Leclerc N, Beesley P W, Brown I, Colonnier M, Gurd J W, Paladino T, Hawkes R
Department of Biochemistry, Faculty of Medicine, Laval University, Québec, Canada.
J Comp Neurol. 1989 Feb 8;280(2):197-212. doi: 10.1002/cne.902800204.
In order to study the mechanisms of synaptogenesis in the rat cerebellar cortex, a library of monoclonal antibodies has been generated against proteins of the isolated synapse. One recognizes a glycosylated 38 kDa protein that is concentrated in the synaptic vesicle fraction and resembles synaptophysin biochemically in its molecular weight, charge, and pattern of glycosylation. In the adult cerebellar cortex, the antisynaptophysin(mabQ155) immunoreactivity is codistributed with synapses. Immunoreactivity is strongest in the molecular layer where punctate deposits of reaction product outline the Purkinje cell dendrites. Discrete small profiles, consistent with the distribution of basket cell axon terminals, surround the Purkinje cells, and in the granular layer the synaptic glomeruli are intensely stained. There is no immunoreactivity in the white matter axon tracts. Electron microscope immunocytochemistry confirms the synaptic location of the antigen and suggests that the reaction product is associated with synaptic vesicles. Both round and flat vesicle populations are immunoreactive. Antisynaptophysin(mabQ155) has been used to follow synaptogenesis in the developing rat cerebellum. In the newborn rat (P0), despite the paucity of synapses, there is some specific immunoreactivity, especially in the subcortical white matter. Electron microscopy shows that the antigenicity is associated with vesicles within growth cones, filopodia, and immature axon profiles. During development, antisynaptophysin immunoreactivity increases progressively, along with the maturing cell populations, for both the granule cell-Purkinje cell and the mossy fiber-granule cell synapses. Quantitative biochemical analysis confirms the cytochemical results. These data suggest that neuronal growth cones express a synapse-specific antigen before complete morphological synapses are present.
为了研究大鼠小脑皮质中突触形成的机制，已针对分离突触的蛋白质产生了一个单克隆抗体文库。其中一种抗体识别一种糖基化的38 kDa蛋白质，该蛋白质集中在突触小泡部分，在分子量、电荷和糖基化模式上与突触素在生化性质上相似。在成年小脑皮质中，抗突触素（单克隆抗体Q155）免疫反应性与突触共分布。免疫反应性在分子层最强，反应产物的点状沉积勾勒出浦肯野细胞树突。离散的小轮廓与篮状细胞轴突终末的分布一致，围绕着浦肯野细胞，在颗粒层中突触小球被强烈染色。白质轴突束中没有免疫反应性。电子显微镜免疫细胞化学证实了抗原的突触定位，并表明反应产物与突触小泡相关。圆形和扁平小泡群体均具有免疫反应性。抗突触素（单克隆抗体Q155）已被用于追踪发育中小鼠小脑的突触形成。在新生大鼠（出生后0天），尽管突触稀少，但仍有一些特异性免疫反应性，尤其是在皮质下白质中。电子显微镜显示，抗原性与生长锥、丝状伪足和未成熟轴突轮廓内的小泡相关。在发育过程中，对于颗粒细胞 - 浦肯野细胞突触和苔藓纤维 - 颗粒细胞突触，抗突触素免疫反应性随着细胞群体的成熟而逐渐增加。定量生化分析证实了细胞化学结果。这些数据表明，在完整的形态学突触出现之前，神经元生长锥表达一种突触特异性抗原。
