Effects of MCI-154, a novel cardiotonic agent, on mean circulatory filling pressure in anesthetized dogs.

The effects of MCI-154, a novel cardiotonic agent, on mean circulatory filling pressure (an index of total body venous tone), total peripheral resistance and the heart were examined in anesthetized dogs. The bolus injection of MCI-154 (10-100 micrograms/kg i.v.) caused a dose-dependent decrease in mean circulatory filling pressure and resistance to venous return. MCI-154 also decreased the mean blood pressure and total peripheral resistance, and increased cardiac output and heart rate. Right atrial pressure was reduced only by the lowest dose (10 micrograms/kg i.v.) of MCI-154. These hemodynamic effects of MCI-154, except those on mean circulatory pressure and resistance to venous return, reached a maximum with 30 micrograms/kg of the drug. Nitroglycerin (50 micrograms/kg i.v.), a venodilator, decreased mean circulatory filling pressure, resistance to venous return, mean blood pressure and total peripheral resistance, and increased heart rate. However, unlike MCI-154, nitroglycerin did not alter cardiac output and right atrial pressure. These results suggest that the venodilator effect of MCI-154, as well as the positive inotropic and vasodilator effects, could potentially benefit patients with congestive heart failure.