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

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 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

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.

scholarly journals Inner Ear and Muscle Developmental Defects in Smpx-Deficient Zebrafish Embryos

2021 ◽  
Vol 22 (12) ◽  
pp. 6497
Author(s):  
Anna Ghilardi ◽  
Alberto Diana ◽  
Renato Bacchetta ◽  
Nadia Santo ◽  
Miriam Ascagni ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Inner Ear ◽  
Hair Cells ◽  
Muscle Fibers ◽  
Underlying Mechanism ◽  
Loss Of Function ◽  
Zebrafish Model ◽  
Developmental Defects ◽  
Inner Ear Development ◽  
Syndromic Hearing Loss

The last decade has witnessed the identification of several families affected by hereditary non-syndromic hearing loss (NSHL) caused by mutations in the SMPX gene and the loss of function has been suggested as the underlying mechanism. In the attempt to confirm this hypothesis we generated an Smpx-deficient zebrafish model, pointing out its crucial role in proper inner ear development. Indeed, a marked decrease in the number of kinocilia together with structural alterations of the stereocilia and the kinocilium itself in the hair cells of the inner ear were observed. We also report the impairment of the mechanotransduction by the hair cells, making SMPX a potential key player in the construction of the machinery necessary for sound detection. This wealth of evidence provides the first possible explanation for hearing loss in SMPX-mutated patients. Additionally, we observed a clear muscular phenotype consisting of the defective organization and functioning of muscle fibers, strongly suggesting a potential role for the protein in the development of muscle fibers. This piece of evidence highlights the need for more in-depth analyses in search for possible correlations between SMPX mutations and muscular disorders in humans, thus potentially turning this non-syndromic hearing loss-associated gene into the genetic cause of dysfunctions characterized by more than one symptom, making SMPX a novel syndromic gene.

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