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Start Over Descriptor "outer hair cells" Journal proceedings of the national academy of sciences of the united states of america
80 results on '"outer hair cells"'

1. Reticular lamina and basilar membrane vibrations in living mouse cochleae.

Author

Tianying Ren, Wenxuan He, and Kemp, David

Subjects
*MAMMAL hearing, *HAIR cells, *BASILAR membrane, *ACOUSTIC vibrations, *INTERFEROMETERS
Abstract

It is commonly believed that the exceptional sensitivity of mammalian hearing depends on outer hair cells which generate forces for amplifying sound-induced basilar membrane vibrations, yet how cellular forces amplify vibrations is poorly understood. In this study, by measuring subnanometer vibrations directly from the reticular lamina at the apical ends of outer hair cells and from the basilar membrane using a custom-built heterodyne low-coherence interferometer, we demonstrate in living mouse cochleae that the sound-induced reticular lamina vibration is substantially larger than the basilar membrane vibration not only at the best frequency but surprisingly also at low frequencies. The phase relation of reticular lamina to basilar membrane vibration changes with frequency by up to 180 degrees from ~135 degrees at low frequencies to ~-45 degrees at the best frequency. The magnitude and phase differences between reticular lamina and basilar membrane vibrations are absent in postmortem cochleae. These results indicate that outer hair cells do not amplify the basilar membrane vibration directly through a local feedback as commonly expected; instead, they actively vibrate the reticular lamina over a broad frequency range. The outer hair cell-driven reticular lamina vibration collaboratively interacts with the basilar membrane traveling wave primarily through the cochlear fluid, which boosts peak responses at the best-frequency location and consequently enhances hearing sensitivity and frequency selectivity. [ABSTRACT FROM AUTHOR]

Published
2016
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2. The α10 nicotinic acetyicholine receptor subunit is required for normal synaptic function and integrity of the olivocochlear system.

Author

Vetter, Douglas E., Katz, Eleonora, Maison, Stéphane F., Taranda, Julián, Turcan, Sevin, Ballestero±, Jimena, Liberman, M. Charles, Elgoyhen, A. Belén, and Boulter, Jim

Subjects
*CHOLINERGIC receptors, *ELECTROPHYSIOLOGY, *MICE, *HAIR cells, *SYNAPSES
Abstract

Although homomeric channels assembled from the α9 nicotinic acetylcholine receptor (nAChR) subunit are functional in vitro, electrophysiological, anatomical, and molecular data suggest that native cholinergic olivocochlear function is mediated via heteromeric nAChRs composed of both α9 and α10 subunits. To gain insight into α10 subunit function in vivo, we examined olivocochlear innervation and function in α10 null-mutant mice. Electrophysiological recordings from postnatal (P) days P8-9 inner hair cells revealed ACh-gated currents in α10+/+ and α10-/- mice, with no detectable responses to ACh in α10-/- mice. In contrast, a proportion of α10-/- outer hair cells showed small ACh-evoked currents. In α10-/- mutant mice, olivocochlear fiber stimulation failed to suppress distortion products, suggesting that the residual α9-/- homomeric nAChRs expressed by outer hair cells are unable to transduce efferent signals in vivo. Finally, α10-/- mice exhibit both an abnormal olivocochlear morphology and innervation to outer hair cells and a highly disorganized efferent innervation to the inner hair cell region. Our results demonstrate that α9-/- and α10-/- mice have overlapping but nonidentical phenotypes. Moreover, α10 nAChR subunits are required for normal olivocochlear activity because α9 homomeric nAChRs do not support maintenance of normal olivocochlear innervation or function in α10-/- mutant mice. [ABSTRACT FROM AUTHOR]

Published
2007
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3. Hair bundles teaming up to tune the mammalian cochlea

Author

Anthony J. Ricci and Rohit Prakash

Subjects
Mammals, Multidisciplinary, integumentary system, Tectorial membrane, Molecular Motor Proteins, Motility, Anatomy, Biology, Models, Biological, Cochlea, Mice, medicine.anatomical_structure, Hearing, Bundle, Physical Sciences, Biophysics, medicine, otorhinolaryngologic diseases, Animals, Inner ear, Hair cell, sense organs, Outer hair cells, Process (anatomy)
Abstract

The mammalian inner ear separates complex sounds into individual frequency and amplitude components with remarkable precision. The active process is a term coined to encompass the mechanisms involved in establishing both frequency selectivity and sensitivity of the living cochlea (1). The underlying molecular mechanisms that establish the active process are under debate and incorporate two distinct schools of thought. The first and more widely accepted is based on outer hair cell (OHC) somatic motility. The second theory hinges on active hair bundle motility. In this issue of PNAS, Dierkes et al. (2) create a biophysical model of outer hair cells where hair bundles are tethered to each other by the tectorial membrane, the overlying membrane in which OHC hair bundles are embedded. This association enhances both the frequency selectivity and the gain provided by the hair bundle active processes. This model is significant because it demonstrates a realistic mechanism by which hair bundle force generation can be used in tandem to make a significant contribution to the active process and because it provides a basis in which the disparate mechanisms of the active process might be unified. That is, although the model does not explicitly include outer hair cell motility or the resonant properties of the tectorial membrane, considering these additional variables in the framework presented may provide a means by which both measured frequency and sensitivity can be reproduced theoretically.

Published
2008

4. Cochlear Structure in the Dolphin, Lagenorhynchus obliquidens

Author

James G. McCormick, Jerry Palin, Ernest Glen Wever, and Sam H. Ridgway

Subjects
Cell splitting, education.field_of_study, Multidisciplinary, biology, Lagenorhynchus obliquidens, Population, Anatomy, Inner hair cells, biology.organism_classification, Biological Sciences: Physiology, Cochlear structure, otorhinolaryngologic diseases, sense organs, Outer hair cells, education
Abstract

The cochleas of five specimens of the Pacific white-sided dolphin, Lagenorhynchus obliquidens , that had been fixed by intravital perfusion, embedded in celloidin, and sectioned in a continuous series, were studied with particular attention to the numbers and distribution of hair cells and ganglion cells. The number of inner hair cells is estimated as 3272 and the number of outer hair cells is estimated as 12,899, for a total of 16,171 cells. The ganglion-cell population is estimated as 50,412 after correction for cell splitting in the sectioning process.

Published
1972

34. ATP-gated ion channels mediate adaptation to elevated sound levels

Author

Housley, Gary D., Morton-Jones, Rachel, Vlajkovic, Srdjan M., Telang, Ravindra S., Paramananthasivam, Vinthiya, Tadros, Sherif F., Wong, Ann Chi Yan, Froud, Kristina E., Cederholm, Jennie M. E., Sivakumaran, Yogeesan, Snguanwongchai, Peerawuth, Khakh, Baljit S., Cockayne, Debra A., Thorne, Peter R., and Ryan, Allen F.

Published
2013

50. ATP8B1 Is Essential for Maintaining Normal Hearing

Author

Stapelbroek, Janneke M., Peters, Theo A., van Beurden, Denis H. A., Curfs, Jo H. A. J., Joosten, Anneke, Beynon, Andy J., van Leeuwen, Bibian M., van der Velden, Lieke M., Bull, Laura, Elferink, Ronald P. Oude, van Zanten, Bert A., Klomp, Leo W. J., Houwen, Roderick H. J., and Seidman, Jonathan G.

Published
2009
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