Effects of phencyclidine, haloperidol, and naloxone on fixed-interval performance in rats.
Phencyclidine (PCP), haloperidol, and naloxone were administered alone and in combination to rats responding under a fixed-interval schedule for water presentation. Lower doses of PCP (0.25-2.0 mg/kg) and naloxone (0.001-0.1 mg/kg) produced increases while higher doses produced dose-dependent decreases in response rate. Haloperidol (0.0625-0.5 mg/kg) produced a monotonic dose-dependent decrease in responding. When a dose of naloxone (8.0 mg/kg) that did not alter responding was administered prior to the PCP, the PCP dose-response curve was shifted to 6.5-fold lower doses of PCP. When a dose of haloperidol (0.0625 mg/kg) that did not alter responding was administered prior to the PCP, the PCP dose-response curve was shifted to 1.5-fold higher dose of PCP. These observations are discussed in relation to current views of the mechanism of PCP action.
D000818:Animals; D003216:Conditioning, Operant / Q000187:drug effects*; D006220:Haloperidol / Q000494:pharmacology*; D008297:Male; D009270:Naloxone / Q000494:pharmacology*; D010622:Phencyclidine / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D012055:Reinforcement Schedule
D009270:Naloxone; D010622:Phencyclidine; D006220:Haloperidol