title: Ex vivo study of the vasorelaxant activity induced by phenanthrene derivatives isolated from Maxillaria densa.
abstract: The phenanthrenes gymnopusin (1), fimbriol A (2), and erianthridin (3) from Maxillaria densa were found to induce significant relaxant effects in a concentration-dependent and endothelium-independent manner on aortic rings precontracted with norepinephrine (NE, 0.1 μM) and KCl (80 mM). Compound 1 was the most active and also inhibited the cumulative concentration-response contraction of NE or CaCl(2). Contractions induced by FPL 64176, an agonist of L-type voltage-dependent calcium channels, were blocked by 1. The potassium channel blockers glibenclamide and TEA (tetraethylammonium) reduced the relaxations induced by 1. Nevertheless, the effect of 1 was not modified by 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one, a specific soluble guanylate cyclase inhibitor. The functional results obtained suggest that 1 induces relaxation through an endothelium-independent pathway by the control of cationic channels (calcium channel blockade and potassium channel opening) in the myogenic response of rat aortic rings.
authors.affiliation: Universidad Autónoma del Estado de Morelos, Avenida Universidad 1001, Colonia Chamilpa, 62209. Cuernavaca, Morelos, México.
authors.forename: Priscila
authors.initials: P
authors.lastname: Rendón-Vallejo
authors.forename: Oswaldo
authors.initials: O
authors.lastname: Hernández-Abreu
authors.forename: Jorge
authors.initials: J
authors.lastname: Vergara-Galicia
authors.forename: César
authors.initials: C
authors.lastname: Millán-Pacheco
authors.forename: Armando
authors.initials: A
authors.lastname: Mejía
authors.forename: Maximiliano
authors.initials: M
authors.lastname: Ibarra-Barajas
authors.forename: Samuel
authors.initials: S
authors.lastname: Estrada-Soto
mesh_terms: D000818:Animals; D008297:Male; D009638:Norepinephrine / Q000494:pharmacology; D010616:Phenanthrenes / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D026902:Potassium Channel Blockers / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D051381:Rats; D014664:Vasodilation / Q000187:drug effects; D014665:Vasodilator Agents / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*
chemical_list: D010616:Phenanthrenes; D026902:Potassium Channel Blockers; D014665:Vasodilator Agents; C468819:erianthridin; C578487:fimbriol A; C468821:gymnopusin; D009638:Norepinephrine