Hall A K, Landis S C
Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, OH 44106.
J Neurocytol. 1992 Sep;21(9):635-47. doi: 10.1007/BF01191725.
While distinct precursors committed to a neuronal or glial cell fate are generated from neural crest cells early in peripheral gangliogenesis, little is known about the subsequent generation and maturation of young satellite glia from restricted glial precursor cells. To examine the division and migration of glial precursor cells and their satellite cell progeny, morphological, immunocytochemical and culture techniques were applied to the developing rat superior cervical ganglion. At embryonic day (E)18.5, numerous clusters of nonneuronal cells appeared transiently in the ganglion. Individual cells with a similar morphology were present in E16.5 ganglia, and are likely to represent the precursor cells which generate these clusters. The clustered cells were distinguishable from neighbouring neurons as well as from endothelial cells and fibroblasts. Morphologically similar cells were present in nerve bundles at E18.5 and surrounding principal neurons and nerve bundles in the adult ganglion. Double-label studies of the E18.5 ganglion with tyrosine hydroxylase to identify noradrenergic neurons and propidium iodide counterstaining to visualize all cell nuclei revealed that the cells in clusters stained with propidium iodide but lacked tyrosine hydroxylase immunoreactivity. To determine if cell clusters arose from division, bromodeoxy-uridine, a thymidine analogue, was administered to pregnant mothers between E16.5-E18.5, and ganglionic cells examined at E18.5 both in vivo and in vitro. Numerous non-neuronal cells divided during this period in situ and composed portions of clusters. When dissociated, superior cervical ganglion satellite glia reacted with an NGF-receptor antibody (MAb 217c) and possessed a flattened shape, in contrast to bipolar Schwann cells. Over half of the 217c-immunoreactive glia at E18.5 had incorporated bromodeoxyuridine during E16.5-18.5 in vivo. At birth, non-neuronal cells were no longer grouped in clusters, but were associated with neuronal cell bodies and processes. These findings suggest that, between E16.5-E18.5, glial precursors divide rapidly to form clusters, and that, after the peak of neurogenesis, daughter cells migrate within the ganglion to associate with nerve cell bodies and processes where proliferation continues at a slower rate. Distinct cellular and molecular interactions are likely to trigger the initial rapid division of glial precursors, initiate their migration and association with neuron cell bodies, and control their subsequent slower division.
在外周神经节形成早期，神经嵴细胞会产生注定分化为神经元或神经胶质细胞命运的不同前体细胞，但对于受限神经胶质前体细胞随后如何产生年轻卫星神经胶质细胞并使其成熟，我们却知之甚少。为了研究神经胶质前体细胞及其卫星细胞后代的分裂和迁移情况，我们将形态学、免疫细胞化学和培养技术应用于发育中的大鼠颈上神经节。在胚胎第（E）18.5天，神经节中短暂出现了许多非神经元细胞簇。在E16.5天的神经节中存在形态相似的单个细胞，它们很可能代表产生这些细胞簇的前体细胞。这些聚集的细胞与相邻的神经元以及内皮细胞和成纤维细胞不同。在E18.5天的神经束以及成年神经节中围绕主要神经元和神经束的区域也存在形态相似的细胞。用酪氨酸羟化酶对E18.5天的神经节进行双重标记以识别去甲肾上腺素能神经元，并用碘化丙啶复染以显示所有细胞核，结果表明，细胞簇中的细胞被碘化丙啶染色，但缺乏酪氨酸羟化酶免疫反应性。为了确定细胞簇是否由分裂产生，在E16.5 - E18.5天期间给怀孕的母鼠注射胸苷类似物溴脱氧尿苷，并在E18.5天对体内和体外的神经节细胞进行检查。在此期间，许多非神经元细胞在原位分裂并构成细胞簇的一部分。当分离时，颈上神经节卫星神经胶质细胞与NGF受体抗体（单克隆抗体217c）发生反应，并且呈扁平状，这与双极雪旺细胞不同。在E18.5天，超过一半的217c免疫反应性神经胶质细胞在E16.5 - 至18.5天的体内过程中摄取了溴脱氧尿苷。出生时，非神经元细胞不再聚集成簇，而是与神经元细胞体和突起相关联。这些发现表明，在E16.5 - E18.5天之间，神经胶质前体细胞迅速分裂形成细胞簇，并且在神经发生高峰期过后，子细胞在神经节内迁移，与神经细胞体和突起相关联，在那里增殖以较慢的速度继续进行。不同的细胞和分子相互作用可能会触发神经胶质前体细胞最初的快速分裂，启动它们的迁移以及与神经元细胞体的关联，并控制它们随后较慢的分裂。
