Influence of housing conditions on the acquisition of intravenous heroin and cocaine self-administration in rats.
Group-housed and individually housed rats were tested for the acquisition of a lever-pressing response reinforced by intravenous heroin or cocaine; animals in each housing condition quickly learned to self-administer drug. In the first experiment the isolated rats learned to self-administer heroin earlier than the group-housed animals, but the two groups self-administered similar levels of heroin by the fifth week of testing. In the second experiment cocaine self-administration was learned with equal speed in the two groups, and similar levels of cocaine were self-administered by both groups throughout the experiment. These data indicate that while social isolation can influence levels of heroin self-administration, isolation is not a necessary condition for heroin or heroin or cocaine injections to be reinforcing.
Bozarth
M A
MA
Department of Psychology, Concordia University, Montréal, P.Q., Canada.
Murray
A
A
Wise
R A
RA
D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D003042:Cocaine / Q000008:administration & dosage*; D003932:Heroin / Q000008:administration & dosage*; D006799:Housing, Animal; D007275:Injections, Intravenous; D008297:Male; D051381:Rats; D012646:Self Administration; D012934:Social Isolation / Q000523:psychology*; D019966:Substance-Related Disorders / Q000503:physiopathology*
D003932:Heroin; D003042:Cocaine