Calcium-Activated Chloride Channels: The Role of Potassium Ions.

Using the patch–clamp method in the whole-cell configuration, it was shown that external potassium ions play an important role in the regulation of calcium-activated chloride currents. A clear dependence of the amplitude of chloride currents on changes in the concentration of external potassium is shown. Changes in the concentration of sodium, magnesium, and calcium ions from outside the membrane have no significant effect, unlike the outside potassium ions. The effect of potassium on the amplitudes of chloride currents is significantly greater than the effect it has on other cell ionic currents—sodium, potassium, cation. There is reason to believe that a change in the amplitudes of chloride currents contributes to the pathophysiological processes characteristic of hypokalemia and hyperkalemia. [ABSTRACT FROM AUTHOR]