Regeneration of Vestibular Otolith Afferents after Ototoxic Damage
Open Access
- 15 March 2006
- journal article
- research article
- Published by Society for Neuroscience in Journal of Neuroscience
- Vol. 26 (11), 2881-2893
- https://doi.org/10.1523/jneurosci.3903-05.2006
Abstract
Regeneration of receptor cells and subsequent functional recovery after damage in the auditory and vestibular systems of many vertebrates is well known. Spontaneous regeneration of mammalian hair cells does not occur. However, recent approaches provide hope for similar restoration of hearing and balance in humans after loss. Newly regenerated hair cells receive afferent terminal contacts, yet nothing is known about how reinnervation progresses or whether regenerated afferents finally develop normal termination fields. We hypothesized that neural regeneration in the vestibular otolith system would recapitulate the topographic phenotype of afferent innervation so characteristic of normal development. We used an ototoxic agent to produce complete vestibular receptor cell loss and epithelial denervation, and then quantitatively examined afferent regeneration at discrete periods up to 1 year in otolith maculas. Here, we report that bouton, dimorph, and calyx afferents all regenerate slowly at different time epochs, through a progressive temporal sequence. Furthermore, our data suggest that both the hair cells and their innervating afferents transdifferentiate from an early form into more advanced forms during regeneration. Finally, we show that regeneration remarkably recapitulates the topographic organization of afferent macular innervation, comparable with that developed through normative morphogenesis. However, we also show that regenerated terminal morphologies were significantly less complex than normal fibers. Whether these structural fiber changes lead to alterations in afferent responsiveness is unknown. If true, adaptive plasticity in the central neural processing of motion information would be necessitated, because it is known that many vestibular-related behaviors fully recover during regeneration.Keywords
This publication has 61 references indexed in Scilit:
- Changes in the Three-Dimensional Angular Vestibulo-Ocular Reflex following Intratympanic Gentamicin for Ménière's DiseaseJournal of the Association for Research in Otolaryngology, 2002
- Functional Recovery of Anterior Semicircular Canal Afferents following Hair Cell Regeneration in BirdsJournal of the Association for Research in Otolaryngology, 2002
- Differential central projections of vestibular afferents in pigeonsJournal of Comparative Neurology, 1996
- Functional architecture of vestibular primary afferents from the posterior semicircular canal of a turtle, Pseudemys (Trachemys) scripta elegansJournal of Comparative Neurology, 1994
- Morphological correlates of functional recovery in the chicken inner ear after gentamycin treatmentJournal of Comparative Neurology, 1993
- Hair cell regeneration in the avian vestibular epitheliumExperimental Neurology, 1992
- An electrophysiological comparison of solitary type I and type II vestibular hair cellsNeuroscience Letters, 1990
- Morphological changes in afferent vestibular hair cell synapses during the postnatal development of the catJournal of Neurocytology, 1979
- The Vestibular Sensory Epithelia in the Cat Labyrinth and Their Reactions in Chronic Streptomycin IntoxicationActa Oto-Laryngologica, 1962
- Embedding in Epoxy Resins for Ultrathin Sectioning in Electron MicroscopyStain Technology, 1960