NMDA receptors in the basolateral amygdala mediate acquisition and extinction of an amphetamine conditioned place preference.

Abstract

Previous work from our laboratory has indicated that temporary inactivation of the basolateral amygdala (BLA) with bupivacaine blocks acquisition, consolidation, and retrieval of an amphetamine conditioned place preference (CPP). The present study was designed to extend this line of investigation by examining whether N-methyl-D-aspartate (NMDA) receptors in the BLA mediate acquisition and extinction of an amphetamine CPP. Adult male Long-Evans rats received bilateral intra-BLA injections of the NMDA receptor antagonist 2-amino-5-phosphonopentanoic acid (AP5; 1.25 μg, 2.5 μg, or 5.0 μg) or saline prior to each session of CPP acquisition (Experiment 1). In addition, separate groups of rats received intra-BLA injections of the sodium channel blocker bupivacaine (Experiment 2), AP5 (1.25 μg, 2.5 μg, or 5.0 μg; Experiment 3), or saline prior to each session of CPP extinction training. Results indicated that intra-BLA injection of bupivacaine or AP5 (2.5 or 5.0 μg) disrupted acquisition of an amphetamine CPP. In addition, neural inactivation of the BLA with bupivacaine blocked extinction of CPP. Finally, intra-BLA AP5 injections (2.5 or 5.0 μg) were sufficient to block CPP extinction. The present findings indicate that NMDA receptor activity in the BLA is critical for acquisition and extinction of an amphetamine CPP and may be relevant to understanding the neural mechanisms underlying some aspects of drug seeking and addiction. (PsycINFO Database Record (c) 2019 APA, all rights reserved).