不同频率电刺激膈神经导致膈肌肌浆网Ca^(2+)-ATPase和Ca^(2+)释放-摄取动力学改变

Changes in SR Ca^(2+)-ATPase activity, Ca^(2+) release and uptake kinetics of diaphragm muscle after different-frequency chronic electrical stimulation of diaphragmatic nerve

研究不同频率慢性电刺激（ＣＥＳ）后兔膈肌肌浆网（ＳＲ）Ｃａ２＋－ＡＴＰａｓｅ活性以及ＳＲ Ｃａ２＋摄取－释放动力学对不同频率ＣＥＳ的适应性变化。建立不同频率ＣＥＳ组；用定磷法测定ＳＲ Ｃａ２＋－ＡＴＰａｓｅ活性；用Ｆｕｒａ－２荧光法测定ＳＲ Ｃａ２＋摄取－释放动力学。与对照组比较，慢性低频电刺激１０ Ｈｚ和２０Ｈｚ组的ＳＲ Ｃａ２＋－ＡＴＰａｓｅ活性明显降低（Ｐ＜０．０１），Ｃａ２＋释放－摄取动力学也显著降低（Ｐ＜０．０１）；慢性高频电刺激５０ Ｈｚ和１００Ｈｚ组的ＳＲ Ｃａ２＋－ＡＴＰａｓｅ活性则显著升高（Ｐ＜０．０１），Ｃａ２＋释放－摄取动力学亦明显升高（Ｐ＜０．０１）。实验提示，ＣＥＳ后不同频率ＣＥＳ导致膈肌ＳＲＣａ２＋－ＡＴＰａｓｅ、Ｃａ２＋摄取－释放动力学产生不同的适应性变化；对不同功能状态的膈肌应用不同频谱的慢性电刺激可能具有重要的临床意义。

To study adaptation of rabbit diaphragm muscle after different-frequency chronic electrical stimu-lation, Ca2+ -ATPase activity and Ca2+ release-uptake kinetics of sarcoplasmic reticulum (SR) were respec-tively measured by detecting inorganic phosphorus ion and Furo-2 fluorescence. SR Ca2+ -ATPase activity of the low-frequency stimulation group was significantly lower than that of the control group (P <0.01), but it was significantly higher in the high-frequency stimulation group against control (P <0.01). The kinetics of Ca2+ release and Ca2+ uptake was significantly lower in low-frequency group than that of the control (P < 0.01), but the kinetics of Ca2+ release and Ca2+uptake was significantly higher than that of the control (P < 0.01). It is thought that different frequency electrical stimulation induced different adaptative changes in SR Ca2+ -ATPase activity, and Ca2+ release and uptake kinetics of rabbit diaphragm muscle.