Ionic Currents and Electromotility in Inner Ear Hair Cells From Humans

1998 ◽  
Vol 79 (4) ◽  
pp. 2235-2239 ◽  
Author(s):  
John S. Oghalai ◽  
Jeffrey R. Holt ◽  
Takashi Nakagawa ◽  
Thomas M. Jung ◽  
Newton J. Coker ◽  
...  
Keyword(s):  
Inner Ear ◽  
Hair Cells ◽  
Ionic Currents ◽  
Sensory Epithelium ◽  
Outer Hair Cells ◽  
Sensory Receptor ◽  
Surgical Removal ◽  
Type I ◽  
Vestibular Hair Cells ◽  
Sensory Receptor Cells

Oghalai, John S., Jeffrey R. Holt, Takashi Nakagawa, Thomas M. Jung, Newton J. Coker, Herman A. Jenkins, Ruth Anne Eatock, and William E. Brownell. Ionic currents and electromotility in inner ear hair cells from humans. J. Neurophysiol. 79: 2235–2239, 1998. The upright posture and rich vocalizations of primates place demands on their senses of balance and hearing that differ from those of other animals. There is a wealth of behavioral, psychophysical, and CNS measures characterizing these senses in primates, but no prior recordings from their inner ear sensory receptor cells. We harvested human hair cells from patients undergoing surgical removal of life-threatening brain stem tumors and measured their ionic currents and electromotile responses. The hair cells were either isolated or left in situ in their sensory epithelium and investigated using the tight-seal, whole cell technique. We recorded from both type I and type II vestibular hair cells under voltage clamp and found four voltage-dependent currents, each of which has been reported in hair cells of other animals. Cochlear outer hair cells demonstrated electromotility in response to voltage steps like that seen in rodent animal models. Our results reveal many qualitative similarities to hair cells obtained from other animals and justify continued investigations to explore quantitative differences that may be associated with normal or pathological human sensation.

Electrically Evoked Motile Responses of Mammalian Type I Vestibular Hair Cells

1992 ◽  
Vol 2 (3) ◽  
pp. 181-191
Author(s):  
Hans Peter Zenner ◽  
Günter Reuter ◽  
Shi Hong ◽  
Ulrike Zimmermann ◽  
Alfred H. Gitter
Keyword(s):  
Hair Cells ◽  
Sensory Modality ◽  
Outer Hair Cells ◽  
Type I ◽  
Image Subtraction ◽  
Low Frequencies ◽  
Vestibular Hair Cells ◽  
Mechanical Responses ◽  
Contrast Enhanced ◽  
Length Changes

Vestibular hair cells, type I and II, with membrane potentials around -64 mV were prepared from guinea pig ampullar cristae and maculae. In type I cells, current injection, application of voltage steps during membrane patch-clamping, or extracellular alternating current (ac) fields evoked fast length changes of 50 nm to 500 nm of the cell “neck”. Mechanical responses were determined by computerized video techniques with contrast-enhanced digital image subtraction (DIS) and interpeak pixel counts (IPPC) or by double photodiode measurements. These techniques allowed spatial resolutions of 300 nm, 120 nm, and 50 nm, respectively. In contrast to measurements of high-frequency movements of auditory outer hair cells (OHCs), the mechanical responses of type I VHCs were restricted to low frequencies below 85 Hz. In addition to recently reported slow motility of VHCs, the present results suggest that fast mechanical VHC responses could significantly influence macular and cupular mechanics. Isometric and isotonic variants are discussed. The observed frequency maxima gap between VHCs and OHCs is suggested to contribute to a clear separation of the auditory and the vestibular sensory modality.

Developing inner ear sensory neurons require TrkB and TrkC receptors for innervation of their peripheral targets

Development ◽  
1995 ◽  
Vol 121 (10) ◽  
pp. 3381-3391 ◽  
Author(s):  
T. Schimmang ◽  
L. Minichiello ◽  
E. Vazquez ◽  
I. San Jose ◽  
F. Giraldez ◽  
...  
Keyword(s):  
Inner Ear ◽  
Hair Cells ◽  
Catalytic Domain ◽  
Sensory System ◽  
Sensory Epithelium ◽  
Outer Hair Cells ◽  
Developmental Study ◽  
Inner Hair Cells ◽  
Vestibular Neurons ◽  
Cochlear Neurons

The trkB and trkC genes are expressed during the formation of the vestibular and auditory system. To elucidate the function of trkB and trkC during this process, we have analysed mice carrying a germline mutation in the tyrosine kinase catalytic domain of these genes. Neuroanatomical analysis of homozygous mutant mice revealed neuronal deficiencies in the vestibular and cochlear ganglia. In trkB (−/−) animals vestibular neurons and a subset of cochlear neurons responsible for the innervation of outer hair cells were drastically reduced. The peripheral targets of the respective neurons showed severe innervation defects. A comparative analysis of ganglia from trkC (−/−) mutants revealed a moderate reduction of vestibular neurons and a specific loss of cochlear neurons innervating inner hair cells. No nerve fibres were detected in the sensory epithelium containing inner hair cells. A developmental study of trkB (−/−) and trkC (−/−) mice showed that some vestibular and cochlear fibres initially reached their peripheral targets but failed to maintain innervation and degenerated. TrkB and TrkC receptors are therefore required for the survival of specific neuronal populations and the maintenance of target innervation in the peripheral sensory system of the inner ear.

scholarly journals Early appearance of key transcription factors influence the spatiotemporal development of the human inner ear

2019 ◽  
Vol 379 (3) ◽  
pp. 459-471 ◽  
Author(s):  
Lejo Johnson Chacko ◽  
Consolato Sergi ◽  
Theresa Eberharter ◽  
Jozsef Dudas ◽  
Helge Rask-Andersen ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Inner Ear ◽  
Hair Cells ◽  
Transforming Growth Factor ◽  
Expression Patterns ◽  
Organ Of Corti ◽  
Sensory Epithelium ◽  
Receptor Expression ◽  
Cell Phenotype ◽  
Type I

AbstractExpression patterns of transcription factors leucine-rich repeat-containing G protein-coupled receptor 5 (LGR5), transforming growth factor-β-activated kinase-1 (TAK1), SRY (sex-determining region Y)-box 2 (SOX2), and GATA binding protein 3 (GATA3) in the developing human fetal inner ear were studied between the gestation weeks 9 and 12. Further development of cochlear apex between gestational weeks 11 and 16 (GW11 and GW16) was examined using transmission electron microscopy. LGR5 was evident in the apical poles of the sensory epithelium of the cochlear duct and the vestibular end organs at GW11. Immunostaining was limited to hair cells of the organ of Corti by GW12. TAK1 was immune positive in inner hair cells of the organ of Corti by GW12 and colocalized with p75 neurotrophic receptor expression. Expression for SOX2 was confined primarily to the supporting cells of utricle at the earliest stage examined at GW9. Intense expression for GATA3 was presented in the cochlear sensory epithelium and spiral ganglia at GW9. Expression of GATA3 was present along the midline of both the utricle and saccule in the zone corresponding to the striolar reversal zone where the hair cell phenotype switches from type I to type II. The spatiotemporal gradient of the development of the organ of Corti was also evident with the apex of the cochlea forming by GW16. It seems that highly specific staining patterns of several transcriptions factors are critical in guiding the genesis of the inner ear over development. Our findings suggest that the spatiotemporal gradient in cochlear development extends at least until gestational week 16.

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 Conserved and Divergent Principles of Planar Polarity Revealed by Hair Cell Development and Function

2021 ◽  
Vol 15 ◽  
Author(s):  
Michael R. Deans
Keyword(s):  
Hair Cell ◽  
Inner Ear ◽  
Hair Cells ◽  
Model Organism ◽  
Vestibular Function ◽  
Sensory Receptor ◽  
Apical Surface ◽  
Planar Polarity ◽  
Vestibular Hair Cells ◽  
Sensory Epithelia

Planar polarity describes the organization and orientation of polarized cells or cellular structures within the plane of an epithelium. The sensory receptor hair cells of the vertebrate inner ear have been recognized as a preeminent vertebrate model system for studying planar polarity and its development. This is principally because planar polarity in the inner ear is structurally and molecularly apparent and therefore easy to visualize. Inner ear planar polarity is also functionally significant because hair cells are mechanosensors stimulated by sound or motion and planar polarity underlies the mechanosensory mechanism, thereby facilitating the auditory and vestibular functions of the ear. Structurally, hair cell planar polarity is evident in the organization of a polarized bundle of actin-based protrusions from the apical surface called stereocilia that is necessary for mechanosensation and when stereociliary bundle is disrupted auditory and vestibular behavioral deficits emerge. Hair cells are distributed between six sensory epithelia within the inner ear that have evolved unique patterns of planar polarity that facilitate auditory or vestibular function. Thus, specialized adaptations of planar polarity have occurred that distinguish auditory and vestibular hair cells and will be described throughout this review. There are also three levels of planar polarity organization that can be visualized within the vertebrate inner ear. These are the intrinsic polarity of individual hair cells, the planar cell polarity or coordinated orientation of cells within the epithelia, and planar bipolarity; an organization unique to a subset of vestibular hair cells in which the stereociliary bundles are oriented in opposite directions but remain aligned along a common polarity axis. The inner ear with its complement of auditory and vestibular sensory epithelia allows these levels, and the inter-relationships between them, to be studied using a single model organism. The purpose of this review is to introduce the functional significance of planar polarity in the auditory and vestibular systems and our contemporary understanding of the developmental mechanisms associated with organizing planar polarity at these three cellular levels.

scholarly journals Supporting cells remove and replace sensory receptor hair cells in a balance organ of adult mice

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Stephanie A Bucks ◽  
Brandon C Cox ◽  
Brittany A Vlosich ◽  
James P Manning ◽  
Tot B Nguyen ◽  
...  
Keyword(s):  
Hair Cells ◽  
Head Movements ◽  
Sensory Receptor ◽  
Type I ◽  
Type Ii ◽  
Supporting Cells ◽  
Definitive Evidence ◽  
Vestibular Hair Cells ◽  
Adult Mice ◽  
Vestibular Organs

Vestibular hair cells in the inner ear encode head movements and mediate the sense of balance. These cells undergo cell death and replacement (turnover) throughout life in non-mammalian vertebrates. However, there is no definitive evidence that this process occurs in mammals. We used fate-mapping and other methods to demonstrate that utricular type II vestibular hair cells undergo turnover in adult mice under normal conditions. We found that supporting cells phagocytose both type I and II hair cells. Plp1-CreERT2-expressing supporting cells replace type II hair cells. Type I hair cells are not restored by Plp1-CreERT2-expressing supporting cells or by Atoh1-CreERTM-expressing type II hair cells. Destruction of hair cells causes supporting cells to generate 6 times as many type II hair cells compared to normal conditions. These findings expand our understanding of sensorineural plasticity in adult vestibular organs and further elucidate the roles that supporting cells serve during homeostasis and after injury.

scholarly journals Immunohistochemical localization of vimentin in the gerbil inner ear.

1989 ◽  
Vol 37 (12) ◽  
pp. 1787-1797 ◽  
Author(s):  
B A Schulte ◽  
J C Adams
Keyword(s):  
Epithelial Cells ◽  
Inner Ear ◽  
Hair Cells ◽  
Stria Vascularis ◽  
Cell Types ◽  
Immunohistochemical Localization ◽  
Outer Hair Cells ◽  
Type I ◽  
Basal Cells

Cells containing immunoreactive vimentin-type intermediate filaments (IF) were identified in paraffin sections and whole-mount preparations of the gerbil inner ear. Most connective tissue cells showed positive immunostaining, although one unusual class of stromal cell lacked vimentin. Several different types of epithelial cells contained high levels of vimentin. In the cochlea, Deiters' cells, inner phalangeal cells, Boettcher's cells, some outer sulcus cells, and the intermediate cells of the stria vascularis showed strong immunoreactivity. Strial basal cells exhibited weaker and less consistent staining. Neither inner nor outer hair cells were stained. In the vestibular system, hair cells with a morphology and location more characteristic of type I than of type II cells showed strong immunostaining for vimentin. Supporting cells in vestibular neurosensory epithelium stained with less intensity. These results were surprising because epithelial cells in vivo only rarely express vimentin-type IF. Although the functional significance of vimentin remains to be established, its presence in some but not other highly specialized cell types provides an excellent marker for investigating the lineage and morphogenesis of the complex inner ear tissues.

Development of the Sensory Receptor Cells in the Utricular Macula

1978 ◽  
Vol 86 (2) ◽  
pp. ORL-297-ORL-304 ◽  
Author(s):  
Thomas R. Van De Water ◽  
Jan Wersäll ◽  
Matti Anniko ◽  
Hans Nordeman
Keyword(s):  
Ultrastructural Level ◽  
Sensory Epithelium ◽  
Sensory Cells ◽  
Sensory Receptor ◽  
Type I ◽  
Utricular Macula ◽  
Cuticular Plate ◽  
Plate Formation ◽  
Sensory Receptor Cells ◽  
Developmental Characteristics

Normal CBA mice were timed for the developmental stage by the vaginal plug technique. The day of copulatory plug observance was designated as gestation day one. The developmental characteristics of the utricular macula sensory epithelium is described on an ultrastructural level from the 15th to the 19th day of gestation (approximate day of birth). The following pertinent observations are reported: (1) the formation of stereocilia begins prior to the 15th day and continues to approximately the 18th day, (2) the formation of the stereocilia suggests a mechanism of gradual transformation of existing cell surface microvilli, (3) the onset of the genesis of stereocilia precedes neuronal contact and cuticular plate formation, (4) stereocilia rootlets are forming before cuticular plate formation, (5) utricular sensory hair cells have undergone significant ultrastructural differentiation prior to the development of synaptic contacts, and (6) nerve chalice formation of type I sensory cells begins on the 18th day and is still incomplete at birth.

scholarly journals Optimization of spectral-domain optical coherence tomography with a supercontinuum source for in vivo motion detection of low reflective outer hair cells in guinea pig cochleae

2021 ◽  
Author(s):  
Fumiaki Nin ◽  
Samuel Choi ◽  
Takeru Ota ◽  
Zhang Qi ◽  
Hiroshi Hibino
Keyword(s):  
Optical Coherence Tomography ◽  
High Resolution ◽  
Guinea Pig ◽  
Hair Cells ◽  
Sensory Epithelium ◽  
Outer Hair Cells ◽  
Acquisition Time ◽  
Total Acquisition Time ◽  
Sd Oct

AbstractSound evokes sub-nanoscale vibration within the sensory epithelium. The epithelium contains not only immotile cells but also contractile outer hair cells (OHCs) that actively shrink and elongate synchronously with the sound. However, the in vivo motion of OHCs has remained undetermined. The aim of this work is to perform high-resolution and -accuracy vibrometry in live guinea pigs with an SC-introduced spectral-domain optical coherence tomography system (SD-OCT). In this study, to reveal the effective contribution of SC source in the recording of the low reflective materials with the short total acquisition time, we compare the performances of the SC-introduced SD-OCT (SCSD-OCT) to that of the conventional SD-OCT. As inanimate comparison objects, we record a mirror, a piezo actuator, and glass windows. For the measurements in biological materials, we use in/ex vivo guinea pig cochleae. Our study achieved the optimization of a SD-OCT system for high-resolution in vivo vibrometry in the cochlear sensory epithelium, termed the organ of Corti, in mammalian cochlea. By introducing a supercontinuum (SC) light source and reducing the total acquisition time, we improve the axial resolution and overcome the difficulty in recording the low reflective material in the presence of biological noise. The high power of the SC source enables the system to achieve a spatial resolution of 1.72 ± 0.00 μm on a mirror and reducing the total acquisition time contributes to the high spatial accuracy of sub-nanoscale vibrometry. Our findings reveal the vibrations at the apical/basal region of OHCs and the extracellular matrix, basilar membrane.

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