Fig. 6

Ca²⁺ release from WT and C3KO fibers in response to voltage clamp pulses. a Fluorescence transients recorded in a WT fiber in response to depolarization to −10, 0, 10, 20, 30, 40, and 50 mV. b Voltage dependence of the peak and steady-state values of the fluorescence transients in (a). Symbols are the experimental values, and lines are Boltzmann fittings to the data. The fitting parameters were: ΔF/F _max = 0.77, V _1/2 = 7 mV, k = 14 mV for peak values, and ΔF/F _max = 0.37, V _1/2 = 6 mV, k = 11 mV for steady-state values. c Ca²⁺-dependent fluorescence transients recorded in a C3KO fiber in response to the same depolarizations as in (a). The brown and green dots in (a) and (c) indicated the time at which the peak and steady ΔF/F values were measured. d Voltage dependence of the peak and steady-state values ΔF/F transients in (b). Symbols are the experimental values, and lines are Boltzmann fittings to the data. The fitting parameters were: ΔF/F _max = 0.61, V _1/2 = 2 mV, k = 13 mV for peak values, and ΔF/F _max = 0.28, V _1/2 = 0 mV, k = 10.3 mV for steady-state values