中文摘要：

目的研究金丝桃苷（hyperoside,Hyp）对全脑缺血再灌注（cerebral ischemia-reperfusion,CIR）大鼠离体大脑中动脉（middle cerebral artery,MCA）的舒张作用及其机制。方法采用动脉加压灌注法、细胞膜电位记录法分别观察（1×10^-6～1×10^-4）mol·L^-1金丝桃苷对1×10^-7mol·L^-1U46619预收缩全脑缺血再灌注大鼠大脑中动脉的舒张作用和平滑肌细胞膜静息电位超极化反应;采用全自动酶标仪、硝酸还原酶法分别测定全脑缺血再灌注大鼠大脑组织硫化氢（H2S）和一氧化氮（NO）含量及金丝桃苷对其的影响。结果金丝桃苷能诱导U46619预收缩全脑缺血再灌注大鼠大脑中动脉产生明显的血管舒张反应和超极化现象（P〈0.01）,去除内皮细胞后,其效应显著减弱（P〈0.01）;单用一氧化氮合酶抑制剂左旋硝基精氨酸甲酯（3×10^-5mol·L^-1）或合用左旋硝基精氨酸甲酯（3×10^-5mol·L^-1）和前列环素合成酶抑制剂吲哚美辛（1×10^-5mol·L^-1）后,金丝桃苷介导大脑中动脉产生的舒张效应和超极化反应明显减弱,且全脑缺血再灌注组剩留的作用显著强于假手术（sham）组（P〈0.05,P〈0.01）;1×10^-3mol·L^-1KCa通道阻断剂四乙胺或1×10^-4mol·L^-1胱硫醚-γ-裂解酶抑制剂炔丙基甘氨酸（PPG）能明显减弱金丝桃苷诱导全脑缺血再灌注组大脑中动脉产生的非一氧化氮非前列环素样效应;与全脑缺血再灌注组比较,金丝桃苷组能显著降低一氧化氮含量,提高硫化氢含量。结论金丝桃苷能介导全脑缺血再灌注大鼠大脑中动脉产生内皮依赖性与内皮非依赖性血管舒张效应和超极化反应;在内皮依赖性舒张效应中,一氧化氮功能是下调的,而血管内皮依赖性超极化因子（endothelium-derived hyperpolarizing factor,EDHF）是上调的,即内源性硫化氢是上调的;金丝桃苷能升高全脑缺血再灌注大鼠脑组织中硫化氢含量,降低一氧化氮含量,产生?

英文摘要：

OBJECTIVE To investigate the dilatation and mechanism of hyperoside（Hyp） in middle cerebral arteries（MCA） of rats subjected to cerebral ischemia reperfusion（CIR）.METHODS Rat isolated MCA segments were used for surveying vasomotoricity in a pressurized chamber.Transmembrane potential was recorded by using glass microelectrodes to evaluate MCA vascular smooth muscle cell hyperpolarization.（1 ×10^-6-1 ×10^-4） mol·L^-1 Hyp was used to investigate the effects on vasodilatation and hyperpolarization in MCA of rats subjected to CIR.And the effects of nitric oxide synthase inhibitor（N-nitro-L-arginine-methyl-ester,L-NAME,3 ×10^-5mol·L^-1） or L-NAME plus prostaglandin I2 synthetase inhibitor（indomethacin,Indo,1 ×10^-5mol·L^-1） on vasorelaxation and hyperpolarization induced by Hyp were observed,respectively.Auto ELISA Detector and nitrate reductase methods were utilized to detect the H2S and NO content in the cerebrum of rats.RESULTS Hyp remarkably induced dose-dependent vasodilatation and hyperpolarization in 1 ×10^-7 mol·L^-1 U46619-preconstricted MCA of CIR rats.Hyp-mediated effects were notably attenuated after removal of endothelium in CIR MCA as compared with endothelium-intact group（P〈0.01）.After treatment with L-NAME or co-application of LNAME（3 ×10^-5mol·L^-1） plus Indo（1 ×10^-5mol·L^-1）,the vasodilatation and hyperpolarization evoked by Hyp were significantly attenuated in sham operation group and CIR MCAs.Compared with the residual effects in sham vessels,those of CIR MCAs were remarkably potentiated（P〈0.05,P〈0.01）.TEA（1 ×10^-3mol·L^-1）,an inhibitor of Ca2 ＋-activated potassium channel,or PPG（1 ×10^-4mol·L^-1）,an inhibitor of the endogenous H2S synthese-CSE could markedly restrain Hyp-induced non-NO and non-PGI2 relaxation and hyperpolarization in sham and CIR vessels.As compared with CIR group,pretreatment with Hyp increased the H2S contents while decreased the NO contents.CONCLUSION Hyp has the potential to evoke endothelium-dependent an