5-HT containing enteroendocrine cells (EEC), the most abundant type of EEC in the gut, regulate many functions including motility, secretion and inflammatory responses. We examined the morphologies of 5-HT cells from stomach to rectum, patterns of hormone co-expression in the stomach and colon, and the relationship of 5-HT cells with nerve fibres. We also reviewed some of the relevant literature. The morphologies of 5-HT cells were distinct, depending on their location in the gut. A noticeable feature of some 5-HT cells in the antrum and colon was their long basal processes, which resembled processes of neurons, whereas 5-HT cells in the small intestinal mucosa lacked basal processes. In the stomach, numerous 5-HT cells, including cells with basal processes, were identified as enterochromaffin-like cells by their expression of histidine decarboxylase. In the colon, we observed a small number of 5-HT cells that were in close contact with, but distinct from, oxyntomodulin (OXM) and PYY immunoreactive EEC. We did not find specific relationships between nerve fibres and the processes of colonic 5-HT cells. We conclude that five major features, i.e., gut region, morphology, hormone content, receptor repertoire and cell lineage, can be used to define 5-HT cells.

含有 5-HT 的肠内分泌细胞 (EEC) 是肠道中最丰富的 EEC 类型，可调节许多功能，包括运动、分泌和炎症反应。我们检查了从胃到直肠的 5-HT 细胞的形态、胃和结肠中激素共表达的模式以及 5-HT 细胞与神经纤维的关系。我们还回顾了一些相关文献。5-HT 细胞的形态是不同的，这取决于它们在肠道中的位置。胃窦和结肠中一些5-HT细胞的一个显着特征是它们的长基底突起，类似于神经元的突起，而小肠粘膜中的5-HT细胞缺乏基底突起。在胃中，许多 5-HT 细胞，包括具有基底突起的细胞，通过组氨酸脱羧酶的表达鉴定为肠嗜铬细胞样细胞。在结肠中，我们观察到少量 5-HT 细胞，它们与泌酸调节素 (OXM) 和 PYY 免疫反应性 EEC 密切接触，但又与之不同。我们没有发现神经纤维与结肠 5-HT 细胞过程之间的特定关系。我们得出结论，五个主要特征，即肠道区域、形态、激素含量、受体库和细胞谱系，可用于定义 5-HT 细胞。