A) Left: Representative current traces from wildtype NavMs channels showing the first 0.1 s of 0.5 s activations from -180 mV holding potential recorded with the indicated extracellular cations. Right: Resulting current-voltage profiles profiles, where current magnitudes were normalized to the maximum inward current measured in the sodium condition.B) Left: Representative current traces from mutant channel E178D (as in A). Right: Resulting current-voltage profiles (error ± SEM; n = 6-9 for NavMs; n = 4-8 for E178D). 