(-)Epicatechin induces and modulates endothelium-dependent relaxation in isolated rat mesenteric artery rings  

作　　者：ChenZY YaoXQ 

机构地区：[1]DepartmentofBiochemistry,ChineseUniversityofHongKong,China [2]DepartmentofPhysiology,ChineseUniversityofHongKong,China

出　　处：《Acta Pharmacologica Sinica》2002年第12期1188-1192,共5页中国药理学报（英文版）

摘　　要：AIM: The present study was aimed to examine the role of endothelial nitric oxide in the relaxant response to green tea (-)epicatechin and its modulation of endothelium-mediated relaxation in the isolated rat mesenteric artery rings. METHODS: Changes in the isometric tension were measured with Grass force-displacement transducers. RESULTS: The (-)epicatechin-induced relaxation was largely dependent on the presence of intact endothelium and was reversed by NG-nitro-L-arginine methyl ester 10 micromol/L or methylene blue 10 micromol/L, the inhibitors of nitric oxide-mediated relaxation. L-Arginine at 1 mmol/L antagonized the effect of L-NAME or methylene blue. Pretreatment of endothelium-intact rings with (-)epicatechin 10 micromol/L enhanced the relaxation induced by endothelium-dependent vasodilator, acetylcholine, while this concentration did not influence the endothelium-independent relaxation induced by sodium nitroprusside in the endothelium-denuded artery rings. CONCLUSION: The results indicate that the endothelium-dependent vasodilation by (-)epicatechin is mainly mediated through nitric oxide and low concentration of (-)epicatechin augments endothelium-dependent vasorelaxation in the rat mesenteric arteries.AIM:The present study was aimed to examine the role of endothelial nitric oxide in the relaxant response to green tea (-)epicatechin and its modulation of endothelium-mediated relaxation in the isolated rat mesenteric artery rings.METHODS:Changes in the isometric tension were measured with Grass force-displacement transducers.RESULTS:The (-)epicatechin-induced relaxation was largely dependent on the presence of intact endothelium and was reversed by N^G-nitro-L-arginine methyl ester 10μmol/L or methylene blue 10μmol/L，the inhibitors of nitric oxidemediated relaxation.L-Arginine at 1mmol/L antagonized the effect of L-NAME or methylene blue.Pretreatment of endothelium-intact rings with (-)epicatechin 10μmol/L enhanced the relaxation induced by endothelium-dependent vasodilator,acetylcholine,while this concentration did not influence the endothelium-independent relaxation induced by sodium nitroprusside in the endothelium-denuded artery rings.CONCLUSION:The results indicate that the endothelium-dependent vasodilation by (-)epicatechin is mainly mediated through nitric oxide and low concentration of (-)epicatechin augments endothelium-dependent vasorelaxation in the rat mesenteric arteries.

关 键 词：Animals CATECHIN Endothelium  Vascular In Vitro Male Mesenteric Arteries Methylene Blue Muscle  Smooth  Vascular NG-Nitroarginine Methyl Ester Nitric Oxide Synthase PHENYLEPHRINE RATS Rats  Sprague-Dawley Research Support  Non-U.S. Gov't STEREOISOMERISM Tea VASODILATION 

分 类 号：R285.5[医药卫生—中药学]