Developmental study of dendritic bundles in layer 1 of the rat granular retrosplenial cortex with special reference to a cell adhesion molecule, OCAM
Developmental study of dendritic bundles in layer 1 of the rat granular retrosplenial cortex with special reference to a cell adhesion molecule, OCAM
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DOI：
10.1046/j.1460-9568.2003.02900.x
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发表时间：
2003-10-01
影响因子：
3.4
通讯作者：
Rockland, KS
中科院分区：
文献类型：
--
作者：
Ichinohe, N;Yoshihara, Y;Rockland, KS
在成年大鼠的颗粒脾后皮质(GRS)中，在第2层向外投射的锥体神经元在第1层形成30-100微米宽的树突束。这些树突束的独特之处使GRS成为研究与树突模块化有关的发育、微回路和基本组织特征的一个有吸引力的模型系统。在这篇报道中，我们研究了树突束的发育过程，用免疫组织化学方法显示了微管相关蛋白2(MAP2)和谷氨酸受体2/3亚单位(GluR2/3)。第1层中的束在出生后第5天就很明显，首先是GluR2/3，然后是出生后第14天的Map2。作为了解树突状细胞聚集机制的一步，我们进一步研究了细胞黏附分子OCAM表达的个体发育。从出生后3天到成年，OCAM在第1层呈斑块状分布，OCAM免疫反应性较弱的区域选择性地与树突束(GluR2/3和MAP2)相对应。OCAM免疫反应区的周期性几何形状、出现的时间进程以及与束互补的明显定位支持了该分子可能是树突模块的建立和维持的贡献者之一。OCAM高反应区与第1层树突束之间的交错关系提示，OCAM可能对这些树突束的形成具有排斥作用。
In the granular retrosplenial cortex (GRS) of adult rats, callosally projecting pyramidal neurons in layer 2 form dendritic bundles, 30-100 mum wide, in layer 1. The distinctness of these bundles makes the GRS an attractive model system for investigating the developmental, microcircuitry, and basic organizational features related to dendritic modularity. In this report, we investigate the developmental time course of the dendritic bundles, visualized by immunohistochemistry for microtubule-associated protein 2 (MAP2) and glutamate receptor subunits 2/3 (GluR2/3). Bundles in layer 1 are apparent as early as postnatal day 5, first with GluR2/3 and then, from postnatal day 14, with MAP2. As a step toward understanding the mechanisms of dendritic aggregation, we further investigated the ontogeny of expression of the cell adhesion molecule OCAM. OCAM exhibits a patchy distribution in layer 1 from postnatal day 3 to adult, and the regions of weak OCAM immunoreactivity selectively correspond to the dendritic bundles (in both GluR2/3 and MAP2). The periodic geometry of OCAM-immunoreactive regions, the time course of their appearance and the distinct localization complementary to the bundles support the possibility that this molecule is one contributor to the establishment and maintenance of dendritic modules. The interdigitating relationship between regions of high OCAM immunoreactivity and the dendritic bundles in layer 1 suggests that OCAM may have a repellent influence on the formation of these bundles.