Neuron-specific enolase-like immunoreactivity in inner hair cells but not outer hair cells in the guinea pig organ of Corti

1985 ◽  
Vol 327 (1-2) ◽  
pp. 379-384 ◽  
Author(s):  
R.A. Altschuler ◽  
K.A. Reeks ◽  
P.J. Marangos ◽  
J. Fex
Keyword(s):  
Guinea Pig ◽  
Hair Cells ◽  
Neuron Specific Enolase ◽  
Organ Of Corti ◽  
Outer Hair Cells ◽  
Inner Hair Cells

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.

Ultrastructural Cochlear Changes following Acoustic Hyperstimulation and Ototoxicity

1976 ◽  
Vol 85 (6) ◽  
pp. 740-751 ◽  
Author(s):  
David J. Lim
Keyword(s):  
Hair Cells ◽  
Sensory Cell ◽  
Ganglion Cells ◽  
Organ Of Corti ◽  
Acoustic Trauma ◽  
Nerve Fibers ◽  
Outer Hair Cells ◽  
Type I ◽  
Cell Degeneration ◽  
Inner Hair Cells

Using guinea pigs and chinchillas as experimental animals, modes and patterns of sensory cell damage by acoustic hyperstimulation and kanamycin intoxication were compared. In general, outer hair cells were more vulnerable to both acoustic trauma and ototoxicity (particularly in the basal turn) than inner hair cells. However, in kanamycin ototoxicity, the inner hair cells were more vulnerable in the apical coil. Nerve endings and nerve fibers generally were resistant to both acoustic trauma and kanamycin intoxication, and their degeneration appears to be secondary to the sensory cell degeneration. A large number of unmyelinated nerve fibers were seen in both the organ of Corti and the osseous spiral lamina even three months after the organ of Corti had been completely degenerated by ototoxicity. The total number of unmyelinated and myelinated nerve fibers in the osseous spiral lamina far exceeded the scanty surviving ganglion cells in Rosenthal's canal, indicating the possibility of regeneration of these fibers following kanamycin intoxication. The remaining few ganglion cells were mainly type II or type III cells, and a majority of the type I ganglion cells appeared to be degenerated. Signs of strial damage were observed in both acoustic trauma and ototoxicity, but their pattern did not correlate well with that of sensory cell degeneration.

The developing organ of Corti contains retinoic acid and forms supernumerary hair cells in response to exogenous retinoic acid in culture

Development ◽  
1993 ◽  
Vol 119 (4) ◽  
pp. 1041-1053 ◽  
Author(s):  
M.W. Kelley ◽  
X.M. Xu ◽  
M.A. Wagner ◽  
M.E. Warchol ◽  
J.T. Corwin
Keyword(s):  
Retinoic Acid ◽  
Hair Cells ◽  
Organ Of Corti ◽  
Sensory Epithelium ◽  
Outer Hair Cells ◽  
Supporting Cells ◽  
Embryonic Mouse ◽  
Inner Hair Cells ◽  
Sensory Epithelia

The mammalian organ of Corti has one of the most highly ordered patterns of cells in any vertebrate sensory epithelium. A single row of inner hair cells and three or four rows of outer hair cells extend along its length. The factors that regulate the formation of this strict pattern are unknown. In order to determine whether retinoic acid plays a role during the development of the organ of Corti, exogenous retinoic acid was added to embryonic mouse cochleae in vitro. Exogenous retinoic acid significantly increased the number of cells that developed as hair cells and resulted in large regions of supernumerary hair cells and supporting cells containing two rows of inner hair cells and up to 11 rows of outer hair cells. The effects of retinoic acid were dependent on concentration and on the timing of its addition. Western blot analysis indicated that cellular retinoic acid binding protein (CRABP) was present in the sensory epithelium of the embryonic cochlea. The amount of CRABP apparently increased between embryonic day 14 and postnatal day 1, but CRABP was not detectable in sensory epithelia from adults. A retinoic acid reporter cell line was used to demonstrate that retinoic acid was also present in the developing organ of Corti between embryonic day 14 and postnatal day 1, and was also present in adult cochleae at least in the vicinity of the modiolus. These results suggest that retinoic acid is involved in the normal development of the organ of Corti and that the effect of retinoic acid may be to induce a population of prosensory cells to become competent to differentiate as hair cells and supporting cells.

Dissociation between the calcium-induced and voltage-driven motility in cochlear outer hair cells from the waltzing guinea pig

1993 ◽  
Vol 104 (4) ◽  
pp. 1137-1143
Author(s):  
B. Canlon ◽  
D. Dulon
Keyword(s):  
Guinea Pig ◽  
Hair Cells ◽  
Guinea Pigs ◽  
Outer Hair Cell ◽  
Calcium Ionophore ◽  
Organ Of Corti ◽  
Length Change ◽  
Outer Hair Cells ◽  
Permeabilized Cells ◽  
Length Changes

The waltzing guinea pig, possessing an hereditary progressive deafness, shows pathology to the actin-bearing structures within the hair cells of the organ of Corti. In particular, the affected structures include the stereocilia, the cuticular plate and, as shown in the present study, swollen and disorganized subsurface cisternae. To test whether this pathology affected outer hair cell motility, cells were isolated from waltzing guinea pigs and their age-matched controls and were subjected to either electrical or chemical stimulation. Visual detection thresholds and the magnitude of the electrically-induced length changes were equivalent for both groups. However, when intracellular calcium was increased with either the calcium ionophore, ionomycin or Ca2+/ATP (under permeabilized conditions with DMSO), length changes were significantly reduced for the outer hair cells from waltzing guinea pigs compared to the controls. The average percent length increase induced by 10 microM ionomycin for the outer hair cells from control animals was 2.3 +/- 1.7 whereas for postnatal day 4 waltzing guinea pigs it was 1.3 +/- 1.7. Postnatal day 7 and 10 waltzing guinea pigs responded with significantly smaller percent length changes. The intracellular concentration of ionic calcium increased similarly for both groups after the application of ionomycin as revealed with the indicator fluo-3. In the permeabilized cells in the presence of Ca2+/ATP, control cells responded with a percent length change of 3.5, whereas, age-matched waltzing outer hair cells responded with barely detectable length changes.(ABSTRACT TRUNCATED AT 250 WORDS)

Blebs in inner and outer hair cells: a pathophysiological hypothesis

2008 ◽  
Vol 122 (11) ◽  
pp. 1151-1155 ◽  
Author(s):  
R Ramírez-Camacho ◽  
J R García-Berrocal ◽  
A Trinidad ◽  
J M Verdaguer ◽  
J Nevado
Keyword(s):  
Hair Cells ◽  
Outer Hair Cell ◽  
Ganglion Cells ◽  
Stria Vascularis ◽  
Spiral Ganglion ◽  
Organ Of Corti ◽  
Outer Hair Cells ◽  
Inner Hair Cells ◽  
Hearing Thresholds

AbstractIntroduction:The ototoxic effects of cisplatin include loss of outer hair cells, degeneration of the stria vascularis and a decrease in the number of spiral ganglion cells. Scanning microscopy has shown balloon-like protrusions (blebs) of the plasma membrane of inner hair cells following cisplatin administration. The present study was undertaken to identify the possible role of inner and outer hair cell blebs in the pathogenesis of cisplatin-induced ototoxicity.Materials and methods:Twenty-five guinea pigs were injected with cisplatin and their hearing tested at different time-points, before sacrifice and examination with scanning electron microscopy.Results and analysis:Seven animals showed blebs in the inner hair cells at different stages. Hearing thresholds were lower in animals showing blebs.Discussion:Cisplatin seems to be able to induce changes in inner hair cells as well as in other structures in the organ of Corti. Blebbing observed in animals following cisplatin administration could play a specific role in the regulation of intracellular pressure.

Localization of the P2Y4 Receptor in the Guinea Pig Organ of Corti

2003 ◽  
Vol 14 (06) ◽  
pp. 286-295
Author(s):  
Margarett S. Parker ◽  
Nkeiruka N. Onyenekwu ◽  
Richard P. Bobbin
Keyword(s):  
Guinea Pig ◽  
Hair Cells ◽  
Staining Pattern ◽  
Organ Of Corti ◽  
Staining Intensity ◽  
Protein Band ◽  
Outer Hair Cells ◽  
Metabotropic Receptor ◽  
Single Protein ◽  
P2y4 Receptor

Cochleae of guinea pigs were evaluated for the presence of the metabotropic receptor, P2Y4. Evidence is presented that P2Y4 protein is expressed in the guinea pig cochleae using Western blot analysis. A single protein band of 35 kDa was detected with P2Y4 receptor-specific antibody. The cellular distribution of P2Y4 purinoceptor protein was determined by immunohistochemistry of the whole organ of Corti. Immunoreactive staining for P2Y4 was seen in most cells of the organ of Corti. Staining of Hensen's cells and Deiters' cells, especially the outer Deiters' cells, was more intense than staining of the outer hair cells, inner hair cells, and pillar cells. Staining intensity was greatest at the basal turn and progressively decreased in the upper turns with the apex showing the weakest staining pattern. This is the first demonstration of a metabotropic P2Y receptor in the guinea pig organ of Corti.

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