Instrumental reflex reinforced with intragastric infusion of morphine.
D000818:Animals; D003216:Conditioning, Operant / Q000187:drug effects; D005247:Feeding Behavior; D006801:Humans; D008297:Male; D008722:Methods; D009020:Morphine / Q000008:administration & dosage / Q000494:pharmacology*; D009021:Morphine Dependence; D051381:Rats; D012018:Reflex / Q000187:drug effects*; D012054:Reinforcement, Psychology; D012653:Self Stimulation; D012903:Smell; D013270:Stomach; D013649:Taste
D009020:Morphine