Smith J B, Branch M N, McKearney J W
J Pharmacol Exp Ther. 1978 Oct;207(1):159-64.
Responses of squirrel monkeys adjusted the intensity of a continuous electric shock under two different schedules. In one schedule, responses decreased a shock intensity which otherwise was increased at a fixed rate (escape). In the other schedule, responses produced food pellets but also increased a shock intensity which otherwise decreased at a fixed rate (punishment). When animals were first studied under the escape schedule, d-amphetamine increased responding. Similarly, when animals had an intervening experience under the punishment schedule with no drugs administered, or when the drug was given but shock increments were tempoerarily eliminated during those drug sessions, d-amphetamine still increased subsequent escape responding. However, when animals under the punishment schedule were given d-amphetamine and shock increments occurred as usual during the drug session, the drug no longer increased either punished or subsequent escape responding. The effects of d-amphetamine on escape responding were completely different depending on the individual's prior drug experience.
松鼠猴的反应在两种不同的实验安排下调节了连续电击的强度。在一种实验安排中，反应会降低电击强度，否则电击强度会以固定速率增加（逃避）。在另一种实验安排中，反应会产生食物颗粒，但也会增加电击强度，否则电击强度会以固定速率降低（惩罚）。当动物首先在逃避实验安排下进行研究时，右旋苯丙胺增加了反应。同样，当动物在没有给药的惩罚实验安排下有中间经历时，或者当给药但在那些药物实验期间电击增量被暂时消除时，右旋苯丙胺仍然增加了随后的逃避反应。然而，当处于惩罚实验安排下的动物被给予右旋苯丙胺且在药物实验期间电击增量像往常一样出现时，药物不再增加受惩罚的反应或随后的逃避反应。右旋苯丙胺对逃避反应的影响完全不同，这取决于个体之前的药物经历。
