Vasomotion of coronary arteries: From nitrates to nitric oxide

The vascular endothelium is a source of substances particularly nitric oxid e that act in a paracrine fashion either to contract or relax smooth muscle cells and this function is disturbed in atherosclerotic arteries. The endo thelium derived nitric oxide contribute in the basal vasomotor tone of epic ardial normal and atheromatous coronary coronary arteries, and of atheromat ous coronary stenoses in patients with stable angina. Nitrates, by acting i ndirectly to increase cGMP in smooth muscle cells, dilate most coronary ste noses and normal coronary segments, decrease left ventricular afterload and diastolic filling pressure and improve the distribution of coronary flow t o subendocardial zone. Large and small epicardial coronary vessels responde d differently to endothelium-dependent and independent vasodilators.