异鼠李素对大鼠主动脉环的舒张作用

目的：研究异鼠李素（Iso）对离体大鼠胸主动脉环的舒张作用,并探讨其可能的舒张机制。方法：采用累计加药法,观察Iso、槲皮素（Que）和硝普钠对大鼠主动脉血管环的舒张作用,以及内皮一氧化氮合酶（eNOS）选择性抑制剂左旋硝基精氨酸甲酯（L-NAME）、鸟苷酸环化酶（GC）抑制剂亚甲蓝（MB）、前列腺素（PGs）抑制剂吲哚美辛（Indo）、ATP依赖钾通道（KATP）选择性抑制剂格列本脲（GLY）对Iso舒张去甲肾上腺素（NE）收缩的胸主动脉环的影响。结果：Iso（1100μmol/L）与Que（1100μmol/L）对离体大鼠内皮完整胸主动脉环均有浓度依赖性的舒张作用,且Iso与Que的舒张效应没有明显差异（P〉0.05）,两者均在10-4mol∕L时舒张作用达到100%。Iso与Que最大舒张反应的半数有效浓度（EC50）分别为4.26×10-5mol/L,4.28×10-5mol/L,两者的EC50无明显差别（P〉0.05）。Iso和硝普钠相比,对内皮完整胸主动脉环的舒张能力显著减少（P〈0.01）。Iso在低浓度（1～30μmol/L）的舒张作用内皮完整组明显强于去内皮组（P〈0.05）,而在高浓度（60100μmol/L）时,去内皮组与保留内皮组的舒血管作用无显著性差异（P〉0.05）。L-NAME、MB及Indo均可以部分阻断Iso的舒血管作用,与对照组比有统计学意义差异（P〈0.05）,而GLY不能阻断Iso的舒血管作用,与对照组比差异无统计学意义（P〉0.05）。结论：异鼠李素对离体大鼠动脉环可产生浓度依赖的舒张作用,异鼠李素在低浓度时舒血管作用具有内皮依赖性,而在高浓度时,为非内皮依赖性机制。异鼠李素舒血管机制可能与内皮NO/GC/cGMP途径以及环氧合酶途径有关,与ATP激活钾通道无关。

VASODILATATION EFFECT OF ISORHAMNETIN ON THE ISOLATED THORACIC AORTA IN RAT

objactive：To determine the possible vasodialation effect of isorhamnetinin（Iso） on the isolated thoracic aorta in rat.Methods： The isolated thoracic aortic rings in rat were suspended in organ baths containing Krebs solution,and then isometric tension was measured.Preconstricted with noradrenaline（NE）,the vasodilathion effect of Iso,quercetin（Que） and nitroprusside natrum on aortic rings with endothelium or without endothelium were measured by tension change records in vitro.The effect of vasodilathion was also observed in the presence and absence of L-N（G）-nitroarginine methy-ester（L-NAME100μmol/l）,Indo（10μmol/L）,methylene blue（MB10μmol/L） and Glibenclamide（GLY10μmol/L）.Results： Iso（1100μmol/L） and Que（1100μmol/L） caused vasodilathion of the isolated thoracic aortic rings with endothelium on a does dependent manner.Vasodilathion ef-fect of the isolated thoracic aortic rings between Iso group and Que group had no obviously difference（P〉0.05）,and both had maximal vasodilathion effect on 100μmol/ L.EC50 of Iso group and Que group were 4.26×10-5mol/L and 4.28× 10-5mol/L respectively（P〉0.05）.But compared with nitroprusside natrum,vasodialation effect of Iso ex-cellently decreased（P〈0.01）.Compared with no-endothelium group,Iso（1～30μmol/L） had better vasodilathion effect of thoracic aorta rings with endothelium group（P〈0.05）;compared with control group,L-NAME,Indo and MB could respectively inhibit vasodilathion effect of Iso on thoracic aortic rings with endothelium（P〈0.05）.Com-pared with control group,GLY group had no obviously different effect on aorta rings with endothelium（P〉0.05）.Conclusions： These findings suggest that Iso have a does-dependent vasodilathion effect on thoracic aortic rings with endothelium or without endothelium.In low-does,Iso causes vasodilathion effect on endothelium-dependent pathway,and the mechanism might be mediated by NO、guanylyl cyclade and cyclooxygenase-dependent pathway;but Iso in high-does causes vasodilathion on endothelium-independent pathway.