新生猫视皮质胼胝体神经元的DiI示踪研究

DiI LABELING OF CALLOSAL NEURONS IN THE VISUAL CORTEX OF NEONATAL CAT

采用ＤｉＩ示踪法研究了新生猫视皮质的胼胝体神经元的分布和形态．ＤｉＩ标记的胼胝体神经元普遍分布于视皮质各区，包括在成年时缺乏胼胝体联系的１７区内侧部．这些标记的神经元位于除Ⅰ层外的皮质各层中，但大部分位于Ⅲ展并有成簇分布的倾向．ＤｉＩ标记的胼胝体神经元，特别是位于Ⅱ／Ⅲ层者大多呈“Ｇｏｌｇｉ样”标记，其树突走行和各级分支，甚至树突棘均清晰易辨．上述结果除证实以往用其他方法证明的新生猫视皮质胼胝体神经元的分布外，还显示了标记神经元的详细形态特点，表明ＤｉＩ示踪法是研究发育中的神经通路起源细胞及其突起形态的一种简单而有效的手段．

The distribution and morphology of callosal neurons in the visual cortex of neonatal cat was studied with retrograde labeling method of the carbocyanine dye DiI. DifI labeled calledal neutons were distributed continuously throughout the visual cortex including medial area 17 in which callosal connections were lacking in the adult. Labeled callosal neurons were found in all conical layers except layer Ⅰ and most of them were located in layer Ⅲ. In layers,Ⅱ/Ⅲ, the labeled callosal neurons tended to distribute in clusters and often showed 'Golgi-like' labeling. The trajectoties, branches, even spines of the labefed dendrites were clearly identified. In addition to confirming the distribution pattern of callosal neurons revealed previously by retrograde tracers. the present study demonstrated the detailed morphology of the labeled callosal neurons in the visual cortex of neonatal cat.This indicates that DiI is a simple and effective tool to investigate the connections as well as the morphological details of the cell origins and their dendrites of certain neuronal pathways during development.