Panlilio L V, Weiss S J, Thomas D A, Glowa J R
Department of Psychology, American University, Washington, DC 20016.
Psychopharmacology (Berl). 1992;108(1-2):185-8. doi: 10.1007/BF02245305.
Previous work (Thomas et al. 1990) showed that an anxiolytic benzodiazepine increased the time allocated to responding in a conflict situation (where responses were both food-reinforced and shock-punished) versus a nonpunishment situation. The present experiment tested whether a benzodiazepine-receptor inverse agonist (FG 7142, 1-30 mg/kg) would have the opposite effect (i.e., decrease time spent responding in a punishment situation). Chain pulls determined whether a rat's lever presses were reinforced on 1) a lean variable-interval schedule, or 2) a richer variable-interval schedule in which responding also produced shock intermittently. FG 7142 dose-dependently decreased nonpunished lever responding, but did not affect punished responding. The drug nonselectively decreased chain pulling (the schedule-switching response). Like chlordiazepoxide, FG 7142 increased the time spent in the punishment component, showing that not all effects of benzodiazepine-receptor agonists and inverse agonists are opposite. These results are inconsistent with expectations that anxiogenic actions of FG 7142 should 1) decrease punished responding; 2) increase the rate of responses that terminate the punishment condition; and 3) decrease time spent in the punishment component. Rather, nonsuppressed responding seems most sensitive to decreases by FG 7142.
先前的研究（托马斯等人，1990年）表明，一种抗焦虑苯二氮䓬类药物在冲突情境（反应既有食物强化又有电击惩罚）中与非惩罚情境相比，增加了用于反应的时间。本实验测试了一种苯二氮䓬受体反向激动剂（FG 7142，1 - 30毫克/千克）是否会产生相反的效果（即减少在惩罚情境中花费的反应时间）。链条拉动决定了大鼠的杠杆按压是否在以下两种情况下得到强化：1）在稀疏可变间隔时间表上，或者2）在更丰富的可变间隔时间表上，其中反应也会间歇性地产生电击。FG 7142剂量依赖性地减少了非惩罚性杠杆反应，但不影响惩罚性反应。该药物非选择性地减少了链条拉动（时间表切换反应）。与氯氮䓬一样，FG 7142增加了在惩罚部分花费的时间，表明并非苯二氮䓬受体激动剂和反向激动剂的所有作用都是相反的。这些结果与预期不符，即FG 7142的致焦虑作用应该：1）减少惩罚性反应；2）增加终止惩罚条件的反应速率；3）减少在惩罚部分花费的时间。相反，未受抑制的反应似乎对FG 7142的减少最为敏感。
