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目的:探讨环氧橙皮油素对平滑肌肌球蛋白功能及肠平滑肌收缩性的影响。方法:在纯化的蛋白体系中进行平滑肌肌球蛋白Ca2+依赖性磷酸化反应,采用甘油聚丙烯酰胺凝胶电泳测定肌球蛋白轻链磷酸化程度,孔雀绿法测定肌球蛋白Mg2+-ATPase活性。以平滑肌肌球蛋白Mg2+-ATPase活性、肌球蛋白磷酸化以及在克氏液中孵育的肠平滑肌收缩振幅为指标,考察环氧橙皮油素对平滑肌肌球蛋白Mg2+-ATPase活性和肌球蛋白磷酸化程度的调节作用,以及环氧橙皮油素对大鼠离体小肠平滑肌收缩性的影响。结果:在肌球蛋白轻链的Ca2+依赖性磷酸化反应中,在40～320μmol·L-1浓度内环氧橙皮油素能抑制磷酸化肌球蛋白Mg2+-ATPase活性及其轻链磷酸化程度(P<0.01),这种抑制作用与1-(5-氯-1-萘-磺酰)-六氢-1,4-二氮杂卓(ML-9)具有协同作用;40～320μmol·L-1浓度内环氧橙皮油素可剂量依赖性抑制大鼠离体小肠平滑肌收缩,且可拮抗新斯的明、乙酰胆碱引起的促进收缩作用,相加阿托品引起的抑制收缩作用(P<0.01)。结论:环氧橙皮油素可通过抑制平滑肌肌球蛋白的功能,抑制胃肠平滑肌的收缩性。
Objective: To investigate the effect of ephedrine on smooth muscle myosin function and intestinal smooth muscle contraction. Methods: Smooth muscle myosin Ca2 + -dependent phosphorylation was performed in purified protein system. The degree of myosin light chain phosphorylation was determined by glycerol polyacrylamide gel electrophoresis. The activity of myosin Mg2 + -ATPase was determined by malachite green assay. The activity of smooth muscle myosin Mg2 + -ATPase, myosin phosphorylation and contraction amplitude of intestinal smooth muscle incubated in Krebs solution were used as indexes to investigate the effect of ephedrine on smooth muscle myosin Mg2 + -ATPase activity and myosin The regulation of phosphorylation and the effect of ephedrine on contractility of isolated rat intestinal smooth muscle. RESULTS: In the Ca2 + -dependent phosphorylation of myosin light chain, within the concentration range of 40-320μmol·L-1, oxyphenolide inhibited phosphorylation of myosin Mg2 + -ATPase and phosphorylation of its light chain (P <0.01). The inhibitory effect was synergistic with 1- (5-chloro-1-naphthalene-sulfonyl) -hexahydro-1,4-diazepine (ML-9) · H-ephedrine could inhibit contractile activity of isolated rat intestinal smooth muscle in a dose-dependent manner and antagonize the effects of neostigmine and acetylcholine on contractile activity and atropine-induced contractile effect (P <0.01). CONCLUSION: Ephedra-oleosin can inhibit the contraction of gastrointestinal smooth muscle by inhibiting the function of smooth muscle myosin.