强直电刺激大鼠海马、中部颞叶新皮质诱发癫癎模型中电振荡与癫癎发生的关系研究(英文)

An investigation on the relations between synchronized oscillations and epileptogenesis induced by repeatedly delivering tetanus into the hippocampus and medial temporal neocortex in rats

在急性、慢性在体大鼠及离体脑片癫疒间 模型上观察 EEG、深部电图、神经元网络及单个神经元的电活动 ,研究中枢同步化电振荡行为在癫疒间发生中的重要作用。实验结果表明 :离体脑片 ( n=40 )上强直电刺激海马 Schaeffer侧枝 ,32 .5% CA1神经元全细胞记录呈现 3～ 1 0 0 Hz膜电位振荡 ,这种电振荡能促进细胞外场电位癫疒间 活动形式的转化。急性癫疒间 模型上 ( n=1 0 ,in vivo) ,反复强直电刺激海马或中部颞叶新皮质可诱发海马区 4～ 7Hz和中部颞叶新皮质 2 0 Hz( n=1 1 )深部电图电振荡。慢性强直电刺激大鼠背侧海马 ( n=1 2 )或中部颞叶新皮质 ( n=1 1 ) ,7～ 8d后出现这些脑区和 EEG电振荡活动的频率及幅度的增加。巨大 EEG节律性电振荡活动成为电图和癫疒间 行为性发作的先兆。说明过度激活海马 -内嗅皮质 -颞叶新皮质产生的同步化电振荡可能是颞叶癫疒间发生的重要原因之一。

To study the functional significance of oscillations in epileptogenesis we observed the relations between synchronized oscillations and epileptic events at the level of EEG,depth electrographes,local neural networks and single neuron in animal experiments in vivo or in vitro.Works were done on three models of epilepsy:kindling model on 400 μm thick horizontal rat brain slices containing the hippocampus(HPC) and entorhinal cortex(EC),acute and chronic epilepsy model in vivo.Tetanus(60 Hz,2 s,0 4～0 6 mA)was used to induce epilepsy events.The results showed that ①In 32 5%(13/40) brain slices both intracellular and extracellular recordings displayed membrane potential oscillations in CA1 neuron at 3～100 Hz induced by electric stimulus into Schaeffer collaterals.These oscillations at 7 Hz were related to synchronous field epileptiform events and promote its conversion.②In acute epilepsy model(n=10) spontaneous oscillations in the HPC at 4～7 Hz or in the medial temporal neocortex (MTNC) at 20 Hz were activated by tetanus into the MTNC or the HPC,respectively.The increased field oscillations could transfer into associated epilepsy events.③In the epileptic rats,the amplitude and frequency of spontaneous oscillations in EEG and depth electrograph were enhanced by chronically stimulating the dorsal HPC(n=12)and MTNC(n=11)respectively.Robust EEG rhythmic oscillations became prediction for behavioral and electrographic seizures in kindled rats.Tetanus induced synchronous oscillations in the HPC MTNC cerebral cortex neural pathway could elicit the generation and development of epilepsy. [