Dascal N, Landau E M
Proc Natl Acad Sci U S A. 1982 May;79(9):3052-6. doi: 10.1073/pnas.79.9.3052.
Acetylcholine (AcCho) elicits four distinct membrane responses in Xenopus oocytes; the responses can be studied by using the voltage clamp technique. The fastest of the responses, a transient inward current (D1 response), is muscarinic, being evoked by oxotremorine and blocked by atropine but not by curare or hexamethonium. The action of AcCho is cooperative, three transmitter-receptor complexes being required to cause a membrane conductance change, and the dose-response curve in most cases can be fitted by an equation assuming the existence of two binding sites with an affinity ratio of about 11. Guanosine 3',5'-cyclic monophosphate and the 8-bromo and dibutyryl derivatives cause a response similar to D1 in both its time course and the underlying ionic mechanism. The nucleotide-generated response has a smaller amplitude than the AcCho-generated D1.
乙酰胆碱（AcCho）在非洲爪蟾卵母细胞中引发四种不同的膜反应；这些反应可用电压钳技术进行研究。最快的反应，即瞬时内向电流（D1反应），是毒蕈碱性的，由氧化震颤素诱发，可被阿托品阻断，但不能被箭毒或六甲铵阻断。AcCho的作用具有协同性，需要三个递质-受体复合物才能引起膜电导变化，并且在大多数情况下，剂量-反应曲线可以用一个假设存在两个亲和力比约为11的结合位点的方程来拟合。鸟苷3',5'-环磷酸及其8-溴和二丁酰衍生物在时间进程和潜在离子机制方面都引发与D1相似的反应。核苷酸产生的反应幅度比AcCho产生的D1小。
