Morphological consequences of acoustic trauma on cochlear hair cells and the auditory nerve

Coyat, Carolanne; Cazevieille, Chantal; Baudoux, Véronique; Larroze-Chicot, Philippe; Caumes, Bastien; González-González, Sergio

doi:10.1080/00207454.2018.1552693

Cited by 13 publications

(9 citation statements)

References 33 publications

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“…The health of an auditory system -its ability to transduce sound into electrical signals -has been assayed from the summated electrical potentials of the auditory nerve or auditory processing areas in the brain. After acoustic overstimulation there is an increase in the auditory threshold (Coyat, et al, 2018;Christie & Eberl, 2014;Housley et al, 2013;Pilati et al, 2012;Telang et al, 2010;Sendowski et al, 2004;Ma et al, 1995;Dolan & Mills, 1989;Pettigrew et al, 1984;Van Heusden & Smoorenburg, 1981) and a decrease in the sound-evoked compound action potential amplitude (Christie & Eberl, 2014;Sendowski et al, 2004;Wang et al ., 1992;Dolan & Mills, 1989;Pettigrew et al, 1984;Van Heusden & Smoorenburg, 1981). In the locust we found, firstly, that the linear displacement of the tympanum is converted into a nonlinear sigmoidal electrical response of the tympanal nerve.…”

Section: In Vivo Electrophysiological Responses Of the Auditory Nervementioning

confidence: 99%

Physiological Basis of Noise-Induced Hearing Loss in a Tympanal Ear

et al. 2020

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Acoustic overexposure, such as listening to loud music too often, results in noise-induced hearing loss. The pathologies of this prevalent sensory disorder begin within the ear at synapses of the primary auditory receptors, their postsynaptic partners and their supporting cells. The extent of noise-induced damage, however, is determined by over-stimulation of primary auditory receptors, upstream of where the pathologies manifest. A systematic characterisation of the electrophysiological function of the upstream primary auditory receptors is warranted to understand how noise-exposure impacts on downstream targets, where the pathologies of hearing loss begin. Here, we used the experimentally-accessible locust ear (male, Schistocerca gregaria) to characterise a decrease in the auditory receptor's ability to respond to sound after noise exposure. Surprisingly, after noise exposure, the electrophysiological properties auditory receptors remains unchanged, despite a decrease in the ability to transduce sound. This auditory deficit stems from changes in a specialised receptor lymph that bathes the auditory receptors-revealing striking parallels with the mammalian auditory system. Significance Statement Noise exposure is the largest preventable cause of hearing loss. It is the auditory receptors that bear the initial brunt of excessive acoustic stimulation, because they must convert excessive soundinduced movements into electrical signals, but remain functional afterward. Here we use the accessible ear of an invertebrate to-for the first time in any animal-characterise changes in auditory receptors after noise overexposure. We find that their decreased ability to transduce sound into electrical signals is, most probably, due to changes in supporting (scolopale) cells that maintain the ionic composition of the ear. An emerging doctrine in hearing research is that vertebrate primary auditory receptors are surprisingly robust, something which we show rings true for invertebrate ears too.

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Section: In Vivo Electrophysiological Responses Of the Auditory Nervementioning

confidence: 99%

Physiological Basis of Noise-Induced Hearing Loss in a Tympanal Ear

et al. 2020

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“…A contributing cause of deafness is loss of auditory hair cells (in vertebrates) through necrotic and apoptotic pathways, which can take place within 48 hours of acoustic trauma (Coyat et al, 2018;Ryals et al, 1999;Cotanche, 1987;Hamernik et al, 1984). We thus, measured the morphology of recorded auditory neurons exposed to 24 hrs of loud sound (126 dB SPL) but found no difference compared to controls.…”

Section: Morphology and Electrophysiological Properties Of The Auditomentioning

confidence: 87%

“…The health of an auditory system -its ability to transduce sound into electrical signals -has been assayed from the summated electrical activity of the auditory nerve (Compound Action Potentials (CAPs)) and hierarchical auditory processing areas through the brain (Auditory Brainstem Responses (ABRs)). After acoustic overstimulation there is an increase in the minimum sound level to get a sound-evoked electrical signal from the auditory nerve -the so-called auditory threshold (Coyat, et al, 2018;Christie & Eberl, 2014;Housley et al, 2013;Pilati et al, 2012;Telang et al, 2010;Sendowski et al, 2004;Ma et al, 1995;Dolan & Mills, 1989;Pettigrew et al, 1984;Van Heusden & Smoorenburg, 1981). This increased auditory threshold is mirrored by a decrease in the sound-evoked CAP amplitude after noise exposure (Christie & Eberl, 2014;Sendowski et al, 2004;Wang et al ., 1992;Dolan & Mills, 1989;Pettigrew et al, 1984;Van Heusden & Smoorenburg, 1981).…”

Section: In Vivo Electrophysiological Responses Of the Auditory Nervementioning

confidence: 99%

Physiological basis of noise-induced hearing loss in a tympanal ear

Warren

Fenton

Klenschi

et al. 2019

Preprint

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Acoustic overexposure, such as listening to music too loud and too often, results in noiseinduced hearing loss. The pathologies of this prevalent sensory disorder begin in the synapses of the primary auditory receptors, their postsynaptic partners and supporting cells. The extent of noise-induced damage, however, is determined by over-stimulation of primary auditory receptors. When over-stimulated, an excessive amount of positive ions flood into the primary auditory receptors, triggering the activation of ion channels and possibly disrupting their ability to encode sound. A systematic characterisation of the electrophysiological function of primary auditory receptors is warranted to understand how noise-exposure impacts on downstream targets, where the pathologies of hearing loss begin. Here, we used the experimentallyaccessible locust ear to characterise noise-induced changes in the auditory receptors. Although, we found a decrease in ability of the primary auditory neurons to encode sound, this is probably due to pathologies of their supporting cells.

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“…Pilati and collaborators described loss of myelin from 50% of rat auditory nerve axons innervating basal cochlear inner hair cell synapses, 3-4 days after acoustic trauma [47]. Moreover, increasing number of studies demonstrated that acoustic trauma leading to hearing loss also triggered auditory nerve demyelination [48] and notable morphological changes at myelin sub-domains such as nodes of Ranvier, paranodes and juxtaparanodes that were associated with the decreased conduction velocity [49]. This acoustic trauma decreased the auditory nerve conduction velocity and the myelin thickness of the fibers projecting toward the auditory brainstem [49].…”

Section: Demyelination and Hearing Lossmentioning

confidence: 99%

Myelination of the Auditory Nerve: Functions and Pathology

González-González

Cazevieille

2019

SJRR

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Myelination is essential for the rapid propagation of action potentials along axons in both the central and peripheral nervous systems, and the Schwann cells are the responsible of myelin sheath production in the peripheral nervous system. In the cochlea, sensory hair cells and neurons are in close association with several types of glial cells. Whereas hair cells are surrounded by supporting cells, spiral ganglion neuron axons are myelinated by Schwann cells. This myelin contributes to axonal protection and allows for efficient action potential transmission along the auditory nerve. Because in the last decade, myelin research has been notably focusing on the molecular and cellular mechanism of demyelination process and the associated axonal loss, in this review we summarize the role of the myelin sheath in auditory nerve and how Schwann cell demyelination results in a reduction in the velocity of action potential propagation, and an increase in nerve conduction vulnerability.

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Morphological consequences of acoustic trauma on cochlear hair cells and the auditory nerve

Cited by 13 publications

References 33 publications

Physiological Basis of Noise-Induced Hearing Loss in a Tympanal Ear

Physiological Basis of Noise-Induced Hearing Loss in a Tympanal Ear

Physiological basis of noise-induced hearing loss in a tympanal ear

Myelination of the Auditory Nerve: Functions and Pathology

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