title: Pharmacological study of the mechanisms involved in the vasodilator effect produced by the acute application of triiodothyronine to rat aortic rings.
abstract: A relationship between thyroid hormones and the cardiovascular system has been well established in the literature. The present in vitro study aimed to investigate the mechanisms involved in the vasodilator effect produced by the acute application of 10-8-10-4 M triiodothyronine (T3) to isolated rat aortic rings. Thoracic aortic rings from 80 adult male Wistar rats were isolated and mounted in tissue chambers filled with Krebs-Henseleit bicarbonate buffer in order to analyze the influence of endothelial tissue, inhibitors and blockers on the vascular effect produced by T3. T3 induced a vasorelaxant response in phenylephrine-precontracted rat aortic rings at higher concentrations (10-4.5-10-4.0 M). This outcome was unaffected by 3.1×10-7 M glibenclamide, 10-3 M 4-aminopyridine (4-AP), 10-5 M indomethacin, or 10-5 M cycloheximide. Contrarily, vasorelaxant responses to T3 were significantly (P<0.05) attenuated by endothelium removal or the application of 10-6 M atropine, 10-5 M L-NG-nitroarginine methyl ester (L-NAME), 10-7 M 1H-(1,2,4)oxadiazolo[4,3-a]quinoxalin-1-one (ODQ), 10-6 M (9S,10R,12R)-2,3,9,10,11,12-Hexahydro-10-methoxy-2,9-dimethyl-1-oxo-9,12-epoxy-1H-diindolo[1,2,3-fg:3',2',1'-kl]pyrrolo[3,4-i](1,6)benzodiazocine-10-carboxylic acid, methyl ester KT 5823, 10-2 M tetraethylammonium (TEA), or 10-7 M apamin plus 10-7 M charybdotoxin. The results suggest the involvement of endothelial mechanisms in the vasodilator effect produced by the acute in vitro application of T3 to rat aortic rings. Possible mechanisms include the stimulation of muscarinic receptors, activation of the NO-cGMP-PKG pathway, and opening of Ca2+-activated K+ channels.
authors.affiliation: Department of Cellular Biology, National Institute of Perinatology, Mexico City, Mexico.
authors.forename: J
authors.initials: J
authors.lastname: Lozano-Cuenca
authors.affiliation: Section of Postgraduate Studies and Investigation, Higher School of Medicine, National Polytechnic Institute, Mexico City, Mexico.
authors.forename: O A
authors.initials: OA
authors.lastname: López-Canales
authors.affiliation: Department of Cellular Biology, National Institute of Perinatology, Mexico City, Mexico.
authors.forename: J C
authors.initials: JC
authors.lastname: Aguilar-Carrasco
authors.affiliation: Department of Infectology and Perinatal Immunology, National Institute of Perinatology, Mexico City, Mexico.
authors.forename: J R
authors.initials: JR
authors.lastname: Villagrana-Zesati
authors.affiliation: Section of Postgraduate Studies and Investigation, Higher School of Medicine, National Polytechnic Institute, Mexico City, Mexico.
authors.forename: R M
authors.initials: RM
authors.lastname: López-Mayorga
authors.affiliation: Section of Postgraduate Studies and Investigation, Higher School of Medicine, National Polytechnic Institute, Mexico City, Mexico.
authors.forename: E F
authors.initials: EF
authors.lastname: Castillo-Henkel
authors.affiliation: Department of Cellular Biology, National Institute of Perinatology, Mexico City, Mexico.
authors.forename: J S
authors.initials: JS
authors.lastname: López-Canales
mesh_terms: D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects*; D001285:Atropine / Q000494:pharmacology; D004121:Dimethyl Sulfoxide / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000187:drug effects*; D005905:Glyburide / Q000494:pharmacology; D007213:Indomethacin / Q000494:pharmacology; D008297:Male; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D010656:Phenylephrine / Q000494:pharmacology; D024681:Potassium Channels, Calcium-Activated / Q000187:drug effects; D017208:Rats, Wistar; D014284:Triiodothyronine / Q000494:pharmacology*; D014664:Vasodilation / Q000187:drug effects*; D014665:Vasodilator Agents / Q000494:pharmacology*
chemical_list: D024681:Potassium Channels, Calcium-Activated; D014665:Vasodilator Agents; D014284:Triiodothyronine; D010656:Phenylephrine; D001285:Atropine; D005905:Glyburide; D019331:NG-Nitroarginine Methyl Ester; D007213:Indomethacin; D004121:Dimethyl Sulfoxide