THE ORGANIZATION OF THE EMBRYONIC AND EARLY POSTNATAL MURINE HIPPOCAMPUS .2. DEVELOPMENT OF ENTORHINAL, COMMISSURAL, AND SEPTAL CONNECTIONS STUDIED WITH THE LIPOPHILIC TRACER DII
THE ORGANIZATION OF THE EMBRYONIC AND EARLY POSTNATAL MURINE HIPPOCAMPUS .2. DEVELOPMENT OF ENTORHINAL, COMMISSURAL, AND SEPTAL CONNECTIONS STUDIED WITH THE LIPOPHILIC TRACER DII
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DOI：
10.1002/cne.903440108
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发表时间：
1994-06-01
影响因子：
2.5
通讯作者：
SORIANO, E
中科院分区：
文献类型：
--
作者：
SUPER, H;SORIANO, E
我们分析了小鼠主要海马传入神经的早期发育。在内嗅皮层注射亲脂性示踪剂1- 1 '-双十八烷基-3，3，3'，3 '-四甲基吲哚羰花青高氯酸盐（DiI）后，在E15海马的白色物质中首次观察到内嗅轴突。E17时，内嗅纤维在腔隙分子层内分叉。在亚成熟期，内嗅轴突形成密集的网络，并被限制在陷窝-分子区的适当终止区。在E19时发现第一个轴突侵入齿筋膜，其密度在后期增加。这些轴突主要存在于外分子层。这种发病的内鼻海马预测证实了注射后的海马逆行标记数据。连合纤维首先进入对侧海马在E18，其数量增加，在以下阶段。连合轴突在海马体中的定向层和辐射层内分叉。在齿状筋膜中，最早的连合纤维出现在P2，终止于分子层的内区和门。我们的结论是，发展中的内嗅和连合的轴突表现出高度的层状特异性，从形成的最早阶段，这是兼容的概念，即不同的子集的早熟神经元填充海马丛状层可能会吸引特定的纤维systems.Hippocamposeptal纤维在E15，在第一隔纤维可以在海马中检测到。这些早期海马隔纤维起源于非锥体神经元，终止于内侧隔区，这是隔传入海马的主要来源。与此相反，隔海马纤维没有看到在海马，直到E17。在围产期，当内侧隔的神经支配变得不那么明显时，前房间隔连接重塑，将轴突发送到背外侧隔区。这个序列表明海马神经元是隔海马连接形成的先驱。(C)1994 Wiley-Liss，Inc.
We have analyzed the early development of the main hippocampal afferents in the mouse. Following injections of the lipophilic tracer 1-1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI) in the entorhinal cortex, entorhinal axons were observed for the first time in the hippocampus at E15, in the white matter. At E17, entorhinal fibers arborized within the stratum lacunosum-moleculare. At sub sequent stages entorhinal axo ns formed dense networks that were restricted to their appropriate termination zone in the lacunosum-moleculare. The first axons invading the fascia dentata were noticed at E19, their density increasing at later stages. These axons were mainly present in the outer molecular layer. This onset of entorhinohippocampal projections was corroborated by retrograde labeling data after injections in the hippocampus. Commissural fibers first entered the contralateral hippocampus at E18, their number increasing at the following stages. Commissural axons arborized within the stratum oriens and radiatum in the hippocampus proper. In the fascia dentata, the earliest commissural fibers were seen at P2, terminating in the inner zone of the molecular layer and in the hilus. We conclude that developing entorhinal and commissural axons show a high degree of laminar specificity from the earliest stages of formation, which is compatible with the notion that distinct subsets of early maturing neurons populating the hippocampal plexiform layers may attract particular fiber systems.Hippocamposeptal fibers develop at E15, before the first septal fibers can be detected in the hippocampus. These early hippocamposeptal fibers originated from nonpyramidal neurons and terminated in the medial septal area, which is the main source of septal afferents to the hippocampus. In contrast, septohippocampal fibers were not seen in the hippocampus until E17. At perinatal stages, the hippocamposeptal connection reshapes, sending axons to the dorsolateral septal area as the innervation of the medial septum becomes less conspicuous. This sequence suggests that hippocampal neurons pioneer the formation of septohippocampal connections. (C) 1994 Wiley-Liss, Inc.