Kim Ji-Eun, Kwak Sung-Eun, Choi Hui-Chul, Song Hong-Ki, Kim Yeong-In, Jo Seung-Mook, Kang Tae-Cheon
Department of Anatomy and Neurobiology, College of Medicine, Hallym University, Chunchon, Kangwon-Do 200-702, South Korea.
Neurosci Lett. 2008 Jun 27;438(3):295-9. doi: 10.1016/j.neulet.2008.04.079. Epub 2008 Apr 26.
In the present study, we investigated the distribution of voltage-gated Na(+) channels (VGSCs) in the normal and epileptic hippocampus of gerbils (a genetic epilepsy model) in order to confirm the relationship between VGSC and seizure activity in these animals. There was no difference of VGSC I immunoreactivity in the hippocampus between seizure-resistant (SR) and seizure sensitive (SS) gerbils. VGSC II immunoreactivity was rarely detected in the perikarya of principal neurons and interneurons in the SR gerbil hippocampus. However, in the SS gerbil hippocampus, VGSC II immunoreactivity was densely observed in the somata of interneurons located in the stratum radiatum and stratum lacunosum-moleculare. Double immunofluorescent study showed immunoreactivity for calretinin (approximately 80% in VGSC II-positive neurons) or calbindin D-28k (approximately 20% in VGSC II-positive neurons) in VGSC II-immunoreactive neurons. VGSC II-immunoreactive neurons did not show parvalbumin immunoreactivity. These findings suggest that seizure activity in SS gerbils may be related to the selective hyperactivation of interneurons in stratum lacunosum-moleculare via the up-regulation of VGSC II expression, which leads to the disinhibition of CA1 pyramidal cells.
在本研究中，我们调查了沙土鼠（一种遗传性癫痫模型）正常和癫痫海马中电压门控性钠通道（VGSCs）的分布，以确定这些动物中VGSC与癫痫发作活动之间的关系。抗癫痫（SR）和癫痫敏感（SS）沙土鼠海马中的VGSC I免疫反应性没有差异。在SR沙土鼠海马的主要神经元和中间神经元的胞体中很少检测到VGSC II免疫反应性。然而，在SS沙土鼠海马中，在辐射层和腔隙-分子层中的中间神经元胞体中密集观察到VGSC II免疫反应性。双重免疫荧光研究显示，VGSC II免疫反应性神经元中钙视网膜蛋白（约80%的VGSC II阳性神经元）或钙结合蛋白D-28k（约20%的VGSC II阳性神经元）呈免疫反应性。VGSC II免疫反应性神经元未显示小白蛋白免疫反应性。这些发现表明，SS沙土鼠的癫痫发作活动可能与腔隙-分子层中间神经元通过上调VGSC II表达的选择性过度激活有关，这导致CA1锥体细胞的去抑制。
