The Journal of pharmacology and experimental therapeutics
-
J. Pharmacol. Exp. Ther. · Sep 1981
Drug effects on multiple and alternating mixed-schedule performance.
The effects of d-amphetamine, pentobarbital, morphine, chlorpromazine and triflupromazine were determined on key pecking by pigeons maintained under multiple and alternating-mixed fixed-ratio 30, fixed-interval 5-min schedules of grain presentation. Similar schedule performances were maintained under both the multiple and alternating mixed schedules. The effects of d-amphetamine and pentobarbital were similar under the multiple and alternating mixed schedules. ⋯ The effects of morphine, chlorpromazine and triflupromazine on fixed-interval rates of responding did not differ between the multiple and alternating mixed schedules. However, morphine, chlorpromazine and triflupromazine decreased responding under the alternating mixed fixed-ratio without affecting responding under the multiple fixed-ratio component. This selective decrease in fixed-ratio responding under the alternating mixed schedule by morphine, chlorpromazine and triflupromazine appears to be functionally similar to the effects of these drugs to decrease avoidance responding without affecting escape responding.
-
J. Pharmacol. Exp. Ther. · Sep 1981
Effects of d-amphetamine on responding of squirrel monkeys maintained under second-order schedules of food presentation, electric shock presentation or stimulus-shock termination.
The effects of d-amphetamine (0.01-5.6 mg/kg i.m.) were studied on lever pressing of squirrel monkeys maintained under various second-order schedules by a visual stimulus (S) that, with separate monkeys, was occasionally paired with the presentation of either food, electric shock or with the termination of a stimulus in the presence of which shocks occurred. Under one condition, the first response after 5 min produced a 3-sec stimulus change and the fourth stimulus change was followed immediately by food delivery, electric shock presentation or by the termination of a stimulus in the presence of which shocks occurred [fixed-ratio (FR); fixed-interval (FI) [FR 4 (FI 5-min:S)]. ⋯ Low to intermediate doses of d-amphetamine (0.03-0.3 mg/kg) generally increased and higher doses (0.56-5.6 mg/kg) decreased responding under all conditions. The effects of d-amphetamine on responding maintained by brief stimuli under different types of second-order schedules are generally similar, regardless of the type of reinforcing event or particular second-order schedule.