Analysis of perilymphatic glutamate by in vivo microdialysis study

通过体内微透析研究分析外淋巴谷氨酸

• 批准号: 09671754
• 负责人: MATSUDA Keiji
• 金额: $ 1.92万
• 依托单位: Miyazaki Medical College
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1998
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09671754/
• 关键词: glutamate; microdialysis; perilymph; high potassium; ischemia; glutamate transporter; kanamycin; 虚血; マイクロダイアリシス; オンライン; カルシウム依存; AICA; GLAST

We applied microdialysis technique to investigate the perilymphatic glutamate.(1) The time course of changes in perilymphatic glutamate release and their Ca^<2+>-dependency were studied in the guinea pig cochlea during high K^+-evoked depolarization. Two peaks of glutamate increase were found in response to perfusion for 10 min. In the absence of Ca^<2+> the first peak was diminished, whereas the inhibition of the second peak was minimal.(2) The dynamic changes in perilymphatic glutamate and cochlear blood flow were studied in the guinea pig cochlea during occulusion of anterior inferior cerbellum artery (AICA). The result of this study indicate that the glutamate regulating system in the cochlea is dependnt on cochlear blood flow.(3) The time course of changes in perilymphatic glutamate were observed during the application of kanamycin and ethacrynic acid, which are known to damage the hair cells in the inner ear. In guinea pigs receiving a loading dose of 800 mg/kg of kanamycin subcutaneously, followed three hours later by an intravenous injection of 40 mg/kg of ethacrynic acid, a marked glutamate release was clearly found about 2 hours after the injection of ethacrynic acid. The present findings provideadditional evidence that glutamate acts as an aggravating factor in aminoglycoside-inducedototoxicity.Kanamycin (KM) -induced changes in the gene expression for glutamate-aspartatetransporter (GLAST) in the rat cochlea were analyzed by Northern blotting. With theadministration of KM (600 mg/kg/day) once daily for 20 days, the expression of GLAST mRNAgradually increased and reached a peak on day 20. Although the expression of GLAST mRNA remained at a high level at 12 days after the completion of the KM treatment, it then fellto the normal level within 2 months. The present findings suggest that during the KMadministration, high concentrations of extracellular glutamate released by collapsing haircells induced GLAST mRNA expression.

应用微透析技术研究外淋巴谷氨酸的变化。(1)在高钾诱发的豚鼠耳蜗去极化过程中，研究了外淋巴谷氨酸释放的时程变化及其Ca^<2+>依赖性。灌流10分钟后，谷氨酸增加出现两个峰值。在缺乏Ca^<2+>的情况下，第一个峰值减弱，而第二个峰值的抑制作用最小。(2)本文观察了豚鼠小脑前下动脉（AICA）闭塞时耳蜗外淋巴谷氨酸（Glu）和耳蜗血流量的动态变化。本研究结果表明，耳蜗中的谷氨酸调节系统依赖于耳蜗血流。(3)在应用卡那霉素和依他尼酸期间观察外淋巴谷氨酸变化的时间过程，已知这两种物质会损伤内耳毛细胞。在豚鼠皮下接受800 mg/kg负荷剂量的卡那霉素，3小时后静脉注射40 mg/kg依他尼酸，在注射依他尼酸后约2小时清楚地发现显著的谷氨酸释放。本研究采用北方印迹法分析了卡那霉素（KM）对大鼠耳蜗谷氨酸-谷氨酸转运体（GLAST）基因表达的影响。KM（600 mg/kg/d）灌胃20 d后，GLAST mRNA表达逐渐增加，第20 d达到高峰。KM处理后12 d，GLAST mRNA表达仍维持在较高水平，但2个月后下降至正常水平。目前的研究结果表明，在KM给药期间，毛细胞塌陷释放的高浓度细胞外谷氨酸诱导GLAST mRNA表达。

项目成果

Keiji Matsuda, Yuto Ueda, Atsushi Haruta, Tetsuya Tono and Shizuo Komune: "High potassium-induced glutamate release in the cochlea : In vivo microdialysis study combined with on-line enzyme fluorometric detection of glutamate." Brain Res.794 (2). 343-346

Keiji Matsuda、Yuto Ueda、Atsushi Haruta、Tetsuya Tono 和 Shizuo Komune：“高钾诱导的耳蜗中谷氨酸释放：体内微透析研究与谷氨酸在线酶荧光检测相结合。”

K.Matsuda, Y.Ueda, A.Haruta, T.Tono, S.Komune: "High potassium-induced glutamate release in the cochlea : in vivo microdialysis study combined with on-line enzyme fluorometric detection of glutamate." Brain Res.794(2). 343-346 (1998)

K.Matsuda、Y.Ueda、A.Haruta、T.Tono、S.Komune：“高钾诱导的耳蜗谷氨酸释放：体内微透析研究与谷氨酸在线酶荧光检测相结合。”

K.Matsuda, Y.Ueda, A.Haruta, T.Tono, S.Komune: "High potassium-induced glutamate release in the cochlea: In vivo microdialysis study combined with on-line enzyme fluorometric detection of glutamate." Brain Res.794(2). 343-346 (1998)

K.Matsuda、Y.Ueda、A.Haruta、T.Tono、S.Komune：“高钾诱导的耳蜗谷氨酸释放：体内微透析研究与谷氨酸在线酶荧光检测相结合。”

A.Haruta, K.Matsuda, T.Tono, S.Komune, A.Matsubara, S.Usami: "Changes of Perilymphatic Glutamate and Cochlear Blood Flow following Ischemia." Acta Otolaryngol.(in press). (1998)

A.Haruta、K.Matsuda、T.Tono、S.Komune、A.Matsubara、S.Usami：“缺血后外淋巴谷氨酸和耳蜗血流的变化”。

K.Matsuda, Y.Ueda, T.Doi, T.Tono, A.Haruta, K.Toyama, S.Komune: "Increase in glutamate-aspartate transporter (GLAST) mRNA during kanamycin-induced cochlear insult in rats." Hear. Res.in press. (1999)

K.Matsuda、Y.Ueda、T.Doi、T.Tono、A.Haruta、K.Toyama、S.Komune：“卡那霉素诱导大鼠耳蜗损伤期间谷氨酸-天冬氨酸转运蛋白 (GLAST) mRNA 增加。”