Blümcke I, Eggli P, Celio M R
Department of Histology and General Embryology, University of Fribourg, Switzerland.
Glia. 1995 Oct;15(2):131-40. doi: 10.1002/glia.440150205.
"Perineuronal nets" (PNs) ensheath a subtype of inhibitory neurons in the mammalian neocortex. In the light of the proposal that PNs consist of glial processes, we have analyzed the relationship between intracellularly injected glial cells and PNs in the rat neocortex. Glial cells were injected iontophoretically with Lucifer Yellow in lightly fixed tissue slices and PNs were visualized with the lectin from Vicia villosa. Using confocal laser scanning microscopy, glial processes and PNs were identified as distinct structures. Lectin labeling was consistently associated with the extracellular space interposed between LY-labeling was consistently associated with the extracellular space interposed between LY-labeled astrocyte processes and neurons. Of the different types of glial cells injected, only the densely-ramifying protoplasmic astrocytes extended processes which could be traced to contact PNs. These protoplasmic astrocytes also sent out processes to adjacent neurons not ensheathed by PNs, and to capillaries. The present data strongly suggests that PNs do not consist of glial processes but rather support the idea that PNs represent specialized extracellular material interposed between the surface of some inhibitory interneurons and astrocytic processes.
“神经元周围网”（PNs）包裹着哺乳动物新皮层中的一类抑制性神经元。鉴于有观点认为PNs由神经胶质细胞突起构成，我们分析了大鼠新皮层中经细胞内注射的神经胶质细胞与PNs之间的关系。在轻度固定的组织切片中，用离子电渗法将荧光黄注入神经胶质细胞，并用来自野豌豆的凝集素使PNs可视化。使用共聚焦激光扫描显微镜，神经胶质细胞突起和PNs被识别为不同的结构。凝集素标记始终与位于LY标记的星形胶质细胞突起和神经元之间的细胞外间隙相关。在注射的不同类型神经胶质细胞中，只有高度分支的原浆性星形胶质细胞伸出的突起可追踪到与PNs接触。这些原浆性星形胶质细胞还向未被PNs包裹的相邻神经元以及毛细血管发出突起。目前的数据强烈表明PNs并非由神经胶质细胞突起构成，而是支持了PNs代表介于某些抑制性中间神经元表面和星形胶质细胞突起之间的特殊细胞外物质这一观点。
