Influence of conditioned reinforcement on the response-maintaining effects of quinpirole in rats

Behav Pharmacol. 2009 Sep;20(5-6):492-504. doi: 10.1097/FBP.0b013e328330ad9b.

Abstract

D2-like agonists, such as quinpirole, maintain responding in monkeys, rats, and mice when they are substituted for cocaine. This study examined the influence of operant history and cocaine-paired stimuli (CS) on quinpirole-maintained responding in rats trained to nose poke for cocaine. Upon acquisition of responding for cocaine, substitutions were performed in the presence or absence of injection-CS pairings. Although cocaine maintained responding regardless of whether injections were accompanied by CS, quinpirole maintained responding only when CS were paired with injections. To assess the influence of operant history, injections of cocaine, quinpirole, remifentanil, nicotine, or saline were made available on a previously inactive lever, while nose pokes continued to result in CS presentation. Although responding was reallocated from the nose poke to the lever when cocaine or remifentanil was available, lever presses remained low, and nose poking persisted when quinpirole or nicotine was made contingent upon lever presses. Finally, quinpirole pretreatments resulted in high rates of nose poking when nose pokes resulted in CS presentation alone, but failed to maintain nose poking when the CS was omitted. Taken together, these results suggest that the response-maintaining effects of quinpirole are primarily mediated by an enhancement of the conditioned reinforcing effects of earlier CS, rather than by a reinforcing effect of quinpirole.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Analysis of Variance
  • Animals
  • Arabidopsis Proteins
  • Behavior, Animal / drug effects
  • Cocaine / administration & dosage
  • Conditioning, Classical / drug effects
  • Conditioning, Operant / drug effects*
  • Conditioning, Psychological / drug effects
  • Dopamine Agonists / pharmacology*
  • Dopamine Uptake Inhibitors / administration & dosage
  • Male
  • Nuclear Proteins
  • Quinpirole / pharmacology*
  • Rats
  • Rats, Sprague-Dawley
  • Reinforcement Schedule
  • Reinforcement, Psychology*
  • Self Administration

Substances

  • Arabidopsis Proteins
  • Dopamine Agonists
  • Dopamine Uptake Inhibitors
  • Nuclear Proteins
  • TIC protein, Arabidopsis
  • Quinpirole
  • Cocaine