Electrophysiological analysis of cochlear Na transport mechanism

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K18734
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 56050:Otorhinolaryngology-related
• Research Institution: Kyushu University
• Principal Investigator: Yoshida Takamasa 九州大学, 医学研究院, 共同研究員 (50600912)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 蝸牛 / 聴覚 / 電気生理 / ラセン靱帯

Outline of Final Research Achievements

Endocochlear potential (EP) is important for hearing. In vivo, spiral ligament in the lateral cochlear wall has a Na-dependent positive resting membrane potential which is an essential component for EP. However, the molecular basis of the Na channel in the ligament remains to be identified. In this study, we successfully recorded its membrane potential in vitro for the first time using acutely isolated tissue fragments. Ionic and drug sensitivities of the potential were obtained, which would be useful for identification of the Na channel. Also, this method would be applicable to other animal models.

Free Research Field

耳鼻咽喉科学

Academic Significance and Societal Importance of the Research Achievements

内耳蝸牛の内リンパ液が持つ+80mVもの高電位は、聴覚の高い感受性を支える電池としての役割を持ち、その破綻は難聴を惹起する。この生体電池の電源として不可欠の役割を担う「ラセン靱帯」は、in vivoにおいてプラスの静止膜電位という特異な性質を有するが、その成立機序は未解明である。本研究課題では、ラセン靱帯の静止膜電位をin vitroで実測することに初めて成功した。今後、各種モデル動物に応用可能な手法であり、内耳性難聴の病態理解や、軟膏疾患に対する治療法の開発に寄与すると考えらえる。