Assessment of the relative reinforcing strength of cocaine in socially housed monkeys using a choice procedure.

Czoty, P. W., McCabe, C. ORCID: https://orcid.org/0000-0001-8704-3473 and Nader, M. A. (2005) Assessment of the relative reinforcing strength of cocaine in socially housed monkeys using a choice procedure. Journal of Pharmacology and Experimental Therapeutics, 312 (1). pp. 96-102. ISSN 0022-3565 doi: 10.1124/jpet.104.073411

Abstract/Summary

Position in the social hierarchy can influence brain dopamine function and cocaine reinforcement in nonhuman primates during early cocaine exposure. With prolonged exposure, however, initial differences in rates of cocaine self-administration between dominant and subordinate monkeys dissipate. The present studies used a choice procedure to assess the relative reinforcing strength of cocaine in group-housed male cynomolgus monkeys with extensive cocaine self-administration histories. Responding was maintained under a concurrent fixed-ratio 50 schedule of food and cocaine (0.003-0.1 mg/kg per injection) presentation. Responding on the cocaine-associated lever increased as a function of cocaine dose in all monkeys. Although response distribution was similar across social rank when saline or relatively low or high cocaine doses were the alternative to food, planned t tests indicated that cocaine choice was significantly greater in subordinate monkeys when choice was between an intermediate dose (0.01 mg/kg) and food. When a between-session progressive-ratio procedure was used to increase response requirements for the preferred reinforcer (either cocaine or food), choice of that reinforcer decreased in all monkeys. The average response requirement that produced a shift in response allocation from the cocaine-associated lever to the food-associated lever was higher in subordinates across cocaine doses, an effect that trended toward significance (p = 0.053). These data indicate that despite an extensive history of cocaine self-administration, most subordinate monkeys were more sensitive to the relative reinforcing strength of cocaine than dominant monkeys.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/36719
Item Type	Article
Refereed	Yes
Divisions	Life Sciences > School of Psychology and Clinical Language Sciences > Department of Psychology
Publisher	American Society for Pharmacology and Experimental Therapeutics
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