Figure 3.

Caffeine-induced Ca²⁺ release during the maintained phase of I_Ca. (A Top to Bottom) voltage protocol, confocal line-scan image, spatially averaged OG-5N fluorescence signal, and the simultaneously measured I_Ca. FPL (10 μM) was applied 10 s before depolarization, and caffeine was rapidly injected onto the cell 40 ms after the onset of depolarization. The smooth line in the Middle panel represents f_s. (B) Amount of SR Ca²⁺ released by I_Ca and caffeine quantified by integrating their respective release fluxes (f_r) transients (n = 6).