Effects of ethylketazocine and morphine alone and in combination with naloxone on schedule-controlled behavior in pigeons.
The behavioral effects of morphine and ethylketazocine were compared in pigeons responding under multiple fixed-interval, fixed-ratio schedules of food presentation. Both morphine and ethylketazocine produced dose-related decreases in rates of responding maintained under either schedule. Maximal effects of morphine were observed about 15-45 min after injection and typically lasted the entire session (about 60 min). Effects of ethylketazocine had a faster onset (maximal effects were observed within 15 min after injection), and shorter duration (effects diminished within the session). Ethylketazocine and morphine had similar potencies. Dose-effect curves for both drugs were shifted to a similar degree by naloxone.
D000701:Analgesics, Opioid / Q000494:pharmacology*; D000818:Animals; D010856:Columbidae; D003216:Conditioning, Operant / Q000187:drug effects*; D003496:Cyclazocine / Q000031:analogs & derivatives* / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D016314:Ethylketocyclazocine; D008297:Male; D009020:Morphine / Q000494:pharmacology*; D009270:Naloxone / Q000494:pharmacology*; D012055:Reinforcement Schedule
D000701:Analgesics, Opioid; D009270:Naloxone; D016314:Ethylketocyclazocine; D009020:Morphine; D003496:Cyclazocine