Fuxe K, Tinner B, Staines W, David G, Agnati L F
Department of Neuroscience, Karolinska Institute, Solna, Sweden.
Brain Res. 1997 Jan 23;746(1-2):25-33. doi: 10.1016/s0006-8993(96)01130-4.
In the present paper immunocytochemical analysis at the fluorescence microscopical level has been performed of neural cell adhesion. molecule (NCAM) immunoreactivity in the adult rat tel- and diencephalon in order to further substantiate the highly selective neuronal localization of NCAM immunoreactivity, using an affinity purified rabbit antiserum recognizing homologous NCAM proteins from rat brain. Also, double immunolabelling experiments were performed with monoclonal antibodies specific for heparan sulfate related epitopes or gamma-aminobutyric acid (GABA) to establish in which cell populations a colocalization existed with immunoreactive heparan sulfate proteoglycans of GABA. Within the neocortex NCAM immunoreactivity was exclusively localized to the area of the cell membrane of soma and proximal dendrites of subsets of large pyramidal nerve cells of the layer 5 of the frontoparietal cortex. Within the dorsal hippocampus, the NCAM immunoreactivity was exclusively located to the cell surface area of the pyramidal cell bodies of area CA2. Two colour immunofluorescence procedures demonstrated a colocalization of NCAM and 3G10 but not 10E4 immunoreactivities in the cell surface area of many of the NCAM-positive nerve cell bodies of these two regions. Within the thalamus, strong NCAM immunoreactivity was exclusively demonstrated at all rostrocaudal levels of the reticular thalamic nucleus. The horizontal band of NCAM immunoreactivity was not continuous, but split up into patches of NCAM immunoreactivity within groups of nerve cell bodies. When analysing the number of cells per unitary square in the rostrocaudal direction, a significant increase of positive cells was found in the rostral and middle thirds versus the caudal third of the reticular thalamic nucleus. Many of the cell bodies with NCAM immunoreactivity in their cell surface are showed cytoplasmic GABA immunoreactivity. In the three regions shown to contain NCAM immunoreactivity, proteins of the NCAM type may play a special role for the maintenance of the synaptic structure. The findings also suggest that the sulfated proteoglycans and NCAM can interact in the regulation of cell-cell interaction via adhesion. In the reticular thalamic nucleus NCAM molecules may be part of a set of cell-adhesion molecules involved in a structural organization of the nucleus, which allows it to play a key role in relating cortical maps to thalamic maps.
在本论文中，为了进一步证实神经细胞黏附分子（NCAM）免疫反应性的高度选择性神经元定位，利用一种亲和纯化的兔抗血清识别大鼠脑内同源的NCAM蛋白，在荧光显微镜水平对成年大鼠端脑和间脑进行了免疫细胞化学分析。此外，还进行了双重免疫标记实验，使用针对硫酸乙酰肝素相关表位或γ-氨基丁酸（GABA）的单克隆抗体，以确定哪些细胞群体中存在与GABA免疫反应性硫酸乙酰肝素蛋白聚糖的共定位。在新皮质内，NCAM免疫反应性仅定位于额顶叶皮质第5层大锥体细胞亚群的胞体和近端树突的细胞膜区域。在背侧海马中，NCAM免疫反应性仅位于CA2区锥体细胞体的细胞表面区域。双色免疫荧光程序显示，在这两个区域许多NCAM阳性神经细胞体的细胞表面区域，NCAM和3G10免疫反应性存在共定位，但与10E4免疫反应性不存在共定位。在丘脑内，在丘脑网状核的所有前后水平均仅显示出强烈的NCAM免疫反应性。NCAM免疫反应性的水平带不连续，而是在神经细胞体群内分裂成NCAM免疫反应性斑块。当分析沿前后方向每单位面积的细胞数量时，发现丘脑网状核头侧和中间三分之一区域的阳性细胞数量比尾侧三分之一区域显著增加。许多细胞表面具有NCAM免疫反应性的细胞体显示出胞质GABA免疫反应性。在显示含有NCAM免疫反应性的三个区域中，NCAM类型的蛋白质可能在维持突触结构方面发挥特殊作用。这些发现还表明，硫酸化蛋白聚糖和NCAM可以通过黏附在细胞间相互作用的调节中相互作用。在丘脑网状核中，NCAM分子可能是参与该核结构组织的一组细胞黏附分子的一部分，这使其能够在将皮质图谱与丘脑图谱联系起来方面发挥关键作用。
