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Physiological significance of Purinergic receptor of guinea pig cochlea

豚鼠耳蜗嘌呤能受体的生理意义

基本信息

批准号：
08457448
负责人：
SUGASAWA Masashi
金额：
$ 0.96万
依托单位：
University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1998
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08457448/
关键词：
Inner ear organ of Corti Puninergic receptor ATP supparting cell Hensen cell Deiters cell hair cell モルモット P2x P2y Purinergic receptor 内有毛細胞蝸牛 Supporting cell

项目摘要

Recent finding that purinergic receptor, which is known as specific receptor to extra-cellular ATP, existed in cells of organ of Corti of guinea pig cochlea, introduces a new concept that extra-cellular ATP acts as a bio-modulator in the cochlea. In order to explicate of the physiological functions of ATP in cochlea, by using patchclamp whole cell configuration and simultaneous Ca^<2+> fluorometry, the ATP evoked cellular responses are measured.Extra-cellular ATP evoked an inward current and a simultaneous increase of intracellular free Ca^<2+> in all cells (inner hair cell, outer hair cell, Deiters cell, Hensen cell and Piller cell) of organ of Cord. Those responses were coupled to the activations of P2x and P2y receptor, respectively. Interestingly, in inner hair cells Ca^<2+> responses secondary activated Ca^<2+>-dependent potassium channel and in Hensen cells also secondary activated Ca^<2+> dependent Chloride channel.All cells except Deiters cells ; P2x receptor was located endlymphatic side of the cells. Location of P2y receptor was identified only in inner hair cells. It was placed in the base of inner hair cells.There were different patterns of purinergic response in each cells of organ of Cord suggesting that ATP act as a bio-modulator in organ of Cord in different manners.

最近在豚鼠耳蜗Corti器官细胞中发现嘌呤能受体是细胞外ATP的特异性受体，这为细胞外ATP在耳蜗中发挥生物调节剂的作用提出了新的概念。为了阐明ATP在耳蜗中的生理功能，采用膜片钳全细胞构型和同步Ca^<2+>荧光法测量了ATP引起的细胞反应。胞外ATP引起脊髓所有细胞（内毛细胞、外毛细胞、Deiters细胞、Hensen细胞和Piller细胞）向内流动，胞内游离Ca^<2+>同时升高。这些反应分别与P2x和P2y受体的激活相耦合。有趣的是，在内毛细胞中，Ca^<2+>反应继发性激活了Ca^<2+>依赖性钾通道，Hensen细胞也继发性激活了Ca^<2+>依赖性氯通道。除deiter细胞外的所有细胞；P2x受体位于细胞淋巴端。P2y受体仅在内毛细胞中定位。它被放置在内毛细胞的基部。脐带各器官细胞的嘌呤能反应模式不同，表明ATP在脐带各器官中以不同的方式发挥生物调节剂的作用。