葛根素的非内皮依赖性血管舒张作用机制

Endothelium-independent vasorelaxant effect of puerarin on rat thoracic aorta

目的 :研究葛根素对血管的舒张作用并探讨其机制。方法 :记录离体大鼠胸主动脉环张力反应。结果 :葛根素能明显舒张由苯肾上腺素诱导收缩的大鼠主动脉环 ,其血管舒张作用为非血管内皮依赖性 ;KCl预收缩下 ,葛根素对主动脉环无舒张作用。对去内皮的血管环 ,在无Ca2 + 溶液中 ,葛根素不能够抑制咖啡因或苯肾上腺素诱导的短暂收缩。钾通道阻断剂 4 氨基吡啶和四乙胺孵育后能够明显抑制葛根素的舒张血管作用 ,但格列苯脲不能抑制其舒张血管作用。结论 :葛根素的血管舒张作用是非内皮依赖性的 ,其机制可能是通过抑制α肾上腺素受体介导的血管平滑肌细胞外Ca2 + 内流而起作用的。同时 ,KV 通道和ATP敏感性K+ 通道参与了葛根素的舒血管作用。

Objective: To investigate the vasorelaxan t effect of puerarin in rat aortic rings and the mechanism. Method: The isolated thoracic aortic rings of male Sprague-Dawley rats were mounted on the organ bath and the contractile responses of the vessel were recorded. Result: Puerarin completely relaxed the contractions induced by phenylephrine in a concentration-dependent manner in en dothelium-intact and endothelium-denuded rat aorta,but it had no effect on th ose preconstricted by a high concentration of potassium chloride (KCl, 60 mmol ·L -1 ). The relaxant effect of puerarin was significantly inhibited by pr etreatment of endothelium-denuded aorta with potassium channel antagonists tetr aethylammonium,4-aminopyridine but not glibenclamide. Conclusion: Puerarin induces an endothelium-independent relaxation in rat aorti c rings. The mechanisms may involve the reduction in Ca 2+ influx through the calcium channels operated by α-adrenergic receptor and the activation of t he potassium channels (K V and BKca, but not K ATP ). [