Inhibition of erythrocyte membrane Ca2+ -pumping ATPase of hypertensive, humans by nifedipine, a calcium entry blocker

Abstract

Nifedipine, a 1,4-dihydropyridine antihypertensive drug, inhibited the basal activity of erythrocyte Ca2+, Mg2+ -ATPase of hypertensive individuals in a concentration-dependent manner. About 50% inhibition was obtained at nifedipine concentrations ≥ 300 µm. The extent of inhibition of the ATPase action was increased in the presence of calmodulin. Maximal inhibition at 400 µm was 76%. Furthermore, the activity of the partially trypsinized enzyme was inhibited by about 50% by 300 µm nifedipine. Similar results were obtained with membranes from normotensive individuals. These findings suggest that nifedipine could prevent Ca2+ -pumping by the erythrocyte Ca2+, Mg2+ -ATPase.