Hansen A, Zeiske E
Zoological Institute, University of Hamburg, Germany.
J Comp Neurol. 1993 Jul 8;333(2):289-300. doi: 10.1002/cne.903330213.
The development of the olfactory organ of the zebrafish, from the forming of early placode to the adult organ, was investigated by electron microscopy and DiI labeling. The olfactory placode is formed by a subepidermal layer of cells. These cells differ from those of the epidermis as well as from brain cells, and they do not mingle either with epidermal or with brain cells. No migration of cells from the brain or the epidermis towards the subepidermal cell layer has been observed. The cells of the subepidermal layer seem to form all cell types of the olfactory mucosa, i.e., basal cells, ciliated and microvillous receptor cells, supporting cells, and ciliated nonsensory cells. Axons grow into the forebrain at a very early stage when the epidermis still covers the placode completely. Dendrites grow out when the epidermis separates, building the olfactory pit. This process implicates neither cell lysis nor cell degeneration. The olfactory pit forms a rosette with a midline raphe and olfactory lamellae. The incurrent nostril is separated from the excurrent nostril by a funnel-shaped structure. Differentiation of the olfactory placode in the embryo is accomplished very quickly, whereas the development into the adult organ during larval stages is a slow process.
通过电子显微镜和DiI标记，研究了斑马鱼嗅觉器官从早期基板形成到成年器官的发育过程。嗅觉基板由表皮下一层细胞形成。这些细胞与表皮细胞以及脑细胞不同，它们既不与表皮细胞混合，也不与脑细胞混合。未观察到细胞从大脑或表皮向表皮下细胞层迁移。表皮下细胞层的细胞似乎形成嗅觉黏膜的所有细胞类型，即基底细胞、纤毛和微绒毛受体细胞、支持细胞和纤毛非感觉细胞。当表皮仍完全覆盖基板时，轴突在很早的阶段就长入前脑。当表皮分离形成嗅凹时，树突长出。这个过程既不涉及细胞溶解也不涉及细胞退化。嗅凹形成一个带有中线缝和嗅板的玫瑰花结。入流鼻孔通过一个漏斗形结构与出流鼻孔分开。胚胎中嗅觉基板的分化非常迅速完成，而在幼体阶段发育成成年器官是一个缓慢的过程。
