Formamide detubulation does not alter ClC-1 current magnitude or voltage dependence. Average voltage dependence of instantaneous (A) and steady-state (B) ClC-1 current from populations of naive (filled symbols) and formamide-treated (open symbols) FDB fibers from 15–16-d-old mice. Peak instantaneous current amplitude at −140 mV (C) and +60 mV (D) plotted against cell capacitance and fit with a straight line (slope reflecting average current density). Average cell capacitance (±SEM) and current magnitude (±SEM) for naive (filled symbols) and detubulated (open symbols) fibers are shown using square symbols. (E) Average voltage dependence of instantaneous ClC-1 current density of naive (filled symbols) and detubulated (open symbols) FDB fibers from 15–16-d-old mice. (F) Average voltage dependence of relative Po in naive (filled symbols) and detubulated (open symbols) FDB fibers from 15–16-d-old mice. Smooth curves through each Po-V dataset were generated using a modified Boltzmann equation (Eq. 3). Data are mean ± SEM of 20 and 18 control and detubulated fibers, respectively.