MODULATION OF 5-HT(1C) RECEPTORS AND PHOSPHOINOSITIDE SYSTEM BY ETHANOL-CONSUMPTION IN RAT-BRAIN AND CHOROID-PLEXUS

The effect of chronic ethanol consumption (60 days) on 5-HT1C receptor s as measured by [H-3]mesulergine binding in the hippocampus, cortex, and choroid plexus of rats was investigated. The 5-HT1c receptor-media ted phosphoinositide hydrolysis in rat choroid plexus was also investi gated. It was observed that chronic ethanol treatment significantly in creased the 5-HT-stimulated [H-3]inositol 1-phosphate ([H-3]IP1) forma tion, as well as the density (B(max)) of 5-HT1c receptors without caus ing a significant change in affinity (K(D)) of [H-3]mesulergine bindin g in rat choroid plexus. It was also observed that chronic ethanol con sumption had no significant effect on the B(max) or K(D) of 5-HT1c rec eptor binding sites in the hippocampus and cortex brain regions of rat s. These results thus suggest that chronic ethanol consumption causes an up-regulation of both 5-HT1C receptors and 5-HT1c receptor-mediated phosphoinositide hydrolysis in rat choroid plexus but has no signific ant effects on the 5-HT1c receptors in brain. These results also sugge st that 5-HT1c receptors and their functional response may be involved in the pathogenesis of alcohol dependence.