ClC-1 current deactivation is unaffected by formamide detubulation in paired experiments. Average voltage dependence of the relative contribution of slow (A), fast (B), and steady-state (C) components to ClC-1 deactivation in naive (filled circles) and detubulated (open squares) FDB fibers from 15–16-d-old mice in paired experiments. (D) Average voltage dependence of fast (squares) and slow (circles) time constants of ClC-1 deactivation in naive (filled symbol) and detubulated (open symbol) FDB fibers. Data mean ± SEM (n = 10 each control and detubulated fibers).