Vasorelaxant responses to endomorphins, nociceptin, albuterol, and adrenomedullin in isolated rat aorta

• Published in: Life sciences (1973) Vol. 67; no. 4; pp. 471 - 476
• Main Authors: Hugghins, Stephanie Y., Champion, Hunter C., Cheng, Georgina, Kadowitz, Philip J., Jeter, James R.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Inc 16.06.2000
• Subjects: Adrenomedullin; Albuterol; Albuterol - pharmacology; Analgesics, Opioid - pharmacology; Animals; Aorta, Abdominal - drug effects; Aorta, Thoracic - drug effects; Aortic strips; Dose-Response Relationship, Drug; Endomorphin 1; Endomorphin 2; Endothelium, Vascular - physiology; Endothelium-dependent vasodilator; In Vitro Techniques; Male; Muscle Contraction - drug effects; Muscle Contraction - physiology; Muscle, Smooth, Vascular - drug effects; Muscle, Smooth, Vascular - physiology; Nociceptin; Oligopeptides - pharmacology; Opioid Peptides - pharmacology; Peptides - pharmacology; Rat aorta; Rats; Rats, Sprague-Dawley; Receptors, Opioid, mu - agonists; Vasodilator; Vasodilator Agents - pharmacology; Vasodilator peptides; Vasorelaxant response; μ-Opioid receptor agonist; Nociceptin; Rat aorta; Endomorphin 2; Endomorphin 1; Vasorelaxant response; Vasodilator; Adrenomedullin; Endothelium-dependent vasodilator; μ-Opioid receptor agonist; Albuterol; Aortic strips; Vasodilator peptides
• ISSN: 0024-3205; 1879-0631
• DOI: 10.1016/S0024-3205(00)00631-7

The endogenous peptides endomorphins 1 and 2 are newly discovered, potent, selective μ-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 μM, nociceptin at concentrations of 1–100 μM, and adrenomedullin at concentrations of 0.01–1.0 μM 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.