Correlation of bite force with excitation-contraction coupling time of the masseter in myasthenia gravis
Correlation of bite force with excitation-contraction coupling time of the masseter in myasthenia gravis
复制标题
重症肌无力咬合力与咬肌兴奋收缩耦合时间的相关性
DOI：
10.1016/j.clinph.2010.01.036
复制
发表时间：
2010
影响因子：
4.7
通讯作者：
Shimohama S
中科院分区：
文献类型：
--
作者：
Tsuda E;Imai T;Hozuki T;Yamauchi R;Saitoh M;Hisahara S;Yoshikawa H;Motomura M;Shimohama S
为探讨重症肌无力（MG）患者咬肌兴奋-收缩（E-C）偶联受损与咬合力的关系，采用针电极刺激三叉神经运动神经，同时记录20例MG患者咬肌复合肌动作电位（CMAP）和下颌运动相关电位（MRP）。根据CMAP和MRP的潜伏期差异计算E-C耦合时间（ECCT）。使用压敏片测量咬合力。在皮质类固醇单独治疗或与FK 506、环孢素A、静脉注射免疫球蛋白和免疫吸附剂的各种组合治疗前后，对咬肌重复神经刺激（RNS）、ECCT和咬合力的下降百分比进行了系列评估。简单回归分析表明，%减量、ECCT和咬合力之间存在线性相关。然而，ECCT缩短伴随咬合力恢复没有减少% decrease观察在4 patients. CONCLUSIONSMAsteric E-C耦合受损，在一些MG患者，和功能恢复的E-C耦合至少部分有助于增加治疗后的咬合力。
OBJECTIVEThe aim of this study was to elucidate the relationship between the impairment of excitation–contraction (E–C) coupling of masseter and the bite force in patients with myasthenia gravis (MG).METHODSIn 20 patients with MG, masseteric compound muscle action potential (CMAP) and mandibular movement-related potentials (MRP) were recorded simultaneously after stimulating the trigeminal motor nerve with a needle electrode. The E–C coupling time (ECCT) was calculated by the latency difference between CMAP and MRP. Bite force was measured using a pressure-sensitive sheet. Serial assessments of % decrement in masseteric repetitive nerve stimulation (RNS), ECCT, and bite force were performed before and after corticosteroid therapy alone or in various combinations with FK506, cyclosporin A, intravenous immunoglobulin and immunoabsorption.RESULTSPercent amplitude decrement in RNS and ECCT decreased significantly accompanying an increase in bite force after treatment. Simple regression analysis demonstrated a linear correlation among % decrement, ECCT and bite force. However, ECCT shortening accompanying bite force recovery without reduction in % decrement was observed in 4 patients.CONCLUSIONSMasseteric E–C coupling is impaired in some MG patients, and functional recovery of E–C coupling contributes at least in part to the increase in bite force after treatment.SIGNIFICANCEImpaired E–C coupling contributes to muscle weakness in patients with MG.