No abstract

The rate of alcohol elimination is significantly associated with the ADH2 genotype of Jewish males. Evidence for variation in alcohol metabolism across ADH genotypic groups provides support for the role of physiologic protective factors in alcohol drinking and suggests that reduced drinking among Jews may be genetically as well as environmentally determined. We believe that application of the novel "Indiana clamp" enhances AER measurement accuracy, allowing for detection of hitherto undetectable differences.

The effect of blocking the A subtype of gamma-aminobutyric acid (GABA(A)) receptors in the anterior ventral tegmental area (VTA) on ethanol (EtOH; 10% v/v) and saccharin (SACC; 0.0125%) consumption was investigated in alcohol-preferring P rats. Picrotoxin (0.005, 0.01, 0.05 and 0.10 microg/0.5 microl) was injected into the VTA, and consumption of EtOH and SACC was assessed in two 2-h limited-access drinking paradigms (concurrent EtOH/SACC access, and alternate-day-access to EtOH and SACC). Under concurrent-access conditions, the picrotoxin microinjections resulted in a 55 and 84% decrease in EtOH consumption at the 0.05 and 0.10 microg doses, respectively, compared with consumption following microinjections of vehicle solution (P<0.05). Saccharin intake was not significantly altered by picrotoxin. Under alternate-day-access drinking conditions, the picrotoxin microinjections resulted in dose-dependent decreases in EtOH consumption of 37-68%, with significant decreases following the 0.005, 0.05 and 0.10 microg doses (P<0.04). Saccharin intake was significantly reduced only at the 0.05 microg dose. The decrease in EtOH consumption after 0.10 microg picrotoxin was attenuated by co-administration of 0.01 microg muscimol. This dose of muscimol had no effect on EtOH consumption when injected alone. Intra-VTA injections of bicuculline (0.04 microg), another GABA(A) antagonist, reduced EtOH intake, comparable to the reduction following 0.10 microg picrotoxin. Microinjections of 0.10 microg picrotoxin in regions outside the VTA failed to decrease EtOH intake. These results suggest that anterior VTA mechanisms regulating alcohol drinking behavior are under tonic GABA inhibition, mediated by GABA(A) receptors. The results also suggest that different neural mechanisms are regulating voluntary EtOH and SACC drinking behaviors.

Puerarin, daidzin, and daidzein are 3 major isoflavonoid compounds isolated from Pueraria lobata, an edible vine used widely in China for various medicinal purposes. We studied the antiinebriation and the antidipsotropic effects of these antioxidants in rats. Daidzin and daidzein shortened alcohol-induced sleep time (loss of righting reflex) in rats that were given ethanol intragastrically but not in those given ethanol intraperitoneally. When daidzin was given to animals intragastrically with the ethanol solution, the blood alcohol concentration (BAC) was found to peak later and be lower than in control rats that were given only the ethanol solution. BACs also receded more slowly if daidzin was fed to the animals. None of the 3 isoflavonoid compounds administered orally affected liver alcohol dehydrogenase or aldehyde dehydrogenase activities, as was reported for intraperitoneal administration. Further experiments indicated that the suppression of the BAC by daidzin was due mainly to delay of stomach emptying. All 3 compounds suppressed voluntary alcohol consumption in alcohol-preferring rats. The decrease in alcohol consumption was accompanied by an increase in water intake, so that the total volume of liquid consumed daily remained unchanged. Daily food consumption and body weight gain were not affected. Alcohol preference returned to baseline levels after the isoflavonoids were discontinued. We postulate that the suppression of alcohol reinforcement produced by these compounds is mediated centrally in the brain reward pathway.