Drug exposure and the acquisition and retention of a conditioned taste aversion

Two experiments, the 1st with 24 female and the 2nd with 18 male Long-Evans rats, examined the effects of pre- and postexposure to a drug on the acquisition and retention of a conditioned taste aversion induced by that drug. Exp I demonstrated that although drug preexposure attenuated a subsequent conditioned aversion, repeated taste-drug pairings reversed the initial attenuation effect and resulted in nearly complete avoidance of consumption. Exp II, however, demonstrated that drug postexposure did not alter a previously established conditioned aversion, although the postexposure experiences were effective in attenuating a conditioned aversion to a 2nd novel solution. It is suggested that conditioned aversions are mediated by ACTH and that preexposure to a drug results in tolerance to that drug, yielding a smaller ACTH response and thereby a weaker aversion. (29 ref) (PsycINFO Database Record (c) 2006 APA, all rights reserved).