Figure 1.

Extracellular pH modifies Xenopus δβγ-ENaC currents. a, representative recordings of transmembrane currents (I_M) in oocytes expressing Xenopus δβγ-ENaC. The extracellular pH alters transient current kinetics of Xenopus δβγ-ENaC. Arrows indicate application of amiloride (a, 100 μm). b, current decays normalized to the initial peak values (I_{M, initial}) from recordings as depicted in a follow a two-phase decay consisting of a fast, initial decay as well as a slow, continuous current rundown. c, fractions of the fast, initial current decay (I_M decay_initial) are reduced with decreasing extracellular pH (one-way ANOVA, F = 20.31, p < 0.0001; Tukey's multiple comparisons test). d, amiloride-sensitive current fractions (ΔI_ami) derived from recordings as shown in a are markedly increased at pH 6.0 (Kruskal-Wallis test, p < 0.0001; Dunn's multiple comparisons test).