Endothelin and the renal vasculature.

The endothelin (ET) system comprises a family of three isopeptides (ET-1, ET-2, and ET-3)involved in diverse physiological and pathophysiological events. ET-1 is the major renal peptide that exerts its biological activity by binding to ET(A) and ET(B) receptors. Both ET(A) and ET(B) receptors are expressed by renal microvascular smooth muscle cells, where activation causes vasoconstriction. ET(B) receptors are also expressed by microvascular endothelial cells, where activation leads to vasodilator responses. ET-1 influences preglomerular and postglomerular microvascular tone and thus can significantly influence renal hemodynamics. Alteration of renal ET-1 synthesis and receptor expression has been reported in cardiovascular diseases, and could contribute to renal injury by altering renal microvascular reactivity. In this brief review, we will try to summarize what is known about ET control of renal microvascular function.