GANGLION FORMATION FROM THE OTIC PLACODE AND THE OTIC CREST IN THE CHICK-EMBRYO - MITOSIS, MIGRATION, AND THE BASAL LAMINA
GANGLION FORMATION FROM THE OTIC PLACODE AND THE OTIC CREST IN THE CHICK-EMBRYO - MITOSIS, MIGRATION, AND THE BASAL LAMINA
复制标题
DOI：
10.1007/bf01744256
复制
发表时间：
1991-01-01
期刊：
影响因子：
--
通讯作者：
MOREST, DK
中科院分区：
文献类型：
--
作者：
HEMOND, SG;MOREST, DK
本文研究了早期鸡胚耳蜗前庭神经节和远侧颅神经节的形态发生。光学显微镜和免疫细胞化学染色纤维连接蛋白和层粘连蛋白被用来跟踪这些神经节的细胞贡献，从耳基板和耳囊。连续半薄塑料切片（3-5 μ m），在每个Hamburger-Hamilton阶段（St.）使用了10到21个。我们能够追踪来自这些上皮结构的单个细胞群进入CVG的原基和颅神经的远端部分。第七、第九和第十神经节。对于免疫染色，使用抗血清来可视化来自St. 14至21胚胎的15 μ m冷冻切片中的基底层。这里首次描述的是耳嵴，一个围绕基板的上皮脊。在耳囊形成期间，细胞从耳嵴（St. 11至14）迁移。这些细胞在空间上与来自鳃上基板和颅神经VII、IX和X的假定神经节的细胞连续。此外，吻侧耳嵴细胞与神经嵴细胞合并，并与新形成的成神经细胞的CVG，从腹侧上皮的耳囊肿在圣14至21。这一区域的上皮形成了CVG的主体，它也比耳囊的其他部分有更多的有丝分裂像。前庭部的细胞最先完成迁移，并将轴突送入髓质和初期的壶腹嵴。纤连蛋白和层粘连蛋白的免疫染色显示，这两个基底细胞相关的糖蛋白出现在一个连续的层下面的耳上皮前CVG迁移。因此，没有证据表明迁移是由基底层的先前分解引起的。从上皮迁移的细胞用其前导突起桥接基底层，而尾随突起从上皮退出。这些拖尾突起在成神经细胞迁移后必须撤回，因为大多数成神经细胞在随后的阶段进行有丝分裂。移行细胞似乎通过在其主导突起之前置换免疫染色的基底层碎片而推出上皮。这表明细胞的外流伴随着上皮本身内部的力量。这是否是由迁移的神经母细胞本身或其他来源产生的仍有待确定。
We have studied the morphogenesis of the cochleo-vestibular (CVG) and distal cranial ganglia in the early chick embryo (White Leghorn embryos). Light microscopy and immunocytochemical staining for fibronectin and laminin were used to trace the cellular contributions to these ganglia from the otic placode and otocyst. Serial semi-thin plastic sections (3-5-mu-m) stained with toluidine blue at each Hamburger-Hamilton stage (St.) from 10 to 21 were used. We were able to trace individual groups of cells derived from these epithelial structures into the anlagen of the CVG and the distal parts of cranial n. ganglia VII, IX, and X. For immunostaining, antisera were used to visualize the basal lamina in 15-mu-m cryostat sections from St. 14 to 21 embryos. Described here for the first time is the otic crest, a ridge of epithelium surrounding the placode. Cells migrate from the otic crest (St. 11 to 14) during the period when the otocyst is forming. These cells become continuous spatially with those derived from the epibranchial placodes and the presumptive ganglia of cranial nerves VII, IX, and X. Furthermore, rostral otic crest cells merge with neural crest cells, which appose the myelencephalon, and they join with the newly formed neuroblasts of the CVG, which migrate from the ventral epithelium of the otocyst at St. 14 to 21. This region of the epithelium forms the bulk of the CVG; it also has many more mitotic figures than the rest of the otocyst. Cells in the rostralmost CVG (vestibular part) are the first to complete their migration and send axons into both the medulla and incipient crista ampullaris. Immuno-staining for fibronectin and laminin shows that these two basallamina-associated glycoproteins appear in a continuous layer beneath the otic epithelium just prior to CVG migration. Thus there is no evidence that the migration is launched by a prior decomposition of the basal lamina. The cells migrating from the epithelium bridge the basal lamina with their leading processes while the trailing processes are withdrawing from the epithelium. These trailing processes must withdraw after the neuroblast migrates, since most of the neuroblasts undergo mitosis in subsequent stages. The migrating cells appear to push out of the epithelium by displacing immunostained fragments of the basal lamina ahead of their leading processes. This suggests that the exodus of cells is accompanied by forces within the epithelium itself. Whether this is generated by the migratory neuroblasts themselves or by other sources remains to be determined.