茯苓抑制小肠收缩的作用机制

Study on Mechanism of Poria in Inhibiting Contraction of Small Intestine in vitro

目的:研究茯苓抑制小肠收缩的作用及其机制。方法:采用离体小肠灌流技术,以平均肌张力为指标评价小肠收缩活性。小鼠离体小肠恢复自发收缩后,累积加入茯苓提取液,观察茯苓对离体小肠自发性收缩的影响;分别以乙酰胆碱(acetylcholine,Ach)、氯化钡(BaCl2)和氯化钙(CaCl2)致离体小肠痉挛性收缩,累积加入茯苓提取液,观察茯苓对不同工具药导致的小肠痉挛性收缩的影响;以阿托品(atropine)预孵育离体小肠,观察阻断M受体对茯苓抑制小肠收缩作用的影响;利用分子对接技术将茯苓中的33个化学成分与M胆碱能受体(ID:3UON)进行分子对接,计算结合自由能,进一步从分子层面揭示其作用机制。结果:茯苓能够明显抑制离体小肠自发收缩,抑制Ach、BaCl2、CaCl2所致离体小肠痉挛性收缩;阻断M受体后,茯苓对Ach所致小肠收缩的抑制作用明显减弱;分子对接结果表明,茯苓中齿孔酸、松苓酸A、3-氢化松苓酸等多种成分能够与M受体结合。结论:茯苓抑制离体肠收缩的机制可能与阻断M受体有关,其中齿孔酸、松苓酸A、3-氢化松苓酸可能是茯苓抑制小肠收缩的主要活性成分。

Objective:To elucidate the spasmolytic effect and the underlying mechanism of Poria on small intestine in vitro.Methods:The intestinal perfusion technique was used to evaluate the contractive activity of the small intestinal,which was expressed as the mean muscle tension.Firstly,after regaining spontaneous contraction,the small intestine was incubated with Poria extracts to assess the inhibition of Poria on the spontaneous contraction of the small intestine.Secondly,the spasmolysic effect of Poria on the small intestine were evaluated in the presence of acetylcholine(Ach),BaCl2 and CaCl2,respectively.Then,after blocking the muscarinic(M)receptor with atropine,Poria extracts were added and the relaxing effect was evaluated.In order to investigate the mechanism underlying the relaxing effect,the molecular docking technology was conducted.Thirty-three chemical components in Poria were docked with M receptor(ID:3UON),and the free energy of binding was calculated.Results:Poria was able to inhibit both the spontaneous contraction and spasmodic contraction of the small intestine induced by Ach,BaCl2 or CaCl2.This relaxing effect was attenuated after blocking the M receptor with atropine.The docking results indicated that components in Poria including eburicoic acid,pmicoic acid and 3-hydroxylenic acid were capable of binding to the M receptor to block its function.Conclusion:Poria is capable of inhibiting the small contraction partially through blocking the M receptor.The eburicoic acid,pmicoic acid and 3-hydroxylenic acid may be the primary active constituents for Poria inhibiting the small intestine contraction.