Effects of mesolimbic dopamine depletion on responding maintained by cocaine and food

J Exp Anal Behav. 1994 Mar;61(2):213-21. doi: 10.1901/jeab.1994.61-213.


The hypothesis that mesolimbic dopamine is selectively involved in cocaine reinforcement was investigated in the rat. Animals were trained under a multiple schedule in which responding was reinforced by intravenous cocaine (0.75 mg/kg/injection) or food (45-mg pellets) under fixed-ratio 15 schedule requirements in alternate 30-min components of a 2-hr daily session. Infusion of the catecholaminergic neurotoxin 6-hydroxydopamine, but not the vehicle solution, into the region of the nucleus accumbens and olfactory tubercle produced selective reductions in cocaine self-administration without significantly altering responding maintained by food within the same sessions. This effect was reproduced in intact animals by substituting saline for cocaine in the self-administration component. These results support the hypothesis that the reinforcing effects of cocaine are dependent upon mesolimbic dopamine and demonstrate that cocaine self-administration can be disrupted in animals without altering behavior maintained by a nondrug reinforcer.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Cocaine / administration & dosage*
  • Cocaine / metabolism*
  • Dopamine Antagonists*
  • Eating*
  • Nucleus Accumbens / drug effects
  • Oxidopamine / pharmacology*
  • Rats
  • Reinforcement Schedule
  • Reinforcement, Psychology
  • Self Administration


  • Dopamine Antagonists
  • Oxidopamine
  • Cocaine