Nonner W, Spalding B C, Hille B
Nature. 1980 Mar 27;284(5754):360-3. doi: 10.1038/284360a0.
Excitation of nerve or muscle requires an orderly opening and closing of molecular pores, the ionic channels, in the plasma membrane. During the action potential, Na channels are opened (activated) by the advancing wave of depolarisation, contributing a pulse of inward sodium current, and then are closed again (inactivated) by the continued depolarisation. As one approach both to obtaining molecular information on the Na channel and towards further defining the recently discovered kinetic interactions of the inactivation and activation gating steps, we have surveyed here the effects of chemical agents reported to slow or prevent Na channel inactivation. We find that many of the agents studied by others on invertebrate giant axons or vertebrate nerve act on our frog skeletal muscle preparation. In addition, we have discovered that simply lowering the intracellular pH nearly eliminates inactivation. The activation mechanism seems to resist modification.
神经或肌肉的兴奋需要质膜中分子孔隙（离子通道）有序地开放和关闭。在动作电位期间，Na通道被去极化的推进波打开（激活），产生一股内向钠电流脉冲，然后通过持续的去极化再次关闭（失活）。作为获取Na通道分子信息以及进一步确定最近发现的失活和激活门控步骤动力学相互作用的一种方法，我们在此研究了据报道可减缓或阻止Na通道失活的化学试剂的作用。我们发现，其他人在无脊椎动物巨轴突或脊椎动物神经上研究的许多试剂对我们的青蛙骨骼肌标本也有作用。此外，我们发现简单地降低细胞内pH几乎可消除失活。激活机制似乎抵抗修饰。
