scholarly journals Immunohistochemical Investigation of Nerve Fibers among the Cochlear Supporting Cells with the Combination of Antigen Retrieval and Signal Amplification Method

2003 ◽  
Vol 36 (1) ◽  
pp. 37-41
Author(s):  
Shigenori Suzuki ◽  
Hiro-oki Okamura ◽  
Iwao Ohtani
Author(s):  
Hong-Bo Zhao ◽  
Li-Man Liu ◽  
Ning Yu ◽  
Yan Zhu ◽  
Ling Mei ◽  
...  

It is critical for hearing that the descending cochlear efferent system provide a negative feedback to hair cells to regulate hearing sensitivity and provide the protection of hearing from noise. Here, we report that the medial olivocochlear (MOC) efferent nerves, which project to outer hair cells (OHCs), also could innervate OHC surrounding supporting cells (SCs) to regulate hearing sensitivity. MOC nerve fibers are cholinergic and acetylcholine (ACh) is a primary neurotransmitter. MOC nerve endings, presynaptic vesicular acetylcholine transporters (VAChT), and postsynaptic ACh receptors were visible in SCs and the SC area. Application of ACh in the SC could evoke a typical inward current, which reduced gap junctions (GJs) between SCs and consequently declined OHC electromotility, which is an active cochlear amplification and can increase hearing sensitivity. This indirect, GJ-mediated inhibition enhanced the direct inhibition of ACh on OHC electromotility but had long-lasting influence. In vivo experiments further demonstrated that deficiency of this GJ-mediated efferent pathway declined the regulation of active cochlear amplification and compromised the protection against noise. In particular, distortion production otoacoustic emission (DPOAE) showed a delayed reduction after noise exposure. Our findings reveal a new pathway for the MOC efferent system via innervating SCs to control active cochlear amplification and hearing sensitivity. These data also suggest that this GJ-mediated efferent pathway may play a critical role in the long-term efferent inhibition and is required for protecting hearing from noise trauma.


2020 ◽  
Author(s):  
Hong-Bo Zhao ◽  
Li-Man Liu ◽  
Ling Mei ◽  
Ning Yu ◽  
Jin Chen ◽  
...  

It is critical for hearing that the descending cochlear efferent system provide negative feedback to hair cells to regulate hearing sensitivity and provide protection from noise. The medial olivocochlear (MOC) efferent nerves project to outer hair cells (OHCs) and inhibit OHC electromotility, which is an active cochlear amplification and can increase hearing sensitivity. Here, we report that the MOC efferent nerves also have functional innervation with the cochlear supporting cells to regulate hearing sensitivity. The MOC efferent nerve fibers and the corresponding MOC neurotransmitter acetylcholine (ACh) receptors were visible in the cochlear supporting cells. Application of ACh in the cochlear supporting cells could also evoke inward currents in a dose-dependent manner and reduced gap junctional (GJ) coupling between the cochlear supporting cells, which consequently declined electromotility in OHCs. This indirect inhibitory effect through the mediated GJs between the cochlear supporting cells on OHC electromotility was consistent and enhanced the direct inhibition of ACh on OHC electromotility but had long-lasting influence. In vivo experiments further demonstrated that deficiency of this GJ-mediated efferent control pathway declined the regulation of active cochlear amplification and impaired the protection from noise trauma. Our findings reveal a new pathway for the cochlear efferent system to control hearing sensitivity, and also demonstrate that this supporting cell GJ-mediated efferent pathway is critical for control of hearing sensitivity and the protection of hearing from noise trauma.


Micromachines ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 197
Author(s):  
Meiqing Liu ◽  
Haoran Li ◽  
Yanwei Jia ◽  
Pui-In Mak ◽  
Rui P. Martins

The emergence of the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a zoonotic pathogen, has led to the outbreak of coronavirus disease 2019 (COVID-19) pandemic and brought serious threats to public health worldwide. The gold standard method for SARS-CoV-2 detection requires both reverse transcription (RT) of the virus RNA to cDNA and then polymerase chain reaction (PCR) for the cDNA amplification, which involves multiple enzymes, multiple reactions and a complicated assay optimization process. Here, we developed a duplex-specific nuclease (DSN)-based signal amplification method for SARS-CoV-2 detection directly from the virus RNA utilizing two specific DNA probes. These specific DNA probes can hybridize to the target RNA at different locations in the nucleocapsid protein gene (N gene) of SARS-CoV-2 to form a DNA/RNA heteroduplex. DSN cleaves the DNA probe to release fluorescence, while leaving the RNA strand intact to be bound to another available probe molecule for further cleavage and fluorescent signal amplification. The optimized DSN amount, incubation temperature and incubation time were investigated in this work. Proof-of-principle SARS-CoV-2 detection was demonstrated with a detection sensitivity of 500 pM virus RNA. This simple, rapid, and direct RNA detection method is expected to provide a complementary method for the detection of viruses mutated at the PCR primer-binding regions for a more precise detection.


1967 ◽  
Vol 45 (1) ◽  
pp. 117-126 ◽  
Author(s):  
M. A. Hafeez ◽  
P. Ford

The morphohistology and some histochemical aspects of the pineal organ in the sockeye salmon were studied. The distal part of the organ lies in a pineal fossa in the cranial roof. Photosensory cells and two kinds of ependymal supporting cells are present throughout its epithelium, which is entirely devoid of either melanin or lipofuchsin. Besides sensory nerve fibers, efferent end-loops are present on the photosensory as well as the supporting cells. The dorsal pineal nerve tract probably contains both sensory and efferent fibers. The apocrine secretion of sensory as well as some supporting cells is probably associated with either the maintenance of a constant chemical composition of the cerebrospinal fluid or with supply of certain chemical substances to the brain tissue. The secretion in the pineal and the subcommissural organ consists of glycogen, mucopolysaccharides, mucoproteins, and aldehyde fuchsin positive granules.It is proposed that the pineal organ is photosensory as well as secretory and that its photosensitivity might be of some significance in the light-dependent behavior of this species in terms of intensity detection.


1979 ◽  
Vol 87 (6) ◽  
pp. 818-836 ◽  
Author(s):  
Joseph B. Nadol

Three human temporal bones with presbycusis affecting the basal turn of the cochlea were studied by light and electron microscopy. Conditions in two ears examined by light microscopy were typical of primary neural degeneration, with a descending audiometric pattern, loss of cochlear neurons in the basal turn, and preservation of the organ of Corti. Ultrastructural analysis revealed normal hair cells and marked degenerative changes of the remaining neural fibers, especially in the basal turn. These changes included a decrease in the number of synapses at the base of hair cells, accumulation of cellular debris in the spiral bundles, abnormalities of the dendritic fibers and their sheaths in the osseous spiral lamina, and degenerative changes in the spiral ganglion cells and axons. These changes were interpreted as an intermediate stage of degeneration prior to total loss of nerve fibers and ganglion cells as visualized by light microscopy. In the third ear the changes observed were typical of primary degeneration of hair and supporting cells in the basal turn with secondary neural degeneration. Additional observations at an ultrastructural level included maintenance of the tight junctions of the scala media despite loss of both hair and supporting cells, suggesting a capacity for cellular “healing” in the inner ear. Degenerative changes were found in the remaining neural fibers in the osseous spiral lamina. In addition, there was marked thickening of the basilar membrane in the basal turn, which consisted of an increased number of fibrils and an accumulation of amorphous osmiophilic material in the basilar membrane. This finding supports the concept that mechanical alterations may occur in presbycusis of the basal turn.


2008 ◽  
Vol 120 (49) ◽  
pp. 9660-9663 ◽  
Author(s):  
Jung Rok Lee ◽  
Juhee Lee ◽  
Sang Kyung Kim ◽  
Kwang Pyo Kim ◽  
Hyung Soon Park ◽  
...  

2019 ◽  
Author(s):  
Jingyuan Zhang ◽  
Daxiang Na ◽  
Miriam Dilts ◽  
Kenneth S. Henry ◽  
Patricia M. White

AbstractNoise induced hearing loss (NIHL) affects over ten million adults in the United States, and there is no biological treatment to restore endogenous function after damage. We hypothesized that activation of signaling from ERBB2 receptors in cochlear supporting cells could mitigate NIHL damage. We used the Tet-On genetic expression system to drive a constitutively active variant of ERBB2 (CA-ERBB2) in cochlear supporting cells three days after permanent noise damage in young adult mice. Hearing thresholds were assessed with auditory brainstem response tests prior to noise damage, and hearing recovery was assessed over a three month period. We evaluated supporting cell proliferation, inner and outer hair cell (IHC and OHC) survival, synaptic preservation, and IHC cytoskeletal alterations with histological techniques. Mice harboring CA-ERBB2 capability had similar hearing thresholds to control littermates prior to and immediately after noise exposure, and incurred similar levels of permanent hearing loss. Two and three months after noise exposure, CA-ERBB2+ mice demonstrated a partial but significant reversal of NIHL threshold shifts at the lowest frequency tested, out of five frequencies (n=19 total mice, p=0.0015, ANOVA). We also observed improved IHC and OHC survival (n=7 total cochleae, p=5 × 10−5, Kruskal-Wallis rank sum test). There was no evidence for sustained supporting cell proliferation. Some mortality was associated with doxycycline and furosemide treatments to induce the Tet-ON system. These data suggest that ERBB2 signaling in supporting cells promotes HC repair and some functional recovery. Funded by NIH R01 DC014261, and grants from the Schmitt Foundation and UR Ventures.


2020 ◽  
Vol 28 (3) ◽  
pp. 141-148
Author(s):  
Saroj Kumar Ghosh

AbstractCharacteristic features of histology and fine morphology of the olfactory organ in the tank goby, Glossogobius giuris (Perciformes, Gobiidae, Gobiinae), were investigated with light and scanning electron microscopy. The olfactory cavity contained single lamellae that were exposed to the aquatic environment by small anterior and posterior nostrils. Typical olfactory rosettes were not observed. Histologically, each lamella consisted of two layers of epithelium; wrapping the central core that was composed of connective tissue stroma with nerve fibers and blood capillaries. The mucosal lining of lamella was merged with sensory and non-sensory olfactory cells, identified on the basis of structural characters, surface specializations, and staining features. The principal sensory elements were ciliated receptor cells that were characterized by apical dendritic processes expanded from cell soma and microvillous receptor cells equipped with multiple tiny dendrons on the mucosal surface. The bead-like appearance of several labyrinth cells, mucous cells with secreted mucin, scattered lymphatic cells, stratified epithelial cells bearing microfolds, and condensed ciliated supporting cells were observed in the non-sensory epithelia. Undifferentiated basal cells were embedded in the deeper zone of the epithelium above the basement membrane. The cellular organization of the olfactory lining was interpreted with chemoreception of the fish concerned.


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