Effect of local cooling on excitation-contraction coupling in myasthenic muscle: Another mechanism of ice-pack test in myasthenia gravis.
Effect of local cooling on excitation-contraction coupling in myasthenic muscle: Another mechanism of ice-pack test in myasthenia gravis.
复制标题
局部冷却对肌无力肌肉兴奋-收缩耦合的影响：重症肌无力冰袋试验的另一种机制。
DOI：
10.1016/j.clinph.2017.08.030
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发表时间：
2017
期刊：
影响因子：
--
通讯作者：
Shimohama S.
中科院分区：
文献类型：
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作者：
Yamamoto D;Imai T;Tsuda E;Hozuki T;Yamauchi R;Hisahara S;Kawamata J;Shimohama S.
冰袋测试是一种方便的诊断重症肌无力（MG）的测试程序。我们调查的潜在机制的冰袋测试进行双边masseters.MethodsWe三叉神经重复刺激（RNS），兴奋-收缩（E-C）耦合评估（今井的方法）和咬合力测量之前和冷却后的MG患者和正常对照组的咬肌。放置冰袋上的咬肌3分钟后，三个测试的连续记录进行了不同的时间间隔，在10分钟后cooling.ResultsThe咬合力增加显着冷却后，在冰袋阳性MG患者。与冰袋阴性患者和正常对照组相比，冰袋阳性MG患者的咬肌冷却后下颌运动的加速度和加速度比（在给定时间的加速度与基线加速度）显著增加。冷却的长期效果持续到记录结束，即使递减响应RNS已恢复到基线value.ConclusionsCooling的肌无力肌肉可能会引起两种效果。一种是对终板电突触传递的短期效应，另一种是对肌肉E-C偶联的长期效应。
ObjectiveThe ice-pack test is a convenient diagnostic testing procedure for myasthenia gravis (MG). We investigated the underlying mechanism of the ice-pack test performed on bilateral masseters.MethodsWe performed trigeminal repetitive nerve stimulation (RNS), excitation-contraction (E-C) coupling assessment (Imai’s method) and bite force measurement before and after cooling of the masseters in MG patients and normal controls. After placing the ice-pack on the masseters for 3 min, serial recordings of the three tests were performed at various time intervals during 10 min after cooling.ResultsThe bite force increased significantly after cooling in ice-pack-positive MG patients. The acceleration and acceleration ratio (acceleration at a given time to baseline acceleration) of jaw movement increased significantly after cooling of the masseters in ice-pack-positive MG patients compared to ice-pack-negative patients and normal controls. The prolonged effect of cooling continued until the end of recording even though decremental response to RNS had returned to baseline value.ConclusionsCooling of myasthenic muscle may induce two effects. One is relatively short effect on electrical synaptic transmission at the endplate, and another is prolonged effect on E-C coupling in the muscle.SignificanceThe ice-pack test induces a prolonged effect of ameliorating impaired E-C coupling in MG.