Effects of N-(4-azo-endo-tricyclo[5.2.1.0.(2.6)]-decan-4-yl)-4-chloro-3-sulfamoylbenzamide (E614; tripamide) on vascular smooth muscles

1. In the guniea-pig mesenteric artery, E614 (less than 10(-6) g/ml) did not modify the membrane potential and resistance, but did suppress the spike evoked by outward current pulses in the presence of 3-5 mM TEA. This agent also suppressed the K-induced and noradrenaline-induced contractions. 2. In the mesenteric artery, E614 suppressed the amplitude of e.j.ps evoked by perivascular nerve stimulation. However, the facilitation process produced by repetitive stimulation was less affected. Miniature e.j.ps generated in the presence of 3 mM TEA were also suppressed by E614. 3. In the porcine coronary artery, E614 had little effect on the spike evoked by outward current pulses, in the presence of TEA. The mechanical response evoked by acetylcholine, excess [K]0 or electrical depolarization was hardly affected. 4. When the action of E614 was compared with that of diltiazem, a Ca channel blocker, this agent possesses properties which produce vasodilation of the peripheral vascular bed and thus may be considered as a hypotensive agent.