatin conformation, associated with specific changes in non histone nuclear protein composition suggest the modulation of chromatin as a response to ethanol evoked stimulus and has relevance in the regulation of cellular responses to ethanol crisis in brain.

The effect of combined administration of ethanol and manganese on the brain tissue of rats was investigated to evaluate the role of alcohol ingestion in inducing susceptibility to manganese poisoning. Ethanol and manganese alone and the combination of the two were administered orally daily to the rats for 30 days. Almost identical increase in the brain contents of manganese in rats receiving the metal alone and in combination with ethanol indicates that ethanol administration does not influence the accumulation of manganese in that organ. The copper contents of brain also increased to almost the same extent in these two groups. Synergistic effect of ethanol and manganese was noticed on increasing the activity of ATPase and RNase while marked antagonistic effect was observed on the activity of MAO. The mechanism and the significance of these neurochemical alterations occurring after the administration of ethanol and manganese have been discussed.

Concentrations of corticosterone in brain areas of TO strain mice were measured by radioimmunoassay. The studies examined the effects of routine laboratory maneuvers, variation during the circadian peak, adrenalectomy, social defeat and acute injections of alcohol on these concentrations. Brief handling of mice increased corticosterone levels in plasma but not in striatum and reduced those in the hippocampus. Single injections of isotonic saline raised the plasma concentrations to a similar extent as the handling, but markedly elevated concentrations in the three brain regions. Five minutes exposure to a novel environment increased hippocampal and cerebral cortical corticosterone levels and striatal concentrations showed a larger rise. However, by 30 min in the novel environment, plasma concentrations rose further while those in striatum and cerebral cortex fell to control levels and hippocampal corticosterone remained elevated. Over the period of the circadian peak the hippocampal and striatal concentrations paralleled the plasma concentrations but cerebral cortical concentrations showed only small changes. Adrenalectomy reduced plasma corticosterone concentrations to below detectable levels after 48 h but corticosterone levels were only partially reduced in the hippocampus and striatum and remained unchanged in the cerebral cortex. Single or repeated social defeat increased both brain and plasma concentrations after 1 h. Acute injections of alcohol raised the regional brain levels in parallel with plasma concentrations. The results show that measurements of plasma concentrations do not necessarily reflect the levels in brain. The data also demonstrate that corticosterone levels can change differentially in specific brain regions. These results, and the residual hormone seen in the brain after adrenalectomy, are suggestive evidence for a local origin of central corticosterone.

Administration of low amounts of ethanol for a prolonged period increases rat brain synaptosomal (Na+-K+)-ATPase activity, the increase being less in the protein deficient rats. The adaptive mechanism to offset the stress imposed by the continued presence of ethanol seems to be depressed by low plane of nutrition. In vivo and in vitro effects of ethanol on (Na+-K+)ATPase seems to be different.

Glutathione (GSH) and other non-protein sulfhydryls (NPS) are known to protect cells from oxidative stress and from potentially toxic electrophiles formed by biotransformation of xenobiotics. This study examined the effect of a simultaneous administration of styrene and ethanol on NPS content and lipid peroxidation in rat liver and brain. Hepatic cytochrome P450 and cytochrome b5 content, aniline hydroxylase and aminopyrine N-demethylase activities as well as the two major urinary metabolites of styrene, mandelic and phenylglyoxylic acids were also measured. Groups of rats given ethanol for 3 weeks in a liquid diet were exposed, starting from the second week, to 326 ppm of styrene (6 h daily, 5 days a week, for 2 weeks). In control pair-fed animals, styrene produced about 30% depletion of brain NPS and 50% depletion of hepatic NPS. Subchronic ethanol treatment did not affect hepatic NPS levels, but caused 23% depletion of brain NPS. Concomitant administration of ethanol and styrene caused a NPS depletion in brain tissue in the order of 60%. These results suggest that in the rat, simultaneous exposure to ethanol and styrene may lead to considerable depletion of brain NPS. This effect is seen when both compounds are given on a subchronic basis, a situation which better resembles possible human exposure.

 While the molecular entity responsible for the rewarding effects of virtually all drugs of abuse is known, that for ethanol remains uncertain. Some lines of evidence suggest that the rewarding effects of alcohol are mediated not by ethanol per se but by acetaldehyde generated by catalase in the brain. However, the lack of specific inhibitors of catalase has not allowed strong conclusions to be drawn about its role on the rewarding properties of ethanol. The present studies determined the effect on voluntary alcohol consumption of two gene vectors, one designed to inhibit catalase synthesis and one designed to synthesize alcohol dehydrogenase (ADH), to respectively inhibit or increase brain acetaldehyde synthesis. The lentiviral vectors, which incorporate the genes they carry into the cell genome, were (i) one encoding a shRNA anticatalase synthesis and (ii) one encoding alcohol dehydrogenase (rADH1). These were stereotaxically microinjected into the brain ventral tegmental area (VTA) of Wistar-derived rats bred for generations for their high alcohol preference (UChB), which were allowed access to an ethanol solution and water. Microinjection into the VTA of the lentiviral vector encoding the anticatalase shRNA virtually abolished (-94% p < 0.001) the voluntary consumption of alcohol by the rats. Conversely, injection into the VTA of the lentiviral vector coding for ADH greatly stimulated (2 to 3 fold p < 0.001) their voluntary ethanol consumption.The study strongly suggests that to generate reward and reinforcement, ethanol must be metabolized into acetaldehyde in the brain. Data suggest novel targets for interventions aimed at reducing chronic alcohol intake.

Experimental evidence indicates a potential role of 5-HT6 receptors in the regulation of addictive behavior. We studied the effects of a potent and selective 5-HT6 receptor antagonist (compound A) on voluntary ethanol intake and behavioral/neurochemical changes induced by ethanol. The pharmacokinetic interaction of compound A and ethanol was assessed. The effect of compound A on schedule-induced ethanol polydipsia was studied to determine its effect on voluntary ethanol intake. Open-field and ethanol-induced loss of righting reflex assays were carried out to determine the effect of compound A on the ataxic and sedative effects of ethanol. The effect on motor learning was evaluated using rotarod and brain microdialysis was carried out to study the effect on monoaminergic neurotransmission. No significant changes were observed in the pharmacokinetic parameters of compound A when cotreated with ethanol. Compound A significantly decreased voluntary ethanol consumption and attenuated the effects of ethanol on motor learning. Compound A also antagonized the sedative and ataxic effects of ethanol. The effect of ethanol on the dopaminergic and noradrenergic neurotransmission was blocked by compound A. The effects of compound A were evident only after chronic treatment. Compound A may have attenuated the behavioral effects of ethanol by blocking the ethanol-induced efflux of dopamine and norepinephrine in the motor cortex.