title: Attenuated endothelium-mediated relaxation by acteoside in rat aorta: Role of endothelial [Ca2+]i and nitric oxide/cyclic GMP pathway.
abstract: Acteoside and other phenylethanoid glycoside are contained in many plants that are widely used in traditional Chinese herbal medicine. Acteoside possesses multiple biological actions. Its effect on the vascular system is, however, incompletely understood. This study was aimed to investigate the role of endothelial [Ca2+]i, nitric oxide (NO), and cyclic GMP in acteoside-induced inhibition of endothelial NO-mediated relaxation in rat aorta. Acteoside reduced endothelial NO-dependent relaxation induced by acetylcholine (Ach) or A23187. Acteoside inhibited Ach-stimulated increase in tissue content of cyclic GMP in endothelium-intact rings. L-NNA abolished the stimulatory effect of Ach. Treatment with acteoside significantly suppressed bradykinin-induced increase in [Ca2+]i of cultured rat aortic endothelial cells. Acute exposure to acteoside (30 microM) did not affect the expression of eNOS mRNA in endothelium-intact rings. In summary, acteoside impairs endothelial NO-mediated aortic relaxation partially through inhibition of agonist-induced endothelial Ca2+ mobilization and Ca2+-dependent NO production and subsequent suppression of cyclic GMP formation. This novel pharmacological action if occurring in small vessels in vivo, may contribute to the reported anti-inflammatory effect of acteoside against NO-mediated vascular permeability-related acute edema.
authors.affiliation: Department of Physiology, Faculty of Medicine, Chinese University of Hong Kong, Shatin, NT, Hong Kong, China.
authors.forename: Chi-Wai
authors.initials: CW
authors.lastname: Lau
authors.forename: Zhen-Yu
authors.initials: ZY
authors.lastname: Chen
authors.forename: Chi-Ming
authors.initials: CM
authors.lastname: Wong
authors.forename: Xiaoqiang
authors.initials: X
authors.lastname: Yao
authors.forename: Zhendan
authors.initials: Z
authors.lastname: He
authors.forename: Hongxi
authors.initials: H
authors.lastname: Xu
authors.forename: Yu
authors.initials: Y
authors.lastname: Huang
mesh_terms: D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects / Q000378:metabolism; D002118:Calcium / Q000378:metabolism*; D006152:Cyclic GMP / Q000037:antagonists & inhibitors / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000378:metabolism; D005960:Glucosides / Q000494:pharmacology*; D066298:In Vitro Techniques; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000235:genetics / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III; D010636:Phenols / Q000494:pharmacology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014664:Vasodilation / Q000187:drug effects*; D014665:Vasodilator Agents / Q000494:pharmacology*; D059808:Polyphenols
chemical_list: D002118:Calcium; D006152:Cyclic GMP; D005960:Glucosides; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D052250:Nitric Oxide Synthase Type III; D010636:Phenols; D012333:RNA, Messenger; D014665:Vasodilator Agents; C058956:acteoside; D059808:Polyphenols; C496316:Nos3 protein, rat