1
|
Chachlaki K, Prevot V. Nitric oxide signalling in the brain and its control of bodily functions. Br J Pharmacol 2020; 177:5437-5458. [PMID: 31347144 PMCID: PMC7707094 DOI: 10.1111/bph.14800] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 07/10/2019] [Accepted: 07/19/2019] [Indexed: 02/06/2023] Open
Abstract
Nitric oxide (NO) is a versatile molecule that plays key roles in the development and survival of mammalian species by endowing brain neuronal networks with the ability to make continual adjustments to function in response to moment-to-moment changes in physiological input. Here, we summarize the progress in the field and argue that NO-synthetizing neurons and NO signalling in the brain provide a core hub for integrating sensory- and homeostatic-related cues, control key bodily functions, and provide a potential target for new therapeutic opportunities against several neuroendocrine and behavioural abnormalities.
Collapse
Affiliation(s)
- Konstantina Chachlaki
- Inserm, Laboratory of Development and Plasticity of the Neuroendocrine BrainJean‐Pierre Aubert Research Centre, UMR‐S 1172LilleFrance
- School of MedicineUniversity of LilleLilleFrance
- CHU LilleFHU 1,000 days for HealthLilleFrance
| | - Vincent Prevot
- Inserm, Laboratory of Development and Plasticity of the Neuroendocrine BrainJean‐Pierre Aubert Research Centre, UMR‐S 1172LilleFrance
- School of MedicineUniversity of LilleLilleFrance
- CHU LilleFHU 1,000 days for HealthLilleFrance
| |
Collapse
|
2
|
Yee KT, Neupane B, Bai F, Vetter DE. Zika virus infection causes widespread damage to the inner ear. Hear Res 2020; 395:108000. [PMID: 32623238 DOI: 10.1016/j.heares.2020.108000] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 02/07/2020] [Accepted: 05/20/2020] [Indexed: 12/20/2022]
Abstract
Zika virus (ZIKV) has been recently recognized as a causative agent of newborn microcephaly, as well as other neurological consequences. A less well recognized comorbidity of prenatal ZIKV infection is hearing loss, but cases of hearing impairment following adult ZIKV infection have also been recognized. Diminished hearing following prenatal ZIKV infection in a mouse model has been reported, but no cellular consequences were observed. We examined the effects of ZIKV infection on inner ear cellular integrity and expression levels of various proteins important for cochlear function in type I interferon receptor null (Ifnar1-/-) mice following infection at 5-6 weeks of age. We show that ZIKV antigens are present in cells within the cochlear epithelium, lateral wall, spiral limbus and spiral ganglion. Here we show that ZIKV infection alters cochlear expression of genes that signal cell damage (S100B), transport fluids (AQP1), are gaseous transmitters (eNOs) and modulate immune response (F4/80). Morphological analyses shows that not only are cochlear structures compromised by ZIKV infection, but damage also occurs in vestibular end organs. ZIKV produces a graded distribution of cellular damage in the cochlea, with greatest damage in the apex similar to that reported for cytomegalovirus (CMV) infection. The graded distribution of damage may indicate a differential susceptibility to ZIKV along the cochlear tonotopic axis. Collectively, these data are the first to show the molecular and morphological damage to the inner ear induced by ZIKV infection in adults and suggests multiple mechanisms contributing to the hearing loss reported in the human population.
Collapse
Affiliation(s)
- Kathleen T Yee
- Department of Neurobiology and Anatomical Sciences, University of Mississippi Medical Center, Jackson, MS, 39202, USA
| | - Biswas Neupane
- Department of Cell and Molecular Biology, University of Southern Mississippi, Hattiesburg, MS, 39406, USA
| | - Fengwei Bai
- Department of Cell and Molecular Biology, University of Southern Mississippi, Hattiesburg, MS, 39406, USA.
| | - Douglas E Vetter
- Department of Neurobiology and Anatomical Sciences, University of Mississippi Medical Center, Jackson, MS, 39202, USA.
| |
Collapse
|
3
|
Heinrich UR, Schmidtmann I, Meuser R, Ernst BP, Wünsch D, Siemer S, Gribko A, Stauber RH, Strieth S. Early Alterations of Endothelial Nitric Oxide Synthase Expression Patterns in the Guinea Pig Cochlea After Noise Exposure. J Histochem Cytochem 2019; 67:845-855. [PMID: 31510846 DOI: 10.1369/0022155419876644] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Constitutively expressed endothelial nitric oxide synthase (eNOS) is supposed to play a role in noise-induced nitric oxide (NO)-production. It is commonly known that intense noise exposure results in inducible NOS (iNOS) expression and increased NO-production, but knowledge about a contribution of the eNOS isoform is still lacking. Effects of noise exposure on eNOS immunolabeling were determined in male guinea pigs (n=24). For light microscopic analysis, 11 animals were exposed to 90 dB for 1 hr and 6 animals were used as controls. After exposure, eNOS immunostaining was performed on paraffin sections, and the staining intensities were quantified for 4 cochlear regions. For electron microscopic analysis, 2 animals were exposed for 2 hr to 90 dB and 5 animals were used as controls. The intensity of eNOS immunolabeling was found to be already comprehensively increased 1 hr after noise exposure to 90 dB. At the ultrastructural level, a clear increase in eNOS immunolabeling was found in microtubules-rich areas of cochlear cuticular structures. Hence, our findings indicate that the reticular lamina forming the endolymph-perilymph barrier at the apical side of the organ of Corti is involved in a fast intrinsic otoprotective mechanism of the cochlea.
Collapse
Affiliation(s)
- Ulf R Heinrich
- Department of Otorhinolaryngology, University Medical Center Mainz, Mainz, Germany
| | - Irene Schmidtmann
- Institute for Medical Biostatistics, Epidemiology and Informatics (IMBEI), University Medical Center Mainz, Mainz, Germany
| | - Regina Meuser
- Institute for Medical Biostatistics, Epidemiology and Informatics (IMBEI), University Medical Center Mainz, Mainz, Germany
| | - Benjamin P Ernst
- Department of Otorhinolaryngology, University Medical Center Mainz, Mainz, Germany
| | - Desiree Wünsch
- Department of Otorhinolaryngology, University Medical Center Mainz, Mainz, Germany
| | - Svenja Siemer
- Department of Otorhinolaryngology, University Medical Center Mainz, Mainz, Germany
| | - Alena Gribko
- Department of Otorhinolaryngology, University Medical Center Mainz, Mainz, Germany
| | - Roland H Stauber
- Department of Otorhinolaryngology, University Medical Center Mainz, Mainz, Germany
| | - Sebastian Strieth
- Department of Otorhinolaryngology, University Medical Center Mainz, Mainz, Germany
| |
Collapse
|
4
|
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.
Collapse
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
| |
Collapse
|
5
|
Möhrle D, Reimann K, Wolter S, Wolters M, Varakina K, Mergia E, Eichert N, Geisler HS, Sandner P, Ruth P, Friebe A, Feil R, Zimmermann U, Koesling D, Knipper M, Rüttiger L. NO-Sensitive Guanylate Cyclase Isoforms NO-GC1 and NO-GC2 Contribute to Noise-Induced Inner Hair Cell Synaptopathy. Mol Pharmacol 2017; 92:375-388. [DOI: 10.1124/mol.117.108548] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Accepted: 07/18/2017] [Indexed: 12/21/2022] Open
|
6
|
Mathews MA, Camp AJ, Murray AJ. Reviewing the Role of the Efferent Vestibular System in Motor and Vestibular Circuits. Front Physiol 2017; 8:552. [PMID: 28824449 PMCID: PMC5539236 DOI: 10.3389/fphys.2017.00552] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Accepted: 07/17/2017] [Indexed: 12/31/2022] Open
Abstract
Efferent circuits within the nervous system carry nerve impulses from the central nervous system to sensory end organs. Vestibular efferents originate in the brainstem and terminate on hair cells and primary afferent fibers in the semicircular canals and otolith organs within the inner ear. The function of this efferent vestibular system (EVS) in vestibular and motor coordination though, has proven difficult to determine, and remains under debate. We consider current literature that implicate corollary discharge from the spinal cord through the efferent vestibular nucleus (EVN), and hint at a potential role in overall vestibular plasticity and compensation. Hypotheses range from differentiating between passive and active movements at the level of vestibular afferents, to EVS activation under specific behavioral and environmental contexts such as arousal, predation, and locomotion. In this review, we summarize current knowledge of EVS circuitry, its effects on vestibular hair cell and primary afferent activity, and discuss its potential functional roles.
Collapse
Affiliation(s)
- Miranda A Mathews
- Sensory Systems and Integration Laboratory, Bosch Institute, Discipline of Biomedical Science, University of SydneySydney, NSW, Australia
| | - Aaron J Camp
- Sensory Systems and Integration Laboratory, Bosch Institute, Discipline of Biomedical Science, University of SydneySydney, NSW, Australia
| | - Andrew J Murray
- Sainsbury Wellcome Centre for Neural Circuits and Behaviour, University College LondonLondon, United Kingdom
| |
Collapse
|
7
|
Tamura A, Matsunobu T, Tamura R, Kawauchi S, Sato S, Shiotani A. Photobiomodulation rescues the cochlea from noise-induced hearing loss via upregulating nuclear factor κB expression in rats. Brain Res 2016; 1646:467-474. [PMID: 27342816 DOI: 10.1016/j.brainres.2016.06.031] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Revised: 06/16/2016] [Accepted: 06/20/2016] [Indexed: 12/12/2022]
Abstract
Photobiomodulation (PBM) is a noninvasive treatment that can be neuroprotective, although the underlying mechanisms remain unclear. In the present study, we assessed the mechanism of PBM as a novel treatment for noise-induced hearing loss, focusing on the nuclear factor (NF)-κB signaling pathway. Sprague-Dawley rats were exposed to 1-octave band noise centered at 4kHz for 5h (121dB). After noise exposure, their right ears were irradiated with an 808nm diode laser beam at an output power density of 165mW/cm(2) for 30min a day for 5 consecutive days. Measurement of the auditory brainstem response revealed an accelerated recovery of auditory function in the groups treated with PBM compared with the non-treatment group at 4, 7, and 14 days after noise exposure. Immunofluorescent image analysis for inducible nitric oxide synthase and cleaved caspase-3 showed lesser immunoreactivities in outer hair cells in the PBM group compared with the non-treatment group. However, immunofluorescent image analysis for NF-κB, an upstream protein of inducible nitric oxide synthase, revealed greater activation in the PBM group compared with the naïve and non-treatment groups. Western blot analysis for NF-κB also showed stronger activation in the cochlear tissues in the PBM group compared with the naïve and non-treatment groups (p<0.01, each). These data suggest that PBM activates NF-κB to induce protection against inducible nitric oxide synthase-triggered oxidative stress and caspase-3-mediated apoptosis that occur following noise-induced hearing loss.
Collapse
Affiliation(s)
- Atsushi Tamura
- Department of Otolaryngology - Head and Neck Surgery, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-0042, Japan.
| | - Takeshi Matsunobu
- Department of Otolaryngology - Head and Neck Surgery, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-0042, Japan
| | - Risa Tamura
- Department of Physiology, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-0042, Japan
| | - Satoko Kawauchi
- Division of Bioinformation and Therapeutic Systems, National Defense Medical College Research Institute, 3-2 Namiki, Tokorozawa, Saitama 359-0042, Japan
| | - Shunichi Sato
- Division of Bioinformation and Therapeutic Systems, National Defense Medical College Research Institute, 3-2 Namiki, Tokorozawa, Saitama 359-0042, Japan
| | - Akihiro Shiotani
- Department of Otolaryngology - Head and Neck Surgery, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-0042, Japan
| |
Collapse
|
8
|
Lasisi TJ, Lasisi AO. Evaluation of serum antioxidants in age-related hearing loss. Aging Clin Exp Res 2015; 27:265-9. [PMID: 25362621 DOI: 10.1007/s40520-014-0282-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Accepted: 10/28/2014] [Indexed: 01/10/2023]
Abstract
BACKGROUND Age-related hearing loss (ARHL) has been linked to the shift in the pro-oxidant/antioxidant ratio. Our objectives were to assess serum levels of retinol and zinc among the elderly individuals and to correlate the levels with hearing threshold. METHODS Prospective study of apparently healthy individuals aged ≥60 years of age. Participants had complete clinical history, physical examination and pure tone average conducted. Blood samples were collected for determination of serum levels of retinol and zinc. Mann-Whitney U test was used to compare retinol and zinc values. Pearson's correlation test was used to determine the relationship between hearing threshold and serum levels of retinol and zinc. RESULTS Among 126 elderly participants with mean age 67 ± 2.7 years; the mean pure tone average for air conduction was 29.3 ± 1.6 dBHL while the mean bone conduction was 36.5 ± 1.8 dBHL. The median values of serum retinol and zinc levels in the elderly participants who had hearing loss in the speech frequencies were 52 and 83.3 μg/L, respectively, while among participants with normal hearing threshold, values were 50 and 89.9 μg/L, respectively (p = 0.59 and 0.99, respectively). For the high frequencies, the median value of serum retinol and zinc levels among the elderly participants with normal hearing threshold was 70.3 and 99.9 μg/L, while among those with hearing loss, it was 46.9 and 83.2 μg/L, respectively (p = 0.000 and 0.005, respectively). CONCLUSION Serum retinol and zinc levels were significantly lower among elderly with hearing loss involving the high frequencies. This is added evidence to extant literature on the possible role of antioxidants in the development of ARHL and suggests further study on the effect of antioxidants supplementation in the control of ARHL which is presently controversial and inconclusive.
Collapse
Affiliation(s)
- Taye Jemilat Lasisi
- Departments of Physiology and Oral Pathology, College of Medicine, University of Ibadan, P. O. Box 22040, Ibadan, Nigeria,
| | | |
Collapse
|
9
|
Tamura A, Matsunobu T, Mizutari K, Niwa K, Kurioka T, Kawauchi S, Satoh S, Hiroi S, Satoh Y, Nibuya M, Tamura R, Shiotani A. Low-level laser therapy for prevention of noise-induced hearing loss in rats. Neurosci Lett 2015; 595:81-6. [PMID: 25797186 DOI: 10.1016/j.neulet.2015.03.031] [Citation(s) in RCA: 258] [Impact Index Per Article: 28.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Revised: 01/28/2015] [Accepted: 03/17/2015] [Indexed: 11/25/2022]
Abstract
Noninvasive low-level laser therapy (LLLT) is neuroprotective, but the mechanism of this effect is not fully understood. In this study, the use of LLLT as a novel treatment for noise-induced hearing loss (NIHL) is investigated. Sprague-Dawley rats were exposed to intense noise and their right ears were irradiated with an 808nm diode laser at an output power density of 110 or 165mW/cm(2) for a 30min period for 5 consecutive days. Measurement of the auditory brainstem response revealed an accelerated recovery of auditory function in the groups treated with LLLT compared with the non-treatment group at days 2, 4, 7 and 14 after noise exposure. Morphological observations also revealed a significantly higher outer hair cell survival rate in the LLLT groups. Immunohistochemical analyses for inducible nitric oxide synthase (iNOS) and cleaved caspase-3 were used to examine oxidative stress and apoptosis. Strong immunoreactivities were observed in the inner ear tissues of the non-treatment group, whereas these signals were decreased in the LLLT group at 165mW/cm(2) power density. Our findings suggest that LLLT has cytoprotective effects against NIHL via the inhibition of iNOS expression and apoptosis.
Collapse
Affiliation(s)
- Atsushi Tamura
- Department of Otolaryngology-Head and Neck Surgery, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-0042, Japan
| | - Takeshi Matsunobu
- Department of Otolaryngology-Head and Neck Surgery, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-0042, Japan.
| | - Kunio Mizutari
- Department of Otolaryngology-Head and Neck Surgery, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-0042, Japan
| | - Katsuki Niwa
- Department of Otolaryngology-Head and Neck Surgery, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-0042, Japan
| | - Takaomi Kurioka
- Department of Otolaryngology-Head and Neck Surgery, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-0042, Japan
| | - Satoko Kawauchi
- Division of Biomedical Information Sciences, National Defense Medical College Research Institute, 3-2 Namiki, Tokorozawa, Saitama 359-0042, Japan
| | - Shunichi Satoh
- Division of Biomedical Information Sciences, National Defense Medical College Research Institute, 3-2 Namiki, Tokorozawa, Saitama 359-0042, Japan
| | - Sadayuki Hiroi
- Department of Pathology and Laboratory Medicine, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-0042, Japan
| | - Yasushi Satoh
- Department of Anesthesiology, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-0042, Japan
| | - Masashi Nibuya
- Department of Psychiatry, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-0042, Japan
| | - Risa Tamura
- Department of Physiology, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-0042, Japan
| | - Akihiro Shiotani
- Department of Otolaryngology-Head and Neck Surgery, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-0042, Japan
| |
Collapse
|
10
|
Ren HM, Ren J, Liu W. Recognition and control of the progression of age-related hearing loss. Rejuvenation Res 2014; 16:475-86. [PMID: 23915327 DOI: 10.1089/rej.2013.1435] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Recent breakthroughs have provided notable insights into both the pathogenesis and therapeutic strategies for age-related hearing loss (ARHL). Simultaneously, these breakthroughs enhance our knowledge about this neurodegenerative disease and raise the question of whether the disorder is preventable or even treatable. Discoveries relating to ARHL have revealed a unique link between ARHL and the underlying pathologies. Therefore, we need to better understand the pathogenesis or the mechanism of ARHL and learn how to take full advantage of various therapeutic strategies to prevent the progression of ARHL.
Collapse
Affiliation(s)
- Hong Miao Ren
- Department of Otolaryngology Head and Neck Surgery, the Second Xiangya Hospital, Central South University , Changsha, Hunan, P.R. China
| | | | | |
Collapse
|
11
|
Kim SJ, Lee JH, Kim BS, So HS, Park R, Myung NY, Um JY, Hong SH. (-)-Epigallocatechin-3-gallate protects against NO-induced ototoxicity through the regulation of caspase- 1, caspase-3, and NF-κB activation. PLoS One 2012; 7:e43967. [PMID: 23028481 PMCID: PMC3461011 DOI: 10.1371/journal.pone.0043967] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2011] [Accepted: 07/30/2012] [Indexed: 12/16/2022] Open
Abstract
Excessive nitric oxide (NO) production is toxic to the cochlea and induces hearing loss. However, the mechanism through which NO induces ototoxicity has not been completely understood. The aim of this study was to gain further insight into the mechanism mediating NO-induced toxicity in auditory HEI-OC1 cells and in ex vivo analysis. We also elucidated whether and how epigallocatechin-3-gallate (EGCG), the main component of green tea polyphenols, regulates NO-induced auditory cell damage. To investigate NO-mediated ototoxicity, S-nitroso-N-acetylpenicillamine (SNAP) was used as an NO donor. SNAP was cytotoxic, generating reactive oxygen species, releasing cytochrome c, and activating caspase-3 in auditory cells. NO-induced ototoxicity also mediated the nuclear factor (NF)-κB/caspase-1 pathway. Furthermore, SNAP destroyed the orderly arrangement of the 3 outer rows of hair cells in the basal, middle, and apical turns of the organ of Corti from the cochlea of Sprague-Dawley rats at postnatal day 2. However, EGCG counteracted this ototoxicity by suppressing the activation of caspase-3/NF-κB and preventing the destruction of hair cell arrays in the organ of Corti. These findings may lead to the development of a model for pharmacological mechanism of EGCG and potential therapies against ototoxicity.
Collapse
Affiliation(s)
- Su-Jin Kim
- Department of Cosmeceutical Science, Daegu Hanny University, Kyungsan, Gyeoungbuk, Republic of Korea
| | - Jeong-Han Lee
- Center for Metabolic Function Regulation, Wonkwang University, Iksan, Republic of Korea
| | - Beom-Su Kim
- Wonkwang Bone Regeneration Research Institute, Wonkwang University, Iksan, Jeonbuk, Republic of Korea
| | - Hong-Seob So
- Center for Metabolic Function Regulation, Wonkwang University, Iksan, Republic of Korea
| | - Raekil Park
- Center for Metabolic Function Regulation, Wonkwang University, Iksan, Republic of Korea
| | - Noh-Yil Myung
- Center for Metabolic Function Regulation, Wonkwang University, Iksan, Republic of Korea
| | - Jae-Young Um
- College of Oriental Medicine, Kyung Hee University, Seoul, Republic of Korea
| | - Seung-Heon Hong
- Center for Metabolic Function Regulation, Wonkwang University, Iksan, Republic of Korea
| |
Collapse
|
12
|
Park HY, Lee MH, Kang SU, Hwang HS, Park K, Choung YH, Kim CH. Nitric oxide mediates TNF-α-induced apoptosis in the auditory cell line. Laryngoscope 2012; 122:2256-64. [PMID: 22815072 DOI: 10.1002/lary.23444] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Revised: 03/30/2012] [Accepted: 04/26/2012] [Indexed: 12/15/2022]
Abstract
OBJECTIVES/HYPOTHESIS Tumor necrosis factor-alpha (TNF-α) is released in a variety of pathological states in the inner ear. Inducible nitric oxide synthase (iNOS) can be induced by cytokines and other inflammatory factors, and is generally thought to be associated with inflammation and other pathological processes in the cochlea. The purpose of the present study was to reveal that TNF-α could induce apoptosis in the auditory cell line and to investigate the role of nitric oxide (NO) in TNF-α-induced auditory cell death. STUDY DESIGN Experimental study. METHODS UB-OC1 cells and zebrafish were exposed to TNF-α. Flow cytometry, terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-biotin nick end labeling (TUNEL) assay, assay of mitochondrial membrane potential (MMP), and electron microscopy were used to show that TNF-α could induce apoptosis. Western blot was used to measure iNOS expression and mitogen-activated protein kinase pathway. RESULTS Flow cytometric analysis, TUNEL assay, MMP, and electron microscopy all demonstrated that TNF-α could induce apoptosis in UB-OC1 cells. TNF-α significantly increased NO generation and iNOS expression. Pretreatment with iNOS blocker NG-methyl-L-arginine (NMA) attenuated TNF-α-induced cell death and caspase-3 activation. Also, TNF-α treatment increased p-p38 and p-ERK, and pretreatment of NMA reduced this increased expression of p-p38 and p-ERK. CONCLUSIONS TNF-α can induce apoptosis in the auditory cell line, and NO production in response to TNF-α is essential for apoptosis.
Collapse
Affiliation(s)
- Hun Yi Park
- Department of OtolaryngologyAjou University School of Medicine, Suwon, South Korea
| | | | | | | | | | | | | |
Collapse
|
13
|
Heinrich UR, Helling K. Nitric oxide--a versatile key player in cochlear function and hearing disorders. Nitric Oxide 2012; 27:106-16. [PMID: 22659013 DOI: 10.1016/j.niox.2012.05.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2012] [Revised: 05/10/2012] [Accepted: 05/24/2012] [Indexed: 12/13/2022]
Abstract
Nitric oxide (NO) is a signaling molecule which can generally be formed by three nitric oxide synthases (NOS). Two of them, the endothelial nitric oxide synthase (eNOS) and the neural nitric oxide synthase (nNOS), are calcium/calmodulin-dependent and constitutively expressed in many cell types. Both isoforms are found in the vertebrate cochlea. The inducible nitric oxide synthase (iNOS) is independent of calcium and normally not detectable in the un-stimulated cochlea. In the inner ear, as in other tissues, NO was identified as a multitask molecule involved in various processes such as neurotransmission and neuromodulation. In addition, increasing evidence demonstrates that the NO-dependent processes of cell protection or, alternatively, cell destruction seem to depend, among other things, on changes in the local cochlear NO-concentration. These alterations can occur at the cellular level or within a distinct cell population both leading to an NO-imbalance within the hearing organ. This dysfunction can result in hearing loss or even in deafness. In cases of cochlear malfunction, regulatory systems such as the gap junction system, the blood vessels or the synaptic region might be affected temporarily or permanently by an altered NO-level. This review discusses potential cellular mechanisms how NO might contribute to different forms of hearing disorders. Approaches of NO-reduction are evaluated and the transfer of results obtained from experimental animal models to human medication is discussed.
Collapse
Affiliation(s)
- Ulf-Rüdiger Heinrich
- Department of Otorhinolaryngology, Head and Neck Surgery, University Medical Center of The Johannes Gutenberg-University Mainz, Germany.
| | | |
Collapse
|
14
|
Xin Y, Zhang Z, Yu P, Ma F, Mao L. In vivo electrochemical recording of continuous change of magnesium in medial vestibular nucleus following vertigo induced by ice water vestibular stimulation. Sci China Chem 2012. [DOI: 10.1007/s11426-012-4567-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
|
15
|
Lasisi AO, Fehintola FA. Correlation between plasma levels of radical scavengers and hearing threshold among elderly subjects with age-related hearing loss. Acta Otolaryngol 2011; 131:1160-4. [PMID: 21970786 DOI: 10.3109/00016489.2010.549840] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
CONCLUSION Low plasma melatonin is significant in the development of high frequency hearing loss (HL) among the elderly. OBJECTIVE To determine the correlation between hearing threshold and the plasma melatonin and ascorbic acid (vitamin C). METHODS This was a cross-sectional study involving 126 apparently healthy elderly subjects, 59 males and 67 females, aged >60 years. Subjects underwent pure tone audiometry and plasma melatonin and vitamin C were assayed using high-performance liquid chromatography. RESULTS The mean ± SD of plasma melatonin among the subjects with normal hearing (NH) (0-30 dB) and those with HL in the speech frequencies was 18.3 ± 3.6 μg/L and 16.4 ± 4.7 μg/L, respectively. In the high frequencies the values were 17.7 ± 6.2 μg/L and 13.1 ± 6.4 μg/L for NH and HL, respectively. For vitamin C, the mean ± SD among subjects with NH and those with HL in the speech frequencies were 1.2 ± 0.2 μg/L and 1.0 ± 0.1 μg/L, respectively. In the high frequencies, the values were 1.0 ± 0.2 μg/L and 0.9 ± 0.3 μg/L for NH and HL, respectively. Among subjects with high frequency HL, Spearman's correlation revealed significant correlation between increasing hearing threshold and melatonin (correlation coefficient = -0.30, p = 0.01), but not for vitamin C (correlation coefficient = -0.12, p = 0.22). Linear regression, adjusting for age, still revealed significant correlation between the melatonin (correlation coefficient = -0.03, p = 0.00) and hearing threshold in the high frequencies.
Collapse
Affiliation(s)
- Akeem Olawale Lasisi
- Department of Otorhinolaryngology, College of Medicine, University of Ibadan, Ibadan, Nigeria
| | | |
Collapse
|
16
|
|
17
|
Harada N. Role of nitric oxide on purinergic signalling in the cochlea. Purinergic Signal 2010; 6:211-20. [PMID: 20806013 DOI: 10.1007/s11302-010-9186-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2009] [Accepted: 05/17/2010] [Indexed: 11/30/2022] Open
Abstract
In the inner ear, there is considerable evidence that extracellular adenosine 5'-triphosphate (ATP) plays an important role in auditory neurotransmission as a neurotransmitter or a neuromodulator, although the potential role of adenosine signalling in the modulation of auditory neurotransmission has also been reported. The activation of ligand-gated ionotropic P2X receptors and G protein-coupled metabotropic P2Y receptors has been reported to induce an increase of intracellular Ca(2+) concentration ([Ca(2+)](i)) in inner hair cells (IHCs), outer hair cells (OHCs), spiral ganglion neurons (SGNs), and supporting cells in the cochlea. ATP may participate in auditory neurotransmission by modulating [Ca(2+)](i) in the cochlear cells. Recent studies showed that extracellular ATP induced nitric oxide (NO) production in IHCs, OHCs, and SGNs, which affects the ATP-induced Ca(2+) response via the NO-cGMP-PKG pathway in those cells by a feedback mechanism. A cross-talk between NO and ATP may therefore exist in the auditory signal transduction. In the present article, I review the role of NO on the ATP-induced Ca(2+) signalling in IHCs and OHCs. I also consider the possible role of NO in the ATP-induced Ca(2+) signalling in SGNs and supporting cells.
Collapse
Affiliation(s)
- Narinobu Harada
- Harada Ear Institute, Tomoi 2-34-27, Higashiosaka, Osaka, 577-0816 Japan
| |
Collapse
|
18
|
Takumida M, Anniko M. Radical scavengers for elderly patients with age-related hearing loss. Acta Otolaryngol 2009; 129:36-44. [PMID: 18607930 DOI: 10.1080/00016480802008215] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
CONCLUSION The results of this study suggest that treatment with radical scavengers has the potential to become an effective new therapy for age-related hearing loss. OBJECTIVE To assess the efficacy of treatment with radical scavengers for age-related hearing loss. SUBJECTS AND METHODS Rebamipide (300 mg/day), alpha-lipoic acid (60 mg/day), and vitamin C (600 mg/day) were given orally for at least 8 weeks to 46 elderly patients with age-related hearing loss. RESULTS Hearing levels after treatment were significantly improved at all frequencies.
Collapse
|
19
|
Change of extracellular ascorbic acid in the brain cortex following ice water vestibular stimulation: an on-line electrochemical detection coupled with in vivo microdialysis sampling for guinea pigs. Chin Med J (Engl) 2008. [DOI: 10.1097/00029330-200806020-00016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
|
20
|
Halmos G, Horváth T, Polony G, Fekete Á, Kittel A, Vizi E, van der Laan B, Zelles T, Lendvai B. The role of N-methyl-d-aspartate receptors and nitric oxide in cochlear dopamine release. Neuroscience 2008; 154:796-803. [DOI: 10.1016/j.neuroscience.2008.03.071] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2007] [Revised: 03/27/2008] [Accepted: 03/27/2008] [Indexed: 11/26/2022]
|
21
|
Liu HY, Chi FL, Gao WY. Taurine attenuates aminoglycoside ototoxicity by inhibiting inducible nitric oxide synthase expression in the cochlea. Neuroreport 2008; 19:117-20. [DOI: 10.1097/wnr.0b013e3282f3b0ec] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
22
|
Takeda-Nakazawa H, Harada N, Shen J, Kubo N, Zenner HP, Yamashita T. Hyposmotic stimulation-induced nitric oxide production in outer hair cells of the guinea pig cochlea. Hear Res 2007; 230:93-104. [PMID: 17722255 DOI: 10.1016/j.heares.2007.05.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Nitric oxide (NO) production during hyposmotic stimulation in outer hair cells (OHCs) of the guinea pig cochlea was investigated using the NO sensitive dye DAF-2. Simultaneous measurement of the cell length and NO production showed rapid hyposmotic-induced cell swelling to precede NO production in OHCs. Hyposmotic stimulation failed to induce NO production in the Ca2+-free solution. L-NG-nitroarginine methyl ester (L-NAME), a non-specific NO synthase inhibitor and gadolinium, a stretch-activated channel blocker inhibited the hyposmotic stimulation-induced NO production whereas suramin, a P2 receptor antagonist did not. S-nitroso-N-acetylpenicillamine (SNAP), a NO donor inhibited the hyposmotic stimulation-induced increase in the intracellular Ca2+ concentrations ([Ca2+]i) while L-NAME enhanced it. 1H-[1,2,4]oxadiazole[4,3a]quinoxalin-1-one, an inhibitor of guanylate cyclase and KT5823, an inhibitor of cGMP-dependent protein kinase (PKG) mimicked effects of L-NAME on the Ca2+ response. Transient receptor potential vanilloid 4 (TRPV4), an osmo- and mechanosensitive channel was expressed in the OHCs by means of immunohistochemistry. 4alpha-phorbol 12,13-didecanoate, a TRPV4 synthetic activator, induced NO production in OHCs. These results suggest that hyposmotic stimulation can induce NO production by the [Ca2+]i increase, which is presumably mediated by the activation of TRPV4 in OHCs. NO conversely inhibits the Ca2+ response via the NO-cGMP-PKG pathway by a feedback mechanism.
Collapse
Affiliation(s)
- Hiroko Takeda-Nakazawa
- Hearing Research Laboratory, Department of Otolaryngology, Kansai Medical University, Fumizonocho 10-15, Moriguchi, Osaka 570-8507, Japan
| | | | | | | | | | | |
Collapse
|
23
|
Takeda-Nakazawa H, Harada N, Shen J, Kubo N, Zenner HP, Yamashita T. Hyposmotic stimulation-induced nitric oxide production in outer hair cells of the guinea pig cochlea. Hear Res 2006; 227:59-70. [PMID: 17092670 DOI: 10.1016/j.heares.2006.09.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2006] [Revised: 05/06/2006] [Accepted: 09/24/2006] [Indexed: 10/23/2022]
Abstract
Nitric oxide (NO) production during hyposmotic stimulation in outer hair cells (OHCs) of the guinea pig cochlea was investigated using the NO sensitive dye DAF-2. Simultaneous measurement of the cell length and NO production showed rapid hyposmotic-induced cell swelling to precede NO production in OHCs. Hyposmotic stimulation failed to induce NO production in the Ca(2+)-free solution. L-N(G)-nitroarginine methyl ester (L-NAME), a non-specific NO synthase inhibitor and gadolinium, a stretch-activated channel blocker inhibited the hyposmotic stimulation-induced NO production whereas suramin, a P2 receptor antagonist did not. S-nitroso-N-acetylpenicillamine (SNAP), a NO donor inhibited the hyposmotic stimulation-induced increase in the intracellular Ca(2+) concentrations ([Ca(2+)](i)) while L-NAME enhanced it. 1H-[1,2,4]oxadiazole[4,3a]quinoxalin-1-one, an inhibitor of guanylate cyclase and KT5823, an inhibitor of cGMP-dependent protein kinase (PKG) mimicked effects of L-NAME on the Ca(2+) response. Transient receptor potential vanilloid 4 (TRPV4), an osmo- and mechanosensitive channel was expressed in the OHCs by means of immunohistochemistry. 4alpha-phorbol 12,13-didecanoate, a TRPV4 synthetic activator, induced NO production in OHCs. These results suggest that hyposmotic stimulation can induce NO production by the [Ca(2+)](i) increase, which is presumably mediated by the activation of TRPV4 in OHCs. NO conversely inhibits the Ca(2+) response via the NO-cGMP-PKG pathway by a feedback mechanism.
Collapse
Affiliation(s)
- Hiroko Takeda-Nakazawa
- Hearing Research Laboratory, Department of Otolaryngology, Kansai Medical University, Fumizonocho 10-15, Moriguchi, Osaka 570-8507, Japan
| | | | | | | | | | | |
Collapse
|
24
|
Shen J, Harada N, Nakazawa H, Kaneko T, Izumikawa M, Yamashita T. Role of nitric oxide on ATP-induced Ca2+ signaling in outer hair cells of the guinea pig cochlea. Brain Res 2006; 1081:101-12. [PMID: 16500627 DOI: 10.1016/j.brainres.2005.12.129] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2005] [Revised: 12/20/2005] [Accepted: 12/27/2005] [Indexed: 10/25/2022]
Abstract
Recently, a negative feedback effect of nitric oxide (NO) on the adenosine 5'-triphosphate (ATP)-induced Ca2+ response has been described in cochlear inner hair cells. We here investigated the role of NO on the ATP-induced Ca2+ response in outer hair cells (OHCs) of the guinea pig cochlea using the NO-sensitive dye DAF-2 and Ca2+ -sensitive dye fura-2. Extracellular ATP induced NO production in OHCs, which was inhibited by L-NG-nitroarginine methyl ester (L-NAME), a non-specific NO synthase (NOS) inhibitor, and suramin, a P2 receptor antagonist. ATP failed to induce NO production in the Ca2+ -free solution. S-nitroso-N-acetylpenicillamine (SNAP), a NO donor, enhanced the ATP-induced increase of the intracellular Ca2+ concentrations ([Ca2+]i), while L-NAME inhibited it. SNAP accelerated ATP-induced Mn2+ quenching in fura-2 fluorescence, while L-NAME suppressed it. 8-Bromoguanosine-cGMP, a membrane permeable analog of cGMP, mimicked the effects of SNAP. 1H-[1,2,4]oxadiazole[4,3-a] quinoxalin-1-one, an inhibitor of guanylate cyclase and KT5823, an inhibitor of cGMP-dependent protein kinase inhibited the ATP-induced [Ca2+]i increase. Selective neuronal NOS inhibitors, namely either 7-nitro-indazole or 1-(2-trifluoromethylphenyl) imidazole, mimicked the effects of L-NAME regarding both ATP-induced Ca2+ response and NO production. Immunofluorescent staining of neuronal nitric oxide synthase (nNOS) in isolated OHCs showed the localization of nNOS in the apical region of OHCs. These results suggest that the ATP-induced Ca2+ influx via a direct action of P2X receptors may be the principal source for nNOS activity in the apical region of OHCs. Thereafter, NO can be produced while conversely enhancing the Ca2+ influx via the NO-cGMP-PKG pathway by a feedback mechanism.
Collapse
Affiliation(s)
- Jing Shen
- Hearing Research Laboratory, Department of Otolaryngology, Kansai Medical University, Fumizonocho 10-15, Moriguchi, Osaka 570-8507, Japan
| | | | | | | | | | | |
Collapse
|
25
|
Vega R, Ortega A, Almanza A, Soto E. Nitric oxide in the amphibian (Ambystoma tigrinum) lateral line. Neurosci Lett 2006; 393:65-9. [PMID: 16225991 DOI: 10.1016/j.neulet.2005.09.041] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2005] [Revised: 08/26/2005] [Accepted: 09/16/2005] [Indexed: 10/25/2022]
Abstract
Nicotinamide adenine dinucleotide phosphate reduced-diaphorase (NADPH-d) histochemistry was investigated in the axolotl (Ambystoma tigrinum) lateral line. Hair cells of neuromast organs of the head skin and neurons of the postotic ganglia showed a significant NADPH-d reaction. Multiunit recording of neuromast afferent activity was also performed. Nitric oxide synthase inhibitor N omega-nitro-L-arginine methyl ester (L-NAME) produced an initial slight excitation followed by a significant inhibition of the resting discharge of neuromast afferent neurons. In contrast N(G)-nitro-L-arginine (L-NOARG) produced non-significant actions on the afferent neurons discharge. These findings suggest that afferent neurons and hair cells of the lateral line produce nitric oxide that plays an active role in the mechanisms sustaining basal spike discharge in afferent neurons.
Collapse
Affiliation(s)
- Rosario Vega
- Instituto de Fisiología, Universidad Autónoma de Puebla, Apartado Postal 406, Pue. CP 72000, México.
| | | | | | | |
Collapse
|
26
|
Takumida M, Anniko M. Protective effect of edaravone against the ototoxicity of Pseudomonas aeruginosa exotoxin A. Acta Otolaryngol 2006; 126:15-9. [PMID: 16308249 DOI: 10.1080/00016480510038563] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
CONCLUSION Our findings suggest that edaravone can protect against cochlear damage caused by Pseudomonas aeruginosa exotoxin A (PaExoA). OBJECTIVE To analyze the protective effect of a free radical scavenger, edaravone, against the ototoxicity resulting from exposure of the middle ear to PaExoA. MATERIAL AND METHODS In nine groups of albino rats the following solutions were instilled either via the tympanic membrane into the round window niche [intratympanically (i.t.)] or intravenously (i.v.): edaravone (i.v.); edaravone (i.t.); PaExoA (i.t.) + edaravone (i.t.; simultaneously); PaExoA (i.t.) + edaravone (i.t.; 1 h after); PaExoA (i.t.) + edaravone (i.t.; 24 h after); PaExoA (i.t.) + edaravone (i.v.; simultaneously); PaExoA (i.t.) + edaravone (i.v.; 1 h after); PaExoA (i.t.) + edaravone (i.v.; 24 h after); PaExoA (i.t.) + saline (i.v.). Frequency-specific (2-20 kHz) auditory brainstem responses were measured to determine hearing thresholds before and 2, 5 and 10 days after instillation. RESULTS PaExoA had penetrated from the middle ear into the cochlea and caused hearing loss. This impairment was blocked by intratympanic injection of edaravone when given simultaneously or 1 h after the first instillation of PaExoA, or by intravenous injection of edaravone when given simultaneously. There were significant differences in protective effect between the intratympanic and intravenous routes.
Collapse
Affiliation(s)
- Masaya Takumida
- Department of Otolaryngology, Faculty of Medicine, Hiroshima University, Minamiku, Hiroshima, Japan.
| | | |
Collapse
|
27
|
Abstract
CONCLUSION The results of this study suggest that treatment with radical scavengers has the potential to become an effective new therapy for presbyacusis. OBJECTIVE To assess the efficacy of treatment with the radical scavengers rebamipide and vitamin C for presbyacusis. MATERIAL AND METHODS Rebamipide (300 mg/day) and vitamin C (600 mg/day) were taken orally for at least 8 weeks by 23 patients with presbyacusis. RESULTS Hearing levels after treatment were significantly improved at 125, 250, 500 and 8000 Hz but unchanged at 1000, 2000 and 4000 Hz.
Collapse
Affiliation(s)
- Masaya Takumida
- Department of Otolaryngology, Hiroshima University School of Medicine, Hiroshima, Japan.
| | | |
Collapse
|
28
|
Shen J, Harada N, Nakazawa H, Yamashita T. Involvement of the nitric oxide-cyclic GMP pathway and neuronal nitric oxide synthase in ATP-induced Ca2+ signalling in cochlear inner hair cells. Eur J Neurosci 2005; 21:2912-22. [PMID: 15978003 DOI: 10.1111/j.1460-9568.2005.04135.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We recently demonstrated that extracellular adenosine 5'-triphosphate (ATP) induced nitric oxide (NO) production in the inner hair cells (IHCs) of the guinea pig cochlea, which inhibited the ATP-induced increase in the intracellular Ca(2+) concentrations ([Ca(2+)](i)) by a feedback mechanism [Shen, J., Harada, N. & Yamashita, T. (2003) Neurosci. Lett., 337, 135-138]. We herein investigated the role of the NO-cGMP pathway and neuronal NO synthase (nNOS) in the ATP-induced Ca(2+) signalling in IHCs using the Ca(2+)-sensitive dye fura-2 and the NO-sensitive dye DAF-2. Fura-2 fluorescence-quenching experiments with Mn(2+) showed that ATP triggered a Mn(2+) influx. L-N(G)-nitroarginine methyl ester (L-NAME), a nonspecific NOS inhibitor, accelerated the ATP-induced Mn(2+) influx while S-nitroso-N-acetylpenicillamine (SNAP), a NO donor, suppressed it. 1H-[1,2,4]oxadiazole[4,3-a] quinoxalin-1-one, an inhibitor of guanylate cyclase, and KT5823, an inhibitor of cGMP-dependent protein kinase, enhanced the ATP-induced [Ca(2+)](i) increase. 8-Bromoguanosine-cGMP, a membrane-permeant analogue of cGMP mimicked the effects of SNAP. Moreover, the effects of 7-nitroindazole, a selective nNOS inhibitor, mimicked the effects of L-NAME regarding both the enhancement of the ATP-induced Ca(2+) response and the attenuation of NO production. Immunofluorescent staining of nNOS using a single IHC revealed that nNOS was distributed throughout the IHCs, but enriched in the apical region of the IHCs as shown by intense staining. In conclusion, the ATP-induced Ca(2+) influx may be the principal source for nNOS activity, which may interact with P2X receptors in the apical region of IHCs. Thereafter, NO can be produced and conversely inhibits the Ca(2+) influx via the NO-cGMP-PKG pathway by a feedback mechanism.
Collapse
Affiliation(s)
- Jing Shen
- Hearing Research Laboratory, Department of Otolaryngology, Kansai Medical University, Fumizonocho 10-15, Moriguchi, Osaka 570-8507, Japan
| | | | | | | |
Collapse
|
29
|
Yukawa H, Shen J, Harada N, Cho-Tamaoka H, Yamashita T. Acute effects of glucocorticoids on ATP-induced Ca2+ mobilization and nitric oxide production in cochlear spiral ganglion neurons. Neuroscience 2005; 130:485-96. [PMID: 15664705 DOI: 10.1016/j.neuroscience.2004.09.037] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/17/2004] [Indexed: 11/15/2022]
Abstract
Rapid, non-genomic effects of glucocorticoids on extracellular adenosine 5'-triphosphate (ATP)-induced intracellular Ca(2+) concentration ([Ca(2+)](i)) changes and nitric oxide (NO) production were investigated in type I spiral ganglion neurons (SGNs) of the guinea-pig cochlea using the Ca(2+)-sensitive dye fura-2 and the NO-sensitive dye 4,5-diaminofluorescein (DAF-2). Pretreatment of SGNs with 1 microM dexamethasone for 10 min, a synthetic glucocorticoid hormone, enhanced the ATP-induced [Ca(2+)](i) increase in SGNs. RU 38486, a competitive glucocorticoid receptor antagonist eliminated the effects of dexamethasone on the ATP-induced [Ca(2+)](i) increase in SGNs. These acute effects of dexamethasone were dependent on the presence of extracellular Ca(2+), thereby suggesting that dexamethasone may rapidly enhance the Ca(2+) influx through the activation of ionotropic P2X receptors which may interact with glucocorticoid-mediated membrane receptors. Extracellular ATP increased the intensity of DAF-2 fluorescence, indicating NO production in SGNs. The ATP-induced NO production was mainly due to the Ca(2+) influx through the activation of P2 receptors. S-nitroso-N-acetylpenicillamine, a NO donor, enhanced the ATP-induced [Ca(2+)](i) increase in SGNs while L-N(G)-nitroarginine methyl ester (L-NAME), a NO synthesis inhibitor, inhibited it. Dexamethasone enhanced the ATP-induced NO production in SGNs. The augmentation of dexamethasone on ATP-induced NO production was abolished in the presence of l-NAME. It is concluded that the ATP-induced [Ca(2+)](i) increase induces NO production which enhances a [Ca(2+)](i) increase in SGNs by a positive-feedback mechanism. Dexamethasone enhances the ATP-induced [Ca(2+)](i) increase in SGNs which results in the augmentation of NO production. The present study suggests that NO may play an important role in auditory signal transduction. Our results also indicate that glucocorticoids may rapidly affect auditory neurotransmission due to a novel non-genomic mechanism.
Collapse
Affiliation(s)
- H Yukawa
- Hearing Research Laboratory, Department of Otolaryngology, Kansai Medical University, Fumizono-cho 10-15, Moriguchi, Osaka 570-8507, Japan
| | | | | | | | | |
Collapse
|
30
|
Abstract
Cisplatin is known to cause high-frequency neurosensory hearing loss. While reactive oxygen species have been shown to play a role, reactive nitrogen species have been implicated, but not proven to be involved, in cisplatin ototoxicity. The purpose of the present study was to investigate the role of nitric oxide (*NO) in cisplatin ototoxicity by administering aminoguanidine (AG), a relatively specific inhibitor of inducible nitric oxide synthase (iNOS), in conjunction with cisplatin. Rats were injected with cisplatin, AG, or both. Auditory brainstem evoked responses (ABR) were measured before and 3 days after cisplatin administration. The cochlear tissue was then assayed for *NO and malondialdehyde. Cisplatin alone caused significant ABR threshold shifts at all stimuli tested, whereas AG alone caused no shifts. There was a significant reduction in threshold shift for clicks and 16 kHz tone bursts (but not 32 kHz) when AG was given with cisplatin. The malondialdehyde concentration (but not the *NO concentration) in the AG/cisplatin group was significantly lower than that of the cisplatin group. This suggests that AG reduces cisplatin ototoxicity by directly scavenging hydroxyl radicals. The iNOS pathway may play a role in the generation of free radicals and hearing loss resulting from cisplatin administration, but this conclusion was not supported by our data.
Collapse
Affiliation(s)
- Thomas C Kelly
- Southern Illinois University School of Medicine, Department of Surgery, P.O. Box 19638, Springfield, IL 62794-9653, USA
| | | | | | | |
Collapse
|
31
|
Maetani T, Hakuba N, Taniguchi M, Hyodo J, Shimizu Y, Gyo K. Free radical scavenger protects against inner hair cell loss after cochlear ischemia. Neuroreport 2003; 14:1881-4. [PMID: 14534440 DOI: 10.1097/00001756-200310060-00025] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
We investigated the protective effects of edaravone, a free radical scavenger, against ischemic damage of inner hair cells (IHCs) in gerbils. Cochlear ischemia was induced in the animals by occluding the vertebral arteries bilaterally for 15 min. Edaravone (1 mg/kg, i.v.) or saline was administered 1 h after ischemia. Hearing was assessed by auditory brain response (ABR). In animals treated with saline, the ABR threshold shift was 24.1 dB and there was a 26.5% decrease in the number of IHCs. By contrast, in animals treated with edaravone, the threshold shift was 7.5 dB and only 8.8% of IHCs was lost. These results suggest that edaravone protects against damage to the inner ear following transient ischemia.
Collapse
Affiliation(s)
- Toshiki Maetani
- Department of Otolaryngology, Ehime University School of Medicine, Ehime, Japan
| | | | | | | | | | | |
Collapse
|
32
|
Koga K, Hakuba N, Watanabe F, Shudou M, Nakagawa T, Gyo K. Transient cochlear ischemia causes delayed cell death in the organ of Corti: an experimental study in gerbils. J Comp Neurol 2003; 456:105-11. [PMID: 12509868 DOI: 10.1002/cne.10479] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
To elucidate whether ischemia-reperfusion can cause delayed cell death in the cochlea, the effects of transient cochlear ischemia on hearing and on neuronal structures in the cochlea were studied in Mongolian gerbils. Ischemia was induced by bilaterally occluding the vertebral arteries for 5 minutes in gerbils, which lack posterior cerebral communicating arteries. In gerbils, the labyrinthine arteries are fed solely by the vertebral arteries. Occlusion of the vertebral arteries caused a remarkable increase in the threshold of compound action potentials (CAPs), which recovered over the following day. However, 7 days after the onset of reperfusion, the threshold began to increase again. Morphologic changes in the hair cell stereocilia were revealed by electron microscopy. The number of nuclear collapses was counted in cells stained for DNA and F-actin to evaluate the degree of cell death in the organ of Corti. Changes in spiral ganglion cell (SGC) neuron number were detected, whether or not progressive neuronal death occurred in the SGC. These studies showed that sporadic fusion of hair cells and the disappearance of hair cell stereocilia did not begin until 4 days after ischemia. On subsequent days, the loss of hair cells, especially inner hair cells (IHCs), and the degeneration of SGC neurons became apparent. Ten days after ischemia, the mean percentage cell loss of IHCs was 6.4% in the basal turn, 6.4% in the second turn, and 0.8% in the apical turn, respectively, and the number of SGC neurons had decreased to 89% of preischemic status. These results indicate that transient ischemia causes delayed hearing loss and cell death in the cochlea by day 7 after ischemia.
Collapse
MESH Headings
- Action Potentials
- Animals
- Auditory Threshold
- Cell Death
- Cochlear Diseases/etiology
- Cochlear Diseases/pathology
- Cochlear Diseases/physiopathology
- Disease Models, Animal
- Disease Progression
- Gerbillinae
- Hair Cells, Auditory, Inner/pathology
- Hair Cells, Auditory, Inner/ultrastructure
- Hair Cells, Auditory, Outer/pathology
- Hair Cells, Auditory, Outer/ultrastructure
- Hearing Loss, Sensorineural/diagnosis
- Hearing Loss, Sensorineural/etiology
- Hearing Loss, Sensorineural/physiopathology
- Neurons/pathology
- Organ of Corti/blood supply
- Organ of Corti/pathology
- Organ of Corti/physiopathology
- Reperfusion Injury/complications
- Reperfusion Injury/pathology
- Reperfusion Injury/physiopathology
- Spiral Ganglion/pathology
- Vertebral Artery/physiopathology
Collapse
Affiliation(s)
- Kenichiro Koga
- Department of Otolaryngology, Ehime University School of Medicine, Ehime, 791-0295 Japan.
| | | | | | | | | | | |
Collapse
|