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Inhibition of gap junctional coupling in cochlear supporting cells by gentamicin
1Institute of Biophysics, University of Hannover, Germany.
Pflugers Archiv : European Journal of Physiology
|December 11, 1999
Summary
Gentamicin damages hearing by disrupting gap junctional coupling in cochlear supporting cells, likely via free radical production. This impairs potassium buffering crucial for outer hair cell function.
Area of Science:
- Ototoxicity research
- Cellular electrophysiology
- Auditory neuroscience
Background:
- Gap junctional coupling in cochlear supporting cells facilitates potassium buffering for outer hair cells (OHCs).
- Aminoglycosides, like gentamicin, are known to cause ototoxicity, primarily targeting OHCs.
Purpose of the Study:
- To investigate the role of Hensen cells, a type of cochlear supporting cell, in gentamicin-induced ototoxicity.
- To determine if gentamicin affects the gap junctional coupling of Hensen cells.
Main Methods:
- Isolated Hensen cell pairs were superfused with gentamicin solutions.
- The double whole-cell patch-clamp technique was employed to measure membrane potential and gap junctional conductance.
Main Results:
- Gentamicin (10 microM) significantly inhibited gap junctional conductance in Hensen cells by approximately 90%.
- Membrane potential remained stable at -27 mV, suggesting specific inhibition of gap junctions.
- The inhibitory effect of gentamicin was mitigated by catalase, indicating a role for free radicals.
Conclusions:
- Gentamicin impairs gap junctional coupling in cochlear supporting Hensen cells, likely through free radical generation.
- This disruption interferes with spatial potassium buffering, potentially contributing to outer hair cell dysfunction and aminoglycoside-induced hearing loss.