Acute effects of swimming aerobic exercise on contractility and intracellular calcium handling in isolated right ventricular cardiomyocytes

Aims: The acute adjustments on the contractile function and the intracellular calcium (Ca2+) handling in the cardiomyocytes of the right ventricle (RV) after an acute aerobic exercise session are not known. Our aim was to investigate the acute responses of the contractile function and the intracellular Ca2+ handling in isolated RV cardiomyocytes after a swimming exercise session. Methods: Ten-week-old female Wistar rats were randomly allocated into two groups: control (C; n = 5) and exercise (Ex; n = 7). It was performed a swimming exercise session for 30 min. with an overload of 4% relative to the body weight attached to the tail. The rats were sacrificed after the exercise session for the analysis of the RV contractile function parameters and the intracellular Ca2+ handling by the isolated cardiomyocyte technique. Results: Body and heart weights, as well as sarcomere length were similar between the groups. Also, it was not observed differences between the groups for RV cardiomyocyte contractile parameters. However, the systolic and diastolic intracellular Ca2+ concentration was significantly lower in the Ex group compared to C with maintenance of Ca2+ amplitude. Conclusion: An acute swimming aerobic exercise session promotes cardiomyocyte contractility maintenance even with systolic and diastolic intracellular Ca2+ concentration reduced in the RV cardiomyocytes, reflecting an improvement in the intracellular Ca2+ handling.