DENDRITE-ASSOCIATED CELL ABHESION MOLECULE OBCAM IN THE HYPOTHALAMIC MAGNOCELLULAR NEURONS

阿片结合细胞黏附分子(OBCAM)是一种免疫球蛋白超家族细胞黏附分子，由三个Ig G样结构域组成。本研究表明，OBCAM特异性地定位于下丘脑视上核和室旁核大细胞神经元的树突。电子显微镜观察进一步表明，OBCAM定位于树突的血管加压素分泌神经分泌颗粒，并与树突释放的囊泡一起释放。在培养的皮质神经元中，也观察到OBCAM靶向突触后树突棘的树突干。电子显微镜观察发现，OBCAM在突触后膜和密度处聚集。交联性研究表明，OBCAM能够与另一种免疫球蛋白超家族成员蛋白Kilon发生同亲和异亲结合。

Opioid-binding cell adhesion molecule (OBCAM) is one of immunoglobulin superfamily cell adhesion molecule and consists of three IgG-like domains. In the present study, it was shown that OBCAM located specifically at the dendrites of magnocellular neurons of the hypothalamic supraoptic and paraventricular nucleus. Electron microscopic observation further showed that OBCAM was localized at vasopressin-secreting neurosecretory granules of the dendrites and released together with dendritic release of vesicles. In cultured cortical neurons, OBCAM was also observed to target to their dendritic shaft specifically at postsynaptic dendritic spine. Electron microscopic observation revealed that OBCAM was seen to accumulate at postsynaptic membrane and density. Cross-linking study demonstrated that OBCAM was able to bind homophilically each other and heterophilically with Kilon, another immunoglobulin superfamily member protein.