Figure 2. The stimulatory effect of the αW493R mutation is independent of Na⁺ feedback inhibition.

αβγENaC (wt)- and α_W493RβγENaC (αW493R)-expressing oocytes were incubated in parallel in high Na⁺ and low Na⁺ solution. A, representative whole-cell current traces of individual oocytes at a holding potential of −60 mV. Amiloride (2 μm) was present in the bath as indicated by the black bars. B, summary of similar experiments as shown in A performed in oocytes from 3 different batches. C, to illustrate the relative effect of Na⁺ feedback inhibition on wild-type and mutant ENaC the individual ΔI_ami values summarized in B were normalized for each batch to the mean ΔI_ami value measured in the corresponding group of low Na⁺ oocytes. Numbers in or above columns indicate individual number of oocytes, N indicates number of different batches of oocytes. **P < 0.01, ***P < 0.001.