Morphine as a conditioned stimulus in a conditioned emotional response paradigm.
A Pavlovian conditioning experiment was conducted to determine whether morphine (6 mg/kg, IP) could act as a conditioned stimulus (CS) when paired with an electric shock unconditioned stimulus (US), and later produce a conditioned suppression of drinking (CR) in water deprived rats. Seven groups were tested for conditioning after exposure to one of the following conditioning procedures: (1) morphine paired with shock; (2) morphine alone with no shock; (3) shock but no morphine; (4) no shock and no morphine; (5) morphine paired with vocalizations of shocked rats; (6) saline paired with shock; (7) saline alone with no shock. Groups 1 and 2 tested whether morphine could act as a CS. Groups 3 and 4 tested for sensitization. Group 5 tested whether exposure to the vocalizations of other rats could act as a US when paired with a morphine CS. Groups 6 and 7 tested whether cues associated with the injection procedure could act as a CS. Only subjects in group 1 showed conditioned suppression of drinking, when compared to control groups. Overall, the results indicate that morphine could act as a conditioned stimulus and that several of the more obvious possible sources of artifact did not significantly contribute to the CR that is produced.
Bormann
N M
NM
Department of Psychology, Temple University, Philadelphia, PA 19122.
Overton
D A
DA
D000818:Animals; D003214:Conditioning, Classical / Q000187:drug effects*; D004327:Drinking Behavior / Q000187:drug effects; D004597:Electroshock; D004644:Emotions / Q000187:drug effects*; D008297:Male; D009020:Morphine / Q000494:pharmacology*; D051381:Rats; D012527:Satiation / Q000187:drug effects; D014828:Vocalization, Animal / Q000187:drug effects
D009020:Morphine