Stratum radiatum giant cells:: a type of principal cell in the rat hippocampus
Stratum radiatum giant cells:: a type of principal cell in the rat hippocampus
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DOI：
10.1046/j.1460-9568.1998.00402.x
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发表时间：
1998-12-01
影响因子：
3.4
通讯作者：
Freund, TF
中科院分区：
文献类型：
--
作者：
Gulyás, AI;Tóth, K;Freund, TF
已发现大鼠海马 CA1 区放射层中不同类型的神经元表达长时程增强的直接细胞形式 (LTP, Maccaferri & McBain, 1996, J. Neurosci. 16, 5334)，但它们的功能特性，即中间神经元还是主细胞，仍然未知。体外海马切片的全细胞记录与光学和电子显微镜相结合来回答这个问题。 LTP 通过配对方案强烈诱导，并使用含有生物胞素的移液器测量辐射巨细胞 (RGC) 的生理特性。细胞树突和轴突乔木的重建揭示了与 CAI 锥体细胞相似的形态特性，但存在一些特征差异。它们通常有两个大直径的顶端树突，或者当只有一个树突出现时，它很快就会分叉。顶端树突在分子空隙层中形成树突簇，并且树突（而不是胞体）被传统的刺密集覆盖。轴突从体体的基极发出，下降到东方层，并发出几个带有水平行进的侧支的轴突末端，保留在东方层中。主要的有髓轴突干转向菌毛。在电子显微镜下，发现轴突末端在突触后树突轴和层方向的树突棘上形成不对称的突触。树突接收不对称的突触，主要在它们的刺上。轴突初始片段还接收了几个突触，这是在中间神经元上从未观察到的特征。所有上述特征都支持RGCs是兴奋性主要神经元的结论。
Neurons of a distinct type in CA1 area stratum radiatum of the rat hippocampus have been found to express a direct cellular form of long-term potentiation (LTP, Maccaferri & McBain, 1996, J. Neurosci. 16, 5334), but their functional identity, i.e. whether interneuron or principal cell, remained unknown. Whole cell recording from hippocampal slices in vitro was combined with light and electron microscopy to answer this question. LTP was robustly induced by a pairing protocol and physiological properties were measured in radiatum giant cells (RGCs) using biocytin containing pipettes. Reconstruction of the cells' dendritic and axonal arbor revealed morphological properties similar to CAI pyramidal cells with some characteristic differences. They typically had two large diameter apical dendrites, or when only one dendrite arose, it soon bifurcated. Apical dendrites formed a dendritic tuft in stratum lacunosum-moleculare and the dendrites, but not the somata, were densely covered with conventional spines. The axon arose from the basal pole of the soma, descended to stratum oriens and emitted several axon terminals bearing collaterals that travelled horizontally, remaining in stratum oriens. The main, myelinated axon trunks turned towards the fimbria. In the electron microscope axon terminals were found to form asymmetrical synapses on postsynaptic dendritic shafts and dendritic spines in stratum oriens. The dendrites received asymmetrical synapses, mostly on their spines. The axon initial segments also received several synapses, a feature never observed on interneurons. All the above characteristics support the conclusion that RGCs are excitatory principal neurons.