title: Vasorelaxant responses to endomorphins, nociceptin, albuterol, and adrenomedullin in isolated rat aorta.
abstract: The endogenous peptides endomorphins 1 and 2 are newly discovered, potent, selective mu-opioid receptor agonists. In the present study, the effects of endomorphins 1 and 2 on vascular smooth muscle tone were investigated on isolated rings from rat aorta with and without endothelium. In rings precontracted with phenylephrine, endomorphins 1 and 2 at concentrations of 0.1 and 1.0 microM, nociceptin at concentrations of 1-100 microM, and adrenomedullin at concentrations of 0.01-1.0 microM induced concentration dependent relaxant responses. The endomorphins and nociceptin were less potent than adrenomedullin. No relaxation was induced by endomorphins 1 and 2 in aortic rings denuded of endothelium and precontracted with phenylephrine. The results of the present studies demonstrate that the endomorphins relax aortic vascular smooth muscle from the rat aorta by an endothelium-dependant mechanism.
authors.affiliation: Department of Anatomy, Tulane University School of Medicine, New Orleans, LA 70112-2699, USA.
authors.forename: S Y
authors.initials: SY
authors.lastname: Hugghins
authors.forename: H C
authors.initials: HC
authors.lastname: Champion
authors.forename: G
authors.initials: G
authors.lastname: Cheng
authors.forename: P J
authors.initials: PJ
authors.lastname: Kadowitz
authors.forename: J R
authors.initials: JR
authors.lastname: Jeter
mesh_terms: D053607:Adrenomedullin; D000420:Albuterol / Q000494:pharmacology; D000701:Analgesics, Opioid / Q000494:pharmacology*; D000818:Animals; D001012:Aorta, Abdominal / Q000187:drug effects; D001013:Aorta, Thoracic / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000502:physiology; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000502:physiology*; D009842:Oligopeptides / Q000494:pharmacology*; D018847:Opioid Peptides / Q000494:pharmacology; D010455:Peptides / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D017450:Receptors, Opioid, mu / Q000819:agonists; D014665:Vasodilator Agents / Q000494:pharmacology*; D000097629:Nociceptin
chemical_list: D053607:Adrenomedullin; D000420:Albuterol; D000701:Analgesics, Opioid; D009842:Oligopeptides; D018847:Opioid Peptides; D010455:Peptides; D017450:Receptors, Opioid, mu; D014665:Vasodilator Agents; D000097629:Nociceptin; C105293:endomorphin 1; C105294:endomorphin 2