Properties of aconitine-modified sodium channels in single cells of mouse ventricular myocardium.
Properties of aconitine-modified sodium channels in single cells of mouse ventricular myocardium.
复制标题
小鼠心室心肌单细胞乌头碱修饰钠通道的特性。
DOI：
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发表时间：
1986
影响因子：
1.5
通讯作者：
K. Benndorf
中科院分区：
文献类型：
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作者：
B. Nilius;W. Boldt;K. Benndorf
在酶法分离的小鼠心室心肌单细胞中研究了植物生物碱乌头碱对钠通道动力学的影响。乌头碱 (1 mumol/l) 诱导动作电位 90% 复极化从 52.4 +/- 3.7 ms 延长至 217.0 +/- 12.5 ms。延迟终末复极和振荡后电位先于高频自发活动。峰值钠电流从 28.0 +/- 9.0 减少至 14.0 +/- 6.0 nA。钠电流的反转电位从 16.0 +/- 11.0 转变为 -8.0 +/- 6.0 mV（52.5 mmol/l 细胞外钠浓度），表明乌头碱修饰的 Na 通道的选择性降低。 m 亲和力曲线以恒定斜率向更负电势移动 31 mV。 h 亲和力曲线向相同方向移动 13 mV。 h亲和力-电压关系的斜率参数从9.1+/-2.2mV扩大到15.6+/-4.4mV。 m 亲和力和 h 亲和力的变化导致“窗口”增加。生物碱修饰的通道在-40 mV负电势下极其缓慢地失活，但在-40 mV正电势下表现出快速且完全的失活。
Effects of the plant alkaloid Aconitine on the kinetics of sodium channels were studied in enzymatically isolated single cells of the mouse ventricular myocardium. Aconitine (1 mumol/l) induced a prolongation of the 90% repolarization of action potentials from 52.4 +/- 3.7 ms to 217.0 +/- 12.5 ms. Delayed terminal repolarization and oscillatory afterpotentials preceded spontaneous activity with high frequencies. Peak sodium currents were diminished from 28.0 +/- 9.0 to 14.0 +/- 6.0 nA. The reversal potential of the sodium current was shifted from 16.0 +/- 11.0 to -8.0 +/- 6.0 mV (52.5 mmol/l extracellular sodium concentration) suggesting a decreased selectivity of the Aconitine-modified Na channels. The m-affinity-curves were shifted 31 mV towards more negative potentials at a constant slope. The h affinity-curves were shifted in the same direction by 13 mV. The slope parameter of the h affinity-voltage relationship was enlarged from 9.1 +/- 2.2 mV to 15.6 +/- 4.4 mV. Shifts in m affinity and h affinity resulted in an increased "window". The alkaloid modified channels inactivated extremely slowly at potentials negative to -40 mV, but showed a fast and complete inactivation at potentials positive to -40 mV.