Endothelial control of vascular tone by nitric oxide and gap junctions: a haemodynamic perspective.

Local haemodynamic forces acting on the endothelium modulate vascular tone through mechanisms that normalize intimal shear stress. This flow-dependent diameter response contributes to the optimization of circulatory function and is mediated via shear stress-induced release of NO, vasodilator prostanoids and a putative endothelium-derived hyperpolarizing factor or EDHF. There is growing evidence that NO/prostanoid independent relaxations involve direct heterocellular signalling between endothelial and smooth muscle cells via gap junctions.