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arXiv 1503.05474physics.bio-phq-bio.NC
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膜Na+通道失活的速率函数的电压依赖性

Voltage dependence of rate functions for Na+ channel inactivation within a membrane

Samuel R Vaccaro

摘要:

Na+通道的失活发生在结构域DIV的带电S4片段的激活之后,随后是细胞内疏水基序的结合,其阻断通过离子孔的传导。Na+通道失活的电压依赖性通常取决于每个域DI至DIV的S4传感器的速率函数。如果调节Na+通道电导的单个电压传感器的激活耦合到两阶段失活过程,则失活和从失活恢复的速率函数以及Na+电流在变量m(t)和h(t)方面的时间依赖性可以从相互依赖的激活和失活的主方程的解导出。速率函数具有与Hodgkin-Huxley经验确定的表达式一致的电压依赖性,并且表现出去极化和超极化钳位电位的饱和。

英文摘要:

The inactivation of a Na+ channel occurs when the activation of the charged S4 segment of domain DIV is followed by the binding of an intracellular hydrophobic motif which blocks conduction through the ion pore. The voltage dependence of Na+ channel inactivation is, in general, dependent on the rate functions of the S4 sensors of each of the domains DI to DIV. If the activation of a single voltage sensor that regulates the Na+ channel conductance is coupled to a two-stage inactivation process, the rate functions for inactivation and recovery from inactivation, as well as the time dependence of the Na+ current in terms of the variables m(t) and h(t), may be derived from a solution to the master equation for interdependent activation and inactivation. The rate functions have a voltage dependence that is consistent with the Hodgkin-Huxley empirically determined expressions, and exhibit saturation for both depolarized and hyperpolarized clamp potentials.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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