Authors: Mary E Cain C Matthew Smith Michael T Bardo
Publish Date: 2004/05/07
Volume: 176, Issue: 2, Pages: 129-138
Abstract
Rats categorized as high responders HR based on their activity in an inescapable novel environment selfadminister more amphetamine than low responder LR rats Previous research has also demonstrated that novel stimuli presented during the amphetamine selfadministration session decreases the number of infusions earnedThis study determined whether individual differences in response to inescapable or freechoice novelty differentially predict the ability of novel stimuli to decrease amphetamine selfadministration Further this study determined whether novel stimuli maintained the ability to reduce selfadministration with repeated presentations and whether the effect of novel stimuli varied as a function of the unit dose of amphetamine testedMale rats were screened for their response in inescapable and freechoice novelty tests Following initial training using a high unit dose of amphetamine 01 mg/kg per infusion the dose was reduced 003 mg/kg per infusion and novel stimuli were presented in the operant conditioning chamber on four separate sessions In experiment 2 novel stimuli were presented during several sessions at a variety of amphetamine doses 0003 001 003 and 0056 mg/kg per infusionFour repeated presentations of novel stimuli reduced amphetamine selfadministration with no significant loss in the effect of novel stimuli across repeated presentations In experiment 2 novel stimuli reduced amphetamine selfadministration at low unit doses 0003 mg/kg and 001 mg/kg per infusion and rats classified as HR based on their activity in inescapable novel stimuli were more disrupted by novel stimuli than LR ratsResearch was funded by USPHS grant P50 DA05312 MEC was supported by USPHS grant F32 DA16013 CMS was supported by Summer Research and Creativity Grant at the University of Kentucky The authors would like to thank Justin Dixon William Dotson and Nathan Gilbertson for their assistance with this project
Keywords: