Tamamaki N, Abe K, Nojyo Y
Department of Anatomy, Fukui Medical School, Japan.
Brain Res. 1988 Jun 14;452(1-2):255-72. doi: 10.1016/0006-8993(88)90030-3.
The axonal arborization of single pyramidal neurons in field CA2 and the rostral adjacent area of the rat hippocampus was studied with intracellular staining following the pressure microinjection of horseradish peroxidase (HRP) in combination with the immunoperoxidase technique, and was analyzed three-dimensionally with the aid of a computer system. The axonal arbors were composed of two types of axon branches, which were distinguished as the primary and secondary axon branches on the basis of morphological criteria. The axon branches in the ipsilateral hippocampus exhibited almost the contour of the dorsal hippocampus. The large amount of axon branches labeled with HRP in the stratum (str.) oriens of field CA1 was comparable to that in the str. radiatum of the field. The labeled axon branches in the dorsal hippocampus were not distributed uniformly in terminal regions but were focused on the caudolateral CA1a-b subfields. Most primary axon branches ran to a focus along the alvear fibers. The lamellar organization in the CA2 pyramidal neurons may be composed of axon branches running caudally and terminal branches forming a focus. The dense association fibers along the septotemporal axis may connect the lamellar organized circuits to each other. Axon branches in the septal nuclei of each hemisphere formed a rather flat plane. The commissural fibers of the CA2 pyramidal neurons seemed to form a symmetrical projection field in the contralateral side against the median plane. The axonal arbors and dendritic expansion of the pyramidal neurons shown in this study appeared to reveal the whole image of the single CA2 pyramidal neuron.
采用辣根过氧化物酶（HRP）压力微注射结合免疫过氧化物酶技术，对大鼠海马CA2区及毗邻的吻侧区域单个锥体细胞的轴突分支进行细胞内染色研究，并借助计算机系统进行三维分析。轴突分支由两种类型的轴突分支组成，根据形态学标准将其区分为初级和次级轴突分支。同侧海马中的轴突分支呈现出背侧海马的大致轮廓。CA1区原层中大量被HRP标记的轴突分支与该区域辐射层中的数量相当。背侧海马中标记的轴突分支在终末区域分布并不均匀，而是集中在尾外侧CA1a - b亚区。大多数初级轴突分支沿齿状纤维向一个焦点延伸。CA2锥体细胞中的层状组织可能由向尾侧延伸的轴突分支和形成一个焦点的终末分支组成。沿隔颞轴的密集联合纤维可能将层状组织的回路相互连接。每个半球隔核中的轴突分支形成一个相当平坦的平面。CA2锥体细胞的连合纤维似乎在对侧相对于正中平面形成一个对称的投射区域。本研究中显示的锥体细胞的轴突分支和树突扩展似乎揭示了单个CA2锥体细胞的全貌。
