Neuroreport · 1998 · 435 citations · 4 references
MedicineAudiologyNeuroscienceCellular NeurobiologyHearing ScienceNeurotoxicologyAuditory NeurobiologyAuditory NeurophysiologyCochlear NeurobiologyCochlear NeuroscienceHearing LossNoise-induced Hearing DamageCochlear SynapsesCochlear TraumaNoise-induced Auditory Nerve DamageNoise-induced Cochlear DamageNoise-induced Cochlear InjuryNoise-induced Synaptic DamageNoise-induced Temporary Threshold ShiftRecovery From Temporary Threshold Shift
Traumatic noise exposure in guinea pigs produced up to Θ dB hearing loss. The study aimed to test whether excessive glutamate release from inner hair cells causes synaptic damage after noise trauma. The authors evaluated the protective effect of the glutamate antagonist kynurenate on noise‑induced hearing loss. Noise trauma caused acute loss of IHC–auditory nerve synapses, and treatment with kynurenate markedly protected against dendritic damage, indicating its key role in hearing loss and revealing a rapid synaptic repair process that contributes to recovery of temporary threshold shifts.
GUINEA-PIGS were exposed to a traumatic sound inducing up to Θ dB hearing loss. Beside the well described mechanical damage to outer hair cells, a total disruption of inner hair cell (IHC)–auditory nerve synapses was acutely observed within the traumatized area. To test the hypothesis that synaptic damage is due to an excessive release of glutamate by the IHCs, we examined the protective effect of the glutamate antagonist kynurenate on noise-induced hearing loss. The high degree of protection observed with kynurenate attests that dendritic damage is an important component in noise-induced hearing loss. Moreover, we demonstrate that a synaptic repair mechanism occurring within the first few days post-exposure is partly responsible for the recovery of temporary threshold shifts after an acoustic trauma.
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