Comparative study of direct coronary vascular responses to diltiazem, adrenergic beta-blockers and other vasodilators in isolated, perfused dog and monkey coronary arteries.

The cannula-inserting method was used to examine the vascular responses of the isolated, perfused dog and monkey coronary arteries to a calcium antagonist (diltiazem), adrenergic beta-blockers (propranolol and pindolol), an antianginal drug (nicorandil) and vasodilators (hydralazine and papaverine). Propranolol and pindolol constricted the dog and monkey coronary arteries dose-dependently. Without any precontraction, hydralazine produced a biphasic response--a vasodilatation followed by a vasoconstriction--in the dog coronary artery, although it produced only a vasodilatation in the monkey coronary artery. Nicorandil and diltiazem dilated the uncontracted dog and monkey coronary arteries dose-dependently. The rank order of drug potency for inducing vasodilatation was diltiazem greater than nicorandil greater than hydralazine in both coronary arteries. These results indicate that the cannula-inserting method is useful to investigate the responses of the large epicardial dog and monkey coronary arteries to vasodilating drugs.