Department of Neurology, Ghent University Hospital, Belgium.
Acta Neurol Scand. 2010 Apr;121(4):271-6. doi: 10.1111/j.1600-0404.2009.01223.x. Epub 2009 Dec 10.
The precise mechanism of action of vagus nerve stimulation (VNS) in suppressing epileptic seizures remains to be elucidated. This study investigates whether VNS modulates cortical excitability by determining the threshold for provoking focal motor seizures by cortical electrical stimulation before and after VNS.
Male Wistar rats (n = 8) were implanted with a cuff-electrode around the left vagus nerve and with stimulation electrodes placed bilaterally on the rat motor cortex. Motor seizure threshold (MST) was assessed for each rat before and immediately after 1 h of VNS with standard stimulation parameters, during two to three sessions on different days.
An overall significant increase of the MST was observed following 1 h of VNS compared to the baseline value (1420 microA and 1072 microA, respectively; P < 0.01). The effect was reproducible over time with an increase in MST in each experimental session.
VNS significantly increases the MST in a cortical stimulation model for motor seizures. These data indicate that VNS is capable of modulating cortical excitability.
迷走神经刺激（VNS）抑制癫痫发作的确切作用机制仍有待阐明。本研究通过在 VNS 前后确定皮质电刺激引发局灶性运动性癫痫发作的阈值，来研究 VNS 是否通过调节皮质兴奋性。
雄性 Wistar 大鼠（n = 8）接受左迷走神经周围的袖套电极植入和双侧大鼠运动皮质刺激电极植入。在不同的日子进行两到三次的实验，在标准刺激参数下，分别在 VNS 前和 1 小时 VNS 后评估每个大鼠的运动性癫痫发作阈值（MST）。
与基线值（分别为 1420μA 和 1072μA；P < 0.01）相比，1 小时 VNS 后 MST 整体显著增加。该效果在时间上具有可重复性，每个实验性会议的 MST 均增加。
VNS 在皮质刺激运动性癫痫发作模型中显著增加 MST。这些数据表明，VNS 能够调节皮质兴奋性。
