Conditioned fear stimuli reinstate cocaine-induced conditioned place preference

These studies examined the ability of a conditioned stimulus previously pai red with footshock to reinstate cocaine-induced conditioned place preferenc e. Male rats were given either odor or tone in a paired (PRD group) or expl icitly unpaired (random, RND group) manner with footshock. All rats were su bsequently trained in a cocaine conditioned place preference (CPP) task. Co caine CPP was demonstrated in all groups. After CPP extinction, presentatio n of the conditioned fear stimulus produced a greater degree of reinstateme nt in PRD rats compared to the RIND group. This was true whether the condit ioned stimulus was odor or tone but when odor was used as the conditioned s timulus, the RIND group also partially reinstated cocaine CPP. In rats trai ned with tone as the conditioned stimulus, presentation of the tone during the test for reinstatement produced robust reinstatement of cocaine CPP onl y in the PRD, but not RIND, group. In contrast, a subsequent priming inject ion with cocaine reinstated cocaine CPP equally in both RND and PRD groups. These studies indicate for the first time that conditioned fear stimuli in duce reinstatement of cocaine CPP, and suggest that stimuli associated with prior stress may produce relapse in humans. (C) 2001 Published by Elsevier Science B.V.