Fig. 3.

Epithelial Na⁺ channel (ENaC) Na⁺ self-inhibition response. Current traces illustrate the Na⁺ self-inhibition response assessed in Xenopus oocytes expressing wild-type (WT) human ENaC (left) or the γL511Q mutant (right). Oocytes were initially bathed in a solution containing 1 mM Na and 109 mM N-methyl-d-glucamine. After a rapid transition to a 110 mM Na bath, a rapid increase in inward Na⁺ current (I; downward deflection) was followed by a slow reduction in current, reflecting Na⁺ self-inhibition. The Na⁺ self-inhibition response in oocytes expressing the γL511Q mutant was markedly dampened. [Modified from Chen et al. (38), with permission.]