Individual differences in novelty seeking on the playground maze predict amphetamine conditioned place preference

Previous research has shown that a rat's level of activity in a novel envir onment can predict the strength of amphetamine-induced locomotor behavior a nd self-administration, but not amphetamine-conditioned place preference. T he increase in activity observed when a rat is exposed to an inescapable no vel environment may reflect escape behavior due to stress. To assess approa ch to novelty in a free-choice test, we examined the ability of a new test, the playground maze, to predict individual differences in response to amph etamine (1 or 3 mg/kg). Using the playground maze to categorize rats as eit her high or low novelty seekers, it was found that individual differences i n novelty seeking did not predict amphetamine-induced changes in locomotor activity following either a single or repeated injections. However, high no velty seekers showed greater amphetamine-conditioned place preference than low novelty seekers. These results provide support for the hypothesis that novelty seeking and drug reward are neuropharmacologically related. (C) 199 9 Elsevier Science Inc.