Effects of CD-832, a dihydropyridine derivative with a nitrate ester moiety, on rabbit femoral artery and vein

We investigated the effects of CD-832 ((4R)-(?)-2-(nicotinoyl-amino)ethyl 3-nitroxypropyl 1,4-dihydro-2,6-dimethyl-4,3-nitrophenyl, 3,5-pyridine dicarboxylate), a dihydropyridine derivative with a nitrate ester moiety, on contractile responses in rabbit femoral arteries and veins. CD-832 (10^?8 to 10^?6 M) and nifedipine inhibited the 64 mM KCl-induced and 10^?6 M norepinephrine-induced contractions of rabbit femoral arteries, while nitro compounds had no effect on the contractions. CD-832 (10^?8 to 10^?6 M) and nitro compounds inhibited the 10^?6 M norepinephrine-induced contractions in rabbit femoral veins, while other Ca²⁺ channel antagonists had little effect. The inhibitory effects of CD-832 (10^?7 M) on norepinephrine-induced contractions were antagonized by treatment with methylene blue (10^?5 M). These results indicate that CD-832 potently relaxes venous smooth muscle, and that it may be a useful agent for the treatment of angina pectoris.