Saito S, Møller A R
Department of Neurological Surgery, University of Pittsburgh School of Medicine, PA 15213.
Neurol Res. 1993 Aug;15(4):225-31. doi: 10.1080/01616412.1993.11740141.
The proximal segment of the facial nerve in rats was stimulated electrically daily for a duration of 2-10 min. After 4-8 weeks of such stimulation, 12 of 18 rats developed abnormal muscle responses that could be demonstrated by recording the electromyographic response from lower face muscles (the mentalis muscle) while the temporal branch of the facial nerve was being stimulated electrically. This abnormal electromyographic response consists of activity that appears in the latency range 6.5-15 ms. In addition, these chronically stimulated rats developed signs of facial synkinesis on the side that had been chronically stimulated. This could be demonstrated by recording electromyographic activity when the blink reflex was being elicited by electrical stimulation of the ophthalmic nerve. Rats in which electrodes had been implanted but which had not been stimulated did not develop any abnormal electromyographic activity. The abnormal electromyographic activity that could be recorded in rats that had been stimulated chronically could not be recorded 4-8 weeks after the stimulation had been terminated. We interpret these results to indicate that chronic electrical stimulation of the facial nerve can render the facial motonucleus hyperactive, and that the signs of this hyperactivity (abnormal muscle response and synkinesis) are similar to those typically seen in patients with hemifacial spasm. We thus presume that these results support the hypothesis that it is the irritation of the facial nerve from a compressing blood vessel that causes the facial nucleus to become hyperactive in patients with hemifacial spasm.
每天对大鼠面神经近端进行2 - 10分钟的电刺激。经过4 - 8周的这种刺激后，18只大鼠中有12只出现了异常的肌肉反应，这可以通过在对面神经颞支进行电刺激时记录下脸部下部肌肉（颏肌）的肌电图反应来证明。这种异常的肌电图反应包括出现在6.5 - 15毫秒潜伏期范围内的活动。此外，这些长期接受刺激的大鼠在长期受刺激的一侧出现了面部联动的迹象。这可以通过在对眼神经进行电刺激引发眨眼反射时记录肌电图活动来证明。植入了电极但未接受刺激的大鼠未出现任何异常的肌电图活动。在长期接受刺激的大鼠中能够记录到的异常肌电图活动在刺激终止4 - 8周后无法再记录到。我们对这些结果的解释是，对面神经的慢性电刺激可使面神经运动核过度活跃，并且这种过度活跃的迹象（异常肌肉反应和联动）与半面痉挛患者中通常所见的相似。因此，我们推测这些结果支持这样一种假说，即血管压迫对面神经的刺激导致半面痉挛患者的面神经核过度活跃。
