P2-purinergic receptors in vascular endothelial cells: from concept to reality.

ATP exerts at least 2 actions on arterial endothelial cells: it stimulates the release of endothelium-derived relaxing factor, a still unidentified vasodilator, and of prostacyclin, a potent inhibitor of platelet aggregation. A study of agonist specificity indicates that these responses are mediated by P2-purinergic receptors. We have now demonstrated that in these cells, the P2-receptors are coupled to a phospholipase C hydrolysing phosphatidylinositol-bisphosphate and that this coupling involves a pertussis toxin-sensitive GTP-binding regulatory protein.