Meisch R A, Lemaire G A
Department of Psychiatry and Behavioral Sciences, University of Texas Health Science Center, Houston 77030.
Pharmacol Biochem Behav. 1990 Feb;35(2):443-50. doi: 10.1016/0091-3057(90)90182-h.
The reinforcing effects of an orally delivered combination of 1 mg/ml pentobarbital plus 1% ethanol were evaluated in four rhesus monkeys. The drug combination and another liquid (either water, 1 mg/ml pentobarbital, or 1% ethanol) were concurrently available under identical fixed-ratio (FR) schedules. Substantially higher response rates were maintained by the drug combination than by any of the three other liquids. Thus, the reinforcing effects of the pentobarbital-ethanol combination were greater than those of either component drug. In a second experiment, water (the vehicle) was concurrently available with one other liquid (1 mg/ml pentobarbital, 1% ethanol, or the pentobarbital-ethanol combination). All three drug solutions functioned as reinforcers since they maintained much higher response rates than water. These results demonstrate that the greater relative reinforcing effects of the drug combination in the first experiment were not due to a lack of reinforcing effects of the 1 mg/ml pentobarbital or 1% ethanol solutions. In a final experiment, the drug combination was scheduled concurrently with 1 mg/ml pentobarbital, and FR size was systematically varied. The drug combination was then scheduled concurrently with 1% ethanol, and FR size was again varied. As FR size increased, the relative amount of responding maintained by the drug combination increased. Thus, differences in relative reinforcing effects that were evident in the first experiment were again evident in the final experiment when appropriate schedule-parameter values were used.
在四只恒河猴身上评估了口服1毫克/毫升戊巴比妥与1%乙醇组合的强化效果。药物组合和另一种液体（水、1毫克/毫升戊巴比妥或1%乙醇）在相同的固定比率（FR）时间表下同时可供选择。与其他三种液体中的任何一种相比，药物组合维持的反应率要高得多。因此，戊巴比妥-乙醇组合的强化效果大于任何一种成分药物。在第二个实验中，水（赋形剂）与另一种液体（1毫克/毫升戊巴比妥、1%乙醇或戊巴比妥-乙醇组合）同时可供选择。所有三种药物溶液都起到了强化剂的作用，因为它们维持的反应率比水高得多。这些结果表明，在第一个实验中药物组合相对更大的强化效果并不是由于1毫克/毫升戊巴比妥或1%乙醇溶液缺乏强化效果。在最后一个实验中，药物组合与1毫克/毫升戊巴比妥同时安排，FR大小系统地变化。然后将药物组合与1%乙醇同时安排，FR大小再次变化。随着FR大小的增加，药物组合维持的反应相对量增加。因此，当使用适当的时间表参数值时，在最后一个实验中再次明显出现了在第一个实验中明显的相对强化效果差异。
