BIA 已合呼时8FHf ch nei ACh aCh p吧 Nerve ACh/Ca terminalIa+ K K+ ACh Na Nat K Outside Muscle membrane N N Inside K K Kt K Kt K KK 12 + Outside Inside Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ Na+ K+ K+ K+ K+ K+ K+ K+ K+ K+ K+ K+ ACh ACh ACh Ca2+ induces fusion of vesicles with nerve terminal membrane. ACh is released and diffuses across synaptic cleft. ACh ACh binds to its receptor on the postsynaptic membrane Binding of ACh opens channel pore that is permeable to Na+ and K+ . Na+ Na+ K+ Muscle membrane Ca2+ Ca2+