[Effect of nicorandil on coronary circulation in ischemic region]

To clarify the role of nicorandil (Nic) in relieving myocardial ischemia, the effects of Nic in canine models of coronary arterial stenosis were studied. During stenosis of the anterior descending coronary artery by an external micrometer constrictor, intracoronary infusion of Nic 1, 5 micrograms/(kg.min) increased coronary blood flow and decreased distal coronary pressure, total coronary arterial resistance and small coronary arterial resistance; but did not affect mean aortic pressure, heart rate and large coronary arterial resistance. Whole blood viscosity, plasma viscosity and hematocrit in coronary vein after intracoronary infusion of Nic were reduced. The results intravenous infusion of Nic were similar to those of intracoronary infusion. These results indicate that Nic is capable of increasing coronary blood flow, alleviating myocardial ischemia due to direct dilatation of coronary artery and reduction of blood viscosity in ischemic region.