MICROANATOMY OF HUMAN EPILEPTIC HIPPOCAMPAL FORMATION

颞叶癫痫(TLE)是成人最常见的癫痫类型 难治性癫痫发作，可通过手术治疗。这个实验室， 美国国立卫生研究院计划研究人类TLE的临床病理， 研究表明：1)使用量化技术，海马区损伤，称为 海马硬化症(HS)是最常见的(65%) 局灶性TLE患者的标准化手术标本。2)HS 包括特定数量和模式的神经元丢失，其相对 对于癫痫的海马区是特异的，在其他疾病中不能重复。 3)HS区与显著的异常轴突萌发有关 和兴奋性苔藓纤维的新突触发生。 抑制GABA系统，特别是在齿状筋膜(FD)。4)尽管 突触的显著细胞丢失、突触的这些区域和突触重组 是癫痫发作时的区域。这些数据导致了这一假设 重新组织的轴突回路，特别是在FD中，是一种机制 用于治疗海马区癫痫发作。这些异常的轴突回路既是 反馈和前馈，可以解释神经元贫乏的区域 会导致癫痫发作。重塑的轴突电路的存在不会 提示突触后受体也有相应的变化 以及它们在新的靶神经元中的mRNAs。为了让FD成为 过度兴奋，应该在数量和类型上有变化 轴突萌发区域的兴奋性和抑制性受体。在 FD，已经假设重组后的MFS在最里面 颗粒上区是谷氨酸能兴奋性的，发芽的GABA 轴突是抑制性的。我们的研究将使用新建立的分子 寡核苷酸探针原位杂交技术 对已建立的免疫细胞化学(ICC)和组织化学的补充 技术，以检验以下可拒绝的假设：1)在 癫痫的FD颗粒上层，萌发反馈的谷氨酸能 MFS将与兴奋性显著不同的增加有关 受体亚型及其mRNAs的上调。2)在相同的 Fd区，GABA终末在颗粒上和 颗粒层将不会显著地与 抑制性GABA受体亚型及其mRNAs。3)颗粒剂 细胞，谷氨酸受体将从Flop到Flip发生基因组变化 (更长的去极化)。我们的方法将客观地衡量和 用图像分析计算机对结果进行量化。结果将是 与尸检和手术标本的海马区进行统计学比较 对于颞叶肿瘤，这是最好的可用对照比较 人体实验。同样重要的是，许多ICC和ISH研究 将在每个人的海马体上尽可能地最大化 患者和生物变量之间的比较，并与 该计划项目的其他子项目。这些研究将提供 对HS的分子病理生理学的洞察和建议 这种形式的难治性局灶性癫痫的发病机制。

Temporal lobe epilepsy (TLE) is the most frequent form of adult intractable seizures and is surgically treatable. This laboratory, studying the clinical pathology of human TLE in our NIH Program Project, has shown that: 1) Using quantified techniques, hippocampal damage, termed hippocampal sclerosis (HS), is the most frequent (65%) finding in standardized surgical specimens from patients with focal TLE. 2) HS comprises a specific amount and pattern of neuron loss that is relatively specific for epileptic hippocampi and is not duplicated in other diseases. 3) The areas of HS are associated with significant aberrant axon sprouting and neosynaptogenesis of the excitatory mossy fibers (MF) and of the inhibitory GABA system, especially in the fascia dentata (FD). 4) Despite the significant cell loss, these ares of HS and synaptic reorganizations are the regions of seizure onsets. These data have lead to the hypothesis that the reorganized axon circuits, especially in the FD, are mechanisms for hippocampal seizure onsets. These aberrant axon circuits are both feedback and feedforward and could explain how an area that is neuron poor can generate seizures. The presence of remodeled axon circuits does not indicate that there are concomitant changes in the postsynaptic receptors and their mRNAs in the new target neurons. In order for the FD to be hyperexcitable, there should be changes in the amount and type of excitatory and inhibitory receptors in the area of axon sprouting. In the FD, it has been assumed that the reorganized MFs in the innermost supragranular region are glutamatergic excitatory, and the sprouted GABA axons are inhibitory. Our research will use newly established molecular techniques of in situ hybridization (ISH) with oligonucleotide probes, in addition to already established immunocytochemical (ICC) and histochemical techniques, to test the following rejectable hypotheses: 1) In the epileptic supragranular layer of the FD, sprouted feedback glutamatergic MFs will relate to significant differential increases in excitatory receptor subtypes along with upregulation of their mRNAs. 2) In the same region of the FD, sprouting of the GABA terminals in the supragranular and granular layers will not significantly relate to increases in the inhibitory GABA receptor subtypes along with their mRNAs. 3) In granule cells, glutamate receptors will have genomic changes from FLOP to FLIP (longer depolarizations). Our methods will objectively measure and quantify the results with an image analysis computer. The results will be statistically compared to autopsies and hippocampi from surgical specimens with temporal tumors, which are the best available control comparisons for human experimentation. Just as importantly, as many ICC and ISH studies will be performed as possible on each human hippocampus to maximize comparisons between patients and biological variables, and compared to other subprojects of the program project. These studies will provide insight into the molecular pathophysiology of HS and suggest important pathogenic mechanisms of this form of intractable focal epilepsy.