title: Characterization of endothelin receptors mediating contraction and relaxation in rabbit saphenous artery and vein.
abstract: The endothelin receptors in rabbit isolated rings of saphenous artery and saphenous vein have been characterized using endothelin-1, endothelin-2, endothelin-3, sarafotoxin S6c, and BQ123. Although artery rings were more sensitive than those from vein to the contractile action of phenylephrine, endothelin-1 was about three times more potent as a contractile agonist on vein than on artery. In rings precontracted with phenylephrine, carbachol was 10 times more potent in vein than in artery rings to induce endothelium-dependent relaxation. However, in rings precontracted to a similar tone by endothelin-1, the relaxation elicited by carbachol was reduced in the vein but remained unchanged in the artery. In endothelium-denuded saphenous artery, endothelin-1 and endothelin-2 elicited contraction with equal potency, whereas endothelin-3 and sarafotoxin S6c were weak agonists. In saphenous vein, the rank order of sensitivity was sarafotoxin S6c > endothelin-2 > or = endothelin-1 = endothelin-3, whereas sarafotoxin S6c and, to a lesser extent, endothelin-3 act as partial agonists. The ETA receptor antagonist BQ123 shifted, to the right, the concentration-response curves of endothelin-1 on endothelium-denuded saphenous artery (pA2 = 7.25). In the endothelium-denuded saphenous vein, 10 microM BQ123 shifted to the right only the response to high concentrations of endothelin-1. In vein but not in artery, endothelin-1 and sarafotoxin S6c induced an endothelium-dependent relaxation, which was increased, in the case of endothelin-1, in the presence of BQ123.2+.
authors.affiliation: Institut Henri Beaufour Research laboratories, Les Ulis, France.
authors.forename: M
authors.initials: M
authors.lastname: Auguet
authors.forename: S
authors.initials: S
authors.lastname: Delaflotte
authors.forename: P E
authors.initials: PE
authors.lastname: Chabrier
authors.forename: P
authors.initials: P
authors.lastname: Braquet
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001158:Arteries / Q000187:drug effects; D002217:Carbachol / Q000494:pharmacology; D065128:Endothelin Receptor Antagonists; D016232:Endothelins / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000187:drug effects; D066298:In Vitro Techniques; D008297:Male; D008969:Molecular Sequence Data; D009119:Muscle Contraction / Q000187:drug effects; D009126:Muscle Relaxation / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D010456:Peptides, Cyclic / Q000494:pharmacology; D011817:Rabbits; D017466:Receptors, Endothelin / Q000187:drug effects*; D012501:Saphenous Vein / Q000187:drug effects; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014757:Viper Venoms / Q000494:pharmacology
chemical_list: D065128:Endothelin Receptor Antagonists; D016232:Endothelins; D010456:Peptides, Cyclic; D017466:Receptors, Endothelin; D014662:Vasoconstrictor Agents; D014757:Viper Venoms; C057354:sarafotoxins s6; D002217:Carbachol; C072247:cyclo(Trp-Asp-Pro-Val-Leu)