电刺激大鼠坐骨神经诱发海马齿状回突触可塑性研究

Synaptic Plasticity in Hippocampus Dentate Gyrus Induced by Electrical Stimulation of Sciatic Nerve

观察电刺激大鼠坐骨神经引起海马齿状回诱发场电位的变化,探讨外周传入信息在海马的可塑性以及海马在痛觉调制中的作用。共记录了28只大鼠海马齿状回诱发场电位,平均幅度(23.73±1.12)μV,潜伏期(198.46±5.91)ms。不同条件刺激引起的反应包括:高频条件刺激使海马齿状回诱发场电位幅度降低;低频条件刺激使海马齿状回诱发场电位幅度增大。结果提示,电刺激坐骨神经可在海马齿状回记录到诱发场电位,不同的条件刺激可引起诱发场电位的不同变化,表现为突触传递效能增强或降低,海马对外周传入信息及痛觉起一定的调制作用。

The present study observed the synaptic plasticity of the evoked field excitatory postsynaptic potentials(fEPSPs) in the hippocampal dentate gyrus in response to sciatic nerve stimulation,a process implicating the hippocampal plasticity rolein pain and other peripheral afferent process modulation.The evoked field potentialsin hippocampus dentate gyrus were recorded in rats.Altogether the evoked fEPSPs (the average amplitude(23.73±1.12)μV;latent period(198.46±5.91) ms )were recorded in 28 rats.The differences in the amplitudes of evoked fEPSPs before and after conditioning stimulation were compared.The changes included synaptic potentiation and synaptic depression;Significant reduction in the amplitudes of the evoked fEPSPs was seen after treating with high frequency conditioning stimulation; the amplitudes of the evoked fEPSPs observed were greater after treating with low-frequency conditioning stimulation.The results suggested that an electric stimulation on the sciatic nerve could evoke fEPSPs in hippocampal dentate gyrus,conditional stimulation could form two synaptic plasticities(i.e. synaptic potentiation and synaptic depression) and the hippocampus could play an important role in the modulation of peripheral afferent processes and pain sensation.