芒柄花素舒张家兔离体肠管平滑肌的研究

The mechanism study of formononetin on relaxation of small intestine smooth muscle of rabbits in vitro

目的:探讨芒柄花素舒张家兔离体肠管平滑肌的作用及其机制。方法:采用经典离体肠管平滑肌实验方法,观察不同浓度芒柄花素对对组胺(His),乙酰胆碱(Ach)收缩离体肠管平滑肌量效曲线的影响;用L型钙通道开放剂氟硝尼啶(Bay K8644)、肌浆网ryanodine受体阻断剂钌红(Ruthenium Red,RR)和一氧化氮合酶抑制剂左旋硝基精氨酸甲酯(L-NAME),探讨芒柄花素舒张肠平滑肌的作用机制。结果:不同浓度的芒柄花素(25,50μmol/L)能剂量依赖性地抑制Ach,His收缩离体肠平滑肌的作用,使其量效曲线右移,最大效应降低;亦能抑制L型钙通道开放剂Bay K8644引起的离体肠管平滑肌收缩,大于30μmol/L的芒柄花素作用明显增强(P>0.01)。芒柄花素还能够抑制钌红舒张肠平滑肌的作用,但L-NAME不能够抑制芒柄花素舒张肠平滑肌作用。结论:芒柄花素舒张家兔离体肠管平滑肌的作用与非竞争性抑制M受体和H1受体有关,亦能抑制外钙内流以及内钙的释放作用,但与小肠平滑肌NO浓度无关。

Aim： To explore the mechanism of formononetin on the relaxation of small intestine smooth muscle of rabbits in vitro. Methods： With the isothermal perfusion of smal1 intestine vitro,the influences of formononetin on contraction induced by acetylcholine（ Ach）,histamine（ HA） were studied. And Bay K8644 and Ruthenium Red were used to illustrate the relationship between calcium channel and relaxation of smooth muscle. Results： formononetin reduced the contractivity induced by acetylcholine and histamine of small intestine smooth muscle in rabbits in a dose-depended manner. Formononetin could block the contraction of Bay K8644 and have dramatically effects when its dose was more than 30μmol /L. It also could inhibit the relaxation of Ruthenium Red（ RR）. But Formononetin had no effects on nitro-L-arginine methylester（ L-NAME） in the smal1 intestine smooth muscle. Conclusions： Formononetin inhibits the contraction of small intestine smooth muscle of rabbits in vitro. The mechanism may be noncompetitive inhibition of M-cholinoceptor and H1-receptor. Its effects were related to inhibits extracellular Ca2 ＋inflowing via cell membrane and intracellular Ca2 ＋releasing via sarcoplasmic reticulum. But it has no effect on N0 concentration in small intestine smooth muscle.