, Volume 122, Issue 4, pp 346–350

Haloperidol differentially affects reinforcement and motivational processes in rats running an alley for intravenous heroin

  • K. McFarland
  • A. Ettenberg
Original Investigation

DOI: 10.1007/BF02246264

Cite this article as:
McFarland, K. & Ettenberg, A. Psychopharmacology (1995) 122: 346. doi:10.1007/BF02246264


The role of drug-paired environmental stimuli in opiate self-administration was investigated by exposing animals to discrete cues that were predictive of the availability or unavailability of heroin reinforcement. Rats were trained to traverse a straight arm runway for a reinforcement consisting of a single 0.1 mg/kg intravenous infusion of heroin delivered upon entrance to the goal box. On each trial, one of two discriminative olfactory stimuli (orange and almond) was used: one which signaled the availability of heroin in the goal box (S+), and one which signaled its absence (S−). The effect of dopamine (DA) receptor antagonism on reinforcement and motivational processes was investigated by pretreating subjects with 0.0, 0.15 or 0.30 mg/kg of the DA receptor antagonist drug, haloperidol. Haloperidol had no effect on operant runway performance (i.e. goal time) in any condition. However, 24 h later, on the first post-treatment trial, those haloperidol animals that received heroin in the goal box on the previous trial (i.e. the S+ condition) ran reliably more slowly than subjects that received vehicle on the previous S+ trial. These results suggest that haloperidol does not affect the motivational properties of stimuli which predict the availability of heroin, while it does diminish the reinforcing effects of actually receiving heroin.

Key words

Heroin self-administration Reinforcement Motivation Discriminative stimulus Haloperidol Dopamine 

Copyright information

© Springer-Verlag 1995

Authors and Affiliations

  • K. McFarland
    • 1
  • A. Ettenberg
    • 1
  1. 1.Behavioral Pharmacology Laboratory, Department of PsychologyUniversity of CaliforniaSanta BarbaraUSA

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