Fujita N, Saito K, Hirata A, Iwatsubo K, Noguchi Y, Yoshida H
Brain Res. 1980 Oct 20;199(2):335-42. doi: 10.1016/0006-8993(80)90693-9.
Effects of dopaminergic agonists and antagonists on [3H]apomorphine binding to striatal membranes of rat brain was examined. Haloperidol and spiroperidol exhibited biphasic inhibition of [3H]apomorphine binding; one of which had the Hill coefficient of 0.9, whereas the other had that of 0.4. The former accounted for 65% of [3H]apomorphine binding while the latter consisted of 35% of the binding. Furthermore, the latter disappeared after kainic acid lesions. On the other hand, sulpiride and metoclopramide reduced [3H]apomorphine binding to 31% with the Hill coefficient of 0.9. The inhibition of [3H]apomorphine binding with the Hill coefficient of 0.4 which was shown by haloperidol and spiroperidol was not observed for sulpiride and metoclopramide. Previously, we demonstrated non- and positive-cooperative [3H]apomorphine binding to stiatal membranes. In the present study, it has been also shown that sulpiride inhibits non-cooperative [3H]apomorphine binding leaving that with allosteric properties unaffected. No inhibition of dopamine-sensitive adenylate cyclase was observed by 10(-4) M sulpiride while 90% inhibition was obtained with 10(-5) M haloperidol. From those results, it is suggested that non-cooperative [3H]spomorphine binding is not coupled with dopamine-sensitive adenylate cyclase.
研究了多巴胺能激动剂和拮抗剂对[3H]阿扑吗啡与大鼠脑纹状体膜结合的影响。氟哌啶醇和螺哌啶醇对[3H]阿扑吗啡结合表现出双相抑制作用；其中一种的希尔系数为0.9，而另一种为0.4。前者占[3H]阿扑吗啡结合的65%，而后者占结合的35%。此外，后者在 kainic 酸损伤后消失。另一方面，舒必利和甲氧氯普胺将[3H]阿扑吗啡结合减少到31%，希尔系数为0.9。舒必利和甲氧氯普胺未观察到氟哌啶醇和螺哌啶醇所显示的希尔系数为0.4的对[3H]阿扑吗啡结合的抑制作用。此前，我们证明了[3H]阿扑吗啡与纹状体膜的非协同和正协同结合。在本研究中，还表明舒必利抑制非协同[3H]阿扑吗啡结合，而不影响具有变构性质的结合。10(-4)M舒必利未观察到对多巴胺敏感的腺苷酸环化酶的抑制作用，而10(-5)M氟哌啶醇则有90%的抑制作用。从这些结果表明，非协同[3H]阿扑吗啡结合与多巴胺敏感的腺苷酸环化酶不偶联。
