Colombo J A, Härtig W, Lipina S, Bons N
Programa Unidad de Neurobiología Aplicada, (CEMIC-CONICET), Buenos Aires, Argentina.
Anat Embryol (Berl). 1998 May;197(5):369-76. doi: 10.1007/s004290050147.
Previous observations have shown that astrocytes with interlaminar processes are present in the cerebral cortex of humans and New and Old World monkeys, but not in the rodent. The present report furthers the analysis of possible evolutionary aspects regarding the expression of such astroglial features. A comparison between young and adult Microcebus murinus, a prosimian, and Old World monkeys (Macaca mulatta and Papio hamadryas) is presented. Brain samples were processed for glial fibrillary acidic protein (GFAP), vimentin, MAP2 and SMI 311 immunocytochemistry, using different procedures. The cerebral cortex of adult Microcebus showed the presence of long astroglial processes, albeit reduced in number and length with respect to those observed in Old World monkeys. Macaca and Papio showed dense packing of such processes extending in most cortical regions to a depth of approximately 700 micrometers. Based on double immunolabelling for GFAP and MAP 2 antigens, the location and extent of these processes was shown to overlap with areas traversed by bundles and individual apical dendrites. Aged Old World specimens depicted an increased thickness of terminal portions of interlaminar processes, with increased morphological alterations. Comparisons made between the average thickness of the "brush" composed of interlaminar processes and the thickness of lamina I among the species analyzed disclosed an absence of relationship between them. This suggests that interlaminar processes do not represent cellular adaptations to the increase in thickness in superficial cortical laminae, but rather to some other evolutionary pressure. Since astroglial interlaminar processes are already present in a prosimian, although in a comparatively reduced manner, it is suggested that such processes underwent an early expression within the primate order, with increasing presence in more recent primate species.
先前的观察表明，具有层间突的星形胶质细胞存在于人类以及新旧世界猴的大脑皮层中，但在啮齿动物中不存在。本报告进一步分析了此类星形胶质细胞特征表达可能的进化方面。本文对一种原猴——年幼和成年的倭狐猴与旧世界猴（猕猴和阿拉伯狒狒）进行了比较。使用不同方法对脑样本进行胶质纤维酸性蛋白（GFAP）、波形蛋白、微管相关蛋白2（MAP2）和SMI 311免疫细胞化学处理。成年倭狐猴的大脑皮层显示存在长的星形胶质细胞突，尽管其数量和长度相对于旧世界猴中观察到的有所减少。猕猴和狒狒显示出此类突起密集排列，在大多数皮质区域延伸至约700微米的深度。基于GFAP和MAP2抗原的双重免疫标记，这些突起的位置和范围显示与束状结构和单个顶端树突所穿过的区域重叠。年老的旧世界猴标本显示层间突末端部分厚度增加，形态改变增多。在所分析的物种中，对由层间突组成的“刷”的平均厚度与I层厚度进行比较，结果显示它们之间不存在关联。这表明层间突并非细胞对表层皮质层厚度增加的适应性变化，而是对其他某种进化压力的适应。由于星形胶质细胞层间突在原猴中就已存在，尽管相对较少，因此表明此类突起在灵长目动物中早期就已表达，且在更近的灵长类物种中出现得越来越多。
