1
|
Agrawal Y, Merfeld DM, Horak FB, Redfern MS, Manor B, Westlake KP, Holstein GR, Smith PF, Bhatt T, Bohnen NI, Lipsitz LA. Aging, Vestibular Function, and Balance: Proceedings of a National Institute on Aging/National Institute on Deafness and Other Communication Disorders Workshop. J Gerontol A Biol Sci Med Sci 2020; 75:2471-2480. [PMID: 32617555 PMCID: PMC7662183 DOI: 10.1093/gerona/glaa097] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Indexed: 12/27/2022] Open
Abstract
Balance impairment and falls are among the most prevalent and morbid conditions affecting older adults. A critical contributor to balance and gait function is the vestibular system; however, there remain substantial knowledge gaps regarding age-related vestibular loss and its contribution to balance impairment and falls in older adults. Given these knowledge gaps, the National Institute on Aging and the National Institute on Deafness and Other Communication Disorders convened a multidisciplinary workshop in April 2019 that brought together experts from a wide array of disciplines, such as vestibular physiology, neuroscience, movement science, rehabilitation, and geriatrics. The goal of the workshop was to identify key knowledge gaps on vestibular function and balance control in older adults and develop a research agenda to make substantial advancements in the field. This article provides a report of the proceedings of this workshop. Three key questions emerged from the workshop, specifically: (i) How does aging impact vestibular function?; (ii) How do we know what is the contribution of age-related vestibular impairment to an older adult's balance problem?; and more broadly, (iii) Can we develop a nosology of balance impairments in older adults that can guide clinical practice? For each of these key questions, the current knowledge is reviewed, and the critical knowledge gaps and research strategies to address them are discussed. This document outlines an ambitious 5- to 10-year research agenda for increasing knowledge related to vestibular impairment and balance control in older adults, with the ultimate goal of linking this knowledge to more effective treatment.
Collapse
Affiliation(s)
- Yuri Agrawal
- Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Daniel M Merfeld
- Department of Otolaryngology-Head and Neck Surgery, Ohio State University, Columbus
| | - Fay B Horak
- Department of Neurology, School of Medicine, Oregon Health & Science University, Portland
| | - Mark S Redfern
- Department of Bioengineering, University of Pittsburgh, Pennsylvania
- Department of Otolaryngology, University of Pittsburgh, Pennsylvania
| | - Brad Manor
- Division of Gerontology, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts
- Harvard Medical School, Boston, Massachusetts
| | | | - Gay R Holstein
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Paul F Smith
- Department of Pharmacology and Toxicology, School of Medical Sciences, University of Otago, Dunedin, New Zealand
- Brain Research New Zealand, Dunedin, New Zealand
| | - Tanvi Bhatt
- Department of Physical Therapy, University of Illinois at Chicago
| | - Nicolaas I Bohnen
- Department of Neurology, University of Michigan, Ann Arbor
- Department of Radiology, University of Michigan, Ann Arbor
| | - Lewis A Lipsitz
- Division of Gerontology, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts
- Harvard Medical School, Boston, Massachusetts
| |
Collapse
|
2
|
Lu J, Hu L, Ye B, Hu H, Tao Y, Shu Y, Hao Chiang, Borse V, Xiang M, Wu H, Edge ASB, Shi F. Increased Type I and Decreased Type II Hair Cells after Deletion of Sox2 in the Developing Mouse Utricle. Neuroscience 2019; 422:146-160. [PMID: 31678344 PMCID: PMC10858341 DOI: 10.1016/j.neuroscience.2019.09.027] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2018] [Revised: 09/21/2019] [Accepted: 09/23/2019] [Indexed: 12/13/2022]
Abstract
The vestibular system of the inner ear contains Type I and Type II hair cells (HCs) generated from sensory progenitor cells; however, little is known about how the HC subtypes are formed. Sox2 (encoding SRY-box 2) is expressed in Type II, but not in Type I, HCs. The present study aimed to investigate the role of SOX2 in cell fate determination in Type I vs. Type II HCs. First, we confirmed that Type I HCs developed from Sox2-expressing cells through lineage tracing of Sox2-positive cells using a CAG-tdTomato reporter mouse crossed with a Sox2-CreER mouse. Then, Sox2 loss of function was induced in HCs, using Sox2flox transgenic mice crossed with a Gfi1-Cre driver mouse. Knockout of Sox2 in HCs increased the number of Type I HCs and decreased the number of Type II HCs, while the total number of HCs and Sox2-positive supporting cells did not change. In addition, the effect of Sox2-knockout persisted into adulthood, resulting in an increased number of Type I HCs. These results demonstrate that SOX2 plays a critical role in the determination of Type II vs. Type I HC fate. The results suggested that Sox2 is a potential target for generating Type I HCs, which may be important for regenerative strategies for balance disorders.
Collapse
Affiliation(s)
- Jingrong Lu
- Department of Otolaryngology-Head & Neck Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200092, China; Ear Institute, Shanghai Jiaotong University School of Medicine, Shanghai 200092, China; Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, China
| | - Lingxiang Hu
- Ear Institute, Shanghai Jiaotong University School of Medicine, Shanghai 200092, China; Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, China; Department of Otolaryngology Head & Neck Surgery, Shanghai 9th People's Hospital/Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200092, China
| | - Bin Ye
- Department of Otolaryngology-Head & Neck Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200092, China; Ear Institute, Shanghai Jiaotong University School of Medicine, Shanghai 200092, China; Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, China
| | - Haixia Hu
- Department of Otolaryngology-Head & Neck Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200092, China; Ear Institute, Shanghai Jiaotong University School of Medicine, Shanghai 200092, China; Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, China
| | - Yong Tao
- Ear Institute, Shanghai Jiaotong University School of Medicine, Shanghai 200092, China; Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, China; Department of Otolaryngology Head & Neck Surgery, Shanghai 9th People's Hospital/Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200092, China
| | - Yilai Shu
- ENT Institute and Otorhinolaryngology Department, Affiliated Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China; Key Laboratory of Hearing Medicine of National Health and Family Planning Commission (NHFPC), Shanghai, China
| | - Hao Chiang
- Department of Otolaryngology, Harvard Medical School, Boston, MA 02115, USA; Eaton-Peabody Laboratory, Massachusetts Eye and Ear, Boston, MA 02114, USA
| | - Vikrant Borse
- Department of Otolaryngology, Harvard Medical School, Boston, MA 02115, USA; Eaton-Peabody Laboratory, Massachusetts Eye and Ear, Boston, MA 02114, USA
| | - Mingliang Xiang
- Department of Otolaryngology-Head & Neck Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200092, China; Ear Institute, Shanghai Jiaotong University School of Medicine, Shanghai 200092, China; Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, China
| | - Hao Wu
- Ear Institute, Shanghai Jiaotong University School of Medicine, Shanghai 200092, China; Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, China; Department of Otolaryngology Head & Neck Surgery, Shanghai 9th People's Hospital/Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200092, China.
| | - Albert S B Edge
- Department of Otolaryngology, Harvard Medical School, Boston, MA 02115, USA; Eaton-Peabody Laboratory, Massachusetts Eye and Ear, Boston, MA 02114, USA
| | - Fuxin Shi
- Ear Institute, Shanghai Jiaotong University School of Medicine, Shanghai 200092, China; Decibel Therapeutics, Boston, MA 02215, USA.
| |
Collapse
|
3
|
Wang T, Niwa M, Sayyid ZN, Hosseini DK, Pham N, Jones SM, Ricci AJ, Cheng AG. Uncoordinated maturation of developing and regenerating postnatal mammalian vestibular hair cells. PLoS Biol 2019; 17:e3000326. [PMID: 31260439 PMCID: PMC6602158 DOI: 10.1371/journal.pbio.3000326] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2018] [Accepted: 05/30/2019] [Indexed: 11/18/2022] Open
Abstract
Sensory hair cells are mechanoreceptors required for hearing and balance functions. From embryonic development, hair cells acquire apical stereociliary bundles for mechanosensation, basolateral ion channels that shape receptor potential, and synaptic contacts for conveying information centrally. These key maturation steps are sequential and presumed coupled; however, whether hair cells emerging postnatally mature similarly is unknown. Here, we show that in vivo postnatally generated and regenerated hair cells in the utricle, a vestibular organ detecting linear acceleration, acquired some mature somatic features but hair bundles appeared nonfunctional and short. The utricle consists of two hair cell subtypes with distinct morphological, electrophysiological and synaptic features. In both the undamaged and damaged utricle, fate-mapping and electrophysiology experiments showed that Plp1+ supporting cells took on type II hair cell properties based on molecular markers, basolateral conductances and synaptic properties yet stereociliary bundles were absent, or small and nonfunctional. By contrast, Lgr5+ supporting cells regenerated hair cells with type I and II properties, representing a distinct hair cell precursor subtype. Lastly, direct physiological measurements showed that utricular function abolished by damage was partially regained during regeneration. Together, our data reveal a previously unrecognized aberrant maturation program for hair cells generated and regenerated postnatally and may have broad implications for inner ear regenerative therapies. During development, sensory hair cells undergo a series of critical maturation steps that are sequential and presumed coupled, but whether regenerated hair cells mature similarly is unknown. This study shows that regenerated vestibular hair cells acquired some mature somatic features, but the apical bundles remained immature.
Collapse
Affiliation(s)
- Tian Wang
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, California, United States of America
- Department of Otolaryngology-Head and Neck Surgery, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Mamiko Niwa
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, California, United States of America
| | - Zahra N. Sayyid
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, California, United States of America
| | - Davood K. Hosseini
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, California, United States of America
| | - Nicole Pham
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, California, United States of America
| | - Sherri M. Jones
- Department of Special Education and Communication Disorders, College of Education and Human Sciences, University of Nebraska, Lincoln, Nebraska, United States of America
| | - Anthony J. Ricci
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, California, United States of America
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, California, United States of America
- * E-mail: (AGC); (AJR)
| | - Alan G. Cheng
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, California, United States of America
- * E-mail: (AGC); (AJR)
| |
Collapse
|
4
|
Khan SI, Hübner PP, Brichta AM, Smith DW, Migliaccio AA. Aging reduces the high-frequency and short-term adaptation of the vestibulo-ocular reflex in mice. Neurobiol Aging 2017; 51:122-131. [PMID: 28063365 DOI: 10.1016/j.neurobiolaging.2016.12.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Revised: 12/08/2016] [Accepted: 12/09/2016] [Indexed: 12/20/2022]
Affiliation(s)
- Serajul I Khan
- Balance and Vision Laboratory, Neuroscience Research Australia, Sydney, New South Wales, Australia; University of New South Wales, Sydney, New South Wales, Australia
| | - Patrick P Hübner
- Balance and Vision Laboratory, Neuroscience Research Australia, Sydney, New South Wales, Australia; University of New South Wales, Sydney, New South Wales, Australia
| | - Alan M Brichta
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Newcastle, Australia
| | - Doug W Smith
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Newcastle, Australia
| | - Americo A Migliaccio
- Balance and Vision Laboratory, Neuroscience Research Australia, Sydney, New South Wales, Australia; University of New South Wales, Sydney, New South Wales, Australia; Department of Otolaryngology - Head and Neck Surgery, Johns Hopkins University, Baltimore, MD, USA.
| |
Collapse
|
5
|
Liu P, Gupta N, Jing Y, Collie ND, Zhang H, Smith PF. Further studies of the effects of aging on arginine metabolites in the rat vestibular nucleus and cerebellum. Neuroscience 2017; 348:273-287. [PMID: 28238850 DOI: 10.1016/j.neuroscience.2017.02.033] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 02/16/2017] [Accepted: 02/16/2017] [Indexed: 12/21/2022]
Abstract
Some studies have demonstrated that aging is associated with impaired vestibular reflexes, especially otolithic reflexes, resulting in postural instability. However, the neurochemical basis of these age-related changes is still poorly understood. The l-arginine metabolic system has been implicated in changes in the brain associated with aging. In the current study, we examined the levels of l-arginine and its metabolizing enzymes and downstream metabolites in the vestibular nucleus complex (VNC) and cerebellum (CE) of rats with and without behavioral testing which were young (4months old), middle-aged (12months old) or aged (24months old). We found that aging was associated with lower nitric oxide synthase activity in the CE of animals with testing and increased arginase in the VNC and CE of animals with testing. l-citrulline and l-ornithine were lower in the VNC of aged animals irrespective of testing, while l-arginine and l-citrulline were lower in the CE with and without testing, respectively. In the VNC and CE, aging was associated with lower levels of glutamate in the VNC, irrespective of testing. In the VNC it was associated with higher levels of agmatine and putrescine, irrespective of testing. In the CE, aging was associated with higher levels of putrescine in animals without testing and with higher levels of spermine in animals with testing, and spermidine, irrespective of testing. Multivariate analyses indicated significant predictive relationships between the different variables, and there were correlations between some of the neurochemical variables and behavioral measurements. Cluster analyses revealed that aging altered the relationships between l-arginine and its metabolites. The results of this study demonstrate that there are major changes occurring in l-arginine metabolism in the VNC and CE as a result of age, as well as behavioral activity.
Collapse
Affiliation(s)
- P Liu
- Dept. of Anatomy, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand; Brain Health Research Centre, University of Otago, Dunedin, New Zealand; The Brain Research New Zealand Centre of Research Excellence, New Zealand.
| | - N Gupta
- Dept. of Anatomy, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand; Brain Health Research Centre, University of Otago, Dunedin, New Zealand
| | - Y Jing
- Dept. of Anatomy, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand; Brain Health Research Centre, University of Otago, Dunedin, New Zealand
| | - N D Collie
- Dept. of Anatomy, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand; Brain Health Research Centre, University of Otago, Dunedin, New Zealand
| | - H Zhang
- School of Pharmacy, University of Otago, Dunedin, New Zealand; Brain Health Research Centre, University of Otago, Dunedin, New Zealand
| | - P F Smith
- Dept. of Pharmacology and Toxicology, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand; Brain Health Research Centre, University of Otago, Dunedin, New Zealand; The Brain Research New Zealand Centre of Research Excellence, New Zealand; The Eisdell Moore Centre, University of Auckland, New Zealand
| |
Collapse
|
6
|
Usman HO, Balaban CD. Distribution of 5-HT 1F Receptors in Monkey Vestibular and Trigeminal Ganglion Cells. Front Neurol 2016; 7:173. [PMID: 27777567 PMCID: PMC5056317 DOI: 10.3389/fneur.2016.00173] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Accepted: 09/27/2016] [Indexed: 01/03/2023] Open
Abstract
Background Evidence of serotonergic involvement in vestibular pathway contributions to migraine and balance disorders is compelling. Serotonergic 5-HT1B and 5-HT1D receptors are expressed extensively in inner ear ganglia of monkeys and rats. The serotonergic 5-HT1F receptor is also a target of triptans. This study describes its distribution in vestibular and trigeminal ganglia of monkeys. Methods Using primary polyclonal antibodies raised against oligopeptides specific for the human 5-HT1F receptor, neuronal somatic area and intensity of immunoreactive vestibular and trigeminal ganglia were quantified. Results and Discussion Virtually all vestibular and considerable trigeminal ganglia showed positive 5-HT1F receptor immunoreactivity. Inferior and superior vestibular ganglia staining appeared confined to distinct cell regions, varying considerably among cells of different sizes: more intense in small, punctate in some medium and regionally polarized in some large cells. Analyses of average somatic vestibular neuronal immunoreactive intensity identified mainly medium sized cells with high standard deviation of intensity corresponding to punctately stained cells. Less variability occurred in somatic intensity staining and cellular distribution among 5-HT1F receptor immunopositive trigeminal ganglia. Most exhibited similar punctate staining patterns, higher mean somatic immunoreactive intensity and larger neuronal somatic size proportions per size distribution subpopulation compared to vestibular ganglia size distribution populations. Centrally directed vestibular ganglion neuronal processes, cochlear inner hair cells, vestibular hair cells and blood vessels in vestibular maculae and cristae were immunoreactive. The 5-HT1F receptor expression in vestibular ganglia shows complex variable staining intensity patterns associated with cell size of immunopositive neurons, not seen in immunopositive trigeminal ganglia and not previously evident with 5-HT1B and 5-HT1D receptor subtype immunoreactivity in vestibular ganglia. These data motivate exploration of 5-HT1 receptor oligomerization and ligand functional selectivity in differential serotonergic involvement in co-morbidity of migraine and balance disorders. Similar findings in cochlear inner hair cell afferents are applicable to migraine-related tinnitus or hypercusis (phonophobia).
Collapse
Affiliation(s)
- Habiba O Usman
- Department of Otolaryngology, University of Pittsburgh , Pittsburgh, PA , USA
| | - Carey D Balaban
- Department of Otolaryngology, University of Pittsburgh, Pittsburgh, PA, USA; Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA, USA; Department of Communication Sciences and Disorders, University of Pittsburgh, Pittsburgh, PA, USA; Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
| |
Collapse
|
7
|
Smith PF. Age-Related Neurochemical Changes in the Vestibular Nuclei. Front Neurol 2016; 7:20. [PMID: 26973593 PMCID: PMC4776078 DOI: 10.3389/fneur.2016.00020] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 02/09/2016] [Indexed: 12/18/2022] Open
Abstract
There is evidence that the normal aging process is associated with impaired vestibulo-ocular reflexes (VOR) and vestibulo-spinal reflexes, causing reduced visual acuity and postural instability. Nonetheless, the available evidence is not entirely consistent, especially with respect to the VOR. Some recent studies have reported that VOR gain can be intact even above 80 years of age. Similarly, although there is evidence for age-related hair cell loss and neuronal loss in Scarpa's ganglion and the vestibular nucleus complex (VNC), it is not entirely consistent. Whatever structural and functional changes occur in the VNC as a result of aging, either to cause vestibular impairment or to compensate for it, neurochemical changes must underlie them. However, the neurochemical changes that occur in the VNC with aging are poorly understood because the available literature is very limited. This review summarizes and critically evaluates the available evidence relating to the noradrenaline, serotonin, dopamine, glutamate, GABA, glycine, and nitric oxide neurotransmitter systems in the aging VNC. It is concluded that, at present, it is difficult, if not impossible, to relate the neurochemical changes observed to the function of specific VNC neurons and whether the observed changes are the cause of a functional deficit in the VNC or an effect of it. A better understanding of the neurochemical changes that occur during aging may be important for the development of potential drug treatments for age-related vestibular disorders. However, this will require the use of more sophisticated methodology such as in vivo microdialysis with single neuron recording and perhaps new technologies such as optogenetics.
Collapse
Affiliation(s)
- Paul F Smith
- Department of Pharmacology and Toxicology, School of Medical Sciences and Brain Health Research Centre, University of Otago , Dunedin , New Zealand
| |
Collapse
|
8
|
Simmons DD, Tong B, Schrader AD, Hornak AJ. Oncomodulin identifies different hair cell types in the mammalian inner ear. J Comp Neurol 2010; 518:3785-802. [PMID: 20653034 DOI: 10.1002/cne.22424] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The tight regulation of Ca(2+) is essential for inner ear function, and yet the role of Ca(2+) binding proteins (CaBPs) remains elusive. By using immunofluorescence and reverse transcriptase-polymerase chain reaction (RT-PCR), we investigated the expression of oncomodulin (Ocm), a member of the parvalbumin family, relative to other EF-hand CaBPs in cochlear and vestibular organs in the mouse. In the mouse cochlea, Ocm is found only in outer hair cells and is localized preferentially to the basolateral outer hair cell membrane and to the base of the hair bundle. Developmentally, Ocm immunoreactivity begins as early as postnatal day (P) 2 and shows preferential localization to the basolateral membrane and hair bundle after P8. Unlike the cochlea, Ocm expression is substantially reduced in vestibular tissues at older adult ages. In vestibular organs, Ocm is found in type I striolar or central hair cells, and has a more diffuse subcellular localization throughout the hair cell body. Additionally, Ocm immunoreactivity in vestibular hair cells is present as early as E18 and is not obviously affected by mutations that cause a disruption of hair bundle polarity. We also find Ocm expression in striolar hair cells across mammalian species. These data suggest that Ocm may have distinct functional roles in cochlear and vestibular hair cells.
Collapse
Affiliation(s)
- Dwayne D Simmons
- Department of Integrative Biology and Physiology and the Brain Research Institute, University of California Los Angeles, Los Angeles, California 90095, USA.
| | | | | | | |
Collapse
|
9
|
Liu P, Zhang H, Devaraj R, Ganesalingam GS, Smith PF. A multivariate analysis of the effects of aging on glutamate, GABA and arginine metabolites in the rat vestibular nucleus. Hear Res 2010; 269:122-33. [DOI: 10.1016/j.heares.2010.06.019] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2010] [Revised: 06/21/2010] [Accepted: 06/22/2010] [Indexed: 01/21/2023]
|
10
|
Avallone B, Fascio U, Balsamo G, Bianco PG, Balassone G, Marmo F. Morphogenesis of otoliths during larval development in brook lamprey,Lampetra planeri. ACTA ACUST UNITED AC 2007. [DOI: 10.1080/11250000701459301] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
11
|
Leonard RB, Kevetter GA. Structural and functional changes in the cristae ampullares of aged gerbils. Neuroscience 2007; 147:794-802. [PMID: 17561351 DOI: 10.1016/j.neuroscience.2007.05.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2007] [Revised: 04/17/2007] [Accepted: 05/03/2007] [Indexed: 10/23/2022]
Abstract
We have reported that calretinin and calbindin staining of calyxes in the apical region of the cristae is reduced or absent in old gerbils (>or=35 months) that had normal numbers of hair cells [Kevetter GA, Leonard RB (2002) Decreased expression of calretinin and calbindin in the labyrinth of old gerbils. Brain Res 957:362-365]. Here we examine the ability of primary afferents in aged gerbils to carry a tracer injected into the vestibular nuclear complex to their terminals in the cristae. Calyxes throughout the cristae were well labeled in a young animal with such an injection. In the aged animals, many calyxes were only partially filled or not filled at all. In some cases labeled axons were also missing from the stroma underlying the missing calyxes. There is a strong correspondence between the region where the calyxes were not filled and the absence of calretinin immunostaining. To determine if afferents from the cristae are functionally abnormal, we recorded from their axons and attempted to activate them with natural stimulation. Among afferents that could be activated, we encountered many afferents that had spontaneous activity but could not be modulated with natural stimulation. When tested, the firing rate of these afferents could be modulated with galvanic stimulation, and/or they could be activated by pulsed electrical stimulation. We also encountered afferents that had no spontaneous activity. The presence of these axons was revealed by an injury discharge that could not be modulated with natural stimulation. When tested, these axons could be activated with pulsed electrical stimulation. In some instances we encountered two or more such afferents in a row, an event we have not seen in young animals. We suggest that the simplest explanation for these observations is that calyxes are being lost in old animals.
Collapse
Affiliation(s)
- R B Leonard
- Departments of Neuroscience and Cell Biology and Otolaryngology, University of Texas Medical Branch, Galveston, TX 77555-1069, USA.
| | | |
Collapse
|
12
|
Kevetter GA, Zimmerman CL, Leonard RB. Hair cell numbers do not decrease in the crista ampullaris of geriatric gerbils. J Neurosci Res 2005; 80:279-85. [PMID: 15765526 DOI: 10.1002/jnr.20451] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Among the geriatric population, dizziness and falling are serious problems. One system involved in balance that may change with age is the vestibular system. A common assertion is that the number of vestibular hair cells decreases as age increases. Our goal was to quantitate the number of hair cells in young and old gerbils and document the decrease. We used physical dissector design-based stereological procedures on serial 2-microm sections through the crista ampullaris. Between young and aged gerbils, there were no quantitative differences in the number, density, or types of hair cells or the length of the crista ampullaris. This lack of change in the number of hair cells suggests that the cause for vestibular dysfunction during aging must lie elsewhere.
Collapse
Affiliation(s)
- Golda Anne Kevetter
- Department of Otolaryngology, The University of Texas Medical Branch, Galveston, Texas 77555-1063, USA.
| | | | | |
Collapse
|