Gershon M D, Rothman T P, Joh T H, Teitelman G N
J Neurosci. 1984 Sep;4(9):2269-80. doi: 10.1523/JNEUROSCI.04-09-02269.1984.
A population of proliferating cells in the fetal gut has previously been found to express transiently aspects of a catecholaminergic phenotype (TC cells) during development in both rats and mice. These cells appear to be noradrenergic in rats but dopaminergic in mice. In the current study, the ability of TC cells, identified by the immunocytochemical demonstration of tyrosine hydroxylase (TH), to take up and become radioautographically labeled by [3H]norepinephrine ([3H]NE) was assessed. When TC cells were most numerous in the bowel of rats, no cells were labeled by [3H]NE (days E12 and E13). In rats, but not mice, labeling of larger cell bodies by [3H]NE was found on days E14 and E15. However, no cells showed TH immunoreactivity on day E15, although a few cells were doubly labeled by [3H]NE and TH immunoreactivity on day E14. Therefore, in rats TC cells contain TH immunoreactivity but do not take up [3H]NE prior to day E14, and their disappearance is followed by the appearance of a second population of larger cells that lacks TH immunoreactivity but which does take up [3H]NE. The transient appearance of some cells that express both markers on day E14 suggests, but does not prove, that TC cells change their phenotype and are the precursors of the cells found later in development that lack TH but which take up [3H]NE. The cells that take up [3H]NE are rare or absent in newborn rat gut, indicating that they may also be transient. These results indicate that genes responsible for different aspects of the noradrenergic phenotype need not necessarily be coupled in their expression. Although uptake of [3H] NE into cell bodies was not found on day E13 or later in vivo in mouse gut, it does occur in mouse bowel explanted prior to day E13 and grown for 10 to 12 days in culture. These cultures also contained TH immunoreactive cells. Thus, the potential for development of cells able to take up [3H]NE exists in mice as well as in rats, and the conditions that lead to a loss of catecholaminergic traits in vivo do not exist in vitro.
先前已发现，在大鼠和小鼠发育过程中，胎儿肠道内的一群增殖细胞会短暂表达儿茶酚胺能表型的某些方面（TC细胞）。这些细胞在大鼠中似乎是去甲肾上腺素能的，而在小鼠中是多巴胺能的。在本研究中，通过酪氨酸羟化酶（TH）的免疫细胞化学证明鉴定出的TC细胞摄取[3H]去甲肾上腺素（[3H]NE）并被放射自显影标记的能力进行了评估。当大鼠肠道中的TC细胞数量最多时，没有细胞被[3H]NE标记（胚胎第12天和第13天）。在大鼠而非小鼠中，在胚胎第14天和第15天发现较大的细胞体被[3H]NE标记。然而，在胚胎第15天没有细胞显示TH免疫反应性，尽管在胚胎第14天有一些细胞被[3H]NE和TH免疫反应性双重标记。因此，在大鼠中，TC细胞在胚胎第14天之前含有TH免疫反应性，但不摄取[3H]NE，它们消失后会出现第二批较大的细胞，这些细胞缺乏TH免疫反应性，但能摄取[3H]NE。胚胎第14天同时表达两种标记的一些细胞的短暂出现表明，但不能证明，TC细胞会改变其表型，并且是发育后期发现的缺乏TH但能摄取[3H]NE的细胞的前体。摄取[3H]NE的细胞在新生大鼠肠道中很少见或不存在，这表明它们也可能是短暂的。这些结果表明，负责去甲肾上腺素能表型不同方面的基因在表达上不一定是相关联的。虽然在胚胎第13天或之后在小鼠肠道体内未发现[3H]NE摄取到细胞体中，但在胚胎第13天之前取出并在培养中生长10至12天的小鼠肠道中确实会发生这种情况。这些培养物中也含有TH免疫反应性细胞。因此，小鼠和大鼠都存在发育出能够摄取[3H]NE的细胞的潜力，并且体内导致儿茶酚胺能特性丧失的条件在体外不存在。
