title: Age-related changes in isoprostane-mediated relaxation of piglet blood vessels.
abstract: We studied the putative relaxant effects of several isoprostanes (8-iso-PGE1, and 8-iso-PGE2, 8-iso-PGF1alpha, 8-iso-PGF1beta, 8-iso-PGF2alpha, and 8-iso-PGF2beta) on pulmonary (PA), mesenteric (MA), coronary (CA) arteries and pulmonary veins (PV), from newborn and 2-week-old piglets. Isoprostanes were compared with agonists of the EP (PGE1, PGE2, and misoprostol), DP (PGD2), and IP (iloprost) receptors. Isoprostane-induced relaxation was only observed when TP receptors were occupied (by U46619) or blocked (by SQ 29,548). Under these conditions, 8-iso-PGE2 induced a relaxation of PA (but not PV or MA) that increased with postnatal age. 8-iso-PGE1, 8-iso-PGE2, and 8-iso-PGF2alpha evoked modest relaxations in CA. 8-iso-PGE2-induced relaxation of PA was impaired by endothelium removal and by the presence of blockers of NO synthase (L-NAME), guanylate cyclase (ODQ), or EP receptor (AH6809). PGE1, PGE2, and misoprostol (but not PGD2 or iloprost) induced a relaxation of PA that increased with age. In conclusion, occupancy or blockade of TP receptors unmasked a relaxant effect of 8-iso-PGE2 in piglet PA. This relaxation increased with postnatal age, was endothelium-dependent and involved EP receptors and NO.
authors.affiliation: Division of Neonatology, Department of Pediatrics, Hospital Universitario Materno-Infantil de Canarias, 35016 Las Palmas de Gran Canaria, Spain.
authors.forename: Gema
authors.initials: G
authors.lastname: Gonzalez-Luis
authors.forename: Francisco
authors.initials: F
authors.lastname: Perez-Vizcaino
authors.forename: Carlos E
authors.initials: CE
authors.lastname: Blanco
authors.forename: Eduardo
authors.initials: E
authors.lastname: Villamor
mesh_terms: D000367:Age Factors; D000704:Analysis of Variance; D000818:Animals; D003331:Coronary Vessels / Q000187:drug effects; D006162:Guanylate Cyclase / Q000378:metabolism; D028421:Isoprostanes / Q000494:pharmacology*; D008638:Mesenteric Arteries / Q000187:drug effects; D019331:NG-Nitroarginine Methyl Ester / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D011651:Pulmonary Artery / Q000187:drug effects; D011667:Pulmonary Veins / Q000187:drug effects; D034421:Sus scrofa; D014664:Vasodilation / Q000187:drug effects*; D044004:Xanthones / Q000378:metabolism
chemical_list: D028421:Isoprostanes; D044004:Xanthones; C053876:6-isopropoxy-9-oxoxanthene-2-carboxylic acid; D019001:Nitric Oxide Synthase; D006162:Guanylate Cyclase; D019331:NG-Nitroarginine Methyl Ester