Picker M, Massie C A, Dykstra L A
Department of Psychology, University of North Carolina at Chapel Hill 27514.
Psychopharmacology (Berl). 1987;93(2):230-6. doi: 10.1007/BF00179940.
The effects of several opioid agonists and antagonists were examined in pigeons performing under a delayed matching-to-sample procedure. The mu agonists morphine and l-methadone, the kappa agonists U 50,488 and ethylketocyclazocine, and the opioid antagonist naloxone had no effect on the accuracy of responding. These drugs were, however, behaviorally active as evidenced by the dose-dependent decreases in rates of responding associated with their administration. In contrast, the sigma agonists (+) N-allylnormetazocine and phencyclidine decreased the accuracy of responding in a dose-dependent fashion. The relative magnitude of these drug-induced decreases in accuracy were similar across the no delay (0-s), short (2-s), and long (8-s) delay intervals. For these drugs, accuracy-decreasing effects were obtained only at doses that reduced rates of responding. The results of the present investigation parallel those reported in pigeons responding under drug discrimination tasks, in which the discriminative stimulus properties produced by the mu and kappa agonists are similar to each other but distinguishable from those produced by the sigma agonists.
在采用延迟匹配样本程序的鸽子身上，研究了几种阿片类激动剂和拮抗剂的作用。μ激动剂吗啡和左旋美沙酮、κ激动剂U 50,488和乙基酮环唑辛以及阿片类拮抗剂纳洛酮对反应准确性没有影响。然而，这些药物具有行为活性，表现为给药后反应率呈剂量依赖性下降。相比之下，σ激动剂（+）N-烯丙基去甲左啡诺和苯环利定以剂量依赖性方式降低反应准确性。在无延迟（0秒）、短延迟（2秒）和长延迟（8秒）间隔条件下，这些药物引起的准确性下降的相对幅度相似。对于这些药物，只有在降低反应率的剂量下才会出现准确性下降的效应。本研究结果与在药物辨别任务中对鸽子进行反应研究时所报告的结果相似，其中μ和κ激动剂产生的辨别刺激特性彼此相似，但与σ激动剂产生的辨别刺激特性不同。
