Psychopharmacology

, Volume 97, Issue 2, pp 179–182

Effects of fixed ratio size and dose on phencyclidine self-administration by rats

  • Karen L. Marquis
  • Michael G. Webb
  • J. Edward Moreton
Original Investigations

DOI: 10.1007/BF00442246

Cite this article as:
Marquis, K.L., Webb, M.G. & Moreton, J.E. Psychopharmacology (1989) 97: 179. doi:10.1007/BF00442246

Abstract

Female Sprague-Dawley rats were trained to self-administer phencyclidine (PCP; 0.125, 0.25, or 0.5 mg/kg/injection) on a fixed ratio (FR) schedule of reinforcement under limited access conditions (3 h). Initial training began with cocaine, which was later replaced with ketamine and then one of the three unit doses of PCP. Baseline rates of injection were determined at RF 10. The size of the ratio was then incremented geometrically every fifth daily session. Increasing the ratio resulted in a decrease in the number of injections per session. Furthermore, this decrease was greater for the 0.25 mg/kg dose than for the 0.5 mg/kg unit dose. The self-administration of the 0.125 mg/kg dose was variable and rapidly extinguished upon the increase in fixed ratio. The results indicate that PCP is self-administered by rats under the conditions imposed in this study. Furthermore, the relative reinforcing efficacy of the different unit doses of PCP could be discriminated using this type of response cost procedure.

Key words

RatsSelf-administrationPhencyclidineReinforcementFixed ratio

Copyright information

© Springer-Verlag 1989

Authors and Affiliations

  • Karen L. Marquis
    • 1
  • Michael G. Webb
    • 1
  • J. Edward Moreton
    • 1
  1. 1.Department of Pharmacology and Toxicology, School of PharmacyUniversity of MarylandBaltimoreUSA