Research PapersIndividual differences in behavioral responses to novelty and amphetamine self-administration in male and female ratsKlebaur, J.E.a; Bevins, R.A.b; Segar, T.M.c; Bardo, M.T.cAuthor Information a Department of Psychology and Neuroscience Program, University of Michigan, Ann Arbor, Michigan, USA; b Department of Psychology, University of Nebraska-Lincoln, Lincoln, Nebraska, USA; c Department of Psychology, University of Kentucky, Lexington, Kentucky, USA Correspondence to M.T. Bardo, 115 Kastle Hall, Lexington, KY 40506-0044, USA. E-mail: [email protected] Received 21 March 2000 Revised 25 April 2001 Accepted 25 April 2001 Behavioral Pharmacology: July 2001 - Volume 12 - Issue 4 - p 267-275 Buy Abstract Previous work has shown that individual differences in locomotor activity in an inescapable novel environment can predict acquisition of amphetamine self-administration. The current study examined whether individual differences in approach to novelty in a free choice test could also predict amphetamine self-administration. Further, the current study examined whether individual differences in either free choice or inescapable novelty tests could predict responding for a nondrug reinforcer (sucrose) in the presence and absence of amphetamine. Male and female rats were first tested for their response to free choice novelty (playground maze and novelty-induced place preference tests) and inescapable novelty. They were then tested for acquisition of sucrose-reinforced responding, amphetamine-induced changes in maintenance of sucrose-reinforced responding, and amphetamine self-administration. Based on the inescapable novelty test, acquisition of sucrose-reinforced responding was more rapid in male high responders (HR) compared to low responders (LR). This effect in males did not generalize to females. None of the novelty tests predicted the ability of amphetamine to decrease sucrose-maintained responding. However, using the inescapable novelty test, both male and female HRs self-administered more amphetamine than LRs within the dose range tested (0.03–0.16 mg/kg/infusion). Neither the playground maze nor the novelty-induced place preference test predicted amphetamine self-administration. These results indicate that responses to free choice novelty and inescapable novelty predict different components of amphetamine-induced behavior. © 2001 Lippincott Williams & Wilkins, Inc.