经颅磁及电刺激运动诱发电位监测大鼠脊髓功能

Motor evoked potentials from transcranial magnetic or electric stimulation for monitoring of rat spinal cord furction

目的 检测大鼠磁刺激运动诱发电位 (MEP)与电刺激MEP信号的正常值 ,比较两者在刺激方式、信号特征和临床意义等方面的异同。方法 2 0只雄性SD大鼠经静脉麻醉后采用Mag 2型磁刺激仪和Cantada型肌电图仪分别进行单次经颅磁及电刺激 ,观察不同刺激强度下 ,在T12 硬膜外和双侧前肢伸肌和后肢腓肠肌记录的MEP变化特征。结果 磁刺激scMEP先正后负 ,以P1和N1波最显著 ,波形不够稳定 ,个体间差异较大 ,随着刺激强度增大 ,MEP潜伏期缩短 ,波幅增大。近阈值电刺激MEP与相应的超强磁刺激MEP潜伏期相近 ,波幅也相差不大。结论 采用单次磁或电震刺激MEP仍能客观反映脊髓运动传导束的功能状态 ,电和磁刺激MEP之间存在一定程度的同源成份 ,可以作为临床与动物实验比较研究的依据。

Objective To determine the normal values of motor evoked potentials (MEP) in rats elicited by transcranial magnetic or electric stimulation, and to compare the stimulation parameters,the signal characteristics and the clinical implication of them.Method During intravenous anesthesia,20 male SD rats received single transcranical magnetic and electric stimulation with Mag2 stimulator and Cantada electromyograph.The characteristics of MEP recorded epidurally or in the extensor muscles of bilateral forelimbs and gastrocnemius muscles of hindlimbs under different intensity stimulation were observed.Result Magnetic MEP consisted of positive peaks followed with negative peaks,among which the P 1 or N 1 were remarkable.It had unstable waveform and great individual variance.Its latency decreased and its amplitude increased with increasing stimulation intensity.The latency and amplitude of MEP elicited by near-threshold electric stimulation were similar to those of MEP evoked by super-intensive magnetic stimulation.Conclusion MEP elicited by single magnetic or electric stimulation can reflect the functional status of the motor tracts in the spinal cord.Some co-origin components exist between electric MEP and magnetic MEP,which can be used as the comparative foundation for the clinical and experimental researches.