scholarly journals Expression and Localization of BDNF/TrkB System in the Zebrafish Inner Ear

2020 ◽  
Vol 21 (16) ◽  
pp. 5787
Author(s):  
Antonino Germanà ◽  
Maria Cristina Guerrera ◽  
Rosaria Laurà ◽  
Maria Levanti ◽  
Marialuisa Aragona ◽  
...  
Keyword(s):  
Inner Ear ◽  
Hair Cells ◽  
Sensory Cells ◽  
Acoustic System ◽  
Rt Pcr ◽  
Double Immunofluorescence ◽  
Specific Receptor ◽  
Cell Localization ◽  
Age Dependent ◽  
Crista Ampullaris

Brain-derived neurotrophic factor (BDNF), a member of the neurotrophin family, is involved in multiple and fundamental functions of the central and peripheral nervous systems including sensory organs. Despite recent advances in knowledge on the functional significance of BDNF and TrkB in the regulation of the acoustic system of mammals, the localization of BDNF/TrkB system in the inner ear of zebrafish during development, is not well known. Therefore, the goal of the present study is to analyze the age-dependent changes using RT-PCR, Western Blot and single and double immunofluorescence of the BDNF and its specific receptor in the zebrafish inner ear. The results showed the mRNA expression and the cell localization of BDNF and TrkB in the hair cells of the crista ampullaris and in the neuroepithelium of the utricle, saccule and macula lagena, analyzed at different ages. Our results demonstrate that the BDNF/TrkB system is present in the sensory cells of the inner ear, during whole life. Therefore, this system might play a key role in the development and maintenance of the hair cells in adults, suggesting that the zebrafish inner ear represents an interesting model to study the involvement of the neurotrophins in the biology of sensory cells

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 Localization of Neurotrophin Specific Trk Receptors in Mechanosensory Systems of Killifish (Nothobranchius guentheri)

2021 ◽  
Vol 22 (19) ◽  
pp. 10411
Author(s):  
Marialuisa Aragona ◽  
Caterina Porcino ◽  
Maria Cristina Guerrera ◽  
Giuseppe Montalbano ◽  
Maria Levanti ◽  
...  
Keyword(s):  
Inner Ear ◽  
Hair Cells ◽  
S100 Protein ◽  
Sensory Systems ◽  
Sensory Cells ◽  
Lateral Line System ◽  
Suitable Model ◽  
Trk Receptors ◽  
Line System ◽  
Nothobranchius Guentheri

Neurotrophins (NTs) and their signal-transducing Trk receptors play a crucial role in the development and maintenance of specific neuronal subpopulations in nervous and sensory systems. NTs are supposed to regulate two sensory systems in fish, the inner ear and the lateral line system (LLS). The latter is one of the major mechanosensory systems in fish. Considering that annual fishes of the genus Nothobranchius, with their short life expectancy, have become a suitable model for aging studies and that the occurrence and distribution of neurotrophin Trk receptors have never been investigated in the inner ear and LLS of killifish (Nothobranchius guentheri), our study aimed to investigate the localization of neurotrophin-specific Trk receptors in mechanosensory systems of N. guentheri. For histological and immunohistochemical analysis, adult specimens of N. guentheri were processed using antibodies against Trk receptors and S100 protein. An intense immunoreaction for TrkA and TrkC was found in the sensory cells of the inner ear as well as in the hair cells of LLS. Moreover, also the neurons localized in the acoustic ganglia displayed a specific immunoreaction for all Trk receptors (TrkA, B, and C) analyzed. Taken together, our results demonstrate, for the first time, that neurotrophins and their specific receptors could play a pivotal role in the biology of the sensory cells of the inner ear and LLS of N. guentheri and might also be involved in the hair cells regeneration process in normal and aged conditions.

scholarly journals Phase-locked spiking of inner ear hair cells and the driven noisy Adler equation

2014 ◽  
Vol 4 (6) ◽  
pp. 20140022 ◽  
Author(s):  
Roie Shlomovitz ◽  
Yuttana Roongthumskul ◽  
Seung Ji ◽  
Dolores Bozovic ◽  
Robijn Bruinsma
Keyword(s):  
Inner Ear ◽  
Hair Cells ◽  
Optimal Level ◽  
Sensory Cells ◽  
Experimental Measurements ◽  
Weak Signal ◽  
Sensitive Detector ◽  
Theoretical Predictions ◽  
External Signals

The inner ear constitutes a remarkably sensitive mechanical detector. This detection occurs in a noisy and highly viscous environment, as the sensory cells—the hair cells—are immersed in a fluid-filled compartment and operate at room or higher temperatures. We model the active motility of hair cell bundles of the vestibular system with the Adler equation, which describes the phase degree of freedom of bundle motion. We explore both analytically and numerically the response of the system to external signals, in the presence of white noise. The theoretical model predicts that hair bundles poised in the quiescent regime can exhibit sporadic spikes—sudden excursions in the position of the bundle. In this spiking regime, the system exhibits stochastic resonance, with the spiking rate peaking at an optimal level of noise. Upon the application of a very weak signal, the spikes occur at a preferential phase of the stimulus cycle. We compare the theoretical predictions of our model to experimental measurements obtained in vitro from individual hair cells. Finally, we show that an array of uncoupled hair cells could provide a sensitive detector that encodes the frequency of the applied signal.

scholarly journals Myosin I and adaptation of mechanical transduction by the inner ear

2004 ◽  
Vol 359 (1452) ◽  
pp. 1945-1951 ◽  
Author(s):  
K. C. Holmes ◽  
D. R. Trentham ◽  
R. Simmons ◽  
Peter G. Gillespie
Keyword(s):  
Hair Cell ◽  
Muscle Contraction ◽  
Inner Ear ◽  
Hair Cells ◽  
Sensory Cells ◽  
Detailed Understanding ◽  
Myosin I ◽  
Mechanical Transduction ◽  
Transduction Current

Twenty years ago, the description of hair-cell stereocilia as actin-rich structures led to speculation that myosin molecules participated in mechanical transduction in the inner ear. In 1987, Howard and Hudspeth proposed specifically that a myosin I might mediate adaptation of the transduction current carried by hair cells, the sensory cells of the ear. We exploited the myosin literature to design tests of this hypothesis and to show that the responsible isoform is myosin 1c. The identification of this myosin as the adaptation motor would have been impossible without thorough experimentation on other myosins, particularly muscle myosins. The sliding-filament hypothesis for muscle contraction has thus led to a detailed understanding of the behaviour of hair cells.

scholarly journals Barhl1 Regulatory Sequences Required for Cell-Specific Gene Expression and Autoregulation in the Inner Ear and Central Nervous System

2008 ◽  
Vol 28 (6) ◽  
pp. 1905-1914 ◽  
Author(s):  
Ramesh Chellappa ◽  
Shengguo Li ◽  
Sarah Pauley ◽  
Israt Jahan ◽  
Kangxin Jin ◽  
...  
Keyword(s):  
Gene Expression ◽  
Central Nervous System ◽  
Nervous System ◽  
Inner Ear ◽  
Hair Cells ◽  
Cerebellar Granule Cells ◽  
Sensory Cells ◽  
Specific Gene ◽  
Regulatory Sequences ◽  
Specific Gene Expression

ABSTRACT The development of the nervous system requires the concerted actions of multiple transcription factors, yet the molecular events leading to their expression remain poorly understood. Barhl1, a mammalian homeodomain transcription factor of the BarH class, is expressed by developing inner ear hair cells, cerebellar granule cells, precerebellar neurons, and collicular neurons. Targeted gene inactivation has demonstrated a crucial role for Barhl1 in the survival and/or migration of these sensory cells and neurons. Here we report the regulatory sequences of Barhl1 necessary for directing its proper spatiotemporal expression pattern in the inner ear and central nervous system (CNS). Using a transgenic approach, we have found that high-level and cell-specific expression of Barhl1 within the inner ear and CNS depends on both its 5′ promoter and 3′ enhancer sequences. Further transcriptional, binding, and mutational analyses of the 5′ promoter have identified two homeoprotein binding motifs that can be occupied and activated by Barhl1. Moreover, proper Barhl1 expression in inner ear hair cells and cerebellar and precerebellar neurons requires the presence of Atoh1. Together, these data delineate useful Barhl1 regulatory sequences that direct strong and specific gene expression to inner ear hair cells and CNS sensory neurons, establish a role for autoregulation in the maintenance of Barhl1 expression, and identify Atoh1 as a key upstream regulator.

scholarly journals Overactivation of Notch1 Signaling Induces Ectopic Hair Cells in the Mouse Inner Ear in an Age-Dependent Manner

PLoS ONE ◽  
2012 ◽  
Vol 7 (3) ◽  
pp. e34123 ◽  
Author(s):  
Zhiyong Liu ◽  
Thomas Owen ◽  
Jie Fang ◽  
Jian Zuo
Keyword(s):  
Inner Ear ◽  
Hair Cells ◽  
Dependent Manner ◽  
Notch1 Signaling ◽  
Age Dependent

scholarly journals Cells of adult brain germinal zone have properties akin to hair cells and can be used to replace inner ear sensory cells after damage

2008 ◽  
Vol 105 (52) ◽  
pp. 21000-21005 ◽  
Author(s):  
D. Wei ◽  
S. Levic ◽  
L. Nie ◽  
W.-q. Gao ◽  
C. Petit ◽  
...  
Keyword(s):  
Inner Ear ◽  
Hair Cells ◽  
Adult Brain ◽  
Sensory Cells ◽  
Germinal Zone

Morphometric analysis of the vestibular sensory epithelia of young adult rat

2003 ◽  
Vol 12 (4) ◽  
pp. 145-154
Author(s):  
R.J. Wubbels ◽  
H.A.A. de Jong ◽  
J. van Marle
Keyword(s):  
Cell Density ◽  
Hair Cells ◽  
The Elderly ◽  
Sensory Cells ◽  
Cross Sectional ◽  
Progressive Development ◽  
Adult Rat ◽  
Stage Of Development ◽  
Crista Ampullaris ◽  
Vestibular Sensory Epithelia

The appearance of vestibular sensory cells and their progressive development has been the subject of many ontogenetic studies. Because deteriorating hair cells are supposed to play a role in balance disorders of the elderly, the final stage of development (i.e. senescence) has been investigated as well. It is generally assumed that the number of hair cells in crista ampullaris, saccule and utricle slowly but steadily decreases with age. However, actual data covering the period between maturation and senescence are scarce. In the present study, rat vestibular epithelia were labeled for actin and tubulin. Morphology was inspected from immediately after weaning until the age of 12 months. Although, postnatal development was no part of this study some data on one day old epithelia are presented for comparison. At postnatal day 1, hair bundles are still shorter than in mature sensory organs, the width of the zonula adherens is less, and the apical cross-sectional area of the epithelial cells is smaller. After one month, maturation is complete. Total cell density is 400âĂŞ500 per 0.01 mm 2 , both in the otolith maculae and in the cristae ampullares. During the first year after maturation, no changes in epithelial morphology were observed and cell density remains constant.

Fluorocitrate Neural Dystrophy of the Guinea Pig Cochlea

1975 ◽  
Vol 33 ◽  
pp. 368-369
Author(s):  
G.J. Spector ◽  
C.D. Carr ◽  
I. Kaufman Arenberg ◽  
R.H. Maisel
Keyword(s):  
Hearing Loss ◽  
Hair Cells ◽  
Sodium Phosphate ◽  
Sensory Cells ◽  
Barium Salt ◽  
Perfusion Medium ◽  
Cochlear Hair Cells ◽  
Neural Degeneration ◽  
Sodium Phosphate Buffer ◽  
Cochlear Neurons

All studies on primary neural degeneration in the cochlea have evaluated the end stages of degeneration or the indiscriminate destruction of both sensory cells and cochlear neurons. We have developed a model which selectively simulates the dystrophic changes denoting cochlear neural degeneration while sparing the cochlear hair cells. Such a model can be used to define more precisely the mechanism of presbycusis or the hearing loss in aging man.Twenty-two pigmented guinea pigs (200-250 gm) were perfused by the perilymphatic route as live preparations using fluorocitrate in various concentrations (15-250 ug/cc) and at different incubation times (5-150 minutes). The barium salt of DL fluorocitrate, (C6H4O7F)2Ba3, was reacted with 1.0N sulfuric acid to precipitate the barium as a sulfate. The perfusion medium was prepared, just prior to use, as follows: sodium phosphate buffer 0.2M, pH 7.4 = 9cc; fluorocitrate = 15-200 mg/cc; and sucrose = 0.2M.

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