慢性VNS对点燃大鼠大脑皮质及海马神经元兴奋性的影响

目的：探讨迷神经刺激（VNS）抗癫痫作用的细胞机制。方法：用戊四氮（PTZ）行大鼠腹空注射点燃制作癫痫模型，行迷走神经刺激抗癫痫，应用荧光分光光度法测定不同浓度谷氨酸（Glu）对正常、PTZ点燃及VNS治疗动物大脑皮质及海马神经元胞内游离钙升高的影响，同时观察VNS对动物癫痫行为的影响。结果：VNS组动物胞内游离钙浓度较PTZ点燃组明显降低，并对外源性Glu的升谪胞内游离钙有明显抑制作用，行为观察显示VNS能明显抑制癫痫发作的严重程度，延长癫痫的发作的潜伏期。结论：VNS能明显抑制大鼠PTZ的点燃效应，降低Glu对神经元胞内游离钙的升高作用。VNS可能通过调节神经元兴奋性／抑制性受体的活性来发挥抗癫痫作用。

The effect of VNS on the L-glutamate-induced augmentation of intracellular free calcium of cortical and hippocampal neurons of PTZ-kindled rats

Objectives:To explore the antiepileptic cellular mechanism of chronic vagus nerve stimulation (VNS). Methods: The rats were kindled by intraperitoneal injection of pentylenetetrazol (PTZ) (45mg/kg weight), and chronic VNS was applied to the kindled rats. The effects of glutamate (Glu) on the intracellular free calcium ([Ca 2+ ]i) of cortical and hippocampal neurons of normal, PTZ kindled and VNS treated rats were examined with fluorescence spectrophotometry respectively. The behavioral changes of all rats were observed. Results: The neuronal [Ca 2+ ]i of the VNS treated rats were significantly lower than that of the PTZ kindled rats. VNS could significantly inhibit the augmentation of neuronal [Ca 2+ ]i induced by Glu. Behavioral changes demonstrated that VNS could significantly reduce the severity and prolong the latency of seizures of PTZ kindled rats. Conclusions: VNS could significantly inhibit the kindling effect of PTZ and reduce the excitability of neurons induced by Glu. VNS might exerted the antiepileptic effects by influencing the activation of neural receptors.