Na+60 90 回Na Nat Nat Na+60-Na 回血 0 90 mV Vm=-65 mV Vm=o mv 60 Na №a+60 30 m=+20m Vm=+30 mV the m gate, the h gate tends to open the channel close the channel as vm as Vm becomes less becomes less negative. negative. Hence, this is Hence this is called an called an activation gate. inactivation gate
the m gate, tends to open the channel as Vm becomes less negative. Hence, this is called an activation gate. the h gate, close the channel as Vm becomes less negative. Hence, this is called an inactivation gate
Regenerative The consequent change in Vm opens more m gates and augments the inward Nat current. As Vm approaches about 65 mV, the remaining m gates rapidly swing open in the fast Nat channels until virtually all the m gates are open Effective refractory period The h gates then remain closed until the cell has partially repolarized during phase 3, in this time the cell is in its effective refractory period, and it will not respond to further excitation Recovered from inactivation a+通道有三种状态,都是电压依赖性的: 备用(-90mV)→激活→失活
The consequent change in Vm opens more m gates and augments the inward Na+ current. As Vm approaches about -65 mV, the remaining m gates rapidly swing open in the fast Na+ channels until virtually all the m gates are open Regenerative The h gates then remain closed until the cell has partially repolarized during phase 3, in this time the cell is in its effective refractory period, and it will not respond to further excitation. Effective refractory period Na+通道有三种状态，都是电压依赖性的： 备用 (-90 mV) → 激活 → 失活 Recovered from inactivation
Phase 1 is genesis of early repolarization Two mechanisms are responsible for phase 1 CL=300 msec BCL= 8000 msec When a notch is not evidence phase l reflects the inactivation of the fast nat channels In cells characterized by a notch, phase I reflects not only the inactivation of nat channels but also activation of a specific K current(transient outward Endo current lto
Phase 1 is genesis of early repolarization • When a notch is not evidence, phase 1 reflects the inactivation of the fast Na+ channels. Two mechanisms are responsible for phase 1: • In cells characterized by a notch, phase 1 reflects not only the inactivation of Na+ channels, but also activation of a specific K+ current (transient outward current [Ito]
2003年诺贝尔化学奖获得者彼得·阿格雷 东方网10月9日消息:10月8日,瑞典皇家科学院在瑞典首都斯德哥尔摩宣布,将2003 年诺贝尔化学奖授予美国科学家彼得·阿格雷和罗德里克·麦金农,分别表彰他们发现细 胞膜水通道,以及对离子通道结构和机理研究作岀的开创性贡献
Roderick mackinnon 罗德里克麦金农 Rockefeller University Howard Hughes Medical Institute New York, NY, UsA
Roderick MacKinnon 罗德里克.麦金农 Rockefeller University, Howard Hughes Medical Institute New York, NY, USA