The Effect Of The Electrical Stimulation Epileptic Foci On The Level Of Glutamate And Gama-Aminobutyric Acid In Hippocampal Of The Kainic Acid-Kindled Rats

【Object】To establish and evaluate the temporal lobe epilepsy(TLE) rat model which kindled by kainic acid(KA),and observe the effects on the behavior and the change of electroencephalogram of the kindled rats whose hippocampal epileptic foci were impacted by high frequency stimulation(HFS). We study the mechanism of the HFS by observing the changes of glutamic acid andγ-amino butyric acid of the extracellular fluid in hippocampus.【Method】1.Seizures were induced in adult male SD rat by KA injection in abdominal cavity to establish the TLE rat model.2.With high frequency stimulation(HFS) of the hippocampal epileptic foci,the study observed seizure characteristics in different stage. The electrophysiological evidence was recorded by video frequency electroen-cephalographic monitoring.3.The changes of glutamic acid andγ-amino butyric acid were detected in hippocampus by microdialysis combined with high performance liquid chromatograph (HPLC).4.To check the position on which the HFS and the probe was put was right or not, the tissue from the chiasm opticum to the hinder of bulla fornicis were para imbedded to observed on pathology.【Results】1.Behavior: The seizure of the rats could be divided clearly into three phases: acute period,silent period and hronic period. The number of time of which the rats of the group which were impacted by high frequency stimulation seizured was decreased than these of the group which were injected KA(p<0.01).The number of seizure time was reduced by 44.51% in HFS group in chronic period.2.The electrophysiological change:①Acute period: There was no changes on the group which were injected normal sodium; there was discontinuous and sporadic spike wave on the model rats.②Silent period: The EEG return approximately normal ,including the little low amplitude of sharp wave,spike slow wave discharges; ③Hronic period: The main characteristic of EEG was paroxysmal spike slow wave, sharp wave discharges in the group which were injected KA, and in the group of HFS, the change of EEG was sporadic spike slow wave and sharp wave.The number of time of which the rats of the group which were impacted by high frequency stimulation epileptic wave was decreased than these of the group which were injected KA(p<0.01).The frency of epileptic wave was reduced by 55.31% in HFS group in hronic period.3.The consequence of detecting the level of Glu and GABA with HPLC:①In every period,the level of Glu in hippocampus of the HFS group was lower than of the groups which were injected KA and were put the rheophore but not impacted(p<0.01),but the level of GABA was no different between the HFS group and other groups (p>0.05).②There was no difference about the level of Glu and GABA in hippocampus between the group which were injected KA and the group which were put the rheophore but not impacted in every period.(p>0.05).4.On the pathology,intraperitoneal injection could lead to neuronal degeneration in the bilateral hippocampus,mainly in the CA1 and hilar area.【Conclusion】1. Estabish the stabile microdialysis combined with high performance liquid chromatograph which defect the Glu and GABA in hippocampus of rats.2.Seizures were induced and to establish the rat epilepsy model with kainic acid (KA) injection in abdominal cavity by stereotactic technique,the model can simulate the human temporal lobe epilepsy(TLE) feature well and is the ideal TLE model.3.HFS of the hippocampal epileptic foci can prevent epileptic seizures to some extent. 4.One of the mechanism of controlling the seizure by HFS is that lowering the level of Glu in focal epileptogenic focus.