Fig. 5

Simultaneous recording of cytosolic and mitochondrial Ca²⁺ transients. a A representative confocal image of FDB fiber expressing mt-YC3.6. Note the mitochondrial expression pattern of mt-YC3.6. b A representative image of an FDB fiber that is voltage-clamped through a glass pipette (from eight independent experiments). x-rhod-1 is delivered into the cytosol of the fiber through the pipette for recording of cytosolic Ca²⁺ transients. c Simultaneous recording of the dynamic changes of Ca²⁺ in both cytosol and mitochondria. Panel f ₃ is the fluorescence change of x-rhod-1 in cytosol during a brief pulse (20 ms). Panels f ₁ and f ₂ are the fluorescence changes of mt-YC3.6 at different emission wavelength. Panel f ₂ /f ₁ is the ratio of mt-YC3.6 images. d The time course of cytosolic x-rhod-1 (red trace) and mitochondrial mt-YC3.6 ratio (black trace) following a brief depolarization pulse (20 ms). e The time course of quantified Ca²⁺ transients in cytosol (red) and mitochondria (black). Note the similar time courses of cytosolic and mitochondrial Ca²⁺ transients