Inhibition of nisoldipine on bovine mesenteric arteries and veins and on human peripheral veins.

The inhibiting effect of the calcium channel blocker nisoldipine (CAS 63675-72-9, Baymycard, Syscor) on potassium-induced contraction on bovine mesenteric veins and arteries and human peripheral veins was investigated. Nisoldipine inhibited the contraction on bovine mesenteric veins at a significantly lower concentration (1 x 10(-10) mol/l) than nifedipine and glyceryl trinitrate (GTN) (1 x 10(-7) mol/l). When the preparations were preincubated with the drugs, nisoldipine reduced the contraction, measured as area under the curve (AUC), with 47 +/- 8% (mean +/- SEM) and nifedipine with 29 +/- 13% in veins. It was necessary to use an inconsiderably higher concentration of nisoldipine to relax bovine mesenteric arteries contracted by potassium. Preincubation of these arteries with nisoldipine (1 x 10(-7) mol/l) reduced contraction measured as AUC by 46 +/- 10% and preincubation with nifedipine (1 x 10(-7) mol/l) by 77 +/- 3%. Nisoldipine also caused a marked relaxation in human saphenous veins. The introduction of nisoldipine (1 x 10(-8) mol/l) after potassium-induced contraction caused 54 +/- 8% relaxation.