Modification of Ca2+ T-Sensitivity of Ca2+-Activated C1− Channel by Vasopressin and Cholera Toxin

Abstract

The apical membrane of renal epithelium (A6) had a Ca2+-activated, outwardly rectified chloride channel with the single channel conductance of 3 pS for outward current and 0,5 pS for inward current. The outward rectification was dependent on the cytosolic Ca concentration. Vasopressin (arginine vasopressin, AVP) and cholera toxin (CTX) increased the single channel conductance for inward current through an increase in the Ca2+-sensitivity about 100-fold. © 1993, PHYSIOLOGICAL SOCIETY OF JAPAN. All rights reserved.