title: Nicotine-induced conditioned taste aversions are enhanced in rats with lesions of the area postrema.
abstract: Lesions, which destroy the area postrema and damage the adjacent nucleus of the solitary tract, attenuate or abolish conditioned taste aversions (CTA) induced by a variety of pharmacological agents. In the present experiment 2 groups of male rats received lesions of the area postrema and 2 groups were given sham lesions. One lesioned group and one sham-lesioned group were twice conditioned with 30-min access to a novel 0.15% saccharin solution followed by injection of nicotine (1 mg/kg, IP). The other 2 groups were similarly conditioned with saccharin followed by saline injections. In subsequent two-bottle choice tests (saccharin vs. water), the saline-injected rats exhibited strong preferences for saccharin, the sham-lesioned rats injected with nicotine showed a weak but significant (p less than 0.05) aversion to saccharin, and the area postrema-lesioned rats injected with nicotine displayed a significantly (p less than 0.05) stronger CTA than the drug-injected sham-lesioned animals. In Phase 2 all rats were given novel chocolate metrecal (30 min) followed by injection of scopolamine HCl (1 mg/kg, IP). The area postrema-lesioned rats showed significant (p less than 0.01) preference for the chocolate taste relative to the aversions shown by the sham-lesioned animals. Thus, area postrema lesions attenuated a scopolamine-induced CTA, but enhanced a nicotine-induced aversion. These results suggest that nicotine and scopolamine act at different neural sites in producing CTAs.
authors.affiliation: Department of Psychology, University of Western Ontario, London, Canada.
authors.forename: K P
authors.initials: KP
authors.lastname: Ossenkopp
authors.forename: L
authors.initials: L
authors.lastname: Giugno
mesh_terms: D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects*; D001933:Brain Stem / Q000502:physiology*; D003213:Conditioning, Psychological / Q000187:drug effects*; D008297:Male; D009538:Nicotine / Q000494:pharmacology*; D051381:Rats; D012439:Saccharin; D012601:Scopolamine / Q000494:pharmacology; D013649:Taste / Q000187:drug effects*
chemical_list: D009538:Nicotine; D012601:Scopolamine; D012439:Saccharin