title: Inhibition of erythrocyte membrane Ca(2+)-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+,Mg(2+)-ATPase of hypertensive individuals in a concentration-dependent manner. About 50% inhibition was obtained at nifedipine concentrations greater than or equal to 300 microM. The extent of inhibition of the ATPase action was increased in the presence of calmodulin. Maximal inhibition at 400 microM was 76%. Furthermore, the activity of the partially trypsinized enzyme was inhibited by about 50% by 300 microM nifedipine. Similar results were obtained with membranes from normotensive individuals. These findings suggest that nifedipine could prevent Ca(2+)-pumping by the erythrocyte Ca2+,Mg(2+)-ATPase.
authors.affiliation: Department of Biochemistry, College of Medicine, University of Ibadan, Nigeria.
authors.forename: O O
authors.initials: OO
authors.lastname: Olorunsogo
authors.forename: O O
authors.initials: OO
authors.lastname: Onatola
authors.forename: S O
authors.initials: SO
authors.lastname: Lawal
authors.forename: E A
authors.initials: EA
authors.lastname: Bababunmi
authors.forename: A O
authors.initials: AO
authors.lastname: Falase
authors.forename: W G
authors.initials: WG
authors.lastname: Okunade
mesh_terms: D017301:Ca(2+) Mg(2+)-ATPase / Q000037:antagonists & inhibitors*; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D000252:Calcium-Transporting ATPases / Q000037:antagonists & inhibitors*; D004910:Erythrocyte Membrane / Q000201:enzymology; D006801:Humans; D006973:Hypertension / Q000201:enzymology*; D009543:Nifedipine / Q000494:pharmacology*
chemical_list: D002121:Calcium Channel Blockers; D017301:Ca(2+) Mg(2+)-ATPase; D000252:Calcium-Transporting ATPases; D009543:Nifedipine