Effects of intravenous cocaine, diethylpropion, d-amphetamine and perphenazine on responding maintained by food delivery and shock avoidance in rhesus monkeys.

The effects of perphenazine, cocaine, diethylpropion and d-amphetamine on responding maintained by both food delivery and electric shock avoidance were determined using a multiple schedule of reinforcement in rhesus monkeys. This schedule had three components, each separated by a timeout: a fixed-ratio schedule of food delivery, a schedule of spaced responding (differential reinforcement of low rates) maintained by food delivery and a fixed-ratio schedule of shock avoidance. Control rates of responding on both ratio schedules were similar and were high relative to the low rates generated by the schedule of spaced responding. Perphenazine decreased rates on all three schedules in a dose-dependent fashion. All three psychomotor stimulants decreased food-maintained ratio responding at doses which had little effect on or increased rates of shock avoidance. Except for diethylpropion and d-amphetamine in one animal in which rates were increased, low rates of spaced responding were also decreased.