title: ETA and ETB receptors on vascular smooth muscle cells from mesenteric vessels of spontaneously hypertensive rats.
abstract: 1. To investigate the contribution of ETA and ETB receptors, calcium responses to the ETB agonist, IRL-1620, to endothelin-1 (ET-1) and to the ETA antagonist, BQ-123, were examined in primary cultured unpassaged vascular smooth muscle cells (VSMC) from mesenteric vessels of 3, 9 and 17 week old spontaneously hypertensive rats (SHR), Wistar and Wistar-Kyoto (WKY) rats using Fura-2 methodology. 2. IRL-1620 (10(-7) mol/L) and ET-1 (10(-9) mol/L) increased [Ca2+]i in all strains and ages. Responses to ET-1 and IRL-1620 were blunted in 17 week SHR. BQ-123 significantly reduced ET-1-stimulated [Ca2+]i. In endothelium-denuded mesenteric vessels, ET-1 and IRL-1620 induced significant [Ca2+]i responses. 3. Binding of ET-1 was significantly lower in mesenteric artery membranes from 17 week SHR compared to controls. 4. Thus, ETA and ETB receptors are present in rat mesenteric VSMC. In adult SHR, a reduced density of ET receptors results in decreased responses to IRL-1620 and to ET-1.
authors.affiliation: MRC Multidisciplinary Research Group on Hypertension, Clinical Research Institute of Montreal, University of Montreal, Quebec, Canada.
authors.forename: E L
authors.initials: EL
authors.lastname: Schiffrin
authors.forename: R
authors.initials: R
authors.lastname: Lariviere
authors.forename: R M
authors.initials: RM
authors.lastname: Touyz
mesh_terms: D000818:Animals; D065128:Endothelin Receptor Antagonists; D016232:Endothelins / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000378:metabolism / Q000473:pathology; D006973:Hypertension / Q000378:metabolism* / Q000473:pathology; D066298:In Vitro Techniques; D008297:Male; D008638:Mesenteric Arteries / Q000166:cytology / Q000378:metabolism* / Q000473:pathology; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D010446:Peptide Fragments / Q000494:pharmacology; D010456:Peptides, Cyclic / Q000494:pharmacology; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D017208:Rats, Wistar; D017466:Receptors, Endothelin / Q000378:metabolism*
chemical_list: D065128:Endothelin Receptor Antagonists; D016232:Endothelins; D010446:Peptide Fragments; D010456:Peptides, Cyclic; D017466:Receptors, Endothelin; C074308:sovateltide; C072247:cyclo(Trp-Asp-Pro-Val-Leu)