Effects of dihydropyridine calcium antagonists on rabbit renal Na,K-ATPase activity in vitro.
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.
Kloke
H J
HJ
Department of Biochemistry, University of Nijmegen, The Netherlands.
Swarts
H G
HG
Sluiter
H E
HE
Huysmans
F T
FT
De Pont
J J
JJ
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*
D002121:Calcium Channel Blockers; D004095:Dihydropyridines; D000255:Adenosine Triphosphate; D000254:Sodium-Potassium-Exchanging ATPase