Brückner G, Brauer K, Härtig W, Wolff J R, Rickmann M J, Derouiche A, Delpech B, Girard N, Oertel W H, Reichenbach A
Paul Flechsig Institute for Brain Research, University of Leipzig, Germany.
Glia. 1993 Jul;8(3):183-200. doi: 10.1002/glia.440080306.
The nature and function of previously described perineuronal nets are still obscure. In the present study their polyanionic components were demonstrated in the rat brain using colloidal iron hydroxide (CIH) staining. In subcortical regions, such as the red nucleus, cerebellar, and vestibular nuclei, most neurons were ensheathed by CIH-binding material. In the cerebral cortex perineuronal nets were seen around numerous nonpyramidal neurons. Biotinylated hyaluronectin revealed that hyaluronan occurs in perineuronal nets. Two plant lectins [Wisteria floribunda agglutinin (WFA) and Vicia villosa agglutinin (VVA)] with affinity for N-acetylgalactosamine visualized perineuronal nets similar to those rich in anionic components. Glutamic acid decarboxylase (GAD)-immunoreactive synaptic boutons were shown to occupy numerous meshes of perineuronal VVA-positive nets. Electron microscopically, VVA binding sites were scattered throughout perisynaptic profiles, but accumulated at membranes and in the extracellular space except not in synaptic clefts. To investigate the spatial relationship between glial cell processes and perineuronal nets, two astrocytic markers (S100-protein and glutamine synthetase) were visualized at the light and electron microscopic level. Two methods to detect microglia by the use of Griffonia simplicifolia agglutinin (GSA I-B4) and the monoclonal antibody, OX-42, were also applied. Labelled structures forming perineuronal nets were observed with both astrocytic, but not with microglial, markers. It is concluded that perineuronal nets are composed of a specialized type of glia-associated extracellular matrix rich in polyanionic groups and N-acetylgalactosamine. The net-like appearance is due to perisynaptic arrangement of the astrocytic processes and these extracellular components. Similar to the ensheathment of nodes of Ranvier, perineuronal nets may provide a special ion buffering capacity required around various, perhaps highly active, types of neurons.
先前描述的神经周网的性质和功能仍不清楚。在本研究中，使用氢氧化铁胶体（CIH）染色在大鼠脑中证实了它们的聚阴离子成分。在皮质下区域，如红核、小脑和前庭核，大多数神经元被CIH结合物质包裹。在大脑皮质中，在许多非锥体神经元周围可见神经周网。生物素化的透明质酸结合蛋白显示透明质酸存在于神经周网中。两种对N-乙酰半乳糖胺有亲和力的植物凝集素[紫藤凝集素（WFA）和蚕豆凝集素（VVA）]使神经周网可视化，其类似于富含阴离子成分的神经周网。谷氨酸脱羧酶（GAD）免疫反应性突触小体被证明占据了神经周VVA阳性网的许多网孔。电子显微镜下，VVA结合位点散布在整个突触周轮廓中，但聚集在膜和细胞外空间，突触间隙除外。为了研究胶质细胞突起与神经周网之间的空间关系，在光镜和电镜水平观察了两种星形胶质细胞标记物（S100蛋白和谷氨酰胺合成酶）。还应用了两种利用简单豆科凝集素（GSA I-B4）和单克隆抗体OX-42检测小胶质细胞的方法。用星形胶质细胞标记物观察到形成神经周网的标记结构，但未用小胶质细胞标记物观察到。得出的结论是，神经周网由一种富含聚阴离子基团和N-乙酰半乳糖胺的特殊类型的胶质细胞相关细胞外基质组成。网状外观是由于星形胶质细胞突起和这些细胞外成分的突触周排列。类似于郎飞结的包裹，神经周网可能提供各种可能高度活跃的神经元周围所需的特殊离子缓冲能力。
