Mechanosensitivity of Nav1.5, a voltage-sensitive sodium channel

被引:138
作者
Beyder, Arthur [1 ]
Rae, James L. [1 ]
Bernard, Cheryl [1 ]
Strege, Peter R. [1 ]
Sachs, Frederick [2 ]
Farrugia, Gianrico [1 ]
机构
[1] Mayo Clin, Enter Neurosci Program, Rochester, MN 55905 USA
[2] SUNY Buffalo, Ctr Single Mol Biophys Physiol & Biophys Sci, Buffalo, NY 14260 USA
来源
JOURNAL OF PHYSIOLOGY-LONDON | 2010年 / 588卷 / 24期
关键词
SMOOTH-MUSCLE-CELLS; DEPENDENT K+ CHANNEL; ION CHANNELS; MEMBRANE MECHANICS; INTERSTITIAL-CELLS; PATCH RECORDINGS; CALCIUM-CHANNEL; PLASMA-MEMBRANE; QT-SYNDROME; HEK CELLS;
D O I
10.1113/jphysiol.2010.199034
中图分类号
Q189 [神经科学];
学科分类号
071006 [神经生物学];
摘要
The voltage-sensitive sodium channel Na(v)1.5 (encoded by SCN5A) is expressed in electromechanical organs and is mechanosensitive. This study aimed to determine the mechanosensitive transitions of Na(v)1.5 at the molecular level. Na(v)1.5 was expressed in HEK 293 cells and mechanosensitivity was studied in cell-attached patches. Patch pressure up to -50 mmHg produced increases in current and large hyperpolarizing shifts of voltage dependence with graded shifts of half-activation and half-inactivation voltages (delta V-1/2) by similar to 0.7 mV mmHg-1. Voltage dependence shifts affected channel kinetics by a single constant. This suggested that stretch accelerated only one of the activation transitions. Stretch accelerated voltage sensor movement, but not rate constants for gate opening and fast inactivation. Stretch also appeared to stabilize the inactivated states, since recovery from inactivation was slowed with stretch. Unitary conductance and maximum open probability were unaffected by stretch, but peak current was increased due to an increased number of active channels. Stretch effects were partially reversible, but recovery following a single stretch cycle required minutes. These data suggest that mechanical activation of Na(v)1.5 results in dose-dependent voltage dependence shifts of activation and inactivation due to mechanical modulation of the voltage sensors.
引用
收藏
页码:4969 / 4985
页数:17
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