Lehmann T N, Gabriel S, Eilers A, Njunting M, Kovacs R, Schulze K, Lanksch W R, Heinemann U
Department of Neurosurgery, Charité Campus Virchow-Klinikum, Humboldt University of Berlin, Germany.
Eur J Neurosci. 2001 Jul;14(1):83-95. doi: 10.1046/j.0953-816x.2001.01632.x.
Neuronal fibres of the hippocampal formation of normal and chronic epileptic rats were investigated by fluorescent tracing methods using the pilocarpine model of limbic epilepsy. Two months after onset of spontaneous limbic seizures, hippocampal slices were prepared and maintained in vitro for 10 h. Small crystals of fluorescent dye [fluorescein (fluoro-emerald) and tetramethylrhodamine (fluoro-ruby)] were applied to different hippocampal regions. The main findings were: (i) in control rats there was no supragranular labelling when the mossy fibre tract was stained in stratum radiatum of area CA3. However, in epileptic rats a fibre network in the inner molecular layer of the dentate gyrus was retrogradely labelled; (ii) a retrograde innervation of area CA3 by CA1 pyramidal cells was disclosed by labelling remote CA1 neurons after dye injection into the stratum radiatum of area CA3 in chronic epileptic rats; (iii) labelling of CA1 neurons apart from the injection site within area CA1 was observed in epileptic rats but not in control animals; and (iv), a subicular-hippocampal projection was present in pilocarpine-treated rats when the tracer was injected just below the stratum pyramidale of area CA1. The findings show that fibre rearrangement in distinct regions of the epileptic hippocampal formation can occur as an aftermath of pilocarpine-induced status epilepticus.
采用荧光示踪法，利用毛果芸香碱诱发的边缘性癫痫模型，对正常大鼠和慢性癫痫大鼠海马结构的神经纤维进行了研究。在出现自发性边缘性癫痫发作两个月后，制备海马切片并在体外保存10小时。将荧光染料[荧光素（荧光祖母绿）和四甲基罗丹明（荧光红宝石）]的小晶体应用于不同的海马区域。主要发现如下：（i）在对照大鼠中，当CA3区辐射层的苔藓纤维束被染色时，颗粒上层没有标记。然而，在癫痫大鼠中，齿状回内分子层的纤维网络被逆行标记；（ii）在慢性癫痫大鼠中，将染料注入CA3区辐射层后，通过标记远处的CA1神经元，揭示了CA1锥体细胞对CA3区的逆行支配；（iii）在癫痫大鼠中观察到CA1区内注射部位以外的CA1神经元被标记，但在对照动物中未观察到；（iv）当示踪剂注射到CA1区锥体细胞层下方时，在毛果芸香碱处理的大鼠中存在下托-海马投射。这些发现表明，毛果芸香碱诱发的癫痫持续状态后，癫痫海马结构不同区域可发生纤维重排。
