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Cochlear outer hair cell bending in an external electric field
G I Frolenkov1, F Kalinec, G A Tavartkiladze
1Section on Structural Cell Biology, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland 20892, USA.
Biophysical Journal
|September 1, 1997
Summary
Outer hair cells (OHCs) in the cochlea exhibit bending movements in response to electric fields, in addition to previously known length changes. This bending, sharing the same mechanism as length changes, may impact cochlear micromechanics.
Area of Science:
- Auditory Neuroscience
- Cellular Biophysics
- Mechanobiology
Background:
- Outer hair cells (OHCs) are crucial for hearing, exhibiting electromotility.
- Electromotility is linked to voltage-dependent structural changes in the OHC lateral membrane.
Purpose of the Study:
- To investigate OHC shape changes, specifically bending, induced by low-frequency electric stimulation.
- To elucidate the mechanism and implications of OHC electromotility.
Main Methods:
- Utilized a high-resolution motion analysis system to observe isolated guinea pig OHCs.
- Applied low-frequency (2-3 Hz) external electric stimulation.
- Investigated the effect of sulfhydryl reagents (p-chloromercuriphenylsulfonic acid, p-hydroxymercuriphenylsulfonic acid) on OHC movements.
Main Results:
- OHCs displayed significant bending movements (up to 0.7 microm peak-to-peak) when electric field gradients were perpendicular to the cell axis.
- Both longitudinal and bending movements were inhibited by specific sulfhydryl reagents, suggesting a shared underlying mechanism.
- OHC bending is proposed to result from localized charge separation across the lateral plasma membrane.
Conclusions:
- OHCs exhibit novel bending motility in response to electric fields.
- This bending shares a common mechanism with longitudinal electromotility, likely involving membrane charge dynamics.
- OHC bending may contribute to radial distortions within the cochlear sensory epithelium and influence the micromechanics of the organ of Corti.