Cardiac Electrophysiological Alterations in Heart/Muscle-Specific Manganese-Superoxide Dismutase-Deficient Mice: Prevention by a Dietary Antioxidant Polyphenol

Figure 3

Action potentials recorded from left ventricular cells of control and H/M-Sod2 ^−/− mice and influences of chronic AP intake. (a) The membrane capacitance of ventricular cells isolated from each group of mice. Values are mean ± SEM, control, 𝑛=49; control + AP, 𝑛=33; H/M-Sod2 ^−/−, 𝑛=119; and H/M-Sod2 ^−/− + AP, 𝑛=72. (b) Representative action potential configurations of the ventricular myocytes in each group. (c) Action potential durations at 50% and 90% repolarization levels (APD₅₀ and APD₉₀) in the left ventricular myocytes of each group. Control, 𝑛=49; control + AP, 𝑛=32; H/M-Sod2 ^−/−, 𝑛=32; and H/M-Sod2 ^−/− + AP, 𝑛=41. Differences between groups, ***𝑃<0.001, **𝑃<0.01. (d) Resting membrane potentials in the left ventricular myocytes of each group. Data were obtained from ventricular cells not showing automaticity. Control, 𝑛=48, control + AP, 𝑛=23; H/M-Sod2 ^−/−, 𝑛=29, H/M-Sod2 ^−/− + AP, 𝑛=38. Differences between groups, ***𝑃<0.001. (e) Representative traces of a normal action potential (control group) and action potential showing abnormal automaticity (H/M-Sod2 ^−/− group). (f) The percentage of left ventricular cells showing automaticity. Differences between groups, ***𝑃<0.001.

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