Balaskas C, Gabella G
Department of Anatomy and Developmental Biology, University College London, Gower Street, London, WC1E 6BT, UK.
Brain Res. 1998 Sep 7;804(2):275-83. doi: 10.1016/s0006-8993(98)00709-4.
We examined by immunohistochemistry the expression of glial fibrillary acidic protein (GFAP) in enteric ganglia of the chick embryo, using a polyclonal antibody. The morphology of enteric ganglion cells was examined by electron microscopy. Faint GFAP immunoreactivity was detected in ganglion cells and cell processes from around day 7 in ovo. Later in development the intensity of the immunofluorescence increased and it became more evident that immunoreactive small ganglion cells (interpreted as primitive glial cells), and their processes, surrounded larger negative cell profiles (interpreted as primitive neuronal cells); GFAP immunofluorescence was also evident in intramuscular and mucosal nerve trunks. In colocalization experiments, GFAP immunoreactivity was detected in a proportion of HNK-1/N-CAM immunoreactive ganglion cells, in both the myenteric and submucosal plexus. In addition, we observed GFAP immunoreactive nerves in wholemount preparations of chick gut from as early as day 4.5 in ovo. In the ganglionated nerve of Remak, GFAP immunoreactive satellite and Schwann cells were in evidence from day 5 of incubation. Neuronal markers, such as neurofilament, have been detected very early in development in neural crest cell populations in chick enteric ganglia. In contrast, the expression of markers of the glial phenotype has previously been observed only in the late stages of embryonic development. From our experiments, we conclude that neuronal and glial phenotypes are immunohistochemically distinct from as early as day 4.5 of incubation, even if by ultrastructural criteria glial cells are clearly distinguishable from neurons only after day 16 in ovo.
我们使用多克隆抗体，通过免疫组织化学方法检测了鸡胚肠神经节中胶质纤维酸性蛋白（GFAP）的表达。通过电子显微镜检查了肠神经节细胞的形态。在胚胎发育约7天时，在神经节细胞和细胞突起中检测到微弱的GFAP免疫反应性。在发育后期，免疫荧光强度增加，更明显的是，免疫反应性小神经节细胞（被解释为原始胶质细胞）及其突起围绕着较大的阴性细胞轮廓（被解释为原始神经元细胞）；GFAP免疫荧光在肌内和粘膜神经干中也很明显。在共定位实验中，在肌间神经丛和粘膜下神经丛中，一部分HNK-1/N-CAM免疫反应性神经节细胞中检测到了GFAP免疫反应性。此外，我们早在胚胎发育4.5天时就在鸡胚肠道的整装标本中观察到了GFAP免疫反应性神经。在雷马克神经节化神经中，从孵化第5天起就有GFAP免疫反应性卫星细胞和施万细胞。神经元标记物，如神经丝，在鸡胚肠神经节的神经嵴细胞群体发育早期就已被检测到。相比之下，胶质细胞表型标记物的表达以前仅在胚胎发育后期被观察到。从我们的实验中，我们得出结论，早在孵化第4.5天时，神经元和胶质细胞表型在免疫组织化学上就有明显区别，即使根据超微结构标准，胶质细胞在胚胎发育16天后才明显区别于神经元。
