scholarly journals Creatine kinase in epithelium of the inner ear.

1992 ◽  
Vol 40 (2) ◽  
pp. 185-192 ◽  
Author(s):  
S S Spicer ◽  
B A Schulte
Keyword(s):  
Creatine Kinase ◽  
Inner Ear ◽  
Vestibular System ◽  
Hair Cells ◽  
Stria Vascularis ◽  
Photoreceptor Cells ◽  
Cell Types ◽  
Dark Cells ◽  
Transitional Cells ◽  
Marginal Cells

Epithelium of the inner ear in the gerbil and mouse was examined immunocytochemically for presence of creatine kinase (CK). Marginal cells of the cochlear stria vascularis and dark cells and transitional cells of the vestibular system were found to contain an abundance of the MM isozyme (MM-CK). CK in these cells concurs with that which is coupled to Na,K-ATPase in other cells and is considered to supply ATP for the Na,K-ATPase that mediates the high KCl of endolymph. Inner hair cells revealed content of the BB isozyme and in this respect resembled the energy-transducing photoreceptor cells in retina. In addition, outer phalangeal (Deiters') cells stained for both MM- and BB-CK whereas inner phalangeal cells evidenced content of only the BB isozyme. Immunolocalization of CK appeared similar in mouse and gerbil inner ear. Specificity of the staining was affirmed by observations in agreement with those reported for CK in various cell types and by staining with antisera from more than one source.

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.

Distribution of glycoconjugates in ion transport cells of gerbil inner ear.

1991 ◽  
Vol 39 (4) ◽  
pp. 425-434 ◽  
Author(s):  
S Sugiyama ◽  
S S Spicer ◽  
P D Munyer ◽  
B A Schulte
Keyword(s):  
Epithelial Cells ◽  
Ion Transport ◽  
Inner Ear ◽  
Vestibular System ◽  
Lectin Binding ◽  
Spiral Ligament ◽  
Strong Staining ◽  
Transitional Cells ◽  
Marginal Cells ◽  
The One

Ion transport cells in gerbil inner ear were differentiated histochemically by staining glycoconjugates (GCs) with a battery of horseradish peroxidase-conjugated lectins. Strong staining with PSA and LCA showed a high content of N-linked oligosaccharides in transport cell GCs. Reactivity with PHA-L and PHA-E identified GC with triantennary and with bisected biantennary N-linked oligosaccharides, respectively, in these cells. High affinity for DSA and PWM demonstrated abundant N-acetyl lactosamine in N-linked side chains. Ion transporting epithelial cells reacting with lectins specific for N-linked oligosaccharides included strial marginal cells and outer sulcus cells of the cochlea and dark cells, transitional cells, and planum semilunatum cells of the vestibular system. In general, all of the inner ear transport epithelial cells revealed a similar lectin binding profile, with the one exception that SBA reacted strongly with ion transporting cells in the vestibular system but only weakly with those in the cochlea. Fibrocytes specialized for ion transport located in distinct areas in the suprastrial and inferior regions of the spiral ligament also stained with lectins that demonstrate N-glycosylation. However, transport fibrocytes differed from transport epithelial cells in two ways. First, they reacted e with HPA, DBA, VVA, and SJA specific for O-linkages and second, they failed to react with UEA I. The staining pattern for N-glycosylated GC resembled that for Na+, K(+)-ATPase in inner ear, suggesting a relationship between these constituents.

scholarly journals Evolution of Endolymph Secretion and Endolymphatic Potential Generation in the Vertebrate Inner Ear

2018 ◽  
Vol 92 (1-2) ◽  
pp. 1-31 ◽  
Author(s):  
Christine Köppl ◽  
Viviane Wilms ◽  
Ian John Russell ◽  
Hans Gerd Nothwang
Keyword(s):  
Inner Ear ◽  
Lateral Line ◽  
Vestibular System ◽  
Molecular Mechanisms ◽  
Receptor Potential ◽  
Cell Types ◽  
Cell Receptor ◽  
Striking Difference ◽  
High K ◽  
Endolymphatic Potential

The ear of extant vertebrates reflects multiple independent evolutionary trajectories. Examples include the middle ear or the unique specializations of the mammalian cochlea. Another striking difference between vertebrate inner ears concerns the differences in the magnitude of the endolymphatic potential. This differs both between the vestibular and auditory part of the inner ear as well as between the auditory periphery in different vertebrates. Here we provide a comparison of the cellular and molecular mechanisms in different endorgans across vertebrates. We begin with the lateral line and vestibular systems, as they likely represent plesiomorphic conditions, then review the situation in different vertebrate auditory endorgans. All three systems harbor hair cells bathed in a high (K+) environment. Superficial lateral line neuromasts are bathed in an electrogenically maintained high (K+) microenvironment provided by the complex gelatinous cupula. This is associated with a positive endocupular potential. Whether this is a special or a universal feature of lateral line and possibly vestibular cupulae remains to be discovered. The vestibular system represents a closed system with an endolymph that is characterized by an enhanced (K+) relative to the perilymph. Yet only in land vertebrates does (K+) exceed (Na+). The endolymphatic potential ranges from +1 to +11 mV, albeit we note intriguing reports of substantially higher potentials of up to +70 mV in the cupula of ampullae of the semicircular canals. Similarly, in the auditory system, a high (K+) is observed. However, in contrast to the vestibular system, the positive endolymphatic potential varies more substantially between vertebrates, ranging from near zero mV to approximately +100 mV. The tissues generating endolymph in the inner ear show considerable differences in cell types and location. So-called dark cells and the possibly homologous ionocytes in fish appear to be the common elements, but there is always at least one additional cell type present. To inspire research in this field, we propose a classification for these cell types and discuss potential evolutionary relationships. Their molecular repertoire is largely unknown and provides further fertile ground for future investigation. Finally, we propose that the ultimate selective pressure for an increased endolymphatic potential, as observed in mammals and to a lesser extent in birds, is specifically to maintain the AC component of the hair-cell receptor potential at high frequencies. In summary, we identify intriguing questions for future directions of research into the molecular and cellular basis of the endolymph in the different compartments of the inner ear. The answers will provide important insights into evolutionary and developmental processes in a sensory organ essential to many species, including humans.

Specialized Epithelia in the Avian Labyrinth (Its Distribution and Ultrastructure)

1971 ◽  
Vol 29 ◽  
pp. 404-405
Author(s):  
E. Ishiyama ◽  
J. Weibel ◽  
E. N. Myers
Keyword(s):  
Electron Microscopy ◽  
Inner Ear ◽  
Fluid Transport ◽  
Stria Vascularis ◽  
Dark Cells ◽  
Ultrastructural Characteristics ◽  
Tegmentum Vasculosum ◽  
Light Cells

In recently years the distribution of the non-sensory specialized epithella in the inner ear has been interested among otologists. Increased understanding of the problem dealing with the fluid transport within the endolymph has been obtained these studied. To our knowledge, however, the distribution of the avian specialized cells in the inner ear has not been described adequately. In addition, ultrastructural characteristics of the osmiophilic(dark) cells in the avian labyrinth were not clearly demonstrated. Therefore, the specialized epithlia in the avian labyrinth should be further investigated and the nature of their function defined.To demonstrat this, pigeois were investigated using phase and electron-microscopy. The specialized cells(dark and light cells) were distributed in the crlstae ampullaris, the tegmentum vasculosum of the lagena which is analogous to the stria vascularis in mammals, the saccule, the otolith lagena, the utricle and the crista negletica.

Cell fate choices and the expression of Notch, Delta and Serrate homologues in the chick inner ear: parallels with Drosophila sense-organ development

Development ◽  
1998 ◽  
Vol 125 (23) ◽  
pp. 4645-4654 ◽  
Author(s):  
J. Adam ◽  
A. Myat ◽  
I. Le Roux ◽  
M. Eddison ◽  
D. Henrique ◽  
...  
Keyword(s):  
Inner Ear ◽  
Cell Fate ◽  
Hair Cells ◽  
Early Stage ◽  
Sense Organ ◽  
Cell Types ◽  
Developmental Pathways ◽  
Supporting Cells ◽  
Notch Ligand ◽  
Developmental Program

The sensory patches in the vertebrate inner ear are similar in function to the mechanosensory bristles of a fly, and consist of a similar set of cell types. If they are truly homologous structures, they should also develop by similar mechanisms. We examine the genesis of the neurons, hair cells and supporting cells that form the sensory patches in the inner ear of the chick. These all arise from the otic epithelium, and are produced normally even in otic epithelium cultured in isolation, confirming that their production is governed by mechanisms intrinsic to the epithelium. First, the neuronal sublineage becomes separate from the epithelial: between E2 and E3.5, neuroblasts delaminate from the otocyst. The neuroblasts then give rise to a mixture of neurons and neuroblasts, while the sensory epithelial cells diversify to form a mixture of hair cells and supporting cells. The epithelial patches where this occurs are marked from an early stage by uniform and maintained expression of the Notch ligand Serrate1. The Notch ligand Delta1 is also expressed, but transiently and in scattered cells: it is seen both early, during neuroblast segregation, where it appears to be in the nascent neuroblasts, and again later, in the ganglion and in differentiating sensory patches, where it appears to be in the nascent hair cells, disappearing as they mature. Delta-Notch-mediated lateral inhibition may thus act at each developmental branchpoint to drive neighbouring cells along different developmental pathways. Our findings indicate that the sensory patches of the vertebrate inner ear and the sensory bristles of a fly are generated by minor variations of the same basic developmental program, in which cell diversification driven by Delta-Notch and/or Serrate-Notch signalling plays a central part.

scholarly journals Distribution of immunoreactive alpha- and beta-subunit isoforms of Na,K-ATPase in the gerbil inner ear.

1994 ◽  
Vol 42 (7) ◽  
pp. 843-853 ◽  
Author(s):  
J P McGuirt ◽  
B A Schulte
Keyword(s):  
Inner Ear ◽  
Cell Types ◽  
Beta Subunit ◽  
Atpase Subunit ◽  
New Information ◽  
Positive Immunostaining ◽  
Subunit Isoforms ◽  
Marginal Cells ◽  
Ganglion Neurons ◽  
Vestibular Dark Cells

Biochemical and histochemical studies have demonstrated abundant Na,K-ATPase in the inner ear and provided new information concerning the ion transport capacities of specialized cell types. To extend these earlier observations, we immunostained inner ears from adult gerbils with antibodies specific for the three known alpha- and the two known beta-isoforms of Na,K-ATPase. Different inner ear cell types contained specific and distinct combinations of alpha- and beta-subunit isoforms. Strial marginal cells and vestibular dark cells expressed the alpha 1- and beta 2-isoforms, whereas other positive epithelial cells expressed alpha 1 in combination with beta 1. Ganglion neurons and their peripheral processes showed positive immunostaining for the alpha 3- and beta 1-subunit isoforms. Subpopulations of fibrocytes in the spiral prominence, suprastrial and supralimbal regions, and vestibular system expressed either the alpha 1- or alpha 2-isoform, or both. The differential expression of Na,K-ATPase subunit isoforms presumably reflects different K+ and Na+ transport capacities among inner ear cell types which, working in concert, serve to generate and maintain the unique ionic and electrical environment in the mammalian inner ear.

scholarly journals Potassium Ion Movement in the Inner Ear: Insights from Genetic Disease and Mouse Models

Physiology ◽  
2009 ◽  
Vol 24 (5) ◽  
pp. 307-316 ◽  
Author(s):  
Anselm A. Zdebik ◽  
Philine Wangemann ◽  
Thomas J. Jentsch
Keyword(s):  
Ion Transport ◽  
Inner Ear ◽  
Mouse Models ◽  
Hair Cells ◽  
Genetic Disease ◽  
Morphological Analysis ◽  
Stria Vascularis ◽  
Developmental Time ◽  
Sensory Transduction ◽  
Transport Mechanisms

Sensory transduction in the cochlea and vestibular labyrinth depends on fluid movements that deflect the hair bundles of mechanosensitive hair cells. Mechanosensitive transducer channels at the tip of the hair cell stereocilia allow K+ to flow into cells. This unusual process relies on ionic gradients unique to the inner ear. Linking genes to deafness in humans and mice has been instrumental in identifying the ion transport machinery important for hearing and balance. Morphological analysis is difficult in patients, but mouse models have helped to investigate phenotypes at different developmental time points. This review focuses on cellular ion transport mechanisms in the stria vascularis that generate the major electrochemical gradients for sensory transduction.

scholarly journals Release and Elementary Mechanisms of Nitric Oxide in Hair Cells

2010 ◽  
Vol 103 (5) ◽  
pp. 2494-2505 ◽  
Author(s):  
Ping Lv ◽  
Adrian Rodriguez-Contreras ◽  
Hyo Jeong Kim ◽  
Jun Zhu ◽  
Dongguang Wei ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Inner Ear ◽  
Hair Cells ◽  
Single Channel ◽  
Cell Types ◽  
Cellular Mechanism ◽  
Open Probability ◽  
Potential Oscillations ◽  
Efferent Nerve ◽  
Membrane Oscillations

The enzyme nitric oxide (NO) synthase, that produces the signaling molecule NO, has been identified in several cell types in the inner ear. However, it is unclear whether a measurable quantity of NO is released in the inner ear to confer specific functions. Indeed, the functional significance of NO and the elementary cellular mechanism thereof are most uncertain. Here, we demonstrate that the sensory epithelia of the frog saccule release NO and explore its release mechanisms by using self-referencing NO-selective electrodes. Additionally, we investigated the functional effects of NO on electrical properties of hair cells and determined their underlying cellular mechanism. We show detectable amounts of NO are released by hair cells (>50 nM). Furthermore, a hair-cell efferent modulator acetylcholine produces at least a threefold increase in NO release. NO not only attenuated the baseline membrane oscillations but it also increased the magnitude of current required to generate the characteristic membrane potential oscillations. This resulted in a rightward shift in the frequency–current relationship and altered the excitability of hair cells. Our data suggest that these effects ensue because NO reduces whole cell Ca2+ current and drastically decreases the open probability of single-channel events of the L-type and non L-type Ca2+ channels in hair cells, an effect that is mediated through direct nitrosylation of the channel and activation of protein kinase G. Finally, NO increases the magnitude of Ca2+-activated K+ currents via direct NO nitrosylation. We conclude that NO-mediated inhibition serves as a component of efferent nerve modulation of hair cells.

scholarly journals Cochlear protein biomarkers as potential sites for targeted inner ear drug delivery

2019 ◽  
Vol 10 (2) ◽  
pp. 368-379
Author(s):  
James G. Naples ◽  
Lauren E. Miller ◽  
Andrew Ramsey ◽  
Daqing Li
Keyword(s):  
Drug Delivery ◽  
Inner Ear ◽  
Ganglion Cells ◽  
Stria Vascularis ◽  
Spiral Ganglion ◽  
Cell Types ◽  
Protein Biomarkers ◽  
Single Location ◽  
Specific Manner ◽  
The Many

AbstractThe delivery of therapies to the cochlea is notoriously challenging. It is an organ protected by a number of barriers that need to be overcome in the drug delivery process. Additionally, there are multiple sites of possible damage within the cochlea. Despite the many potential sites of damage, acquired otologic insults preferentially damage a single location. While progress has been made in techniques for inner ear drug delivery, the current techniques remain non-specific and our ability to deliver therapies in a cell-specific manner are limited. Fortunately, there are proteins specific to various cell-types within the cochlea (e.g., hair cells, spiral ganglion cells, stria vascularis) that function as biomarkers of site-specific damage. These protein biomarkers have potential to serve as targets for cell-specific inner ear drug delivery. In this manuscript, we review the concept of biomarkers and targeted- inner ear drug delivery and the well-characterized protein biomarkers within each of the locations of interest within the cochlea. Our review will focus on targeted drug delivery in the setting of acquired otologic insults (e.g., ototoxicity, noise-induce hearing loss). The goal is not to discuss therapies to treat acquired otologic insults, rather, to establish potential concepts of how to deliver therapies in a targeted, cell-specific manner. Based on our review, it is clear that future of inner ear drug delivery is a discipline filled with potential that will require collaborative efforts among clinicians and scientists to optimize treatment of otologic insults.

scholarly journals Organotypic Cocultures of Human Pluripotent Stem Cell Derived-Neurons with Mammalian Inner Ear Hair Cells and Cochlear Nucleus Slices

2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
Tomoko Hyakumura ◽  
Stuart McDougall ◽  
Sue Finch ◽  
Karina Needham ◽  
Mirella Dottori ◽  
...  
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Inner Ear ◽  
Hair Cells ◽  
Cochlear Nucleus ◽  
Cell Types ◽  
Quantitative Evidence ◽  
Brainstem Slice

Stem cells have been touted as a source of potential replacement neurons for inner ear degeneration for almost two decades now; yet to date, there are few studies describing the use of human pluripotent stem cells (hPSCs) for this purpose. If stem cell therapies are to be used clinically, it is critical to validate the usefulness of hPSC lines in vitro and in vivo. Here, we present the first quantitative evidence that differentiated hPSC-derived neurons that innervate both the inner ear hair cells and cochlear nucleus neurons in coculture, with significantly more new synaptic contacts formed on target cell types. Nascent contacts between stem cells and hair cells were immunopositive for both synapsin I and VGLUT1, closely resembling expression of these puncta in endogenous postnatal auditory neurons and control cocultures. When hPSCs were cocultured with cochlear nucleus brainstem slice, significantly greater numbers of VGLUT1 puncta were observed in comparison to slice alone. New VGLUT1 puncta in cocultures with cochlear nucleus slice were not significantly different in size, only in quantity. This experimentation describes new coculture models for assessing auditory regeneration using well-characterised hPSC-derived neurons and highlights useful methods to quantify the extent of innervation on different cell types in the inner ear and brainstem.

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