Fig. 1

Ca²⁺ transients elicited by single action potentials in FDB fibers from WT and C3KO mice. a Representative single-sweep fluorescence transient recorded from a WT fiber. c The action potential triggering the fluorescence transient in (a). b, d The corresponding representative fluorescence transient and action potential recorded from a C3KO fiber. The peaks of the ΔF/F transients are 0.63 and 0.55 for the control and C3KO fibers, respectively. The fluorescence transients in (a) and (b) are shown normalized and superimposed in the inset of (b). The inset in (d) shows the superimposed normalized action potentials in (b) and (d. e, f The calculated Ca²⁺ fluxes (green traces, in μM/ms) underlying the fluorescence transients in (a) and (b), respectively. The black traces in (e) and (f) are the predicted ΔF/F transients (left axis), and the blue and red traces in (e) and (f) are the experimental ΔF/F transients in WT and C3KO, respectively. The horizontal lines represent zero ΔF/F for (a) and (c) (and inset in (c)) and −90 mV for (b) and (d)