X-Ray Irradiation of the Inner Ear of the Guinea PigAn Electron Microscopic Study of the Degenerating Outer Hair Cells of the Organ of Corti

1970 ◽  
Vol 69 (1-6) ◽  
pp. 61-76 ◽  
Author(s):  
F. Ø. Winther
Keyword(s):  
Inner Ear ◽  
Microscopic Study ◽  
Electron Microscopic Study ◽  
Hair Cells ◽  
Organ Of Corti ◽  
Outer Hair Cells ◽  
Electron Microscopic ◽  
X Ray

An X-ray diffraction and electron-microscopic study of the influence of gamma radiation on multilayer AlGaAs/InGaAs/GaAs heterostructures

2006 ◽  
Vol 40 (6) ◽  
pp. 687-690 ◽  
Author(s):  
A. V. Bobyl ◽  
A. A. Gutkin ◽  
P. N. Brunkov ◽  
I. A. Zamoryanskaya ◽  
M. A. Yagovkina ◽  
...  
Keyword(s):  
Gamma Radiation ◽  
Microscopic Study ◽  
Electron Microscopic Study ◽  
X Ray Diffraction ◽  
Electron Microscopic ◽  
X Ray

scholarly journals Oncomodulin Is Expressed Exclusively by Outer Hair Cells in the Organ of Corti

1998 ◽  
Vol 46 (1) ◽  
pp. 29-39 ◽  
Author(s):  
Nobuki Sakaguchi ◽  
Michael T. Henzl ◽  
Isolde Thalmann ◽  
Ruediger Thalmann ◽  
Bradley A. Schulte
Keyword(s):  
Hair Cells ◽  
Calcium Binding ◽  
Organ Of Corti ◽  
Ultrastructural Level ◽  
Outer Hair Cells ◽  
Regulatory Function ◽  
Electron Microscopic ◽  
Wide Range ◽  
Intracellular Organelles ◽  
Functional Relevance

Oncomodulin (OM) is a small, acidic calcium-binding protein first discovered in a rat hepatoma and later found in placental cytotrophoblasts, the pre-implantation embryo, and in a wide variety of neoplastic tissues. OM was considered to be exclusively an oncofetal protein until its recent detection in extracts of the adult guinea pig's organ of Corti. Here we report that light and electron microscopic immunostaining of gerbil, rat, and mouse inner ears with a monoclonal antibody against recombinant rat OM localizes the protein exclusively in cochlear outer hair cells (OHCs). At the ultrastructural level, high gold labeling density was seen overlying the nucleus, cytoplasm, and the cuticular plate of gerbil OHCs. Few, if any, gold particles were present over intracellular organelles and the stereocilia. Staining of a wide range of similarly processed gerbil organs failed to detect immunoreactive OM in any other adult tissues. The mammalian genome encodes one α- and one β-isoform of parvalbumin (PV). The widely distributed α PV exhibits a very high affinity for Ca2+ and is believed to serve as a Ca2+ buffer. By contrast, OM, the mammalian β PV, displays a highly attenuated affinity for Ca2+, consistent with a Ca2+-dependent regulatory function. The exclusive association of OM with cochlear OHCs in mature tissues is likely to have functional relevance. Teleological considerations favor its involvement in regulating some aspect of OHC electromotility. Although the fast electromotile response of OHCs does not require Ca2+, its gain and magnitude are modulated by efferent innervation. Therefore, OM may be involved in mediation of intracellular responses to cholinergic stimulation, which are known to be Ca2+ regulated.

scholarly journals Aquaporin-6 Expression in the Cochlear Sensory Epithelium Is Downregulated by Salicylates

2010 ◽  
Vol 2010 ◽  
pp. 1-8 ◽  
Author(s):  
Paola Perin ◽  
Simona Tritto ◽  
Laura Botta ◽  
Jacopo Maria Fontana ◽  
Giulia Gastaldi ◽  
...  
Keyword(s):  
Inner Ear ◽  
Expression Pattern ◽  
Hair Cells ◽  
Organ Of Corti ◽  
Sensory Epithelium ◽  
Outer Hair Cells ◽  
Rt Pcr ◽  
Supporting Cells ◽  
Sensory Epithelia ◽  
Mechanical Compliance

We characterize the expression pattern of aquaporin-6 in the mouse inner ear by RT-PCR and immunohistochemistry. Our data show that in the inner ear aquaporin-6 is expressed, in both vestibular and acoustic sensory epithelia, by the supporting cells directly contacting hair cells. In particular, in the Organ of Corti, expression was strongest in Deiters' cells, which provide both a mechanical link between outer hair cells (OHCs) and the Organ of Corti, and an entry point for ion recycle pathways. Since aquaporin-6 is permeable to both water and anions, these results suggest its possible involvement in regulating OHC motility, directly through modulation of water and chloride flow or by changing mechanical compliance in Deiters' cells. In further support of this role, treating mice with salicylates, which impair OHC electromotility, dramatically reduced aquaporin-6 expression in the inner ear epithelia but not in control tissues, suggesting a role for this protein in modulating OHCs' responses.

scholarly journals Static length changes of cochlear outer hair cells can tune low-frequency hearing

2017 ◽  
Author(s):  
Nikola Ciganović ◽  
Rebecca L. Warren ◽  
Batu Keçeli ◽  
Stefan Jacob ◽  
Anders Fridberger ◽  
...  
Keyword(s):  
Inner Ear ◽  
Hair Cells ◽  
Organ Of Corti ◽  
Outer Hair Cells ◽  
Frequency Selectivity ◽  
Apical Region ◽  
Low Frequencies ◽  
Inner Hair Cells ◽  
Length Changes ◽  
The Brain

AbstractThe cochlea not only transduces sound-induced vibration into neural spikes, it also amplifies weak sound to boost its detection. Actuators of this active process are sensory outer hair cells in the organ of Corti, whereas the inner hair cells transduce the resulting motion into electric signals that propagate via the auditory nerve to the brain. However, how the outer hair cells modulate the stimulus to the inner hair cells remains unclear. Here, we combine theoretical modeling and experimental measurements near the cochlear apex to study the way in which length changes of the outer hair cells deform the organ of Corti. We develop a geometry-based kinematic model of the apical organ of Corti that reproduces salient, yet counter-intuitive features of the organ’s motion. Our analysis further uncovers a mechanism by which a static length change of the outer hair cells can sensitively tune the signal transmitted to the sensory inner hair cells. When the outer hair cells are in an elongated state, stimulation of inner hair cells is largely inhibited, whereas outer hair cell contraction leads to a substantial enhancement of sound-evoked motion near the hair bundles. This novel mechanism for regulating the sensitivity of the hearing organ applies to the low frequencies that are most important for the perception of speech and music. We suggest that the proposed mechanism might underlie frequency discrimination at low auditory frequencies, as well as our ability to selectively attend auditory signals in noisy surroundings.Author summaryOuter hair cells are highly specialized force producers inside the inner ear: they can change length when stimulated electrically. However, how exactly this electromotile effect contributes to the astonishing sensitivity and frequency selectivity of the inner ear has remained unclear. Here we show for the first time that static length changes of outer hair cells can sensitively regulate how much of a sound signal is passed on to the inner hair cells that forward the signal to the brain. Our analysis holds for the apical region of the inner ear that is responsible for detecting the low frequencies that matter most in speech and music. This shows a mechanisms for how frequency-selectivity can be achieved at low frequencies. It also opens a path for the efferent neural system to regulate hearing sensitivity.

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