Inst. Exp. Med., Hungarian Acad. Sci., H-1083 Budapest, Szigony 43, Hungary.
Epilepsy Res. 2010 Mar;89(1):52-9. doi: 10.1016/j.eplepsyres.2010.01.002. Epub 2010 Feb 11.
Changes of hippocampal GABAergic interneuronal circuits are known to play a central role in epileptogenesis. Fate of functionally different hippocampal interneuron types has been investigated in surgically removed hippocampi of therapy resistant human TLE patients. Perisomatic inhibitory cells containing parvalbumin are responsible for controlling the output of principal cells. Electron microscopic examination revealed that perisomatic innervation of the principal cells was preserved in both sclerotic and non-sclerotic samples, and the ratio of the initial segment synapses increased among the postsynaptic targets, which might give rise to an increased synchrony of granule cell firing. Calbindin-containing dendritic inhibitory cells are well preserved, and they terminate on other interneurons in larger proportion than in the control both in sclerotic and non-sclerotic cases. Substance P receptor-immunopositive cells possessed significantly larger numbers of dendritic branches in the epileptic CA1 region, and the synaptic input of their dendrites has notably increased, whereas the ratio of inhibitory and excitatory synaptic inputs has not changed. Our results suggest that an intense synaptic reorganization takes place in the epileptic hippocampus, including axonal sprouting of certain interneuron types, both in sclerotic and non-sclerotic tissue. Thus, axonal sprouting is a more general phenomenon of TLE than cell loss.
已知海马 GABA 能中间神经元回路的变化在癫痫发生中起着核心作用。在耐药性人类 TLE 患者手术切除的海马中，研究了功能不同的海马中间神经元类型的命运。含有小白蛋白的胞体抑制细胞负责控制主细胞的输出。电镜检查显示，在硬化和非硬化样本中，主细胞的胞体支配均得到保留，并且突触后靶标中的起始段突触的比例增加，这可能导致颗粒细胞放电的同步性增加。钙结合蛋白阳性的树突抑制细胞保存良好，它们在硬化和非硬化病例中都比对照更倾向于终止于其他中间神经元。P 物质受体免疫阳性细胞在癫痫 CA1 区具有明显更多数量的树突分支，并且它们的树突的突触输入显著增加，而抑制性和兴奋性突触输入的比例没有改变。我们的结果表明，在癫痫海马中发生了强烈的突触重组，包括某些中间神经元类型的轴突发芽，在硬化和非硬化组织中均如此。因此，轴突发芽是 TLE 的一种比细胞丢失更普遍的现象。
