EFFECTS OF FOOD-DEPRIVATION ON CONDITIONED TASTE-AVERSIONS IN RATS

Food deprivation increases the rewarding effects of self-administered drugs such as psychomotor stimulants and benzodiazepines. These drugs also possess aversive properties and can produce conditioned tast aver sions (CTA). Because drug-seeking behavior is most likely affected by both the rewarding and aversive properties of drugs, we hypothesize th at food deprivation might also attenuate a drug's aversive consequence s. The CTAs induced by three different drugs (amphetamine, chlordiazep oxide, and LiCl) were assessed separately. Male Long-Evans rats were a ssigned to one of two feeding conditions: restricted (maintained at 80 % of free-feeding body weight), or nonrestricted (with ad lib food). B oth groups received CTA training, consisting of an intraoral infusion of a novel saccharin solution (10 min) followed immediately by one of two IP injections: paired rats received drug, and unpaired rats receiv ed a similar volume of saline. After 10 days of ad lib food access, sa ccharin was presented to all rats again, and the latency to reject the tastant was used as an index of CTA learning. The rats that had been food restricted at the time of conditioning exhibited attenuated CTAs relative to those that had not been deprived. These differences were s een only when a rewarding drug (amphetamine or chlordiazepoxide) and n ot when a nonrewarding drug (LiCl) was used as the unconditioned stimu lus. In a separate experiment, we established that this effect is appa rent only when the deprivation period precedes conditioning rather tha n precedes testing. The present results indicate that food deprivation modulates the acquisition of a CTA induced by amphetamine or chlordia zepoxide, but not LiCl. (C) 1998 Elsevier Science Inc.