Figure 1

Insulin increases mitochondrial Ca²⁺through an InsP ₃ R dependent pathway. A) Confocal images of insulin-induced mitochondrial Ca²⁺ signal captured at the indicated times in cardiomyocytes loaded with Rhod-FF 5,4 μM. B-E) Representative measures of fluorescence-associated insulin-induced mitochondrial Ca²⁺ signals in cardiomyocytes pre-treated with (gray line) or without (Ctrl, black line) the respective inhibitors for 30 min. Insulin (100 nM) was added at 100 s. B) Ruthenium Red (Ru), 10 μM; C) xestospongin C (XeC), 100 μM; D) U73122 (U73), 10 μM and E) Ryanodine (Rya), 50 μM. F) Area under the curve of insulin-induced mitochondrial Ca²⁺ signals of control, Ru, XeC, U73 and Rya pre-treated cardiomyocytes after insulin stimulation between 100 and 300 s. The results are representative of 3 independent experiments (N = 3), where 10-20 cells were analysed. Data are expressed as mean ± SEM, *P < 0.05 vs. Ctrl. G) Measurement of insulin-induced mitochondrial Ca²⁺ signal in cardiomyocytes transfected with a siRNA control (black line) or a siRNA against MCU (gray line). Insulin (100 nM) was added at 100 s. H) Area under the curve of insulin-induced mitochondrial Ca²⁺ signals of control and siRNA-mCU treated cardiomyocytes. The results are representative of 3 independent experiments (N = 3), where 10-20 cells were analysed. Data are expressed as mean ± SEM, **P < 0.01 vs. siRNA Ctrl.