Immunoelectron microscopic localization of the neural recognition molecules L1, NCAM, and its isoform NCAM180, the NCAM-associated polysialic acid, Beta1 integrin and the extracellular matrix molecule tenascin-R in synapses of the adult rat hippocampus
Immunoelectron microscopic localization of the neural recognition molecules L1, NCAM, and its isoform NCAM180, the NCAM-associated polysialic acid, Beta1 integrin and the extracellular matrix molecule tenascin-R in synapses of the adult rat hippocampus
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DOI：
10.1002/neu.1071
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发表时间：
2001-11-05
期刊：
影响因子：
--
通讯作者：
Schachner，M
中科院分区：
文献类型：
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作者：
Schuster，T;Krug，M;Schachner，M
我们研究了不同形态的成年啮齿动物海马三环兴奋性谷氨酸能突触显示不同类型的长时程增强(LTP)的可能性，它们可能以不同的方式表达免疫球蛋白超家族识别分子L1和NCAM、细胞外基质分子tenascin-R和细胞外基质受体成分Beta1整合素。神经细胞黏附分子L1、NCAM(三种主要异构体)、NCAM180(胞浆结构域最长的最大主要异构体)、β1整合素、与NCAM相关的聚唾液酸(PSA)和Tenascin-R通过包埋前免疫组织化学方法定位于成年大鼠海马区CA3/CA4区(苔藓纤维突触)和齿状回(脊突突触)。在突触前表达LTP的苔藓纤维突触的突触膜没有显示出可检测到的对所研究的任何分子/表位的免疫反应水平。L1、NCAM和PSA可在束状苔藓纤维轴索膜上检测到，但未检测到NCAM180或β1整合素。与苔藓纤维突触不同的是，齿状回分子层外1/3处的脊突触对NCAM、NCAM180、β1整合素和PSA均呈免疫阳性和免疫阴性反应，显示LTP的突触后表达机制。突触后NCAM或PSA免疫反应阳性的脊突触在其突触前膜上也有免疫反应。突触前未检测到NCAM180。L1在突触前和突触后均未发现。此外，在所有被测试的突触的突触间隙中都没有检测到细胞外基质分子tenascin-R，但在束状轴突、轴突-星形细胞接触区和星形细胞缝隙连接之间大量存在。两种类型突触膜结合黏附分子表达的差异可能反映了诱导和/或维持突触可塑性的不同机制。©2001 John Wiley&Sons，Inc.神经生物学杂志49：142-158,2001
We have investigated the possibility that morphologically different excitatory glutamatergic synapses of the “trisynaptic circuit” in the adult rodent hippocampus, which display different types of long‐term potentiation (LTP), may express the immunoglobulin superfamily recognition molecules L1 and NCAM, the extracellular matrix molecule tenascin‐R, and the extracellular matrix receptor constituent beta1 integrin in a differential manner. The neural cell adhesion molecules L1, NCAM (all three major isoforms), NCAM180 (the largest major isoform with the longest cytoplasmic domain), beta1 integrin, polysialic acid (PSA) associated with NCAM, and tenascin‐R were localized by pre‐embedding immunostaining procedures in the CA3/CA4 region (mossy fiber synapses) and in the dentate gyrus (spine synapses) of the adult rat hippocampus. Synaptic membranes of mossy fiber synapses where LTP is expressed presynaptically did not show detectable levels of immunoreactivity for any of the molecules/epitopes studied. L1, NCAM, and PSA, but not NCAM180 or beta1 integrin, were detectable on axonal membranes of fasciculating mossy fibers. In contrast to mossy fiber synapses, spine synapses in the outer third of the molecular layer of the dentate gyrus, which display postsynaptic expression mechanisms of LTP, were both immunopositive and immunonegative for NCAM, NCAM180, beta1 integrin, and PSA. Those spine synapses postsynaptically immunoreactive for NCAM or PSA also showed immunoreactivity on their presynaptic membranes. NCAM180 was not detectable presynaptically in spine synapses. L1 could not be found in spine synapses either pre‐ or postsynaptically. Also, the extracellular matrix molecule tenascin‐R was not detectable in synaptic clefts of all synapses tested, but was amply present between fasciculating axons, axon‐astrocyte contact areas, and astrocytic gap junctions. Differences in expression of the membrane‐bound adhesion molecules at both types of synapses may reflect the different mechanisms for induction and/or maintenance of synaptic plasticity. © 2001 John Wiley & Sons, Inc. J Neurobiol 49: 142–158, 2001