The effect of cocaine and D-amphetamine on punished responding

Various dosages of d-amphetamine (0.1, 0.5, 2.5 mg/kg) and of cocaine (5.0, 20, 40 mg/kg) were administered i.p. to each of 7 rats trained in an experimentally induced conflict procedure. Sessions were 1 hr in duration and consisted of five 12 min periods; responding was reinforced with food on a F124 sec schedule of reinforcement during each period; however, in periods 2 and 4 each response was followed by the application of footshock. Significant increase in responding did not occur in any period following any of the pretreatments. Cocaine (5.0, 20 mg/kg) and d-amphetamine (0.5, 2.5 mg/kg) significantly decreased responding in both punished and unpunished periods. Following these treatments the rate of responding in punished and unpunished components was not significantly different. This suggest that psychomotor stimulants may not selectively increase anxiety, at least at dosages which are not at the same time anorexic.