Effect of morphine in combination with chlorpromazine and haloperiodol on operant behavior.
Using a discrete-trial avoidance-escape schedule in rats the interactions of morphine (M), chlorpromazine (C) and Haloperidol (H) were studied. All three drugs given alone or in combination disrupted operant behavior. At low doses C and H potentiated each other's effect, while at high doses antagonism could be observed. When combinations of M with C or H were tested, no antagonism or synergism was detected. Based on the statistical considerations used, it seems to be confirmed that the reflex inhibitory action of neuroleptics and M are mediated by independent receptor populations.
D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects; D002746:Chlorpromazine / Q000494:pharmacology*; D003216:Conditioning, Operant / Q000187:drug effects*; D004347:Drug Interactions; D006220:Haloperidol / Q000494:pharmacology*; D008297:Male; D009020:Morphine / Q000494:pharmacology*; D051381:Rats
D009020:Morphine; D006220:Haloperidol; D002746:Chlorpromazine