The reversal potentials in the wild-type (WT), W1716E, F1764R, and W1716E/F1764R (WEFR) mutant channels. (A) The representative current–voltage plots. The oocytes expressing each of the four different channels were bathed in ND-96. The oocytes were held at −120 mV and stepped to a test pulse of −120 to +50 mV for 100 ms, and then returned to −120 mV. The pulse protocols were repeated every 3 s, and the peak current at each test pulse is normalized to the maximal current elicited and plotted against the test pulse voltage to give the current–voltage plots. (B) The averaged reversal potentials for the four different channels in A (n = 5–15).