Panel A shows a scatter plot comparing calcium signal mass rates across three conditions: Control, RU360, and BKA. The horizontal axis represents different conditions, and the vertical axis represents calcium signal mass rate in arbitrary units (A. U.). Each dot represents an individual biological replicate, with large circles denoting per-animal means. The Control group shows higher calcium signal mass rates compared to RU360 and BKA groups. Panel A: Calcium signal mass rates under Control conditions, after inhibition of the mitochondrial calcium uniporter with RU360, and following blockade of the adenine nucleotide translocator with BKA. Panel B shows scatter plot of cyto-iATP signal mass rate (A. U.) across Control, RU360, and BKA groups. Panel C shows scatter plot of calcium signal mass rate (A. U.) under Control, RU360, and BKA conditions. Panel D shows scatter plot of mito-iATP signal mass rate (A. U.) comparing Control, RU360, and BKA treatments.
Mitochondrial Ca 2+ uptake and ANT-mediated ATP export are required for beat-to-beat metabolic signaling. (A and B) Summary data from SA node myocytes expressing the cytosolic ATP sensor (cyto-iATP). (A) Intracellular Ca2+ signal mass rates measured under control conditions, after inhibition of the MCU with RU360 (5 µM) and following blockade of the ANT with BKA (10 µM). (B) Corresponding cytosolic ATP signal mass rates obtained under the same conditions. (C and D) Summary data from parallel experiments in SA node myocytes expressing the mitochondrial ATP sensor (mito-iATP). (C) Intracellular Ca2+ signal mass rates. (D) Mitochondrial ATP signal mass rates. Data are presented as means ± SEM (N = 4 mice per group). P values are shown above comparisons. Large circles denote per-animal means; small circles indicate individual biological replicates. N represents the number of independent mice.