Cochlear efferents in developing adult and pathological conditions

Nouvian, Régis; Eybalin, Michel; Puel, Jean–Luc

doi:10.1007/s00441-015-2158-z

Cited by 34 publications

(37 citation statements)

References 79 publications

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“…No studies that have observed responses of the olivocochlear efferent system in PD were found. However, OAEIE is known to reflect the functioning of the medial olivocochlear efferent system (MOES), which inhibits EHC contractile responses in the presence of competitive noise (18) and its activity mediated by cholinergic and gabaergic neurotransmitters (19) . On the other hand, cochlear responses are also influenced by the lateral olivocochlear efferent system (LOES), which has dopamine as one of its main neurotransmitters (19) .…”

Section: Discussionmentioning

confidence: 99%

Efeito da levodopa na mecânica coclear e no sistema auditivo eferente de indivíduos com doença de Parkinson

Lopes

Melo

Corona

et al. 2019

CoDAS

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RESUMO Objetivo Analisar o efeito da levodopa na dinâmica coclear, bem como na via eferente olivococlear medial de indivíduos com doença de Parkinson idiopática (DP). Método Indivíduos com e sem DP, acompanhados em um hospital universitário, realizaram a pesquisa das emissões otoacústicas por produto de distorção (EOAPD) e do efeito inibitório das EOAPD (EIEOA) na presença de ruído contralateral. Foram estabelecidas as medidas de correlação entre os resultados das EOAPD e do EIEOA com estágio Hoehn&Yahr (H&Y), dose diária de levodopa e tempo de diagnóstico da DP. Além disso, as medidas eletroacústicas foram comparadas entre os indivíduos sem DP e com DP, estratificados de acordo com a dose de levodopa administrada diariamente. Resultados Foi identificada correlação fraca e negativa entre a amplitude das EOAPD com a dose diária de levodopa e correlações positivas, de força moderada e fraca, entre o EIEOA com a dose diária de levodopa e o tempo de diagnóstico da DP, respectivamente. A amplitude das EOAPD foi maior nos indivíduos com DP em uso de levodopa ≤ 600 miligramas quando comparada à de indivíduos sem DP e com DP, em uso de dose superior. Já o EIEOA foi menor nos indivíduos em uso de doses ≤ 600 miligramas, quando comparado aos demais grupos. Conclusão Doses diárias de levodopa iguais ou inferiores a 600 mg/dia aumentam as respostas mecanotransdutoras cocleares nas frequências de 2 e 3 kHz, enquanto que a ação dos sistemas eferentes olivococleares é reduzida nesta região.

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Section: Discussionmentioning

confidence: 99%

Efeito da levodopa na mecânica coclear e no sistema auditivo eferente de indivíduos com doença de Parkinson

Lopes

Melo

Corona

et al. 2019

CoDAS

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“…At present it is unclear how MOC or LOC synapses change with age in humans or other strains of mice. Substantial reorganization of efferent synapses may serve to minimize excitotoxic damage to auditory nerve dendrites, which could prevent accumulated damage from everyday noise exposures (Nouvian et al, 2015). …”

Section: Discussionmentioning

confidence: 99%

Minimal Effects of Age and Exposure to a Noisy Environment on Hearing in Alpha9 Nicotinic Receptor Knockout Mice

Lauer

2017

Front. Neurosci.

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Studies have suggested a role of weakened medial olivocochlear (OC) efferent feedback in accelerated hearing loss and increased susceptibility to noise. The present study investigated the progression of hearing loss with age and exposure to a noisy environment in medial OC-deficient mice. Alpha9 nicotinic acetylcholine receptor knockout (α9KO) and wild types were screened for hearing loss using auditory brainstem responses. α9KO mice housed in a quiet environment did not show increased hearing loss compared to wild types in young adulthood and middle age. Challenging the medial OC system by housing in a noisy environment did not increase hearing loss in α9KO mice compared to wild types. ABR wave 1 amplitudes also did not show differences between α9KO mice and wild types. These data suggest that deficient medial OC feedback does not result in early onset of hearing loss.

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“…They may have continued functioning, for example, by their input on auditory afferents, or by transient innervation of IHC (cf. Nouvian et al, ). This does, however, not rule out any early short‐or long‐term disturbances elicited by noise.…”

Section: Discussionmentioning

confidence: 99%

“…It is believed that, under these conditions, afferent synaptic contacts are lost and that efferent neurons form (transient) synapses with IHC (cf. Nouvian et al, ).…”

Section: Discussionmentioning

confidence: 99%

Absence of Early Neuronal Death in the Olivocochlear System Following Acoustic Overstimulation

Reuss

Closhen

Riemann

et al. 2015

The Anatomical Record

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This study was conducted to examine possible effects of noise trauma on olivocochlear (OC) neurons. Anesthetized rats were exposed to a continuous 10 kHz pure tone at 120 dB sound pressure level for 2 hrs. The effects of treatment were verified by recordings of auditory brainstem response and distortion product otoacoustic emission. Three or 8 days after acoustic trauma, rats received unilateral injections of an aqueous solution of the retrograde neuronal tracer Fluorogold (FG) into the scala tympani to identify OC neurons (OCN). Five days after FG injection, brains were perfusion-fixed, and brainstem sections were cut and analyzed with respect to FG-labeled neurons. We found that, in both groups, numbers of OCN were similar to that of controls. The incubation of a second set of sections with antibodies against choline-acetyltransferase (the enzyme responsible for acetylcholine synthesis) showed the cholinergic neurons of the brainstem, however, without suggesting differences between groups. Our study, the first to investigate noise trauma effects on identified OCN, revealed that no visible alterations occurred in 2 weeks following trauma, neither in identified OCN nor in cholineacetyltransferase-immunofluorescence. At this time, auditory brainstem response and distortion product otoacoustic emission measurements showed severe signs of hearing loss. The mechanisms leading to hearing loss upon noise trauma apparently do not involve degeneration of OCN. Anat Rec, 299:103-110, 2016. V C 2015 Wiley Periodicals, Inc.Abbreviations used: ABR 5 auditory brainstem response; ChAT 5 choline-acetyltransferase; DPOAE 5 distortion product otoacoustic emission; FG 5 Fluorogold; IHC 5 inner hair cells; LOC/MOC 5 lateral/medial olivocochlear neurons; LSO 5 lateral superior olive; OC 5 olivocochlear; OCN 5 olivocochlear neurons; OHC 5 outer hair cells; PBS 5 phosphate-buffered 0.9% saline; RPO 5 rostral paraolivary region; RT 5 room temperature; SOC 5 superior olivary complex; SPL 5 sound pressure level; VNTB 5 ventral nucleus of the trapezoid body Grant sponsor: R€ ottger-Stiftung; Grant sponsor: HoffmannKlose-Stiftung.

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Cochlear efferents in developing adult and pathological conditions

Cited by 34 publications

References 79 publications

Efeito da levodopa na mecânica coclear e no sistema auditivo eferente de indivíduos com doença de Parkinson

Efeito da levodopa na mecânica coclear e no sistema auditivo eferente de indivíduos com doença de Parkinson

Minimal Effects of Age and Exposure to a Noisy Environment on Hearing in Alpha9 Nicotinic Receptor Knockout Mice

Absence of Early Neuronal Death in the Olivocochlear System Following Acoustic Overstimulation

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