Srivastava U C, Pathak S V
Department of Zoology, University of Allahabad, Allahabad, U. P., India.
Cell Mol Biol (Noisy-le-grand). 2010 Oct 30;56 Suppl:OL1410-26.
To study interlaminar phenotypic variations in the pyramidal neurons of parietal isocortex in bat (Cynopterus sphinx), Golgi and Nissl methods have been employed. The parietal isocortex is relatively thin in the bat as compared to prototheria with layer III, V and VI accounting for more than two—thirds of total cortical thickness. Thick cell free layer I and thinnest accentuated layer II are quite in connotation with other chiropterids. Poor demarcation of layer III/IV in the present study is also in connotation with primitive eutherian mammal (i.e. prototherian) and other chiropterids. Most of the pyramidal cells in the different layers of the parietal isocortex are of typical type as seen in other eutherians but differ significantly in terms of soma shape and size, extent of dendritic arbor, diameter of dendrites and spine density. Percentage of pyramidal neurons, diameter of apical dendrite and spine density on apical dendrite appear to follow an increasing trend from primitive to advanced mammals; but extent of dendrites are probably governed by the specific life patterns of these mammals. It is thus concluded that 'typical' pyramidal neurons in parietal isocortex are similar in therians but different from those in prototherians. It is possible that these cells might have arisen among early eutherians after divergence from prototherian stock.
为了研究蝙蝠（犬蝠）顶叶同型皮质锥体细胞的层间表型变异，采用了高尔基染色法和尼氏染色法。与原兽亚纲动物相比，蝙蝠的顶叶同型皮质相对较薄，其中Ⅲ、Ⅴ和Ⅵ层占皮质总厚度的三分之二以上。厚的无细胞Ⅰ层和最薄的明显的Ⅱ层与其他翼手目动物相当一致。本研究中Ⅲ/Ⅳ层分界不明显也与原始真兽类哺乳动物（即原兽亚纲动物）和其他翼手目动物一致。顶叶同型皮质不同层中的大多数锥体细胞是其他真兽类动物中所见的典型类型，但在胞体形状和大小、树突分支范围、树突直径和棘密度方面有显著差异。锥体细胞的百分比、顶树突直径和顶树突上的棘密度似乎从原始哺乳动物到高等哺乳动物呈增加趋势；但树突的范围可能受这些哺乳动物特定生活模式的支配。因此得出结论，顶叶同型皮质中的“典型”锥体细胞在兽亚纲动物中相似，但与原兽亚纲动物中的不同。这些细胞可能是在与原兽亚纲动物分化后的早期真兽类动物中出现的。
