Distinct effects of enriched environment on dopamine clearance in nucleus accumbens shell and core following systemic nicotine administration

Abstract

Environmental enrichment during development may reduce drug abuse liability by modulating dopamine transporter (DAT) function. Nucleus accumbens (NAc) shell and core respond differentially to regulate the rewarding properties and locomotor stimulant effects of psychostimulants. The current study evaluated dopamine (DA) clearance (CL(DA) ) in the NAc shell and core using in vivo voltammetry in rats raised in an enriched condition (EC) or an impoverished condition (IC) and determined the effect of nicotine (0.4 mg/kg) on CL(DA) . Baseline CL(DA) in NAc shell and core was not different between EC and IC rats. In the saline control group, CL(DA) in NAc shell was greater across time in IC when compared with EC rats, whereas CL(DA) in NAc core was greater in EC rats when compared with IC rats. Consistent with these findings, opposite effects of enrichment on DA clearance in shell and core were obtained following acute nicotine administration. In NAc shell, nicotine increased CL(DA) in EC rats, but not in IC rats. Conversely, in NAc core, nicotine increased CL(DA) in IC rats, but not in EC rats. The current results demonstrate that environmental enrichment differentially regulates the response to nicotine in NAc shell and core via alterations in DAT function, which may explain how environmental enrichment reduces the behavioral response to nicotine.