title: Nociceptin, an endogenous ligand for the ORL1 receptor, has vasodilator activity in the hindquarters vascular bed of the rat.
abstract: The heptadecapeptide nociceptin, also known as Orphanin FQ, is a newly discovered endogenous ligand for the G-protein coupled, opioid-like receptor ORL1. In the present study, responses to intra-arterial injections of nociceptin were investigated in the hindquarters vascular bed of the rat. Under constant-flow conditions nociceptin induced dose-dependent decreases in hindquarters perfusion pressure when injected in doses of 1-30 nmol into the hindquarters perfusion circuit. The decreases in hindquarters perfusion pressure were rapid in onset and pressure returned to control values over a 3-6 min period. In terms of relative vasodilator activity, nociceptin was approximately equipotent to the nitric oxide donor, DEA/NO, and 30-fold less potent than adrenomedullin. These data demonstrate that nociceptin has significant vasodilator activity in the hindquarters vascular bed of the rat.
authors.affiliation: Department of Pharmacology, Tulane University School of Medicine, New Orleans, LA 70112, USA.
authors.forename: M A
authors.initials: MA
authors.lastname: Czapla
authors.forename: H C
authors.initials: HC
authors.lastname: Champion
authors.forename: P J
authors.initials: PJ
authors.lastname: Kadowitz
mesh_terms: D053607:Adrenomedullin; D000818:Animals; D005260:Female; D006614:Hindlimb / Q000098:blood supply; D006834:Hydrazines / Q000494:pharmacology; D007269:Injections, Intra-Arterial; D008024:Ligands; D008297:Male; D009589:Nitrogen Oxides; D018847:Opioid Peptides / Q000008:administration & dosage / Q000378:metabolism / Q000494:pharmacology*; D010455:Peptides / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011957:Receptors, Opioid / Q000819:agonists* / Q000378:metabolism*; D014660:Vasoactive Intestinal Peptide / Q000494:pharmacology; D014665:Vasodilator Agents / Q000494:pharmacology*; D000094942:Nociceptin Receptor; D000097629:Nociceptin
chemical_list: D053607:Adrenomedullin; D006834:Hydrazines; D008024:Ligands; D009589:Nitrogen Oxides; D018847:Opioid Peptides; D010455:Peptides; D011957:Receptors, Opioid; D014660:Vasoactive Intestinal Peptide; D014665:Vasodilator Agents; D000094942:Nociceptin Receptor; D000097629:Nociceptin; C084012:1,1-diethyl-2-hydroxy-2-nitrosohydrazine; C000722285:Oprl1 protein, rat