Copenhaver P F, Taghert P H
Department of Anatomy and Neurobiology, Washington University School of Medicine, Saint Louis, MO 63110.
Development. 1990 May;109(1):17-28. doi: 10.1242/dev.109.1.17.
The enteric plexus (EP) is a major division of the enteric nervous system (ENS) in the moth Manduca sexta and contains a dispersed population of about 360 bipolar neurons, the EP cells. Previously we showed that embryonic EP cells achieve their mature distributions by extensive migration along the gut surface and then display position-specific phenotypes. We now demonstrate that the entire EP cell population is generated from an ectodermal placode that invaginates from the embryonic foregut. Individual EP cells become postmitotic just as they leave the epithelium, but their terminal differentiation is subsequently delayed until after their migratory dispersal. Clonal analysis by injection of lineage-tracing dyes has shown that the EP cell population is derived from a large number of placodal cells, each of which contributes a limited number of neurons to the ENS. Placodally derived clones produce neurons exclusively, while clones arising from cells adjacent to the placode are incorporated into the gut epithelium. These results indicate that neurogenesis in the insect ENS involves a developmental strategy that is distinct from that seen in the insect CNS and which resembles the generation of certain cell classes in the vertebrate nervous system.
肠神经丛（EP）是烟草天蛾中肠神经系统（ENS）的一个主要分支，包含约360个双极神经元的分散群体，即EP细胞。此前我们表明，胚胎期的EP细胞通过沿肠道表面广泛迁移实现其成熟分布，然后表现出位置特异性表型。我们现在证明，整个EP细胞群体由从胚胎前肠内陷的外胚层基板产生。单个EP细胞在离开上皮时就进入有丝分裂后期，但其终末分化随后会延迟，直到迁移分散之后。通过注射谱系追踪染料进行的克隆分析表明，EP细胞群体源自大量基板细胞，每个基板细胞对ENS的神经元贡献数量有限。源自基板的克隆仅产生神经元，而源自基板相邻细胞的克隆则并入肠道上皮。这些结果表明，昆虫ENS中的神经发生涉及一种发育策略，该策略不同于昆虫中枢神经系统中的策略，类似于脊椎动物神经系统中某些细胞类别的产生。
