title: Calmodulin antagonism and inhibition of erythrocyte plasma membrane Ca(2+)-pump by nifedipine, a calcium channel blocker.
abstract: Nifedipine, a 1,4-dihydropyridine Ca(2+)-channel blocker inhibits calmodulin-stimulated activity of erythrocyte plasma membrane (Ca(2+) + Mg2+)-ATPase. Its inhibition of the basal activity of the enzyme increases on pre-incubation with membranes. The maximum velocity, affinity for ATP and Ca(2+)-sensitivity of pump are reduced by micromolar amounts of the antihypertensive drug. These results suggest that 1,4-dihydropyridines may interact with calcium-binding proteins and calcium-dependent enzymes at their calcium-binding sites.
authors.affiliation: Biochemistry Department, College of Medicine, University of Ibadan, Nigeria.
authors.forename: O O
authors.initials: OO
authors.lastname: Olorunsogo
authors.forename: E A
authors.initials: EA
authors.lastname: Bababunmi
mesh_terms: D000818:Animals; D001681:Biological Assay; D017301:Ca(2+) Mg(2+)-ATPase / Q000187:drug effects*; D000252:Calcium-Transporting ATPases / Q000187:drug effects*; D002147:Calmodulin / Q000037:antagonists & inhibitors*; D002417:Cattle; D002462:Cell Membrane / Q000187:drug effects*; D004353:Drug Evaluation, Preclinical; D004912:Erythrocytes / Q000187:drug effects*; D009543:Nifedipine / Q000494:pharmacology*
chemical_list: D002147:Calmodulin; D017301:Ca(2+) Mg(2+)-ATPase; D000252:Calcium-Transporting ATPases; D009543:Nifedipine