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Santana NNM, Silva EHA, Santos SFD, Bezerra LLF, da Silva MMO, Cavalcante JS, Fiuza FP, Morais PLADG, Engelberth RC. Neuronal Stability, Volumetric Changes, and Decrease in GFAP Expression of Marmoset (Callithrix jacchus) Subcortical Visual Nuclei During Aging. J Comp Neurol 2024; 532:e25649. [PMID: 38967410 DOI: 10.1002/cne.25649] [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: 12/14/2023] [Revised: 05/06/2024] [Accepted: 05/30/2024] [Indexed: 07/06/2024]
Abstract
The physiological aging process is well known for functional decline in visual abilities. Among the components of the visual system, the dorsal lateral geniculate nucleus (DLG) and superior colliculus (SC) provide a good model for aging investigations, as these structures constitute the main visual pathways for retinal inputs reaching the visual cortex. However, there are limited data available on quantitative morphological and neurochemical aspects in DLG and SC across lifespan. Here, we used optical density to determine immunoexpression of glial fibrillary acidic protein (GFAP) and design-based stereological probes to estimate the neuronal number, total volume, and layer volume of the DLG and SC in marmosets (Callithrix jacchus), ranging from 36 to 143 months of age. Our results revealed an age-related increase in total volume and layer volume of the DLG, with an overall stability in SC volume. Furthermore, a stable neuronal number was demonstrated in DLG and superficial layers of SC (SCv). A decrease in GFAP immunoexpression was observed in both visual centers. The results indicate region-specific variability in volumetric parameter, possibly attributed to structural plastic events in response to inflammation and compensatory mechanisms at the cellular and subcellular level. Additionally, the DLG and SCv seem to be less vulnerable to aging effects in terms of neuronal number. The neuropeptidergic data suggest that reduced GFAP expression may reflect morphological atrophy in the astroglial cells. This study contributes to updating the current understanding of aging effects in the visual system and stablishes a crucial foundation for future research on visual perception throughout the aging process.
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Affiliation(s)
- Nelyane N M Santana
- Edmond and Lily Safra International Institute of Neuroscience, Santos Dumont Institute, Macaíba, Brazil
| | - Eryck H A Silva
- Laboratory of Neurochemical Studies, Department of Physiology and Behavior, Bioscience Center, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Sâmarah F Dos Santos
- Laboratory of Neurochemical Studies, Department of Physiology and Behavior, Bioscience Center, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Lyzandro L F Bezerra
- Laboratory of Neurochemical Studies, Department of Physiology and Behavior, Bioscience Center, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Maria M O da Silva
- Laboratory of Neurochemical Studies, Department of Physiology and Behavior, Bioscience Center, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Jeferson S Cavalcante
- Laboratory of Neurochemical Studies, Department of Physiology and Behavior, Bioscience Center, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Felipe P Fiuza
- Edmond and Lily Safra International Institute of Neuroscience, Santos Dumont Institute, Macaíba, Brazil
| | - Paulo L A de G Morais
- Laboratory of Experimental Neurology, College of the Health Sciences, University of the State of Rio Grande do Norte, Mossoró, Brazil
| | - Rovena Clara Engelberth
- Laboratory of Neurochemical Studies, Department of Physiology and Behavior, Bioscience Center, Federal University of Rio Grande do Norte, Natal, Brazil
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Onyono PN, Kavoi BM, Kiama SG, Makanya AN. Comparative ultrastructure of the olfactory system in the East African root rat (Tachyoryctes splendens) and the naked mole rat (Heterocephalus glaber). Anat Histol Embryol 2024; 53:e13034. [PMID: 38563613 DOI: 10.1111/ahe.13034] [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: 11/19/2022] [Revised: 12/04/2023] [Accepted: 03/12/2024] [Indexed: 04/04/2024]
Abstract
The ultrastructure of the olfactory system of most fossorial rodents remains largely unexplored. This study sought to investigate the functional structure of the olfactory mucosa and olfactory bulb of two species of fossorial rodents that have distinct behaviour and ecology, the East African root rat (RR) and the naked mole rat (NMR). Transmission electron microscopy and scanning electron microscopy were employed. The basic ultrastructural design of the olfactory system of the two species was largely comparable. In both species, the olfactory mucosa comprised an olfactory epithelium and an underlying lamina propria. The olfactory epithelium revealed olfactory knobs, cilia and microvilli apically and sustentancular cells, olfactory receptor neurons and basal cells in the upper, middle and basal zones, respectively. The lamina propria was constituted by Bowman's glands, olfactory nerve bundles and vasculature supported by loose connective tissue. Within the olfactory bulb, intracellular and extracellular structures including cell organelles, axons and dendrites were elucidated. Notable species differences were observed in the basal zone of the olfactory epithelium and on the luminal surface of the olfactory mucosa. The basal zone of the olfactory epithelium of the RR consisted of a single layer of flattened electron-dense horizontal basal cells while the NMR had juxtaposed electron-dense and electron-lucent heterogenous cells, an occurrence seen as being indicative of quiescent and highly proliferative states of the olfactory epithelia in the two species, respectively. The olfactory epithelial surface of the NMR comprised an elaborate cilia network that intertwined extensively forming loop-like structures whereas in the RR, the surface was rugged and consisted of finger-like processes and irregular masses. With gross and histological studies showing significant differences in the olfactory structures of the two species, these findings are a further manifestation that the olfactory system of the RR and the NMR have evolved differently to reflect their varied olfactory functional needs.
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Affiliation(s)
- P N Onyono
- Department of Veterinary Anatomy and Physiology, Egerton University, Egerton, Kenya
| | - B M Kavoi
- Department of Veterinary Anatomy and Physiology, University of Nairobi, Nairobi, Kenya
| | - S G Kiama
- Department of Veterinary Anatomy and Physiology, University of Nairobi, Nairobi, Kenya
| | - A N Makanya
- Department of Veterinary Anatomy and Physiology, University of Nairobi, Nairobi, Kenya
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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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Oosthuizen MK, Bennett NC. Clocks Ticking in the Dark: A Review of Biological Rhythms in Subterranean African Mole-Rats. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.878533] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Biological rhythms are rhythmic fluctuations of biological functions that occur in almost all organisms and on several time scales. These rhythms are generated endogenously and entail the coordination of physiological and behavioural processes to predictable, external environmental rhythms. The light-dark cycle is usually the most prominent environmental cue to which animals synchronise their rhythms. Biological rhythms are believed to provide an adaptive advantage to organisms. In the present review, we will examine the occurrence of circadian and seasonal rhythms in African mole-rats (family Bathyergidae). African mole-rats are strictly subterranean, they very rarely emerge aboveground and therefore, do not have regular access to environmental light. A key adaptation to their specialised habitat is a reduction in the visual system. Mole-rats exhibit both daily and seasonal rhythmicity in a range of behaviours and physiological variables, albeit to different degrees and with large variability. We review previous research on the entire circadian system of African mole-rats and discuss output rhythms in detail. Laboratory experiments imply that light remains the strongest zeitgeber for entrainment but in the absence of light, animals can entrain to ambient temperature rhythms. Field studies report that rhythmic daily and seasonal behaviour is displayed in their natural habitat. We suggest that ambient temperature and rainfall play an important role in the timing of rhythmic behaviour in mole-rats, and that they likely respond directly to these zeitgebers in the field rather than exhibit robust endogenous rhythms. In the light of climate change, these subterranean animals are buffered from the direct and immediate effects of changes in temperature and rainfall, partly because they do not have robust circadian rhythms, however, on a longer term they are vulnerable to changes in their food sources and dispersal abilities.
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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: 36] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [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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Cooper TK, Meyerholz DK, Beck AP, Delaney MA, Piersigilli A, Southard TL, Brayton CF. Research-Relevant Conditions and Pathology of Laboratory Mice, Rats, Gerbils, Guinea Pigs, Hamsters, Naked Mole Rats, and Rabbits. ILAR J 2022; 62:77-132. [PMID: 34979559 DOI: 10.1093/ilar/ilab022] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 05/12/2021] [Indexed: 12/31/2022] Open
Abstract
Animals are valuable resources in biomedical research in investigations of biological processes, disease pathogenesis, therapeutic interventions, safety, toxicity, and carcinogenicity. Interpretation of data from animals requires knowledge not only of the processes or diseases (pathophysiology) under study but also recognition of spontaneous conditions and background lesions (pathology) that can influence or confound the study results. Species, strain/stock, sex, age, anatomy, physiology, spontaneous diseases (noninfectious and infectious), and neoplasia impact experimental results and interpretation as well as animal welfare. This review and the references selected aim to provide a pathology resource for researchers, pathologists, and veterinary personnel who strive to achieve research rigor and validity and must understand the spectrum of "normal" and expected conditions to accurately identify research-relevant experimental phenotypes as well as unusual illness, pathology, or other conditions that can compromise studies involving laboratory mice, rats, gerbils, guinea pigs, hamsters, naked mole rats, and rabbits.
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Affiliation(s)
- Timothy K Cooper
- Department of Comparative Medicine, Penn State Hershey Medical Center, Hershey, PA, USA
| | - David K Meyerholz
- Department of Pathology, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa, USA
| | - Amanda P Beck
- Department of Pathology, Yeshiva University Albert Einstein College of Medicine, Bronx, New York, USA
| | - Martha A Delaney
- Zoological Pathology Program, University of Illinois at Urbana-Champaign College of Veterinary Medicine, Urbana-Champaign, Illinois, USA
| | - Alessandra Piersigilli
- Laboratory of Comparative Pathology and the Genetically Modified Animal Phenotyping Service, Memorial Sloan Kettering Cancer Center, New York, New York, USA
| | - Teresa L Southard
- Department of Biomedical Sciences, Cornell University College of Veterinary Medicine, Ithaca, New York, USA
| | - Cory F Brayton
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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Allen KM, Lawlor J, Salles A, Moss CF. Orienting our view of the superior colliculus: specializations and general functions. Curr Opin Neurobiol 2021; 71:119-126. [PMID: 34826675 PMCID: PMC8996328 DOI: 10.1016/j.conb.2021.10.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 09/10/2021] [Accepted: 10/20/2021] [Indexed: 11/15/2022]
Abstract
The mammalian superior colliculus (SC) and its non-mammalian homolog, the optic tectum are implicated in sensorimotor transformations. Historically, emphasis on visuomotor functions of the SC has led to a popular view that it operates as an oculomotor structure rather than a more general orienting structure. In this review, we consider comparative work on the SC/optic tectum, with a particular focus on non-visual sensing and orienting, which reveals a broader perspective on SC functions and their role in species-specific behaviors. We highlight several recent studies that consider ethological context and natural behaviors to advance knowledge of the SC as a site of multi-sensory integration and motor initiation in diverse species.
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Affiliation(s)
- Kathryne M Allen
- Department of Psychological and Brain Sciences, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Jennifer Lawlor
- Department of Psychological and Brain Sciences, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Angeles Salles
- Department of Psychological and Brain Sciences, Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Cynthia F Moss
- Department of Psychological and Brain Sciences, Johns Hopkins University, Baltimore, MD, 21218, USA; The Solomon Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA; Department of Mechanical Engineering, Whiting School of Engineering, Johns Hopkins University, USA.
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Convergent evolution of a genomic rearrangement may explain cancer resistance in hystrico- and sciuromorpha rodents. NPJ Aging Mech Dis 2021; 7:20. [PMID: 34471123 PMCID: PMC8410860 DOI: 10.1038/s41514-021-00072-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Accepted: 06/21/2021] [Indexed: 11/09/2022] Open
Abstract
The rodents of hystricomorpha and sciuromorpha suborders exhibit remarkably lower incidence of cancer. The underlying genetic basis remains obscure. We report a convergent evolutionary split of human 3p21.31, a locus hosting a large number of tumour-suppressor genes (TSGs) and frequently deleted in several tumour types, in hystrico- and sciuromorphs. Analysis of 34 vertebrate genomes revealed that the synteny of 3p21.31 cluster is functionally and evolutionarily constrained in most placental mammals, but exhibit large genomic interruptions independently in hystricomorphs and sciuromorphs, owing to relaxation of underlying constraints. Hystrico- and sciuromorphs, therefore, escape from pro-tumorigenic co-deletion of several TSGs in cis. The split 3p21.31 sub-clusters gained proximity to proto-oncogene clusters from elsewhere, which might further nullify pro-tumorigenic impact of copy number variations due to co-deletion or co-amplification of genes with opposing effects. The split of 3p21.31 locus coincided with the accelerated rate of its gene expression and the body mass evolution of ancestral hystrico- and sciuromorphs. The genes near breakpoints were associated with the traits specific to hystrico- and sciuromorphs, implying adaptive significance. We conclude that the convergently evolved chromosomal interruptions of evolutionarily constrained 3p21.31 cluster might have impacted evolution of cancer resistance, body mass variation and ecological adaptations in hystrico- and sciuromorphs.
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9
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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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10
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Zhou X, Dou Q, Fan G, Zhang Q, Sanderford M, Kaya A, Johnson J, Karlsson EK, Tian X, Mikhalchenko A, Kumar S, Seluanov A, Zhang ZD, Gorbunova V, Liu X, Gladyshev VN. Beaver and Naked Mole Rat Genomes Reveal Common Paths to Longevity. Cell Rep 2021; 32:107949. [PMID: 32726638 DOI: 10.1016/j.celrep.2020.107949] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 02/20/2020] [Accepted: 07/02/2020] [Indexed: 11/29/2022] Open
Abstract
Long-lived rodents have become an attractive model for the studies on aging. To understand evolutionary paths to long life, we prepare chromosome-level genome assemblies of the two longest-lived rodents, Canadian beaver (Castor canadensis) and naked mole rat (NMR, Heterocephalus glaber), which were scaffolded with in vitro proximity ligation and chromosome conformation capture data and complemented with long-read sequencing. Our comparative genomic analyses reveal that amino acid substitutions at "disease-causing" sites are widespread in the rodent genomes and that identical substitutions in long-lived rodents are associated with common adaptive phenotypes, e.g., enhanced resistance to DNA damage and cellular stress. By employing a newly developed substitution model and likelihood ratio test, we find that energy and fatty acid metabolism pathways are enriched for signals of positive selection in both long-lived rodents. Thus, the high-quality genome resource of long-lived rodents can assist in the discovery of genetic factors that control longevity and adaptive evolution.
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Affiliation(s)
- Xuming Zhou
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA; Broad Institute of Harvard and MIT, Cambridge, Massachusetts, MA 02142, USA
| | - Qianhui Dou
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | | | - Quanwei Zhang
- Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Maxwell Sanderford
- Institute for Genomics and Evolutionary Medicine, Temple University, Philadelphia, PA 19122, USA
| | - Alaattin Kaya
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA; Broad Institute of Harvard and MIT, Cambridge, Massachusetts, MA 02142, USA; Department of Biology, Virginia Commonwealth University, Richmond, VA 23284 USA
| | - Jeremy Johnson
- Broad Institute of Harvard and MIT, Cambridge, Massachusetts, MA 02142, USA
| | - Elinor K Karlsson
- Broad Institute of Harvard and MIT, Cambridge, Massachusetts, MA 02142, USA; University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Xiao Tian
- Department of Biology, University of Rochester, Rochester, NY 14627, USA; Department of Medicine, University of Rochester, Rochester, NY 14627, USA
| | - Aleksei Mikhalchenko
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Sudhir Kumar
- Institute for Genomics and Evolutionary Medicine, Temple University, Philadelphia, PA 19122, USA
| | - Andrei Seluanov
- Department of Biology, University of Rochester, Rochester, NY 14627, USA; Department of Medicine, University of Rochester, Rochester, NY 14627, USA
| | | | - Vera Gorbunova
- Department of Biology, University of Rochester, Rochester, NY 14627, USA; Department of Medicine, University of Rochester, Rochester, NY 14627, USA
| | - Xin Liu
- BGI-Shenzhen, Shenzhen 518083, China
| | - Vadim N Gladyshev
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA; Broad Institute of Harvard and MIT, Cambridge, Massachusetts, MA 02142, USA.
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11
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Smith M, Buffenstein R. Managed Care of Naked Mole-Rats. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1319:381-407. [PMID: 34424526 DOI: 10.1007/978-3-030-65943-1_16] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Naked mole-rats are a burgeoning model species in the field of biomedical research and are also housed at many zoos throughout the world. These mammals possess many traits that have a large impact on the way that they are kept in captivity such as their eusociality, thermolability and lack of need for drinking water. This chapter outlines the captive care and unusual housing needs of these animals. Providing information and examples from our own experiences while working with naked mole-rats for many decades. While this chapter serves as a good framework for the captive care of this mammal species, it is in no way all-encompassing but simply reflects the way in which we have managed over many years to successfully sustain our colony of thousands of animals.
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Affiliation(s)
- Megan Smith
- Calico Life Sciences LLC, South San Francisco, 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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12
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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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13
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Touj S, Gallino D, Chakravarty MM, Bronchti G, Piché M. Structural brain plasticity induced by early blindness. Eur J Neurosci 2020; 53:778-795. [PMID: 33113245 DOI: 10.1111/ejn.15028] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Revised: 09/28/2020] [Accepted: 10/20/2020] [Indexed: 11/30/2022]
Abstract
It is well established that early blindness results in behavioural adaptations. While the functional effects of visual deprivation have been well researched, anatomical studies are scarce. The aim of this study was to investigate whole brain structural plasticity in a mouse model of congenital blindness. Volumetric analyses were conducted on high-resolution MRI images and histological sections from the same brains. These morphometric measurements were compared between anophthalmic and sighted ZRDBA mice obtained by breeding ZRDCT and DBA mice. Results from MRI analyses using the Multiple Automatically Generated Templates (MAGeT) method showed smaller volume for the primary visual cortex and superior colliculi in anophthalmic compared with sighted mice. Deformation-based morphometry revealed smaller volumes within the dorsal lateral geniculate nuclei and the lateral secondary visual cortex and larger volumes within olfactory areas, piriform cortex, orbital areas and the amygdala, in anophthalmic compared with sighted mice. Histological analyses revealed a larger volume for the amygdala and smaller volume for the superior colliculi, primary visual cortex and medial secondary visual cortex, in anophthalmic compared with sighted mice. The absence of superficial visual layers of the superior colliculus and the thinner cortical layer IV of the primary and secondary visual cortices may explain the smaller volume of these areas, although this was observed in a limited sample. The present study shows large-scale brain plasticity in a mouse model of congenital blindness. In addition, the congruence of MRI and histological findings support the use of MRI to investigate structural brain plasticity in the mouse.
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Affiliation(s)
- Sara Touj
- Department of Anatomy, Université du Québec à Trois-Rivières, Trois-Rivières, QC, Canada.,CogNAC Research Group, Université du Québec à Trois-Rivières, Trois-Rivières, QC, Canada
| | - Daniel Gallino
- Computational Brain Anatomy Laboratory, Brain Imaging Center, Douglas Mental Health University Institute, Verdun, QC, Canada
| | - Mallar M Chakravarty
- Computational Brain Anatomy Laboratory, Brain Imaging Center, Douglas Mental Health University Institute, Verdun, QC, Canada.,Department of Biological and Biomedical Engineering, McGill, Montréal, QC, Canada.,Department of Psychiatry, McGill, Montréal, QC, Canada
| | - Gilles Bronchti
- Department of Anatomy, Université du Québec à Trois-Rivières, Trois-Rivières, QC, Canada.,CogNAC Research Group, Université du Québec à Trois-Rivières, Trois-Rivières, QC, Canada
| | - Mathieu Piché
- Department of Anatomy, Université du Québec à Trois-Rivières, Trois-Rivières, QC, Canada.,CogNAC Research Group, Université du Québec à Trois-Rivières, Trois-Rivières, QC, Canada
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14
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Braude S, Holtze S, Begall S, Brenmoehl J, Burda H, Dammann P, Marmol D, Gorshkova E, Henning Y, Hoeflich A, Höhn A, Jung T, Hamo D, Sahm A, Shebzukhov Y, Šumbera R, Miwa S, Vyssokikh MY, Zglinicki T, Averina O, Hildebrandt TB. Surprisingly long survival of premature conclusions about naked mole‐rat biology. Biol Rev Camb Philos Soc 2020; 96:376-393. [DOI: 10.1111/brv.12660] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 10/06/2020] [Accepted: 10/13/2020] [Indexed: 12/11/2022]
Affiliation(s)
- Stan Braude
- Biology Department Washington University, One Brookings Drive St. Louis MO 63130 U.S.A
| | - Susanne Holtze
- Department of Reproduction Management Leibniz‐Institute for Zoo and Wildlife Research Berlin 10315 Germany
| | - Sabine Begall
- Department of General Zoology, Faculty of Biology University of Duisburg‐Essen, Universitätsstr Essen 45147 Germany
| | - Julia Brenmoehl
- Institute for Genome Biology Leibniz‐Institute for Farm Animal Biology Dummerstorf 18196 Germany
| | - Hynek Burda
- Department of Game Management and Wildlife Biology, Faculty of Forestry and Wood Sciences Czech University of Life Sciences Praha 16500 Czech Republic
| | - Philip Dammann
- Department of General Zoology, Faculty of Biology University of Duisburg‐Essen, Universitätsstr Essen 45147 Germany
- University Hospital Essen Hufelandstr Essen 45141 Germany
| | - Delphine Marmol
- Molecular Physiology Research Unit (URPhyM), NARILIS University of Namur Namur 5000 Belgium
| | - Ekaterina Gorshkova
- Engelhardt Institute of Molecular Biology Russian Academy of Sciences, Vavilova str. 32 Moscow 119991 Russia
- Faculty of Biology Lomonosov Moscow State University Moscow 119991 Russia
| | - Yoshiyuki Henning
- University Hospital Essen Hufelandstr Essen 45141 Germany
- Institute of Physiology Department of General Zoology University of Duisburg Essen Germany
| | - Andreas Hoeflich
- Division Signal Transduction Institute for Genome Biology, Leibniz‐Institute for Farm Animal Biology, FBN Dummerstorf, Wilhelm‐Stahl‐Allee 2 Dummerstorf 18196 Germany
| | - Annika Höhn
- Department of Molecular Toxicology German Institute of Human Nutrition (DIfE) Potsdam‐Rehbrücke Nuthetal 14558 Germany
- German Center for Diabetes Research (DZD) München‐Neuherberg 85764 Germany
| | - Tobias Jung
- Department of Molecular Toxicology German Institute of Human Nutrition (DIfE) Potsdam‐Rehbrücke Nuthetal 14558 Germany
| | - Dania Hamo
- Charité ‐ Universitätsmedizin Berlin Berlin Institute of Health Center for Regenerative Therapies (BCRT) Berlin 13353 Germany
- German Rheumatism Research Centre Berlin (DRFZ) Berlin 10117 Germany
| | - Arne Sahm
- Computational Biology Group Leibniz Institute on Aging – Fritz Lipmann Institute Jena 07745 Germany
| | - Yury Shebzukhov
- Engelhardt Institute of Molecular Biology Russian Academy of Sciences, Vavilova str. 32 Moscow 119991 Russia
- Charité ‐ Universitätsmedizin Berlin Berlin Institute of Health Center for Regenerative Therapies (BCRT) Berlin 13353 Germany
| | - Radim Šumbera
- Faculty of Science University of South Bohemia České Budějovice 37005 Czech Republic
| | - Satomi Miwa
- Biosciences Institute, Edwardson building, Campus for Ageing and Vitality Newcastle University Newcastle upon Tyne NE4 5PL U.K
| | - Mikhail Y. Vyssokikh
- Belozersky Institute of Physico‐Chemical Biology Lomonosov Moscow State University Moscow 119991 Russia
| | - Thomas Zglinicki
- Biosciences Institute, Edwardson building, Campus for Ageing and Vitality Newcastle University Newcastle upon Tyne NE4 5PL U.K
| | - Olga Averina
- Belozersky Institute of Physico‐Chemical Biology Lomonosov Moscow State University Moscow 119991 Russia
| | - Thomas B. Hildebrandt
- Department of Reproduction Management Leibniz‐Institute for Zoo and Wildlife Research Berlin 10315 Germany
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15
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ANESTHETIC EFFECT OF DEXMEDETOMIDINE-KETAMINEMIDAZOLAM COMBINATION ADMINISTERED INTRAMUSCULARLY TO ZOO-HOUSED NAKED MOLE-RATS ( HETEROCEPHALUS GLABER). J Zoo Wildl Med 2020; 51:59-66. [PMID: 32212547 DOI: 10.1638/2019-0121] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/25/2019] [Indexed: 11/21/2022] Open
Abstract
In this study, adult intact male and female (n = 10) naked mole-rats (Heterocephalus glaber) were anesthetized using a combination of dexmedetomidine (0.06 mg/kg intramuscularly [IM]), ketamine (20 mg/kg IM), and midazolam (1.0 mg/kg IM). Atipamezole (1.0 mg/kg IM) and flumazenil (0.1 mg/kg IM) were administered 40 min after induction. Induction and recovery times were monitored and recorded. Vital parameters, including heart rate, respiratory rate, and SpO2, and reflexes were monitored every 5 min during the anesthetic period. Anesthetic induction was smooth and rapid. All monitored reflexes were lost within a median time of 60 sec (interquartile range, 15 sec). Heart rate and respiratory rate were significantly decreased from baseline, whereas there was no difference in SpO2 over the anesthetic period. The mean time to recovery was 15 ± 7 min (mean ± SD). One animal was found dead 40 min after apparent recovery, which is suspected to be an anesthetic-related death. Based on these findings, dexmedetomidine-ketamine-midazolam anesthesia is an effective anesthetic protocol in naked mole rats that provides a consistent anesthetic plane but should be used with caution in animals with underlying conditions.
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16
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Ambar N, Eshar D, Shrader TC, Beaufrère H. Anesthetic Effects of Intramuscular Alfaxalone-Ketamine in Naked Mole Rats ( Heterocephalus glaber). JOURNAL OF THE AMERICAN ASSOCIATION FOR LABORATORY ANIMAL SCIENCE 2020; 59:539-545. [PMID: 32680579 DOI: 10.30802/aalas-jaalas-19-000170] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
In this study, adult intact male and female (n = 10) naked mole rats (Heterocephalus glaber) were anesthetized by using a combination of ketamine (20 mg/kg IM), and alfaxalone (4.0 mg/kg IM). Induction and recovery times were recorded. Vital parameters, including heart rate, respiratory rate, and reflexes, were monitored every 5 min during the anesthetic period. Anesthetic induction was smooth and rapid. Induction time was significantly longer in male rats (median, 325 s; range, 180 to 385 s) than in females (median, 145 s; range, 118 to 180 s). In addition, overall duration of loss of righting reflex was shorter in male mole rats (median, 50 min; range, 36 to 65 min) than females (median, 70 min; range, 60 to 85 min). Males largely had intact withdrawal reflexes, whereas females showed variable loss of both forelimb and hindlimb withdrawal reflexes. Neither recovery time (mean ± 1 SD, 16 ± 13 min) nor vital parameters differed between sexes. None of animals showed any anesthesia-related adverse responses. According to these findings, intramuscular AK is a safe and effective protocol that provides brief, light anesthesia in male naked mole rats and deeper anesthesia in females. We recommend adding analgesics when this AK protocol is used for pain-inducing or invasive procedures, and further studies evaluating higher doses and different combinations are indicated.
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Affiliation(s)
- Neta Ambar
- Department of Clinical Sciences, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas;,
| | - David Eshar
- Department of Clinical Sciences, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas
| | | | - Hugues Beaufrère
- Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, Canada
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17
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Eshar D, Huckins GL, Shrader TC, Beaufrère H. Comparison of intramuscular administration of alfaxalone-ketamine-dexmedetomidine and alfaxalone-butorphanol-midazolam in naked mole-rats ( Heterocephalus glaber). Am J Vet Res 2020; 80:1089-1098. [PMID: 31763939 DOI: 10.2460/ajvr.80.12.1089] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To compare anesthetic effects of alfaxalone-ketamine-dexmedetomidine (AKD) and alfaxalone-butorphanol-midazolam (ABM) in naked mole-rats (Heterocephalus glaber). ANIMALS 20 naked mole-rats. PROCEDURES Naked mole-rats received AKD (alfaxalone, 2 mg/kg; ketamine, 20 mg/kg; and dexmedetomidine, 0.02 mg/kg; n = 10) or ABM (alfaxalone, 2 mg/kg; butorphanol, 2 mg/kg; and midazolam, 1 mg/kg; 9) IM; 1 animal was removed from the study. Atipamezole (I mg/kg) and flumazenil (0.1 mg/kg) were administered 40 minutes after anesthetic induction (defined as loss of the righting reflex) with AKD and ABM, respectively. Heart rate, respiratory rate, oxygen saturation, and reflexes were recorded every 5 minutes. RESULTS The ABM group had significantly longer median times for induction and recovery than the AKD group. Administration of ABM resulted in significantly lower respiratory rates than administration of AKD from time of anesthetic induction to 10 minutes after induction. Respiratory rate significantly decreased in the AKD group from I0 minutes after induction through the end of the anesthetic period but did not change over time in the ABM group. Males had higher respiratory rates in both groups. Loss of the righting reflex was still evident 40 minutes after induction in both groups. In the AKD group, all tested reflexes were absent from I0 to 40 minutes after induction; the ABM group had variable reflexes that recovered within individual animals over time. CONCLUSIONS AND CLINICAL RELEVANCE Both AKD and ABM provided effective immobilization in naked mole-rats, but AKD appeared to provide more consistent and deeper anesthesia, compared with administration of ABM.
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18
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Braude S, Holtze S, Hildebrandt T, Koch R. Naked mole‐rats do not disperse or deliver pups in correlation with moon phase. Afr J Ecol 2020. [DOI: 10.1111/aje.12721] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Stan Braude
- Biology Department Washington University St. Louis Missouri
| | - Susanne Holtze
- Leibniz‐Instut fur Zoo und Wildtierforschung Berlin Germany
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19
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Schulze-Makuch D. The Naked Mole-Rat: An Unusual Organism with an Unexpected Latent Potential for Increased Intelligence? Life (Basel) 2019; 9:life9030076. [PMID: 31527499 PMCID: PMC6789728 DOI: 10.3390/life9030076] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 08/13/2019] [Accepted: 08/28/2019] [Indexed: 11/24/2022] Open
Abstract
Naked mole-rats are eusocial, hairless mammals that are uniquely adapted to their harsh, low-oxygen subsurface habitat. Although their encephalization quotient, a controversial marker of intelligence, is low, they exhibit many features considered tell-tale signs of highly intelligent species on our planet including longevity, plasticity, social cohesion and interaction, rudimentary language, sustainable farming abilities, and maintaining sanitary conditions in their self-built complex housing structures. It is difficult to envision how naked mole-rats would reach even higher levels of intelligence in their natural sensory-challenged habitat, but such an evolutionary path cannot be excluded if they would expand their range onto the earth’s surface.
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Affiliation(s)
- Dirk Schulze-Makuch
- Astrobiology Group, Center for Astronomy and Astrophysics (ZAA), Technical University Berlin, 10623 Berlin, Germany.
- School of the Environment, Washington State University, Pullman, WA 99163, USA.
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20
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21
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Berger MJ, Wenger AM, Guturu H, Bejerano G. Independent erosion of conserved transcription factor binding sites points to shared hindlimb, vision and external testes loss in different mammals. Nucleic Acids Res 2019; 46:9299-9308. [PMID: 30137416 PMCID: PMC6182171 DOI: 10.1093/nar/gky741] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Accepted: 08/21/2018] [Indexed: 02/05/2023] Open
Abstract
Genetic variation in cis-regulatory elements is thought to be a major driving force in morphological and physiological changes. However, identifying transcription factor binding events that code for complex traits remains a challenge, motivating novel means of detecting putatively important binding events. Using a curated set of 1154 high-quality transcription factor motifs, we demonstrate that independently eroded binding sites are enriched for independently lost traits in three distinct pairs of placental mammals. We show that these independently eroded events pinpoint the loss of hindlimbs in dolphin and manatee, degradation of vision in naked mole-rat and star-nosed mole, and the loss of external testes in white rhinoceros and Weddell seal. We additionally show that our method may also be utilized with more than two species. Our study exhibits a novel methodology to detect cis-regulatory mutations which help explain a portion of the molecular mechanism underlying complex trait formation and loss.
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Affiliation(s)
- Mark J Berger
- Department of Computer Science, Stanford University, Stanford, CA 94305-5329, USA
| | - Aaron M Wenger
- Department of Computer Science, Stanford University, Stanford, CA 94305-5329, USA
| | - Harendra Guturu
- Department of Electrical Engineering, Stanford University, Stanford, CA 94305-5008, USA
| | - Gill Bejerano
- Department of Computer Science, Stanford University, Stanford, CA 94305-5329, USA.,Department of Developmental Biology, Stanford University, Stanford, CA 94305-5329, USA.,Department of Pediatrics, Stanford University, Stanford, CA 94305-5208, USA.,Department of Biomedical Data Science, Stanford University, Stanford, CA 94305-5464, USA
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22
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Ferris E, Abegglen LM, Schiffman JD, Gregg C. Accelerated Evolution in Distinctive Species Reveals Candidate Elements for Clinically Relevant Traits, Including Mutation and Cancer Resistance. Cell Rep 2019. [PMID: 29514101 PMCID: PMC6294302 DOI: 10.1016/j.celrep.2018.02.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The identity of most functional elements in the mammalian genome and the phenotypes they impact are unclear. Here, we perform a genomewide comparative analysis of patterns of accelerated evolution in species with highly distinctive traits to discover candidate functional elements for clinically important phenotypes. We identify accelerated regions (ARs) in the elephant, hibernating bat, orca, dolphin, naked mole rat, and thirteen-lined ground squirrel lineages in mammalian conserved regions, uncovering ~33,000 elements that bind hundreds of different regulatory proteins in humans and mice. ARs in the elephant, the largest land mammal, are uniquely enriched near elephant DNA damage response genes. The genomic hotspot for elephant ARs is the E3 ligase subunit of the Fanconi anemia complex, a master regulator of DNA repair. Additionally, ARs in the six species are associated with specific human clinical phenotypes that have apparent concordance with overt traits in each species.
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Affiliation(s)
- Elliott Ferris
- Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, UT 84132-3401, USA
| | - Lisa M Abegglen
- Department of Pediatrics, University of Utah, Salt Lake City, UT 84132-3401, USA; Huntsman Cancer Institute, Salt Lake City, UT, USA
| | - Joshua D Schiffman
- Department of Pediatrics, University of Utah, Salt Lake City, UT 84132-3401, USA; Department of Oncological Sciences, University of Utah, Salt Lake City, UT 84132-3401, USA; Huntsman Cancer Institute, Salt Lake City, UT, USA
| | - Christopher Gregg
- Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, UT 84132-3401, USA; Department of Human Genetics, University of Utah, Salt Lake City, UT 84132-3401, USA; New York Stem Cell Foundation, New York, NY, USA.
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23
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Dennis JC, Stilwell NK, Smith TD, Park TJ, Bhatnagar KP, Morrison EE. Is the Mole Rat Vomeronasal Organ Functional? Anat Rec (Hoboken) 2019; 303:318-329. [DOI: 10.1002/ar.24060] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 11/02/2018] [Accepted: 12/13/2018] [Indexed: 11/06/2022]
Affiliation(s)
- John C. Dennis
- Department of Anatomy, Physiology, and Pharmacology Auburn University Auburn Alabama
| | | | - Timothy D. Smith
- School of Physical Therapy Slippery Rock University Slippery Rock Pennsylvania
- Department of Anthropology University of Pittsburgh Pittsburgh Pennsylvania
| | - Thomas J. Park
- Department of Biological Sciences University of Illinois at Chicago Chicago Illinois
| | - Kunwar P. Bhatnagar
- Department of Anatomical Sciences and Neurobiology University of Louisville School of Medicine Louisville Kentucky
| | - Edward E. Morrison
- Department of Anatomy, Physiology, and Pharmacology Auburn University Auburn Alabama
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24
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Torres CR, Clarke JA. Nocturnal giants: evolution of the sensory ecology in elephant birds and other palaeognaths inferred from digital brain reconstructions. Proc Biol Sci 2018; 285:20181540. [PMID: 30381378 PMCID: PMC6235046 DOI: 10.1098/rspb.2018.1540] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 10/10/2018] [Indexed: 11/12/2022] Open
Abstract
The recently extinct Malagasy elephant birds (Palaeognathae, Aepyornithiformes) included the largest birds that ever lived. Elephant bird neuroanatomy is understudied but can shed light on the lifestyle of these enigmatic birds. Palaeoneurological studies can provide clues to the ecologies and behaviours of extinct birds because avian brain shape is correlated with neurological function. We digitally reconstruct endocasts of two elephant bird species, Aepyornis maximus and A. hildebrandti, and compare them with representatives of all major extant and recently extinct palaeognath lineages. Among palaeognaths, we find large olfactory bulbs in taxa generally occupying forested environments where visual cues used in foraging are likely to be limited. We detected variation in olfactory bulb size among elephant bird species, possibly indicating interspecific variation in habitat. Elephant birds exhibited extremely reduced optic lobes, a condition also observed in the nocturnal kiwi. Kiwi, the sister taxon of elephant birds, have effectively replaced their visual systems with hyperdeveloped olfactory, somatosensory and auditory systems useful for foraging. We interpret these results as evidence for nocturnality among elephant birds. Vision was likely deemphasized in the ancestor of elephant birds and kiwi. These results show a previously unreported trend towards decreased visual capacity apparently exclusive to flightless, nocturnal taxa endemic to predator-depauperate islands.
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Affiliation(s)
- Christopher R Torres
- Department of Integrative Biology, University of Texas at Austin, 2415 Speedway, C0930, Austin, TX 78712, USA
| | - Julia A Clarke
- Department of Integrative Biology, University of Texas at Austin, 2415 Speedway, C0930, Austin, TX 78712, USA
- Jackson School of Geosciences, University of Texas at Austin, 2305 Speedway, C1160, Austin, TX 78712, USA
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Santana MAD, Medeiros HHA, Leite MD, Barros MAS, de Góis Morais PLA, Soares JG, Ladd FVL, Cavalcante JS, Cavalcante JC, Costa MSMO, Nascimento Jr. ES. Retinofugal Projections Into Visual Brain Structures in the Bat Artibeus planirostris: A CTb Study. Front Neuroanat 2018; 12:66. [PMID: 30135648 PMCID: PMC6092499 DOI: 10.3389/fnana.2018.00066] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Accepted: 07/23/2018] [Indexed: 01/01/2023] Open
Abstract
A well-developed visual system can provide significant sensory information to guide motor behavior, especially in fruit-eating bats, which usually use echolocation to navigate at high speed through cluttered environments during foraging. Relatively few studies have been performed to elucidate the organization of the visual system in bats. The present work provides an extensive morphological description of the retinal projections in the subcortical visual nuclei in the flat-faced fruit-eating bat (Artibeus planirostris) using anterograde transport of the eye-injected cholera toxin B subunit (CTb), followed by morphometrical and stereological analyses. Regarding the cytoarchitecture, the dorsal lateral geniculate nucleus (dLGN) was homogeneous, with no evident lamination. However, the retinal projection contained two layers that had significantly different marking intensities and a massive contralateral input. The superior colliculus (SC) was identified as a laminar structure composed of seven layers, and the retinal input was only observed on the contralateral side, targeting two most superficial layers. The medial pretectal nucleus (MPT), olivary pretectal nucleus (OPT), anterior pretectal nucleus (APT), posterior pretectal nucleus (PPT) and nucleus of the optic tract (NOT) were comprised the pretectal nuclear complex (PNT). Only the APT lacked a retinal input, which was predominantly contralateral in all other nuclei. Our results showed the morphometrical and stereological features of a bat species for the first time.
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Affiliation(s)
- Melquisedec A. D. Santana
- Laboratory of Neuroanatomy, Department of Morphology, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Helder H. A. Medeiros
- Laboratory of Neuroanatomy, Department of Morphology, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Mariana D. Leite
- Laboratory of Neuroanatomy, Department of Morphology, Federal University of Rio Grande do Norte, Natal, Brazil
| | | | | | - Joacil Germano Soares
- Laboratory of Neuroanatomy, Department of Morphology, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Fernando V. L. Ladd
- Laboratory of Neuroanatomy, Department of Morphology, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Jeferson S. Cavalcante
- Laboratory of Neurochemical Studies, Department of Physiology, Bioscience Center, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Judney C. Cavalcante
- Laboratory of Neuroanatomy, Department of Morphology, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Miriam S. M. O. Costa
- Laboratory of Neuroanatomy, Department of Morphology, Federal University of Rio Grande do Norte, Natal, Brazil
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26
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Baldwin MKL, Young NA, Matrov D, Kaas JH. Cortical projections to the superior colliculus in grey squirrels (Sciurus carolinensis). Eur J Neurosci 2018; 49:1008-1023. [PMID: 29450943 DOI: 10.1111/ejn.13867] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 01/11/2018] [Accepted: 02/02/2018] [Indexed: 01/07/2023]
Abstract
The superior colliculus is an important midbrain structure involved with integrating information from varying sensory modalities and sending motor signals to produce orienting movements towards environmental stimuli. Because of this role, the superior colliculus receives a multitude of sensory inputs from a wide variety of subcortical and cortical structures. Proportionately, the superior colliculus of grey squirrels is among the largest in size of all studied mammals, suggesting the importance of this structure in the behavioural characteristics of grey squirrels. Yet, our understanding of the connections of the superior colliculus in grey squirrels is lacking, especially with respect to possible cortical influences. In this study, we placed anatomical tracer injections within the medial aspect of the superior colliculus of five grey squirrels (Sciurus carolinensis) and analysed the areal distribution of corticotectal projecting cells in flattened cortex. V1 projections to the superior colliculus were studied in two additional animals. Our results indicate that the superior colliculus receives cortical projections from visual, higher order somatosensory, and higher order auditory regions, as well as limbic, retrosplenial and anterior cingulate cortex. Few, if any, corticotectal projections originate from primary motor, primary somatosensory or parietal cortical regions. This distribution of inputs is similar to the distribution of inputs described in other rodents such as rats and mice, yet the lack of inputs from primary somatosensory and motor cortex is features of corticotectal inputs more similar to those observed in tree shrews and primates, possibly reflecting a behavioural shift from somatosensory (vibrissae) to visual navigation.
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Affiliation(s)
- Mary K L Baldwin
- Department of Psychology, Vanderbilt University, 301 Wilson Hall, 111 21st Avenue South, Nashville, TN, 37203, USA.,Center for Neuroscience, University of California Davis, Davis, CA, USA
| | - Nicole A Young
- Department of Psychology, Vanderbilt University, 301 Wilson Hall, 111 21st Avenue South, Nashville, TN, 37203, USA.,Department of Neuroscience, College of Medicine, The Ohio State University, Columbus, OH, USA
| | - Denis Matrov
- Department of Psychology, Vanderbilt University, 301 Wilson Hall, 111 21st Avenue South, Nashville, TN, 37203, USA.,Department of Neuroscience, Graduate School of Medicine, Kyoto University, Kyoto, Japan.,Department of Neuropsychopharmacology, Institute of Psychology, University of Tartu, Tartu, Estonia
| | - Jon H Kaas
- Department of Psychology, Vanderbilt University, 301 Wilson Hall, 111 21st Avenue South, Nashville, TN, 37203, USA
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Crish SD, Schofield BR. Anterograde Tract Tracing for Assaying Axonopathy and Transport Deficits in Glaucoma. Methods Mol Biol 2018; 1695:171-185. [PMID: 29190027 DOI: 10.1007/978-1-4939-7407-8_15] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Whether to stage degeneration or investigate early pathology in glaucoma, examination of axonal structure and function is essential. There are a wide variety of methods available to investigators using animal models of glaucoma, with varying utilities depending on the questions asked. Here, we describe the use of anterograde neuronal tract tracing using cholera toxin B (CTB) for the determination of axon transport integrity of the retinofugal projection. This method reveals the structure of the retinal axons as well as the functional integrity of anterograde transport systems.
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Affiliation(s)
- Samuel D Crish
- Department of Pharmaceutical Sciences, Northeast Ohio Medical University, RGE-135, 4209 St. Rt. 44, Rootstown, OH, 44272, USA.
| | - Brett R Schofield
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH, 44272, USA
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Scholl B, Rylee J, Luci JJ, Priebe NJ, Padberg J. Orientation selectivity in the visual cortex of the nine-banded armadillo. J Neurophysiol 2017; 117:1395-1406. [PMID: 28053246 DOI: 10.1152/jn.00851.2016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 01/03/2017] [Accepted: 01/03/2017] [Indexed: 12/28/2022] Open
Abstract
Orientation selectivity in primary visual cortex (V1) has been proposed to reflect a canonical computation performed by the neocortical circuitry. Although orientation selectivity has been reported in all mammals examined to date, the degree of selectivity and the functional organization of selectivity vary across mammalian clades. The differences in degree of orientation selectivity are large, from reports in marsupials that only a small subset of neurons are selective to studies in carnivores, in which it is rare to find a neuron lacking selectivity. Furthermore, the functional organization in cortex varies in that the primate and carnivore V1 is characterized by an organization in which nearby neurons share orientation preference while other mammals such as rodents and lagomorphs either lack or have only extremely weak clustering. To gain insight into the evolutionary emergence of orientation selectivity, we examined the nine-banded armadillo, a species within the early placental clade Xenarthra. Here we use a combination of neuroimaging, histological, and electrophysiological methods to identify the retinofugal pathways, locate V1, and for the first time examine the functional properties of V1 neurons in the armadillo (Dasypus novemcinctus) V1. Individual neurons were strongly sensitive to the orientation and often the direction of drifting gratings. We uncovered a wide range of orientation preferences but found a bias for horizontal gratings. The presence of strong orientation selectivity in armadillos suggests that the circuitry responsible for this computation is common to all placental mammals.NEW & NOTEWORTHY The current study shows that armadillo primary visual cortex (V1) neurons share the signature properties of V1 neurons of primates, carnivorans, and rodents. Furthermore, these neurons exhibit a degree of selectivity for stimulus orientation and motion direction similar to that found in primate V1. Our findings in armadillo visual cortex suggest that the functional properties of V1 neurons emerged early in the mammalian lineage, near the time of the divergence of marsupials.
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Affiliation(s)
| | - Johnathan Rylee
- Department of Biology, University of Central Arkansas, Conway, Arkansas
| | - Jeffrey J Luci
- Department of Neuroscience, The University of Texas at Austin, Austin, Texas; and
| | - Nicholas J Priebe
- Department of Neuroscience, The University of Texas at Austin, Austin, Texas; and.,Center for Learning and Memory, Center for Perceptual Systems, The University of Texas at Austin, Austin, Texas
| | - Jeffrey Padberg
- Department of Biology, University of Central Arkansas, Conway, Arkansas;
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Selective binocular vision loss in two subterranean caviomorph rodents: Spalacopus cyanus and Ctenomys talarum. Sci Rep 2017; 7:41704. [PMID: 28150809 PMCID: PMC5288697 DOI: 10.1038/srep41704] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Accepted: 12/19/2016] [Indexed: 11/09/2022] Open
Abstract
To what extent can the mammalian visual system be shaped by visual behavior? Here we analyze the shape of the visual fields, the densities and distribution of cells in the retinal ganglion-cell layer and the organization of the visual projections in two species of facultative non-strictly subterranean rodents, Spalacopus cyanus and Ctenomys talarum, aiming to compare these traits with those of phylogenetically closely related species possessing contrasting diurnal/nocturnal visual habits. S. cyanus shows a definite zone of frontal binocular overlap and a corresponding area centralis, but a highly reduced amount of ipsilateral retinal projections. The situation in C. talarum is more extreme as it lacks of a fronto-ventral area of binocular superposition, has no recognizable area centralis and shows no ipsilateral retinal projections except to the suprachiasmatic nucleus. In both species, the extension of the monocular visual field and of the dorsal region of binocular overlap as well as the whole set of contralateral visual projections, appear well-developed. We conclude that these subterranean rodents exhibit, paradoxically, diurnal instead of nocturnal visual specializations, but at the same time suffer a specific regression of the anatomical substrate for stereopsis. We discuss these findings in light of the visual ecology of subterranean lifestyles.
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30
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Haupt M, Bennett NC, Oosthuizen MK. Locomotor Activity and Body Temperature Patterns over a Temperature Gradient in the Highveld Mole-Rat (Cryptomys hottentotus pretoriae). PLoS One 2017; 12:e0169644. [PMID: 28072840 PMCID: PMC5224861 DOI: 10.1371/journal.pone.0169644] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Accepted: 12/20/2016] [Indexed: 11/21/2022] Open
Abstract
African mole-rats are strictly subterranean mammals that live in extensive burrow systems. High humidity levels in the burrows prevent mole-rats from thermoregulating using evaporative cooling. However, the relatively stable environment of the burrows promotes moderate temperatures and small daily temperature fluctuations. Mole-rats therefore display a relatively wide range of thermoregulation abilities. Some species cannot maintain their body temperatures at a constant level, whereas others employ behavioural thermoregulation. Here we test the effect of ambient temperature on locomotor activity and body temperature, and the relationship between the two parameters, in the highveld mole-rat. We exposed mole-rats to a 12L:12D and a DD light cycle at ambient temperatures of 30°C, 25°C and 20°C while locomotor activity and body temperature were measured simultaneously. In addition, we investigated the endogenous rhythms of locomotor activity and body temperature at different ambient temperatures. Mole-rats displayed nocturnal activity at all three ambient temperatures and were most active at 20°C, but least active at 30°C. Body temperature was highest at 30°C and lowest at 20°C, and the daily cycle was highly correlated with locomotor activity. We show that the mole-rats have endogenous rhythms for both locomotor activity and body temperature. However, the endogenous body temperature rhythm appears to be less robust compared to the locomotor activity rhythm. Female mole-rats appear to be more sensitive to temperature changes than males, increased heterothermy is evident at lower ambient temperatures, whilst males show smaller variation in their body temperatures with changing ambient temperatures. Mole-rats may rely more heavily on behavioural thermoregulation as it is more energy efficient in an already challenging environment.
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Affiliation(s)
- Meghan Haupt
- Department of Zoology & Entomology, University of Pretoria, Pretoria, South Africa
| | - Nigel C. Bennett
- Department of Zoology & Entomology, University of Pretoria, Pretoria, South Africa
| | - Maria K. Oosthuizen
- Department of Zoology & Entomology, University of Pretoria, Pretoria, South Africa
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31
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Kott O, Němec P, Fremlová A, Mazoch V, Šumbera R. Behavioural Tests Reveal Severe Visual Deficits in the Strictly Subterranean African Mole-Rats (Bathyergidae) but Efficient Vision in the Fossorial Rodent Coruro (Spalacopus cyanus, Octodontidae). Ethology 2016. [DOI: 10.1111/eth.12515] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ondřej Kott
- Department of Zoology; Faculty of Science; University of South Bohemia; České Budějovice Czech Republic
| | - Pavel Němec
- Department of Zoology; Faculty of Science; Charles University in Prague; Prague Czech Republic
| | - Aneta Fremlová
- Department of Zoology; Faculty of Science; University of South Bohemia; České Budějovice Czech Republic
| | - Vladimír Mazoch
- Department of Zoology; Faculty of Science; University of South Bohemia; České Budějovice Czech Republic
| | - Radim Šumbera
- Department of Zoology; Faculty of Science; University of South Bohemia; České Budějovice Czech Republic
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32
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Corfield JR, Kolominsky J, Craciun I, Mulvany-Robbins BE, Wylie DR. Is Cerebellar Architecture Shaped by Sensory Ecology in the New Zealand Kiwi (Apteryx mantelli). BRAIN, BEHAVIOR AND EVOLUTION 2016; 87:88-104. [PMID: 27192984 DOI: 10.1159/000445315] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 03/09/2016] [Indexed: 11/19/2022]
Abstract
Among some mammals and birds, the cerebellar architecture appears to be adapted to the animal's ecological niche, particularly their sensory ecology and behavior. This relationship is, however, not well understood. To explore this, we examined the expression of zebrin II (ZII) in the cerebellum of the kiwi (Apteryx mantelli), a fully nocturnal bird with auditory, tactile, and olfactory specializations and a reduced visual system. We predicted that the cerebellar architecture, particularly those regions receiving visual inputs and those that receive trigeminal afferents from their beak, would be modified in accordance with their unique way of life. The general stripe-and-transverse region architecture characteristic of birds is present in kiwi, with some differences. Folium IXcd was characterized by large ZII-positive stripes and all Purkinje cells in the flocculus were ZII positive, features that resemble those of small mammals and suggest a visual ecology unlike that of other birds. The central region in kiwi appeared reduced or modified, with folium IV containing ZII+/- stripes, unlike that of most birds, but similar to that of Chilean tinamous. It is possible that a reduced visual system has contributed to a small central region, although increased trigeminal input and flightlessness have undoubtedly played a role in shaping its architecture. Overall, like in mammals, the cerebellar architecture in kiwi and other birds may be substantially modified to serve a particular ecological niche, although we still require a larger comparative data set to fully understand this relationship.
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Affiliation(s)
- Jeremy R Corfield
- Department of Biological Sciences, Salisbury University, Salisbury, Md., USA
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33
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Wilkens H. Genetics and hybridization in surface and caveAstyanax(Teleostei): a comparison of regressive and constructive traits. Biol J Linn Soc Lond 2016. [DOI: 10.1111/bij.12773] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Horst Wilkens
- University of Hamburg; Centrum für Naturkunde - CeNak; Zoological Museum; Martin-Luther-King-Platz 3 20146 Hamburg Germany
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34
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Gessele N, Garcia-Pino E, Omerbašić D, Park TJ, Koch U. Structural Changes and Lack of HCN1 Channels in the Binaural Auditory Brainstem of the Naked Mole-Rat (Heterocephalus glaber). PLoS One 2016; 11:e0146428. [PMID: 26760498 PMCID: PMC4711988 DOI: 10.1371/journal.pone.0146428] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Accepted: 12/15/2015] [Indexed: 11/22/2022] Open
Abstract
Naked mole-rats (Heterocephalus glaber) live in large eu-social, underground colonies in narrow burrows and are exposed to a large repertoire of communication signals but negligible binaural sound localization cues, such as interaural time and intensity differences. We therefore asked whether monaural and binaural auditory brainstem nuclei in the naked mole-rat are differentially adjusted to this acoustic environment. Using antibody stainings against excitatory and inhibitory presynaptic structures, namely the vesicular glutamate transporter VGluT1 and the glycine transporter GlyT2 we identified all major auditory brainstem nuclei except the superior paraolivary nucleus in these animals. Naked mole-rats possess a well structured medial superior olive, with a similar synaptic arrangement to interaural-time-difference encoding animals. The neighboring lateral superior olive, which analyzes interaural intensity differences, is large and elongated, whereas the medial nucleus of the trapezoid body, which provides the contralateral inhibitory input to these binaural nuclei, is reduced in size. In contrast, the cochlear nucleus, the nuclei of the lateral lemniscus and the inferior colliculus are not considerably different when compared to other rodent species. Most interestingly, binaural auditory brainstem nuclei lack the membrane-bound hyperpolarization-activated channel HCN1, a voltage-gated ion channel that greatly contributes to the fast integration times in binaural nuclei of the superior olivary complex in other species. This suggests substantially lengthened membrane time constants and thus prolonged temporal integration of inputs in binaural auditory brainstem neurons and might be linked to the severely degenerated sound localization abilities in these animals.
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Affiliation(s)
- Nikodemus Gessele
- Neurophysiology, Institute of Biology, Freie Universität Berlin, Berlin, Germany
| | - Elisabet Garcia-Pino
- Neurophysiology, Institute of Biology, Freie Universität Berlin, Berlin, Germany
| | - Damir Omerbašić
- Department of Neuroscience, Max-Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Thomas J. Park
- Laboratory of Integrative Neuroscience, Department of Biological Sciences, University of Illinois at Chicago, Chicago, Illinois, United States of America
| | - Ursula Koch
- Neurophysiology, Institute of Biology, Freie Universität Berlin, Berlin, Germany
- * E-mail:
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Smith TD, Laitman JT, Bhatnagar KP. The shrinking anthropoid nose, the human vomeronasal organ, and the language of anatomical reduction. Anat Rec (Hoboken) 2015; 297:2196-204. [PMID: 25312373 DOI: 10.1002/ar.23035] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Accepted: 06/25/2014] [Indexed: 11/09/2022]
Abstract
Humans and most of our closest extant relatives, the anthropoids, are notable for their reduced "snout." The striking reduction in facial projection is only a superficial similarity. All anthropoids, including those with long faces (e.g., baboons), have lost numerous internal projections (turbinals) and spaces (recesses). In sum, this equates to the loss of certain regions of olfactory mucosa in anthropoids. In addition, an accessory olfactory organ, the vomeronasal organ, is non-functional or even absent in all catarrhine primates (humans, apes, monkeys). In this commentary, we revisit the concept of anatomical reductions as it pertains to the anthropoid nasal region. Certain nasal structures and spaces in anthropoids exhibit well-known attributes of other known vestiges, such as variability in form or number. The cupular recess (a vestige of the olfactory recess) and some rudimentary ethmoturbinals constitute reduced structures that presumably were fully functional in our ancestors. Humans and at least some apes retain a vestige that is bereft of chemosensory function (while in catarrhine monkeys it is completely absent). However, the function of the vomeronasal system also includes prenatal roles, which may be common to most or all mammals. Notably, neurons migrate to the brain along vomeronasal and terminal nerve axons during embryogenesis. The time-specific role of the VNO raises the possibility that our concept of functional reduction is too static. The vomeronasal system of humans and other catarrhine primates appears to qualify as a "chronological" vestige, one which fulfills part of its function during ontogeny, and then becomes lost or vestigial.
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Affiliation(s)
- Timothy D Smith
- School of Physical Therapy, Slippery Rock University, Slippery Rock, Pennsylvania; Department of Anthropology, University of Pittsburgh, Pittsburgh, Pennsylvania
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36
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Congenital blindness affects diencephalic but not mesencephalic structures in the human brain. Brain Struct Funct 2015; 221:1465-80. [DOI: 10.1007/s00429-014-0984-5] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Accepted: 12/28/2014] [Indexed: 11/26/2022]
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Homman-Ludiye J, Bourne JA. Mapping arealisation of the visual cortex of non-primate species: lessons for development and evolution. Front Neural Circuits 2014; 8:79. [PMID: 25071460 PMCID: PMC4081835 DOI: 10.3389/fncir.2014.00079] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Accepted: 06/19/2014] [Indexed: 01/08/2023] Open
Abstract
The integration of the visual stimulus takes place at the level of the neocortex, organized in anatomically distinct and functionally unique areas. Primates, including humans, are heavily dependent on vision, with approximately 50% of their neocortical surface dedicated to visual processing and possess many more visual areas than any other mammal, making them the model of choice to study visual cortical arealisation. However, in order to identify the mechanisms responsible for patterning the developing neocortex, specifying area identity as well as elucidate events that have enabled the evolution of the complex primate visual cortex, it is essential to gain access to the cortical maps of alternative species. To this end, species including the mouse have driven the identification of cellular markers, which possess an area-specific expression profile, the development of new tools to label connections and technological advance in imaging techniques enabling monitoring of cortical activity in a behaving animal. In this review we present non-primate species that have contributed to elucidating the evolution and development of the visual cortex. We describe the current understanding of the mechanisms supporting the establishment of areal borders during development, mainly gained in the mouse thanks to the availability of genetically modified lines but also the limitations of the mouse model and the need for alternate species.
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Affiliation(s)
- Jihane Homman-Ludiye
- Bourne Group, Australian Regenerative Medicine Institute, Monash University Clayton, VIC, Australia
| | - James A Bourne
- Bourne Group, Australian Regenerative Medicine Institute, Monash University Clayton, VIC, Australia
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Molnár Z, Kaas JH, de Carlos JA, Hevner RF, Lein E, Němec P. Evolution and development of the mammalian cerebral cortex. BRAIN, BEHAVIOR AND EVOLUTION 2014; 83:126-39. [PMID: 24776993 PMCID: PMC4440552 DOI: 10.1159/000357753] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Accepted: 12/03/2013] [Indexed: 12/20/2022]
Abstract
Comparative developmental studies of the mammalian brain can identify key changes that can generate the diverse structures and functions of the brain. We have studied how the neocortex of early mammals became organized into functionally distinct areas, and how the current level of cortical cellular and laminar specialization arose from the simpler premammalian cortex. We demonstrate the neocortical organization in early mammals, which helps to elucidate how the large, complex human brain evolved from a long line of ancestors. The radial and tangential enlargement of the cortex was driven by changes in the patterns of cortical neurogenesis, including alterations in the proportions of distinct progenitor types. Some cortical cell populations travel to the cortex through tangential migration whereas others migrate radially. A number of recent studies have begun to characterize the chick, mouse and human and nonhuman primate cortical transcriptome to help us understand how gene expression relates to the development and anatomical and functional organization of the adult neocortex. Although all mammalian forms share the basic layout of cortical areas, the areal proportions and distributions are driven by distinct evolutionary pressures acting on sensory and motor experiences during the individual ontogenies.
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Affiliation(s)
- Zoltán Molnár
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
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39
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Eye development in the Cape dune mole rat. Dev Genes Evol 2014; 224:107-17. [PMID: 24570380 DOI: 10.1007/s00427-014-0468-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Accepted: 01/28/2014] [Indexed: 10/25/2022]
Abstract
Studies on mammalian species with naturally reduced eyes can provide valuable insights into the evolutionary developmental mechanisms underlying the reduction of the eye structures. Because few naturally microphthalmic animals have been studied and eye reduction must have evolved independently in many of the modern groups, novel evolutionary developmental models for eye research have to be sought. Here, we present a first report on embryonic eye development in the Cape dune mole rat, Bathyergus suillus. The eyes of these animals contain all the internal structures characteristic of the normal eye but exhibit abnormalities in the anterior chamber structures. The lens is small but develops normally and exhibits a normal expression of α- and γ-crystallins. One of the interesting features of these animals is an extremely enlarged and highly pigmented ciliary body. In order to understand the molecular basis of this unusual feature, the expression pattern of an early marker of the ciliary zone, Ptmb4, was investigated in this animal. Surprisingly, in situ hybridization results revealed that Ptmb4 expression was absent from the ciliary body zone of the developing Bathyergus eye.
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Seki F, Hikishima K, Nambu S, Okanoya K, Okano HJ, Sasaki E, Miura K, Okano H. Multidimensional MRI-CT atlas of the naked mole-rat brain (Heterocephalus glaber). Front Neuroanat 2013; 7:45. [PMID: 24391551 PMCID: PMC3868886 DOI: 10.3389/fnana.2013.00045] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Accepted: 11/27/2013] [Indexed: 11/13/2022] Open
Abstract
Naked mole-rats have a variety of distinctive features such as the organization of a hierarchical society (known as eusociality), extraordinary longevity, and cancer resistance; thus, it would be worthwhile investigating these animals in detail. One important task is the preparation of a brain atlas database that provide comprehensive information containing multidimensional data with various image contrasts, which can be achievable using a magnetic resonance imaging (MRI). Advanced MRI techniques such as diffusion tensor imaging (DTI), which generates high contrast images of fiber structures, can characterize unique morphological properties in addition to conventional MRI. To obtain high spatial resolution images, MR histology, DTI, and X-ray computed tomography were performed on the fixed adult brain. Skull and brain structures were segmented as well as reconstructed in stereotaxic coordinates. Data were also acquired for the neonatal brain to allow developmental changes to be observed. Moreover, in vivo imaging of naked mole-rats was established as an evaluation tool of live animals. The data obtained comprised three-dimensional (3D) images with high tissue contrast as well as stereotaxic coordinates. Developmental differences in the visual system were highlighted in particular by DTI. Although it was difficult to delineate optic nerves in the mature adult brain, parts of them could be distinguished in the immature neonatal brain. From observation of cortical thickness, possibility of high somatosensory system development replaced to the visual system was indicated. 3D visualization of brain structures in the atlas as well as the establishment of in vivo imaging would promote neuroimaging researches towards detection of novel characteristics of eusocial naked mole-rats.
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Affiliation(s)
- Fumiko Seki
- Department of Physiology, Keio University School of Medicine Tokyo, Japan ; Central Institute for Experimental Animals Kanagawa, Japan
| | - Keigo Hikishima
- Department of Physiology, Keio University School of Medicine Tokyo, Japan ; Central Institute for Experimental Animals Kanagawa, Japan
| | - Sanae Nambu
- Laboratory for Symbolic Cognitive Development, RIKEN Brain Science Institute Saitama, Japan
| | - Kazuo Okanoya
- Japan Science and Technology Exploratory Research for Advanced Technology Okanoya Emotional Information Project Saitama, Japan ; Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo Tokyo, Japan
| | - Hirotaka J Okano
- Division of Regenerative Medicine, Jikei University School of Medicine, Tokyo, Japan
| | - Erika Sasaki
- Department of Physiology, Keio University School of Medicine Tokyo, Japan ; Central Institute for Experimental Animals Kanagawa, Japan
| | - Kyoko Miura
- Department of Physiology, Keio University School of Medicine Tokyo, Japan ; Precursory Research for Embryonic Science and Technology, Japan Science and Technology Saitama, Japan
| | - Hideyuki Okano
- Department of Physiology, Keio University School of Medicine Tokyo, Japan ; Riken Keio University Joint Research Laboratory, RIKEN Brain Science Institute Saitama, Japan
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Sarko DK, Leitch DB, Catania KC. Cutaneous and periodontal inputs to the cerebellum of the naked mole-rat (Heterocephalus glaber). Front Neuroanat 2013; 7:39. [PMID: 24302898 PMCID: PMC3831171 DOI: 10.3389/fnana.2013.00039] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Accepted: 10/25/2013] [Indexed: 11/20/2022] Open
Abstract
The naked mole-rat (Heterocephalus glaber) is a small fossorial rodent with specialized dentition that is reflected by the large cortical area dedicated to representation of the prominent incisors. Due to naked mole-rats’ behavioral reliance on the incisors for digging and for manipulating objects, as well as their ability to move the lower incisors independently, we hypothesized that expanded somatosensory representations of the incisors would be present within the cerebellum in order to accommodate a greater degree of proprioceptive, cutaneous, and periodontal input. Multiunit electrophysiological recordings targeting the ansiform lobule were used to investigate tactile inputs from receptive fields on the entire body with a focus on the incisors. Similar to other rodents, a fractured somatotopy appeared to be present with discrete representations of the same receptive fields repeated within each folium of the cerebellum. These findings confirm the presence of somatosensory inputs to a large area of the naked mole-rat cerebellum with particularly extensive representations of the lower incisors and mystacial vibrissae. We speculate that these extensive inputs facilitate processing of tactile cues as part of a sensorimotor integration network that optimizes how sensory stimuli are acquired through active exploration and in turn adjusts motor outputs (such as independent movement of the lower incisors). These results highlight the diverse sensory specializations and corresponding brain organizational schemes that have evolved in different mammals to facilitate exploration of and interaction with their environment.
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Affiliation(s)
- Diana K Sarko
- Department of Anatomy, Cell Biology and Physiology, Edward Via College of Osteopathic Medicine Spartanburg, SC, USA
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Gaillard F, Karten HJ, Sauvé Y. Retinorecipient areas in the diurnal murine rodentArvicanthis niloticus: A disproportionally large superior colliculus. J Comp Neurol 2013; 521:1699-726. [DOI: 10.1002/cne.23303] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2012] [Revised: 07/01/2012] [Accepted: 01/04/2013] [Indexed: 12/24/2022]
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Marzban H, Hoy N, Aavani T, Sarko DK, Catania KC, Hawkes R. Compartmentation of the cerebellar cortex in the naked mole-rat (Heterocephalus glaber). THE CEREBELLUM 2012; 10:435-48. [PMID: 21298580 DOI: 10.1007/s12311-011-0251-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Despite the apparent uniformity in cellular composition of the adult mammalian cerebellar cortex, it is actually highly compartmentalized into transverse zones and within each zone further subdivided into a reproducible array of parasagittal stripes. This basic cerebellar architecture is highly conserved in birds and mammals. However, different species have very different cerebellar morphologies, and it is unclear if cerebellar architecture reflects taxonomic relations or ecological niches. To explore this, we have examined the cerebellum of the naked mole-rat Heterocephalus glaber, a burrowing rodent with adaptations to a subterranean life that include only a rudimentary visual system. The cerebellum of H. glaber resembles that of other rodents with the remarkable exception that cerebellar regions that are prominent in the handling of visual information (the central zone, nodular zone, and dorsal paraflocculus) are greatly reduced or absent. In addition, there is a notable increase in size in the posterior zone, consistent with an expanded role for the trigeminal somatosensory system. These data suggest that cerebellar architecture may be substantially modified to serve a particular ecological niche.
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Affiliation(s)
- Hassan Marzban
- Department of Cell Biology and Anatomy, Hotchkiss Brain Institute, and Genes and Development Research Group, Faculty of Medicine, University of Calgary, 3330 Hospital Drive N.W., Calgary, AB, T2N 4N1, Canada
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Abstract
Naked mole rats are mouse-sized rodents that have become an important animal model in biomedical research. They play a unique mammalian role in behavioral and ecophysiological research of life underground. This chapter studies the general physiology, anatomy of organ systems, husbandry, and uses in research of the naked mole rats. Naked mole rats belong to the order Rodentia in that they have two incisor teeth on the upper and lower arcade that continuously grow. The skin is loose, wrinkled, and brownish pink in color. The body is for the most part absent of hairs with the exception of tactile hairs that are regularly arranged throughout the body and which are particularly prominent around the face and to a lesser extent on the tail. They are typically housed at 28–30°C, and at 50–60% relative humidity. Because naked mole rats are social and have cooperative behaviors, the study of their conduct has more applicability to people. The chapter describes the models of experimental research on the naked mole rat such as the model of reproductive suppression, model of somatosensory processing, model of bone elongation, and model of aging.
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Corfield JR, Gsell AC, Brunton D, Heesy CP, Hall MI, Acosta ML, Iwaniuk AN. Anatomical specializations for nocturnality in a critically endangered parrot, the Kakapo (Strigops habroptilus). PLoS One 2011; 6:e22945. [PMID: 21860663 PMCID: PMC3157909 DOI: 10.1371/journal.pone.0022945] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2011] [Accepted: 07/05/2011] [Indexed: 11/19/2022] Open
Abstract
The shift from a diurnal to nocturnal lifestyle in vertebrates is generally associated with either enhanced visual sensitivity or a decreased reliance on vision. Within birds, most studies have focused on differences in the visual system across all birds with respect to nocturnality-diurnality. The critically endangered Kakapo (Strigops habroptilus), a parrot endemic to New Zealand, is an example of a species that has evolved a nocturnal lifestyle in an otherwise diurnal lineage, but nothing is known about its' visual system. Here, we provide a detailed morphological analysis of the orbits, brain, eye, and retina of the Kakapo and comparisons with other birds. Morphometric analyses revealed that the Kakapo's orbits are significantly more convergent than other parrots, suggesting an increased binocular overlap in the visual field. The Kakapo exhibits an eye shape that is consistent with other nocturnal birds, including owls and nightjars, but is also within the range of the diurnal parrots. With respect to the brain, the Kakapo has a significantly smaller optic nerve and tectofugal visual pathway. Specifically, the optic tectum, nucleus rotundus and entopallium were significantly reduced in relative size compared to other parrots. There was no apparent reduction to the thalamofugal visual pathway. Finally, the retinal morphology of the Kakapo is similar to that of both diurnal and nocturnal birds, suggesting a retina that is specialised for a crepuscular niche. Overall, this suggests that the Kakapo has enhanced light sensitivity, poor visual acuity and a larger binocular field than other parrots. We conclude that the Kakapo possesses a visual system unlike that of either strictly nocturnal or diurnal birds and therefore does not adhere to the traditional view of the evolution of nocturnality in birds.
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Affiliation(s)
- Jeremy R Corfield
- Department of Neuroscience, University of Lethbridge, Lethbridge, Alberta, Canada.
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Sarko DK, Rice FL, Reep RL. Mammalian tactile hair: divergence from a limited distribution. Ann N Y Acad Sci 2011; 1225:90-100. [DOI: 10.1111/j.1749-6632.2011.05979.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Expression pattern of cadherins in the naked mole rat (Heterocephalus glaber) suggests innate cortical diversification of the cerebrum. J Comp Neurol 2011; 519:1736-47. [DOI: 10.1002/cne.22598] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Oosthuizen MK, Bennett NC, Cooper HM. PHOTIC INDUCTION OF Fos IN THE SUPRACHIASMATIC NUCLEUS OF AFRICAN MOLE-RATS: RESPONSES TO INCREASING IRRADIANCE. Chronobiol Int 2010; 27:1532-45. [DOI: 10.3109/07420528.2010.510227] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Maria K. Oosthuizen
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa
| | - Nigel C. Bennett
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa
| | - Howard M. Cooper
- Stem Cell and Brain Research Institute, Department of Chronobiology, INSERM, U846, Bron, France
- University of Lyon, Lyon I, Lyon, France
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McMullen CA, Andrade FH, Crish SD. Underdeveloped extraocular muscles in the naked mole-rat (Heterocephalus glaber). Anat Rec (Hoboken) 2010; 293:918-23. [PMID: 20186962 DOI: 10.1002/ar.21107] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The extraocular muscles (EOM), the effector arm of the ocular motor system, have a unique embryological origin and phenotype. The naked mole-rat (NMR) is a subterranean rodent with an underdeveloped visual system. It has not been established if their ocular motor system is also less developed. The NMR is an ideal model to examine the potential codependence of oculomotor and visual system development and evolution. Our goal was to compare the structural features of NMR EOMs to those of the mouse, a similar sized rodent with a fully developed visual system. Perfusion-fixed whole orbits and EOMs were dissected from adult NMR and C57BL mice and examined by light and electron microscopy. NMR orbital anatomy showed smaller EOMs in roughly the same distribution around the eye as in mouse and surrounded by a very small Harderian gland. The NMR EOMs did not appear to have the two-layer fiber distribution seen in mouse EOMs; fibers were also significantly smaller (112.3 +/- 46.2 vs. 550.7 +/- 226 sq microm in mouse EOMs, *P < 0.05). Myofibrillar density was less in NMR EOMs, and triad and other membranous structures were rudimentary. Finally, mitochondrial volume density was significantly less in NMR EOMs than in mouse EOM (4.5% +/- 1.9 vs. 21.2% +/- 11.6, respectively, *P < 0.05). These results demonstrate that NMR EOMs are smaller and less organized than those in the mouse. The "simpler" EOM organization and structure in NMR may be explained by the poor visual ability of these rodents, initially demonstrated by their primitive visual system.
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Affiliation(s)
- Colleen A McMullen
- Departments of Physiology, University of Kentucky, Lexington, Kentucky, USA.
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Kott O, Šumbera R, Němec P. Light perception in two strictly subterranean rodents: life in the dark or blue? PLoS One 2010; 5:e11810. [PMID: 20676369 PMCID: PMC2911378 DOI: 10.1371/journal.pone.0011810] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2010] [Accepted: 06/23/2010] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND The African mole-rats (Bathyergidae, Rodentia) are strictly subterranean, congenitally microphthalmic rodents that are hardly ever exposed to environmental light. Because of the lack of an overt behavioural reaction to light, they have long been considered to be blind. However, recent anatomical studies have suggested retention of basic visual capabilities. In this study, we employed behavioural tests to find out if two mole-rat species are able to discriminate between light and dark, if they are able to discriminate colours and, finally, if the presence of light in burrows provokes plugging behaviour, which is assumed to have a primarily anti-predatory function. METHODOLOGY/PRINCIPAL FINDING We used a binary choice test to show that the silvery mole-rat Heliophobius argenteocinereus and the giant mole-rat Fukomys mechowii exhibit a clear photoavoidance response to full-spectrum ("white"), blue and green-yellow light, but no significant reaction to ultraviolet or red light during nest building. The mole-rats thus retain dark/light discrimination capabilities and a capacity to perceive short to medium-wavelength light in the photopic range of intensities. These findings further suggest that the mole-rat S opsin has its absorption maximum in the violet/blue part of the spectrum. The assay did not yield conclusive evidence regarding colour discrimination. To test the putative role of vision in bathyergid anti-predatory behaviour, we examined the reaction of mole-rats to the incidence of light in an artificial burrow system. The presence of light in the burrow effectively induced plugging of the illuminated tunnel. CONCLUSION/SIGNIFICANCE Our findings suggest that the photopic vision is conserved and that low acuity residual vision plays an important role in predator avoidance and tunnel maintenance in the African mole-rats.
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Affiliation(s)
- Ondřej Kott
- Department of Zoology, Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
| | - Radim Šumbera
- Department of Zoology, Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
| | - Pavel Němec
- Department of Zoology, Faculty of Science, Charles University in Prague, Prague, Czech Republic
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