title: Endothelium-dependent vasodilation induced by Hancornia speciosa in rat superior mesenteric artery.
abstract: The vasodilator effect of the ethanolic extract of leaves from Hancornia speciosa Gomes (HSE) was evaluated in superior mesenteric artery rings. HSE produced a concentration-dependent vasodilation (IC50 = 10.8 +/- 4.0 microg/mL) in arterial rings pre-contracted with phenylephrine, which was completely abolished in endothelium-denuded vessels. Endothelium-dependent vasodilation induced by HSE was strongly reduced by L-NAME (100 microM), a nitric oxide (NO) synthase inhibitor, but neither by atropine, a muscarinic receptor antagonist (1 microM), nor by indomethacin (10 microM), a cyclooxygenase inhibitor. In rings pre-contracted with 80 mM KCl, the vasodilator effect of HSE was shifted to the right and was completely abolished in the presence of L-NAME (100 microM). Similar effects were obtained in mesenteric rings pre-contracted with phenylephrine in the presence of KCl 25 mM alone or in addition to 100 microM L-NAME. In addition, BaCl2 (1 mM) dramatically reduced the vasodilation induced by HSE. Together, these findings led us to conclude that HSE induces an endothelium-dependent vasodilation in rat mesenteric artery, by a mechanism dependent on NO, on the activation of potassium channels and endothelium-derived hyperpolarizing factor release. Rutin, identified as a major peak in the HPLC fingerprint obtained for HSE, might contribute for the observed vasodilator effect, since it was able to induce an endothelium-dependent vasodilation in rat superior mesenteric arteries.
authors.affiliation: Departamento de Farmacologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Av. Antonio Carlos, CEP 31270-901 Belo Horizonte, Brazil.
authors.forename: H C
authors.initials: HC
authors.lastname: Ferreira
authors.forename: C P
authors.initials: CP
authors.lastname: Serra
authors.forename: D C
authors.initials: DC
authors.lastname: Endringer
authors.forename: V S
authors.initials: VS
authors.lastname: Lemos
authors.forename: F C
authors.initials: FC
authors.lastname: Braga
authors.forename: S F
authors.initials: SF
authors.lastname: Cortes
mesh_terms: D000818:Animals; D029062:Apocynaceae / Q000737:chemistry*; D004305:Dose-Response Relationship, Drug; D004727:Endothelium / Q000187:drug effects*; D008297:Male; D008638:Mesenteric Arteries / Q000187:drug effects*; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry; D051381:Rats; D017208:Rats, Wistar; D014664:Vasodilation / Q000187:drug effects*
chemical_list: D010936:Plant Extracts