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Updated: May 15, 2026
09:51
Cochlear Surface Preparation in the Adult Mouse
Published on: November 6, 2019
Noise-induced alterations in cochlear mechanics, electromotility, and cochlear amplification
Stefan Jacob1, Cecilia Johansson, Anders Fridberger
1Center for Hearing and Communication Research, Department of Clinical Science, Intervention, and Technology, Karolinska Institutet, Stockholm, Sweden.
Pflugers Archiv : European Journal of Physiology
|December 19, 2012
Summary
Loud sounds can cause temporary hearing loss by affecting cochlear mechanics. Brief loud noise exposure in guinea pigs led to reduced amplification and increased calcium, suggesting decreased stiffness contributes to temporary threshold shifts.
Area of Science:
- Auditory Neuroscience
- Mechanobiology
- Otoacoustic Emissions
Background:
- Loud sound exposure is a common cause of temporary threshold shifts (TTS), a transient decrease in hearing sensitivity.
- The precise physiological mechanisms underlying TTS remain incompletely understood.
- Investigating these mechanisms is crucial for developing strategies to prevent or treat noise-induced hearing loss.
Purpose of the Study:
- To investigate the effects of acoustic overstimulation on the mechanical properties of the low-frequency cochlea in guinea pigs.
- To elucidate the cellular and mechanical changes associated with temporary threshold shifts.
- To understand the role of cochlear amplification in the initial response to loud sound.
Main Methods:
- Acoustic overstimulation was applied to the low-frequency regions of the guinea pig cochlea.
- Sound-evoked and electrically evoked displacements were measured using laser interferometry.
- Changes in cytoplasmic calcium levels in hair cells and supporting cells were assessed.
- Cochlear amplification measures were analyzed before and after sound exposure.
Main Results:
- Brief loud sound exposure induced an increased phase lag and a frequency-specific increase in sound-evoked displacement.
- Electrically evoked motion was reduced, correlating with decreased cochlear amplification.
- Overstimulation led to elevated cytoplasmic calcium levels in cochlear hair cells and supporting cells.
- These mechanical and cellular changes recovered within 30-40 minutes.
Conclusions:
- Reduced organ of Corti stiffness is a likely contributor to temporary threshold shifts following acoustic overstimulation.
- Changes in hair cell and supporting cell calcium levels may play a role in the observed mechanical alterations.
- The findings provide insights into the immediate mechanical consequences of loud sound exposure on cochlear function.
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