ABSTRACT
The endothelium is an organ with a very active secreting activity (Figure 6.1). Endothelial cells release numerous vasoactive substances (i.e. nitic oxide; NO, endothelin; ET, prostacyclin and endothelium-derived hyperpolarising factor; EDHF) which regulate vascular smooth muscle and trafficking blood cells. In response to many stimuli, such as increased shear forces exerted by increased blood flow (Lüscher, 1990; Yanagisawa et al., 1988; Furchtgott, 1980) the endothelium releases NO, which is a potent vasodilator which also inhibits cellular growth and migration. In addition, NO possesses antiatherogenic and thromboresistant proprieties by preventing platelet aggregation and adhesion.
