, Volume 108, Issue 3, pp 295–300

Effects of increasing response requirement on choice between cocaine and food in rhesus monkeys

  • Michael A. Nader
  • William L. Woolverton
Original Investigations

DOI: 10.1007/BF02245115

Cite this article as:
Nader, M.A. & Woolverton, W.L. Psychopharmacology (1992) 108: 295. doi:10.1007/BF02245115


Rhesus monkeys were trained in a discretetrials choice procedure and allowed to choose between intravenous injections of cocaine (0.01–1.0 mg/kg/injection) and food presentation (1 or 4 pellets; 1 g/pellet) during daily 7-h experimental sessions. When each reinforcer was available under a fixed-ratio (FR) 30 schedule, the frequency of cocaine choice and the total drug intake increased in a dose-related manner for all monkeys. When the FR for cocaine was differentially increased, the frequency of cocaine choice decreased, shifting the cocaine dose-response function to the right and/or downward. When the FR for cocaine was at least 480, cocaine preference could not be recovered up to doses of 1.0 mg/kg/injection. In a second experiment, when the response requirement for food was differentially increased, the frequency of cocaine choice increased. These results demonstrate that altering the response requirement for cocaine or for alternative reinforcers that are available can substantially affect cocaine self-administration.

Key words

Discrete-trials choice Self-administration Cocaine Progressive-ratio Alternative reinforcer Rhesus monkey 
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Copyright information

© Springer-Verlag 1992

Authors and Affiliations

  • Michael A. Nader
    • 1
  • William L. Woolverton
    • 1
    • 2
  1. 1.Department of PsychiatryThe University of ChicagoChicagoUSA
  2. 2.Department of Pharmacological and Physiological Sciences, Drug Abuse Research Center, Pritzker School of MedicineThe University of ChicagoChicagoUSA

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