水チャネルの内耳局在と内耳水代謝に対する役割に関する研究

为探讨内耳水的稳态，本研究对耳蜗外侧壁AQP-2、-3、-4、-6、-7、-8、-9和V2-R的定位进行了研究，并进行了分子生物学和组织化学研究。所用动物为Wistar大鼠。在分子生物学研究中，研究了AQP-2、-3、-4、-6、-7、-8、-9和V2-R mRNA的表达。在组织化学研究中，应用激光共聚焦显微镜观察AQP-2、-3、-4、-6、-7、-8、-9和V2-R的定位，发现AQP-2、-3、-4、-6、-7、-9和V2-R mRNA在大鼠耳蜗中均有表达。组织化学显示AQP-2、AQP-3和V2-R蛋白表达于血管纹基底细胞。AQP-6蛋白在血管纹的所有细胞中均有表达。AQP-4在血管纹外侧壁不表达，AQP-7、AQP-9在边缘细胞顶端表达，AQP-2、AQP-3和V2-R在基底细胞表达，位于外淋巴系统和内淋巴系统的交界处。由于渗透压通常被认为在内淋巴室中较高，因此水可能通过这些水通道进入细胞外空间。推测细胞外间隙中的水通过Na-K-Cl协同转运蛋白进入边缘细胞，并通过位于顶膜的AQP-7和AQP-9流出。

In order to evaluate the homeostasis of water in the inner ear, localization of AQP-2,-3,-4,-6,-7,-8,-9 and V2-R in the lateral wall of the cochlea were investigated and water homeostasis of the cochlea was discussed.Molecular biological and histochemistry studies were performed. Animals used were Wistar rats. In molecular biological study, the expression of AQP-2,-3,-4,-6,-7,-8,-9 and V2-R mRNAs was investigated. In histochemistry study, localization of AQP-2,-3,-4,-6,-7,-8,-9 and V2-R was observed by a Confocal laser microscopy.AQP-2,-3,-4,-6,-7,-9 and V2-R mRNAs were expressed in the rat cochlea. Histochemistry revealed that Proteins of AQP-2,-3, and V2-R were expressed in the basal cells on the stria vascularis. AQP-6 protein was detected in the all cells of the stria vascularis. On the other hand, AQP-4 was not expressed in the lateral wall of the stria vascularis.AQP-7,-9 were expressed in the apical site of the marginal cells.AQP-2,-3 and V2-R is localized in the basal cells, located at the boundary between the perilymphatic system and the endolymphatic system. Since osmolality is generally thought to be higher in the endolymphatic compartment, water might enter into the extracellular space via these water channels. Water in the extracellular space is speculated to enter the marginal cells through Na-K-Cl cotransporter and to flow out through AQP-7 and-9 located in the apical membrane.