海马电刺激对耐药性颞叶癫痫大鼠脑细胞GABA（A)受体及钠通道电流的影响

Although several clinical and experimental studies suggested hippocampal stimulation to be effective in pharmacoresistant TLE, the mechanisms underlying the therapeutic effects of hippocampal stimulation in treatment of TLE remain poorly understood.In the present study,the effect of hippocampal stimulation on the spontaneous seizures and kindling stimulus-evoked seizures are observed.Hippocampal GABA content,GABA(A)receptor and the sodium chanel current in rats with phamacoresistant epilepsy are also observed,so as to investigate the mechanism of hippocampal stimulation in the treatment of pharmacoresistant epilepsy.We prepare firstly the amygdala kindling epileptic rat model,and then the pharmacoresistant epileptic rats are selected by testing their response to Phenytoin and Phenobarbital, and they are randomly divided into a hippocampal electrostimulation group A(PES group A) and a pharmacoresistant control group(PRC group).A stimulation electrode was implanted into the hippocampus of all the rats. Low frequency hippocampal stimulation was administered twice per day in the PES group for two weeks. The PRC group receive only sham stimulation.The spontaneous seizurs and stimulus-evoked seizures,as well as the amygdala afterdischarges are used as indexes to observe the effect of hippocampal stimulation.A real-time PCR and Western Blot are used to quantify the GABA(A) mRNA and its protein.A method of high performance liquid chromatography is used to measure the hippocampal GABA content after hippocampal stimulation.A whole-cell recording technique by patch-clamp was used to observe the changes of sodium current of hippocampal pyramidal neurons after the hippocampal stimulation.

多项实验研究以及临床试验表明海马电刺激对颞叶耐药性癫痫有治疗作用，耐药性癫痫患者脑组织中GABA及其受体减少，而进行海马电刺激后可见GABA含量增加，但目前尚不清楚海马电刺激是否通过增加GABA系统的功能而发挥治疗耐药性颞叶癫痫的作用。本研究拟建立耐药性颞叶癫痫大鼠模型，以自发性及诱发性癫痫发作、杏仁核后放电为指标，观察进行病灶侧海马亚急性电刺激治疗并观察海马电刺激的疗效，与此同时检测海马细胞外液GABA浓度及海马细胞GABA受体的标的情况，探讨GABA系统在海马电刺激治疗耐药性颞叶癫痫中的作用。以耐药性癫痫大鼠海马细胞钠离子通道激活曲线、失活曲线、电流-电压曲线、失活后恢复曲线等为观察指标，探讨海马电刺激对耐药性癫痫大鼠脑细胞钠通道电流活性的影响。通过上述研究，为海马电刺激治疗耐药性癫痫的机制探讨积累资料。

国内外研究表明海马电刺激对颞叶耐药性癫痫有治疗作用，耐药性癫痫患者脑组织中γ-氨基丁酸（GABA）及其受体减少，而海马电刺激治疗后可见GABA含量增加，但尚不清楚海马电刺激是否通过增加GABA系统的功能而发挥治疗耐药性颞叶癫痫的作用。.本课题采用多药耐药性颞叶癫痫模型，以癫痫发作的级别及持续时间为行为学指标，以杏仁核后放电阈值（after discharges threshold, ADT）和杏仁核脑电图为疗效观察指标，分析低频海马电刺激(hippocampal low frequency stimulation, Hip-LFS)的治疗效果，并以海马CA1区锥体细胞钠通道电流的变化、海马组织γ-氨基丁酸(GABA)受体表达变化为观察指标，分别采用膜片钳、免疫组化、Western blotting技术等探讨海马电刺激治疗耐药性颞叶癫痫的可能机制。.首次得出结论:.1海马电刺激后耐药癫痫大鼠杏仁核刺激诱发的癫痫发作频率明显减少、发作程度减轻，杏仁核ADT明显延长；.2海马电刺激后脑细胞钠通道活性明显降低，表现为海马刺激组钠通道电流峰值及激活曲线向去极化方向偏移，失活曲线向超极化方向偏移，钠通道失活后恢复时间延长；.3海马电刺激可以抑制钠离子通道电流，其治疗耐药性癫痫的作用可能是通过抑制钠离子通道电流而降低脑细胞兴奋性，从而减少癫痫性电活动的产生而实现的；.4 耐药性颞叶癫痫大鼠海马组织内GABA(A)受体表达明显减少，这可能在耐药性颞叶癫痫的形成过程中发挥部分作用；.5低频海马电刺激能够抑制杏仁核点燃模型的痫性发作和后放电，海马电刺激的抗癫痫作用可能部分是通过增加GABA（B）受体而实现的。