【摘要】 目的:探讨植物雌激素美皂异黄酮舒张血管的可能机制。方法:采用MedLab生物信号采集系统记录灌流大鼠胸主动脉环张力变化。结果:美皂异黄酮(10-9~10-4mol/L)对苯肾上腺素(PE,10-5mol/L)预收缩的内皮完整或去内皮血管环均产生浓度依赖性的舒张作用;美皂异黄酮对高浓度氯化钾(KCl,6×10-2mol/L)预收缩的血管环也产生浓度依赖性的舒张作用;四乙胺(TEA,5×10-3mol/L)或格列苯脲(3×10-6mol/L)预处理对美皂异黄酮诱导的去内皮动脉环舒张作用具有明显的抑制效应;在无钙液中,美皂异黄酮抑制PE引起的去内皮主动脉环的短暂收缩。结论:美皂异黄酮的非内皮依赖性血管舒张作用的机制可能涉及血管平滑肌细胞的Ca2+激活K+通道和ATP敏感性K+通道的激活,以及肌浆网内钙离子释放的减少。更多还原

【Abstract】 Aim: To investigate the mechanisms of vasodilatation of plant-derived estrogen biochanin A.Methods: Isolated aortic ring preparations from Sprague-Dawley rats were suspended in individual organ baths.The tension was measured isometrically.Results: Biochanin A at the range of 10^-9～10^-4 mol/L provoked concentration-dependent and endothelium-independent relaxation of the rings constricted by phenylephrine(10^-5 mol/L).Biochanin A caused concentration-dependent relaxation of denuded rings preconstricted with KCl(6×10^-2 mol/L).Glibenclamide(3×10^-6 mol/L),a selective inhibitor of ATP-sensitive potassium channels,and tetraethylammonium(5×10^-3 mol/L),a Ca²⁺-activated K⁺ channel inhibitor,significantly attenuated the relaxation induced by biochanin A.The vasoconstriction induced by phenylephrine was decreased by biochanin A in Ca²⁺-free medium. Conclusion: The endothelium-independent relaxation of thoracic aorta induced by biochanin A might be mediated by ATP-sensitive K⁺ channels,Ca²⁺-activated K⁺ channels and intracellular Ca²⁺ release from sarcoplasmic reticulum.更多还原