1
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Blanco MB, Greene LK, Welser KH, Ehmke EE, Yoder AD, Klopfer PH. Primate hibernation: The past, present, and promise of captive dwarf lemurs. Ann N Y Acad Sci 2024. [PMID: 39137248 DOI: 10.1111/nyas.15206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/15/2024]
Abstract
The dwarf lemurs (Cheirogaleus spp.) of Madagascar are the only obligate hibernators among primates. Despite century-old field accounts of seasonal lethargy, and more recent evidence of hibernation in the western fat-tailed dwarf lemur (Cheirogaleus medius), inducing hibernation in captivity remained elusive for decades. This included the Duke Lemur Center (DLC), which maintains fat-tailed dwarf lemurs and has produced sporadic research on reproduction and metabolism. With cumulative knowledge from the field, a newly robust colony, and better infrastructure, we recently induced hibernation in DLC dwarf lemurs. We describe two follow-up experiments in subsequent years. First, we show that dwarf lemurs under stable cold conditions (13°C) with available food continued to eat daily, expressed shallower and shorter torpor bouts, and had a modified gut microbiome compared to peers without food. Second, we demonstrate that dwarf lemurs under fluctuating temperatures (12-30°C) can passively rewarm daily, which was associated with altered patterns of fat depletion and reduced oxidative stress. Despite the limitations of working with endangered primates, we highlight the promise of studying hibernation in captive dwarf lemurs. Follow-up studies on genomics and epigenetics, metabolism, and endocrinology could have relevance across multidisciplinary fields, from biomedicine to evolutionary biology, and conservation.
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Affiliation(s)
- Marina B Blanco
- Department of Biology, Duke University, Durham, North Carolina, USA
- Duke Lemur Center, Duke University, Durham, North Carolina, USA
| | - Lydia K Greene
- Department of Biology, Duke University, Durham, North Carolina, USA
- Duke Lemur Center, Duke University, Durham, North Carolina, USA
| | - Kay H Welser
- Duke Lemur Center, Duke University, Durham, North Carolina, USA
| | - Erin E Ehmke
- Duke Lemur Center, Duke University, Durham, North Carolina, USA
| | - Anne D Yoder
- Department of Biology, Duke University, Durham, North Carolina, USA
| | - Peter H Klopfer
- Department of Biology, Duke University, Durham, North Carolina, USA
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2
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Heckley AM, Harding CD, Page RA, Klein BA, Yovel Y, Diebold CA, Tilley HB. The effect of group size on sleep in a neotropical bat, Artibeus jamaicensis. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART A, ECOLOGICAL AND INTEGRATIVE PHYSIOLOGY 2024. [PMID: 39051138 DOI: 10.1002/jez.2860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Revised: 06/06/2024] [Accepted: 07/08/2024] [Indexed: 07/27/2024]
Abstract
Sleep is associated with many costs, but is also important to survival, with a lack of sleep impairing cognitive function and increasing mortality. Sleeping in groups could alleviate sleep-associated costs, or could introduce new costs if social sleeping disrupts sleep. Working with the Jamaican fruit bat (Artibeus jamaicensis), we aimed to: (1) describe sleep architecture, (2) assess how sleeping in groups affects sleep, and (3) quantify total sleep time and identify rapid eye movement (REM) sleep using behavioral indicators that complement physiological evidence of sleep. Twenty-five adult bats were captured in Panama and recorded sleeping in an artificial roost enclosure. Three bats were fitted with an electromyograph and accelerometer and video recorded sleeping alone in controlled laboratory settings. The remaining 22 bats were assigned to differing social configurations (alone, dyad, triad, and tetrad) and video recorded sleeping in an outdoor flight cage. We found that sleep was highly variable among individuals (ranging from 2 h 53 min to 9 h 39 min over a 12-h period). Although we did not detect statistically significant effects and our sample size was limited, preliminary trends suggest that male bats may sleep longer than females, and individuals sleeping in groups may sleep longer than individuals sleeping alone. We also found a high correspondence between total sleep time quantified visually and quantified using actigraphy (with a 2-min immobility threshold) and identified physiological correlates of behaviorally-defined REM. These results serve as a starting point for future work on the ecology and evolution of sleep in bats and other wild mammals.
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Affiliation(s)
- Alexis M Heckley
- Smithsonian Tropical Research Institute, Gamboa, Panama
- Department of Biology and Redpath Museum, McGill University, Quebec, Canada
| | - Christian D Harding
- Division of Pulmonary, Critical Care, Sleep Medicine & Physiology, University of California San Diego, San Diego, USA
| | - Rachel A Page
- Smithsonian Tropical Research Institute, Gamboa, Panama
| | - Barrett A Klein
- Department of Biology, University of Wisconsin-La Crosse, Wisconsin, USA
| | - Yossi Yovel
- School of Zoology, School of Neuroscience, Tel-Aviv University, Tel Aviv, Israel
| | - Clarice A Diebold
- Smithsonian Tropical Research Institute, Gamboa, Panama
- The Department of Physiological & Brain Sciences, Johns Hopkins University, Maryland, USA
| | - Hannah B Tilley
- Smithsonian Tropical Research Institute, Gamboa, Panama
- Division of Ecology and Biodiversity, School of Biological Sciences, University of Hong Kong, Hong Kong, Hong Kong
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3
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Metcalfe NB, Bellman J, Bize P, Blier PU, Crespel A, Dawson NJ, Dunn RE, Halsey LG, Hood WR, Hopkins M, Killen SS, McLennan D, Nadler LE, Nati JJH, Noakes MJ, Norin T, Ozanne SE, Peaker M, Pettersen AK, Przybylska-Piech A, Rathery A, Récapet C, Rodríguez E, Salin K, Stier A, Thoral E, Westerterp KR, Westerterp-Plantenga MS, Wojciechowski MS, Monaghan P. Solving the conundrum of intra-specific variation in metabolic rate: A multidisciplinary conceptual and methodological toolkit: New technical developments are opening the door to an understanding of why metabolic rate varies among individual animals of a species: New technical developments are opening the door to an understanding of why metabolic rate varies among individual animals of a species. Bioessays 2023; 45:e2300026. [PMID: 37042115 DOI: 10.1002/bies.202300026] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 03/24/2023] [Accepted: 03/27/2023] [Indexed: 04/13/2023]
Abstract
Researchers from diverse disciplines, including organismal and cellular physiology, sports science, human nutrition, evolution and ecology, have sought to understand the causes and consequences of the surprising variation in metabolic rate found among and within individual animals of the same species. Research in this area has been hampered by differences in approach, terminology and methodology, and the context in which measurements are made. Recent advances provide important opportunities to identify and address the key questions in the field. By bringing together researchers from different areas of biology and biomedicine, we describe and evaluate these developments and the insights they could yield, highlighting the need for more standardisation across disciplines. We conclude with a list of important questions that can now be addressed by developing a common conceptual and methodological toolkit for studies on metabolic variation in animals.
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Affiliation(s)
- Neil B Metcalfe
- School of Biodiversity, One Health & Veterinary Medicine, University of Glasgow, Glasgow, UK
| | - Jakob Bellman
- Department of Physiology, Institute of Neuroscience and Physiology, University of Gothenburg, Gothenburg, Sweden
| | - Pierre Bize
- Swiss Ornithological Institute, Sempach, Switzerland
| | - Pierre U Blier
- Département de Biologie, Université de Québec à Rimouski, Rimouski, Canada
| | - Amélie Crespel
- Department of Biology, University of Turku, Turku, Finland
| | - Neal J Dawson
- School of Biodiversity, One Health & Veterinary Medicine, University of Glasgow, Glasgow, UK
| | - Ruth E Dunn
- Lancaster Environment Centre, University of Lancaster, Lancaster, UK
| | - Lewis G Halsey
- School of Life and Health Sciences, University of Roehampton, London, UK
| | - Wendy R Hood
- Department of Biological Sciences, Auburn University, Auburn, USA
| | - Mark Hopkins
- School of Food Science and Nutrition, Leeds University, Leeds, UK
| | - Shaun S Killen
- School of Biodiversity, One Health & Veterinary Medicine, University of Glasgow, Glasgow, UK
| | - Darryl McLennan
- School of Biodiversity, One Health & Veterinary Medicine, University of Glasgow, Glasgow, UK
| | - Lauren E Nadler
- Ocean and Earth Science, NOC, University of Southampton, Southampton, UK
| | - Julie J H Nati
- Ocean Sciences Center, Memorial University of Newfoundland, St John's, Canada
| | - Matthew J Noakes
- School of Animal, Plant, and Environmental Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Tommy Norin
- DTU Aqua: National Institute of Aquatic Resources, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Susan E Ozanne
- Wellcome-MRC Institute of Metabolic Science, University of Cambridge, Cambridge, UK
| | | | - Amanda K Pettersen
- School of Biodiversity, One Health & Veterinary Medicine, University of Glasgow, Glasgow, UK
- School of Life & Environmental Sciences, The University of Sydney, Sydney, Australia
| | - Anna Przybylska-Piech
- Department of Vertebrate Zoology & Ecology, Nicolaus Copernicus University, Toruń, Poland
| | - Alann Rathery
- School of Life and Health Sciences, University of Roehampton, London, UK
| | - Charlotte Récapet
- Universite de Pau et des Pays de l'Adour, E2S UPPA, INRAE, ECOBIOP, Saint-Pée-sur-, Nivelle, France
| | - Enrique Rodríguez
- Department of Genetics, Evolution & Environment, University College London, London, UK
| | - Karine Salin
- IFREMER, Univ Brest, CNRS, IRD, Laboratory of Environmental Marine Sciences, Plouzané, France
| | - Antoine Stier
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, ENTPE, UMR 5023 LEHNA, Villeurbanne, France
| | - Elisa Thoral
- Department of Biology, Lund University, Lund, Sweden
| | - Klaas R Westerterp
- Department of Nutrition & Movement Sciences, Maastricht University, Maastricht, The Netherlands
| | | | - Michał S Wojciechowski
- Department of Vertebrate Zoology & Ecology, Nicolaus Copernicus University, Toruń, Poland
| | - Pat Monaghan
- School of Biodiversity, One Health & Veterinary Medicine, University of Glasgow, Glasgow, UK
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Role of Dorsomedial Hypothalamus GABAergic Neurons in Sleep-Wake States in Response to Changes in Ambient Temperature in Mice. Int J Mol Sci 2022; 23:ijms23031270. [PMID: 35163194 PMCID: PMC8836016 DOI: 10.3390/ijms23031270] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 01/19/2022] [Accepted: 01/19/2022] [Indexed: 02/06/2023] Open
Abstract
Good sleep quality is essential for maintaining the body's attention during wakefulness, which is easily affected by external factors such as an ambient temperature. However, the mechanism by which an ambient temperature influences sleep-wake behaviors remains unclear. The dorsomedial hypothalamus (DMH) has been reported to be involved in thermoregulation. It also receives projection from the preoptic area, which is an important region for sleep and energy homeostasis and the suprachiasmatic nucleus-a main control area of the clock rhythm. Therefore, we hypothesized that the DMH plays an important role in the regulation of sleep related to ambient temperatures. In this study, we found that cold exposure (24/20/16/12 °C) increased wakefulness and decreased non-rapid eye movement (NREM) sleep, while warm exposure (32/36/40/44 °C) increased NREM sleep and decreased wakefulness compared to 28 °C conditions in wild-type mice. Then, using non-specific and specific apoptosis, we found that lesions of whole DMH neurons and DMH γ-aminobutyric acid (GABA)-ergic neurons induced by caspase-3 virus aggravated the fluctuation of core body temperature after warm exposure and attenuated the change in sleep-wake behaviors during cold and warm exposure. However, chemogenetic activation or inhibition of DMH GABAergic neurons did not affect the sleep-wake cycle. Collectively, our findings reveal an essential role of DMH GABAergic neurons in the regulation of sleep-wake behaviors elicited by a change in ambient temperature.
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Cerri M, Amici R. Thermoregulation and Sleep: Functional Interaction and Central Nervous Control. Compr Physiol 2021; 11:1591-1604. [PMID: 33792906 DOI: 10.1002/cphy.c140012] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Each of the wake-sleep states is characterized by specific changes in autonomic activity and bodily functions. The goal of such changes is not always clear. During non-rapid eye movement (NREM) sleep, the autonomic outflow and the activity of the endocrine system, the respiratory system, the cardiovascular system, and the thermoregulatory system seem to be directed at increasing energy saving. During rapid eye movement (REM) sleep, the goal of the specific autonomic and regulatory changes is unclear, since a large instability of autonomic activity and cardiorespiratory function is observed in concomitance with thermoregulatory changes, which are apparently non-functional to thermal homeostasis. Reciprocally, the activation of thermoregulatory responses under thermal challenges interferes with sleep occurrence. Such a double-edged and reciprocal interaction between sleep and thermoregulation may be favored by the fact that the central network controlling sleep overlaps in several parts with the central network controlling thermoregulation. The understanding of the central mechanism behind the interaction between sleep and thermoregulation may help to understand the functionality of thermoregulatory sleep-related changes and, ultimately, the function(s) of sleep. © 2021 American Physiological Society. Compr Physiol 11:1591-1604, 2021.
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Affiliation(s)
- Matteo Cerri
- Department of Biomedical and Neuromotor Sciences - Physiology, Alma Mater Studiorum - University of Bologna, Bologna, Italy
| | - Roberto Amici
- Department of Biomedical and Neuromotor Sciences - Physiology, Alma Mater Studiorum - University of Bologna, Bologna, Italy
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Blanco MB, Greene LK, Schopler R, Williams CV, Lynch D, Browning J, Welser K, Simmons M, Klopfer PH, Ehmke EE. On the modulation and maintenance of hibernation in captive dwarf lemurs. Sci Rep 2021; 11:5740. [PMID: 33707506 PMCID: PMC7952597 DOI: 10.1038/s41598-021-84727-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 02/18/2021] [Indexed: 11/09/2022] Open
Abstract
In nature, photoperiod signals environmental seasonality and is a strong selective "zeitgeber" that synchronizes biological rhythms. For animals facing seasonal environmental challenges and energetic bottlenecks, daily torpor and hibernation are two metabolic strategies that can save energy. In the wild, the dwarf lemurs of Madagascar are obligate hibernators, hibernating between 3 and 7 months a year. In captivity, however, dwarf lemurs generally express torpor for periods far shorter than the hibernation season in Madagascar. We investigated whether fat-tailed dwarf lemurs (Cheirogaleus medius) housed at the Duke Lemur Center (DLC) could hibernate, by subjecting 8 individuals to husbandry conditions more in accord with those in Madagascar, including alternating photoperiods, low ambient temperatures, and food restriction. All dwarf lemurs displayed daily and multiday torpor bouts, including bouts lasting ~ 11 days. Ambient temperature was the greatest predictor of torpor bout duration, and food ingestion and night length also played a role. Unlike their wild counterparts, who rarely leave their hibernacula and do not feed during hibernation, DLC dwarf lemurs sporadically moved and ate. While demonstrating that captive dwarf lemurs are physiologically capable of hibernation, we argue that facilitating their hibernation serves both husbandry and research goals: first, it enables lemurs to express the biphasic phenotypes (fattening and fat depletion) that are characteristic of their wild conspecifics; second, by "renaturalizing" dwarf lemurs in captivity, they will emerge a better model for understanding both metabolic extremes in primates generally and metabolic disorders in humans specifically.
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Affiliation(s)
- Marina B Blanco
- Duke Lemur Center, Durham, NC, 27705, USA. .,Department of Biology, Duke University, Durham, NC, 27708, USA.
| | - Lydia K Greene
- Duke Lemur Center, Durham, NC, 27705, USA.,Department of Biology, Duke University, Durham, NC, 27708, USA
| | | | | | | | | | - Kay Welser
- Duke Lemur Center, Durham, NC, 27705, USA
| | | | - Peter H Klopfer
- Department of Biology, Duke University, Durham, NC, 27708, USA
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7
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Shi Z, Qin M, Huang L, Xu T, Chen Y, Hu Q, Peng S, Peng Z, Qu LN, Chen SG, Tuo QH, Liao DF, Wang XP, Wu RR, Yuan TF, Li YH, Liu XM. Human torpor: translating insights from nature into manned deep space expedition. Biol Rev Camb Philos Soc 2020; 96:642-672. [PMID: 33314677 DOI: 10.1111/brv.12671] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 11/09/2020] [Accepted: 11/17/2020] [Indexed: 12/12/2022]
Abstract
During a long-duration manned spaceflight mission, such as flying to Mars and beyond, all crew members will spend a long period in an independent spacecraft with closed-loop bioregenerative life-support systems. Saving resources and reducing medical risks, particularly in mental heath, are key technology gaps hampering human expedition into deep space. In the 1960s, several scientists proposed that an induced state of suppressed metabolism in humans, which mimics 'hibernation', could be an ideal solution to cope with many issues during spaceflight. In recent years, with the introduction of specific methods, it is becoming more feasible to induce an artificial hibernation-like state (synthetic torpor) in non-hibernating species. Natural torpor is a fascinating, yet enigmatic, physiological process in which metabolic rate (MR), body core temperature (Tb ) and behavioural activity are reduced to save energy during harsh seasonal conditions. It employs a complex central neural network to orchestrate a homeostatic state of hypometabolism, hypothermia and hypoactivity in response to environmental challenges. The anatomical and functional connections within the central nervous system (CNS) lie at the heart of controlling synthetic torpor. Although progress has been made, the precise mechanisms underlying the active regulation of the torpor-arousal transition, and their profound influence on neural function and behaviour, which are critical concerns for safe and reversible human torpor, remain poorly understood. In this review, we place particular emphasis on elaborating the central nervous mechanism orchestrating the torpor-arousal transition in both non-flying hibernating mammals and non-hibernating species, and aim to provide translational insights into long-duration manned spaceflight. In addition, identifying difficulties and challenges ahead will underscore important concerns in engineering synthetic torpor in humans. We believe that synthetic torpor may not be the only option for manned long-duration spaceflight, but it is the most achievable solution in the foreseeable future. Translating the available knowledge from natural torpor research will not only benefit manned spaceflight, but also many clinical settings attempting to manipulate energy metabolism and neurobehavioural functions.
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Affiliation(s)
- Zhe Shi
- National Clinical Research Center for Mental Disorders, and Department of Psychaitry, The Second Xiangya Hospital of Central South University, Changsha, Hunan, 410011, China.,Key Laboratory for Quality Evaluation of Bulk Herbs of Hunan Province, Hunan University of Chinese Medicine, Changsha, Hunan, 410208, China.,State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, 100094, China.,Shanghai Key Laboratory of Psychotic Disorders, Shanghai Mental Health Center, Shanghai Jiaotong University School of Medicine, Shanghai, 200030, China
| | - Meng Qin
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, 100029, China
| | - Lu Huang
- Guangdong-Hongkong-Macau Institute of CNS Regeneration, Ministry of Education CNS Regeneration Collaborative Joint Laboratory, Jinan University, Guangzhou, 510632, China
| | - Tao Xu
- Department of Anesthesiology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, 200233, China
| | - Ying Chen
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700, China
| | - Qin Hu
- College of Life Sciences and Bio-Engineering, Beijing University of Technology, Beijing, 100024, China
| | - Sha Peng
- Key Laboratory for Quality Evaluation of Bulk Herbs of Hunan Province, Hunan University of Chinese Medicine, Changsha, Hunan, 410208, China
| | - Zhuang Peng
- Key Laboratory for Quality Evaluation of Bulk Herbs of Hunan Province, Hunan University of Chinese Medicine, Changsha, Hunan, 410208, China
| | - Li-Na Qu
- State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, 100094, China
| | - Shan-Guang Chen
- State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, 100094, China
| | - Qin-Hui Tuo
- Key Laboratory for Quality Evaluation of Bulk Herbs of Hunan Province, Hunan University of Chinese Medicine, Changsha, Hunan, 410208, China
| | - Duan-Fang Liao
- Key Laboratory for Quality Evaluation of Bulk Herbs of Hunan Province, Hunan University of Chinese Medicine, Changsha, Hunan, 410208, China
| | - Xiao-Ping Wang
- National Clinical Research Center for Mental Disorders, and Department of Psychaitry, The Second Xiangya Hospital of Central South University, Changsha, Hunan, 410011, China
| | - Ren-Rong Wu
- National Clinical Research Center for Mental Disorders, and Department of Psychaitry, The Second Xiangya Hospital of Central South University, Changsha, Hunan, 410011, China
| | - Ti-Fei Yuan
- Shanghai Key Laboratory of Psychotic Disorders, Shanghai Mental Health Center, Shanghai Jiaotong University School of Medicine, Shanghai, 200030, China.,Co-innovation Center of Neuroregeneration, Nantong University, Nantong, 226000, China
| | - Ying-Hui Li
- State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, 100094, China
| | - Xin-Min Liu
- Key Laboratory for Quality Evaluation of Bulk Herbs of Hunan Province, Hunan University of Chinese Medicine, Changsha, Hunan, 410208, China.,State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, 100094, China.,Research Center for Pharmacology and Toxicology, Institute of Medicinal Plant Development (IMPLAD), Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100193, China
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8
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Mohr SM, Bagriantsev SN, Gracheva EO. Cellular, Molecular, and Physiological Adaptations of Hibernation: The Solution to Environmental Challenges. Annu Rev Cell Dev Biol 2020; 36:315-338. [PMID: 32897760 DOI: 10.1146/annurev-cellbio-012820-095945] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Thriving in times of resource scarcity requires an incredible flexibility of behavioral, physiological, cellular, and molecular functions that must change within a relatively short time. Hibernation is a collection of physiological strategies that allows animals to inhabit inhospitable environments, where they experience extreme thermal challenges and scarcity of food and water. Many different kinds of animals employ hibernation, and there is a spectrum of hibernation phenotypes. Here, we focus on obligatory mammalian hibernators to identify the unique challenges they face and the adaptations that allow hibernators to overcome them. This includes the cellular and molecular strategies used to combat low environmental and body temperatures and lack of food and water. We discuss metabolic, neuronal, and hormonal cues that regulate hibernation and how they are thought to be coordinated by internal clocks. Last, we touch on questions that are left to be addressed in the field of hibernation research. Studies from the last century and more recent work reveal that hibernation is not simply a passive reduction in body temperature and vital parameters but rather an active process seasonally regulated at the molecular, cellular, and organismal levels.
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Affiliation(s)
- Sarah M Mohr
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06510, USA; .,Department of Neuroscience and Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, Connecticut 06510, USA;
| | - Sviatoslav N Bagriantsev
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06510, USA;
| | - Elena O Gracheva
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06510, USA; .,Department of Neuroscience and Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, Connecticut 06510, USA;
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9
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Nowack J, Levesque DL, Reher S, Dausmann KH. Variable Climates Lead to Varying Phenotypes: “Weird” Mammalian Torpor and Lessons From Non-Holarctic Species. Front Ecol Evol 2020. [DOI: 10.3389/fevo.2020.00060] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
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10
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Royo J, Aujard F, Pifferi F. Daily Torpor and Sleep in a Non-human Primate, the Gray Mouse Lemur ( Microcebus murinus). Front Neuroanat 2019; 13:87. [PMID: 31616258 PMCID: PMC6768945 DOI: 10.3389/fnana.2019.00087] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 09/11/2019] [Indexed: 11/16/2022] Open
Abstract
Daily torpor is an energy-saving process that evolved as an extension of non-rapid eye movement (NREM) sleep mechanisms. In many heterothermic species there is a relation between torpor expression and the repartition of the different behavioral states of sleep. Despite the presence of sleep during this period of hypothermia, torpor induces an accumulation of sleep debt which results in a rebound of sleep in mammals. We aimed to investigate the expression of sleep-wake rhythms and delta waves during daily torpor at various ambient temperatures in a non-human primate model, the gray mouse lemur (Microcebus murinus). Cortical activity was measured with telemetric electroencephalography (EEG) recordings in the prefrontal cortex (PFC) during the torpor episode and the next 24 h following hypothermia. Gray mouse lemurs were divided into two groups: the first group was subjected to normal ambient temperatures (25°C) whereas the second group was placed at lower ambient temperatures (10°C). Contrary to normal ambient temperatures, sleep-wake rhythms were maintained during torpor until body temperature (Tb) of the animals reached 21°C. Below this temperature, NREM and REM sleep strongly decreased or were absent whereas the EEG became isoelectric. The different states of sleep were proportional to Tbmin during prior torpor in contrast to active phases. Delta waves increased after torpor but low Tb did not induce greater delta power compared to higher temperatures. Our results showed that Tb was a determining factor for the quality and quantity of sleep. Low Tb might be inconsistent with the recovery function of sleep. Heterothermy caused a sleep debt thus there was a rebound of sleep at the beginning of euthermia to compensate for the lack of sleep.
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Affiliation(s)
- Julie Royo
- UMR CNRS MNHN 7179 MECADEV, BioAdapt Team, Brunoy, France
| | | | - Fabien Pifferi
- UMR CNRS MNHN 7179 MECADEV, BioAdapt Team, Brunoy, France
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11
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Harding EC, Franks NP, Wisden W. The Temperature Dependence of Sleep. Front Neurosci 2019; 13:336. [PMID: 31105512 PMCID: PMC6491889 DOI: 10.3389/fnins.2019.00336] [Citation(s) in RCA: 84] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 03/22/2019] [Indexed: 12/18/2022] Open
Abstract
Mammals have evolved a range of behavioural and neurological mechanisms that coordinate cycles of thermoregulation and sleep. Whether diurnal or nocturnal, sleep onset and a reduction in core temperature occur together. Non-rapid eye movement (NREM) sleep episodes are also accompanied by core and brain cooling. Thermoregulatory behaviours, like nest building and curling up, accompany this circadian temperature decline in preparation for sleeping. This could be a matter of simply comfort as animals seek warmth to compensate for lower temperatures. However, in both humans and other mammals, direct skin warming can shorten sleep-latency and promote NREM sleep. We discuss the evidence that body cooling and sleep are more fundamentally connected and that thermoregulatory behaviours, prior to sleep, form warm microclimates that accelerate NREM directly through neuronal circuits. Paradoxically, this warmth might also induce vasodilation and body cooling. In this way, warmth seeking and nesting behaviour might enhance the circadian cycle by activating specific circuits that link NREM initiation to body cooling. We suggest that these circuits explain why NREM onset is most likely when core temperature is at its steepest rate of decline and why transitions to NREM are accompanied by a decrease in brain temperature. This connection may have implications for energy homeostasis and the function of sleep.
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Affiliation(s)
- Edward C Harding
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Nicholas P Franks
- Department of Life Sciences, Imperial College London, London, United Kingdom.,Centre for Neurotechnology, Imperial College London, London, United Kingdom.,UK Dementia Research Institute, Imperial College London, London, United Kingdom
| | - William Wisden
- Department of Life Sciences, Imperial College London, London, United Kingdom.,Centre for Neurotechnology, Imperial College London, London, United Kingdom.,UK Dementia Research Institute, Imperial College London, London, United Kingdom
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12
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Blanco MB, Dausmann KH, Faherty SL, Yoder AD. Tropical heterothermy is “cool”: The expression of daily torpor and hibernation in primates. Evol Anthropol 2018; 27:147-161. [DOI: 10.1002/evan.21588] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2018] [Accepted: 03/15/2018] [Indexed: 12/19/2022]
Affiliation(s)
| | | | | | - Anne D. Yoder
- Duke Lemur Center; Durham North Carolina
- Department of Biology; Duke University; Durham North Carolina
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13
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Griko YV, Rask JC, Raychev R. Advantage of Animal Models with Metabolic Flexibility for Space Research Beyond Low Earth Orbit. ACTA ACUST UNITED AC 2017. [DOI: 10.1089/space.2016.0024] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Yuri V. Griko
- Space Biosciences Division, NASA-Ames Research Center, Moffett Field, California
| | - Jon C. Rask
- Space Biosciences Division, NASA-Ames Research Center, Moffett Field, California
- KBRwyle, Moffett Field, California
| | - Raycho Raychev
- Space Challenges Program, EnduroSat, Inc., Sofia, Bulgaria
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14
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Cerri M, Luppi M, Tupone D, Zamboni G, Amici R. REM Sleep and Endothermy: Potential Sites and Mechanism of a Reciprocal Interference. Front Physiol 2017; 8:624. [PMID: 28883799 PMCID: PMC5573803 DOI: 10.3389/fphys.2017.00624] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Accepted: 08/11/2017] [Indexed: 01/11/2023] Open
Abstract
Numerous data show a reciprocal interaction between REM sleep and thermoregulation. During REM sleep, the function of thermoregulation appears to be impaired; from the other hand, the tonic activation of thermogenesis, such as during cold exposure, suppresses REM sleep occurrence. Recently, both the central neural network controlling REM sleep and the central neural network controlling thermoregulation have been progressively unraveled. Thermoregulation was shown to be controlled by a central “core” circuit, responsible for the maintenance of body temperature, modulated by a set of accessory areas. REM sleep was suggested to be controlled by a group of hypothalamic neurons overlooking at the REM sleep generating circuits within the brainstem. The two networks overlap in a few areas, and in this review, we will suggest that in such overlap may reside the explanation of the reciprocal interaction between REM sleep and thermoregulation. Considering the peculiar modulation of thermoregulation by REM sleep the result of their coincidental evolution, REM sleep may therefore be seen as a period of transient heterothermy.
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Affiliation(s)
- Matteo Cerri
- Department of Biomedical and NeuroMotor Sciences, University of BolognaBologna, Italy
| | - Marco Luppi
- Department of Biomedical and NeuroMotor Sciences, University of BolognaBologna, Italy
| | - Domenico Tupone
- Department of Biomedical and NeuroMotor Sciences, University of BolognaBologna, Italy
| | - Giovanni Zamboni
- Department of Biomedical and NeuroMotor Sciences, University of BolognaBologna, Italy
| | - Roberto Amici
- Department of Biomedical and NeuroMotor Sciences, University of BolognaBologna, Italy
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15
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Tarahovsky YS, Fadeeva IS, Komelina NP, Khrenov MO, Zakharova NM. Antipsychotic inductors of brain hypothermia and torpor-like states: perspectives of application. Psychopharmacology (Berl) 2017; 234:173-184. [PMID: 27933367 DOI: 10.1007/s00213-016-4496-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Accepted: 11/26/2016] [Indexed: 12/12/2022]
Abstract
Hypothermia and hypometabolism (hypometabothermia) normally observed during natural hibernation and torpor, allow animals to protect their body and brain against the damaging effects of adverse environment. A similar state of hypothermia can be achieved under artificial conditions through physical cooling or pharmacological effects directed at suppression of metabolism and the processes of thermoregulation. In these conditions called torpor-like states, the mammalian ability to recover from stroke, heart attack, and traumatic injuries greatly increases. Therefore, the development of therapeutic methods for different pathologies is a matter of great concern. With the discovery of the antipsychotic drug chlorpromazine in the 1950s of the last century, the first attempts to create a pharmacologically induced state of hibernation for therapeutic purposes were made. That was the beginning of numerous studies in animals and the broad use of therapeutic hypothermia in medicine. Over the last years, many new agents have been discovered which were capable of lowering the body temperature and inhibiting the metabolism. The psychotropic agents occupy a significant place among them, which, in our opinion, is not sufficiently recognized in the contemporary literature. In this review, we summarized the latest achievements related to the ability of modern antipsychotics to target specific receptors in the brain, responsible for the initiation of hypometabothermia.
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Affiliation(s)
- Yury S Tarahovsky
- Institute of Cell Biophysics RAS, Pushchino, Moscow Region, Russian Federation, 142290. .,Institute of Theoretical and Experimental Biophysics RAS, Pushchino, Moscow Region, Russian Federation, 142290.
| | - Irina S Fadeeva
- Institute of Cell Biophysics RAS, Pushchino, Moscow Region, Russian Federation, 142290.,Institute of Theoretical and Experimental Biophysics RAS, Pushchino, Moscow Region, Russian Federation, 142290
| | - Natalia P Komelina
- Institute of Cell Biophysics RAS, Pushchino, Moscow Region, Russian Federation, 142290
| | - Maxim O Khrenov
- Institute of Cell Biophysics RAS, Pushchino, Moscow Region, Russian Federation, 142290
| | - Nadezhda M Zakharova
- Institute of Cell Biophysics RAS, Pushchino, Moscow Region, Russian Federation, 142290
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16
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Faherty SL, Villanueva-Cañas JL, Klopfer PH, Albà MM, Yoder AD. Gene Expression Profiling in the Hibernating Primate, Cheirogaleus Medius. Genome Biol Evol 2016; 8:2413-26. [PMID: 27412611 PMCID: PMC5010898 DOI: 10.1093/gbe/evw163] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/01/2016] [Indexed: 12/24/2022] Open
Abstract
Hibernation is a complex physiological response that some mammalian species employ to evade energetic demands. Previous work in mammalian hibernators suggests that hibernation is activated not by a set of genes unique to hibernators, but by differential expression of genes that are present in all mammals. This question of universal genetic mechanisms requires further investigation and can only be tested through additional investigations of phylogenetically dispersed species. To explore this question, we use RNA-Seq to investigate gene expression dynamics as they relate to the varying physiological states experienced throughout the year in a group of primate hibernators-Madagascar's dwarf lemurs (genus Cheirogaleus). In a novel experimental approach, we use longitudinal sampling of biological tissues as a method for capturing gene expression profiles from the same individuals throughout their annual hibernation cycle. We identify 90 candidate genes that have variable expression patterns when comparing two active states (Active 1 and Active 2) with a torpor state. These include genes that are involved in metabolic pathways, feeding behavior, and circadian rhythms, as might be expected to correlate with seasonal physiological state changes. The identified genes appear to be critical for maintaining the health of an animal that undergoes prolonged periods of metabolic depression concurrent with the hibernation phenotype. By focusing on these differentially expressed genes in dwarf lemurs, we compare gene expression patterns in previously studied mammalian hibernators. Additionally, by employing evolutionary rate analysis, we find that hibernation-related genes do not evolve under positive selection in hibernating species relative to nonhibernators.
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Affiliation(s)
| | - José Luis Villanueva-Cañas
- Evolutionary Genomics Group, Research Programme on Biomedical Informatics (GRIB), Hospital del Mar Research Institute (IMIM), Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | | | - M Mar Albà
- Evolutionary Genomics Group, Research Programme on Biomedical Informatics (GRIB), Hospital del Mar Research Institute (IMIM), Universitat Pompeu Fabra (UPF), Barcelona, Spain Catalan Institution for Research and Advanced Studies (ICREA), Barcelona, Spain
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17
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Blanco MB, Dausmann KH, Faherty SL, Klopfer P, Krystal AD, Schopler R, Yoder AD. Hibernation in a primate: does sleep occur? ROYAL SOCIETY OPEN SCIENCE 2016; 3:160282. [PMID: 27853604 PMCID: PMC5108954 DOI: 10.1098/rsos.160282] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Accepted: 07/05/2016] [Indexed: 06/06/2023]
Abstract
During hibernation, critical physiological processes are downregulated and thermogenically induced arousals are presumably needed periodically to fulfil those physiological demands. Among the processes incompatible with a hypome tabolic state is sleep. However, one hibernating primate, the dwarf lemur Cheirogaleus medius, experiences rapid eye movement (REM)-like states during hibernation, whenever passively reaching temperatures above 30°C, as occurs when it hibernates in poorly insulated tree hollows under tropical conditions. Here, we report electroencephalographic (EEG) recordings, temperature data and metabolic rates from two related species (C. crossleyi and C. sibreei), inhabiting high-altitude rainforests and hibernating underground, conditions that mirror, to some extent, those experienced by temperate hibernators. We compared the physiology of hibernation and spontaneous arousals in these animals to C. medius, as well as the much more distantly related non-primate hibernators, such as Arctic, golden-mantled and European ground squirrels. We observed a number of commonalities with non-primate temperate hibernators including: (i) monotonous ultra-low voltage EEG during torpor bouts in these relatively cold-weather hibernators, (ii) the absence of sleep during torpor bouts, (iii) the occurrence of spontaneous arousals out of torpor, during which sleep regularly occurred, (iv) relatively high early EEG non-REM during the arousal, and (v) a gradual transition to the torpid EEG state from non-REM sleep. Unlike C. medius, our study species did not display sleep-like states during torpor bouts, but instead exclusively exhibited them during arousals. During these short euthermic periods, non-REM as well as REM sleep-like stages were observed. Differences observed between these two species and their close relative, C. medius, for which data have been published, presumably reflect differences in hibernaculum temperature.
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Affiliation(s)
| | | | | | - Peter Klopfer
- Department of Biology, Duke University, Durham, NC, USA
| | - Andrew D. Krystal
- Department of Psychiatry and Behavioral Sciences, Duke University School of Medicine, Durham, NC, USA
| | | | - Anne D. Yoder
- Duke Lemur Center, 3705 Erwin Road, Durham, NC 27705, USA
- Department of Biology, Duke University, Durham, NC, USA
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18
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The energy allocation function of sleep: A unifying theory of sleep, torpor, and continuous wakefulness. Neurosci Biobehav Rev 2014; 47:122-53. [DOI: 10.1016/j.neubiorev.2014.08.001] [Citation(s) in RCA: 163] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 06/27/2014] [Accepted: 08/02/2014] [Indexed: 12/14/2022]
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Affiliation(s)
- K. H. Dausmann
- Department of Animal Ecology and Conservation, Biocentre Grindel; University of Hamburg; Hamburg Germany
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