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Harada S, Koyama Y, Yoshioka Y, Inohara H, Shimada S. Visualization of Reissner's membrane in the mouse inner ear using highly sensitive magnetic resonance imaging analysis. Biochem Biophys Res Commun 2024; 723:150153. [PMID: 38820624 DOI: 10.1016/j.bbrc.2024.150153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2024] [Accepted: 05/20/2024] [Indexed: 06/02/2024]
Abstract
Although research on hearing loss, including the identification of causative genes, has become increasingly active, the pathogenic mechanism of hearing loss remains unclear. One of the reasons for this is that the structure of the inner ear of mice, which is commonly used as a genetically modified animal model, is too small and complex, making it difficult to accurately capture abnormalities and dynamic changes in vivo. Especially, Reissner's membrane is a very important structure that separates the perilymph and endolymph of the inner ear. This malformation or damage induces abnormalities in hearing and balance. Until now, imaging analyses, such as magnetic resonance imaging (MRI) and computed tomography, are performed to investigate the inner ear structure in vivo; however, it has been difficult to analyze the small inner ear structure of mice owing to resolution. Therefore, there is an urgent need to develop an image analysis method that can accurately capture the structure of the inner ear of mice including Reissner's membrane, both dynamically and statically. This study aimed to investigate whether it is possible to accurately capture the structure (e.g., Reissner's membrane) and abnormalities of the inner ear of mice using an 11.7 T MRI. By combining two types of MRI methods, in vivo and ex vivo, we succeeded for the first time in capturing the fine structure of the normal mouse inner ear, such as the Reissner's membrane, and inflammatory lesions of otitis media mouse models in detail and accurately. In the future, we believe that understanding the state of Reissner's membrane during living conditions will greatly contribute to the development of research on inner ear issues, such as hearing loss.
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Affiliation(s)
- Shotaro Harada
- Department of Neuroscience and Cell Biology, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan; Department of Otorhinolaryngology-Head and Neck Surgery, Osaka University Graduate School of Medicine, Suita, Osaka 565-0871, Japan
| | - Yoshihisa Koyama
- Department of Neuroscience and Cell Biology, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan; Addiction Research Unit, Osaka Psychiatric Research Center, Osaka Psychiatric Medical Center, Osaka, 541-8567, Japan; Global Center for Medical Engineering and Informatics, Osaka University, Suita, 565-0871, Japan; Integrated Frontier Research for Medical Science Division, Institute for Open and Transdisciplinary Research Initiatives (OTRI), Osaka University, Suita 565-0871, Japan.
| | - Yoshichika Yoshioka
- Graduate School of Frontier Biosciences, Osaka University, Osaka 565-0871, Japan; Center for Information and Neural Networks, National Institute of Information and Communications Technology (NICT) and Osaka University, Osaka 565-0871, Japan; Institute for Open and Transdisciplinary Research Initiatives, Osaka University, Osaka 565-0871, Japan.
| | - Hidenori Inohara
- Department of Otorhinolaryngology-Head and Neck Surgery, Osaka University Graduate School of Medicine, Suita, Osaka 565-0871, Japan.
| | - Shoichi Shimada
- Department of Neuroscience and Cell Biology, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan; Addiction Research Unit, Osaka Psychiatric Research Center, Osaka Psychiatric Medical Center, Osaka, 541-8567, Japan; Global Center for Medical Engineering and Informatics, Osaka University, Suita, 565-0871, Japan.
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Fitzakerley JL, Trachte GJ. Genetics of guanylyl cyclase pathways in the cochlea and their influence on hearing. Physiol Genomics 2018; 50:780-806. [PMID: 29958079 DOI: 10.1152/physiolgenomics.00056.2018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Although hearing loss is the most common sensory deficit in Western societies, there are no successful pharmacological treatments for this disorder. Recent experiments have demonstrated that manipulation of intracellular cyclic guanosine monophosphate (cGMP) concentrations can have both beneficial and harmful effects on hearing. In this review, we will examine the role of cGMP as a key second messenger involved in many aspects of cochlear function and discuss the known functions of downstream effectors of cGMP in sound processing. The nitric oxide-stimulated soluble guanylyl cyclase system (sGC) and the two natriuretic peptide-stimulated particulate GCs (pGCs) will be more extensively covered because they have been studied most thoroughly. The cochlear GC systems are attractive targets for medical interventions that improve hearing while simultaneously representing an under investigated source of sensorineural hearing loss.
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Affiliation(s)
- Janet L Fitzakerley
- Department of Biomedical Sciences, University of Minnesota Medical School , Duluth, Minnesota
| | - George J Trachte
- Department of Biomedical Sciences, University of Minnesota Medical School , Duluth, Minnesota
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Glueckert R, Johnson Chacko L, Rask-Andersen H, Liu W, Handschuh S, Schrott-Fischer A. Anatomical basis of drug delivery to the inner ear. Hear Res 2018; 368:10-27. [PMID: 30442227 DOI: 10.1016/j.heares.2018.06.017] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 06/16/2018] [Accepted: 06/25/2018] [Indexed: 12/19/2022]
Abstract
The isolated anatomical position and blood-labyrinth barrier hampers systemic drug delivery to the mammalian inner ear. Intratympanic placement of drugs and permeation via the round- and oval window are established methods for local pharmaceutical treatment. Mechanisms of drug uptake and pathways for distribution within the inner ear are hard to predict. The complex microanatomy with fluid-filled spaces separated by tight- and leaky barriers compose various compartments that connect via active and passive transport mechanisms. Here we provide a review on the inner ear architecture at light- and electron microscopy level, relevant for drug delivery. Focus is laid on the human inner ear architecture. Some new data add information on the human inner ear fluid spaces generated with high resolution microcomputed tomography at 15 μm resolution. Perilymphatic spaces are connected with the central modiolus by active transport mechanisms of mesothelial cells that provide access to spiral ganglion neurons. Reports on leaky barriers between scala tympani and the so-called cortilymph compartment likely open the best path for hair cell targeting. The complex barrier system of tight junction proteins such as occludins, claudins and tricellulin isolates the endolymphatic space for most drugs. Comparison of relevant differences of barriers, target cells and cell types involved in drug spread between main animal models and humans shall provide some translational aspects for inner ear drug applications.
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Affiliation(s)
- R Glueckert
- Department of Otolaryngology, Medical University of Innsbruck, Innsbruck, Austria; University Clinics Innsbruck, Tirol Kliniken, University Clinic for Ear, Nose and Throat Medicine Innsbruck, Austria.
| | - L Johnson Chacko
- Department of Otolaryngology, Medical University of Innsbruck, Innsbruck, Austria
| | - H Rask-Andersen
- Department of Surgical Sciences, Section of Otolaryngology, Uppsala University Hospital, SE-751 85, Uppsala, Sweden
| | - W Liu
- Department of Surgical Sciences, Section of Otolaryngology, Uppsala University Hospital, SE-751 85, Uppsala, Sweden
| | - S Handschuh
- VetImaging, VetCore Facility for Research, University of Veterinary Medicine, Vienna, Austria
| | - A Schrott-Fischer
- Department of Otolaryngology, Medical University of Innsbruck, Innsbruck, Austria
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Qin L, Zhang B, Wang Q, Li D, Luo X, Zhong S. Effect of aldosterone on cochlear Af9 expression and hearing in guinea pig. Acta Otolaryngol 2017; 137:903-909. [PMID: 28399691 DOI: 10.1080/00016489.2017.1309681] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
CONCLUSIONS Af9 protein in cochlea may be closely related to endolymph regulation by aldosterone and thus may be involved in pathogenesis of endolymphatic hydrops (EH). OBJECTIVES EH is the pathological characteristic of Ménière's disease (MD). Aldosterone could induce EH, but its relationship with MD is still controversial. The aim of the present study is to investigate the Af9 protein expression in guinea pig cochlea and regulation of Af9 expression and cochlear function by aldosterone. The role of Af9 in pathogenesis of EH is discussed. METHODS Thirty guinea pigs were randomly divided into two groups. The treatment group was intraperitoneally injected with aldosterone 0.1 mg/kg/d for 5 days, while the control group was done with saline. Hearing and histomorphology of cochlea were examined. In addition, expression of Af9 protein was studied. RESULTS The hearing threshold of the treatment group was increased. EH was induced in 73% of guinea pigs in the treatment group, and no EH was found in the control group. Af9 protein was found in spiral limbus, stria vascularis, Reissner's membrane, organ of Corti and spiral ganglion in both groups. Af9 expression in cochlea decreased significantly at protein level after treatment by aldosterone.
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Affiliation(s)
- Li Qin
- Department of Otolaryngology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Biyun Zhang
- Department of Otolaryngology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Qianying Wang
- Department of Otolaryngology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Duanchao Li
- Department of Otolaryngology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Xiaoli Luo
- Department of Otolaryngology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Shixun Zhong
- Department of Otolaryngology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
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Miyazaki H, Wangemann P, Marcus DC. The gastric H,K-ATPase in stria vascularis contributes to pH regulation of cochlear endolymph but not to K secretion. BMC PHYSIOLOGY 2016; 17:1. [PMID: 27515813 PMCID: PMC4982335 DOI: 10.1186/s12899-016-0024-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Accepted: 07/29/2016] [Indexed: 01/22/2023]
Abstract
BACKGROUND Disturbance of acid-base balance in the inner ear is known to be associated with hearing loss in a number of conditions including genetic mutations and pharmacologic interventions. Several previous physiologic and immunohistochemical observations lead to proposals of the involvement of acid-base transporters in stria vascularis. RESULTS We directly measured acid flux in vitro from the apical side of isolated stria vascularis from adult C57Bl/6 mice with a novel constant-perfusion pH-selective self-referencing probe. Acid efflux that depended on metabolism and ion transport was observed from the apical side of stria vascularis. The acid flux was decreased to about 40 % of control by removal of the metabolic substrate (glucose-free) and by inhibition of the sodium pump (ouabain). The flux was also decreased a) by inhibition of Na,H-exchangers by amiloride, dimethylamiloride (DMA), S3226 and Hoe694, b) by inhibition of Na,2Cl,K-cotransporter (NKCC1) by bumetanide, and c) by the likely inhibition of HCO3/anion exchange by DIDS. By contrast, the acid flux was increased by inhibition of gastric H,K-ATPase (SCH28080) but was not affected by an inhibitor of vH-ATPase (bafilomycin). K flux from stria vascularis was reduced less than 5 % by SCH28080. CONCLUSIONS These observations suggest that stria vascularis may be an important site of control of cochlear acid-base balance and demonstrate a functional role of several acid-base transporters in stria vascularis, including basolateral H,K-ATPase and apical Na,H-exchange. Previous suggestions that H secretion is mediated by an apical vH-ATPase and that basolateral H,K-ATPase contributes importantly to K secretion in stria vascularis are not supported. These results advance our understanding of inner ear acid-base balance and provide a stronger basis to interpret the etiology of genetic and pharmacologic cochlear dysfunctions that are influenced by endolymphatic pH.
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Affiliation(s)
- Hiromitsu Miyazaki
- Department of Anatomy & Physiology, Cellular Biophysics Laboratory, Kansas State University, 228 Coles Hall, Manhattan, KS 66506-5802 USA
- Deparment of Anatomy & Physiology, Cell Physiology Laboratory, Kansas State University, 228 Coles Hall, Manhattan, KS 66506-5802 USA
- Department of Otolaryngology-Head and Neck Surgery, Tohoku University Graduate School of Medicine, Sendai, 980-8574 Japan
| | - Philine Wangemann
- Deparment of Anatomy & Physiology, Cell Physiology Laboratory, Kansas State University, 228 Coles Hall, Manhattan, KS 66506-5802 USA
| | - Daniel C. Marcus
- Department of Anatomy & Physiology, Cellular Biophysics Laboratory, Kansas State University, 228 Coles Hall, Manhattan, KS 66506-5802 USA
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Kim KX, Sanneman JD, Kim HM, Harbidge DG, Xu J, Soleimani M, Wangemann P, Marcus DC. Slc26a7 chloride channel activity and localization in mouse Reissner's membrane epithelium. PLoS One 2014; 9:e97191. [PMID: 24810589 PMCID: PMC4014619 DOI: 10.1371/journal.pone.0097191] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Accepted: 04/16/2014] [Indexed: 11/19/2022] Open
Abstract
Several members of the SLC26 gene family have highly-restricted expression patterns in the auditory and vestibular periphery and mutations in mice of at least two of these (SLC26A4 and SLC26A5) lead to deficits in hearing and/or balance. A previous report pointed to SLC26A7 as a candidate gene important for cochlear function. In the present study, inner ears were assayed by immunostaining for Slc26a7 in neonatal and adult mice. Slc26a7 was detected in the basolateral membrane of Reissner’s membrane epithelial cells but not neighboring cells, with an onset of expression at P5; gene knockout resulted in the absence of protein expression in Reissner’s membrane. Whole-cell patch clamp recordings revealed anion currents and conductances that were elevated for NO3− over Cl− and inhibited by I− and NPPB. Elevated NO3− currents were absent in Slc26a7 knockout mice. There were, however, no major changes to hearing (auditory brainstem response) of knockout mice during early adult life under constitutive and noise exposure conditions. The lack of Slc26a7 protein expression found in the wild-type vestibular labyrinth was consistent with the observation of normal balance. We conclude that SLC26A7 participates in Cl− transport in Reissner’s membrane epithelial cells, but that either other anion pathways, such as ClC-2, possibly substitute satisfactorily under the conditions tested or that Cl− conductance in these cells is not critical to cochlear function. The involvement of SLC26A7 in cellular pH regulation in other epithelial cells leaves open the possibility that SLC26A7 is needed in Reissner’s membrane cells during local perturbations of pH.
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Affiliation(s)
- Kyunghee X. Kim
- Anatomy & Physiology Department, Cellular Biophysics Laboratory, Kansas State University, Manhattan, Kansas, United States of America
| | - Joel D. Sanneman
- Anatomy & Physiology Department, Cell Physiology Laboratory, Kansas State University, Manhattan, Kansas, United States of America
| | - Hyoung-Mi Kim
- Anatomy & Physiology Department, Cell Physiology Laboratory, Kansas State University, Manhattan, Kansas, United States of America
| | - Donald G. Harbidge
- Anatomy & Physiology Department, Cellular Biophysics Laboratory, Kansas State University, Manhattan, Kansas, United States of America
| | - Jie Xu
- Department of Medicine and Center on Genetics of Transport, University of Cincinnati, Cincinnati, Ohio, United States of America
| | - Manoocher Soleimani
- Department of Medicine and Center on Genetics of Transport, University of Cincinnati, Cincinnati, Ohio, United States of America
| | - Philine Wangemann
- Anatomy & Physiology Department, Cell Physiology Laboratory, Kansas State University, Manhattan, Kansas, United States of America
| | - Daniel C. Marcus
- Anatomy & Physiology Department, Cellular Biophysics Laboratory, Kansas State University, Manhattan, Kansas, United States of America
- * E-mail:
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Gabrielli L, Bonasoni MP, Santini D, Piccirilli G, Chiereghin A, Guerra B, Landini MP, Capretti MG, Lanari M, Lazzarotto T. Human fetal inner ear involvement in congenital cytomegalovirus infection. Acta Neuropathol Commun 2013; 1:63. [PMID: 24252374 PMCID: PMC3893406 DOI: 10.1186/2051-5960-1-63] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Accepted: 09/23/2013] [Indexed: 01/12/2023] Open
Abstract
Background Congenital cytomegalovirus (CMV) infection is a leading cause of sensorineural hearing loss (SNHL). The mechanisms of pathogenesis of CMV-related SNHL are still unclear. The aim is to study congenital CMV-related damage in the fetal inner ear, in order to better understand the underlying pathophysiology behind CMV-SNHL. Results We studied inner ears and brains of 20 human fetuses, all at 21 week gestational age, with a high viral load in the amniotic fluid, with and without ultrasound (US) brain abnormalities. We evaluated histological brain damage, inner ear infection, local inflammatory response and tissue viral load. Immunohistochemistry revealed that CMV was positive in 14/20 brains (70%) and in the inner ears of 9/20 fetuses (45%). In the cases with inner ear infection, the marginal cell layer of the stria vascularis was always infected, followed by infection in the Reissner’s membrane. The highest tissue viral load was observed in the inner ear with infected Organ of Corti. Vestibular labyrinth showed CMV infection of sensory cells in the utricle and in the crista ampullaris. US cerebral anomalies were detected in 6 cases, and in all those cases, the inner ear was always involved. In the other 14 cases with normal brain scan, histological brain damage was present in 8 fetuses and 3 of them presented inner ear infection. Conclusions CMV-infection of the marginal cell layer of the stria vascularis may alter potassium and ion circulation, dissipating the endocochlear potential with consequent SNHL. Although abnormal cerebral US is highly predictive of brain and inner ear damage, normal US findings cannot exclude them either.
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Yamazaki M, Wu T, Pondugula SR, Harbidge DG, Marcus DC. Sodium selectivity of semicircular canal duct epithelial cells. BMC Res Notes 2011; 4:355. [PMID: 21914199 PMCID: PMC3180474 DOI: 10.1186/1756-0500-4-355] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Accepted: 09/13/2011] [Indexed: 11/16/2022] Open
Abstract
Background Sodium absorption by semicircular canal duct (SCCD) epithelial cells is thought to contribute to the homeostasis of the volume of vestibular endolymph. It was previously shown that the epithelial cells could absorb Na+ under control of a glucocorticoid hormone (dexamethasone) and the absorptive transepithelial current was blocked by amiloride. The most commonly-observed target of amiloride is the epithelial sodium channel (ENaC), comprised of the three subunits α-, β- and γ-ENaC. However, other cation channels have also been observed to be sensitive in a similar concentration range. The aim of this study was to determine whether SCCD epithelial cells absorb only Na+ or also K+ through an amiloride-sensitive pathway. Parasensory K+ absorption could contribute to regulation of the transduction current through hair cells, as found to occur via vestibular transitional cells [S. H. Kim and D. C. Marcus. Regulation of sodium transport in the inner ear. Hear.Res. doi:10.1016/j.heares.2011.05.003, 2011]. Results We determined the molecular and functional expression of candidate cation channels with gene array (GEO GSE6197), whole-cell patch clamp and transepithelial recordings in primary cultures of rat SCCD. α-, β- and γ-ENaC were all previously reported as present. The selectivity of the amiloride-sensitive transepithelial and cell membrane currents was observed in Ussing chamber and whole-cell patch clamp recordings. The cell membrane currents were carried by Na+ but not K+, but the Na+ selectivity disappeared when the cells were cultured on impermeable supports. Transepithelial currents across SCCD were also carried exclusively by Na+. Conclusions These results are consistent with the amiloride-sensitive absorptive flux of SCCD mediated by a highly Na+-selective channel, likely αβγ-ENaC. These epithelial cells therefore absorb only Na+ via the amiloride-sensitive pathway and do not provide a parasensory K+ efflux from the canals via this pathway. The results further provide caution to the culture of epithelial cells on impermeable surfaces.
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Affiliation(s)
- Muneharu Yamazaki
- Cellular Biophysics Laboratory, Department of Anatomy & Physiology, Kansas State University, Manhattan, KS 66506, USA.
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Kim SH, Marcus DC. Regulation of sodium transport in the inner ear. Hear Res 2011; 280:21-9. [PMID: 21620939 DOI: 10.1016/j.heares.2011.05.003] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Revised: 04/27/2011] [Accepted: 05/02/2011] [Indexed: 12/31/2022]
Abstract
Na(+) concentrations in endolymph must be controlled to maintain hair cell function since the transduction channels of hair cells are cation-permeable, but not K(+)-selective. Flooding or fluctuations of the hair cell cytosol with Na(+) would be expected to lead to cellular dysfunction, hearing loss and vertigo. This review briefly describes cellular mechanisms known to be responsible for Na(+) homeostasis in each compartment of the inner ear, including the cochlea, saccule, semicircular canals and endolymphatic sac. The influx of Na(+) into endolymph of each of the organs is likely via passive diffusion, but these pathways have not yet been identified or characterized. Na(+) absorption is controlled by gate-keeper channels in the apical (endolymphatic) membrane of the transporting cells. Highly Na(+)-selective epithelial sodium channels (ENaCs) control absorption by Reissner's membrane, saccular extramacular epithelium, semicircular canal duct epithelium and endolymphatic sac. ENaC activity is controlled by a number of signal pathways, but most notably by genomic regulation of channel numbers in the membrane via glucocorticoid signaling. Non-selective cation channels in the apical membrane of outer sulcus epithelial cells and vestibular transitional cells mediate Na(+) and parasensory K(+) absorption. The K(+)-mediated transduction current in hair cells is also accompanied by a Na(+) flux since the transduction channels are non-selective cation channels. Cation absorption by all of these cells is regulated by extracellular ATP via apical non-selective cation channels (P2X receptors). The heterogeneous population of epithelial cells in the endolymphatic sac is thought to have multiple absorptive pathways for Na(+) with regulatory pathways that include glucocorticoids and purinergic agonists.
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Affiliation(s)
- Sung Huhn Kim
- Department of Otorhinolaryngology, Yonsei University College of Medicine, 250 Seongsanno, Seodaemun-gu, Seoul 120-752, Republic of Korea
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