Different types of
ATP-sensitive K+ (K(
ATP)) channels have been identified in cardiomyocytes, vascular smooth muscle cells, pancreatic beta-cells, neurons and mitochondria. Years before the discovery of the K(
ATP) channel in cardiomyocytes, pharmacological openers of this channel had been developed for the treatment of
angina pectoris and
hypertension. The K(
ATP) channel plays an important role not only in coronary blood flow regulation but also in protection of cardiovascular cells from
ischemia/reperfusion injury. In animal models of
myocardial ischemia/reperfusion, activation of the mitochondrial K(
ATP) channels by their pharmacological openers has been shown to attenuate endothelial dysfunction and to reduce myocardial
necrosis. Conversely, blockade of the K(
ATP) channel aggravates microvascular
necrosis and the
no-reflow phenomenon after
ischemia/reperfusion, resulting in augmentation of post-
infarct ventricular dysfunction. Recent clinical studies have shown that a combination of coronary reperfusion
therapy and infusion of
nicorandil, a hybrid of K(
ATP) channel opener and
nitrate, improved left ventricular function in patients with acute
myocardial infarction. Furthermore, chronic treatment with
nicorandil has been shown to significantly improve prognosis of patients with high-risk
stable angina pectoris. Both of these clinical benefits cannot be attributed to the
nitrate property of
nicorandil. However, a recent basic investigation has suggested that the protective function of K(
ATP) channel openers is compromised by concurrent
hypercholesterolemia and administration of sulfonylureas for
diabetes mellitus. These interferences in the beneficial action of K(
ATP) channel openers by concurrent illness and pharmacological agents need to be further investigated to allow a more effective use of K(
ATP) channel openers in patients with
coronary artery diseases.