Serotonin and Alcohol Consumption

The involvement of serotonin (5-HT) in alcohol consumption was studied in lines of rats selectively bred for disparate alcohol drinking behavior. Neurochemical data indicated that the alcohol-preferring (P) line and the high alcohol-drinking (HAD) line had lower CNS levels of 5-HT and/or 5-hydroxyindoleacetic acid compared with their respective counterparts, the alcohol-nonpreferring (NP) and low alcohol-drinking (LAD) rats. In addition, higher densities of cortical 5-HTlA receptors were found in the P compared with the NP rats. Pharmacological studies indicated that agents which increase the actions of 5-HT or mimic its effects at 5-HT1 5-HT2 receptors can decrease the alcohol intake of P and HAD rats. Overall, the data suggest that (a) innate abnormalities exist in 5-HT systems in the CNS of P and HAD rats which may be associated with their high alcohol intake and (b) multiple 5-HT receptor subtypes might be involved in regulating alcohol consumption.