Krafte D S, Kass R S
Department of Physiology, University of Rochester, New York 14642.
J Gen Physiol. 1988 May;91(5):641-57. doi: 10.1085/jgp.91.5.641.
We have investigated the effects of H ions on (L-type) Ca channel current in isolated ventricular cells. We find that the current amplitude is enhanced in solutions that are alkaline relative to pH 7.4 and reduced in solutions acidic to this pH. We measured pH0-induced shifts in channel gating and analyzed our results in terms of surface potential theory. The shifts are well described by changes in surface potential caused by the binding of H ions to negative charges on the cell surface. The theory predicts a pK of 5.8 for this binding. Gating shifts alone cannot explain all of our observations on modulation of current amplitude. Our results suggest that an additional mechanism contributes to modification of the current amplitude.
我们研究了氢离子对分离的心室肌细胞中（L型）钙通道电流的影响。我们发现，相对于pH 7.4呈碱性的溶液中电流幅度增强，而酸性溶液中电流幅度降低。我们测量了pH0诱导的通道门控变化，并根据表面电位理论分析了我们的结果。这些变化可以很好地用氢离子与细胞表面负电荷结合引起的表面电位变化来描述。该理论预测这种结合的pK值为5.8。仅门控变化无法解释我们所有关于电流幅度调制的观察结果。我们的结果表明，还有一种额外的机制参与了电流幅度的调节。
