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Research on sodium transport in the endolymphatic sac

内淋巴囊钠转运的研究

基本信息

批准号：
13671783
负责人：
MORI Nozomu
金额：
$ 2.24万
依托单位：
Kagawa University(Faculty of Medicine)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2003
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13671783/
关键词：
endolymphatic sac epithelial cell sodium ion transport patch clamp technique SFBI AM fluorescence measurement intracellular calcium mitochondria stain epithelial cell sodium transport fluorescence measurement SFBI AM mitochondria

项目摘要

(Study on non-selective cation channel in the ES) The properties of a non-selective cation channel in the endolymphatic sac (ES) were investigated using patch clamp technique. The channel currents were measured in freshly isolated epithelial cells from the intermediate portion of the endolymphatic sac (ES) in the guinea pig by the single-channel recording technique. The non-selective cation channel had a conductance of 24.0? 1.3pS (n=8). The relative ionic permeability of the channel was in the order K^+=Na^>Ca^<2+>>Cl^-. ATP (1 mM) activated the channel at intracellular Ca^<2+> concentrations from 0.6 iM to 10iM. The results suggest that the non-selective cation channel in the ES may contribute to the regulation of ionic balance and volume of the ES by absorbing Na^+ under certain pathological situations increasing the intracellular Ca^<2+> concentration.(Microfluorometrical study on Na+ transport in the ES) The properties of Na+ transport in the ES epithelial cells were investigated using SFBI/AM fluorescence measurement. The intracellular Na concentration was increased by the suppresion of Na^+-K^+ ATPase such as the application with K^+-free solution and ouabain. ES epithelial cells in the intermediate portion were classified into two types, based on the activity of Na^+-K^+ ATPase. Two type cells were almost equally distributed in number. The epithelial cells with a higher activity corresponded to strongly mitochondria-stained cells (type 1cells). The results indicates that type 1cells play important roles in sodium transport of the ES. The simulation of Na transport capacity in the ES epithelial cells on the basis of the present experimental results supports the morphological data in the experimentally induced endolympatic hydrops.

用膜片钳技术研究了内淋巴囊（ES）非选择性阳离子通道的特性。用单通道记录技术，测定了新鲜分离的豚鼠内淋巴囊（ES）中间部上皮细胞的通道电流。非选择性阳离子通道的电导为24.0？1.3pS（n=8）。通道的相对离子渗透性为K^+=Na^>Ca^<2+>>Cl^-。ATP（1 mM）在细胞内Ca^<2+>浓度为0.6 μ M至10 μ M时激活该通道。结果提示，在某些病理状态下，ES细胞的非选择性阳离子通道可能通过吸收Na^+，增加细胞内Ca^2+浓度，从而调节ES细胞的离子平衡和容积。（ES细胞Na+转运的显微荧光研究）用SFBI/AM荧光测量法研究了ES上皮细胞Na+转运的特性。通过抑制Na^+-K^+ ATP酶，如应用无K^+溶液和哇巴因，使细胞内Na浓度升高。根据Na^+-K^+ ATP酶的活性，将中间部ES上皮细胞分为两类。两种类型细胞的数量几乎相等。具有较高活性的上皮细胞对应于强染色的细胞（1型细胞）。结果表明，1型细胞在ES钠转运中起重要作用。根据本实验结果，ES上皮细胞中Na转运能力的模拟支持实验诱导的内淋巴水肿的形态学数据。