Article date: 1990/1/29
PubMed ID: 2337788
Journal name: Brain research (ISSN: 0006-8993)
The hypothesis that the ventral pallidum is an important site mediating psychomotor stimulant and opiate reinforcement was tested in rats trained to self-administer i.v. cocaine or heroin. Ibotenic acid lesions of the ventral pallidum produced significant decreases in cocaine and heroin self-administration behavior maintained on a fixed-ratio 5 schedule of reinforcement, suggesting an attenuation of the reinforcing value of cocaine and heroin. On a progressive-ratio schedule, ventral pallidal lesions produced significant decreases in the highest ratio obtained in rats self-administering cocaine. Similar results were observed with heroin in a progressive-ratio procedure modified to produce higher levels of responding; lesions of the ventral pallidum produced a significant decrease in the highest ratio obtained. Further, the i.v. co-administration of naloxone and heroin produced a decrease in progressive-ratio responding relative to heroin alone using the modified progressive-ratio schedule. These results suggest that the ventral pallidum is an important site mediating the reinforcing effects of cocaine and heroin and that the nucleus accumbens-ventral pallidum circuit may be a common pathway for both stimulant and opiate reinforcement.
Author List: Hubner C B, Koob G F
Publication Types: Journal Article; Research Support, U.S. Gov't, P.H.S.
Substances mentioned in the article: Heroin; Cocaine;
Mesh terms: Animals; Behavior, Animal/physiology; Cocaine/administration & dosage; Globus Pallidus/drug effects; Heroin/administration & dosage; Male; Rats; Rats, Inbred Strains; Reinforcement Schedule; Self Administration;