Total charge movement per channel. The relation between gating charge displacement and the voltage sensitivity of activation.
Total charge movement per channel. The relation between gating charge displacement and the voltage sensitivity of activation.
复制标题
每通道总充电移动。门控电荷位移与激活的电压灵敏度之间的关系。
DOI：
10.1085/jgp.109.1.27
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发表时间：
1997-01
影响因子：
3.8
通讯作者：
Bezanilla, F
中科院分区：
文献类型：
--
作者：
Sigg, D;Bezanilla, F
离子通道电导的电压依赖性的一个量度是在激活期间移动的门控电荷的量，反之亦然。极限斜率法是由Almers（Almers，W. 1978.生理学、生物化学、药理学修订版82：96-190），利用了电荷移动和电压灵敏度的关系，产生了单通道选通电荷位移范围的下限。在实践中，由于要求在非常低的打开概率下测量激活的对数电压灵敏度，因此该技术受到低实验分辨率的困扰。此外，线性序列模型，原来的理论是有限的，需要扩大，以适应复杂的机制，可用于激活通道。在这篇文章中，我们通过建立平均激活电荷位移（激活的电压灵敏度的测量）和门控电荷位移（门控电流的积分）之间的关系来完善理论。我们证明，记录的平衡门控电荷位移作为一个辅助的限制斜率技术大大提高了准确性的条件下，平均激活电荷位移和总门控电荷位移与电压的曲线可以叠加。我们探讨了各种各样的通道模型，其中包括那些具有连续密度的状态，非顺序激活途径，亚电导状态的这种关系。我们介绍了新的标准，适当使用的限制斜率的程序，并提供了一个实际的例子，适用于低分辨率的模拟数据的理论。
One measure of the voltage dependence of ion channel conductance is the amount of gating charge that moves during activation and vice versa. The limiting slope method, introduced by Almers (Almers, W. 1978. Rev. Physiol. Biochem. Pharmacol. 82:96–190), exploits the relationship of charge movement and voltage sensitivity, yielding a lower limit to the range of single channel gating charge displacement. In practice, the technique is plagued by low experimental resolution due to the requirement that the logarithmic voltage sensitivity of activation be measured at very low probabilities of opening. In addition, the linear sequential models to which the original theory was restricted needed to be expanded to accommodate the complexity of mechanisms available for the activation of channels. In this communication, we refine the theory by developing a relationship between the mean activation charge displacement (a measure of the voltage sensitivity of activation) and the gating charge displacement (the integral of gating current). We demonstrate that recording the equilibrium gating charge displacement as an adjunct to the limiting slope technique greatly improves accuracy under conditions where the plots of mean activation charge displacement and gross gating charge displacement versus voltage can be superimposed. We explore this relationship for a wide variety of channel models, which include those having a continuous density of states, nonsequential activation pathways, and subconductance states. We introduce new criteria for the appropriate use of the limiting slope procedure and provide a practical example of the theory applied to low resolution simulation data.