目的：观察芒柄花素对兔离体肠平滑肌肌张力的影响并探讨其作用机制。方法采用经典的离体小肠灌流技术，观察芒柄花素对肠平滑肌收缩活动以及乙酰胆碱（ Ach）、氯化钡（ BaCl2）及组胺（ HA）所致痉挛性收缩肠平滑肌的影响。应用 L型钙通道开放剂Bay K8644、肌浆网ryanodine受体阻断剂钌红（ RR）和一氧化氮（ NO）合酶抑制剂左旋硝基精氨酸甲酯（ L-NAME），研究芒柄花素舒张肠平滑肌的作用机制。结果芒柄花素（10、20、40、60、80、100μmol/L）能剂量依赖性的抑制家兔离体小肠平滑肌自发性收缩，对 Ach，HA 和 BaCl2所致的兔离体肠痉挛性收缩也具有剂量依赖性抑制作用，且与无刺激肠平滑肌比较有显著性差异（P＜0.05或P＜0.01）。芒柄花素可明显抑制Bay K8644（0.5μmol/L），阻断RR引起肠平滑肌舒张作用，但L-NAME不能够抑制芒柄花素舒张肠平滑肌作用。结论芒柄花素显著抑制家兔小肠平滑肌的收缩活动，其抑制可能与抑制细胞外钙内流和内钙释放，从而使细胞内钙浓度降低有关，但与小肠平滑肌一氧化氮（ NO）浓度无关。%Objective To observe the influences of formononetin on the contraction of small intestine smooth muscle of rabbits in vitro and explore the mechanism.Methods With the isothermal perfusion of smal 1 intestine vitro , the influences of formononetin on the spontaneous contraction of small intestine and contraction induced by acetylcholine (Ach), histamine(HA) and Bacl2 were observed and the mechanism of formononetin was studied.Results Formononetin reduced the contractivity of small intestine smooth muscle in rabbits in a dose-depended manner.Formononetin could completely block the contraction of Bay K 8644 and nitro-L-arginine methylester ( L-NAME) on the smal1 intestine smooth muscle.It also could block the inhibition of Ruthenium Red ( RR).Conclusions Formononetin inhibits the con-traction of small intestine smooth muscle of rabbits in vitro.The mechanism may be related to inhibits extracellular Ca 2+inflowing via cell membrane and intracellular Ca 2+releasing via sarcoplasmic reticulum.But it has no effect on N 0 concentration in small intestine smooth muscle.
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