Modulation of Endothelin Release by Vasoactive Peptides Localised in Human Umbilical Vein Endothelial Cells

Human umbilical vessels are remarkable in lacking innervation; thus the role of the vascular endothelium is likely to be of prime importance in the local control of vascular tone. The vasoactive mediators arginine vasopressin (AVP), neuropeptide Y (NPY), vasoactive intestinal polypeptide (VIP), calcitonin gene-related peptide (CGRP) and substance P (SP) have been localised in the endothelial cells of human umbilical vessels but as yet no physiological roles have been assigned to their presence in this vessel. The effect of these vasoactive substances on the basal and thrombin-stimulated (10U/ml) release of the potent vasoconstrictor peptide endothelin-1 (ET-1) from cultured human umbilical vein endothelial cells was studied using an enzyme-linked immunosorbent assay. AVP (10−5 - 10−7M) increased basal and thrombin-stimulated ET-1 release. NPY (10dM) increased basal ET-1 release but did not significantly alter thrombin stimulated release. VIP (10−6 - 10−7M) exerted no significant effect on ET-1 release. CG...