Figure 4.

Carbenoxolone significantly reduces the inhibitory effect of Cx30 on ENaC.A and B, representative whole-cell current traces recorded in oocytes expressing ENaC without (left traces) or with Cx30 (right traces). After cRNA injection oocytes were incubated for 48 h in incubation solution with carbenoxolone (100 μM, A) or without (mock incubation, B). Carbenoxolone was absent from the bath solution during the whole-cell current recordings. Application of amiloride (Ami, 2 μM) and removal of divalent cations from the bath solution for 60 s (Ca²⁺ Mg²⁺-Removal) are indicated by corresponding bars. Dashed lines indicate zero current level. C, ΔI_Ami values from similar experiments as shown in the representative traces in 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 = 44, N = 4). 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.