ULTRASTRUCTURAL PLASTICITY OF THE DENTATE GYRUS GRANULE CELLS FOLLOWING RECURRENT LIMBIC SEIZURES .2. ALTERATIONS IN SOMATIC SYNAPSES
ULTRASTRUCTURAL PLASTICITY OF THE DENTATE GYRUS GRANULE CELLS FOLLOWING RECURRENT LIMBIC SEIZURES .2. ALTERATIONS IN SOMATIC SYNAPSES
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DOI：
10.1002/hipo.450040511
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发表时间：
1994-10-01
期刊：
影响因子：
3.5
通讯作者：
GALL, CM
中科院分区：
文献类型：
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作者：
BUNDMAN, MC;GALL, CM
门损伤引起的复发性边缘癫痫发作导致成年大鼠齿状回颗粒细胞上体细胞棘的数量急剧增加。癫痫发作后 3 小时，体细胞棘最多增加，此时许多棘形成突触。目前的定量电子显微镜研究评估了对照和实验性癫痫大鼠的颗粒细胞核周和体细胞棘上存在的突触的数量和类型，目的是确定新形成的体细胞棘是否出现在预先存在的突触部位或与新的神经支配相关。实验大鼠在肺门病变放置后 5 小时（或癫痫发作后 3 小时）处死。在对照组和门损伤 (HL) 大鼠中，可以看到 15-20% 的体细胞棘在单个切片平面内形成突触接触；这些突触几乎都是不对称类型的。随着实验性癫痫大鼠中棘发生率的增加，HL 中棘突触的数量是对照大鼠的 6.25 倍。此外，直接出现在颗粒细胞周核上的不对称突触数量减少了 60%，但不对称突触总数（脊柱加体细胞）没有变化。尽管很少有不对称突触与对照组织中的棘相关，但 60-70% 的不对称突触与实验性癫痫组织中的棘相关。此外，在门损伤大鼠中，深层颗粒层细胞上的对称体细胞突触增加了 20%，导致未治疗大鼠中存在的浅层到深层神经支配梯度的溶解。这些发现支持这样的结论，即由癫痫发作活动诱导的棘在颗粒细胞上预先存在的不对称突触部位形成，并证明短暂的癫痫发作可以迅速引起成人大脑神经支配模式的显着变化。 (C) 1994 年 Wiley-Liss 公司
Hilus lesion-induced recurrent limbic seizures cause a dramatic increase in the numbers of somatic spines on dentate gyrus granule cells in the adult rat. Somatic spines are maximally increased 3 h after the initiation of seizures at which time many of these spines form synapses. The present quantitative electron microscopic study assessed the numbers and types of synapses present on the granule cell perikarya and somatic spines of control and experimental seizure rats with the goal of determining if newly elaborated somatic spines arise at the site of pre-existing synapses or are associated with new innervation. Experimental rats were sacrificed 5 h after hilar lesion placement (or 3 h after seizure onset). In both control and hilus-lesioned (HL) rats, 15-20% of the somatic spines could be seen to form synaptic contacts within a single plane of section; these synapses were almost exclusively of the asymmetric type. With the increased incidence of spines in experimental-seizure rats, there was a 6.25-fold greater number of spine synapses in HL, versus control rats. There was, in addition, a 60% decrease in the number of asymmetric synapses occurring directly on the granule cell perikarya but no change in the total (spine plus somatic) number of asymmetric synapses. Although few asymmetric synapses were associated with spines in control tissue, 60-70% of asymmetric synapses were associated with spines in experimental-seizure tissue. In addition, in hilus lesion rats symmetric somatic synapses were increased by 20% on cells in deep stratum granulosum resulting in a dissolution of the superficial-to-deep innervation gradient present in the untreated rat. These findings support the conclusion that spines induced by seizure activity form at the site of pre-existing asymmetric synapses on the granule cells and demonstrate that brief seizure episodes can rapidly induce marked changes in innervation patterns in the adult brain. (C) 1994 Wiley-Liss, Inc.