Action of codeine, pethidine and methadone on the operant behavior of the rat.
D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects; D003061:Codeine / Q000494:pharmacology*; D003216:Conditioning, Operant / Q000187:drug effects*; D003864:Depression, Chemical; D008297:Male; D008614:Meperidine / Q000494:pharmacology*; D008691:Methadone / Q000494:pharmacology*; D051381:Rats; D012054:Reinforcement, Psychology
D008614:Meperidine; D008691:Methadone; D003061:Codeine