Bevins R A, Klebaur J E, Bardo M T
Department of Psychology, University of Nebraska, Lincoln 68588-0308, USA.
Pharmacol Biochem Behav. 1997 Oct;58(2):485-90. doi: 10.1016/s0091-3057(97)00288-8.
Rats were trained on a d-amphetamine (1 mg/kg) vs. saline discrimination task using food-maintained responding (fixed ratio = 25). In extinction tests, drug-appropriate responding decreased as the dose of amphetamine was substituted for the training dose decreased. The dopamine D2/D3 receptor agonist (+/-)7-hydroxy-N,N-di-n-propyl-2-aminotetralin (7-OH-DPAT) substituted fully for the amphetamine discriminative stimulus at the higher doses examined (0.1, 0.3, 1.0 mg/kg). This substitution was accompanied by a substantial decrease in overall response rates. Eticlopride, a dopamine D2/D3 receptor antagonist, partially blocked 7-OH-DPAT substitution. Thus, at the higher doses, 7-OH-DPAT shared sufficient discriminative stimulus properties with the amphetamine to prompt full substitution. Eticlopride antagonism suggests a role for the D2/D3 dopamine receptor in this substitution.
大鼠接受了一项关于右旋苯丙胺（1毫克/千克）与生理盐水辨别任务的训练，采用食物强化反应（固定比率 = 25）。在消退测试中，随着替代训练剂量的苯丙胺剂量降低，与药物相关的反应也减少。多巴胺D2/D3受体激动剂（±）7-羟基-N,N-二正丙基-2-氨基四氢萘（7-OH-DPAT）在较高测试剂量（0.1、0.3、1.0毫克/千克）时完全替代了苯丙胺的辨别性刺激。这种替代伴随着总体反应率的大幅下降。多巴胺D2/D3受体拮抗剂依替必利部分阻断了7-OH-DPAT的替代作用。因此，在较高剂量时，7-OH-DPAT与苯丙胺具有足够的共同辨别性刺激特性，从而促使完全替代。依替必利的拮抗作用表明D2/D3多巴胺受体在这种替代中发挥作用。
