[ATP-dependent transport of calcium in the myocardial sarcoplasmic reticulum during adaptation to muscular activities]. / ATP-zavisimyi transport kal'tsiia v sarkoplazmaticheskom retikulume miokarda pri adaptatsii k myshechnoi deiatel'nosti.

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.

[ATP-dependent calcium transport in the sarcoplasmic reticulum of the myocardium during vitamin E deficiency in the rat diet]. / ATP-zavisimyi transport kal'tsiia v sarkoplazmaticheskom retikulume miokarda pri nedostatke vitamina E v ratsione krys.

The vitamin E deficiency in the rat diet was studied for its effect on the activity of Ca2+-pump and phosphorylation of sarcoplasmic reticulum membrane fragments of myocardium. It is shown that under such an antioxidant deficiency ATP-dependent accumulation of calcium is 2.5 times as low, from 490 down to 190 nmol/mg of protein for 5 min. The administration of ionol, a synthetic antioxidant, to animals reduces the level of calcium accumulation, it is 1.8 times as high as that with vitamin E deficiency; cAMP-dependent phosphorylation of the sarcoplasmic reticulum preparation membranes of the test animal myocardium produces a 1.6-2.1 times increase in them of the ATP-dependent accumulation of calcium, the kinetics of Ca2+ accumulation is unchanged.