Baetge G, Gershon M D
Department of Anatomy and Cell Biology, College of Physicians and Surgeons, Columbia University, New York, New York 10032.
Dev Biol. 1989 Mar;132(1):189-211. doi: 10.1016/0012-1606(89)90217-0.
Catecholaminergic cells are transiently present during development of the fetal murine bowel. These transient catecholaminergic (TC) cells appear at Day E10, but by Day E13 can no longer be detected. In order to evaluate the hypothesis that these cells are the precursors of enteric neurons, we investigated the possibilities that TC cells coexpress neuronal and catecholaminergic markers, that they can be found along the presumed path followed by crest-derived cells migrating to the gut, and that they are proliferating. TC cells were identified immunocytochemically using polyclonal or monoclonal antibodies to tyrosine hydroxylase (TH). At Day E9.5, TH-immunoreactive cells were observed to be present along the wall of the primordial esophagus in lines that extended from the developing nodose ganglia down to the boundary of the stomach. At Day E9.5, TC cells were absent from the remaining foregut. These lines of esophageal TH-immunoreactive cells became continuous with similar cells in the wall of the stomach and duodenum on Day E10. Coincident expression of neurofilament immunoreactivity was seen in all of the esophageal TH-immunoreactive cells present at Day E9.5, as well as in the entire set of esophageal and lower enteric TH-immunoreactive cells present at Day E10 (or later); moreover, at Days E9.5 and E10, all of the neurofilament-immunoreactive cells in the esophagus, stomach, or duodenum were also TH-immunoreactive. In contrast, neurofilament immunoreactivity was not expressed by the endodermally derived pancreatic duct and islet cells, which were also TH-immunoreactive; nor could expression of neurofilament immunoreactivity be detected in the TH-immunoreactive cells of the nodose ganglia. It was not until Day E11 that neurofilament-immunoreactive cells, which did not coexpress TH immunoreactivity (the definitive phenotype of enteric neurons) began to appear in the gut. Vagal axons reached as far distally as the nodose ganglion on Day E9.5, the esophagogastric junction on Day E10, and did not enter the stomach until Day E11. When the vagus nerves reached their level, the TH-immunoreactive cells in the wall of the esophagus came to lie among the nerve fibers. TH-immunoreactive cells are thus present on the pathway ultimately followed by the vagus nerves, but they develop before vagal fibers reach their level. The vagal TH-immunoreactive cells, therefore, are probably not initially migrating on vagal fibers, but appear instead to be overtaken by the descending vagus nerves.(ABSTRACT TRUNCATED AT 400 WORDS)
儿茶酚胺能细胞在胎鼠肠道发育过程中短暂存在。这些短暂的儿茶酚胺能（TC）细胞在胚胎第10天出现，但到胚胎第13天就不再能检测到。为了评估这些细胞是肠神经元前体的假说，我们研究了以下可能性：TC细胞共表达神经元和儿茶酚胺能标志物；它们可以在嵴衍生细胞迁移到肠道所遵循的假定路径上被发现；以及它们正在增殖。使用针对酪氨酸羟化酶（TH）的多克隆或单克隆抗体通过免疫细胞化学方法鉴定TC细胞。在胚胎第9.5天，观察到TH免疫反应性细胞沿着原始食管壁呈线状分布，这些线从发育中的结状神经节向下延伸至胃的边界。在胚胎第9.5天，其余的前肠中没有TC细胞。在胚胎第10天，这些食管TH免疫反应性细胞线与胃和十二指肠壁中的类似细胞相连。在胚胎第9.5天存在的所有食管TH免疫反应性细胞以及在胚胎第10天（或之后）存在的所有食管和下部肠道TH免疫反应性细胞中都观察到神经丝免疫反应性的共表达；此外，在胚胎第9.5天和第10天，食管、胃或十二指肠中的所有神经丝免疫反应性细胞也都是TH免疫反应性的。相比之下，内胚层来源的胰管和胰岛细胞不表达神经丝免疫反应性，这些细胞也是TH免疫反应性的；在结状神经节的TH免疫反应性细胞中也检测不到神经丝免疫反应性的表达。直到胚胎第11天，不共表达TH免疫反应性（肠神经元的确定表型）的神经丝免疫反应性细胞才开始在肠道中出现。迷走神经轴突在胚胎第9.5天最远到达结状神经节，在胚胎第10天到达食管胃交界处，直到胚胎第11天才进入胃。当迷走神经到达其相应水平时，食管壁中的TH免疫反应性细胞位于神经纤维之间。因此，TH免疫反应性细胞存在于迷走神经最终所经过的路径上，但它们在迷走神经纤维到达其相应水平之前就已发育。因此，迷走神经TH免疫反应性细胞最初可能不是在迷走神经纤维上迁移，而是似乎被下行的迷走神经所赶上。（摘要截断于400字）
