Original Scientific Paper Myocardial sarcoplasmic reticulum Ca2+ ATPase function is increased by aerobic interval training

Objective Reduced activity of the sarcoplasmic reticulum Ca2+ ATPase-2a (SERCA-2a) contributes to myocardial dysfunction. Exercise training improves myocardial Ca2+-handling, but SERCA-2a function is uncertain. We assessed SERCA-2a activity after exercise training. Methods SERCA-2a function was assessed by sarcoplasmic reticulum Ca2+ uptake in cardiomyocytes with other Ca2+ uptake mechanisms blocked, in mice after aerobic interval training versus sedentary controls. Results We established protocols to assess SERCA-2a function, and show that aerobic interval training increases the maximal rate of Ca2+ uptake by 30%. This is at least partly explained by reduced phospholamban-to-SERCA-2a ratio. Conclusion Aerobic interval training improves myocardial SERCA-2a performance, explaining at least partly wh