千层纸素A内皮依赖性舒张大鼠离体血管的作用

目的：研究千层纸素A对离体大鼠胸主动脉的血管舒张作用及其内皮依赖性作用机制。方法：分离wistar大鼠的胸主动脉,采用离体大鼠胸主动脉环张力测定法检测千层纸素A对1Mmol／L去甲肾上腺素（norepinephrine,NE）或60mmol／L氯化钾预收缩的大鼠离体胸主动脉环的舒张效应,并观察去内皮或用一氧化氮合酶抑制剂N-硝基L-精氨酸甲酯（NG-nitro-Largininemethylester,LNAME）预处理后千层纸素A舒张血管作用的变化。结果：千层纸素A（10、100μmol／L）可以舒张NE（1μmol／L）和氯化钾（60mmol／L）预收缩的内皮完整的离体血管,10、100μmol／L药物浓度组与溶剂对照组比较差异有统计学意义（P〈0．05,P〈0．01）;对去内皮血管的舒张作用显著低于内皮完整的血管（P〈0．05,P〈0．01）;终浓度为100μmol／L的L—NAME可以显著降低100μmol／L千层纸素A的舒血管作用,加入L—NAME组-9不加入抑制剂组比较差异有统计学意义（P〈0．05,P〈0．01）。结论：千层纸素A可通过内皮依赖的一氧化氮途径发挥舒张血管的作用。

Vasodilator effect of oroxylin A on thoracic aorta isolated from rats

OBJECTIVE： To investigate the vasodilator effect and the endothelium-dependent mechanism of oroxylin A in thoracic aorta isolated from rats. METHODS= Thoracic aorta was isolated from Wistar rats. After pretreatment with norepinephrine or KCI, the effects of oroxylin A at different concentrations were detected on isolated vascular rings prepared from rats＇ thoracic aorta. The response of thoracic aortic ring was evaluated in the presence and absence of endothelium, and NG-nitro-L-arginine methyl ester （L-NAME）, a specific inhibitor of nitric oxide synthase. RESULTS： Oroxylin A （10 and 100 μmol/L） caused vasodilation on endothelium-intact aortic rings pretreated with norepinephrine （1 μmol/L） and KCI （60 mmol/L） compared with the control （P〈0.05, P〈0.01）. The vasodilation function of 10 and 100μmol/L oroxylin A on the endothelium-denuded aorta rings was significantly lower than that on the endothelium-intact aorta rings （P〈0.05, P〈0.01）. L-NAME pretreatment significantly attenuated the effect of 100 μmol/L oroxylin A on endothelium-intact aorta rings （P〈0.05, P〈0.01）. CONCLUSION Oroxylin A can induce the relaxation of the aorta ring in endothelium-dependent manner. Nitric oxide may be involved in the endothelium-dependent effect of oroxylin A.