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Accomando AW, Johnson MA, McLaughlin MA, Simmons JA, Simmons AM. Connexin36 RNA Expression in the Cochlear Nucleus of the Echolocating Bat, Eptesicus fuscus. J Assoc Res Otolaryngol 2023; 24:281-290. [PMID: 37253961 PMCID: PMC10335991 DOI: 10.1007/s10162-023-00898-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Accepted: 03/30/2023] [Indexed: 06/01/2023] Open
Abstract
PURPOSE The echolocating bat is used as a model for studying the auditory nervous system because its specialized sensory capabilities arise from general mammalian auditory percepts such as pitch and sound source localization. These percepts are mediated by precise timing within neurons and networks of the lower auditory brainstem, where the gap junction protein Connexin36 (CX36) is expressed. Gap junctions and electrical synapses in the central nervous system are associated with fast transmission and synchronous patterns of firing within neuronal networks. The purpose of this study was to identify areas where CX36 was expressed in the bat cochlear nucleus to shed light on auditory brainstem networks in a hearing specialist animal model. METHODS We investigated the distribution of CX36 RNA throughout the cochlear nucleus complex of the echolocating big brown bat, Eptesicus fuscus, using in situ hybridization. As a qualitative comparison, we visualized Gjd2 gene expression in the cochlear nucleus of transgenic CX36 reporter mice, species that hear ultrasound but do not echolocate. RESULTS In both the bat and the mouse, CX36 is expressed in the anteroventral and in the dorsal cochlear nucleus, with more limited expression in the posteroventral cochlear nucleus. These results are generally consistent with previous work based on immunohistochemistry. CONCLUSION Our data suggest that the anatomical substrate for CX36-mediated electrical neurotransmission is conserved in the mammalian CN across echolocating bats and non-echolocating mice.
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Affiliation(s)
- Alyssa W. Accomando
- Division of Biology and Medicine, Department of Neuroscience, Brown University, Providence, RI 02912 USA
| | - Mark A. Johnson
- Division of Biology and Medicine, Department of Neuroscience, Brown University, Providence, RI 02912 USA
- Taconic Biosciences, Rensselaer, NY 12144 USA
| | - Madeline A. McLaughlin
- Division of Biology and Medicine, Department of Neuroscience, Brown University, Providence, RI 02912 USA
| | - James A. Simmons
- Division of Biology and Medicine, Department of Neuroscience, Brown University, Providence, RI 02912 USA
- Carney Institute for Brain Science, Brown University, Providence, RI 02912 USA
| | - Andrea Megela Simmons
- Division of Biology and Medicine, Department of Neuroscience, Brown University, Providence, RI 02912 USA
- Carney Institute for Brain Science, Brown University, Providence, RI 02912 USA
- Department of Cognitive, Linguistic, and Psychological Sciences, Brown University, Providence, RI 02912 USA
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Tan J, Li Y, Gao D, Sun L, Song Q, Yang J. A liquid chromatography-mass spectroscopy-based untargeted metabolomic study of the rat cochlear nucleus at various stages of maturity. Hear Res 2022; 426:108645. [DOI: 10.1016/j.heares.2022.108645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 10/12/2022] [Accepted: 11/01/2022] [Indexed: 11/08/2022]
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Sánchez-Benito D, Hyppolito MA, Alvarez-Morujo AJ, López DE, Gómez-Nieto R. Morphological and molecular correlates of altered hearing sensitivity in the genetically audiogenic seizure-prone hamster GASH/Sal. Hear Res 2020; 392:107973. [PMID: 32402894 DOI: 10.1016/j.heares.2020.107973] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 03/30/2020] [Accepted: 04/07/2020] [Indexed: 02/08/2023]
Abstract
Rodent models of audiogenic seizures, in which seizures are precipitated by an abnormal response of the brain to auditory stimuli, are crucial to investigate the neural bases underlying ictogenesis. Despite significant advances in understanding seizure generation in the inferior colliculus, namely the epileptogenic nucleus, little is known about the contribution of lower auditory stations to the seizure-prone network. Here, we examined the cochlea and cochlear nucleus of the genetic audiogenic seizure hamster from Salamanca (GASH/Sal), a model of reflex epilepsy that exhibits generalized tonic-clonic seizures in response to loud sound. GASH/Sal animals under seizure-free conditions were compared with matched control hamsters in a multi-technical approach that includes auditory brainstem responses (ABR) testing, histology, scanning electron microscopy analysis, immunohistochemistry, quantitative morphometry and gene expression analysis (RT-qPCR). The cochlear histopathology of the GASH/Sal showed preservation of the sensory hair cells, but a significant loss of spiral ganglion neurons and mild atrophy of the stria vascularis. At the electron microscopy level, the reticular lamina exhibited disarray of stereociliary tufts with blebs, loss or elongated stereocilia as well as non-parallel rows of outer hair cells due to protrusions of Deiters' cells. At the molecular level, the abnormal gene expression patterns of prestin, cadherin 23, protocadherin 15, vesicular glutamate transporters 1 (Vglut1) and -2 (Vglut2) indicated that the hair-cell mechanotransduction and cochlear amplification were markedly altered. These were manifestations of a cochlear neuropathy that correlated to ABR waveform I alterations and elevated auditory thresholds. In the cochlear nucleus, the distribution of VGLUT2-immunolabeled puncta was differently affected in each subdivision, showing significant increases in magnocellular regions of the ventral cochlear nucleus and drastic reductions in the granule cell domain. This modified inputs lead to disruption of Vglut1 and Vglut2 gene expression in the cochlear nucleus. In sum, our study provides insight into the morphological and molecular traits associated with audiogenic seizure susceptibility in the GASH/Sal, suggesting an upward spread of abnormal glutamatergic transmission throughout the primary acoustic pathway to the epileptogenic region.
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Affiliation(s)
- David Sánchez-Benito
- Institute of Neuroscience of Castilla y León (INCYL), University of Salamanca, Salamanca, Spain; Institute of Biomedical Research of Salamanca (IBSAL), University of Salamanca, Salamanca, Spain
| | - Miguel A Hyppolito
- Laboratory of Neurobiology of Hearing, Department of Ophthalmology, Otorhinolaryngology, Head and Neck Surgery, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil
| | - Antonio J Alvarez-Morujo
- Institute of Neuroscience of Castilla y León (INCYL), University of Salamanca, Salamanca, Spain; Institute of Biomedical Research of Salamanca (IBSAL), University of Salamanca, Salamanca, Spain; Department of Human Anatomy and Histology, Faculty of Medicine, University of Salamanca, Salamanca, Spain
| | - Dolores E López
- Institute of Neuroscience of Castilla y León (INCYL), University of Salamanca, Salamanca, Spain; Institute of Biomedical Research of Salamanca (IBSAL), University of Salamanca, Salamanca, Spain; Department of Cell Biology and Pathology, Faculty of Medicine, University of Salamanca, Salamanca, Spain
| | - Ricardo Gómez-Nieto
- Institute of Neuroscience of Castilla y León (INCYL), University of Salamanca, Salamanca, Spain; Institute of Biomedical Research of Salamanca (IBSAL), University of Salamanca, Salamanca, Spain; Department of Cell Biology and Pathology, Faculty of Medicine, University of Salamanca, Salamanca, Spain.
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Godfrey DA, Mikesell NL, Godfrey TG, Kaltenbach JA. Amino acid and acetylcholine chemistry in mountain beaver cochlear nucleus and comparisons to pocket gopher, other rodents, and cat. Hear Res 2019; 385:107841. [PMID: 31765816 DOI: 10.1016/j.heares.2019.107841] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 10/16/2019] [Accepted: 11/06/2019] [Indexed: 11/17/2022]
Abstract
The mountain beaver and pocket gopher are two rodents that live mostly underground in tunnel systems. Previous studies have suggested that their cochlear nucleus structure, particularly that of the dorsal cochlear nucleus (DCN), differs significantly from that of other mammals, that the hearing ability of the pocket gopher is deficient compared to that of other rodents, and that the DCN of the mountain beaver is more responsive to slow oscillations of air pressure than to sounds. We conducted some electrophysiological recordings from mountain beaver DCN and then used microchemical methods to map in mountain beaver cochlear nuclei the distributions of amino acids, including the major neurotransmitters of the brain, and enzyme activities related to the metabolism of the neurotransmitter acetylcholine, which functions in centrifugal pathways to the cochlear nucleus. Similar measurements were made for a pocket gopher cochlear nucleus. Responses to tonal stimuli were found in mountain beaver DCN. Distributions and magnitudes of neurotransmitter and related amino acids within mountain beaver and pocket gopher cochlear nuclei were not very different from those of other rodents and cat. However, the enzyme of synthesis for acetylcholine, choline acetyltransferase, had only low activities in the DCN of both mountain beaver and pocket gopher. The chemical distributions in the mountain beaver DCN support a conclusion that it corresponds to just the superficial DCN portion of other mammals. High correlations between the concentrations of γ-aminobutyrate (GABA) and glycine were found for both mountain beaver and pocket gopher cochlear nuclei, suggesting that their co-localization in cochlear nucleus synapses may be especially prominent in these animals. Previous evidence suggests convergence of somatosensory and auditory information in the DCN, and this may be especially true in animals spending most of their time underground. Our results suggest that the enlarged DCN of the mountain beaver and that of the pocket gopher are not very different from those of other rodents with respect to involvement of amino acid neurotransmitters, but they appear to have reduced cholinergic innervation.
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Affiliation(s)
- Donald A Godfrey
- Department of Neurology and Division of Otolaryngology and Dentistry, Department of Surgery, University of Toledo College of Medicine and Life Sciences, Toledo, OH, USA.
| | - Nikki L Mikesell
- Department of Neurology and Division of Otolaryngology and Dentistry, Department of Surgery, University of Toledo College of Medicine and Life Sciences, Toledo, OH, USA
| | - Timothy G Godfrey
- Department of Neurology and Division of Otolaryngology and Dentistry, Department of Surgery, University of Toledo College of Medicine and Life Sciences, Toledo, OH, USA
| | - James A Kaltenbach
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
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Waxholm Space atlas of the rat brain auditory system: Three-dimensional delineations based on structural and diffusion tensor magnetic resonance imaging. Neuroimage 2019; 199:38-56. [DOI: 10.1016/j.neuroimage.2019.05.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2019] [Revised: 05/01/2019] [Accepted: 05/06/2019] [Indexed: 12/14/2022] Open
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Dollas A, Oelschläger HHA, Begall S, Burda H, Malkemper EP. Brain atlas of the African mole-rat Fukomys anselli. J Comp Neurol 2019; 527:1885-1900. [PMID: 30697737 PMCID: PMC6593805 DOI: 10.1002/cne.24647] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 12/21/2018] [Accepted: 12/26/2018] [Indexed: 11/06/2022]
Abstract
African mole-rats are subterranean rodents that spend their whole life in underground burrow systems. They show a range of morphological and physiological adaptations to their ecotope, for instance severely reduced eyes and specialized somatosensory, olfactory, and auditory systems. These adaptations are also reflected in the accessory sensory pathways in the brain that process the input coming from the sensory organs. So far, a brain atlas was available only for the naked mole-rat (Heterocephalus glaber). The Ansell's mole-rat (Fukomys anselli) has been the subject of many investigations in various disciplines (ethology, sensory physiology, and anatomy) including magnetic orientation. It is therefore surprising that an atlas of the brain of this species was not available so far. Here, we present a comprehensive atlas of the Ansell's mole-rat brain based on Nissl and Klüver-Barrera stained sections. We identify and label 375 brain regions and discuss selected differences from the brain of the closely related naked mole-rat as well as from epigeic mammals (rat), with a particular focus on the auditory brainstem. This atlas can serve as a reference for future neuroanatomical investigations of subterranean mammals.
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Affiliation(s)
- Alexa Dollas
- Department of General Zoology, Faculty of BiologyUniversity of Duisburg‐EssenEssenGermany
| | - Helmut H. A. Oelschläger
- Department of Anatomy III (Dr. Senckenbergische Anatomie), Medical FacultyJohann Wolfgang Goethe UniversityFrankfurtGermany
| | - Sabine Begall
- Department of General Zoology, Faculty of BiologyUniversity of Duisburg‐EssenEssenGermany
- Department of Game Management and Wildlife BiologyFaculty of Forestry and Wood Sciences, Czech University of Life SciencesPraha 6Czech Republic
| | - Hynek Burda
- Department of General Zoology, Faculty of BiologyUniversity of Duisburg‐EssenEssenGermany
- Department of Game Management and Wildlife BiologyFaculty of Forestry and Wood Sciences, Czech University of Life SciencesPraha 6Czech Republic
| | - Erich Pascal Malkemper
- Department of General Zoology, Faculty of BiologyUniversity of Duisburg‐EssenEssenGermany
- Research Institute of Molecular Pathology (IMP)Vienna Biocenter (VBC), Campus‐Vienna‐Biocenter 1Vienna 1030Austria
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Calderón-Garcidueñas L, González-González LO, Kulesza RJ, Fech TM, Pérez-Guillé G, Luna MAJB, Soriano-Rosales RE, Solorio E, Miramontes-Higuera JDJ, Gómez-Maqueo Chew A, Bernal-Morúa AF, Mukherjee PS, Torres-Jardón R, Mills PC, Wilson WJ, Pérez-Guillé B, D'Angiulli A. Exposures to fine particulate matter (PM 2.5) and ozone above USA standards are associated with auditory brainstem dysmorphology and abnormal auditory brainstem evoked potentials in healthy young dogs. ENVIRONMENTAL RESEARCH 2017; 158:324-332. [PMID: 28672130 DOI: 10.1016/j.envres.2017.06.026] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2017] [Revised: 05/29/2017] [Accepted: 06/22/2017] [Indexed: 06/07/2023]
Abstract
BACKGROUND Delayed central conduction times in the auditory brainstem have been observed in Mexico City (MC) healthy children exposed to fine particulate matter (PM2.5) and ozone (O3) above the current United States Environmental Protection Agency (US-EPA) standards. MC children have α synuclein brainstem accumulation and medial superior olivary complex (MSO) dysmorphology. The present study used a dog model to investigate the potential effects of air pollution on the function and morphology of the auditory brainstem. METHODOLOGY Twenty-four dogs living in clean air v MC, average age 37.1 ± 26.3 months, underwent brainstem auditory evoked potential (BAEP) measurements. Eight dogs (4 MC, 4 Controls) were analysed for auditory brainstem morphology and histopathology. RESULTS MC dogs showed ventral cochlear nuclei hypotrophy and MSO dysmorphology with a significant decrease in cell body size, decreased neuronal packing density with regions in the nucleus devoid of neurons and marked gliosis. MC dogs showed significant delayed BAEP absolute wave I, III and V latencies compared to controls. CONCLUSIONS MC dogs show auditory nuclei dysmorphology and BAEPs consistent with an alteration of the generator sites of the auditory brainstem response waveform. This study puts forward the usefulness of BAEPs to study auditory brainstem neurodegenerative changes associated with air pollution in dogs. Recognition of the role of non-invasive BAEPs in urban dogs is warranted to elucidate novel neurodegenerative pathways link to air pollution and a promising early diagnostic strategy for Alzheimer's Disease.
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Affiliation(s)
| | | | - Randy J Kulesza
- Auditory Research Center, Lake Erie College of Osteopathic Medicine, Erie, PA 16509, USA
| | - Tatiana M Fech
- Auditory Research Center, Lake Erie College of Osteopathic Medicine, Erie, PA 16509, USA
| | | | | | | | | | | | | | | | | | - Ricardo Torres-Jardón
- Centro de Ciencias de la Atmósfera, Universidad Nacional Autónoma de México, Mexico City 04510, Mexico
| | - Paul C Mills
- The University of Queensland, QLD 4072, Australia
| | | | | | - Amedeo D'Angiulli
- Department of Psychology, Carleton University, Ottawa, Ontario, Canada K1S 5B6
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