Endothelin receptor subtype B mediates synthesis of nitric oxide by cultured bovine endothelial cells.

Abstract

Endothelins (ET) produce endothelium-dependent vasodilation through nitric oxide (NO) synthesis. The present study was designed to elucidate the cellular mechanism by which ET induces synthesis and release of endothelium-derived NO by cultured bovine endothelial cells (EC). Binding studies revealed that bovine EC membrane had the binding sites of a novel agonist (BQ3020) for non-isopeptide-selective receptor subtype (ETB). Affinity labeling studies showed a major labeled band with the apparent molecular mass of 50 kD. Northern blot analysis demonstrated the expression of mRNA for ETB receptor. BQ3020 rapidly and dose dependently induced formation of inositol-1,4,5-triphosphate and increased intracellular Ca2+ concentrations in fura-2-loaded cells. Concomitantly, BQ3020 dose dependently stimulated production of both nitrate/nitrite (NOx) and cyclic GMP, a highly significant correlation existed between NOx and cGMP production.The stimulatory effect on NOx and cGMP production by ETB agonist was inhibited by NO synthase inhibitor monomethyl-Larginine; this effect was reversed by coaddition of L-arginine, but not D-arginine. NOx and cGMP production stimulated by BQ3020 was inhibited by pretreatment with pertussis toxin.ETB agonist-induced NOx production was blocked by a calmodulin inhibitor and an intracellular Ca2" chelator, but not by an extracellular Ca2" chelator or a Ca2+ channel blocker. These data suggest that endothelins stimulate ETB receptor-mediated phosphoinositide breakdown via pertussis toxin-sensitive Gprotein(s), which triggers release of intracellular Ca2+, thereby activating Ca2+/calmodulin-dependent NO synthase in EC. (J. Clin. Invest. 1993. 91:1367-1373.) Key words: endothelin * receptor subtype B * nitric oxide -Ca2`/calmodulinendothelial cell

Biliary cyst fluid from common bile duct–ligated rats stimulates endothelial nitric oxide synthase in pulmonary artery endothelial cells: A potential role in hepatopulmonary syndrome

“…The effect on NOS activity described here is similar to that described previously for ET-1 in cultured endothelial cells and has been established to occur through the ET B receptor. 9 The effect on eNOS mRNA and protein levels is similar to what we have observed for ET-1 in BPAECs previously 6 and is also similar in magnitude to the increase in lung eNOS levels seen in vivo in animals with HPS. 4 The alterations are consistent with an effect on eNOS expression.…”

“…When cells reached 70% confluence, the media was changed and cells were stimulated with biliary cyst fluid at various dilution (1: 1,000, 1:100, or 1:10) for 24 hours for Western blotting, 12 hours for Northern blotting, or 1 hour for nitric oxide synthase (NOS) activity. The times for analysis were based on previously published work in BPAECs and other cultured vascular endothelial cells that demonstrate that maximal changes in eNOS messenger RNA (mRNA) and protein levels 6 or in NOS activity 9 after ET-1 stimulation occur near the chosen measurement time points. Prior to cell lysis, cell culture media was obtained from each well and stored at Ϫ80°C for NO measurement.…”

Reversing gene expression in cardiovascular target organs following chronic depression of the paraventricular nucleus of hypothalamus and rostral ventrolateral medulla in spontaneous hypertensive rats

“…In the vasculature, Ednra receptor mediates vasoconstriction (Haynes & Webb, 1993;Janakidevi et al, 1992) while the Ednrb receptors mediate vasodilatation through the release of nitric oxide and/or prostacyclin (Hirata et al, 1993;Filep et al, 1991;Schneider et al, 2007).…”

Role of Notch Signaling in Pulmonary Hypertension

“…ET--1 mediates its proliferative functions in PASMCs via binding to ET--A and ET--B receptors (ETRA, ETRB) [33]. As ETRB on endothelial cells is involved in release of vasodilators [34], hence, selective inhibition of ETRA has moved into focus in therapeutic targeting of ET--1 pathway in PH [33].…”