title: The effects of the 5-HT3 receptor antagonist tropisetron on cocaine-induced conditioned taste aversions.
abstract: Although cocaine readily induces taste aversions, little is known about the mechanisms underlying this effect. Recent work has shown that cocaine's actions on serotonin (5-HT) may be involved. To address this possibility, the present experiments examined a role of the specific 5-HT receptor, 5-HT3, in this effect given that it is implicated in a variety of behavioral effects of cocaine. This series of investigations first assessed the aversive effects of the 5-HT3 receptor antagonist tropisetron alone (Experiment 1). Specifically, in Experiment 1 male Sprague-Dawley rats were given repeated pairings of a novel saccharin solution and tropisetron (0, 0.056, 0.18 and 0.56mg/kg). Following this, a non-aversion-inducing dose of tropisetron (0.18mg/kg) was assessed for its ability to block aversions induced by a range of doses of cocaine (Experiment 2). Specifically, in Experiment 2 animals were given access to a novel saccharin solution and then injected with tropisetron (0 or 0.18mg/kg) followed by an injection of various doses of cocaine (0, 10, 18 and 32mg/kg). Cocaine induced dose-dependent taste aversions that were not blocked by tropisetron, suggesting that cocaine's aversive effects are not mediated by 5-HT, at least at this specific receptor subtype. At the intermediate dose of cocaine, aversions appeared to be potentiated, suggesting 5-HT3 may play a limiting role in cocaine's aversive effects. These data are discussed in the context of previous examinations of the roles of serotonin, dopamine, and norepinephrine in cocaine-induced aversions.
authors: Psychopharmacology Laboratory, Department of Psychology, American University, Washington, DC 20016, United States. mariabriscione@gmail.com
authors: Maria A
authors: MA
authors: Briscione
authors: Katherine M
authors: KM
authors: Serafine
authors: Andrew P
authors: AP
authors: Merluzzi
authors: Kenner C
authors: KC
authors: Rice
authors: Anthony L
authors: AL
authors: Riley
mesh_terms: D000818:Animals; D001362:Avoidance Learning; D003216:Conditioning, Operant; D007211:Indoles / Q000494:pharmacology*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D044406:Receptors, Serotonin, 5-HT3 / Q000187:drug effects*; D013649:Taste / Q000187:drug effects*; D000077526:Tropisetron
chemical_list: D007211:Indoles; D044406:Receptors, Serotonin, 5-HT3; D000077526:Tropisetron