Exercise training induced adaptations of calcium regulation in coronary artery smooth muscle cells

Sixteen Yucatan miniature swine were assigned to sedentary control or exercise training groups, and then pen confined or treadmill exercised for 16-20 weeks. Upon completion of the program, single smooth muscle cells (SMC) were enzymatically dispersed from the right coronary artery. Intracellular calcium regulation was studied in the SMC using microfluorometry techniques.SMC were assigned to one of three protocols: basal, short recovery and long recovery. SMC in the basal protocol were superfused with physiological saline solution (PSS) for 14 min, and then exposed to endothelin (ET). Short recovery protocol SMC were superfused with PSS for 9 min, depolarized with 80 Analysis of the physiological status of the animals and the intracellular free calcium concentration (CaConclusions based on the data were that exercise training attenuates the response of coronary artery SMC to ET. The mechanisms of SMC adaptation to achieve this response appear to involve changes in calcium regulation, rather than receptor-coupled events. It was suggested that exercise training may accelerate calcium leak from the SR under basal conditions, thus decreasing the amount of calcium sequestered in an ET-releasable pool. If human SMC respond similarly, exercise training may help prevent coronary artery spasm.