EFFECTS OF A NEW CALCIUM-ANTAGONIST, CD-832, ON EXPERIMENTAL CORONARY-ARTERY SPASM IN MINIATURE PIGS

The effects of a new calcium antagonist, CD-832, on experimental coron ary artery spasms were studied in Gottingen miniature pigs. Pigs under went endothelial denudation at the left anterior descending coronary a rtery using a balloon catheter. Changes in the diameter of the denuded and nondenuded site in response to an intracoronary administration of serotonin (10 mug/kg) or histamine (10 mug/kg) were assessed quantita tively by selective coronary arteriography 1 week after endothelial de nudation. Percent reductions of the coronary artery diameter induced b y serotonin or histamine in the denuded site were significantly greate r than those in the nondenuded site (p < 0.01). Coronary artery spasm induced by serotonin or histamine in the denuded site was attenuated i n a dose-dependent manner by intravenous infusion of CD-832 (10 and 30 mug/kg/min) or nifedipine (1 and 3 mug/kg/min). The degrees of inhibi tion of coronary artery spasm by CD-832 were similar to those produced by nifedipine. CD-832 and nifedipine at the high dose caused comparab le increases in the basal coronary artery diameter. These results sugg est that CD-832 may be a useful drug for the treatment of coronary art ery spasm.