槲皮素对大鼠主动脉环的舒张作用及机制

VASODILATOR EFFECTS OF QUERCETIN ON THORACIC AORTA IN RAT

目的:探讨槲皮素(Que)对大鼠离体胸主动脉环的舒张作用及其舒张机制。方法:采用离体血管环技术制备大鼠胸主动脉环,使用累积加药法,检测Que对去甲肾上腺素预收缩的胸主动脉环张力的影响。结果:Que对离体大鼠内皮完整和去内皮的胸主动脉环均呈剂量依赖性扩血管作用。在小剂量Que(1×10-6,3×10-6,1×10-5mol/L)浓度,内皮完整和去内皮胸主动脉环的扩血管作用之间差异无显著统计学意义,但在较大剂量Que(3×10-5,6×10-5mol/L),去内皮后其舒血管作用显著性减弱(P﹤0.05)。用环氧合酶抑制剂吲哚美辛,钙激活钾通道抑制剂CHTX分别预处理后,Que在各剂量组引起的舒张血管作用与不加阻滞剂比较无统计学意义(P>0.05)。用一氧化氮合酶抑制剂L-NAME预处理后,Que在较大剂量(3×10-5,6×10-5mol/L)引起的舒张血管作用明显减低,与不加阻滞剂比较,有统计学差异(P<0.05)。结论:槲皮素具有剂量依赖性的舒张血管作用。其舒张作用与前列腺素、钙激活钾通道无关,而与内皮一氧化氮有关。

Objective ：To determine the relaxing effects and mechanism of quercetin on isolated thoracic aorta of rat. Methods：Method of vitro vascular perfusion was adopted to pre-contract the vessels with 10^-6 mol/L of noradrenaline （NE）.The effects of quercetin on the aorta rings with intact or removal of endothelium were determined, and N^ω-nitro-L-arginine methylester （L-NAME ,nitric oxide synthase inhibitor）, CHTX （potent and selective blockor of the calcium-activated potassium channel）, indomethacin （cyclooxygenase inhibitor） were used to explore the mechanism. Results：Quercetin could produce relaxation of aorta rings precontracted by NE with endothelium intact or denuded in a dose dependent manner. Vasodilatation effect of quercetin was weak in low dose（1×10^-6,3×10^-6, 1×10^-5 mol/L）. Vasodilatation effect was strong when the dose of quercetin was higher than 3× 10^5mol/L （P〈0.05）. After endothelium denuded, vasorelaxation were decreased in every dose group but quercetin （3×10^-5,6×10^-5mol/L） was more potent, there was significant difference（P〈0.05）. Pretreatment with CHTX （10^-7 mol/ L ） or indomethacin （10^-5 mol/L） couldn＇t cancel the vasorelaxation by quercetin （P〉0.05）. Pretreatment with L- NAME（10^-5 mol/L） tenuated the vasorelaxation effect of quercatin （3×10^-5,6×10^-5 mol/L） ,and there was difference compared with control group （P〈0.05）. Conclusion：Quercetin shows vasodilator effects on a dose-dependent manner. The vasodilatation effect of quercetin is mediated by endothelium nitric oxide pathway, but is unrelated to cyclooxygenase pathway and calcium-activated potassium channel pathway.