Endothelial [Ca2+]iis an integrating signal for the vascular tone in rat aortae

Although various endothelium-dependent relaxing factors (endothelial autacoids) are released upon the elevation of endothelial cytosolic free Ca2+concentration (EC [Ca2+]i), the quantitative relationship between EC [Ca2+]iand vascular tone remains to be established. Moreover, whether the basal release of endothelial autacoids is modulated by basal EC [Ca2+]iis still unclear. We assessed these issues by using a novel method that allows simultaneous recording of EC [Ca2+]iand vascular displacement in dissected rat aortic segments.