Passive avoidance learning in the rat as functions of d-amphetamine dosage and shock intensity.

The effects of d-amphetamine dosage (0, 1, 3, and 5 mg/kg) and shock intensity (0.2, 0.5, and 0.8 ma) on the learning of a passive avoidance response were assessed in rats. A curvilinear dose-response relationship was found at all shock levels, showing slower learning under moderate doses of d-amphetamine. The lowest shock level produced slower learning, especially in conjunction with the lowest dose of d-amphetamine. Results are discussed in terms of freezing behavior.