环氧橙皮油素对平滑肌肌球蛋白功能及肌球蛋白轻链激酶表达量的影响

目的 研究环氧橙皮油素对平滑肌肌球蛋白功能及肌球蛋白轻链激酶表达量的影响.方法 考察在钙离子存在的条件下,环氧橙皮油素对20 kDa肌球蛋白轻链的钙离子依赖性磷酸化反应的影响；用孔雀绿法测定环氧橙皮油素对肌球蛋白Mg2+ -ATPase活性的影响；采用蛋白免疫印迹方法考察环氧橙皮油素对平滑肌细胞中肌球蛋白轻链激酶的表达量影响.结果 环氧橙皮油素在20 ～ 320μmol/L范围内剂量依赖性抑制肌球蛋白轻链磷酸化,在5～20 min范围内时间依赖性抑制肌球蛋白轻链磷酸化；在5 ～ 20 min时间范围内,随着环氧橙皮油素用药浓度增加,呈现剂量依赖性抑制肌球蛋白Mg2+ -ATPase活性；在40～ 320 μmol/L范围内剂量依赖性抑制肌球蛋白轻链激酶表达,在0～96 h范围内时间依赖性抑制肌球蛋白轻链激酶表达.结论 环氧橙皮油素可通过抑制平滑肌肌球蛋白功能及肌球蛋白轻链激酶表达量,抑制胃肠道平滑肌的收缩.

Effects of epoxyauraptene on smooth muscle myosin and expression of myosin light chain kinase

AIM To investigate the effects of epoxyauraptene on the function of smooth muscle myosin and the expression of myosin light chain kinase.METOODS The effect of epoxyauraptene on myosin was measured by the use of activities of 20 kDa myosin light chain(LC20) phosphorylation in the presence of Ca2+-calmodulin and the determination of myosin Mg2+-ATPase activity by Malachite green method.The effect of epoxyauraptene on myosin light chain kinase(MLCK) expression was measured by western blot.RESULTS Epoxyauraptene inhibited the phosphorylation of MLCK in the rang of 20-320 μmol/L in dosage response mode at 5-20 min intervals in time response mode,and inhibited myosin Mg2+-ATPase activity at 5-20 min intervals and MLCK expression in the range of 40-320 μmol/L at 0-96 h intervals in time response mode.CONCLUSION Epoxyauraptene could inhibit the gastrointestinal smooth muscle contraction by inhibition of the smooth muscle myosin and MLCK expression.