Cocaine self-administration in rats influenced by environmental conditions: implications for the etiology of drug abuse

The data suggest that environmental factors play a major role in determining individual differences in the propensity to self-administer cocaine and that, as such, they should be considered more seriously by those interested in the basis and treatment of drug abuse.

Abstract

The present study investigated the possibility of environmental factors as an explanation for between-subject differences in cocaine self-administration. Weaning rats (21 days) were housed in isolated or aggregated conditions for 6 weeks and were tested for intravenous cocaine self-administration (0.1-1.0 mg/kg/infusion). Rats housed in groups failed to reliably self-administer this drug whereas isolated rats readily acquired an operant to receive infusions of cocaine. These data suggest that environmental factors play a major role in determining individual differences in the propensity to self-administer cocaine and that, as such, they should be considered more seriously by those interested in the basis and treatment of drug abuse.