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Damage-evoked signals in cochlear neurons and supporting cells
Megan Beers Wood1, Nate Nowak1,2, Paul Albert Fuchs1
1The Center for Hearing and Balance, Otolaryngology-Head and Neck Surgery, Baltimore, MD, United States.
Frontiers in Neurology
|February 29, 2024
Summary
Damage to the cochlea can cause painful hyperacusis (noxacusis) transmitted by type II cochlear afferents. Epithelial calcium waves, triggered by ATP from damaged cells, are central to this cochlear pathology.
Area of Science:
- Neuroscience
- Otolaryngology
- Cell Biology
Background:
- Cochlear damage can cause hyperacusis (noxacusis), a painful condition.
- Type II cochlear afferents, similar to somatic nociceptive C-fibers, may transmit pain signals.
- Epithelial calcium waves, mediated by extracellular ATP, are implicated in cochlear damage and pathology.
Purpose of the Study:
- To investigate the role of type II cochlear afferents and epithelial calcium waves in cochlear pathology, particularly hyperacusis.
- To understand the mechanisms underlying damage-evoked signaling in the cochlea.
Main Methods:
- Recording damage-evoked signals in type II afferents and cochlear epithelial cells using cochlear explants or semi-intact otic capsules.
- Employing intracellular electrical recording, fluorescent calcium indicators, and intrinsic fluorescent signal visualization.
Main Results:
- Type II afferents are excited by ATP released from damaged epithelia.
- Damage elicits spreading calcium waves within cochlear epithelia, mediated by extracellular ATP and intracellular calcium release.
- Prior noise-induced hearing loss results in prolonged, repetitive activity in type II neurons and surrounding epithelia.
Conclusions:
- The genesis and propagation of epithelial calcium waves are central to cochlear pathology and hyperacusis.
- Type II cochlear afferents play a significant role in transmitting pain signals associated with cochlear damage.
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