De Vry J, Koek W, Slangen J L
Psychopharmacology (Berl). 1984;83(3):257-61. doi: 10.1007/BF00464790.
Rats were trained to discriminate between fentanyl (0.04 mg/kg) and saline in a two-lever procedure. Using a FR 10 schedule of food reinforcement, drug-induced differences between the number of reinforcers obtained under fentanyl and saline conditions were observed. The effect of eliminating these differences on the outcome of generalization tests was investigated by different manipulations. In one group (N = 10), the FR 10 schedule used during saline sessions was changed to FR 6 during drug sessions. In a second group (N = 12), saline sessions ended after the number of reinforcers obtained was equal to the number obtained during the preceding drug session. A control group (N = 10) was trained using a FR 10 schedule under both conditions. Elimination of differences in reinforcement frequency accelerated the acquisition of the discrimination, diminished response bias, flattened the slope and reduced the ED50 value of generalization gradients of fentanyl, morphine and sufentanil and increased the ED50 value of naloxone in antagonizing 0.04 mg/kg fentanyl. It is concluded that the unconditioned effects of 0.04 mg/kg fentanyl on response rate in a FR 10 procedure lead to differences between saline and drug sessions which contribute to the apparent discriminative stimulus properties of fentanyl.
大鼠通过双杠杆程序接受训练，以区分芬太尼（0.04毫克/千克）和生理盐水。采用固定比率10（FR 10）的食物强化程序，观察了在芬太尼和生理盐水条件下获得的强化物数量之间的药物诱导差异。通过不同的操作研究了消除这些差异对泛化测试结果的影响。在一组（N = 10）中，生理盐水训练期间使用的FR 10程序在药物训练期间改为FR 6。在第二组（N = 12）中，在获得的强化物数量等于前一次药物训练期间获得的数量后，生理盐水训练结束。对照组（N = 10）在两种条件下均采用FR 10程序进行训练。消除强化频率差异加速了辨别学习的获得，减少了反应偏差，使斜率变平，降低了芬太尼、吗啡和舒芬太尼泛化梯度的半数有效剂量（ED50）值，并增加了纳洛酮拮抗0.0４毫克/千克芬太尼时的ED50值。得出的结论是，0.04毫克/千克芬太尼在FR 10程序中对反应率的非条件作用导致了生理盐水训练和药物训练之间的差异，这有助于芬太尼明显的辨别刺激特性。
