Naloxone decreases responding for conditioned reinforcement in rats.
That opioids can mediate unconditioned reinforcement is well established, but there is little evidence indicating whether they modify conditioned reinforcement. Here, a tone which initially served as a discriminative stimulus for the availability of water reinforcement was established as a conditioned stimulus. When later given a choice between pressing a lever producing the tone (but not water) or one which produced no effect, rats chose the tone-producing lever 66% of the time. Naloxone (3.0 mg/kg) reduced overall responding and completely eliminated the preference for the tone-producing lever. Results are briefly discussed in terms of the importance of understanding mechanisms serving conditioned reinforcement.
Rudski
Jeffrey
J
Muhlenberg College, 2400 Chew Street, Allentown, PA 18104, USA. rudski@muhlenberg.edu
D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D003213:Conditioning, Psychological / Q000187:drug effects*; D008297:Male; D009270:Naloxone / Q000494:pharmacology*; D009292:Narcotic Antagonists / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012054:Reinforcement, Psychology
D009292:Narcotic Antagonists; D009270:Naloxone