柴胡皂苷A对兔离体小肠平滑肌的舒张作用及其机制

Relaxation Effects of Saikosaponin A on Isolated Rabbit Smooth Muscle and Its Mechanism

目的:探讨柴胡皂苷A(saikosaponin A,SSA)对兔离体小肠平滑肌的舒张作用,探讨其作用机制。方法:采用兔离体小肠平滑肌实验,应用BL-420F生物机能实验系统,观察SSA对正常状态下兔离体小肠平滑肌自发性收缩的影响;使用乙酰胆碱致兔小肠痉挛性收缩后,观察SSA对其痉挛性收缩的影响;应用IP3受体阻断剂肝素和肌浆网ryanodi ne受体阻断剂钌红探讨SSA抑制兔离体小肠平滑肌收缩的作用机制。结果:SSA可剂量依赖性抑制兔离体小肠平滑肌自发性收缩,与给药前比较差异具有统计学意义(P<0.01)。对乙酰胆碱所致兔离体肠痉挛性收缩也具有剂量依赖性抑制作用,差异具有统计学意义(P<0.05)。IP3受体阻断剂肝素能增强SSA舒张兔离体小肠平滑肌的作用(P<0.05),而肌浆网ryanodine受体阻断剂钌红对此无影响(P>0.05)。结论:SSA可抑制兔离体小肠平滑肌收缩,其机制可能与乙酰胆碱竞争,阻断M受体和抑制IP3受体介导的内钙释放有关,但与肌浆网ryanodine受体途径引起的内钙释放无关。

Objective: To explore relaxation effects of saikosaponin A(SSA) on isolated rabbit smooth muscle of rabbit and discuss its mechanism. Methods: The effects of SSA on spontaneous contraction of isolated rabbit smooth muscle of small intestine under normal conditions were observed using the tests on isolated small intestine smooth muscle of rabbit and BL-420 F biological function test system;the effects of SSA on rabbit spasmodic contraction were explored after inducing rabbit spasmodic contraction of small intestine with acetylcholine;the mechanism of SSA inhibiting the contraction of isolated rabbit smooth muscle of small intestine was explored using IP3 receptor blocker heparin(HP) and an antagonist of ryanodine receptor in sarcoplasmic reticulum, ruthenium red(RR).Results: SSA could inhibit spontaneous contraction of isolated rabbit smooth muscle of small intestine in a dose-dependent manner, the difference showed statistical meaning compared with before medication(P<0.05). It possessed the dose-dependent inhibitory effects on spasmodic contraction of isolated rabbit intestine induced by Ach, and the difference showed statistical meaning(P<0.05). IP3 receptor blocker HP could enhance the relaxation effects of SSA on isolated rabbit small intestine smooth muscle(P<0.05), while RR showed no influences on the relaxation effects(P>0.05). Conclusion: SSA could inhibit the contraction of isolated rabbit small intestine smooth muscle, and its mechanism might be related to acetylcholine competition, blocking M receptor and inhibiting the release of IP3 receptor mediated calcium, while not related to the release of intrcellular calcium induced by ryanodine receptor pathway in sarcoplasmic reticulum.