Figure 7.

Replacing extracellular Ca²⁺with Ba²⁺enhances Cx30-mediated inhibition of ENaC.A and B, representative whole-cell current traces recorded in oocytes expressing ENaC alone (left panels) or coexpressing ENaC with Cx30 (right panels) incubated for 48 h in standard incubation solution containing 1.8 mM Ca²⁺ ([Ca²⁺]_o = 1.8 mM; A) or in incubation solution in which 1.8 mM Ca²⁺ was replaced with 1.8 mM Ba²⁺ ([Ba²⁺]_o = 1.8 mM; B). Application of amiloride (Ami, 2 μM) is indicated by filled bars. Dashed lines indicate zero current level. C, ΔI_Ami values from similar experiments as shown in the representative traces A and B. Mean ± SEM and data points for individual oocytes are shown; ∗∗∗p < 0.001; n.s., not significant; Kruskall–Wallis with Dunn’s post hoc test (n = 20, N = 2). D, relative inhibitory effect of Cx30 on ENaC calculated from the data shown in C essentially as described in Figure 3. Mean ± SEM and data points for individual oocytes are shown; ∗∗∗p < 0.001; Mann–Whitney test.