[Role of endothelial nitric oxide in the regulation of arterial tone].

Nitric oxide (NO) is the main agent of communication between the endothelium and the smooth muscle, involved in vasodilatation. Its vasodilator action requires prior tonic contraction of smooth muscle cells, related to vasoactive agents such as catecholamines or angiotensin II-induced centripetal communications and pharmaco-mechanical coupling. In physiological conditions, NO is liberated following constitutive endothelial NO synthase activity in response to shear stress generated by the dynamics of blood on the arterial wall. Endothelial dysfunction modifying NO production is implicated in different cardiovascular diseases such as hypertension, congestive heart failure and atherosclerosis.