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Meliante LA, Piccotti G, Tanga L, Giammaria S, Manni G, Coco G. Glaucoma, Pseudoexfoliation and Hearing Loss: A Systematic Literature Review. J Clin Med 2024; 13:1379. [PMID: 38592217 PMCID: PMC10931971 DOI: 10.3390/jcm13051379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Revised: 02/18/2024] [Accepted: 02/23/2024] [Indexed: 04/10/2024] Open
Abstract
Purpose: To investigate the relationship between glaucoma, pseudoexfoliation and hearing loss (HL). Methods: A systematic literature search following PRISMA guidelines was conducted using the PubMed, Embase, Scopus and Cochrane databases from 1995 up to 28 August 2023. Results: Thirty studies out of the 520 records screened met the inclusion criteria and were included. Most articles (n = 20) analysed the association between pseudoexfoliation syndrome (XFS) and HL, showing XFS patients to have higher prevalence of sensorineural hearing loss (SNHL) at both speech frequencies (0.25, 0.5, 1 and 2 kHz), and higher frequencies (4 and 8 kHz) compared to controls in most cases. No significant differences in prevalence or level of HL between XFS and pseudoexfoliative glaucoma (XFG) were detected in most studies. Eight articles analysed the relationship between primary open-angle glaucoma (POAG) and HL. Overall, a positive association between the two conditions was highlighted across all studies except for two cases. Similarly, articles focusing on NTG and HL (n = 4) showed a positive association in most cases. The role of autoimmunity and, in particular, the presence of antiphosphatidylserine antibodies (APSA) in patients with NTG and HL suggested an underlying autoimmune or vascular mechanism contributing to their pathogenesis. Only one study analysed the relationship between angle-closure glaucoma (ACG) and HL, showing higher incidence of ACG in patients with SNHL compared to normal hearing controls. Conclusions: Most studies detected an association between XFS and HL as well as POAG/NTG/ACG and HL, suggesting the presence of a similar pathophysiology of neurodegeneration. However, given the strength of the association of XFS with HL, it remains unclear whether the presence of XFG is further associated with SNHL. Further research specifically targeted to assess the correlation between glaucoma, XFS and HL is warranted to provide a more comprehensive understanding of this association.
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Affiliation(s)
- Laura Antonia Meliante
- Department of Clinical Sciences and Translational Medicine, University of Rome Tor Vergata, 00133 Rome, Italy; (L.A.M.); (G.P.); (G.C.)
| | - Giulia Piccotti
- Department of Clinical Sciences and Translational Medicine, University of Rome Tor Vergata, 00133 Rome, Italy; (L.A.M.); (G.P.); (G.C.)
| | - Lucia Tanga
- IRCCS—Fondazione Bietti, 00184 Rome, Italy; (L.T.); (S.G.)
| | - Sara Giammaria
- IRCCS—Fondazione Bietti, 00184 Rome, Italy; (L.T.); (S.G.)
| | - Gianluca Manni
- Department of Clinical Sciences and Translational Medicine, University of Rome Tor Vergata, 00133 Rome, Italy; (L.A.M.); (G.P.); (G.C.)
- IRCCS—Fondazione Bietti, 00184 Rome, Italy; (L.T.); (S.G.)
| | - Giulia Coco
- Department of Clinical Sciences and Translational Medicine, University of Rome Tor Vergata, 00133 Rome, Italy; (L.A.M.); (G.P.); (G.C.)
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Nelson MD, Bennett DM, Lehman ME, Okonji AI. Dizziness, Falls, and Hearing Loss in Adults Living With Sickle Cell Disease. Am J Audiol 2022; 31:1178-1190. [DOI: 10.1044/2022_aja-22-00059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Objective:
The aim of this study was to assess the prevalence of reported dizziness/imbalance, frequency of falls, and hearing loss in adults with sickle cell disease (SCD) and determine the relationship of these self-reported problems both during and in the absence of an SCD crisis. Also, the impact of educational level and health insurance on seeking treatment services, as well as the relationship of falls to stroke, legal blindness, and other orthopedic problems, was assessed. Interrupted blood flow to shared vestibular and auditory arteries supports the notion of increased likelihood of balance deficits and increased falls in this population.
Design:
A cross-sectional survey study design was used. Adults living with SCD responded to a questionnaire that was distributed online and through traditional mail.
Study Sample:
Adults living with SCD (
N
= 135) participated in the study.
Results:
Responses revealed 70% of participants with SCD experienced dizziness/imbalance and 23% reported hearing loss. Furthermore, 33% of participants reported falling one or more times in the last year. The prevalence of dizziness/imbalance, falling, and hearing loss in the respondents with SCD was much higher than that of the general population of the United States. Additionally, for dizziness and falling, the prevalence was higher not only than the national average but also for persons over 65 years of age. A significant association was demonstrated between dizziness/imbalance and hearing loss as well as dizziness/imbalance and falls for adults living with SCD. In fact, participants with self-reported hearing loss were 5.2 times more likely to also report dizziness/imbalance. They were 4.9 times more likely to fall if they also reported dizziness/imbalance. Numbness of the feet was revealed to significantly impact the likelihood of falling in this disease population and should be further studied. Regarding SCD crisis status, dizziness/imbalance and falls were more likely to occur outside of SCD crisis than during a crisis. Furthermore, pain levels were significantly associated with dizziness/imbalance only when respondents were in crisis and not in the absence of a crisis. In crisis, higher pain levels were reported from respondents who also reported dizziness/imbalance than from those who did not report dizziness. No significant relationship was revealed between hearing loss and falls.
Discussion:
These results provide justification for patient and health care provider education regarding appropriate referrals for vestibular/balance assessments and provision of fall prevention strategies. Future studies on balance and SCD are encouraged.
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Chan J, Telang R, Kociszewska D, Thorne PR, Vlajkovic SM. A High-Fat Diet Induces Low-Grade Cochlear Inflammation in CD-1 Mice. Int J Mol Sci 2022; 23:5179. [PMID: 35563572 PMCID: PMC9101486 DOI: 10.3390/ijms23095179] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 05/02/2022] [Accepted: 05/04/2022] [Indexed: 02/04/2023] Open
Abstract
There is growing evidence for a relationship between gut dysbiosis and hearing loss. Inflammatory bowel disease, diet-induced obesity (DIO), and type 2 diabetes have all been linked to hearing loss. Here, we investigated the effect of a chronic high-fat diet (HFD) on the development of inner ear inflammation using a rodent model. Three-week-old CD-1 (Swiss) mice were fed an HFD or a control diet for ten weeks. After ten weeks, mouse cochleae were harvested, and markers of cochlear inflammation were assessed at the protein level using immunohistochemistry and at the gene expression level using quantitative real-time RT-PCR. We identified increased immunoexpression of pro-inflammatory biomarkers in animals on an HFD, including intracellular adhesion molecule 1 (ICAM1), interleukin 6 receptor α (IL6Rα), and toll-like-receptor 2 (TLR2). In addition, increased numbers of ionized calcium-binding adapter molecule 1 (Iba1) positive macrophages were found in the cochlear lateral wall in mice on an HFD. In contrast, gene expression levels of inflammatory markers were not affected by an HFD. The recruitment of macrophages to the cochlea and increased immunoexpression of inflammatory markers in mice fed an HFD provide direct evidence for the association between HFD and cochlear inflammation.
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Affiliation(s)
| | | | | | | | - Srdjan M. Vlajkovic
- Department of Physiology and The Eisdell Moore Centre, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand; (J.C.); (R.T.); (D.K.); (P.R.T.)
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4
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Sonbay Yilmaz ND, Saka C, Alicura Tokgöz S, Çalişkan M, Vuralkan E, Beşalti Ö. Effects of acute hypoxia on auditory pathway of Wistar albino rats. Turk J Med Sci 2020; 50:1580-1584. [PMID: 32777898 PMCID: PMC7605089 DOI: 10.3906/sag-1911-166] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 08/10/2020] [Indexed: 11/17/2022] Open
Abstract
Background/aim Ischemia is insufficient blood flow to provide adequate oxygenation. In the present study, we aimed to show whether acute hypoxia has a critical oxygen value that may lead to the deterioration of cochlear function. Materials and methods Under general anesthesia, prehypoxic signal-to-noise ratios were determined by distortion product otoacoustic emissions (DPOAE). The oxygen saturation (SaO2) values of rats were monitored with an oxygen saturation probe. Rats were injected with an extra dose of anesthetic agent, and SaO2 was reduced. DPOAE values in SaO2 100–90, 90–80, 80–70, and 70–60 posthypoxic values were measured and compared statistically with prehypoxic values. Results At 3000 and 4000 Hz, SaO2 70–60 values measured after the hypoxia were observed to be statistically significantly lower than the values measured before the hypoxia. At 6000 and 8000 Hz, SaO2 80–70 and 70–60 values measured after the hypoxia were observed to be statistically significantly lower than the values measured before the hypoxia. At 10,000 Hz, all of the values measured after the hypoxia were observed to be statistically significantly lower than the values obtained before the hypoxia. Conclusion Many studies have been conducted on the effects of hypoxia on the inner ear. It remains unclear how fluctuations in DPOAE levels affect hearing in clinical trials when the SaO2 starts to decrease. Although hypoxia has been implicated in the etiology of sudden hearing loss and tinnitus, the effects of acute hypoxia on the cochlea are still uncertain. Further studies are needed on this subject.
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Affiliation(s)
| | - Cem Saka
- Department of Ear, Nose, and Throat, Ankara Dışkapı Yıldırım Beyazıt Education and Training Hospital, Ankara, Turkey
| | - Sibel Alicura Tokgöz
- Department of Ear, Nose, and Throat, Ankara Dışkapı Yıldırım Beyazıt Education and Training Hospital, Ankara, Turkey
| | - Murat Çalişkan
- Department of Surgery, Faculty of Veterinary Medicine, Ankara University, Ankara, Turkey
| | - Erkan Vuralkan
- Department of Ear, Nose, and Throat, Medical Park Trabzon Hospital, Trabzon, Turkey
| | - Ömer Beşalti
- Department of Surgery, Faculty of Veterinary Medicine, Ankara University, Ankara, Turkey
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Sahley TL, Anderson DJ, Hammonds MD, Chandu K, Musiek FE. Evidence for a dynorphin-mediated inner ear immune/inflammatory response and glutamate-induced neural excitotoxicity: an updated analysis. J Neurophysiol 2019; 122:1421-1460. [DOI: 10.1152/jn.00595.2018] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Acoustic overstimulation (AOS) is defined as the stressful overexposure to high-intensity sounds. AOS is a precipitating factor that leads to a glutamate (GLU)-induced Type I auditory neural excitotoxicity and an activation of an immune/inflammatory/oxidative stress response within the inner ear, often resulting in cochlear hearing loss. The dendrites of the Type I auditory neural neurons that innervate the inner hair cells (IHCs), and respond to the IHC release of the excitatory neurotransmitter GLU, are themselves directly innervated by the dynorphin (DYN)-bearing axon terminals of the descending brain stem lateral olivocochlear (LOC) system. DYNs are known to increase GLU availability, potentiate GLU excitotoxicity, and induce superoxide production. DYNs also increase the production of proinflammatory cytokines by modulating immune/inflammatory signal transduction pathways. Evidence is provided supporting the possibility that the GLU-mediated Type I auditory neural dendritic swelling, inflammation, excitotoxicity, and cochlear hearing loss that follow AOS may be part of a brain stem-activated, DYN-mediated cascade of inflammatory events subsequent to a LOC release of DYNs into the cochlea. In support of a DYN-mediated cascade of events are established investigations linking DYNs to the immune/inflammatory/excitotoxic response in other neural systems.
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Affiliation(s)
- Tony L. Sahley
- Department of Biological, Geological, and Environmental Sciences, Cleveland State University, Cleveland, Ohio
- School of Health Sciences, Cleveland State University, Cleveland, Ohio
| | - David J. Anderson
- Department of Chemistry, Cleveland State University, Cleveland, Ohio
| | | | - Karthik Chandu
- Department of Chemistry, Cleveland State University, Cleveland, Ohio
| | - Frank E. Musiek
- Department of Speech, Language, and Hearing Sciences, University of Arizona, Tucson, Arizona
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6
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Intratympanic methylprednisolone perfusion as a salvage treatment for profound idiopathic sudden sensorineural hearing loss. The Journal of Laryngology & Otology 2017; 131:404-410. [DOI: 10.1017/s0022215117000548] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
AbstractObjective:This study aimed to examine the effectiveness of intratympanic methylprednisolone perfusion as salvage treatment for profound idiopathic sudden sensorineural hearing loss.Methods:A retrospective clinical study of 97 patients with unilateral profound idiopathic sudden sensorineural hearing loss was performed. In all, 83 patients who received salvage intratympanic methylprednisolone perfusion plus conventional treatment (except for steroids) as the second-line therapy were assigned to the study group, while 14 patients who received conventional treatment alone were assigned to the comparison group.Results:In the study group, treatments in patients with a shorter interval from disease onset to intratympanic methylprednisolone perfusion (up to 15 days) had significantly greater improvements in the overall effective rate and pure tone average compared with patients with a longer interval (over 15 days). For patients with a short interval from disease onset to intratympanic methylprednisolone perfusion, those in the study group had significantly greater improvements in the overall effective rate and pure tone average compared with those in the comparison group. In both the study and comparison groups, hearing improvements were greater at low frequencies than at medium and high frequencies.Conclusion:The interval from disease onset to intratympanic methylprednisolone perfusion was the major factor affecting hearing recovery. Early second-line salvage intratympanic methylprednisolone perfusion significantly improved the degree of hearing recovery in profound idiopathic sudden sensorineural hearing loss patients after failure of systemic steroid treatment.
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7
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Onal M, Elsurer C, Selimoglu N, Yilmaz M, Erdogan E, Bengi Celik J, Kal O, Onal O. Ozone Prevents Cochlear Damage From Ischemia-Reperfusion Injury in Guinea Pigs. Artif Organs 2017; 41:744-752. [DOI: 10.1111/aor.12863] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 07/21/2016] [Accepted: 08/17/2016] [Indexed: 12/14/2022]
Affiliation(s)
- Merih Onal
- Department of Otorhinolaryngology; Konya Educational and Training Hospital
| | - Cagdas Elsurer
- Department of Otolaryngology; Selcuk University Medical Faculty
| | - Nebil Selimoglu
- Department of Plastic Surgery; Konya Educational and Training Hospital
| | | | | | - Jale Bengi Celik
- Department of Anesthesiology and Reanimation; Selcuk University Medical Faculty
| | - Oznur Kal
- Department of Nephrology; Baskent University Medical Faculty; Konya Turkey
| | - Ozkan Onal
- Department of Anesthesiology and Reanimation; Selcuk University Medical Faculty
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8
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Carraro M, Almishaal A, Hillas E, Firpo M, Park A, Harrison RV. Cytomegalovirus (CMV) Infection Causes Degeneration of Cochlear Vasculature and Hearing Loss in a Mouse Model. J Assoc Res Otolaryngol 2016; 18:263-273. [PMID: 27995350 DOI: 10.1007/s10162-016-0606-4] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 11/24/2016] [Indexed: 12/20/2022] Open
Abstract
Cytomegalovirus (CMV) infection is one of the most common causes of congenital hearing loss in children. We have used a murine model of CMV infection to reveal functional and structural cochlear pathogenesis. The cerebral cortex of Balb/c mice (Mus musculus) was inoculated with 2000 pfu (plaque forming units) of murine CMV on postnatal day 3. At 6 weeks of age, cochlear function was monitored using auditory brainstem response (ABR) and distortion product otoacoustic emission (DPOAE) measures. Histological assessment of cochlear vasculature using a corrosion cast technique was made at 8 weeks. Vascular casts of mCMV-damaged cochleas, and those of untreated control animals, were examined using scanning electron microscopy. We find very large variations in the degree of vascular damage in animals given identical viral injections (2000 pfu). The primary lesion caused by CMV infection is to the stria vascularis and to the adjacent spiral limbus capillary network. Capillary beds of the spiral ligament are generally less affected. The initial vascular damage is found in the mid-apical turn and appears to progress to more basal cochlear regions. After viral migration to the inner ear, the stria vascularis is the primary affected structure. We suggest that initial auditory threshold losses may relate to the poor development or maintenance of the endocochlear potential caused by strial dysfunction. Our increased understanding of the pathogenesis of CMV-related hearing loss is important for defining methods for early detection and treatment.
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Affiliation(s)
- Mattia Carraro
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada
- Auditory Science Laboratory, Neuroscience and Mental Health Program, The Hospital for Sick Children, Toronto, ON, Canada
| | - Ali Almishaal
- Department of Communication Sciences and Disorders, University of Utah, Salt Lake City, UT, USA
| | - Elaine Hillas
- Department of Surgery, University of Utah, Salt Lake City, UT, USA
| | - Matthew Firpo
- Department of Surgery, University of Utah, Salt Lake City, UT, USA
| | - Albert Park
- Department of Surgery, University of Utah, Salt Lake City, UT, USA
- Department of Otolaryngology, University of Utah, Salt Lake City, UT, USA
| | - Robert V Harrison
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada.
- Auditory Science Laboratory, Neuroscience and Mental Health Program, The Hospital for Sick Children, Toronto, ON, Canada.
- Department of Otolaryngology, Head and Neck Surgery, University of Toronto, Toronto, ON, Canada.
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9
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Berjis N, Soheilipour S, Musavi A, Hashemi SM. Intratympanic dexamethasone injection vs methylprednisolone for the treatment of refractory sudden sensorineural hearing loss. Adv Biomed Res 2016; 5:111. [PMID: 27403406 PMCID: PMC4926553 DOI: 10.4103/2277-9175.184277] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Accepted: 06/17/2013] [Indexed: 11/15/2022] Open
Abstract
Background: During the past years various drugs have been used for sudden sensorineural hearing loss (SSNHL) treatment including steroids that are shown to be beneficial. Directed delivery of high doses of steroids into the inner ear is suggested for its potential and known as intratympanic steroids therapy (IST). Despite the use of dexamethasone and methylprednisolone as the traditional treatments, there are still debates about the optimal dosage, preferred drug, and the route of administration. Materials and Methods: We performed a randomized clinical trial study in which 50 patients suffering from SSNHL and resistant to standard therapy were employed. Each patient took 0.5 ml methylprednisolone (40 mg/mg) along with bicarbonate or dexamethasone (4 mg/mL) through direct intratympanic injection. This method was performed and scheduled once every 2 days for three times only for the dexamethasone receiving group. Hearing test was carried out and the results were analyzed according to a four-frequency (0.5, 1.0, 2.0, 3.0 kHz) pure tone average (PTA) and Siegel's criteria. Results: According to Siegel's criteria, three out of 25 (12%) dexamethasone receiving patients were healed in 1 and 4 (16%), 9 (32%) were respectively recovered in Siegel's criteria 2, 3, and 9 (32%) showed no recovery. In the group receiving methylprednisolone, recovery was found in 6 (24%), 8 (32%), 7 (28%) patients in the Siegel's criteria 1, 2, 3, respectively, and in 4 (16%) patients no recovery was recorded. In methylprednisolone group, hearing was significantly improved compared to the dexamethasone group (P < 0.05). The general hearing improvement rate was 84% in methylprednisolone receiving patients showing a significantly higher improvement than 64% in the dexamethasone group. Conclusions: Topical intratympanic treatment with methylprednisolone is safe and an effective treatment approach for those SSNHL cases that are refractory to the common therapies by Dexamethasone.
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Affiliation(s)
- Nezamoddin Berjis
- Department of Otorhinolaryngology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Saeed Soheilipour
- Department of Otorhinolaryngology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Alireza Musavi
- Department of Otorhinolaryngology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Seyed Mostafa Hashemi
- Department of Otorhinolaryngology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran
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10
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Rance G, Starr A. Pathophysiological mechanisms and functional hearing consequences of auditory neuropathy. Brain 2015; 138:3141-58. [PMID: 26463676 DOI: 10.1093/brain/awv270] [Citation(s) in RCA: 110] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 08/05/2015] [Indexed: 01/19/2023] Open
Abstract
The effects of inner ear abnormality on audibility have been explored since the early 20th century when sound detection measures were first used to define and quantify 'hearing loss'. The development in the 1970s of objective measures of cochlear hair cell function (cochlear microphonics, otoacoustic emissions, summating potentials) and auditory nerve/brainstem activity (auditory brainstem responses) have made it possible to distinguish both synaptic and auditory nerve disorders from sensory receptor loss. This distinction is critically important when considering aetiology and management. In this review we address the clinical and pathophysiological features of auditory neuropathy that distinguish site(s) of dysfunction. We describe the diagnostic criteria for: (i) presynaptic disorders affecting inner hair cells and ribbon synapses; (ii) postsynaptic disorders affecting unmyelinated auditory nerve dendrites; (iii) postsynaptic disorders affecting auditory ganglion cells and their myelinated axons and dendrites; and (iv) central neural pathway disorders affecting the auditory brainstem. We review data and principles to identify treatment options for affected patients and explore their benefits as a function of site of lesion.
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Affiliation(s)
- Gary Rance
- 1 Department of Audiology and Speech Pathology, The University of Melbourne, 550 Swanston Street, Parkville 3010 Australia
| | - Arnold Starr
- 2 Department of Neurology, The University of California (Irvine), 200 S. Manchester Ave., Suite 206, Orange, CA 92868-4280, USA
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Foster C, Breeze R. The Meniere attack: An ischemia/reperfusion disorder of inner ear sensory tissues. Med Hypotheses 2013; 81:1108-15. [DOI: 10.1016/j.mehy.2013.10.015] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Accepted: 10/11/2013] [Indexed: 01/12/2023]
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12
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Effectiveness of intratympanic dexamethasone for refractory sudden sensorineural hearing loss. Eur Arch Otorhinolaryngol 2013; 271:1431-6. [DOI: 10.1007/s00405-013-2594-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Accepted: 06/05/2013] [Indexed: 10/26/2022]
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13
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O'Hare F, Rance G, McKendrick AM, Crowston JG. Is primary open-angle glaucoma part of a generalized sensory neurodegeneration? A review of the evidence. Clin Exp Ophthalmol 2012; 40:895-905. [DOI: 10.1111/j.1442-9071.2012.02812.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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14
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Ferri E, Frisina A, Fasson AC, Armato E, Spinato G, Amadori M. Intratympanic steroid treatment for idiopathic sudden sensorineural hearing loss after failure of intravenous therapy. ISRN OTOLARYNGOLOGY 2012; 2012:647271. [PMID: 23724270 PMCID: PMC3658561 DOI: 10.5402/2012/647271] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Accepted: 11/14/2011] [Indexed: 11/23/2022]
Abstract
Purpose. The aim of this study is the investigation of the effectiveness of intratympanic steroids therapy (IST) in patients with idiopathic sudden sensorineural hearing loss (ISSHL) who had not responded to intravenous treatment, evaluating the overall hearing recovery and comparing the results with different variables. Materials and Methods. Our study consisted of 55 patients with refractory ISSHL who, at the end of 10 days of therapy with intravenous steroids, had puretone 4-frequency average (PTA) of worse than 30 dB. The patients received 0.5 mL of methylprednisolone by direct intratympanic injection. The procedure was carried out up to 7 times within a 20-days period. Statistical analysis was carried out. Results. Overall 29 patients (52.7%) showed improvement in PTA, 24 (43.8%) had no change in hearing, and 2 (3.5%) worsened. There was a significant statistical correlation between hearing recovery and time to onset of symptoms, severity of hearing loss and frequency of hearing loss. Conclusions. IST is an effective and safe therapy in sudden sensorineural hearing loss cases that are refractory to standard treatment. The earlier IST, the hearing losses less than 90 dB and the involvement of the low frequencies seem to influence positively the hearing recovery.
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Affiliation(s)
- Emanuele Ferri
- Otologic Surgery Unit, Otorhinolaryngology Department ULSS 13, General Hospitals of Dolo and Mirano, Via Mariutto 76, 30035 Mirano, Italy
| | - Antonio Frisina
- Otorhinolaryngology Department, San Bortolo Hospital, Via F. Rodolfi, 37, 36100 Vicenza, Italy
| | - Anna Chiara Fasson
- Otorhinolaryngology Department, San Bortolo Hospital, Via F. Rodolfi, 37, 36100 Vicenza, Italy
| | - Enrico Armato
- Otologic Surgery Unit, Otorhinolaryngology Department ULSS 13, General Hospitals of Dolo and Mirano, Via Mariutto 76, 30035 Mirano, Italy
| | - Giacomo Spinato
- ENT Clinic, Head and Neck Department, University of Trieste, Hospital of Cattinara, Strada di Fiume 447, 34149 Trieste, Italy
| | - Maurizio Amadori
- Otologic Surgery Unit, Otorhinolaryngology Department ULSS 13, General Hospitals of Dolo and Mirano, Via Mariutto 76, 30035 Mirano, Italy
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15
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Attias J, Raveh E, Aizer-Dannon A, Bloch-Mimouni A, Fattal-Valevski A. Auditory System Dysfunction due to Infantile Thiamine Deficiency: Long-Term Auditory Sequelae. ACTA ACUST UNITED AC 2012; 17:309-20. [DOI: 10.1159/000339356] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2011] [Accepted: 04/19/2012] [Indexed: 01/19/2023]
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16
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Witt KM, Bockman CS, Dang HK, Gruber DD, Wangemann P, Scofield MA. Molecular and pharmacological characteristics of the gerbil α(1a)-adrenergic receptor. Hear Res 2011; 283:144-50. [PMID: 22101021 DOI: 10.1016/j.heares.2011.11.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2011] [Revised: 10/25/2011] [Accepted: 11/01/2011] [Indexed: 11/27/2022]
Abstract
The spiral modiolar artery supplies blood and essential nutrients to the cochlea. Our previous functional study indicates the α(1A)-adrenergic receptor subtype mediates vasoconstriction of the gerbil spiral modiolar artery. Although the gerbil cochlea is often used as a model in hearing research, the molecular and pharmacological characteristics of the cloned gerbil α(1a)-adrenergic receptor have not been determined. Thus we cloned, expressed and characterized the gerbil α(1a)-adrenergic receptor and then compared its molecular and pharmacological properties to those of other mammalian α(1a)-adrenergic receptors. The cDNA clone contained 1404 nucleotides, which encoded a 467 amino acid peptide with a deduced sequence having 96.8, 96.4 and 91.6% identity to rat, mouse and human α(1a)-receptors, respectively. We transiently transfected the α(1a)-adrenergic receptor into COS-1 cells and determined its pharmacological characteristics by [(3)H]prazosin binding. Unlabeled prazosin had a K(i) of 0.89±0.1nM. The α(1A)-adrenergic receptor-selective antagonists, 5-methylurapidil and WB-4101, bound with high affinity and had K(i) values of 4.9±1 and 1.0±0.1nM, respectively. BMY-7378, an α(1D)-adrenergic receptor-selective antagonist, bound with low affinity (260±60nM). The 91.6% amino acid sequence identity and K(i)s of the cloned gerbil α(1a)-adrenergic receptor are similar to those of the human α(1a)-adrenergic receptor clone. These results show that the gerbil α(1a)-adrenergic receptor is representative of the human α(1a)-adrenergic receptor, lending validity to the use of the gerbil spiral modiolar artery as a model in studies of vascular disorders of the cochlea.
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Affiliation(s)
- Kelly M Witt
- Department of Pharmacology, Creighton University, 2500 California Plaza, Omaha, NE 68178, USA.
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Lendvai B, Halmos GB, Polony G, Kapocsi J, Horváth T, Aller M, Sylvester Vizi E, Zelles T. Chemical neuroprotection in the cochlea: The modulation of dopamine release from lateral olivocochlear efferents. Neurochem Int 2011; 59:150-8. [DOI: 10.1016/j.neuint.2011.05.015] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2010] [Revised: 05/12/2011] [Accepted: 05/17/2011] [Indexed: 01/16/2023]
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Abstract
OBJECTIVE Administration of steroids systematically is considered to be the most commonly accepted treatment for idiopathic sudden sensorineural hearing loss (ISSNHL). In recent years there has been increasing scientific interest in treating ISSNHL by means of local steroid delivery. Usually, intratympanic steroids are used in three main protocols, as initial treatment, as adjunctive treatment given concomitantly with systemic steroids and as salvage treatment after failure of standard therapy. The purpose of this review is to examine the published literature regarding the therapeutic value of each method of treatment and to seek answers about the best delivery technique and the optimal administration schedule. DATA SOURCES Literature review from 1996 to 2009, PubMed and Medline. STUDY SELECTION We searched for trials concerning clinical evaluation of intratympanic steroids in ISSNHL patients, as a salvage treatment, as a first line therapy and in combination with the conventional therapy. Randomized and non-randomized case control studies and case series studies were the types of trials available for review. DATA EXTRACTION All the articles described in the study selection were used for this review. DATA SYNTHESIS Statistical techniques were not used. CONCLUSION On the basis of the available literature, it seems that topical steroids can be a valuable solution for ISSNHL patients who either cannot tolerate systemic steroid therapy or are refractory to it. Concerning the combined therapy, due to the controversial results of the existing studies, it cannot be determined yet whether this treatment protocol could yield superior results as a first line therapy. The need for establishment of standard criteria of hearing recovery should be underlined.
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Papadopoulos TA, Naxakis SS, Charalabopoulou M, Vathylakis I, Goumas PD, Gartaganis SP. Exfoliation syndrome related to sensorineural hearing loss. Clin Exp Ophthalmol 2010; 38:456-61. [DOI: 10.1111/j.1442-9071.2010.02289.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Preventing hearing damage using topical dexamethasone during reversible cochlear ischemia: an animal model. Otol Neurotol 2009; 30:851-7. [PMID: 19638939 DOI: 10.1097/mao.0b013e3181b12296] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
HYPOTHESIS Local application of dexamethasone to the round window (RW) niche prevents cochlear damage caused by local reversible ischemia. BACKGROUND Cochlear ischemia induced by internal auditory artery (IAA) compression/stretching is thought to cause postoperative sensory hearing loss after attempted hearing preservation removal of acoustic neuroma tumors. Dexamethasone administered to the RW niche traveling through the membrane to the cochlear fluids may prevent ischemic damage. MATERIALS AND METHODS Ten young albino rabbits were used for this study. Ischemic episodes were induced by compressing the IAA. Laser Doppler cochlear blood flow was measured using a probe positioned at the RW niche. Transtympanic electrocochleography was measured at 4, 8, and 12 kHz. In 5 test ears, dexamethasone was administered topically at the RW for approximately 50 minutes before the IAA compressions, whereas in 5 control ears, saline was applied in the same way. Each ear underwent one 10-minute IAA compression with a 60-minute postischemic period of transtympanic electrocochleography monitoring. RESULTS In both control- and dexamethasone-treated ears, ischemic episodes measured by Laser Doppler cochlear blood flow were comparable. Fifty minutes after IAA decompression, in dexamethasone-pretreated ears, cochlear microphonic and compound action potential amplitudes at all test frequencies were 10 to 15% less reduced than those in control ears. Compound action potential latencies in dexamethasone-pretreated ears resulted in shorter latency delay than in control ears. CONCLUSION The RW seems to be an efficacious route for the administration of dexamethasone into the inner ear. Dexamethasone showed a protective effect on cochlear function after local ischemia. Transtympanic electrocochleography was found to be a sufficient and effective tool in monitoring hearing.
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Newman-Toker DE, Dy FJ, Stanton VA, Zee DS, Calkins H, Robinson KA. How often is dizziness from primary cardiovascular disease true vertigo? A systematic review. J Gen Intern Med 2008; 23:2087-94. [PMID: 18843523 PMCID: PMC2596492 DOI: 10.1007/s11606-008-0801-z] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2008] [Revised: 08/18/2008] [Accepted: 09/02/2008] [Indexed: 11/27/2022]
Abstract
OBJECTIVES To assess how frequently cardiovascular dizziness is vertigo. Recent studies suggest providers do not consider cardiovascular causes when a patient reports true vertigo (spinning/motion) as opposed to presyncope (impending faint). It is known that cardiovascular disease causes dizziness, but unknown how often such dizziness is vertiginous, as opposed to presyncopal. DATA SOURCES Systematic review of observational studies was made: Search--electronic (MEDLINE, EMBASE) and manual (references of eligible articles) search for English-language studies (1972-2007). REVIEW METHODS Inclusions Studies of >or=5 patients with confirmed cardiovascular causes for dizziness and reporting a proportion with vertigo were included. Two independent reviewers selected studies for inclusion, with differences adjudicated by a third. Study characteristics and dizziness-type proportions were abstracted. Studies were rated on methodology and quality of dizziness definitions. Differences were resolved by consensus. RESULTS We identified 1,506 citations, examined 125 full manuscripts, and included 5 studies. Principal reasons for exclusion were: abstracts--lack of original data, no cardiovascular diagnosis, or confounding exposure/disease (74%); manuscripts--failure to distinguish vertigo from other dizziness types (78%). In the three studies not using vertigo as an entry criterion (representing 1,659 patients with myocardial infarction, orthostatic hypotension, or syncope), vertigo was present in 63% (95% CI 57-69%) of cardiovascular patients with dizziness and the only dizziness type in 37% (95% CI 31-43%). Limitations include modest study quality and non-uniform definitions for vertigo. CONCLUSIONS Published data suggest that dizziness from primary cardiovascular disease may often be vertigo. Future research should assess prospectively whether dizziness type is a meaningful predictor for or against a cardiovascular diagnosis.
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Affiliation(s)
- David E Newman-Toker
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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Bektas D, Martin GK, Stagner BB, Lonsbury-Martin BL. Noise-induced hearing loss in mice treated with antiretroviral drugs. Hear Res 2008; 239:69-78. [PMID: 18384985 DOI: 10.1016/j.heares.2008.01.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2007] [Revised: 01/23/2008] [Accepted: 01/29/2008] [Indexed: 11/17/2022]
Abstract
The results reported here for CBA/CaJ mice describe the effects of regular dosing with a common antiretroviral drug combination on outer hair cell (OHC) function using measures of 2f1-f2 distortion product otoacoustic emissions (DPOAEs) and auditory brainstem responses (ABRs). Specifically, experimental mice were treated daily over a 3-mo period with the nucleoside reverse transcriptase inhibitors (NRTIs), zidovudine (ZDV) and lamivudine (3TC), dissolved in their drinking water, while their control counterparts received untreated water. DPOAE levels and ABR detection thresholds prior to and after 12 wk of NRTI treatment did not differ between experimental and control groups. To assess whether NRTI treatment potentiates the adverse effects of noise over-exposure on OHC function, both experimental and control mice were exposed 1 wk later, while still on the drug regimen, to a 10-kHz octave-band noise (OBN) at 105-dB SPL for 1h. A major outcome of the sound over-exposure episode was that the NRTI-pretreated mice showed significantly greater permanent OBN-induced reductions in DPOAE levels at 2 wk postexposure than were observed for the untreated control animals. These findings support the notion that a synergistic relationship exists between certain NRTIs and intense sounds in that such preexposure drug treatments produced greater noise-induced decreases in DPOAE activity than did noise exposure alone. This drug/noise interaction is consistent with the known harmful effects of NRTIs on cellular mitochondrial activity.
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Affiliation(s)
- Devrim Bektas
- Department of Otorhinolaryngology, Head and Neck Surgery, Karadeniz Technical University Medical School, Trabzon, Turkey
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Ruel J, Wang J, Rebillard G, Eybalin M, Lloyd R, Pujol R, Puel JL. Physiology, pharmacology and plasticity at the inner hair cell synaptic complex. Hear Res 2006; 227:19-27. [PMID: 17079104 DOI: 10.1016/j.heares.2006.08.017] [Citation(s) in RCA: 138] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2006] [Revised: 04/14/2006] [Accepted: 08/30/2006] [Indexed: 02/07/2023]
Abstract
This report summarizes recent neuropharmacological data at the IHC afferent/efferent synaptic complex: the type of Glu receptors and transporter involved and the modulation of this fast synaptic transmission by the lateral efferents. Neuropharmacological data were obtained by coupling the recording of cochlear potentials and single unit of the auditory nerve with intra-cochlear applications of drugs (multi-barrel pipette). We also describe the IHC afferent/efferent functioning in pathological conditions. After acoustic trauma or ischemia, acute disruption of IHC-auditory dendrite synapses are seen. However, a re-growth of the nerve fibres and a re-afferentation of the IHC were completely done 5 days after injury. During this synaptic repair, multiple presynaptic bodies were commonly found, either linked to the membrane or "floating" in ectopic positions. In the meantime, the lateral efferents directly contact the IHCs. The demonstration that NMDA receptors blockade delayed the re-growth of neurites suggests a neurotrophic role of NMDA receptors in pathological conditions.
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Affiliation(s)
- Jérôme Ruel
- INSERM U583-INM, Hôpital Saint Eloi, 80 Avenue Augustin Fliche, BP 74103, 34091 Montpellier cedex 5, France
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Morawski K, Telischi FF, Niemczyk K. A model of real time monitoring of the cochlear function during an induced local ischemia. Hear Res 2006; 212:117-27. [PMID: 16403609 DOI: 10.1016/j.heares.2005.05.019] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2005] [Accepted: 05/02/2005] [Indexed: 10/25/2022]
Abstract
The aim of this study was to investigate the utility of distortion product otoacoustic emissions (DPOAEs) in intraoperative monitoring (IM) of cochlear ischemic episodes in animals during internal auditory artery (IAA) compression. The IAA was exposed using the posterior fossa approach and then compressed for 3 and 5 min intervals to effect ischemia. DPOAE amplitudes and phases were measured at 4, 8, and 12 kHz geometric mean frequency (GMF). In each monitored ear, laser-Doppler cochlear blood flow (CBF) was measured. All IAA compressions resulted in rapid decrease of DPOAE amplitude and CBF, with simultaneous DPOAE phase increase. DPOAE phase changes were found to increase consistently within several seconds of IAA compression, while corresponding DPOAE amplitudes changed more slowly, with up to 30-40 s delays. Following IAA release, DPOAEs at 12 kHz GMF were characterized by longer delays in returning to baseline than those measured at lower frequencies. In some cases, CBF did not return to baseline. In this animal model, DPOAEs were found to be sensitive measures of cochlear function during transient cochlear ischemic episodes, suggesting the utility of DPOAE monitoring of auditory function during surgery of cerebello-pontine angle tumors.
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Affiliation(s)
- Krzysztof Morawski
- Department of Otolaryngology, Medical University of Warsaw, Banacha 1a Street, 02-097 Warsaw, Poland
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25
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Halmos G, Doleviczényi Z, Répássy G, Kittel A, Vizi ES, Lendvai B, Zelles T. D2 autoreceptor inhibition reveals oxygen-glucose deprivation-induced release of dopamine in guinea-pig cochlea. Neuroscience 2005; 132:801-9. [PMID: 15837140 DOI: 10.1016/j.neuroscience.2005.01.023] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/13/2005] [Indexed: 11/29/2022]
Abstract
Dopamine (DA), released from the lateral olivocochlear (LOC) efferent terminals, the efferent arm of the short-loop feedback in the cochlea, is considered as a protective factor in the inner ear since it inhibits auditory nerve dendrite firing in ischemia- or noise-induced excitotoxicity leading to sensorineural hearing loss (SNHL). In the present study we investigated the effect of oxygen-glucose deprivation (OGD), an in vitro ischemia model, on guinea-pig cochlear [(3)H]DA release in a microvolume superfusion system. We found that OGD alone failed to induce a detectable elevation of [(3)H]DA level, but in the presence of specific D(2) receptor antagonists, sulpiride and L-741,626, it evoked a significant increase in the extracellular concentration of [(3)H]DA. D(2) negative feedback receptors are involved not exclusively in the regulation of synthesis and vesicular release of DA, but also in the activation of its reuptake. Thus, D(2) receptor antagonism interferes with the powerful reuptake of DA from the extracellular space. To explore the underlying mechanism of this DA-releasing effect we applied nomifensine and found that the effect of OGD on cochlear DA release in the presence of D(2) antagonists could be inhibited by this selective DA uptake inhibitor. This finding indicates that the OGD-evoked DA release was mainly mediated through the reverse operation of the DA transporter. The two structurally different D(2) antagonists also augmented the electrical field stimulation-evoked release of DA proving the presence of D(2) autoreceptors on dopaminergic LOC terminals. Our results confirm the presence and role of D(2) DA autoreceptors in the regulation of DA release from LOC efferents, and suggest a protective local mechanism during ischemia which involves the direct transporter-mediated release of DA. Increasing the release of the protective transmitter DA locally in the inner ear may form the basis of future new therapeutic strategies in patients suffering from SNHL.
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Affiliation(s)
- G Halmos
- Institute of Experimental Medicine, Hungarian Academy of Sciences, Szigony u. 43, H-1083 Budapest, Hungary
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Okamoto Y, Hoya N, Kamiya K, Fujii M, Ogawa K, Matsunaga T. Permanent threshold shift caused by acute cochlear mitochondrial dysfunction is primarily mediated by degeneration of the lateral wall of the cochlea. Audiol Neurootol 2005; 10:220-33. [PMID: 15809501 DOI: 10.1159/000084843] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2004] [Accepted: 12/03/2004] [Indexed: 01/23/2023] Open
Abstract
Mitochondrial dysfunction in the cochlea is thought to be an important cause of sensorineural hearing loss. Recently, we have established a novel rat model with acute hearing impairment caused by exposure to the mitochondrial toxin 3-nitropropionic acid (3-NP) to analyze the mechanism of cochlear mitochondrial dysfunction. Both permanent and temporary threshold shifts were observed in this model depending on the amount of 3-NP used to induce hearing impairment. In this study, we demonstrate cochlear morphological changes in the permanent threshold shift model. Marked degeneration was detected in type 2 fibrocytes in the spiral prominence, type 4 fibrocytes in the spiral ligament, marginal cells and intermediate cells in the stria vascularis 3 h after 3-NP administration; these changes were progressive for at least 14 days. Less prominent degeneration was detected in type 1 and type 3 fibrocytes in the spiral ligament. These results indicate that permanent threshold shift caused by acute cochlear mitochondrial dysfunction is primarily mediated by cellular degeneration in the lateral wall of the cochlea, and suggest that therapy of cochlear hearing loss due to acute energy failure may be achieved through protection and regeneration of the cochlear lateral wall.
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Affiliation(s)
- Yasuhide Okamoto
- Laboratory of Auditory Disorders, National Institute of Sensory Organs, National Tokyo Medical Center, Tokyo 152-8902, Japan
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Abstract
Auditory neuropathy/dys-synchrony is a form of hearing impairment in which cochlear outer hair cell function is spared but neural transmission in the auditory pathway is disordered. This condition, or group of conditions with a common physiologic profile, accounts for approximately 7% of permanent childhood hearing loss and a significant (but as yet undetermined) proportion of adult impairment. This paper presents an overview of the mechanisms underlying auditory neuropathy/dys-synchrony-type hearing loss and the clinical profile for affected patients. In particular it examines the perceptual consequences of auditory neuropathy/dys-synchrony, which are quite different from those associated with sensorineural hearing loss, and considers currently available, and future management options.
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Affiliation(s)
- Gary Rance
- Department of Otolaryngology, The University of Melbourne, East Melbourne, Australia.
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Carvalho S, Mom T, Gilain L, Avan P. Frequency specificity of distortion-product otoacoustic emissions produced by high-level tones despite inefficient cochlear electromechanical feedback. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2004; 116:1639-1648. [PMID: 15478430 DOI: 10.1121/1.1777873] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Distortion product otoacoustic emissions (DPOAEs) are thought to stem from the outer hair cells (OHCs) around the normally narrow place tuned to the primary tone stimuli. They are thus said to be frequency-specific: their local absence should accurately pinpoint local OHC damage. Yet the influence of impaired tuning on DPOAE frequency specificity is poorly documented. Mice with local damage to OHCs were examined. Their DPOAEs were frequency-specific in that audiometric notches were accurately tracked. The same cochleae were further impaired by ischemia or furosemide injection inducing strial dysfunction with flat loss of sensitivity and tuning, while the preexisting pattern of damaged OHCs remained unaltered. Despite the loss of cochlear activity, DPOAEs produced by high-level (> or =70 dB SPL) primaries remained large in about the same interval where they had been initially normal, i.e., that with nondamaged OHCs, albeit with a slight frequency shift, of -1.1 kHz on average. Thus, the ability of DPOAEs to map structurally intact OHCs cannot be a mere consequence of cochlear tuning as it largely persists in its absence. The key element for this correct mapping is likely part of intact OHC structures (e.g., stereocilia bundles) and must have some tuning of its own.
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Affiliation(s)
- Sirley Carvalho
- Laboratory of Sensory Biophysics, School of Medicine, Clermont-Ferrand, France
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Le Prell CG, Yagi M, Kawamoto K, Beyer LA, Atkin G, Raphael Y, Dolan DF, Bledsoe SC, Moody DB. Chronic excitotoxicity in the guinea pig cochlea induces temporary functional deficits without disrupting otoacoustic emissions. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2004; 116:1044-56. [PMID: 15376671 DOI: 10.1121/1.1772395] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Brief cochlear excitotoxicity produces temporary neural swelling and transient deficits in auditory sensitivity; however, the consequences of long-lasting excitotoxic insult have not been tested. Chronic intra-cochlear infusion of the glutamate agonist AMPA (a-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) resulted in functional deficits in the sound-evoked auditory brainstem response, as well as in behavioral measures of hearing. The electrophysiological deficits were similar to those observed following acute infusion of AMPA into the cochlea; however, the concentration-response curve was significantly shifted as a consequence of the slower infusion rate used with chronic cochlear administration. As observed following acute excitotoxic insult, complete functional recovery was evident within 7 days of discontinuing the AMPA infusion. Distortion product otoacoustic emissions were not affected by chronic AMPA infusion, suggesting that trauma to outer hair cells did not contribute to AMPA-induced deficits in acoustic sensitivity. Results from the current experiment address the permanence of deficits induced by chronic (14 day) excitotoxic insult as well as deficits in psychophysical detection of longer duration acoustic signals.
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Affiliation(s)
- Colleen G Le Prell
- Kresge Hearing Research Institute, Department of Otolaryngology, University of Michigan Medical School, Ann Arbor, Michigan 48109-0506, USA.
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Gouveris H, Selivanova O, Mann W. Intratympanic dexamethasone with hyaluronic acid in the treatment of idiopathic sudden sensorineural hearing loss after failure of intravenous steroid and vasoactive therapy. Eur Arch Otorhinolaryngol 2004; 262:131-4. [PMID: 15747106 DOI: 10.1007/s00405-004-0772-6] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2003] [Accepted: 01/30/2004] [Indexed: 12/01/2022]
Abstract
The purpose of this prospective study was to test whether intratympanic application of dexamethasone/hyaluronic acid improves hearing outcome in patients with pantonal idiopathic sudden sensorineural hearing loss (ISSHL), in patients with sudden deafness or sudden profound SHL and in patients with predominant high-frequency ISSHL who are refractory to intravenous steroid and vasoactive therapy. The study took place in an academic tertiary referral hospital involving 21 patients with pantonal ISSHL, 10 patients with sudden deafness or sudden profound SHL and 9 patients with a high-frequency ISSHL. Intratympanic dexamethasone/hyaluronic acid was administered in the affected ear. Hearing was evaluated by means of standard pure-tone audiometry. The differences between pure-tone hearing thresholds by air conduction before intravenous therapy and before the beginning of the intratympanic therapy, as well as before and after intratympanic therapy, were calculated. Statistical analysis was performed by means of the Wilcoxon's test for paired samples. Intratympanic injection of dexamethasone/hyaluronic acid results in a significant global (pantonal) improvement in hearing in patients with pantonal ISSHL. It also effects improvement in hearing at selected frequencies (namely at 1.5 and 3 kHz) in patients with a predominant high-frequency ISSHL and at selected frequencies (namely at 0.5, 0.75 and 1 kHz) in patients with sudden deafness or sudden profound SHL. Neither systemic nor local side effects were observed. Intratympanic administration of dexamethasone/hyaluronic acid provides a safe and efficacious therapeutic option for the treatment of patients with pantonal and high-frequency ISSHL who don't respond to intravenous steroid and vasoactive therapy.
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Affiliation(s)
- Haralampos Gouveris
- Department of Otorhinolaryngology and Head and Neck Surgery, University of Mainz, Langenbeckstrasse 1, 55131, Mainz, Germany.
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Morawski K, Telischi FF, Merchant F, Namyslowski G, Lisowska G, Lonsbury-Martin BL. Preventing internal auditory artery vasospasm using topical papaverine: an animal study. Otol Neurotol 2003; 24:918-26. [PMID: 14600475 PMCID: PMC1769327 DOI: 10.1097/00129492-200311000-00017] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Internal auditory artery (IAA) spasm is thought to be one of the causes of postoperative sensory hearing loss after attempted hearing preservation removal of an acoustic neuroma. The use of topical papaverine, a nonspecific vasodilator, to prevent vascular insufficiency to the inner ear and to improve hearing outcomes has been suggested but not proven. MATERIALS AND METHODS Vasospasm was mechanically induced by compressing the IAA in the control ears of six rabbits after application of topical saline. The subsequent reduction of cochlear blood flow (CBF) was measured using a laser-Doppler (LD) flow-monitoring technique. Functional loss of cochlear activity was verified with distortion product otoacoustic emissions (DPOAE). The contralateral experimental ears were treated with the topical application of papaverine directly to the IAA and cochleovestibular nerve complex. CBF and DPOAE were compared between the control and papaverine treated ears for 3-minute and 5-minute IAA compressions. RESULTS Every control ear demonstrated some degree of postcompression IAA vasospasm (i.e., reduced CBF) and reduction of DPOAE. Nearly complete recovery of CBF and DPOAE to baseline was observed in all of the papaverine treated ears. CONCLUSIONS An animal model of IAA vasospasm was described. Mechanically induced vasospasm of the IAA was prevented by the topical application of papaverine. These findings have clinical implications for surgical procedures involving the internal auditory canal/cerebellopontine angle such as acoustic neuroma removal.
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Affiliation(s)
| | - Fred F. Telischi
- University of Miami Ear Institute, Department of Otolaryngology, Miami, Florida; and
| | - Faisal Merchant
- University of Miami Ear Institute, Department of Otolaryngology, Miami, Florida; and
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Morawski K, Telischi FF, Merchant F, Abiy LW, Lisowska G, Namyslowski G. Role of mannitol in reducing postischemic changes in distortion-product otoacoustic emissions (DPOAEs): a rabbit model. Laryngoscope 2003; 113:1615-22. [PMID: 12972944 PMCID: PMC1769330 DOI: 10.1097/00005537-200309000-00039] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
OBJECTIVES The aim of this study was to observe the effects of mannitol, administered topically at the round window (RW), on cochlear blood flow (CBF) and distortion-product otoacoustic emission (DPOAE) after repeated episodes of cochlear ischemia. METHODS Ten young rabbits were used for this study. Reversible ischemic episodes within the cochlea were induced by directly compressing the internal auditory artery (IAA). CBF was measured using a laser-Doppler (LD) probe positioned at the RW niche. DPOAEs were measured at 4, 8, and 12 kHz geometric mean frequency (GMF) using 60 dB sound pressure level (SPL) primary tone stimuli. In five test ears, mannitol was administered topically at the RW for 30 minutes before the IAA compressions. In five control ears, the IAA compressions were undertaken without application of RW medication. Each ear underwent three 5 minute IAA compressions with a 60 minute rest period between compressions. RESULTS In the control animals, it was observed that a progressive reduction in DPOAE level followed each successive IAA compression at all three test frequencies. The reduction in DPOAE amplitudes was consistently greater at the higher test frequencies. In the test rabbits, the RW administration of mannitol resulted in significantly less reduction in DPOAE level measures after repeated IAA compressions. For example, 30 minutes after reperfusion at 12 kHz GMF, DPOAE levels in the control ears were reduced by 1.5, 6.0, and 16 dB, compared with 1.5, 4.0, and 6.0 dB in the mannitol test ears. CONCLUSIONS Mannitol appears to exert a protective effect on cochlear function after periods of ischemia. The RW appears to be an efficacious route for topical administration of mannitol into the inner ear.
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Affiliation(s)
- Krzysztof Morawski
- From the Ear, Nose and Throat Department, Silesian Medical Academy, Zabrze, Poland
| | - Fred F. Telischi
- Department of Otolaryngology, University of Miami Ear Institute, Miami, FL; and
- Department of Biomedical Engineering, University of Miami, Miami, FL, U.S.A
| | - Faisal Merchant
- Department of Otolaryngology, University of Miami Ear Institute, Miami, FL; and
| | - Lidet W. Abiy
- Department of Biomedical Engineering, University of Miami, Miami, FL, U.S.A
| | - Grazyna Lisowska
- From the Ear, Nose and Throat Department, Silesian Medical Academy, Zabrze, Poland
| | - Grzegorz Namyslowski
- From the Ear, Nose and Throat Department, Silesian Medical Academy, Zabrze, Poland
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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: 35] [Impact Index Per Article: 1.7] [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.
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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
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Affiliation(s)
- Kenichiro Koga
- Department of Otolaryngology, Ehime University School of Medicine, Ehime, 791-0295 Japan.
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Tabuchi K, Tsuji S, Fujihira K, Oikawa K, Hara A, Kusakari J. Outer hair cells functionally and structurally deteriorate during reperfusion. Hear Res 2002; 173:153-63. [PMID: 12372643 DOI: 10.1016/s0378-5955(02)00349-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Transient ischemia of the cochlea was induced in 65 albino guinea pigs by pressing the labyrinthine artery, and the effects of cochlear reperfusion on cochlear potentials (endocochlear potential, compound action potential and cochlear microphonics (CM)) and structural changes in hair cells were examined. Although 15 min ischemia did not elevate the post-ischemic CM pseudo-threshold as compared with the pre-ischemic value, ischemia of 30 min or longer significantly elevated the CM pseudo-threshold. CM amplitude tended to progressively decrease during the reperfusion period in the animals subjected to 45 or 60 min ischemia. After transient ischemia, outer hair cells (OHCs) were swollen and exhibited alterations of the nucleus. Severer structural deterioration of OHCs was induced by 4 h reperfusion than ischemia itself when the ischemic period was 45 or 60 min. Perilymphatic perfusion of dimethylthiourea, a hydroxyl radical scavenger, partially ameliorated the elevation of the CM pseudo-thresholds and the structural changes of OHCs. These results indicate that cochlear reperfusion induces functional and structural deterioration of OHC probably by hydroxyl radical generation.
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Affiliation(s)
- Keiji Tabuchi
- Department of Otolaryngology, Institute of Clinical Medicine, University of Tsukuba, 1-1-1 Tennodai, Japan
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35
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Mom T, Bonfils P, Gilain L, Avan P. Origin of cubic difference tones generated by high-intensity stimuli: effect of ischemia and auditory fatigue on the gerbil cochlea. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2001; 110:1477-1488. [PMID: 11572358 DOI: 10.1121/1.1390337] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Cubic difference tone (CDT) otoacoustic emissions are thought to arise from the feedback loop allowing outer hair cells to enhance the sensitivity and tuning of the organ of Corti. The existence of residual CDTs during complete cochlear ischemia is therefore disturbing. That stimulus intensities must exceed 50-60 dB SPL for residual CDTs to be recorded and for level notches to be present in CDT growth functions is often cited as evidence for a two-component, "active/passive" model: one component, the residual one, would originate from a passive, hardly vulnerable mechanism and thus be unsuitable for hearing screening purposes. This model was probed in gerbil ears after complete interruption of the cochlear blood flow. Cochlear potentials and CDTs were controlled simultaneously through continuous monitoring of CDT level and phase for 50 and 60 dB SPL stimuli and group-delay measurements. After a clear initial decay, CDT levels elicited at 60 dB SPL plateaued for several minutes at about 20 dB below initial level, and when early level notches were observed, CDT phase changes remained minor. The CDT group delays decreased by less than 30%. Later CDT level notches were associated with sharp phase reversals but the similarity between CDT characteristics before and after a notch was hardly consistent with a two-component interpretation. When mild sound overexposure (pure tone, 90-95 dB SPL, 15-30 min) had been performed prior to ischemia, little or no ischemic CDT came from the frequency bands where auditory fatigue had been detected (within 1 kHz), irrespective of the stimulus intensity. It suggests that instead of being passive, residual ischemic CDTs were vulnerable and produced according to a near-normal tonotopy by the same mechanisms that were sensitive to auditory fatigue. All the results lined up with a simple feedback model of cochlear function assuming a single CDT source related to mechano-electrical transduction in outer hair cells. More parsimonious than a two-component model, it posits that although early stages of ischemia dramatically impair the overall performance of the cochlea, the nonlinear mechanical stages responsible for the existence of CDTs keep working albeit at higher intensities.
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Affiliation(s)
- T Mom
- Laboratory of Sensory Biophysics, School of Medicine, Clermont-Ferrand, France
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36
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Tabuchi K, Okubo H, Fujihira K, Tsuji S, Hara A, Kusakari J. Protection of outer hair cells from reperfusion injury by an iron chelator and a nitric oxide synthase inhibitor in the guinea pig cochlea. Neurosci Lett 2001; 307:29-32. [PMID: 11516567 DOI: 10.1016/s0304-3940(01)01919-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
To examine whether an active process of the cochlea was injured by ischemia-reperfusion, time courses of distortion-product otoacoustic emissions (DPOAEs) were examined before, during and after 30 min cochlear ischemia using albino guinea pigs. DPOAEs decreased to the minimum level when the animals were subjected to ischemia. When the cochlea was recirculated, DPOAEs initially recovered with time until 20 min after the onset of reperfusion. However, thereafter the amplitude of DPOAEs gradually decreased toward the noise level. Administration of deferoxamine (an iron chelator) or N-nitro-L-arginine (a nitric oxide synthase inhibitor) ameliorated this decrease of DPOAEs during reperfusion and significantly increased the DPOAE amplitudes 60 min after the onset of reperfusion as compared with those in non-treated animals. These results suggest that cochlear reperfusion as well as ischemia injured the active process of the cochlea and that free radicals and nitric oxide play important roles in this injury.
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Affiliation(s)
- K Tabuchi
- Department of Otolaryngology, Institute of Clinical Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8575, Japan
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37
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Ruan RS, Leong SK, Yeoh KH. Effects of nitric oxide on normal and ischemic cochlea of the guinea pig. Exp Neurol 2001; 169:200-7. [PMID: 11312572 DOI: 10.1006/exnr.2001.7632] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
To determine whether nitric oxide (NO)/peroxynitrite plays any role in neurodestruction observed in ischemic cochlea of the guinea pig, the effects of NO donors like S-nitrosocysteine (S-NC) and nitroglycerin (NTG), peroxynitrite generators like 3-morpholinosydnonimine (SIN-1), peroxynitrite inhibitors like superoxide dismutase plus catalase (SOD/Cat), as well as NOS inhibitors like N(G)-nitro-l-arginine methyl ether (L-NAME), were tested on normal and ischemic cochleae. Various concentrations of S-NC and SIN-1 were introduced into the perilymphatic space of normal guinea pig cochlea. Quantitative scanning electron microscopy of inner and outer hair cells was carried out 2 days later. To determine the level of NO in the cochlea after 20 to 120 min of ischemia, nitrites/nitrates in the perilymph were measured. The effects of NO on the ischemic cochlea were tested by infusion of SOD/Cat, L-NAME, S-NC, and NTG into the perilymphatic space just before decapitation. Introduction of fixative into the cochlea was delayed for 15 min to investigate the effects of the chemicals on nerve endings at the base of inner hair cells. The results showed that the level of nitrites/nitrates tended to decline with increasing time of ischemia. There was no significant hair cell loss in the cochleae treated with SIN-1 or S-NC. At 15 min after ischemia, most of the nerve endings at the base of the inner hair cells were protected from damage when 1 mM S-NC or NTG was infused into the perilymph. Taken together, the results indicate that NO/peroxynitrite is unlikely to be involved in the neurodestruction in the ischemic cochlea. In fact, exogenous NO may have a neural protective effect.
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Affiliation(s)
- R S Ruan
- Department of Otolaryngology, National University Hospital, Lower Kent Ridge Road, 119074, Singapore
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Halmos G, Gáborján A, Lendvai B, Répássy G, Szabó LZ, Vizi ES. Veratridine-evoked release of dopamine from guinea pig isolated cochlea. Hear Res 2000; 144:89-96. [PMID: 10831868 DOI: 10.1016/s0378-5955(00)00053-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Dopamine released from the lateral olivocochlear efferent system is thought to inhibit the toxic effect of the extreme glutamate outflow from the inner hair cells during ischemia or acoustic trauma. Using in vitro microvolume superfusion, we have studied the release of [(3)H]dopamine from the lateral olivocochlear efferent bundle of guinea pig in response to accumulation of [Na(+)](i), under condition characteristics of ischemia. Veratridine, that acts only on excitable membranes as a specific activator of voltage-sensitive sodium channels, significantly increased the electrically evoked release of [(3)H]dopamine, which was completely inhibited by tetrodotoxin. Dizocilpine (MK-801), a non-competitive NMDA-receptor antagonist, and GYKI-52466, a selective non-NMDA-receptor antagonist, had no effect on veratridine-induced [(3)H]dopamine release. Our data provide further evidence that the cochlear release of dopamine is of neural origin and possibly independent on a local effect of glutamate. The veratridine-induced transmitter release in the cochlea will be a very useful method in studying the effect of drugs on ischemic injury.
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Affiliation(s)
- G Halmos
- Department of Pharmacology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest
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39
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Piltcher O, Cigana L, Friedriech J, Ribeiro FA, da Costa SS. Sensorineural hearing loss among sickle cell disease patients from southern Brazil. Am J Otolaryngol 2000; 21:75-9. [PMID: 10758990 DOI: 10.1016/s0196-0709(00)85001-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
PURPOSE A case-control study was done to confirm the higher prevalence of sensorineural hearing loss (SNHL) among sickle cell patients (HbSS) from southern Brazil. PATIENTS AND METHODS Twenty-eight patients and 28 matched normal controls were studied. Besides complete anamneses and physical otolaryngological examination, all individuals had audiometric and tympanometric testings to determine the presence of SNHL or middle ear problems. The only significant difference between groups was the presence of a positive history of otologic symptoms (hearing loss, dizziness or tinnitus) and neurological sequelae in the HbSS patients. RESULTS Six patients (21.4%) presented with SNHL compared with one control (3.6%) (Fisher's one-tailed P = .05; OR, 7.36 (95% CI, 0.82, 65.83). The average age of HbSS diagnosis was higher among the patients with SNHL (10 years +/- 8.3) than those without SNHL (5.43 years +/- 5.65), but this was not significant (analysis of variance P > .05). More patients 25 years and older on the examination date had SNHL than younger patients (Fisher's 2-tailed P < .05). Sixty-seven percent of the patients with SNHL had alterations in the acoustic reflex, and a surprising 27% of the patients without NSHL also presented with some elevation or an absence of acoustic reflex. CONCLUSIONS These data indicate that patients with HbSS from southern Brazil are more predisposed to the development of sensorineural hearing problems than the general population.
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Affiliation(s)
- O Piltcher
- Hospital de Clinicas de Porto Alegre and the Faculdade de Ciências Médicas da Santa Casa de Sao Paulo, Brazil
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40
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Pujol R, Puel JL. Excitotoxicity, synaptic repair, and functional recovery in the mammalian cochlea: a review of recent findings. Ann N Y Acad Sci 1999; 884:249-54. [PMID: 10842598 DOI: 10.1111/j.1749-6632.1999.tb08646.x] [Citation(s) in RCA: 202] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Besides its fast excitatory properties, glutamate is known to have neurotoxic properties when released in large amounts or when incompletely recycled. This so-called excitotoxicity is involved in a number of acute and/or degenerative forms of neuropathology such as epilepsy, Alzheimer's, Parkinson's, stroke, and retinal ischemia. In the cochlea, excitotoxicity may occur in two pathological conditions: anoxia and noise trauma. It is characterized by a two-step mechanism: (1) An acute swelling, which primarily depends on the AMPA/kainate type of receptors, together with a disruption of the postsynaptic structures (type I afferent dendrites) resulting in a loss of function. Within the next 5 days, synaptic repair may be observed with a full or a partial (acoustic trauma) recovery of cochlear potentials. (2) The second phase of excitotoxicity, which may develop after strong and/or repetitive injury, consists of a cascade of metabolic events triggered by the entry of Ca2+, which leads to neuronal death in the spiral ganglion. Ongoing experiments in animals, tracking the molecular basis of both these processes, presages the development of new pharmacological strategies to help neurites to regrow and reconnect properly to the IHCs, and to prevent or delay neuronal death in the spiral ganglion. Human applications should follow, and a local (transtympanic) strategy against cochlear excitotoxicity may, in the near future, prove to be helpful in ischemic- or noise-induced sudden deafness, as well as in the related tinnitus.
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Affiliation(s)
- R Pujol
- INSERM, Montpellier, France.
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41
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Abstract
Cochlear ischemia induces a sensorineural hearing loss, in part through a fast functional impairment of outer hair cellls. Assuming that the cochlea is rendered fragile during ischemia and reperfusion and that stimulation itself can jeopardize its functional recovery, we used a model of reversible selective cochlear ischemia in Mongolian gerbils to establish what type of sound exposure can be deleterious during and immediately after reversible ischemia. Several groups of gerbils were used, with different ischemia durations and levels of sound exposure. Control groups were only exposed to tones at 80 and 90 dB SPL during 30 min, while other groups underwent complete and fully reversible blockage of the labyrinthine artery, during 5.5 or 8 min, and were exposed to 60 or 80 dB SPL tones during 30 min. The amount of ischemia and reperfusion was measured by means of laser Doppler velocimetry, whereas outer hair cells' function was continuously monitored through distortion-product otoacoustic emissions (DPOAEs). The losses of DPOAE levels after 8 min transient ischemia and 60 dB SPL exposure were as large as those induced by 80 dB SPL exposures combined with 5.5 min ischemia, or 90 dB SPL exposures without ischemia, with a maximum loss around 25-30 dB, half an octave above the stimulus frequency. These results give evidence for an extremely high cochlear vulnerability to low-level sound exposure when associated with reversible ischemia. This vulnerability may have important clinical consequences in patients with cochlear circulatory disturbances.
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Affiliation(s)
- T Mom
- Laboratoire de Biophysique Sensorielle (EA 2667), Faculté de Médecine, Université d'Auvergne, P.O. Box 38, 63001, Clermont-Ferrand, France
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Ohlemiller KK, Dugan LL. Elevation of reactive oxygen species following ischemia-reperfusion in mouse cochlea observed in vivo. Audiol Neurootol 1999; 4:219-28. [PMID: 10436314 DOI: 10.1159/000013845] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
An in vivo method for assessment of changes in hydroxyl radical levels in cochlear perilymphatic spaces is described and applied to cochlear ischemia-reperfusion in the mouse. Cochlear blood flow was reversibly reduced by compression of the anterior inferior cerebellar arterial network. Changes in the production of hydroxyl radicals, used as an index of tissue production of reactive oxygen species (ROS), were determined by measuring the conversion of salicylate to 2,3-dihydroxybenzoic acid. Low levels of salicylate (0.1 mM) in artificial perilymph were applied by perfusion of the cochlea using a round window entry and apical exit. Perfusate was collected and analyzed by high-performance liquid chromatography. Forty minutes of partial ischemia led to a > 10-fold average increase over baseline in the concentration of hydroxyl radical, which increase persisted for at least 40-80 min following reperfusion. Our observations support previous results obtained using less direct methods, indicating that cochlear ischemia-reperfusion and related damage is associated with elevated ROS levels. Development of an in vivo method for assessing changes in cochlear ROS in mice will facilitate the study of the relation between deafness genes, vulnerability to insults and dynamics of cellular processes that produce and regulate ROS.
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Affiliation(s)
- K K Ohlemiller
- Research Department, Central Institute for the Deaf, Washington University School of Medicine, St. Louis, MO 63110, USA.
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43
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Mom T, Telischi FF, Martin GK, Lonsbury-Martin BL. Measuring the cochlear blood flow and distortion-product otoacoustic emissions during reversible cochlear ischemia: a rabbit model. Hear Res 1999; 133:40-52. [PMID: 10416863 DOI: 10.1016/s0378-5955(99)00056-8] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Impairment to the cochlear blood flow likely induces many types of sensorineural hearing loss. Models using several small laboratory animals have been described in the literature that permit the simultaneous monitoring of the cochlear blood flow with laser-Doppler flowmetry and cochlear function using evoked responses. However, these models have not permitted a direct application of the resulting knowledge to the human condition, primarily due to differences in the translucence of the otic capsule between species. In the present study, to approximate conditions relevant to the human patient, the rabbit was utilized to develop a procedure in which laser-Doppler flowmetry could be used to measure the cochlear blood flow in an animal with an opaque otic capsule. At the same time, the cochlear function was monitored non-invasively using distortion-product otoacoustic emissions. In this manner, a laser-Doppler probe was positioned in the round window niche and the cochlear function measured using distortion-product otoacoustic emissions during a systematic series of ischemic episodes. Cochlear ischemia was produced by deliberately compressing the eighth nerve complex at the porus of the internal acoustic meatus, for periods lasting from 1-3 min, while cochlear blood flow and distortion-product otoacoustic emission measures were obtained simultaneously before, during and following the occlusion. Results demonstrated that the cochlear blood flow sharply decreased within 1 s after compression onset, whereas distortion-product otoacoustic emissions showed obstruction-induced changes after a delay of several seconds, provided that the blood flow decreased, at least 40%. Similarly, upon release of the compression, the cochlear blood flow began to recover within 1 s, whereas the recovery of the corresponding distortion-product otoacoustic emissions was slightly delayed. Although not apparent in the distortion-product otoacoustic emission recovery time course, the cochlear blood flow consistently overshot its initial baseline value during the recovery process. Thus, although cochlear ischemia produced changes in the distortion-product otoacoustic emission activity that generally followed the resulting alterations in the cochlear blood flow, the detailed relationship between the two measures was complex.
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Affiliation(s)
- T Mom
- Service d'Otorhinolaryngologie et Laboratoire de Biophysique Sensorielle (2R3), Faculté de Médecine, Université D'Auvergne, Clermont-Ferrand, France.
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Tabuchi K, Ito Z, Wada T, Hara A, Kusakari J. The effect of mannitol upon cochlear dysfunction induced by transient local anoxia. Hear Res 1998; 126:28-36. [PMID: 9872131 DOI: 10.1016/s0378-5955(98)00142-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Transient local anoxia of the cochlea was induced by pressing the labyrinthine artery, and compound action potential (CAP) or endocochlear potential (EP) was measured before and after transient local anoxia ranging from 5 to 60 min using 106 albino guinea pigs. The complete interruption of the cochlear blood flow by this procedure and its full restoration after releasing the pressure on the artery was confirmed by a laser-Doppler flowmeter. The anoxia of less than 10 min induced no post-anoxic cochlear dysfunction, whereas the anoxia of a longer duration induced an irreversible dysfunction of the cochlea. It was evident that the post-anoxic recovery of the CAP threshold was worse as the anoxia period was prolonged, and CAP was almost completely abolished after 60-min anoxia. In animals which were administered mannitol intravenously just after the restoration of the cochlear blood circulation, the recovery of the CAP threshold was significantly better than that in the control animals, when the animals were subjected to local anoxia of 15- to 30-min duration. No beneficial effect, however, was observed in the 60-min anoxia group. In conclusion, local anoxia of 10 min or longer caused cochlear dysfunction, which was partially but significantly alleviated by mannitol.
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Affiliation(s)
- K Tabuchi
- Department of Otolaryngology, Institute of Clinical Medicine, University of Tsukuba, Tennodai, Japan
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45
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Abstract
OBJECTIVE We describe an animal model of auditory neuropathy in which subjects have extensive, scattered inner haircell loss but with a relatively intact outer haircell population. DESIGN Such a pattern of cochlear haircell damage can be produced in the chinchilla by treatment with the anticancer agent carboplatin. RESULTS In these subjects, otoacoustic emissions (OAEs) and cochlear microphonics remain normal while auditory brain stem evoked potential (ABR) thresholds are significantly elevated. However, in the same subjects, central auditory neurons (in the inferior colliculus) have response thresholds that are considerably lower (by up to 50 dB) than ABR thresholds. These findings parallel the characteristics of auditory neuropathy in humans, in which absent or abnormal ABRs are recorded in patients with only mild to moderate audiometric thresholds and preserved OAEs. CONCLUSIONS We suggest that scattered inner haircell lesions also can result from long-term cochlear hypoxia, and we propose that this is a likely candidate for the etiology of many types of auditory neuropathy in human subjects.
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Affiliation(s)
- R V Harrison
- Department of Otolaryngology, University of Toronto and The Hospital For Sick Children, Ontario, Canada
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46
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The glutamate receptor subunit delta1 is highly expressed in hair cells of the auditory and vestibular systems. J Neurosci 1997. [PMID: 9295397 DOI: 10.1523/jneurosci.17-19-07523.1997] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
In the inner ear, fast excitatory synaptic transmission is mediated by ionotropic glutamate receptors, including AMPA, kainate, and NMDA receptors. The recently identified delta1 and delta2 glutamate receptors share low homology with the other three types, and no clear response or ligand binding has been obtained from cells transfected with delta alone or in combination with other ionotropic receptors. Studies of mice lacking expression of delta2 show that this subunit plays a crucial role in plasticity of cerebellar glutamatergic synapses. In addition, these mice show a deficit in vestibular compensation. These findings and the nature of glutamatergic synapses between vestibulocochlear hair cells and primary afferent dendrites suggest that delta receptors may be functionally important in the inner ear and prompted us to investigate the expression of delta receptors in the cochlea and peripheral vestibular system. Reverse transcription and DNA amplification by PCR combined with immunocytochemistry and in situ hybridization were used. Our results show that the expression of delta1 in the organ of Corti is intense and restricted to the inner hair cells, whereas delta1 is expressed in all spiral ganglion neurons as well as in their satellite glial cells. In the vestibular end organ, delta1 was highly expressed in both hair cell types and also was expressed in the vestibular ganglion neurons. The prominent expression of delta1 in inner hair cells and in type I and type II vestibular hair cells suggests a functional role in hair cell neurotransmission.
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47
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Furness DN, Lehre KP. Immunocytochemical localization of a high-affinity glutamate-aspartate transporter, GLAST, in the rat and guinea-pig cochlea. Eur J Neurosci 1997; 9:1961-9. [PMID: 9383219 DOI: 10.1111/j.1460-9568.1997.tb00763.x] [Citation(s) in RCA: 96] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Glutamate transporters play an important role in the reuptake of glutamate after its release from glutamatergic synapses. Four such transporters have so far been cloned from the rat brain. One, the glutamate-aspartate transporter GLAST, has been detected in the mammalian cochlea, in which the principal afferent synapse of the auditory nerve, between the inner hair cells and neurites of type I spiral ganglion neurons, has been suggested to be glutamatergic. The distribution of GLAST was therefore investigated to provide clues to the handling of glutamate in the cochlea. This was studied using light and electron microscopic immunocytochemistry in rats and guinea pigs with antibodies raised against synthetic peptides based on the sequence for GLAST. Significant immunoreactivity was found in the myelin sheath formed by satellite cells surrounding the type I spiral ganglion neurons, and along the plasma membranes of supporting cells around the inner hair cells; other cells in both locations were only weakly labelled, if at all. The absence of substantial numbers of synapses in the spiral ganglion suggests that GLAST is unlikely to be associated with the uptake of synaptic glutamate after release in this region. Immunoreactivity associated with the inner hair cells is consistent with the utilization of glutamate at the afferent synapse.
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Affiliation(s)
- D N Furness
- Department of Communication and Neuroscience, Keele University, Staffordshire, UK
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48
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Hakuba N, Gyo K, Yanagihara N, Mitani A, Kataoka K. Efflux of glutamate into the perilymph of the cochlea following transient ischemia in the gerbil. Neurosci Lett 1997; 230:69-71. [PMID: 9259466 DOI: 10.1016/s0304-3940(97)00462-x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Using a microdialysis technique followed by an enzyme cycling analysis, we measured changes in the glutamate levels in the perilymph of gerbil cochleae before, during and after transient ischemic insult. The basal glutamate level in perilymph was 0.35 +/- 0.22 pmol/microl. An almost immediate and continuous rise in the level of glutamate occurred after the ischemic insult, which advanced even further after recirculation; the average concentration was higher than 40 pmol/microl 55 min after recirculation. The compound action potentials (CAP) monitoring the auditory function totally disappeared after ischemic insult. However, CAP reappeared after recirculation; the threshold for acoustic stimulation was higher than that observed at the pre-ischemic state.
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Affiliation(s)
- N Hakuba
- Department of Otolaryngology, Ehime University School of Medicine, Japan.
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49
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Mom T, Avan P, Romand R, Gilain L. Monitoring of functional changes after transient ischemia in gerbil cochlea. Brain Res 1997; 751:20-30. [PMID: 9098564 DOI: 10.1016/s0006-8993(96)01388-1] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Ischemia and reperfusion are involved in numerous sensorineural pathologies. A model of reversible cochlear ischemia has been designed in Mongolian gerbil. Selective labyrinthine ischemia of variable duration (4-10 min) was achieved through a posterior transcranial approach. Ischemia and reperfusion were controlled with the help of laser Doppler velocimetry. Functional changes were monitored every 1-10 s throughout experiments, using cochlear potentials and otoacoustic emissions. After interruption of blood flow, all signals rapidly began to decay. In contrast to cochlear potentials, otoacoustic emissions always exhibited a plateau before reaching noise floor only after approximately 4-5 min. Upon ischemia release, cochlear blood flow recovered instantly and completely and cochlear potentials rapidly improved in most cases, in contrast to otoacoustic emissions that underwent a delayed decay after immediate partial recovery. The phase and group latency of otoacoustic emissions exhibited only small changes throughout ischemia and reperfusion, suggesting adaptive rather than damaging mechanisms. Cochlear function returned to normal after 5 min 30 s ischemia but longer complete ischemia sometimes led to irreversible damage despite the systematic presence of some recovery just after ischemia release. This behavior suggests that reperfusion in itself can be deleterious to a sensorineural organ and this model can be useful for identifying the noxious mechanisms of ischemia and reperfusion.
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Affiliation(s)
- T Mom
- Laboratory of Audition, School of Medicine, University of Auvergne, Clermont-Ferrand, France
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50
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Ford MS, Maggirwar SB, Rybak LP, Whitworth C, Ramkumar V. Expression and function of adenosine receptors in the chinchilla cochlea. Hear Res 1997; 105:130-40. [PMID: 9083810 DOI: 10.1016/s0378-5955(96)00204-3] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Previous studies indicate the presence of adenosine receptors in the cochlear tissues obtained from different animals. This study was initiated to determine the subtypes of adenosine receptor (AR) present in the chinchilla cochlea and to assess their function. Radioligand binding studies demonstrate the presence of both the A1AR and A3AR in membranes prepared from the cochlea, using the radioligands [3H]DPCPX and [125I]APNEA. Estimates of the number (Bmax) of A1AR and A1AR plus A3AR by saturation curves were 118 +/- 13 and 417 +/- 120 fmol/mg, respectively, with the respective equilibrium dissociation constants (Kd) averaging 2.7 +/- 0.2 and 26.3 +/- 13.8 nM. No significant number of A2aAR were detected using [3H]CGS21680. The nonhydrolyzable adenosine analog R-phenylisopropyladenosine (R-PIA, 1 microM) elicited a small but significant degree of inhibition of forskolin-stimulated adenylyl cyclase activity (10.4 +/- 2.5%) in cochlear membrane preparations, which was insensitive to blockade by theophylline (100 microM). Furthermore, R-PIA elicited an increase in inositol 1,4,5-trisphosphate production in dissociated cell preparations obtained from the cochlea. No significant effect of R-PIA was observed on auditory measures such as auditory brainstem evoked response, cochlear action potential and endocochlear potential following round window application. However, round window application of R-PIA elicited significant increases in the activities of antioxidant enzymes such as superoxide dismutase and glutathione peroxidase and significantly reduced the levels of malondialdehyde, a marker of lipid peroxidation. These results suggest a potential cytoprotective role of adenosine in the cochlea against oxidative damage.
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MESH Headings
- Adenosine/analogs & derivatives
- Adenosine/metabolism
- Animals
- Binding, Competitive
- Blotting, Western
- Catalase/metabolism
- Chinchilla
- Cochlea/cytology
- Cochlea/drug effects
- Cochlea/metabolism
- Cochlear Microphonic Potentials/drug effects
- Electrophoresis, Polyacrylamide Gel
- Evoked Potentials, Auditory, Brain Stem/drug effects
- Glutathione Peroxidase/metabolism
- Glutathione Reductase/metabolism
- Inositol 1,4,5-Trisphosphate/metabolism
- Lipid Peroxidation/drug effects
- Malondialdehyde/metabolism
- Oxidative Stress/drug effects
- Phenethylamines/metabolism
- Phenylisopropyladenosine/metabolism
- Phenylisopropyladenosine/pharmacology
- Purinergic P1 Receptor Agonists
- Purinergic P1 Receptor Antagonists
- Radioligand Assay
- Receptors, Purinergic P1/metabolism
- Receptors, Purinergic P1/physiology
- Round Window, Ear/drug effects
- Superoxide Dismutase/metabolism
- Xanthines/metabolism
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Affiliation(s)
- M S Ford
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield 62794, USA
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