颈迷走神经脉冲电刺激对大鼠点燃速度及杏仁核放电的影响

目的　定量研究颈迷走神经刺激对大鼠癫痫形成速度及杏仁核放电的影响。方法　用频率 16 Hz,波宽1.0 ms,串长 10 s,串隔 7min,强度 3.0 m A的恒流脉冲电刺激 18只大鼠的左颈迷走神经 ,同时用强度 0 .4m A的恒流脉冲电诱发刺激大鼠的杏仁核。以 18只仅刺激杏仁核的大鼠作对照 ,观察其癫痫行为及杏仁核放电情况。结果　实验组有 16 / 18只大鼠被点燃 ,对照组有 17/ 18只点燃 ,组间差异无显著性 (P>0 .0 5)。比之于对照组 ,实验组点燃所需杏仁核平均刺激次数及杏仁核平均后放电阈值均显著增高 (P<0 .0 5) ,但杏仁核平均后放电时间两组差异无显著性 (P>0 .0 5)。结论　迷走神经刺激虽最终难以阻断大鼠点燃的发生 ,但可减缓大鼠点燃发生速度 ,提高杏仁核后放电阈值。其抗痫效应可能主要与提高全脑抑制水平 ,抑制痫性放电扩布有关 ,而对痫灶本身放电影响相对较小。

Effects of Stimulating Vagus Nerve with Pulse Current on Speed of Kindling and Afterdischarges of Amygdalas in Rats

Objective To quantitatively study the effects of vagus nerve stimulation (VNS) on the speed of formation of epilepsy and afterdischarges of amygdalas in rats. Methods The left cervical vagus nerves of 18 rats were stimulated with constant squarewave pulse current with intratrain frequencies of 16 Hz,pulse durations of 1 0 ms,train durations of 10s,interstimulus interval of 7 min and intensities of 3 0 mA,whose amygdalas were stimulated with the constant current with intensities of 0 4 mA.The 18 rat with amygdalas stimulated alone were served as control groups.The epileptic behaviour and the discharges of the amygdalas were observed durring the course. Results There were 17 kindling rats in the control group,16 kinding rats in VNS group.There were no significant differences between the two groups ( P>0 05 ).The mean stimulative number of times of amygdalas required for kindling and mean afterdischarge thredshold of amygdalas were significantly increased in the VNS group ( P<0 05 ).but the mean afterdischarge time of amygdalas didn't change markedly ( P>0 05 ). Conclusions Vagus stimulation was difficult to block the triggering of kindling,it could retard the speed of the on set of kindling and raise the thredsholds of amygdala afterdischarges in rats.This phenomenon might relate to raising restraint level in brain and retardding spread of epileptic discharges.VNS could affect the discharges of epileptic focus itself in lesser extent.