Cochlear function in Prestin knockout mice

• DOI: 10.1113/jphysiol.2004.069559
• Publication Date: 2004-08-20T02:54:50Z
• Authors: M. A. Cheatham; K. H. Huynh; J. Gao; J. Zuo; P. Dallos
• Keywords: Prestin; Knockout mouse; Gene knockout; Transduction (biophysics)

Gross-potential recordings in mice lacking the Prestin gene indicate that compound action potential (CAP) thresholds are shifted by approximately 45 dB at 5 kHz and 60 33 kHz. However, order to conclude outer hair cell (OHC) electromotility is associated with cochlear amplifier, frequency selectivity must be evaluated integrity of OHC's forward transducer ascertained. The present report demonstrates no CAP tuning curves recorded homozygotes. In addition, input-output functions responses knockout approach those controls high levels where amplifier has little influence. Although microphonic remains 12 below wild-type even highest levels, this deficit thought reflect losses prestin. A change OHC transduction not implied because display non-linear similar controls. For example, homozygotes exhibit a bipolar summating (SP) positive frequencies; negative low frequencies. Measurement intermodulation distortion also shows cubic difference tone, 2f(1)-f(2), 20 down from primaries both their Because OHCs sole generators SP 2f(1)-f(2) originate transduction, these data support idea degraded Finally, application AM1-43, which initially enters cells through channels, produces fluorescence indicating channel activity inner cells.