Figure 2. Leak is associated to reactive oxygen species in cardiomyocytes.

(A) SR Ca²⁺ leak in WT and NOS1^{−/ −}at 23°C or 37°C [at matched SR Ca²⁺ load ≈ 75 μmol/L] (Student's t-test). (B) ROS in WT and NOS1^{−/ −}at 23°C or 37°C (Student's t-test), as measured by epifluorescence of H₂DCF 5 minutes after the initial reading. (C) Dependence of SR Ca²⁺ leak with temperature in WT or NOS1^−/− cardiomyocytes in the absence or the presence of 1mmol/L Tempol [at matched SR Ca²⁺ load ≈ 75 μmol/L] (* p < 0.05 and ** p < 0.01 ( −-treated WT; . †††† (-) Tempol vs. +Tempol p < 0.0001 (-)Tempol vs. +Tempol-treated NOS1^−/− cardiomyocytes; Two-way ANOVA). (D) SR Ca²⁺ load-leak relationship in WT or NOS1^−/− cardiomyocytes, non-treated and Tempol-treated at 23°C (** p < 0.01 WT (-)Tempol vs. WT +Tempol and †† p < 0.01 NOS1^−/− (-)Tempol vs. NOS1^−/− +Tempol). (E) At 37°C (*** p <0.0001 WT (-)Tempol vs. WT +Tempol and ††† p <0.001 NOS1^−/− (-)Tempol vs. NOS1^−/− +Tempol; exponential growth fitting.