2023-07-04 リンショーピング大学
◆内耳の毛細胞は音波を電気信号に変換し、脳に伝える役割を果たしています。その信号にはAC信号とDC信号がありますが、DC信号の機能はまだ解明されていませんでした。ハキジマナ氏の研究では、有害な音によってDC信号の極性が変化することが明らかになりました。この信号は耳の健康状態を示す指標となる可能性があります。
◆この発見は、有害な音による聴覚損失の診断にDC信号を活用する新たな研究に貢献することが期待されています。これまで解釈や測定方法が不明だったため、この問題の解決に向けて重要な一歩となります。
<関連情報>
- https://liu.se/en/news-item/how-the-ear-can-inform-the-brain-of-whether-hearing-is-impaired
- https://link.springer.com/article/10.1007/s00018-023-04809-5
和声電位の極性は耳の健康状態を符号化する。 The summating potential polarity encodes the ear health condition
Pierre Hakizimana
Cellular and Molecular Life Sciences Published:24 May 2023
DOI:https://doi.org/10.1007/s00018-023-04809-5
Abstract
The summating potential (SP), the DC potential which, along with the AC response, is produced when the hair cells convert the vibrational mechanical energy of sound into electrical signals, is the most enigmatic of the cochlear potentials because its polarity and function have remained elusive for more than seven decades. Despite the tremendous socioeconomic consequences of noise-induced hearing loss and the profound physiological importance of understanding how loud noise exposure impairs the hair cell receptor activation, the relationship between the SP and noise-induced hearing impairment remains poorly characterized. Here, I show that in normally hearing ears, the SP polarity is positive and its amplitude relative to the AC response grows exponentially across frequencies, and becomes negative and decreases exponentially across frequencies following noise-induced hearing injury. Since the SP is thought to be generated by K+ outflow down the gradient through the hair cell basolateral K+ channels, the SP polarity switch to negative values is consistent with a noise-induced shift in the operating point of the hair cells.
