Branch M N, Sizemore G M
Psychology Department, University of Florida, Gainesville 32611.
Pharmacol Biochem Behav. 1988 Jul;30(3):737-48. doi: 10.1016/0091-3057(88)90092-5.
Four food-deprived squirrel monkeys were trained to emit complex sequences of responses. The sequences involved pressing lighted response keys in orders dictated by colors that illuminated the keys, and ranged in length from two to five responses. Appropriate completion of these behavioral chains could be followed by food presentation. Acute administration of a range of doses (0.1-1.7 mg/kg) of cocaine hydrochloride produced dose-related decreases in the rate of completing chains and in accuracy of performance during chains. There was little evidence that the drug's effects on overall accuracy were related to the length of the chain. Three of the monkeys were exposed to daily administration of a large dose of cocaine, first after daily sessions and then prior to sessions. Daily postsession administration did not alter the dose-effect curves, but daily presession injection did, indicating the development of behavioral or "contingent" tolerance. In all cases, tolerance was accompanied by an increase in reinforcement frequency relative to the frequency observed following acute administration. Omission of the daily dose during presession drug administration resulted in performance near original control levels indicating essentially no withdrawal effect. The findings illustrate the importance of behavioral factors in the development of tolerance to cocaine in a primate.
对四只处于食物剥夺状态的松鼠猴进行训练，使其发出复杂的反应序列。这些序列包括按照照亮按键的颜色所规定的顺序按压发光的反应按键，长度从两个反应到五个反应不等。正确完成这些行为链后会有食物呈现。急性给予一系列剂量（0.1 - 1.7毫克/千克）的盐酸可卡因会导致完成行为链的速率以及行为链执行过程中的表现准确性出现与剂量相关的下降。几乎没有证据表明该药物对总体准确性的影响与行为链的长度有关。其中三只猴子每天接受大剂量可卡因给药，先是在每日实验结束后，然后是在实验前。每日实验结束后给药并未改变剂量 - 效应曲线，但每日实验前注射则改变了，这表明出现了行为性或“条件性”耐受性。在所有情况下，耐受性都伴随着相对于急性给药后观察到的强化频率增加。在实验前药物给药期间省略每日剂量会导致表现接近原始对照水平，表明基本没有戒断效应。这些发现说明了行为因素在灵长类动物对可卡因耐受性发展中的重要性。
