Csillik B, Nemcsók J, Boncz I, Knyihár-Csillik E
Department of Anatomy, Albert Szent-Györgyi University Medical School, Szeged, Hungary.
Neurobiology (Bp). 1998;6(4):383-404.
Nitric oxide synthase (NOS) and the nicotinic acetylcholine receptor (nAChR) immunoreactivity of the cerebral cortex was studied in adult Macaca fascicularis monkeys at light- and electron microscopic levels. NOS was located by means of the polyclonal antibodies developed by Transduction Laboratories (Lexington, KY, USA), as primary serum, in a dilution of 1:1000, and nAChR was located by means of biotinylated alpha-bungarotoxin (BTX) obtained from Molecular probes (Eugene, Oregon, USA) in a dilution of 1:2000. While endothelial eNOS outlined blood vessels in the brain, brain-derived (neural) bNOS labelled three well-defined cell types in area 46 of the prefrontal cortex, viz. (a) bipolar cells, scattered through layers III to V, equipped with long dendrites which pass over the thickness of the cortex in a right angle to the pial surface, establishing dendritic bundles closely reminiscent of a columnar organization; (b) large multipolar cells, located mainly in layers V and VI, with axons which interconnect dendritic bundles of the bipolar cells and establish synapses with dendritic shafts and spines of the former; and (c) stellate cells, located in lamina II and III, which establish an axonal network in lamina zonalis (lamina I). This arrangement is most characteristic in area 46 of the prefrontal cortex; areas 10 and 12 display similar features. In contrast, the primary visual cortex (area 17), is lacking any sign of columnar organization. Localization of bNOS immunoreactivity is at marked variance to that of NADPH-diaphorase which labels large pyramidal cells in the primate cortex. Binding of alpha-bungarotoxin (BTX) which labels the alpha 7 subunit of nAChR is located in somata, dendrites and axons of interneurons scattered over the entire width of the prefrontal cortex; on the other hand, the monoclonal antibody mAb 35 which labels subunits alpha 1, alpha 3 and alpha 5 in the main immunogenic region of the receptor, visualizes apical dendritic shafts similar to those like bNOS. Strategic localization of bNOS in the primate prefrontal cortex fulfills criteria of producing a freely diffusing retrograde messenger molecule operative in signal transduction routes subserving topography and columnar organization of the cortex, as well as long-term potentiation and long-term depression phenomena underlying mnemonic and gnostic functions. Common occurrence of bNOS and nAChR in identical or similar structures in the prefrontal cortex suggests that interactions between nitrogen oxide and presynaptically released acetylcholine might be involved in the metasynaptic organization of the cerebral cortex, operating in a non-synaptic manner in maintaining optimal performance on cognitive tasks.
在成年食蟹猴的大脑皮层中，利用光镜和电镜技术研究了一氧化氮合酶（NOS）和烟碱型乙酰胆碱受体（nAChR）的免疫反应性。NOS通过美国肯塔基州列克星敦Transduction Laboratories公司研制的多克隆抗体作为一抗血清进行定位，稀释度为1:1000；nAChR通过美国俄勒冈州尤金Molecular probes公司提供的生物素化α-银环蛇毒素（BTX）进行定位，稀释度为1:2000。脑内皮细胞型一氧化氮合酶（eNOS）勾勒出脑内血管，而脑源性（神经型）一氧化氮合酶（bNOS）标记前额叶皮层46区的三种明确细胞类型，即：（a）双极细胞，散布于III至V层，具有长树突，与软膜表面呈直角穿过皮层厚度，形成与柱状组织极为相似的树突束；（b）大多极细胞，主要位于V层和VI层，其轴突连接双极细胞的树突束，并与前者的树突干和棘形成突触；（c）星状细胞，位于II层和III层，在带状层（I层）形成轴突网络。这种排列在前额叶皮层46区最为典型；10区和12区也有类似特征。相比之下，初级视皮层（17区）没有任何柱状组织的迹象。bNOS免疫反应性的定位与标记灵长类皮层大锥体细胞的NADPH-黄递酶的定位明显不同。标记nAChRα7亚基的α-银环蛇毒素（BTX）结合位于散布在前额叶皮层整个宽度的中间神经元的胞体、树突和轴突中；另一方面，标记受体主要免疫原区α1、α3和α5亚基的单克隆抗体mAb 35使类似于bNOS的顶树突干可视化。bNOS在灵长类前额叶皮层的特定定位符合产生一种可自由扩散的逆行信使分子的标准，该分子在信号转导途径中起作用，可以维持皮层的地形和柱状组织，以及记忆和认知功能所依赖的长时程增强和长时程抑制现象。前额叶皮层相同或相似结构中bNOS和nAChR的共同存在表明，一氧化氮与突触前释放的乙酰胆碱之间的相互作用可能参与了大脑皮层的突触后组织，以非突触方式维持认知任务的最佳表现。
