Effects of 5-HT3 receptor agonists on voluntary ethanol intake in rats maintained on a limited access procedure

Recent evidence from a variety of laboratory studies suggests that the central effects of ethanol (EtOH) are mediated by serotonin 5-HT3 receptors. Notably, EtOH is able to potentiate 5-HT action on 5-HT3 ionophore, and 5-HT3 antagonists are known to reduce certain effects of EtOH. In the present study, we evaluated the effects of two agonists of 5-HT3 receptors, 2-methyl-5-HT (2-Me-5-HT) and m-chlorophenylbiguanide (m-CPBG) that were microinjected i.c.v. and into the nucleus accumbens (NAC) on EtOH intake in Wistar rats with high EtOH preference. 2-Me-5-HT given i.c.v. (1 and 10 microg per rat) and into the NAC (bilaterally 1 and 10 microg per site) significantly reduced EtOH intake in the limited access paradigm (2h session). On the other hand m-CPBG was inactive after intra-NAC administration. It is concluded that central 5-HT3 receptors are involved in the regulation of EtOH consumption.