Miranda E, Almonacid J A, Rodriguez S, Perez J, Hein S, Cifuentes M, Fernández-Llebrez P, Rodríguez E M
Departamento de Biología Animal, Facultad de Ciencias, Universidad de Málaga, 29071 Málaga, Spain.
Microsc Res Tech. 2001 Mar 1;52(5):541-51. doi: 10.1002/1097-0029(20010301)52:5<541::AID-JEMT1039>3.0.CO;2-W.
The molecular organization of Reissner's fiber (RF), the structure of its proteins, and the permanent turnover of these proteins are all facts supporting the possibility that RF may perform multiple functions. There is evidence that CSF-soluble RF-glycoproteins may occur under physiological conditions. The present investigation was designed to investigate the probable existence within the CNS of specific binding sites for RF-glycoproteins. Three experimental protocols were used: (1) immunocytochemistry of the CNS of bovine fetuses using anti-idiotypic antibodies, raised against monoclonal antibodies developed against bovine RF-glycoproteins; (2) in vivo binding of the RF glycoproteins, perfusing into the rat CSF 125I-labeled RF-glycoproteins, or grafting SCO into a lateral ventricle of the rat; (3) in vitro binding of unlabeled RF-glycoproteins to rat and bovine choroid plexuses maintained in culture. One of the anti-idiotypic antibody generated by a Mab raised against RF-glycoproteins binds to choroidal cells. Furthermore, binding of RF-glycoproteins to the rat choroid plexus was obtained when: (1) the choroid plexus was cultured in the presence of unlabeled RF-glycoproteins; (2) the concentration of soluble RF-glycoproteins in the CSF was increased by isografting SCOs into a lateral ventricle; (3) radiolabeled glycoproteins were perfused into the ventricular CSF. This evidence suggests that the apical plasma membrane of the ependymal cells of the choroid plexus has specific binding sites for RF-glycoproteins, of unknown functional significance. The radiolabeled RF-glycoproteins perfused into the rat CSF also bound to the paraventricular thalamic nucleus, the floor of the Sylvian aqueduct and of the rostral half of the fourth ventricle, and the meninges of the brain and spinal cord. The labeling of the paraventricular thalamic nucleus points to a functional relationship between this nucleus and the SCO. The possibility that the SCO may be a component of the circadian timing system is discussed.
内耳膜迷路纤维（RF）的分子组织、其蛋白质结构以及这些蛋白质的持续更新，均支持RF可能执行多种功能这一可能性。有证据表明，脑脊液可溶性RF糖蛋白可能在生理条件下出现。本研究旨在调查中枢神经系统（CNS）内是否可能存在RF糖蛋白的特异性结合位点。采用了三种实验方案：（1）使用抗独特型抗体对牛胎儿的中枢神经系统进行免疫细胞化学分析，该抗独特型抗体是针对针对牛RF糖蛋白产生的单克隆抗体而制备的；（2）RF糖蛋白的体内结合，将125I标记的RF糖蛋白灌注到大鼠脑脊液中，或将脉络丛器官（SCO）移植到大鼠侧脑室；（3）未标记的RF糖蛋白与培养的大鼠和牛脉络丛的体外结合。由针对RF糖蛋白产生的单克隆抗体产生的一种抗独特型抗体与脉络丛细胞结合。此外，当以下情况时，可观察到RF糖蛋白与大鼠脉络丛的结合：（1）在未标记的RF糖蛋白存在下培养脉络丛；（2）通过将SCO移植到侧脑室来增加脑脊液中可溶性RF糖蛋白的浓度；（3）将放射性标记的糖蛋白灌注到脑室脑脊液中。这一证据表明，脉络丛室管膜细胞的顶端质膜具有RF糖蛋白的特异性结合位点，其功能意义尚不清楚。灌注到大鼠脑脊液中的放射性标记RF糖蛋白还与室旁丘脑核、中脑导水管底部和第四脑室前半部分的底部以及脑和脊髓的脑膜结合。室旁丘脑核的标记表明该核与SCO之间存在功能关系。文中讨论了SCO可能是昼夜节律计时系统组成部分的可能性。
