title: Effects of dihydropyridine calcium antagonists on rabbit renal Na,K-ATPase activity in vitro.
abstract: Dihydropyridines are reported to have a stimulatory effect on vascular smooth muscle Na,K-ATPase activity in vitro. We studied the effects of the dihydropyridine calcium antagonists nimodipine, nitrendipine, nisoldipine, niludipine, nifedipine and felodipine (10(-5) M) on purified Na,K-ATPase isolated from rabbit kidney outer medulla. We were unable to detect an effect of the drugs on the enzyme activity, either under optimal or suboptimal substrate conditions. Likewise, Na,K-ATPase activity, partly inhibited by the addition of ouabain (10(-6) M), Ca2+ (10(-3) M) or arachidonic acid (4 x 10(-5) M), was not influenced by the dihydropyridines. The absence of a stimulatory effect of dihydropyridines on renal Na,K-ATPase is in agreement with the known diuretic and natriuretic effects of the drugs in normotensive and hypertensive men.
authors.affiliation: Department of Biochemistry, University of Nijmegen, The Netherlands.
authors.forename: H J
authors.initials: HJ
authors.lastname: Kloke
authors.forename: H G
authors.initials: HG
authors.lastname: Swarts
authors.forename: H E
authors.initials: HE
authors.lastname: Sluiter
authors.forename: F T
authors.initials: FT
authors.lastname: Huysmans
authors.forename: J J
authors.initials: JJ
authors.lastname: De Pont
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D004095:Dihydropyridines / Q000494:pharmacology*; D066298:In Vitro Techniques; D007668:Kidney / Q000187:drug effects / Q000201:enzymology*; D008566:Membranes / Q000187:drug effects / Q000201:enzymology; D009131:Muscle, Smooth, Vascular / Q000187:drug effects; D011817:Rabbits; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*
chemical_list: D002121:Calcium Channel Blockers; D004095:Dihydropyridines; D000255:Adenosine Triphosphate; D000254:Sodium-Potassium-Exchanging ATPase