论文标题:皮质发育障碍大鼠海马神经元钠通道和钙通道功能的变化
Function of Voltage-dependent Sodium Channel and HVA Calcium Channel on Hippocampal Neurons from Rats of Cortical Dysplasia
论文作者
论文导师 肖波,论文学位 博士,论文专业 神经病学
论文单位 中南大学,点击次数 74,论文页数 92页File Size3330K
2006-05-01论文网 http://www.lw23.com/lunwen_55157832/
disorders of cortical development; epilepsy;voltage-dependent sodium channel; high voltage-activated calcium channel
研究背景 大脑皮质发育障碍(DCDs)是一组由多种原因引起的中枢神经系统发育异常性疾病，以多种形式的癫痫发作为主要临床表现，是难治性癫痫的主要病因之一。以往的研究主要注重发育异常组织中神经元的形态学改变，但它们的功能改变却知之甚少。采用给孕鼠腹腔注射卡莫司汀(BCNU)的方法可制作广泛型皮质发育障碍模型，组织学显示皮质层状结构消失，海马CA1区形成灰质异位结节，这些病理改变易引起神经元的过度兴奋，导致癫痫易感性增高。我们通过建立BCNU致皮质发育障碍模型，运用全细胞膜片钳技术记录海马CA1区神经元电压依赖性钠电流和高电压激活型(HVA)钙电流，并与正常大鼠海马CA1区神经元进行比较，以期发现钠、钙离子通道改变在皮质发育障碍性癫痫形成中的作用。 研究方法 1．制作皮质发育障碍模型。6只妊娠SD大鼠于E15天腹腔注射BCNU20mg／kg，所产仔鼠入模型组；另6只SD孕鼠于E15天腹腔注射相应剂量5％葡萄糖水溶液，所产仔鼠入对照组。2．Nissl染色检查模型皮质和海马结构的病理改变。3．观察两组大鼠日常活动能力变化。4．于P40天对两组大鼠进行脑电图记录。5．用低于常规致痫剂量的氯化锂—匹罗卡品诱导癫痫发作，比较皮质发育障碍模型组和正常对照组大鼠癫痫发作的潜伏期、癫痫持续时间和死亡率。6．急性分离大鼠海马CA1区神经元，运用全细胞膜片钳技术记录电压依赖性钠电流和HVA钙电流，并将皮质发育障碍模型组与对照组进行比较。 研究结果 1．皮质发育障碍模型组大脑体积明显减小，脑湿重低于正常对照组(P＜0.05)，病理切片可见大脑皮质变薄，皮质层状结构紊乱，海马锥体细胞排列稀疏，CA1区和CA2区出现结节状灰质异位团块。2．皮质发育障碍模型鼠日常活动能力减弱，但未见自发性癫痫发作。3．皮质发育障碍模型鼠脑电图以低波幅β节律为主，未
Background Disorders of cortical development (DCDs) resulting from aberrant brain development are often associated with several forms of epilepsy and characteristic of medically intractable epilepsy. Although the morphological properties of neurons within these malformations are well understood, very little is known about the function of these neurons. In rats, prenatal carmustine (BCNU) exposure produces loss of lamination in cortical structures and distinct nodular heterotopia, which are prone to hyperexcitability of neurons and may contribute to the increased seizure susceptibility observed in these animals. To study the electrophysiology of dysplastic cortex, we developed an experimental model of DCDs by BCNU-exposure and investigated the changes in properties of voltage-dependent sodium current and high voltage-activated (HVA) calcium current and their epileptogenic mechanisms.Methods 1. The animal models of DCDs were established by BCNU-exposure in uterus. Six pregnant Sprague-Dawley rats were injected intraperitoneally with 20mg/kg of BCNU on embryonic day 15(E15), their pups were enrolled in model group. Another six were injected with a corresponding volume of 5% dextrose in water on E15, their offspring were taken as control. 2. Histological changes of cerebral cortex and hippocampus were detected by cresyl violet staining. 3. Daily activities of rats were observed. 4. EEG recordings were carried on P40. 5.Rats were induced seizures by Lithium Chloride-Pilocarpine intraperitoneal injection with a lower dose than routine. The latency and duration of seizure onset and mortality of two groups were compared. 6.Voltage-dependent sodium currents and HVA calcium currents were recording in acutely isolated CA1 pyramidal neurons using the whole-cell patch-clamp technique. We analyzed their properties and compared with
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