Temperature dependence of human muscle ClC-1 chloride channel
Temperature dependence of human muscle ClC-1 chloride channel
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DOI：
10.1111/j.1469-7793.2001.t01-1-00083.x
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发表时间：
2001-08-15
影响因子：
5.5
通讯作者：
Rychkov, GY
中科院分区：
文献类型：
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作者：
Bennetts, B;Roberts, ML;Rychkov, GY
1. 在目前的工作中，我们研究了在人胚胎肾（HEK 293）细胞中瞬时表达的人肌肉ClC-1 氯离子通道的离子电导和门控对温度的依赖性。2．在正常 pH 值下，ClC-1 电流在负电位下以双指数时间过程失活。对应于快门和慢门的弛豫的指数分量的时间常数与温度相关，Q(10) 值分别类似于3 和4。电流幅度随着温度的升高而增加，Q(10) 类似于1.6.3。的电压依赖性。随着温度的升高，两个门控过程转向更正的电位。对于快门和慢门，温度每升高 10 ℃，稳态开路概率 (P-o) 的半饱和电压 (V-1/2) 分别偏移约 23 和 34 mV。 4．在低 pH 值下，ClC-1 的电压依赖性发生逆转，电流通过单指数时程的超极化激活。 ClC-1 中的这种类型的门控类似于鱼雷 ClC-0 同系物的慢速门控，但在动力学和温度依赖性方面有所不同，负电势下的门控弛豫 Q(10) 类似于 5。低pH值下ClC-1电导的阿伦尼乌斯图在接近25℃时有明显的断点，在较低温度下具有较高的Q(10)值。5．在 ClC-0 和 ClC-1 中同时控制两个孔隙的慢门的弛豫温度敏感性和打开概率意味着 ClC-1 的慢门在机制上与 ClC-0 不同。
1. In the present work we investigated the dependence on temperature of the ionic conductance and gating of human muscle ClC-1 chloride channels, transiently expressed in human embryonic kidney (HEK 293) cells.2. At normal pH, ClC-1 currents deactivated at negative potentials with a double-exponential time course. The time constants of the exponential components, corresponding to the relaxations of the fast and slow gates, were temperature dependent with Q(10) values of similar to3 and similar to4, respectively. Current amplitude increased with increasing temperature with a Q(10) of similar to1.6.3. The voltage dependence of the. two gating processes was shifted towards more positive potentials with increasing temperature. The half-saturation voltage (V-1/2) of the steady-state open probability (P-o) was shifted by similar to 23 and similar to 34 mV per 10 degreesC increase in temperature, for the fast and slow gate, respectively.4. At low pH, thc voltage dependence of ClC-1 was reversed and currents were activated by hyperpolarisation with a single-exponential time course. This type of gating in ClC-1 resembled the slow gating of the Torpedo ClC-0 homologue, but differed with respect to its kinetics and temperature dependence, with a Q(10) of gating relaxations at negative potentials of similar to5. The Arrhenius plot of ClC-1 conductance at low pH had a clear break point at similar to 25 degreesC, with higher Q(10) values at lower temperatures.5. The temperature sensitivity of relaxation and open probability of the slow gate, which in both ClC-0 and ClC-1 controls two pores simultaneously, implies that the slow gating of ClC-1 is mechanistically different from that of ClC-0.