[ATP-dependent transport of calcium in the myocardial sarcoplasmic reticulum during adaptation to muscular activities].

Two-fold increase in Ca2+-transport properties of Ca2+-pump was detected in myocardial sarcoplasmic reticulum (SR) during adaptation of animals to muscular activity (training by means of running on treadmill within 6 weeks, with gradual increase in duration and intensity). Besides, the rate of SR membranes phosphorylation via cAMP-dependent protein kinase was increased 1.3-fold. At the same time, cAMP-dependent phosphorylation accelerated 1.4-1.5-fold the rate of ATP-dependent transport of Ca2+ in myocardial SR of both control and trained animals. The data obtained suggest that increase in the Ca2+-pump activity and in the rate of phosphorylation of SR membranes via cAMP-dependent protein kinase are of importance for adaptation of animal heart muscle to elevated activity.