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Roles of Cl^- in cellular signal transduction

Cl^- 在细胞信号转导中的作用

基本信息

批准号：
07457024
负责人：
INAGAKI Chiyoko
金额：
$ 4.35万
依托单位：
Kansai Medical University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

项目摘要

1. Roles of intracellular Cl^- concentration ( [Cl^-] _i) in c-fos expression in the brain.Intracerebroventricular injection of ethacrynic acid that inhibits neuronal Cl^- extrusion and induces glutamate release, increased c-fos expression in hippocampal neurons in mice. Analyzes of the time courses by Northern blot and in situ hybridization showed two peaks of c-fos mRNA levels 60 min and 10-14 days after the injection of ethacrynic acid. In parallel with the time couses, levels of nerve growth factor mRNA also increased in the same brain regions.2. Roles of [Cl^-] _i in responses to beta-adrenoceptor stimulation.Adrenoceptor-mediated Cl^- transport in cultured rabbit corneal endothelium was examined using a Cl^--sensitive fluorescent dye. The corneal endothelial cells accumulated Cl^<> upon beta-adrenoceptor stimulation under the condition of low [Cl^-] _i (<30mM), but not under the conditions of [Cl^-] _i<greater than or equal>30mM,probably via acceleration of G-protein subunit dissociation followed by activation of cAMP-dependent proteinkinase and Na^+/K^+/Cl^- cotransporter.3. Role of [Cl^-] _i in responses to metabotropic glutamate receptor (mGluR) stimulation.When [Cl^-] _i was changed, stimulation of mGluRl alpha expressed in Chinese hamster ovary cells yielded different amounts of IP_3 with a peak at 20mM of [Cl^-] _i. Pertussis toxin (PTX) blocked the [Cl^-] _i-sensitive IP_3 formation suggesting that activation of mGluR-coupled PTX-sensitive G-protein is sensitive to [Cl^-] _i.4. A new [Cl^-] _i regulating system.Neuronal outwardly directed Cl^- transport system (Cl^- pump) was identified as 520 kDa protein that primarily transports Cl^- in an ATP-dependent manner to lower neuronal [Cl^-] _i when reconstituted in liposomes.

1.细胞内Cl^-浓度（[Cl^-] _i）在脑内c-fos表达中的作用脑室注射依他尼酸（ethacrynic acid）可抑制神经元Cl^-排出并诱导谷氨酸释放，增加小鼠海马神经元c-fos表达。应用北方杂交和原位杂交技术分析了注射依他尼酸后60 min和10-14 d c-fos mRNA表达的时程变化。与时间进程相平行，同一脑区神经生长因子mRNA的表达水平也随之升高. [Cl^-] i在β-肾上腺素受体刺激反应中的作用用Cl^-敏感的荧光染料检测培养的兔角膜内皮细胞中肾上腺素受体介导的Cl^-转运。在低[Cl^-] _i（<30 mM）条件下，β-肾上腺素受体刺激角膜内皮细胞后，细胞内Cl^_i增加，而在[Cl^-] _i <greater than or equal>30 mM条件下，细胞内Cl ^_i增加不明显，可能是通过G蛋白亚基解离加速，cAMP依赖的蛋白激酶和Na^+/K^+/Cl^-共转运蛋白激活. [Cl^-] _i在代谢型谷氨酸受体（mGluR）刺激反应中的作用当[Cl^-] _i改变时，刺激中国仓鼠卵巢细胞表达的mGluR 1 α产生不同量的IP_3，[Cl^-] _i在20 mM时达到峰值。百日咳毒素（PTX）阻断[Cl^-] i敏感的IP_3形成，表明mGluR偶联的PTX敏感的G蛋白的活化对[Cl^-] i敏感。一种新的[Cl^-] i调节系统：神经元外向Cl^-转运系统（Cl^- pump）是一种分子量为520 kDa的蛋白质，在脂质体中重组后，主要以ATP依赖的方式将Cl^-转运至神经元下层[Cl^-] i。