COMPARING EFFECTS OF ANILERIDINE, ALPHAPRODINE AND FENTANYL ON SCHEDULE-CONTROLLED RESPONDING BY PIGEONS

Abstract

The effects of anileridine, alphaprodine and fentanyl were studied on responding by pigeons under a multiple fixed-ratio, fixed-interval schedule of food presentation. All 3 drugs produced dose-related decreases in responding under both components of the multiple schedule, but rate increases were observed after low doses of anileridine and alphaprodine in some birds. Naloxone (1 mg/kg) antagonized the rate-increasing and rate-decreasing effects of doses of anileridine and alphaprodine of 10 mg/kg or less, whereas the effects of higher doses were not antagonized by naloxone. Likewise, chronic methadone or morphine (120 mg/kg per day p.o. [oral administration]) dosing produced only a slight cross-tolerance to the rate-decreasing effects of anileridine and alphaprodine. Naloxone (0.01, 0.1 and 1 mg/kg) and chronic methadone or morphine administration shifted the dose-effect curve for fentanyl to the right, indicating narcotic antagonism and methadone and morphine-induced cross-tolerance. The rate-decreasing effects of anileridine and alphaprodine are apparently related only slightly to narcotic effects. The rate-decreasing effects of fentanyl are primarily narcotic effects.