Conserved effect of dominant gain of function gating mutation inserted into zebrafish Kv3.3. A) F363L currents were evoked in oocytes by pulsing from a holding potential of -90 mV to voltages ranging from -80 to +60 mV in 10 mV increments. The bath contained 4 mM K+. The -10 mV trace is labeled for comparison to Fig. 6A. B) Normalized amplitudes of isochronal tail currents from F363L channels (red circles) have been plotted versus voltage. Data from wild type channels (black squares) are shown for comparison. Tail currents were recorded in an 89 mM Rb+ bath solution. The membrane was pulsed from -90 to +60 mV for 15 ms prior to repolarization to -90 mV. Data were fitted with a single Boltzmann function to obtain values for the midpoint voltage (V1/2) and slope factor, which were -21.4 ± 0.6 mV and 7.4 ± 0.2 mV, respectively (n = 8). C) Tail currents from wild type (gray trace) and F363L (red trace) channels were evoked in an 89 mM Rb+ bath solution by repolarizing from +40 to -90 mV. Tail current traces were fitted with a single exponential function (black curves). D) Box plot shows fitted values of τdeact at -90 mV. Mean τdeact values for wild type (n = 5) and F363L (n = 7) were 1.8 ± 0.1 ms (n = 5) and 23.3 ± 3.9 ms (n = 7), respectively. **, significantly different from wild type, p < 0.005 by Student's t-test.