Matsuda S, Desaki J, Aburaya J, Sakanaka M
Department of Anatomy, Ehime University School of Medicine, Shigenobu, Japan.
Anat Embryol (Berl). 1997 Feb;195(2):137-46. doi: 10.1007/s004290050032.
The perikaryal projections of sensory ganglion neurons in chick embryos were observed by scanning electron microscopy after removal of the connective tissues and satellite cells by enzymatic digestion treatment. The perikaryal projections were seen not only on the surface of the perikarya but also on the surface of the stem processes. The projections were up to 3 microm in length, and their transverse diameters ranged between 0.12 and 0.24 microm from incubation (embryonic) day 10 to posthatching day 2. On days 6 and 8 of incubation, thicker projections with transverse diameters of 0.24-0.9 microm were observed transiently in addition to those described above, and some of them looked like vestiges of neuronal processes during development. The thin projections emerging mainly in the later developmental stages increased in number as spindle-shaped bipolar neurons differentiated into (pseudo)unipolar cells. Morphometric analysis revealed that the density of perikaryal projections correlated well with the shape and size of each neuron; thin perikaryal projections were more numerous on those of mature pseudounipolar neurons than on the surface of premature ganglion neurons, and they increased in number as the individual ganglion cell bodies grew larger. The neuronal shape- and size-dependent increase in perikaryal projections during development may support the hypothesis that perikaryal projections are structural devices for increasing neuronal surface areas and possibly the efficiency of metabolic activities.
通过酶消化处理去除结缔组织和卫星细胞后，利用扫描电子显微镜观察了鸡胚感觉神经节神经元的胞体投射。胞体投射不仅见于胞体表面，也见于树突干表面。这些投射长度可达3微米，从孵化（胚胎）第10天到孵化后第2天，其横向直径在0.12至0.24微米之间。在孵化第6天和第8天，除上述投射外，还短暂观察到横向直径为0.24 - 0.9微米的较粗投射，其中一些看起来像是发育过程中神经元突起的遗迹。主要在发育后期出现的细投射随着纺锤形双极神经元分化为（假）单极细胞而数量增加。形态计量学分析表明，胞体投射的密度与每个神经元的形状和大小密切相关；成熟假单极神经元表面的细胞体投射比未成熟神经节神经元表面的更多，并且随着单个神经节细胞体变大，其数量增加。发育过程中神经元形状和大小依赖性的胞体投射增加可能支持这样的假设，即胞体投射是增加神经元表面积以及可能提高代谢活动效率的结构装置。
