Chloride currents across the membrane of mammalian skeletal muscle fibres.
Chloride currents across the membrane of mammalian skeletal muscle fibres.
复制标题
氯化物电流穿过哺乳动物骨骼肌纤维的膜。
DOI：
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发表时间：
1995
期刊：
影响因子：
--
通讯作者：
R. Rüdel
中科院分区：
文献类型：
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作者：
C. Fahlke;R. Rüdel
1.氯电流通过膜的大鼠腰大肌肌纤维节段进行了研究与双凡士林间隙的条件下，最大限度地减少其他离子的电流。2.在不含Cl（-）的溶液中，观察到1.1 +/-0.4 microS的时间和电压无关电导。3.与完整纤维一样，稳态Cl-电导率为2.5 +/-0.9 mS cm-2;卤化物选择性为Cl-> Br-> I-，Cl-电流完全被0.1 mM 9-蒽羧酸（9-AC）阻断。4.从-85 mV到-125和+55 mV之间的电压阶跃引起电流，在超极化时失活，在去极化时激活。激活用两个指数拟合，较小的时间常数从+55 mV的37.5 ms增加到-5 mV的67.0 ms，较大的时间常数（450 ms）与比-5 mV更正的电位无关。两个失活时间常数的范围为30.6（-105 mV）和99.3 ms（-35 mV），以及139.4（-105 mV）和738.5 ms（-35 mV）。5.激活曲线符合玻尔兹曼分布（半峰，-39 mV;在导通点的斜率，1/17.2 mV）。停用不完整。在非常负的电位下，大约四分之一的最大通道数是开放的。6.当用5和61 mM细胞内Cl-浓度（[Cl-]i）进行测试时，动力学参数没有差异。7.在持续> 5 s的去极化期间，激活随后下降。随着逐渐变长的前脉冲变为正的反转电位和测试脉冲变为负的，对测试和前脉冲的响应以相似的时间常数下降，这表明了真实的失活过程。
1. Chloride currents through the membrane of rat psoas muscle fibre segments were investigated with a double Vaseline gap under conditions minimizing the currents of other ion species. 2. In Cl(‐)‐free solutions a time‐ and voltage‐independent conductance of 1.1 +/‐ 0.4 microS was observed. 3. As with intact fibres, the steady‐state Cl‐ conductance was 2.5 +/‐ 0.9 mS cm‐2; the halide selectivity was Cl‐ > Br‐ > I‐, and Cl‐ currents were completely blocked by 0.1 mM 9‐anthracene carboxylic acid (9‐AC). 4. Voltage steps from ‐85 mV to between ‐125 and +55 mV elicited currents with deactivation upon hyperpolarization and activation upon depolarization. Activation was fitted with two exponentials, the smaller time constant increasing from 37.5 ms at +55 mV to 67.0 ms at ‐5 mV, the larger time constant (450 ms) being independent of potentials more positive than ‐5 mV. The two deactivation time constants ranged between 30.6 (‐105 mV) and 99.3 ms (‐35 mV), and 139.4 (‐105 mV) and 738.5 ms (‐35 mV). 5. The activation curve was fitted with a Boltzmann distribution (half‐maximum, ‐39 mV; slope at inflexion point, 1/17.2 mV). Deactivation was incomplete. At very negative potentials about one‐quarter of the maximum number of channels were open. 6. When tested with 5 and 61 mM intracellular Cl‐ concentration ([Cl‐]i) the kinetic parameters were not different. 7. During depolarizations lasting > 5 s, activation was followed by a decline. With progressively longer prepulses going positive to the reversal potential and test pulses going negative, the responses to test and prepulses decreased with similar time constants, suggesting a real inactivation process.
成年大鼠骨骼肌表面膜离子通道的表征。
影响因子：
3.4
作者：
Chua,M;Betz,WJ
通讯作者：
Betz,WJ