THE DEVELOPMENT OF THE DENTATE AREA AND THE HIPPOCAMPAL MOSSY FIBER PROJECTION OF THE RAT
THE DEVELOPMENT OF THE DENTATE AREA AND THE HIPPOCAMPAL MOSSY FIBER PROJECTION OF THE RAT
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DOI：
10.1002/cne.902410204
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发表时间：
1985-01-01
影响因子：
2.5
通讯作者：
GAARSKJAER, FB
中科院分区：
文献类型：
--
作者：
GAARSKJAER, FB
本文应用荧光示踪、尼氏染色和Timm ′ s组织化学方法，在光镜水平上观察了大鼠海马齿状回和海马苔藓纤维系统的发育。虽然齿状颗粒层的细胞结构发育主要是出生后的现象，但初始事件发生在出生前。颗粒层中细胞的聚集和成熟从外侧到内侧，从表层到深层以分级的方式进行。最早形成的颗粒细胞可能直接来源于室区细胞。它们在出生前就开始形成苔藓状纤维，要么是在相对较长的迁移到颗粒层的过程中，要么是在它们到达后不久。然而，大多数颗粒细胞来自于门部的次级增殖中心。它们在出生后一段时间到达颗粒层后开始产生苔藓状纤维。颗粒细胞的总补体开始生长苔藓状纤维，其顺序与颗粒层内原始细胞的最终位置有关。该顺序也以分级的方式从外侧到内侧以及从层的表面到深层进行。在开始时，苔藓状纤维相对快速地伸长。在出生时，Timm染色的苔藓纤维区已经占据了门的前外侧部分和邻近的下区的上锥体部分。一旦苔藓纤维到达下区的远端，它们就沿着海马体的纵轴沿着得更慢。与此同时，生后第一周，苔藓纤维区的Timm-Doppler向上级区域变弱，发展成一种成熟的模式，其中苔藓纤维区的远端部分染色最强烈。在整个发育过程中，来自首先形成的颗粒细胞的纤维比来自后来形成的颗粒细胞的纤维更长，并且在隔颞维度上分歧更大。与其他轴突系统，似乎是雕塑从一个弥漫的连接，这里提出的结果提供的证据表明，苔藓纤维系统的地形关系的逐步发展。
The development of the dentate area and the hippocampal mossy fiber system of the rat has been investigated at the light microscopic level by using fluorescent tracing, Nissl, and Timm''s histochemical methods. Although the cytoarchitectonic development of the dentate granular layer is mainly a postnatal phenomenon, the initial events take place before birth. The aggregation and maturation of the cells in the granular layer proceed in a graded fashion from the lateral to the medial and from the superficial to the deep aspects of the layer. The earliest-formed granule cells are probably derived directly from the cells of the ventricular zone. They start to form mossy fibers prenatally, either during the relatively long period of migration to the granular layer or soon after their arrival. However, most of the granule cells are derived from a secondary proliferative center in the hilus. They start to produce mossy fibers postnatally a while after arriving at the granular layer. The total complement of granule cell starts to grow mossy fibers in a sequence that is related to the final position of the cells of origin within the granular layer. This sequence also proceeds in a graded fashion from the lateral to the medial and from the superficial to the deep aspects of the layer. In the beginning the mossy fibers elongate relatively rapidly. Already at birth the Timm-stained mossy fiber zone occupies the anterolateral part of the hilus and the adjacent suprapyramidal parts of the regio inferior. Once the mossy fibers have reached the distal end of the regio inferior they elongate along the longitudinal axis of the hippocampus more slowly. At the same time the Timm-stainability of the mossy fiber zone, which, during the first postnatal week, is weaker toward the regio superior, develops a mature pattern in which the distal part of the zone stains most intensely. Throughout development, fibers from the granule cells that form first are longer and diverge more in the septotemporal dimension than fibers from later-forming granule cells. In contrast to other axonal systems which appear to be sculptured from a diffuse set of connections the results presented here provide evidence that the topographic relationships of the mossy fiber system develop in a stepwise fashion.