title: The mechanism of vasorelaxation induced by ethanol extract of Sophora flavescens in rat aorta.
abstract: OBJECTIVE
  Sophora flavescens (SF) is a known medicinal herb for the treatment of cardiovascular symptoms associated with arrhythmia in China. However, the pharmacological action mechanisms involved have not been well studied. The aim of the present study was to define effects of roots of SF on the vascular tension and responsible mechanisms in rat thoracic aorta.
  
  
  METHODS
  Ethanol extract of the roots of SF (ESF) was examined for their vascular relaxant effect in isolated phenylephrine-precontracted rat thoracic aorta.
  
  
  RESULTS
  ESF (0.1-100 μg/ml) induced relaxation of the phenylephrine-precontracted aortic rings in a concentration-dependent manner. Endothelium-denudation abolished the ESF-induced vasorelaxation. Pretreatment of the endothelium-intact aortic rings with l-NAME, an inhibitor of nitric oxide synthase, and ODQ, an inhibitor of soluble guanylyl cyclase (sGC), inhibited ESF-induced vasorelaxation. ESF increased cGMP levels of the aortic rings in a concentration-dependent manner and the effect was blocked by l-NAME and ODQ. Inhibition of K(+) channels with glibenclamide and tetraethylammonium, cyclooxygenase inhibition with indomethacin, and β-adrenergic and muscarinic receptors blockade had no effect on the ESF-induced vasorelaxation.
  
  
  CONCLUSIONS
  These findings suggest that ESF relaxes vascular smooth muscle via endothelium-dependent NO-sGC-cGMP signaling pathway.
authors.affiliation: Institute of Materia Medica, Taishan Medical University, Middle of Changcheng Road, Taian, Shandong 271016, China. snjin0504@yahoo.com.cn
authors.forename: Song Nan
authors.initials: SN
authors.lastname: Jin
authors.forename: Jin Fu
authors.initials: JF
authors.lastname: Wen
authors.forename: Xiang
authors.initials: X
authors.lastname: Li
authors.forename: Dae Gill
authors.initials: DG
authors.lastname: Kang
authors.forename: Ho Sub
authors.initials: HS
authors.lastname: Lee
authors.forename: Kyung Woo
authors.initials: KW
authors.lastname: Cho
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects* / Q000378:metabolism; D006152:Cyclic GMP / Q000378:metabolism; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004365:Drugs, Chinese Herbal / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D000431:Ethanol / Q000737:chemistry*; D006162:Guanylate Cyclase / Q000037:antagonists & inhibitors / Q000378:metabolism; D008297:Male; D018727:Muscarinic Antagonists / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000378:metabolism; D018517:Plant Roots; D010946:Plants, Medicinal; D026902:Potassium Channel Blockers / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D018160:Receptors, Cytoplasmic and Nuclear / Q000037:antagonists & inhibitors / Q000378:metabolism; D000071756:Soluble Guanylyl Cyclase; D012997:Solvents / Q000737:chemistry*; D029909:Sophora / Q000737:chemistry; D014664:Vasodilation / Q000187:drug effects*; D014665:Vasodilator Agents / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*
chemical_list: D000319:Adrenergic beta-Antagonists; D016861:Cyclooxygenase Inhibitors; D004365:Drugs, Chinese Herbal; D004791:Enzyme Inhibitors; D018727:Muscarinic Antagonists; D026902:Potassium Channel Blockers; D018160:Receptors, Cytoplasmic and Nuclear; D012997:Solvents; D014665:Vasodilator Agents; D009569:Nitric Oxide; D000431:Ethanol; D019001:Nitric Oxide Synthase; D006162:Guanylate Cyclase; D000071756:Soluble Guanylyl Cyclase; D006152:Cyclic GMP