Fig. 6. Mitochondria-driven waves in cells with inhibited SR Ca²⁺ transport. (A) Confocal image time series showing a propagating depolarization wave evoked by addition of Ca²⁺ (50 µM CaCl₂) in a permeabilized H9c2 cell pretreated with Tg (2 µM) + Ry (200 µM) + C2 (40 µM). The fluorescence intensity of TMRE reflecting ΔΨ_m is shown using grayscale. Time courses of the F_TMRE changes are shown at three intracellular regions selected along the path of wave propagation. (B) Image time series showing a mitochondria-driven [Ca²⁺]_c wave in a permeabilized myotube pretreated with Tg + Ry + C2. Simultaneous confocal imaging of [Ca²⁺]_c (green) and [Ca²⁺]_m (red) was carried out using fluo3FF and compart mentalized rhod2 as described in Figure 5. In contrast to the results shown in Figure 1, addition of Ca²⁺ did not evoke SR-driven waves (images: 60, 100, 140 s and graphs). However, after >10 min lag time, a slowly propagating large amplitude [Ca²⁺]_c wave appeared, similarly to the mitochondrial wave shown in Figure 5. The right graph shows time courses (green) calculated for the marked subcellular regions.