Krahl Scott E, Senanayake Shayani S, Handforth Adrian
Neurology Service, VA Greater Los Angeles Healthcare System, and Division of Neurosurgery, University of California, Los Angeles, USA.
Epilepsy Res. 2003 Sep;56(1):1-4. doi: 10.1016/s0920-1211(03)00122-0.
As currently utilized, vagus nerve stimulation (VNS) is applied to the cervical trunk of the left vagus nerve to suppress seizures clinically. Demonstration that VNS can also reduce seizure severity when electrodes are placed on the right cervical vagus nerve in rats would provide empirical evidence that the antiepileptic effects of VNS are not an exclusive property of the left vagus nerve. Rats were implanted with a custom cuff electrode on either the left or right cervical vagus nerve. Two days later, continuous VNS was begun in half the rats with left-sided and half with right-sided electrodes. The remaining rats were connected to the stimulator, but did not receive VNS. After 30s, pentylenetetrazole (PTZ) was administered systemically and seizures were rated by a blinded observer. The PTZ test was repeated two days later, with VNS administered to the previously unstimulated rats, while the others received no stimulation. VNS significantly reduced the severity of PTZ-induced seizures in rats regardless of the side of stimulation as compared to their no-VNS (control condition) seizure severity. No significant differences in efficacy existed based on the side of stimulation. These results indicate that right-sided VNS in rats is just as effective as left-sided VNS, suggesting that fibers necessary for seizure suppression are not unique to the left vagus nerve.
目前，迷走神经刺激（VNS）在临床上是通过作用于左侧迷走神经的颈段来抑制癫痫发作。若能证明在大鼠右侧颈迷走神经上放置电极时VNS也能减轻癫痫发作的严重程度，将为VNS的抗癫痫作用并非左侧迷走神经所特有的这一观点提供实证依据。给大鼠左侧或右侧颈迷走神经植入定制的袖套电极。两天后，对一半左侧电极和一半右侧电极的大鼠开始持续VNS。其余大鼠连接刺激器，但不接受VNS。30秒后，全身给予戊四氮（PTZ），由一位不知情的观察者对癫痫发作进行评分。两天后重复PTZ试验，对之前未接受刺激的大鼠给予VNS，而其他大鼠不接受刺激。与未进行VNS（对照状态）时的癫痫发作严重程度相比，无论刺激哪一侧，VNS均显著降低了大鼠中PTZ诱发的癫痫发作严重程度。基于刺激侧的疗效不存在显著差异。这些结果表明，大鼠右侧VNS与左侧VNS同样有效，这表明抑制癫痫发作所需的纤维并非左侧迷走神经所特有。
