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Williams IR, Ryugo DK. Bilateral and symmetric glycinergic and glutamatergic projections from the LSO to the IC in the CBA/CaH mouse. Front Neural Circuits 2024; 18:1430598. [PMID: 39184455 PMCID: PMC11341401 DOI: 10.3389/fncir.2024.1430598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2024] [Accepted: 07/10/2024] [Indexed: 08/27/2024] Open
Abstract
Auditory space has been conceptualized as a matrix of systematically arranged combinations of binaural disparity cues that arise in the superior olivary complex (SOC). The computational code for interaural time and intensity differences utilizes excitatory and inhibitory projections that converge in the inferior colliculus (IC). The challenge is to determine the neural circuits underlying this convergence and to model how the binaural cues encode location. It has been shown that midbrain neurons are largely excited by sound from the contralateral ear and inhibited by sound leading at the ipsilateral ear. In this context, ascending projections from the lateral superior olive (LSO) to the IC have been reported to be ipsilaterally glycinergic and contralaterally glutamatergic. This study used CBA/CaH mice (3-6 months old) and applied unilateral retrograde tracing techniques into the IC in conjunction with immunocytochemical methods with glycine and glutamate transporters (GlyT2 and vGLUT2, respectively) to analyze the projection patterns from the LSO to the IC. Glycinergic and glutamatergic neurons were spatially intermixed within the LSO, and both types projected to the IC. For GlyT2 and vGLUT2 neurons, the average percentage of ipsilaterally and contralaterally projecting cells was similar (ANOVA, p = 0.48). A roughly equal number of GlyT2 and vGLUT2 neurons did not project to the IC. The somatic size and shape of these neurons match the descriptions of LSO principal cells. A minor but distinct population of small (< 40 μm2) neurons that labeled for GlyT2 did not project to the IC; these cells emerge as candidates for inhibitory local circuit neurons. Our findings indicate a symmetric and bilateral projection of glycine and glutamate neurons from the LSO to the IC. The differences between our results and those from previous studies suggest that species and habitat differences have a significant role in mechanisms of binaural processing and highlight the importance of research methods and comparative neuroscience. These data will be important for modeling how excitatory and inhibitory systems converge to create auditory space in the CBA/CaH mouse.
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Affiliation(s)
- Isabella R. Williams
- Garvan Institute of Medical Research, Darlinghurst, NSW, Australia
- School of Medical Sciences, University of New South Wales, Kensington, NSW, Australia
| | - David K. Ryugo
- Garvan Institute of Medical Research, Darlinghurst, NSW, Australia
- School of Medical Sciences, University of New South Wales, Kensington, NSW, Australia
- Department of Otolaryngology, Head, Neck and Skull Base Surgery, St. Vincent’s Hospital, Darlinghurst, NSW, Australia
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2
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Manley GA, Maat B, Begall S, Malkemper P, Caspar KR, Moritz L, van Dijk P. Otoacoustic emissions in African mole-rats. Hear Res 2024; 445:108994. [PMID: 38520899 DOI: 10.1016/j.heares.2024.108994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 03/11/2024] [Accepted: 03/13/2024] [Indexed: 03/25/2024]
Abstract
African mole-rats display highly derived hearing that is characterized by low sensitivity and a narrow auditory range restricted to low frequencies < 10 kHz. Recently, it has been suggested that two species of these rodents do not exhibit distortion product otoacoustic emissions (DPOAE), which was interpreted as evidence for a lack of cochlear amplification. If true, this would make them unique among mammals. However, both theoretical considerations on the generation of DPOAE as well as previously published experimental evidence challenge this assumption. We measured DPOAE and stimulus-frequency otoacoustic emissions (SFOAE) in three species of African mole-rats (Ansell's mole-rat - Fukomys anselli; Mashona mole-rat - Fukomys darlingi; naked mole-rat - Heterocephalus glaber) and found unexceptional otoacoustic emission values. Measurements were complicated by the remarkably long, narrow and curved external ear canals of these animals, for which we provide a morphological description. Both DPOAE and SFOAE displayed the highest amplitudes near 1 kHz, which corresponds to the region of best hearing in all tested species, as well as to the frequency region of the low-frequency acoustic fovea previously described in Ansell's mole-rat. Thus, the cochlea in African mole-rats shares the ability to generate evoked otoacoustic emission with other mammals.
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Affiliation(s)
- Geoffrey A Manley
- Department of Neuroscience, Faculty of Medicine, and Cluster of Excellence "Hearing for All", University of Oldenburg, 26129 Oldenburg, Germany.
| | - Bert Maat
- University of Groningen, University Medical Center Groningen, Department of Otorhinolaryngology/Head and Neck Surgery, Groningen, The Netherlands
| | - Sabine Begall
- Department of General Zoology, University of Duisburg-Essen, Essen, Germany
| | - Pascal Malkemper
- Max Planck Research Group Neurobiology of Magnetoreception, Max Planck Institute for Neurobiology of Behavior - caesar, Bonn, Germany
| | - Kai R Caspar
- Department of General Zoology, University of Duisburg-Essen, Essen, Germany; Institute for Cell Biology, Heinrich Heine University, Düsseldorf, Germany
| | - Leif Moritz
- Max Planck Research Group Neurobiology of Magnetoreception, Max Planck Institute for Neurobiology of Behavior - caesar, Bonn, Germany
| | - Pim van Dijk
- University of Groningen, University Medical Center Groningen, Department of Otorhinolaryngology/Head and Neck Surgery, Groningen, The Netherlands
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3
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Williams IR, Filimontseva A, Connelly CJ, Ryugo DK. The lateral superior olive in the mouse: Two systems of projecting neurons. Front Neural Circuits 2022; 16:1038500. [PMID: 36338332 PMCID: PMC9630946 DOI: 10.3389/fncir.2022.1038500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Accepted: 09/29/2022] [Indexed: 01/24/2023] Open
Abstract
The lateral superior olive (LSO) is a key structure in the central auditory system of mammals that exerts efferent control on cochlear sensitivity and is involved in the processing of binaural level differences for sound localization. Understanding how the LSO contributes to these processes requires knowledge about the resident cells and their connections with other auditory structures. We used standard histological stains and retrograde tracer injections into the inferior colliculus (IC) and cochlea in order to characterize two basic groups of neurons: (1) Principal and periolivary (PO) neurons have projections to the IC as part of the ascending auditory pathway; and (2) lateral olivocochlear (LOC) intrinsic and shell efferents have descending projections to the cochlea. Principal and intrinsic neurons are intermixed within the LSO, exhibit fusiform somata, and have disk-shaped dendritic arborizations. The principal neurons have bilateral, symmetric, and tonotopic projections to the IC. The intrinsic efferents have strictly ipsilateral projections, known to be tonotopic from previous publications. PO and shell neurons represent much smaller populations (<10% of principal and intrinsic neurons, respectively), have multipolar somata, reside outside the LSO, and have non-topographic, bilateral projections. PO and shell neurons appear to have widespread projections to their targets that imply a more diffuse modulatory function. The somata and dendrites of principal and intrinsic neurons form a laminar matrix within the LSO and share quantifiably similar alignment to the tonotopic axis. Their restricted projections emphasize the importance of frequency in binaural processing and efferent control for auditory perception. This study addressed and expanded on previous findings of cell types, circuit laterality, and projection tonotopy in the LSO of the mouse.
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Affiliation(s)
- Isabella R. Williams
- Garvan Institute of Medical Research, Darlinghurst, NSW, Australia,School of Medical Sciences, University of New South Wales, Kensington, NSW, Australia,*Correspondence: Isabella R. Williams,
| | | | - Catherine J. Connelly
- Garvan Institute of Medical Research, Darlinghurst, NSW, Australia,School of Medical Sciences, University of New South Wales, Kensington, NSW, Australia
| | - David K. Ryugo
- Garvan Institute of Medical Research, Darlinghurst, NSW, Australia,School of Medical Sciences, University of New South Wales, Kensington, NSW, Australia,Department of Otolaryngology-Head, Neck and Skull Base Surgery, St. Vincent’s Hospital, Darlinghurst, NSW, Australia
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4
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Ragland NH, Compo NR, Wiltshire N, Shepard A, Troutman S, Kissil JL, Engelman RW. Housing and Husbandry Alternatives for Naked Mole Rat Colonies Used in Research Settings. JOURNAL OF THE AMERICAN ASSOCIATION FOR LABORATORY ANIMAL SCIENCE : JAALAS 2022; 61:412-418. [PMID: 35944976 PMCID: PMC9536831 DOI: 10.30802/aalas-jaalas-22-000035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Naked mole rats (Heterocephalus glaber) are a unique rodent species originating in Africa and are increasingly being used in research. Their needs and characteristics differ from those of other rodents used in research. Unique housing systems are necessary to address the special macro- and microenvironmental requirements of NMRs. Naked mole rats are one of the 2 known eusocial mammalian species, are extremely long-living, are active burrowers, and are accustomed to a subterranean environment. Unlike typical rats and mice, naked mole rats need specific, unique housing systems that mimic their natural subterranean environment to support health and longevity. Here we provide an overview of naked mole rats and a housing method that can be used in research settings.
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Affiliation(s)
- Natalie H Ragland
- Department of Biomedical Sciences, Ross University School of Veterinary Medicine, Basseterre, Saint Kitts and Nevis,Corresponding author.
| | - Nicole R Compo
- Department of Comparative Medicine, University of South Florida, Tampa, Florida,,H. Lee Moffitt Cancer Center & Research Institute, Tampa, Florida
| | - Norman Wiltshire
- Department of Comparative Medicine, University of South Florida, Tampa, Florida,,H. Lee Moffitt Cancer Center & Research Institute, Tampa, Florida
| | - Alyssa Shepard
- H. Lee Moffitt Cancer Center & Research Institute, Tampa, Florida
| | - Scott Troutman
- H. Lee Moffitt Cancer Center & Research Institute, Tampa, Florida
| | - Joseph L Kissil
- H. Lee Moffitt Cancer Center & Research Institute, Tampa, Florida
| | - Robert W Engelman
- Department of Comparative Medicine, University of South Florida, Tampa, Florida,,H. Lee Moffitt Cancer Center & Research Institute, Tampa, Florida
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5
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McCullagh EA, Peacock J, Lucas A, Poleg S, Greene NT, Gaut A, Lagestee S, Zhang Y, Kaczmarek LK, Park TJ, Tollin DJ, Klug A. Auditory brainstem development of naked mole-rats ( Heterocephalus glaber). Proc Biol Sci 2022; 289:20220878. [PMID: 35946148 PMCID: PMC9363996 DOI: 10.1098/rspb.2022.0878] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Life underground often leads to animals having specialized auditory systems to accommodate the constraints of acoustic transmission in tunnels. Despite living underground, naked mole-rats use a highly vocal communication system, implying that they rely on central auditory processing. However, little is known about these animals' central auditory system, and whether it follows a similar developmental time course as other rodents. Naked mole-rats show slowed development in the hippocampus suggesting they have altered brain development compared to other rodents. Here, we measured morphological characteristics and voltage-gated potassium channel Kv3.3 expression and protein levels at different key developmental time points (postnatal days 9, 14, 21 and adulthood) to determine whether the auditory brainstem (lateral superior olive and medial nucleus of the trapezoid body) develops similarly to two common auditory rodent model species: gerbils and mice. Additionally, we measured the hearing onset of naked mole-rats using auditory brainstem response recordings at the same developmental timepoints. In contrast with other work in naked mole-rats showing that they are highly divergent in many aspects of their physiology, we show that naked mole-rats have a similar hearing onset, between postnatal day (P) 9 and P14, to many other rodents. On the other hand, we show some developmental differences, such as a unique morphology and Kv3.3 protein levels in the brainstem.
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Affiliation(s)
| | - John Peacock
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Alexandra Lucas
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Shani Poleg
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Nathaniel T. Greene
- Department of Otolaryngology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Addison Gaut
- Department of Integrative Biology, Oklahoma State University, Stillwater, OK, USA
| | - Samantha Lagestee
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL USA
| | - Yalan Zhang
- Department of Pharmacology, Yale University, New Haven, CT, USA
| | - Leonard K. Kaczmarek
- Department of Pharmacology, Yale University, New Haven, CT, USA
- Department of Cellular and Molecular Physiology, Yale University, New Haven, CT, USA
| | - Thomas J. Park
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL USA
| | - Daniel J. Tollin
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
- Department of Otolaryngology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Achim Klug
- Department of Physiology and Biophysics, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
- Department of Otolaryngology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
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6
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Dymskaya MM, Volodin IA, Smorkatcheva AV, Vasilieva NA, Volodina EV. Audible, but not ultrasonic, calls reflect surface-dwelling or subterranean specialization in pup and adult Brandt’s and mandarin voles. Behav Ecol Sociobiol 2022. [DOI: 10.1007/s00265-022-03213-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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7
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Hite NJ, Sudheimer KD, Anderson L, Sarko DK. Spatial Learning and Memory in the Naked Mole-Rat: Evolutionary Adaptations to a Subterranean Niche. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.879989] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Evolutionary adaptation to a subterranean habitat consisting of extensive underground tunnel systems would presumably require adept spatial learning and memory, however, such capabilities have not been characterized to date in naked mole-rats (Heterocephalus glaber) which, like other members of Bathyergidae, are subterranean rodents. The goal of this study was to develop a method for effectively assessing spatial learning and memory by modifying a Hebb-Williams maze for use with these subterranean rodents. Established behavioral tests to assess spatial learning and memory have primarily focused on, and have been optimized for, more typical laboratory rodent species such as mice and rats. In the current study, we utilized species-appropriate motivators, analyzed learning curves associated with maze performance, and tested memory retention in naked mole-rats. Using a modified Hebb-Williams maze, naked mole-rats underwent 3 days of training, consisting of five trials per day wherein they could freely explore the maze in search of the reward chamber. Memory retention was then tested 1 day, 1 week, and 1 month following the last day of training. Performance was analyzed based on latency to the reward chamber, errors made, and distance traveled to reach the reward chamber. Overall, this study established a behavioral paradigm for assessing maze navigation, spatial learning, and spatial memory in subterranean rodents, including optimization of rewards and environmental motivators.
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8
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Wong HS, Freeman DA, Zhang Y. Not just a cousin of the naked mole-rat: Damaraland mole-rats offer unique insights into biomedicine. Comp Biochem Physiol B Biochem Mol Biol 2022; 262:110772. [PMID: 35710053 PMCID: PMC10155858 DOI: 10.1016/j.cbpb.2022.110772] [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: 03/31/2022] [Revised: 06/07/2022] [Accepted: 06/09/2022] [Indexed: 11/26/2022]
Abstract
Evolutionary medicine has been a fast-growing field of biological research in the past decade. One of the strengths of evolutionary medicine is to use non-traditional model organisms which often exhibit unusual characteristics shaped by natural selection. Studying these unusual traits could provide valuable insight to understand biomedical questions, since natural selection likely discovers solutions to those complex biological problems. Because of many unusual traits, the naked mole-rat (NMR) has attracted attention from different research areas such as aging, cancer, and hypoxia- and hypercapnia-related disorders. However, such uniqueness of NMR physiology may sometimes make the translational study to human research difficult. Damaraland mole-rat (DMR) shares multiple characteristics in common with NMR, but shows higher degree of similarity with human in some aspects of their physiology. Research on DMR could therefore offer alternative insights and might bridge the gap between experimental findings from NMR to human biomedical research. In this review, we discuss studies of DMR as an extension of the current set of model organisms to help better understand different aspects of human biology and disease. We hope to encourage researchers to consider studying DMR together with NMR. By studying these two similar but evolutionarily distinct species, we can harvest the power of convergent evolution and avoid the potential biased conclusions based on life-history of a single species.
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Affiliation(s)
- Hoi-Shan Wong
- Nine Square Therapeutics, South San Francisco, CA 94080, United States of America.
| | - David A Freeman
- Department of Biological Sciences, The University of Memphis, Memphis, TN 38152, United States of America
| | - Yufeng Zhang
- College of Health Sciences, The University of Memphis, Memphis, TN 38152, United States of America.
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9
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Buffenstein R, Amoroso V, Andziak B, Avdieiev S, Azpurua J, Barker AJ, Bennett NC, Brieño‐Enríquez MA, Bronner GN, Coen C, Delaney MA, Dengler‐Crish CM, Edrey YH, Faulkes CG, Frankel D, Friedlander G, Gibney PA, Gorbunova V, Hine C, Holmes MM, Jarvis JUM, Kawamura Y, Kutsukake N, Kenyon C, Khaled WT, Kikusui T, Kissil J, Lagestee S, Larson J, Lauer A, Lavrenchenko LA, Lee A, Levitt JB, Lewin GR, Lewis Hardell KN, Lin TD, Mason MJ, McCloskey D, McMahon M, Miura K, Mogi K, Narayan V, O'Connor TP, Okanoya K, O'Riain MJ, Park TJ, Place NJ, Podshivalova K, Pamenter ME, Pyott SJ, Reznick J, Ruby JG, Salmon AB, Santos‐Sacchi J, Sarko DK, Seluanov A, Shepard A, Smith M, Storey KB, Tian X, Vice EN, Viltard M, Watarai A, Wywial E, Yamakawa M, Zemlemerova ED, Zions M, Smith ESJ. The naked truth: a comprehensive clarification and classification of current 'myths' in naked mole-rat biology. Biol Rev Camb Philos Soc 2022; 97:115-140. [PMID: 34476892 PMCID: PMC9277573 DOI: 10.1111/brv.12791] [Citation(s) in RCA: 52] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 08/17/2021] [Accepted: 08/18/2021] [Indexed: 12/17/2022]
Abstract
The naked mole-rat (Heterocephalus glaber) has fascinated zoologists for at least half a century. It has also generated considerable biomedical interest not only because of its extraordinary longevity, but also because of unusual protective features (e.g. its tolerance of variable oxygen availability), which may be pertinent to several human disease states, including ischemia/reperfusion injury and neurodegeneration. A recent article entitled 'Surprisingly long survival of premature conclusions about naked mole-rat biology' described 28 'myths' which, those authors claimed, are a 'perpetuation of beautiful, but falsified, hypotheses' and impede our understanding of this enigmatic mammal. Here, we re-examine each of these 'myths' based on evidence published in the scientific literature. Following Braude et al., we argue that these 'myths' fall into four main categories: (i) 'myths' that would be better described as oversimplifications, some of which persist solely in the popular press; (ii) 'myths' that are based on incomplete understanding, where more evidence is clearly needed; (iii) 'myths' where the accumulation of evidence over the years has led to a revision in interpretation, but where there is no significant disagreement among scientists currently working in the field; (iv) 'myths' where there is a genuine difference in opinion among active researchers, based on alternative interpretations of the available evidence. The term 'myth' is particularly inappropriate when applied to competing, evidence-based hypotheses, which form part of the normal evolution of scientific knowledge. Here, we provide a comprehensive critical review of naked mole-rat biology and attempt to clarify some of these misconceptions.
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Affiliation(s)
| | - Vincent Amoroso
- Department of Biological SciencesUniversity of Illinois at ChicagoChicagoIL60607U.S.A.
| | - Blazej Andziak
- Graduate Center City University of New York365 Fifth AvenueNew YorkNY10016U.S.A.
| | | | - Jorge Azpurua
- Department of AnesthesiologyStony Brook University101 Nicolls RoadStony BrookNY11794U.S.A.
| | - Alison J. Barker
- Max Delbrück Center for Molecular MedicineRobert‐Rössle‐Str 10Berlin‐Buch13092Germany
| | - Nigel C. Bennett
- Mammal Research Institute, Department of Zoology and EntomologyUniversity of PretoriaPretoria0002South Africa
| | - Miguel A. Brieño‐Enríquez
- Department of Obstetrics, Gynecology & Reproductive MedicineMagee‐Womens Research Institute204 Craft AvenuePittsburghPA15213U.S.A.
| | - Gary N. Bronner
- Department Biological SciencesRondeboschCape Town7701South Africa
| | - Clive Coen
- Reproductive Neurobiology, Division of Women's HealthSchool of Medicine, King's College LondonWestminster Bridge RoadLondonSE1 7EHU.K.
| | - Martha A. Delaney
- Zoological Pathology ProgramUniversity of Illinois3505 Veterinary Medicine Basic Sciences Building, 2001 S Lincoln AvenueUrbanaIL6180U.S.A.
| | - Christine M. Dengler‐Crish
- Department of Pharmaceutical SciencesNortheast Ohio Medical University4209 State Route 44RootstownOH44272U.S.A.
| | - Yael H. Edrey
- Northwest Vista College3535 N. Ellison DriveSan AntonioTX78251U.S.A.
| | - Chris G. Faulkes
- School of Biological and Chemical SciencesQueen Mary University of LondonMile End RoadLondonE1 4NSU.K.
| | - Daniel Frankel
- School of EngineeringNewcastle UniversityMerz CourtNewcastle Upon TyneNE1 7RUU.K.
| | - Gerard Friedlander
- Université Paris DescartesFaculté de Médecine12 Rue de l'École de MédecineParis5006France
| | - Patrick A. Gibney
- Cornell University College of Veterinary MedicineIthacaNY14853U.S.A.
| | - Vera Gorbunova
- Departments of BiologyUniversity of Rochester402 Hutchison HallRochesterNY14627U.S.A.
| | - Christopher Hine
- Cleveland ClinicLerner Research Institute9500 Euclid AvenueClevelandOH44195U.S.A.
| | - Melissa M. Holmes
- Department of PsychologyUniversity of Toronto Mississauga3359 Mississauga Road NorthMississaugaONL5L 1C6Canada
| | | | - Yoshimi Kawamura
- Department of Aging and Longevity ResearchKumamoto University1‐1‐1 HonjoKumamoto860‐0811Japan
| | - Nobuyuki Kutsukake
- Department of Evolutionary Studies of BiosystemsThe Graduate University for Advanced StudiesHayama240‐0193Japan
| | - Cynthia Kenyon
- Calico Life Sciences LLC1170 Veterans BlvdSouth San FranciscoCA94080U.S.A.
| | - Walid T. Khaled
- The School of the Biological SciencesUniversity of CambridgeTennis Court RoadCambridgeCB2 1PDU.K.
| | - Takefumi Kikusui
- Companion Animal Research, School of Veterinary MedicineAzabu UniversitySagamihara252‐5201Japan
| | - Joseph Kissil
- Department of Cancer BiologyThe Scripps Research InstituteScripps FloridaJupiterFL33458U.S.A.
| | - Samantha Lagestee
- Department of Biological SciencesUniversity of Illinois at ChicagoChicagoIL60607U.S.A.
| | - John Larson
- Department of Biological SciencesUniversity of Illinois at ChicagoChicagoIL60607U.S.A.
| | - Amanda Lauer
- Department of OtolaryngologyJohns Hopkins School of MedicineBaltimoreMD21205U.S.A.
| | - Leonid A. Lavrenchenko
- A.N. Severtsov Institute of Ecology and EvolutionRussian Academy of SciencesLeninskii pr. 33Moscow119071Russia
| | - Angela Lee
- Graduate Center City University of New York365 Fifth AvenueNew YorkNY10016U.S.A.
| | - Jonathan B. Levitt
- Biology DepartmentThe City College of New York138th Street and Convent AvenueNew YorkNY10031U.S.A.
| | - Gary R. Lewin
- Max Delbrück Center for Molecular MedicineRobert‐Rössle‐Str 10Berlin‐Buch13092Germany
| | | | - TzuHua D. Lin
- Calico Life Sciences LLC1170 Veterans BlvdSouth San FranciscoCA94080U.S.A.
| | - Matthew J. Mason
- The School of the Biological SciencesUniversity of CambridgeTennis Court RoadCambridgeCB2 1PDU.K.
| | - Dan McCloskey
- College of Staten Island in the City University of New York2800 Victory BlvdStaten IslandNY10314U.S.A.
| | - Mary McMahon
- Calico Life Sciences LLC1170 Veterans BlvdSouth San FranciscoCA94080U.S.A.
| | - Kyoko Miura
- Department of Aging and Longevity ResearchKumamoto University1‐1‐1 HonjoKumamoto860‐0811Japan
| | - Kazutaka Mogi
- Companion Animal Research, School of Veterinary MedicineAzabu UniversitySagamihara252‐5201Japan
| | - Vikram Narayan
- Calico Life Sciences LLC1170 Veterans BlvdSouth San FranciscoCA94080U.S.A.
| | | | - Kazuo Okanoya
- Department of Life SciencesThe University of Tokyo7‐3‐1 HongoTokyo153‐8902Japan
| | | | - Thomas J. Park
- Department of Biological SciencesUniversity of Illinois at ChicagoChicagoIL60607U.S.A.
| | - Ned J. Place
- Cornell University College of Veterinary MedicineIthacaNY14853U.S.A.
| | - Katie Podshivalova
- Calico Life Sciences LLC1170 Veterans BlvdSouth San FranciscoCA94080U.S.A.
| | | | - Sonja J. Pyott
- Groningen Department of OtorhinolaryngologyUniversity Medical CenterPostbus 30.001GroningenRB9700The Netherlands
| | - Jane Reznick
- Cologne Excellence Cluster for Cellular Stress Responses in Aging‐Associated Diseases (CECAD)University Hospital CologneJoseph‐Stelzmann‐Street 26Cologne50931Germany
| | - J. Graham Ruby
- Calico Life Sciences LLC1170 Veterans BlvdSouth San FranciscoCA94080U.S.A.
| | - Adam B. Salmon
- Barshop Institute for Longevity and Aging StudiesUniversity of Texas Health Science Center4939 Charles Katz Dr.San AntonioTX78229U.S.A.
| | - Joseph Santos‐Sacchi
- Department of NeuroscienceYale University School of Medicine200 South Frontage Road, SHM C‐303New HavenCT06510U.S.A.
| | - Diana K. Sarko
- Department of AnatomySchool of Medicine, Southern Illinois University975 S. NormalCarbondaleIL62901U.S.A.
| | - Andrei Seluanov
- Departments of BiologyUniversity of Rochester402 Hutchison HallRochesterNY14627U.S.A.
| | - Alyssa Shepard
- Department of Cancer BiologyThe Scripps Research InstituteScripps FloridaJupiterFL33458U.S.A.
| | - Megan Smith
- Calico Life Sciences LLC1170 Veterans BlvdSouth San FranciscoCA94080U.S.A.
| | - Kenneth B. Storey
- Department of BiologyCarleton University1125 Colonel By DriveOttawaONK1S 5B6Canada
| | - Xiao Tian
- Department of Genetics – Blavatnik InstituteHarvard Medical School77 Avenue Louis PasteurBostonMA02115U.S.A.
| | - Emily N. Vice
- Department of Biological SciencesUniversity of Illinois at ChicagoChicagoIL60607U.S.A.
| | - Mélanie Viltard
- Fondation pour la recherche en PhysiologieUniversité Catholique de LouvainClos Chapelle‐aux‐Champs 30Woluwe‐saint Lambert1200Belgium
| | - Akiyuki Watarai
- Companion Animal Research, School of Veterinary MedicineAzabu UniversitySagamihara252‐5201Japan
| | - Ewa Wywial
- Biology DepartmentThe City College of New York138th Street and Convent AvenueNew YorkNY10031U.S.A.
| | - Masanori Yamakawa
- Department of Evolutionary Studies of BiosystemsThe Graduate University for Advanced StudiesHayama240‐0193Japan
| | - Elena D. Zemlemerova
- A.N. Severtsov Institute of Ecology and EvolutionRussian Academy of SciencesLeninskii pr. 33Moscow119071Russia
| | - Michael Zions
- Graduate Center City University of New York365 Fifth AvenueNew YorkNY10016U.S.A.
| | - Ewan St. John Smith
- The School of the Biological SciencesUniversity of CambridgeTennis Court RoadCambridgeCB2 1PDU.K.
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10
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Caspar KR, Heinrich A, Mellinghaus L, Gerhardt P, Begall S. Evoked auditory potentials from African mole-rats and coruros reveal disparity in subterranean rodent hearing. J Exp Biol 2021; 224:272630. [PMID: 34704596 DOI: 10.1242/jeb.243371] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 10/22/2021] [Indexed: 12/28/2022]
Abstract
Hearing in subterranean rodents exhibits numerous peculiarities, including low sensitivity and restriction to a narrow range of comparatively low frequencies. Past studies provided two conflicting hypotheses explaining how these derived traits evolved: structural degeneration and adaptive specialization. To further elucidate this issue, we recorded auditory brainstem responses from three species of social subterranean rodents that differ in the degree of specialization to the underground habitat: the naked mole-rat (Heterocephalus glaber) and the Mashona mole-rat (Fukomys darlingi), which represent the ancient lineage of African mole-rats (Bathyergidae), and the coruro (Spalacopus cyanus), a South American rodent (Octodontidae) that adopted a subterranean lifestyle in more recent geological time. Additionally, we measured call amplitudes of social vocalizations to study auditory vocal coupling. We found elevated auditory thresholds and severe hearing range restrictions in the African mole-rats, with hearing in naked mole-rats tending to be more sensitive than in Mashona mole-rats, in which hearing notably deteriorated with increasing age. In contrast, hearing in coruros was similar to that of epigeic rodents, with its range extending into ultrasonic frequencies. However, as in the mole-rats, the coruros' region of best hearing was located at low frequencies close to 1 kHz. We argue that the auditory sensitivity of African mole-rats, although remarkably poor, has been underestimated by recent studies, whereas data on coruros conform to previous results. Considering the available evidence, we propose to be open to both degenerative and adaptive interpretations of hearing physiology in subterranean mammals, as each may provide convincing explanations for specific auditory traits observed.
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Affiliation(s)
- Kai R Caspar
- Department of General Zoology, University of Duisburg-Essen, Universitaetsstraße 5, 45141 Essen, Germany
| | - Alexandra Heinrich
- Department of General Zoology, University of Duisburg-Essen, Universitaetsstraße 5, 45141 Essen, Germany
| | - Lea Mellinghaus
- Department of General Zoology, University of Duisburg-Essen, Universitaetsstraße 5, 45141 Essen, Germany
| | - Patricia Gerhardt
- Institute of Physiology, Faculty of Medicine, University of Duisburg-Essen, 45147 Essen, Germany
| | - Sabine Begall
- Department of General Zoology, University of Duisburg-Essen, Universitaetsstraße 5, 45141 Essen, Germany
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11
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Vice EN, Lagestee S, Browe BM, Deb D, Smith ESJ, Park TJ. Sensory Systems of the African Naked Mole-Rat. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1319:137-156. [PMID: 34424515 DOI: 10.1007/978-3-030-65943-1_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Naked mole-rats share some sensory characteristics with other subterraneans, including lack of object vision, retention of the ability to entrain their circadian rhythm to light, and poor hearing. On the other hand, a characteristic that may be specialized in the naked mole-rat is their exquisite orienting responses to the touch of even a single body vibrissa. They have about 100 whisker-like body vibrissae on their otherwise furless bodies. They are also insensitive to chemical and inflammatory pain, likely an adaptation to living in an atmosphere that is high in carbon dioxide, a result of many respiring individuals driving carbon dioxide accumulation. Naked mole-rats have the highest population density among subterranean mammals. High levels of carbon dioxide cause tissue acidosis and associated pain. Remarkably, naked mole-rats are completely immune to carbon dioxide-induced pulmonary edema. However, they retain the ability to detect acid as a taste (sour). Finally, their ability to smell and discriminate odors is comparable to that of rats and mice, but their vomeronasal organ, associated with sensing pheromones, is extremely small and shows a complete lack of post-natal growth. In this chapter, we review what is known about the sensory systems of the naked mole-rat with emphasis on how they differ from other mammals, and even other subterraneans. More extensive accounts of the naked mole-rat's auditory and pain systems can be found in other chapters of this book.
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Affiliation(s)
- Emily N Vice
- Laboratory of Integrative Neuroscience, Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL, USA
| | - Samantha Lagestee
- Laboratory of Integrative Neuroscience, Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL, USA
| | - Brigitte M Browe
- Laboratory of Integrative Neuroscience, Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL, USA
| | - Deblina Deb
- Laboratory of Integrative Neuroscience, Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL, USA.,Kids In Motion Pediatric Therapy Services, Highland, MI, USA
| | - Ewan St J Smith
- Department of Pharmacology, University of Cambridge, Cambridge, UK
| | - Thomas J Park
- Laboratory of Integrative Neuroscience, Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL, USA.
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12
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Affiliation(s)
- Rochelle Buffenstein
- Calico Life Sciences LLC, 1170 Veterans Boulevard, South San Francisco, CA 94080, USA.
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13
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Delaney MA, Imai DM, Buffenstein R. Spontaneous Disease and Pathology of Naked Mole-Rats. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1319:353-380. [PMID: 34424525 DOI: 10.1007/978-3-030-65943-1_15] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Naked mole-rats are highly valuable research models and popular exhibition animals at zoos worldwide. Here, we provide comprehensive descriptions of common postmortem findings of naked mole-rats from both research colonies and populations managed in zoological institutions. Included are brief reviews of their natural history and related physiologic adaptations, unique anatomical features, gross and histologic lesions of common as well as rarely reported disease processes, and discussions of possible pathogeneses with recommendations for future investigations to fill knowledge gaps. Based on postmortem data of several hundreds of naked mole-rats in managed care, it is clear that cancer is extremely rare and infectious disease is infrequently reported. However, despite relatively benign aging phenotypes in this species, several degenerative processes have been nevertheless observed in older populations of naked mole-rats. As such, some potential diet and husbandry-related issues are discussed in addition to the one of the most prominent causes of morbidity and mortality, conspecific aggression and traumas. From this review of lesions and disease, it is clear that pathology, including histopathology, is integral to better understanding mechanisms of healthy aging and cancer resistance of these extraordinary rodents.
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Affiliation(s)
- Martha A Delaney
- Zoological Pathology Program, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
| | - Denise M Imai
- Comparative Pathology Laboratory, School of Veterinary Medicine, University of California at Davis, Davis, CA, USA
| | - Rochelle Buffenstein
- Calico Life Sciences LLC, South San Francisco, CA, USA. .,Department of Pharmacology, University of Texas Health at San Antonio, San Antonio, TX, USA.
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14
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Barker AJ, Koch U, Lewin GR, Pyott SJ. Hearing and Vocalizations in the Naked Mole-Rat. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1319:157-195. [PMID: 34424516 DOI: 10.1007/978-3-030-65943-1_6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Since their discovery, naked mole-rats have been speaking to us. Early field studies noted their extensive vocalizations, and scientists who are fortunate enough to spend time with these creatures in the laboratory setting cannot help but notice their constant peeping, chirruping and grunting (Hill et al., Proc Zool Soc Lond 128:455-514, 1957). Yet, few dwell on the function of these chirps and peeps, being instead drawn to the many other extraordinary aspects of naked mole-rat physiology detailed throughout this book. Still, no biology is complete without a description of how an organism communicates. While the field of naked mole-rat bioacoustics and acoustic communication has been largely silent for many years, we highlight recent progress in understanding how and what Heterocephalus glaber hears and which vocalizations it uses. These efforts are essential for a complete understanding of naked mole-rat cooperation, society and even culture.
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Affiliation(s)
- Alison J Barker
- Max Planck Institute for Brain Research, Max-von-Laue-Straße 4, Frankfurt am Main, Germany
| | - Ursula Koch
- Institute of Biology, Freie Universität Berlin, Berlin, Germany
| | - Gary R Lewin
- Molecular Physiology of Somatic Sensation, Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Sonja J Pyott
- Department of Otorhinolaryngology and Head/Neck Surgery, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
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15
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Pyott SJ, van Tuinen M, Screven LA, Schrode KM, Bai JP, Barone CM, Price SD, Lysakowski A, Sanderford M, Kumar S, Santos-Sacchi J, Lauer AM, Park TJ. Functional, Morphological, and Evolutionary Characterization of Hearing in Subterranean, Eusocial African Mole-Rats. Curr Biol 2020; 30:4329-4341.e4. [PMID: 32888484 DOI: 10.1016/j.cub.2020.08.035] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 06/09/2020] [Accepted: 08/07/2020] [Indexed: 12/26/2022]
Abstract
Naked mole-rats are highly vocal, eusocial, subterranean rodents with, counterintuitively, poor hearing. The causes underlying their altered hearing are unknown. Moreover, whether altered hearing is degenerate or adaptive to their unique lifestyles is controversial. We used various methods to identify the factors contributing to altered hearing in naked and the related Damaraland mole-rats and to examine whether these alterations result from relaxed or adaptive selection. Remarkably, we found that cochlear amplification was absent from both species despite normal prestin function in outer hair cells isolated from naked mole-rats. Instead, loss of cochlear amplification appears to result from abnormal hair bundle morphologies observed in both species. By exploiting a well-curated deafness phenotype-genotype database, we identified amino acid substitutions consistent with abnormal hair bundle morphology and reduced hearing sensitivity. Amino acid substitutions were found in unique groups of six hair bundle link proteins. Molecular evolutionary analyses revealed shifts in selection pressure at both the gene and the codon level for five of these six hair bundle link proteins. Substitutions in three of these proteins are associated exclusively with altered hearing. Altogether, our findings identify the likely mechanism of altered hearing in African mole-rats, making them the only identified mammals naturally lacking cochlear amplification. Moreover, our findings suggest that altered hearing in African mole-rats is adaptive, perhaps tailoring hearing to eusocial and subterranean lifestyles. Finally, our work reveals multiple, unique evolutionary trajectories in African mole-rat hearing and establishes species members as naturally occurring disease models to investigate human hearing loss.
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Affiliation(s)
- Sonja J Pyott
- University Medical Center Groningen and University of Groningen, Department of Otorhinolaryngology and Head/Neck Surgery, 9713GZ Groningen, the Netherlands.
| | - Marcel van Tuinen
- University Medical Center Groningen and University of Groningen, Department of Otorhinolaryngology and Head/Neck Surgery, 9713GZ Groningen, the Netherlands
| | - Laurel A Screven
- Johns Hopkins School of Medicine, Department of Otolaryngology, Baltimore, MD 21205, USA
| | - Katrina M Schrode
- Johns Hopkins School of Medicine, Department of Otolaryngology, Baltimore, MD 21205, USA
| | - Jun-Ping Bai
- Yale University School of Medicine, Department of Neurology, 333 Cedar Street, New Haven, CT 06510, USA
| | - Catherine M Barone
- University of Illinois at Chicago, Department of Biological Sciences, Chicago, IL 60612, USA
| | - Steven D Price
- University of Illinois at Chicago, Department of Anatomy and Cell Biology, Chicago, IL 60612, USA
| | - Anna Lysakowski
- University of Illinois at Chicago, Department of Anatomy and Cell Biology, Chicago, IL 60612, USA
| | - Maxwell Sanderford
- Temple University, Institute for Genomics and Evolutionary Medicine and Department of Biology, Philadelphia, PA 19122, USA
| | - Sudhir Kumar
- Temple University, Institute for Genomics and Evolutionary Medicine and Department of Biology, Philadelphia, PA 19122, USA; King Abdulaziz University, Center for Excellence in Genome Medicine and Research, Jeddah, Saudi Arabia
| | - Joseph Santos-Sacchi
- Yale University School of Medicine, Department of Surgery (Otolaryngology) and Department of Neuroscience and Cellular and Molecular Physiology, 333 Cedar Street, New Haven, CT 06510, USA
| | - Amanda M Lauer
- Johns Hopkins School of Medicine, Department of Otolaryngology, Baltimore, MD 21205, USA
| | - Thomas J Park
- University of Illinois at Chicago, Department of Biological Sciences, Chicago, IL 60612, USA
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16
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Li H, Lv J, Zhou Q, Jin L, Kang Z, Huang Y. Establishment of sperm associated antigen 6 gene knockout mouse model and its mechanism of deafness. Saudi J Biol Sci 2020; 27:1289-1295. [PMID: 32346337 PMCID: PMC7182980 DOI: 10.1016/j.sjbs.2020.03.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 02/28/2020] [Accepted: 03/08/2020] [Indexed: 11/01/2022] Open
Abstract
To investigate the effects of knocking out the Sperm associated antigen6 (Spag6) gene on the auditory system of mice, the heterozygous type Spag6 knockout mouse model built in the previous period was used for mating and breeding, and homozygous type Spag6 gene knockout mouse (Spag-/-), heterozygous type Spag6 gene knockout mouse (Spag+/-) and wild type mouse (Spag+/+) were obtained. PCR technology was used to verify mouse models with different genotypes. After verification, the hearing threshold responses of Spag+/+ and Spag-/- genotype mice were detected. The localization of Spag6 gene in the basal membrane of the cochlea of the inner ear was detected by immunofluorescence staining. The changes of middle ear tissues were observed by H.E. staining sections. The relative expression of Prestin gene and Pgrn gene in different age mice was detected by fluorescence quantitative PCR. The relative expression of Prestin gene was detected by western blot. The results showed that Spag-/- mice had hearing impairment compared with Spag+/+ mice. And Spag6 protein is distributed in different genotypes of mouse hair cells; Spag-/- mice showed otitis media. The expression of Prestin mRNA and protein in Spag-/- mice was significantly higher than that in Spag+/+ mice (P < 0.01). The expression of Pgrn gene in Spag+/+ mice was significantly higher than that in Spag-/- mice (P < 0.05). It indicates that the loss of Spag6 gene would lead to the decline of hearing sense in mice. It is likely that the Spag6 gene could affect hearing by regulating the expression of Prestin gene. And the absence of the Spag6 gene causes otitis media in mice. The results of this study can lay a theoretical foundation for the follow-up studies of Spag6 gene in deafness diseases.
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Affiliation(s)
- He Li
- Department of Otolaryngology, First Affiliated Hospital of Wenzhou Medical University, Wenzhou city 325000, Zhejiang Province, China
| | - Jun Lv
- Department of Otolaryngology, First Affiliated Hospital of Wenzhou Medical University, Wenzhou city 325000, Zhejiang Province, China
| | - Qinshuang Zhou
- Department of Otolaryngology, First Affiliated Hospital of Wenzhou Medical University, Wenzhou city 325000, Zhejiang Province, China
| | - Lanlan Jin
- Department of Otolaryngology, First Affiliated Hospital of Wenzhou Medical University, Wenzhou city 325000, Zhejiang Province, China
| | - Zonghui Kang
- Department of Otolaryngology, Affiliated Wenzhou Hospital, Zhejiang University of Traditional Chinese Medicine, Wenzhou city 325000, Zhejiang Province, China
| | - Yideng Huang
- Department of Otolaryngology, First Affiliated Hospital of Wenzhou Medical University, Wenzhou city 325000, Zhejiang Province, China
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17
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Cain BW, Reynolds T, Sarko DK. Superficial, suprahyoid, and infrahyoid neck musculature in naked mole-rats (Heterocephalus glaber): Relative size and potential contributions to independent movement of the lower incisors. J Morphol 2019; 280:1185-1196. [PMID: 31180596 DOI: 10.1002/jmor.21022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 05/22/2019] [Accepted: 05/24/2019] [Indexed: 11/06/2022]
Abstract
Naked mole-rats (Heterocephalus glaber) are fossorial, eusocial rodents that exhibit the unusual capability of moving their lower incisors independently in lateral and rostroventral directions. The evolution of this trait would presumably also involve concurrent alterations in neck musculature to support and control movements of the lower incisors. In order to assess morphological adaptations that might facilitate these movements, we performed detailed dissections of the neck musculature of adult naked mole-rats. In addition to characterizing attachment sites of superficial, suprahyoid, and infrahyoid musculature, we also quantified muscle mass and mandibular features thought to be associated with gape (condyle height, condyle length, and jaw length). Based on muscle attachment sites, the platysma myoides may contribute to lateral movement of the lower incisor and hemi-mandible in naked mole-rats. The large digastric muscle is likely to be a main contributor to rostroventral movement of each lower incisor. The geniohyoid and mylohyoid muscles also likely contribute to rostroventral movements of the lower incisors, and the mylohyoid may also produce lateral spreading of the hemi-mandibles. The transverse mandibular (intermandibularis) muscle likely serves to reposition the lower incisors back to a midline orientation following a movement.
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Affiliation(s)
- Blake W Cain
- Southern Illinois University School of Medicine, Department of Anatomy, Carbondale, Illinois
| | - Taylor Reynolds
- Southern Illinois University School of Medicine, Department of Anatomy, Carbondale, Illinois
| | - Diana K Sarko
- Southern Illinois University School of Medicine, Department of Anatomy, Carbondale, Illinois
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18
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Barone CM, Douma S, Reijntjes DOJ, Browe BM, Köppl C, Klump G, Park TJ, Pyott SJ. Altered cochlear innervation in developing and mature naked and Damaraland mole rats. J Comp Neurol 2019; 527:2302-2316. [PMID: 30861124 PMCID: PMC6767702 DOI: 10.1002/cne.24682] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2018] [Revised: 03/06/2019] [Accepted: 03/07/2019] [Indexed: 01/04/2023]
Abstract
Compared to many other rodent species, naked mole rats (Heterocephalus glaber) have elevated auditory thresholds, poor frequency selectivity, and limited ability to localize sound. Because the cochlea is responsible for encoding and relaying auditory signals to the brain, we used immunofluorescence and quantitative image analysis to examine cochlear innervation in mature and developing naked mole rats compared to mice (Mus musculus), gerbils (Meriones unguiculatus), and Damaraland mole rats (Fukomys damarensis), another subterranean rodent. In comparison to mice and gerbils, we observed alterations in afferent and efferent innervation as well as their patterns of developmental refinement in naked and Damaraland mole rats. These alterations were, however, not always shared similarly between naked and Damaraland mole rats. Most conspicuously, in both naked and Damaraland mole rats, inner hair cell (IHC) afferent ribbon density was reduced, whereas outer hair cell afferent ribbon density was increased. Naked and Damaraland mole rats also showed reduced lateral and medial efferent terminal density. Developmentally, naked mole rats showed reduced and prolonged postnatal reorganization of afferent and efferent innervation. Damaraland mole rats showed no evidence of postnatal reorganization. Differences in cochlear innervation specifically between the two subterranean rodents and more broadly among rodents provides insight into the cochlear mechanisms that enhance frequency sensitivity and sound localization, maturation of the auditory system, and the evolutionary adaptations occurring in response to subterranean environments.
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Affiliation(s)
- Catherine M Barone
- Laboratory of Integrative Neuroscience, Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois
| | - Sytse Douma
- Department of Otorhinolaryngology and Head/Neck Surgery, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Daniël O J Reijntjes
- Department of Otorhinolaryngology and Head/Neck Surgery, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Brigitte M Browe
- Laboratory of Integrative Neuroscience, Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois
| | - Christine Köppl
- Cluster of Excellence "Hearing4All", Department of Neuroscience, School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany.,Research Center Neurosensory Science, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
| | - Georg Klump
- Cluster of Excellence "Hearing4All", Department of Neuroscience, School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany.,Research Center Neurosensory Science, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
| | - Thomas J Park
- Laboratory of Integrative Neuroscience, Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois
| | - Sonja J Pyott
- Department of Otorhinolaryngology and Head/Neck Surgery, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
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