title: [Vasodilator effect of oroxylin A on thoracic aorta isolated from rats].
abstract: OBJECTIVE
  To investigate the vasodilator effect and the endothelium-dependent mechanism of oroxylin A in thoracic aorta isolated from rats.
  
  
  METHODS
  Thoracic aorta was isolated from Wistar rats. After pretreatment with norepinephrine or KCl, the effects of oroxylin A at different concentrations were detected on isolated vascular rings prepared from rats' thoracic aorta. The response of thoracic aortic ring was evaluated in the presence and absence of endothelium, and NG-nitro-L-arginine methyl ester (L-NAME), a specific inhibitor of nitric oxide synthase.
  
  
  RESULTS
  Oroxylin A (10 and 100 μmol/L) caused vasodilation on endothelium-intact aortic rings pretreated with norepinephrine (1 μmol/L) and KCl (60 mmol/L) compared with the control (P<0.05, P<0.01). The vasodilation function of 10 and 100 μmol/L oroxylin A on the endothelium-denuded aorta rings was significantly lower than that on the endothelium-intact aorta rings (P<0.05, P<0.01). L-NAME pretreatment significantly attenuated the effect of 100 μmol/L oroxylin A on endothelium-intact aorta rings (P<0.05, P<0.01).
  
  
  CONCLUSIONS
  Oroxylin A can induce the relaxation of the aorta ring in endothelium-dependent manner. Nitric oxide may be involved in the endothelium-dependent effect of oroxylin A.
authors.affiliation: Tianjin State Key Laboratory of Modern Chinese Medicine, Research Institute of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, China. wanghongsys@126.com
authors.forename: Hong
authors.initials: H
authors.lastname: Wang
authors.forename: Jing-Tian
authors.initials: JT
authors.lastname: Qu
authors.forename: Xin
authors.initials: X
authors.lastname: Zhao
authors.forename: Ying
authors.initials: Y
authors.lastname: Guo
authors.forename: Hao-Ping
authors.initials: HP
authors.lastname: Mao
mesh_terms: D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects* / Q000502:physiology; D004730:Endothelium, Vascular / Q000187:drug effects / Q000502:physiology; D005419:Flavonoids / Q000494:pharmacology*; D066298:In Vitro Techniques; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D014664:Vasodilation; D014665:Vasodilator Agents / Q000494:pharmacology*
chemical_list: D005419:Flavonoids; D014665:Vasodilator Agents; C080669:5,7-dihydroxy-6-methoxy-2-phenylchromen-4-one