Amphetamine locomotor sensitization and conditioned place preference in adolescent male and female rats neonatally treated with quinpirole

摘要

Neonatal quinpirole treatment has been shown to produce an increase of dopamine D2 - like receptor sensitivity that persists throughout the animal's lifetime. The objective was to analyze the effects of neonatal quinpirole treatment on effects of amphetamine in adolescent rats using locomotor sensitization and conditioned place preference (CPP) procedures. Sprague-Dawley rats were treated with quinpirole (1mg/kg) or saline from postnatal days (P)1-11 and raised to adolescence. For locomotor sensitization, animals were given amphetamine (1mg/kg) or saline every second day from P35-47 and placed into a locomotor arena. In females, neonatal quinpirole treatment enhanced amphetamine locomotor sensitization compared to quinpirole-free controls sensitized to amphetamine. Males demonstrated sensitization to amphetamine, but this was muted compared to females and unaffected by neonatal quinpirole. For CPP, animals were conditioned for eight consecutive days (P32-39) with amphetamine (1mg/kg) or saline and a drug-free preference test was performed at P40. Neonatal quinpirole enhanced time spent in the amphetamine-paired context compared to quinpirole-free controls conditioned with amphetamine, but only female controls conditioned with amphetamine spent more time in the drug-paired context compared to saline-treated controls. Increased D2 -like receptor sensitivity appears to have enhanced the behavioral effects of amphetamine, but these effects were more prevalent in adolescent females compared to males.