杜仲提取物直接或内皮依赖性地引起大鼠血管舒张

目的研究杜仲不同溶剂提取物的舒血管作用并探讨其乙醇提取物的血管舒张机制。方法大鼠胸主动脉环张力测定法。结果在内皮完整血管，杜仲水提物（AQEO）及醇提物（ALEO）均可显著降低PE诱发的血管张力，但醇提物作用显著大于水提物，醇提物的血管舒张活性显著高于其不同溶剂萃取物。杜仲醇提物对去内皮血管的舒张作用显著低于对内皮完整血管。L-N-硝基精氨酸甲酯（L-NAME）、1H-[1，2，4]草酸重氮[4，3-a]喹噁啉（ODQ）、吲哚美辛（INDO）可以显著降低ALEO的舒血管作用（P〈0.05）;四乙氨（TEA）、4-氨基吡啶（4-AP）对ALEO的作用无显著影响，但格列苯脲（glibenclamide）可以明显削弱（P〈0.05）ALEO的血管舒张作用。ALEO对无钙环境下肾上腺素（PE）引起的收缩有显著影响（P〈0.01）。结论杜仲乙醇提取物可以直接或内皮依赖性地引起血管舒张，其机制既与NO，PGI2介导的途径有关，也与其抑制电压依从性钙通道和激活ATP敏感钾通道有关。

The Extracts of Cortex Eucommiae Induces both Directly and Endothelium-dependent Relaxation in Rat Thoracic Aorta

OBJECTIVE To investigate the vasorelaxant effect of different solvent extracts from Cortex Eucommiae and vasorelaxant mechanism of ethanol extract from Cortex Eucommiae.METHODS The effects of Cortex Eucommiae extracts on the contraction of rat thoracic aorta were examined. RESULTS In the endothelium intact aorta ring,both aqueous and ethanol extracts of Cortex Eucommiae significantly relaxed the contraction of aorta rings induced by phenylephrine.Moreover,ethanol extract was more effective than the aqueous extract and different solvent extracts.The relaxation of ethanol extract on the endothelium-denuded aorta ring was significantly lower than on the endothelium intact aorta ring.NG-nitro L-arginine methylester,1H- oxadiazolo quinoxalin-1-one and indomethacin attenuated the effect of ALEO significantly,while tetrathylamonium and 4-aminopyrimide did not.However,glibenclamide attenuated the effect of ALEO significantly.ALEO reduced the contraction elicited by PE in Ca2 free medium.CONCLUSION The ethanol extract of Cortex Eucommiae can induce the relaxation of the aorta ring directly or through endothelium-dependent way.NO and PGI2 may be involved in the endothelium-dependent way,inhibition of voltage-dependent and activation of ATP-sensitive K channel contribute in part to the endothelium-dependent relaxation by ALEO.