银杏达莫注射液对高钾血症大鼠离体血管张力的影响

Effects of Ginkgo leaf extract and dipyridamole injection on tension of thoracic aorta rings of rats with hyperkalemia

目的:观察银杏达莫注射液(GD)对高钾血症大鼠离体胸主动脉的影响,并探讨其可能作用机制。方法:复制高钾血症大鼠模型,制备离体胸主动脉环,经生物信号与采集分析系统测定主动脉环的张力变化。观察不同浓度GD(4、8、16 mg/L)预孵育的高钾血症大鼠胸主动脉血管环对去氧肾上腺素(PE)和KC l收缩张力的影响。结果:与正常大鼠相比,高钾血症大鼠胸主动脉环对PE和KC l收缩张力明显升高(P<0.05)。不同浓度GD对基础张力无明显影响(P>0.05)。在内皮完整主动脉环上,GD预孵育后对KC l收缩张力无明显影响(P>0.05);而16 mg/L GD预孵育后对PE收缩张力有明显抑制作用(P<0.05),此作用可被一氧化氮合酶抑制剂左旋硝基精氨酸甲酯(L-NAME)或鸟苷酸环化酶抑制剂亚甲蓝(MB)所抑制。在去内皮的主动脉环上,不同浓度GD预孵育后对PE收缩张力无显著作用(P>0.05)。结论:GD对高钾血症大鼠胸主动脉环具有内皮依赖性舒张作用,其机制可能与激活血管内皮细胞一氧化氮-鸟苷酸环化酶途径有关。

AIM：To investigate the effects of Ginkgo leaf extract and dipyridamole injection（GD） on the tension of thoracic aorta rings isolated from hyperkalemia rats（HKR）.METHODS：After the model of HKR was established and the preparation of the thoracic aorta rings was made,the tension of the rings was measured by a biological signal analytical system.The thoracic aorta rings were exposed to the medium containing GD at different concentrations and the vaso-constrictive tension was observed after stimulated with phenylephrine（PE） or KCl.RESULTS：Stimulated with PE or KCl,the tension of the thoracic aorta rings in HKR group was significantly higher than that in normal group（P0.05）.GD at the concentrations used in the experiment did not affect the basal tension in the resting rings prepared from both HKR and normal rats.In HKR group,pretreatment of the endothelium-intact thoracic aorta rings with GD at different concentrations showed no significant effect on KCl-induced vessel constriction（P〉0.05）.However,GD at the concentration of 16 mg/L significantly attenuated the vessel constriction induced by PE（P〈0.05）,which was inhibited by the pretreatment with Nω-nitro-L-arginine methylester or methylene blue.GD at different concentrations did not show significantly inhibitory effect on PE-induced tension of endothelium-denuded thoracic aorta rings in HKR group（P〉0.05）.CONCLUSION：GD causes endothelium-dependent relaxation in the thoracic aorta rings of HKR.This effect may be mediated by the nitricoxide-guanylyl cyclase pathway.