Effects of repeated administration of d-amphetamine on Sidman avoidance responding in rats.

The effects of repeated administration of d-amphetamine (0.5 mg/kg SC) on Sidman avoidance responding in rats were investigated. The response (lever-pressing) enhancing effect of d-amphetamine increased progressively after repeated administration. The change in behavior was more marked in the animals exposed to the avoidance situation during the period of the drug effect than in those given the drug after termination of each avoidance session. The present results suggest that the enhancing effect of d-amphetamine as demonstrated on Sidman avoidance responding in rats is dependent on the drug experience of the experimental animals and on the experimental situation to which the animals are exposed during the period of the drug effect.