5-HT3 receptor antagonist, tropisetron, does not influence ethanol-induced conditioned taste aversion and conditioned place aversion

Numerous works have demonstrated an interaction between 5-HT3 receptor antagonists and some of the effects of ethanol (EtOH) using biochemical, electrophysiological, and behavioral techniques. Thus, 5-HT3 antagonists are capable of reducing EtOH-induced release of dopamine in the nucleus accumbens, EtOH-induced hyperlocomotion, and voluntary EtOH consumption in laboratory animals. In addition to its rewarding effect, EtOH possesses aversive properties as demonstrated in the conditioned taste aversion (CTA) and conditioned place aversion (CPA) paradigms. The role of 5-HT3 receptors in aversive effects of EtOH remains, however, unknown. We decided to study the effect of 5-HT3 antagonist, tropisetron, on aversive properties of EtOH (1.5 g/kg IP) in rats using the CTA and CPA models. In addition, effect of tropisetron on morphine (Mf)-induced CTA (10.0 mg/kg SC) was investigated. Tropisetron (0.001-0.5 mg/kg) did not influence CTA produced by EtOH and Mf. When given alone, it failed to produce any taste conditioning. Furthermore, tropisetron did not modify CPA induced by EtOH. Our results suggest that 5-HT3 receptors are not involved in aversive effects of acute doses of EtOH. Copyright (C) 1997 Elsevier Science Inc.