Romand M R, Romand R
Laboratoire de Neurobiologie, Université Blaise Pascal, Aubière, France.
J Electron Microsc Tech. 1990 Jun;15(2):144-54. doi: 10.1002/jemt.1060150206.
The development of the spiral ganglion in the cat, the rat, and the mouse was studied by electron microscopy, from fetal stages in the cat and from birth in the rodent. In the earliest stages, a single population of ganglion cells is present. Immature spiral ganglion neurons possess small perisomatic processes that seem to disappear with development, before the myelination ganglion cells are surrounded by one or two layers of Schwann cell processes. With maturation, the Schwann process increases in number around the perikaryon and its processes, which leads to the onset of myelination. The onset of myelination of the cell body processes is asynchronous. The perikaryon may be delayed in myelination by several days. Moreover, ganglion neurons from a given region of the cochlea do not myelinate simultaneously. The differentiation of two types of fibers in the intraganglionic spiral bundle and the first appearance of TII neurons occurs around birth in the cat and a few days after birth for the rat and the mouse. The distinction of TII cells is possible due to characteristic accumulation of neurofilamentous structures in the cytoplasm.
通过电子显微镜研究了猫、大鼠和小鼠螺旋神经节的发育情况，猫的研究始于胎儿期，啮齿动物的研究始于出生时。在最早阶段，存在单一的神经节细胞群体。未成熟的螺旋神经节神经元具有小的胞体周围突起，这些突起在发育过程中似乎会消失，在髓鞘形成之前，神经节细胞被一到两层施万细胞突起包围。随着成熟，施万细胞突起在核周体及其突起周围的数量增加，这导致髓鞘形成的开始。胞体突起的髓鞘形成开始是异步的。核周体的髓鞘形成可能会延迟几天。此外，来自耳蜗给定区域的神经节神经元不会同时发生髓鞘形成。神经节内螺旋束中两种纤维的分化以及II型神经元的首次出现，在猫出生时发生，在大鼠和小鼠出生后几天发生。由于细胞质中神经丝状结构的特征性积累，可以区分II型细胞。
