CARDIOVASCULAR EFFECTS OF OPC-13340, A POTENT, LONG-ACTING 1,4-DIHYDROPYRIDINE CALCIUM-CHANNEL BLOCKER, IN DOGS

The cardiovascular effects of OPC-13340, a newly developed 1,4-dihydro pyridine calcium channel blocker, were examined in several canine prep arations. In conscious normotensive and DOCA-salt hypertensive dogs, O PC-13340, at doses of 10 to 30 mug/kg, i.v., and 0.3 to 3 mg/kg, p.o., exerted an hypotensive action in a dose-dependent manner. The hypoten sive action of OPC-13340 was longer lasting and more potent than that of nicardipine and nifedipine. In conscious, normotensive instrumented dogs, OPC-13340, at doses of 1 and 3 mg/kg, p.o., dose-dependently de creased total peripheral resistance and mean blood pressure and increa sed heart rate, cardiac output and left ventricular contractility. In anesthetized open-chest dogs, OPC-13340, at doses of 1 to 30 mug/kg, i .v., increased coronary blood flow and decreased mean blood pressure, heart rate, coronary vascular resistance, arteriovenous oxygen differe nce and myocardial oxygen consumption. In contrast to OPC-13340, nicar dipine did not change the myocardial oxygen consumption. From these re sults it was concluded that OPC-13340 lowered blood pressure and impro ved coronary circulation in dogs and that the duration of these action s was longer lasting than that of nifedipine and nicardipine. These ac tions of OPC-13340 may be useful in the treatment of hypertension and angina pectoris.