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Forces involved in length changes of cochlear outer hair cells
A H Gitter1, M Rudert, H P Zenner
1Sektion Physiologische Akustik, Klinik für Hals-Nasen-Ohrenheilkunde, Universität Tübingen, Germany.
Pflugers Archiv : European Journal of Physiology
|June 1, 1993
Summary
Outer hair cells generate force through electromotility, a key mechanism for cochlear mechanics. This study quantures the force generated by outer hair cells, revealing their role in hearing.
Area of Science:
- Otoacoustic emissions
- Auditory neuroscience
- Cellular mechanics
Background:
- Outer hair cells (OHCs) are crucial for the active modulation of cochlear mechanics.
- Understanding the force generated by OHCs is vital for comprehending auditory function.
Purpose of the Study:
- To quantify the force generated by outer hair cells during length changes.
- To investigate the role of electromotility in force generation within OHCs.
Main Methods:
- An in vitro method was developed to measure OHC length changes in response to voltage variations.
- Cell elongation was measured under negative pressure, with frictional effects corrected.
- Longitudinal axis compliance of OHCs was calculated, considering cell membrane water permeability.
Main Results:
- A voltage change induced proportional OHC length changes (4.4 nm/mV for an 80-micron cell).
- OHC compliance was calculated as approximately 220-240 m/N, or around 500 m/N considering water permeability.
- A 1-micrometer OHC length change requires a static force of at least 2 nN.
Conclusions:
- Electromotility in outer hair cells generates the necessary force for their mechanical function.
- This force generation mechanism is essential for the active processes within the organ of Corti.
- The findings elucidate the biophysical basis of OHC function in hearing.