title: Prevention by naltrexone of tolerance to the rate-decreasing effects of morphine on schedule-controlled responding in the pigeon.
mesh_terms: D000818:Animals; D010856:Columbidae; D003216:Conditioning, Operant / Q000187:drug effects*; D004361:Drug Tolerance; D008297:Male; D009020:Morphine / Q000037:antagonists & inhibitors*; D009270:Naloxone / Q000031:analogs & derivatives*; D009271:Naltrexone / Q000494:pharmacology*; D012055:Reinforcement Schedule; D013997:Time Factors
chemical_list: D009270:Naloxone; D009271:Naltrexone; D009020:Morphine