scholarly journals Distortion product emissions from a cochlear model with nonlinear mechanoelectrical transduction in outer hair cells

2010 ◽  
Vol 127 (4) ◽  
pp. 2420-2432 ◽  
Author(s):  
Yi-Wen Liu ◽  
Stephen T. Neely
Keyword(s):  
Hair Cells ◽  
Outer Hair Cells ◽  
Cochlear Model ◽  
Mechanoelectrical Transduction ◽  
Distortion Product

scholarly journals Distinct roles of stereociliary links in the nonlinear sound processing and noise resistance of cochlear outer hair cells

2020 ◽  
Vol 117 (20) ◽  
pp. 11109-11117
Author(s):  
Woongsu Han ◽  
Jeong-Oh Shin ◽  
Ji-Hyun Ma ◽  
Hyehyun Min ◽  
Jinsei Jung ◽  
...  
Keyword(s):  
Hair Cells ◽  
Otoacoustic Emissions ◽  
Essential Role ◽  
High Sensitivity ◽  
Outer Hair Cells ◽  
Tectorial Membrane ◽  
Sound Processing ◽  
Mechanoelectrical Transduction ◽  
Distortion Product ◽  
Membrane Attachment

Outer hair cells (OHCs) play an essential role in hearing by acting as a nonlinear amplifier which helps the cochlea detect sounds with high sensitivity and accuracy. This nonlinear sound processing generates distortion products, which can be measured as distortion-product otoacoustic emissions (DPOAEs). The OHC stereocilia that respond to sound vibrations are connected by three kinds of extracellular links: tip links that connect the taller stereocilia to shorter ones and convey force to the mechanoelectrical transduction channels, tectorial membrane-attachment crowns (TM-ACs) that connect the tallest stereocilia to one another and to the overlying TM, and horizontal top connectors (HTCs) that link adjacent stereocilia. While the tip links have been extensively studied, the roles that the other two types of links play in hearing are much less clear, largely because of a lack of suitable animal models. Here, while analyzing genetic combinations of tubby mice, we encountered models missing both HTCs and TM-ACs or HTCs alone. We found that the tubby mutation causes loss of both HTCs and TM-ACs due to a mislocalization of stereocilin, which results in OHC dysfunction leading to severe hearing loss. Intriguingly, the addition of the modifier allele modifier of tubby hearing 1 in tubby mice selectively rescues the TM-ACs but not the HTCs. Hearing is significantly rescued in these mice with robust DPOAE production, indicating an essential role of the TM-ACs but not the HTCs in normal OHC function. In contrast, the HTCs are required for the resistance of hearing to damage caused by noise stress.

Pengaruh sisplatin dosis tinggi terhadap penurunan fungsi sel rambut luar koklea

2013 ◽  
Vol 40 (2) ◽  
Author(s):  
Asti Kristianti ◽  
Teti Madiadipoera ◽  
Bogi Soeseno
Keyword(s):  
Hair Cells ◽  
Malignant Neoplasm ◽  
Otoacoustic Emission ◽  
Outer Hair Cells ◽  
High Dose ◽  
Distortion Product Otoacoustic Emission ◽  
Inclusion Criteria ◽  
Cochlear Hair Cells ◽  
Distortion Product ◽  
Bilateral Sensorineural Hearing Loss

Background: Chemotherapy is worldwide used nowadays, and its toxicity still remain a problemespecially toxicity to the ear (ototoxicity). Cisplatin (cis-diamminedichloroplatinum) is one of themost commonly used chemotherapy and highly potent in treating epithelial malignancies. Ototoxicitycaused by cisplatin is irreversible, progressive, bilateral, sensorineural hearing loss especially on highfrequency (4-8 KHz) accompanied by tinnitus. Purpose: To observe the cochlear outer hair cells damagein malignancies patients treated with cisplatin. Methods: This study is an observational analytic studywith prospective design to determine the influence of high dose cisplatin on cochlear outer hair cellsfunction. The research was carried out at the ENT-HNS Department, Hasan Sadikin General HospitalBandung, from November 2007 until June 2008. Audiometry, tympanometry, and distortion productotoacoustic emission (DPOAE) examinations were conducted before chemotherapy and DPOAE, andtimpanometry was again measured three days after first and second cycles of cisplatin administration. McNemar test was performed to calculate the effects of high-dose cisplatin to the cochlear outer haircells function. To compare pre and post-cisplatin on alteration of cochlear hair cells function, Wilcoxontest was used. Results: In this study 60 ears from 30 subjects that meet the inclusion criteria, consistedof 25 man (83.3%) and 5 women (16.7%). The prevalence of damaged cochlear outer hair cells were63% at first cycle and 70% at second cycle of cisplatin administration. The decline of cochlear outerhair cells function was significant (p<0.001). Conclusion: High-dose cisplatin decreases cochlear outerhair cells function in patients with malignant neoplasm. Abstrak : Latar belakang: Kemoterapi sekarang rutin digunakan secara klinis di seluruh dunia. Sejalan denganhal tersebut toksisitas kemoterapi, khususnya terhadap telinga saat ini menjadi perhatian. Sisplatin(cis-diamminedichloroplatinum) adalah salah satu obat kemoterapi yang paling banyak digunakandan paling manjur untuk terapi keganasan epitelial. Efek ototoksik sisplatin yaitu terjadi gangguandengar sensorineural yang irreversible, progresif, bilateral pada frekuensi tinggi (4-8 kHz), dan disertaidengan tinitus. Tujuan: Untuk menilai penurunan fungsi sel rambut luar koklea pada penderita tumorganas sesudah pemberian sisplatin dosis tinggi dengan menggunakan DPOAE. Metode: Studi analitikobservasional dengan rancangan prospektif di Bagian IK. THT-KL RS. Hasan Sadikin Bandung mulaibulan November 2007 sampai dengan Juni 2008. Pada penelitian ini dilakukan pemeriksaan audiometrinada murni, timpanometri, dan distortion product otoacoustic emission (DPOAE) prakemoterapi, kemudianDPOAE dan timpanometri diulang tiga hari sesudah siklus pertama dan kedua kemoterapi sisplatin. Datayang diperoleh diuji dengan uji McNemar dan uji Wilcoxon. Hasil: Dari penelitian didapat 60 telingadari 30 subjek penelitian yang memenuhi kriteria inklusi yang terdiri dari 25 laki-laki (83,3%) dan 5perempuan (16,7%). Insidens penurunan fungsi sel rambut luar koklea sebesar 63% (38 kasus) sesudahsiklus pertama dan 70% (42 kasus) sesudah siklus kedua. Hubungan penurunan fungsi sel rambut luarkoklea memberikan nilai yang sangat bermakna sejak pemberian siklus pertama (p<0,001). Kesimpulan:Pemberian sisplatin dosis tinggi pada penderita tumor ganas menyebabkan penurunan fungsi sel rambutluar koklea.Kata kunci: kemoterapi, sisplatin dosis tinggi, sel rambut luar koklea.

scholarly journals A Tmc1 mutation reduces calcium permeability and expression of mechanoelectrical transduction channels in cochlear hair cells

2019 ◽  
Vol 116 (41) ◽  
pp. 20743-20749 ◽  
Author(s):  
Maryline Beurg ◽  
Amanda Barlow ◽  
David N. Furness ◽  
Robert Fettiplace
Keyword(s):  
Hair Cells ◽  
Single Channel ◽  
Maximum Amplitude ◽  
Outer Hair Cells ◽  
Single Amino Acid ◽  
Wild Type ◽  
Cochlear Hair Cells ◽  
Proximate Cause ◽  
Mechanoelectrical Transduction ◽  
Calcium Permeability

Mechanoelectrical transducer (MET) currents were recorded from cochlear hair cells in mice with mutations of transmembrane channel-like protein TMC1 to study the effects on MET channel properties. We characterized a Tmc1 mouse with a single-amino-acid mutation (D569N), homologous to a dominant human deafness mutation. Measurements were made in both Tmc2 wild-type and Tmc2 knockout mice. By 30 d, Tmc1 pD569N heterozygote mice were profoundly deaf, and there was substantial loss of outer hair cells (OHCs). MET current in OHCs of Tmc1 pD569N mutants developed over the first neonatal week to attain a maximum amplitude one-third the size of that in Tmc1 wild-type mice, similar at apex and base, and lacking the tonotopic size gradient seen in wild type. The MET-channel Ca2+ permeability was reduced 3-fold in Tmc1 pD569N homozygotes, intermediate deficits being seen in heterozygotes. Reduced Ca2+ permeability resembled that of the Tmc1 pM412K Beethoven mutant, a previously studied semidominant mouse mutation. The MET channel unitary conductance, assayed by single-channel recordings and by measurements of current noise, was unaffected in mutant apical OHCs. We show that, in contrast to the Tmc1 M412K mutant, there was reduced expression of the TMC1 D569N channel at the transduction site assessed by immunolabeling, despite the persistence of tip links. The reduction in MET channel Ca2+ permeability seen in both mutants may be the proximate cause of hair-cell apoptosis, but changes in bundle shape and protein expression in Tmc1 D569N suggest another role for TMC1 apart from forming the channel.

Mechanoelectrical transduction of adult outer hair cells studied in a gerbil hemicochlea

Nature ◽  
2004 ◽  
Vol 429 (6993) ◽  
pp. 766-770 ◽  
Author(s):  
David Z. Z. He ◽  
Shuping Jia ◽  
Peter Dallos
Keyword(s):  
Hair Cells ◽  
Outer Hair Cells ◽  
Mechanoelectrical Transduction

A multi-compartment cochlear model with piezo-electric outer hair cells: Methods and results

2006 ◽  
Vol 39 ◽  
pp. S434
Author(s):  
A. Hubbard ◽  
J. Spisak ◽  
S. Lu ◽  
D. Mountain
Keyword(s):  
Hair Cells ◽  
Outer Hair Cells ◽  
Cochlear Model ◽  
Piezo Electric

scholarly journals Amplification lags nonlinearity in the recovery from reduced endocochlear potential

2020 ◽  
Author(s):  
C. Elliott Strimbu ◽  
Yi Wang ◽  
Elizabeth S. Olson
Keyword(s):  
Hair Cells ◽  
Otoacoustic Emissions ◽  
Basilar Membrane ◽  
Frequency Tuning ◽  
Organ Of Corti ◽  
Endocochlear Potential ◽  
Outer Hair Cells ◽  
Frequency Resolution ◽  
Operating Condition ◽  
Distortion Product

ABSTRACTThe mammalian hearing organ, the cochlea, contains an active amplifier to boost the vibrational response to low level sounds. Hallmarks of this active process are sharp location-dependent frequency tuning and compressive nonlinearity over a wide stimulus range. The amplifier relies on outer hair cell (OHC) generated forces driven in part by the endocochlear potential (EP), the ~ +80 mV potential maintained in scala media, generated by the stria vascularis. We transiently eliminated the EP in vivo by an intravenous injection of furosemide and measured the vibrations of different layers in the cochlea’s organ of Corti using optical coherence tomography. Distortion product otoacoustic emissions (DPOAE) were monitored at the same times. Following the injection, the vibrations of the basilar membrane lost the best frequency (BF) peak and showed broad tuning similar to a passive cochlea. The intra-organ of Corti vibrations measured in the region of the OHCs lost their BF peak and showed low-pass responses, but retained nonlinearity, indicating that OHC electromotility was still operational. Thus, while electromotility is presumably necessary for amplification, its presence is not sufficient for amplification. The BF peak recovered nearly fully within 2 hours, along with a non-monotonic DPOAE recovery that suggests that physical shifts in operating condition are a final step in the recovery process.SIGNIFICANCEThe endocochlear potential, the +80 mV potential difference across the fluid filled compartments of the cochlea, is essential for normal mechanoelectrical transduction, which leads to receptor potentials in the sensory hair cells when they vibrate in response to sound. Intracochlear vibrations are boosted tremendously by an active nonlinear feedback process that endows the cochlea with its healthy sensitivity and frequency resolution. When the endocochlear potential was reduced by an injection of furosemide, the basilar membrane vibrations resembled those of a passive cochlea, with broad tuning and linear scaling. The vibrations in the region of the outer hair cells also lost the tuned peak, but retained nonlinearity at frequencies below the peak, and these sub-BF responses recovered fairly rapidly. Vibration responses at the peak recovered nearly fully over 2 hours. The staged vibration recovery and a similarly staged DPOAE recovery suggests that physical shifts in operating condition are a final step in the process of cochlear recovery.

Functional effects of a monoclonal antibody on mechanoelectrical transduction in outer hair cells

2002 ◽  
Vol 164 (1-2) ◽  
pp. 190-205 ◽  
Author(s):  
Claudia C. Schulte ◽  
Jens Meyer ◽  
David N. Furness ◽  
Carole M. Hackney ◽  
Thomas R. Kleyman ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Hair Cells ◽  
Outer Hair Cells ◽  
Mechanoelectrical Transduction
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