Figure 7. Effect mNCX blockade on the increase in [Ca²⁺]_mito during repetitive stimulation at 5 Hz.

A. The 4mtD3cpv response (YFP, red; CFP, blue; ratio YFP/CFP, green) recorded at low illumination intensity to avoid bleaching of the probe in a WT fiber in the presence of 1 mM extracellular Ca²⁺. B. Response obtained in the fiber in the presence of 1 μM CGP37157 (CGP: a selective mitochondrial Na⁺/Ca²⁺ exchanger blocker). In the inset a comparison is shown of the recordings +/− CGP37157 on an expanded time scale, illustrating that in the presence of CGP37157 [Ca²⁺]_mito rises faster and reaches a higher final level. This is consistent with blockage of mitochondrial efflux via the mNCX during the stimulation period (10 s).