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Chick hair cells do not exhibit voltage-dependent somatic motility
David Z Z He1, Kirk W Beisel, Lin Chen
1Hair Cell Biophysics Laboratory, Boys Town National Research Hospital, 555 North 30th Street, Omaha, NE 68131, USA. hed@boystown.org
The Journal of Physiology
|January 16, 2003
Summary
Avian hair cells lack somatic motility, challenging the belief that outer hair cell electromotility is essential for hearing. This suggests the active process in bird hearing may occur in the hair cell stereocilia.
Area of Science:
- Auditory Neuroscience
- Cellular Biophysics
- Comparative Anatomy
Background:
- Cochlear hair cells are crucial for hearing sensitivity and frequency selectivity.
- Mammalian outer hair cells (OHCs) exhibit voltage-dependent electromotility, forming the basis of cochlear amplification.
- Avian basilar papilla hair cells (tall and short) are analogous to mammalian inner and outer hair cells, respectively.
Purpose of the Study:
- To investigate somatic electromotility in avian hair cells.
- To determine if avian hair cells exhibit voltage-dependent length changes.
- To identify the location of the active process in avian hearing.
Main Methods:
- Direct measurement of voltage-dependent length changes in tall and short chick hair cells using nanometre resolution.
- Whole-cell voltage-clamp and microchamber techniques.
- Measurement of non-linear capacitance as an indicator of somatic motility.
Main Results:
- Chick hair cells showed no evidence of somatic motility.
- Avian hair cells did not express non-linear capacitance.
- The study found no voltage-dependent length changes in the hair cell bodies.
Conclusions:
- The absence of somatic motility in avian hair cells suggests this mechanism is not universally required for hearing.
- The active process in avian hearing likely resides in the hair cell stereocilia, not the cell body.
- This finding challenges established models of cochlear amplification.
Keywords:
Non-programmatic