Different polysialic acid-neural cell adhesion molecule expression patterns in distinct types of mossy fiber boutons in the adult hippocampus
Different polysialic acid-neural cell adhesion molecule expression patterns in distinct types of mossy fiber boutons in the adult hippocampus
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DOI：
10.1002/(sici)1096-9861(19990719)410:1
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发表时间：
1999-07-19
影响因子：
2.5
通讯作者：
Arai, Y
中科院分区：
文献类型：
--
作者：
Seki, T;Arai, Y
齿状颗粒细胞在成年海马中继续生成，并且新生成的颗粒细胞表达高度聚唾液酸化的神经细胞粘附分子（PSA-NCAM），其已被证明在神经发育和可塑性中是重要的。在本研究中，PSA-NCAM的表达模式在形态学上不同类型的苔藓纤维结在成年大鼠进行了研究，免疫电子显微镜和共聚焦激光扫描显微镜。虽然苔藓纤维束内的许多无髓轴突表达PSA-NCAM，但大多数成熟类型的苔藓纤维终扣对聚唾液酸（PSA）呈阴性，但对NCAM肽呈阳性，表明NCAM在成熟苔藓纤维终扣中的聚唾液酸化程度较低。另一方面，PSA表现为小圆形静脉曲张、不规则形状的终扣和假定的未成熟类型的苔藓纤维终扣。PSA阳性小终扣与CA 3区锥体细胞和非锥体细胞形成突触联系。PSA表达的推定未成熟的终扣含有较少的明确的突触囊泡和线粒体，在某些情况下，他们陷入的PSA阳性，指状树突状衍生物所产生的树突状轴的锥体细胞，这是已知的发展成苔藓纤维终扣多刺赘生物复合物。这些结果表明，不同类型的苔藓纤维终扣在成年海马具有不同的PSA表达模式，他们也意味着PSA的表达允许苔藓纤维有能力调节终扣的形成和重塑，伴随着突触形成的接触网站与锥体细胞和非锥体细胞。(C)1999 Wiley-Liss，Inc.
Dentate granule cells continue to be generated in the adult hippocampus, and the newly generated granule cells express the highly polysialylated neural cell adhesion molecule (PSA-NCAM), which has been shown to be important in neural development and plasticity. In the present study, the PSA-NCAM expression pattern in morphologically distinct types of mossy fiber boutons in adult rats was examined by immunoelectron and confocal laser scanning microscopy. Although many unmyelinated axons within the mossy fiber bundles expressed PSA-NCAM, most of the mature type of mossy fiber boutons were negative for polysialic acid (PSA) but positive for NCAM peptides, suggesting that NCAM is less polysialylated in the mature mossy fiber boutons. On the other hand, PSA was expressed by small round varicosities, irregularly shaped boutons, and the presumptive immature type of mossy fiber boutons. The PSA-positive small boutons were found to make synaptic contacts with CA3 pyramidal cells and nonpyramidal cells. The PSA-expressing presumptive immature boutons contained fewer clear synaptic vesicles and mitochondria, and, in some instances, they were invaginated by the PSA-positive, finger-like dendritic outgrowths arising from the dendritic shafts of the pyramidal cells, which are known to develop into a mossy fiber bouton-thorny excrescence complex. These findings indicate that distinct types of the mossy fiber boutons possess different PSA expression patterns in the adult hippocampus, and they also imply that PSA expression allows the mossy fibers to have the ability to regulate the bouton formation and remodeling that accompany synapse formation at the contact sites with pyramidal cells and nonpyramidal cells. (C) 1999 Wiley-Liss, Inc.