Effects of d-amphetamine and pentobarbital in combination with single or repeated daily injections of morphine in the pigeon.
D000818:Animals; D010856:Columbidae; D003216:Conditioning, Operant / Q000187:drug effects*; D003913:Dextroamphetamine / Q000494:pharmacology*; D004347:Drug Interactions; D004361:Drug Tolerance; D008297:Male; D009020:Morphine / Q000494:pharmacology*; D010424:Pentobarbital / Q000494:pharmacology*; D012055:Reinforcement Schedule
D009020:Morphine; D010424:Pentobarbital; D003913:Dextroamphetamine