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Hitrec T, Squarcio F, Piscitiello E, Cerri M, Martelli D, Occhinegro A, Taddei L, Tupone D, Amici R, Luppi M. Sleep deprivation soon after recovery from synthetic torpor enhances tau protein dephosphorylation in the rat brain. J Comp Physiol B 2024; 194:347-368. [PMID: 37812305 DOI: 10.1007/s00360-023-01516-2] [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: 05/15/2023] [Revised: 08/11/2023] [Accepted: 09/11/2023] [Indexed: 10/10/2023]
Abstract
Neuronal Tau protein hyperphosphorylation (PPtau) is a hallmark of tauopathic neurodegeneration. However, a reversible brain PPtau occurs in mammals during either natural or "synthetic" torpor (ST), a transient deep hypothermic state that can be pharmacologically induced in rats. Since in both conditions a high sleep pressure builds up during the regaining of euthermia, the aim of this work was to assess the possible role of post-ST sleep in PPtau dephosphorylation. Male rats were studied at the hypothermic nadir of ST, and 3-6 h after the recovery of euthermia, after either normal sleep (NS) or total sleep deprivation (SD). The effects of SD were studied by assessing: (i) deep brain temperature (Tb); (ii) immunofluorescent staining for AT8 (phosphorylated Tau) and Tau-1 (non-phosphorylated Tau), assessed in 19 brain structures; (iii) different phosphorylated forms of Tau and the main cellular factors involved in Tau phospho-regulation, including pro- and anti-apoptotic markers, assessed through western blot in the parietal cortex and hippocampus; (iv) systemic factors which are involved in natural torpor; (v) microglia activation state, by considering morphometric variations. Unexpectedly, the reversibility of PPtau was more efficient in SD than in NS animals, and was concomitant with a higher Tb, higher melatonin plasma levels, and a higher frequency of the microglia resting phenotype. Since the reversibility of ST-induced PPtau was previously shown to be driven by a latent physiological molecular mechanism triggered by deep hypothermia, short-term SD soon after the regaining of euthermia seems to boost the possible neuroprotective effects of this mechanism.
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Affiliation(s)
- Timna Hitrec
- Department of Biomedical and NeuroMotor Sciences, University of Bologna, Piazza di Porta San Donato, 2, 40126, Bologna, Italy
| | - Fabio Squarcio
- Department of Biomedical and NeuroMotor Sciences, University of Bologna, Piazza di Porta San Donato, 2, 40126, Bologna, Italy
- Department of Psychiatry, University of Wisconsin-Madison, Madison, WI, USA
| | - Emiliana Piscitiello
- Department of Biomedical and NeuroMotor Sciences, University of Bologna, Piazza di Porta San Donato, 2, 40126, Bologna, Italy
- Centre for Applied Biomedical Research - CRBA, University of Bologna, St. Orsola Hospital, Bologna, Italy
| | - Matteo Cerri
- Department of Biomedical and NeuroMotor Sciences, University of Bologna, Piazza di Porta San Donato, 2, 40126, Bologna, Italy
| | - Davide Martelli
- Department of Biomedical and NeuroMotor Sciences, University of Bologna, Piazza di Porta San Donato, 2, 40126, Bologna, Italy
- Centre for Applied Biomedical Research - CRBA, University of Bologna, St. Orsola Hospital, Bologna, Italy
| | - Alessandra Occhinegro
- Department of Biomedical and NeuroMotor Sciences, University of Bologna, Piazza di Porta San Donato, 2, 40126, Bologna, Italy
- Centre for Applied Biomedical Research - CRBA, University of Bologna, St. Orsola Hospital, Bologna, Italy
| | - Ludovico Taddei
- Department of Biomedical and NeuroMotor Sciences, University of Bologna, Piazza di Porta San Donato, 2, 40126, Bologna, Italy
- Centre for Applied Biomedical Research - CRBA, University of Bologna, St. Orsola Hospital, Bologna, Italy
| | - Domenico Tupone
- Department of Biomedical and NeuroMotor Sciences, University of Bologna, Piazza di Porta San Donato, 2, 40126, Bologna, Italy
- Department of Neurological Surgery, Oregon Health and Science University, Portland, OR, USA
| | - Roberto Amici
- Department of Biomedical and NeuroMotor Sciences, University of Bologna, Piazza di Porta San Donato, 2, 40126, Bologna, Italy
| | - Marco Luppi
- Department of Biomedical and NeuroMotor Sciences, University of Bologna, Piazza di Porta San Donato, 2, 40126, Bologna, Italy.
- Centre for Applied Biomedical Research - CRBA, University of Bologna, St. Orsola Hospital, Bologna, Italy.
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Diedrich V, Haugg E, Van Hee J, Herwig A. Role of glucose in daily torpor of Djungarian hamsters ( Phodopus sungorus): challenge of continuous in vivo blood glucose measurements. Am J Physiol Regul Integr Comp Physiol 2023; 325:R359-R379. [PMID: 37519255 DOI: 10.1152/ajpregu.00040.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 07/03/2023] [Accepted: 07/23/2023] [Indexed: 08/01/2023]
Abstract
Djungarian hamsters use daily torpor to save energy during winter. This metabolic downstate is part of their acclimatization strategy in response to short photoperiod and expressed spontaneously without energy challenges. During acute energy shortage, torpor incidence, depth, and duration can be modulated. Torpor induction might rely on glucose availability as acute metabolic energy source. To investigate this, the present study provides the first continuous in vivo blood glucose measurements of spontaneous daily torpor in short photoperiod-acclimated and fasting-induced torpor in long photoperiod-acclimated Djungarian hamsters. Glucose levels were almost identical in both photoperiods and showed a decrease during resting phase. Further decreases appeared during spontaneous daily torpor entrance, parallel with metabolic rate but before body temperature, while respiratory exchange rates were rising. During arousal, blood glucose tended to increase, and pretorpor values were reached at torpor termination. Although food-restricted hamsters underwent a considerable energetic challenge, blood glucose levels remained stable during the resting phase regardless of torpor expression. The activity phase preceding a torpor bout did not reveal changes in blood glucose that might be used as torpor predictor. Djungarian hamsters show a robust, circadian rhythm in blood glucose irrespective of season and maintain appropriate levels throughout complex acclimation processes including metabolic downstates. Although these measurements could not reveal blood glucose as proximate torpor induction factor, they provide new information about glucose availability during torpor. Technical innovations like in vivo microdialysis and in vitro transcriptome or proteome analyses may help to uncover the connection between torpor expression and glucose metabolism.
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Affiliation(s)
| | - Elena Haugg
- Institute of Neurobiology, Ulm University, Ulm, Germany
| | - Justin Van Hee
- Data Sciences International, St. Paul, Minnesota, United States
| | - Annika Herwig
- Institute of Neurobiology, Ulm University, Ulm, Germany
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3
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Scott KA, Tan Y, Johnson DN, Elsaafien K, Baumer-Harrison C, Eikenberry SA, Sa JM, de Lartigue G, de Kloet AD, Krause EG. Mechanosensation of the heart and gut elicits hypometabolism and vigilance in mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.29.547073. [PMID: 37425814 PMCID: PMC10327188 DOI: 10.1101/2023.06.29.547073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/11/2023]
Abstract
Interoception broadly refers to awareness of one's internal milieu. Vagal sensory afferents monitor the internal milieu and maintain homeostasis by engaging brain circuits that alter physiology and behavior. While the importance of the body-to-brain communication that underlies interoception is implicit, the vagal afferents and corresponding brain circuits that shape perception of the viscera are largely unknown. Here, we use mice to parse neural circuits subserving interoception of the heart and gut. We determine vagal sensory afferents expressing the oxytocin receptor, hereafter referred to as NDGOxtr, send projections to the aortic arch or stomach and duodenum with molecular and structural features indicative of mechanosensation. Chemogenetic excitation of NDGOxtr significantly decreases food and water consumption, and remarkably, produces a torpor-like phenotype characterized by reductions in cardiac output, body temperature, and energy expenditure. Chemogenetic excitation of NDGOxtr also creates patterns of brain activity associated with augmented hypothalamic-pituitary-adrenal axis activity and behavioral indices of vigilance. Recurrent excitation of NDGOxtr suppresses food intake and lowers body mass, indicating that mechanosensation of the heart and gut can exert enduring effects on energy balance. These findings suggest that the sensation of vascular stretch and gastrointestinal distention may have profound effects on whole body metabolism and mental health.
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Affiliation(s)
- Karen A. Scott
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, FL 32611, USA
- Center for Integrative Cardiovascular and Metabolic Diseases, University of Florida, Gainesville, FL 32611, USA
| | - Yalun Tan
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, FL 32611, USA
- Center for Integrative Cardiovascular and Metabolic Diseases, University of Florida, Gainesville, FL 32611, USA
| | - Dominique N. Johnson
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, FL 32611, USA
- Center for Integrative Cardiovascular and Metabolic Diseases, University of Florida, Gainesville, FL 32611, USA
| | - Khalid Elsaafien
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, FL 32611, USA
- Center for Integrative Cardiovascular and Metabolic Diseases, University of Florida, Gainesville, FL 32611, USA
| | - Caitlin Baumer-Harrison
- Department of Physiology and Functional Genomics, College of Medicine, University of Florida, Gainesville, FL 32611, USA
- Center for Integrative Cardiovascular and Metabolic Diseases, University of Florida, Gainesville, FL 32611, USA
| | - Sophia A. Eikenberry
- Department of Physiology and Functional Genomics, College of Medicine, University of Florida, Gainesville, FL 32611, USA
- Center for Integrative Cardiovascular and Metabolic Diseases, University of Florida, Gainesville, FL 32611, USA
| | - Jessica M. Sa
- Department of Physiology and Functional Genomics, College of Medicine, University of Florida, Gainesville, FL 32611, USA
- Center for Integrative Cardiovascular and Metabolic Diseases, University of Florida, Gainesville, FL 32611, USA
| | | | - Annette D. de Kloet
- Department of Physiology and Functional Genomics, College of Medicine, University of Florida, Gainesville, FL 32611, USA
- Center for Integrative Cardiovascular and Metabolic Diseases, University of Florida, Gainesville, FL 32611, USA
- McKnight Brain Institute, University of Florida, Gainesville, FL 32611, USA
| | - Eric G. Krause
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, FL 32611, USA
- Center for Integrative Cardiovascular and Metabolic Diseases, University of Florida, Gainesville, FL 32611, USA
- McKnight Brain Institute, University of Florida, Gainesville, FL 32611, USA
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Long A, Liu Y, Fang X, Jia L, Li Z, Hu J, Wu S, Chen C, Huang P, Wang Y. Famsin, a novel gut-secreted hormone, contributes to metabolic adaptations to fasting via binding to its receptor OLFR796. Cell Res 2023; 33:273-287. [PMID: 36806353 PMCID: PMC10066382 DOI: 10.1038/s41422-023-00782-7] [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: 08/30/2022] [Accepted: 01/19/2023] [Indexed: 02/19/2023] Open
Abstract
The intestine is responsible for nutrient absorption and orchestrates metabolism in different organs during feeding, a process which is partly controlled by intestine-derived hormones. However, it is unclear whether the intestine plays an important role in metabolism during fasting. Here we have identified a novel hormone, famsin, which is secreted from the intestine and promotes metabolic adaptations to fasting. Mechanistically, famsin is shed from a single-pass transmembrane protein, Gm11437, during fasting and then binds OLFR796, an olfactory receptor, to activate intracellular calcium mobilization. This famsin-OLFR796 signaling axis promotes gluconeogenesis and ketogenesis for energy mobilization, and torpor for energy conservation during fasting. In addition, neutralization of famsin by an antibody improves blood glucose profiles in diabetic models, which identifies famsin as a potential therapeutic target for treating diabetes. Therefore, our results demonstrate that communication between the intestine and other organs by a famsin-OLFR796 signaling axis is critical for metabolic adaptations to fasting.
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Affiliation(s)
- Aijun Long
- State Key Laboratory of Membrane Biology, MOE Key Laboratory of Bioinformatics, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Yang Liu
- State Key Laboratory of Membrane Biology, MOE Key Laboratory of Bioinformatics, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Xinlei Fang
- State Key Laboratory of Membrane Biology, MOE Key Laboratory of Bioinformatics, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Liangjie Jia
- State Key Laboratory of Membrane Biology, MOE Key Laboratory of Bioinformatics, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Zhiyuan Li
- State Key Laboratory of Membrane Biology, MOE Key Laboratory of Bioinformatics, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Jiang Hu
- The Second Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China
| | - Shuang Wu
- The Second Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China
| | - Chao Chen
- The First Clinical Medical College of Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China
| | - Ping Huang
- The Second Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou, Zhejiang, China.
| | - Yiguo Wang
- State Key Laboratory of Membrane Biology, MOE Key Laboratory of Bioinformatics, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China.
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5
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López JM, Carballeira P, Pozo J, León-Espinosa G, Muñoz A. Hypothalamic orexinergic neuron changes during the hibernation of the Syrian hamster. Front Neuroanat 2022; 16:993421. [PMID: 36157325 PMCID: PMC9501701 DOI: 10.3389/fnana.2022.993421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 08/09/2022] [Indexed: 11/23/2022] Open
Abstract
Hibernation in small mammals is a highly regulated process with periods of torpor involving drops in body temperature and metabolic rate, as well as a general decrease in neural activity, all of which proceed alongside complex brain adaptive changes that appear to protect the brain from extreme hypoxia and low temperatures. All these changes are rapidly reversed, with no apparent brain damage occurring, during the short periods of arousal, interspersed during torpor—characterized by transitory and partial rewarming and activity, including sleep activation, and feeding in some species. The orexins are neuropeptides synthesized in hypothalamic neurons that project to multiple brain regions and are known to participate in the regulation of a variety of processes including feeding behavior, the sleep-wake cycle, and autonomic functions such as brown adipose tissue thermogenesis. Using multiple immunohistochemical techniques and quantitative analysis, we have characterized the orexinergic system in the brain of the Syrian hamster—a facultative hibernator. Our results revealed that orexinergic neurons in this species consisted of a neuronal population restricted to the lateral hypothalamic area, whereas orexinergic fibers distribute throughout the rostrocaudal extent of the brain, particularly innervating catecholaminergic and serotonergic neuronal populations. We characterized the changes of orexinergic cells in the different phases of hibernation based on the intensity of immunostaining for the neuronal activity marker C-Fos and orexin A (OXA). During torpor, we found an increase in C-Fos immunostaining intensity in orexinergic neurons, accompanied by a decrease in OXA immunostaining. These changes were accompanied by a volume reduction and a fragmentation of the Golgi apparatus (GA) as well as a decrease in the colocalization of OXA and the GA marker GM-130. Importantly, during arousal, C-Fos and OXA expression in orexinergic neurons was highest and the structural appearance and the volume of the GA along with the colocalization of OXA/GM-130 reverted to euthermic levels. We discuss the involvement of orexinergic cells in the regulation of mammalian hibernation and, in particular, the possibility that the high activation of orexinergic cells during the arousal stage guides the rewarming as well as the feeding and sleep behaviors characteristic of this phase.
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Affiliation(s)
- Jesús M. López
- Departamento de Biología Celular, Universidad Complutense, Madrid, Spain
| | - Paula Carballeira
- Departamento de Biología Celular, Universidad Complutense, Madrid, Spain
| | - Javier Pozo
- Departamento de Biología Celular, Universidad Complutense, Madrid, Spain
| | - Gonzalo León-Espinosa
- Departamento de Química y Bioquímica, Facultad de Farmacia, Universidad San Pablo-Centro de Estudios Universitarios (CEU), Madrid, Spain
| | - Alberto Muñoz
- Departamento de Biología Celular, Universidad Complutense, Madrid, Spain
- Laboratorio Cajal de Circuitos Corticales, Centro de Tecnología Biomédica (CTB), Universidad Politécnica de Madrid, Madrid, Spain
- Instituto Cajal, Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
- *Correspondence: Alberto Muñoz,
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Wang Y, Song Y, Dai Y, Li X, Xie J, Luo J, Yang C, Fan P, Xiao G, Luo Y, Wang Y, Li Y, Cai X. The burst of electrophysiological signals in the suprachiasmatic nucleus of mouse during the arousal detected by microelectrode arrays. Front Bioeng Biotechnol 2022; 10:970726. [PMID: 36110317 PMCID: PMC9468547 DOI: 10.3389/fbioe.2022.970726] [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: 06/16/2022] [Accepted: 08/10/2022] [Indexed: 11/13/2022] Open
Abstract
The neural mechanisms of torpor have essential reference significance for medical methods and long-term manned space. Changes in electrophysiology of suprachiasmatic nucleus (SCN) conduce to revealing the neural mechanisms from the torpor to arousal. Due to the lower physiology state during the torpor, it is a challenge to detect neural activities in vivo on freely behaving mice. Here, we introduced a multichannel microelectrode array (MEA) for real-time detection of local field potential (LFP) and action potential (spike) in the SCN in induced torpor mice. Meanwhile, core body temperature and behaviors of mice were recorded for further analysis. Platinum nanoparticles (PtNPs) and Nafion membrane modified MEA has a lower impedance (16.58 ± 3.93 kΩ) and higher signal-to-noise ratio (S/N = 6.1). We found that from torpor to arousal, the proportion of theta frequency bands of LFPs increased, spike firing rates rapidly increased. These results could all be characteristic information of arousal, supported by the microscopic neural activity promoting arousal in mice. MEA displayed real-time dynamic changes of neuronal activities in the SCN, which was more helpful to analyze and understand neural mechanisms of torpor and arousal. Our study provided a factual basis for the neural state in SCN of induced non-hibernating animals, which was helpful for the application of clinics and spaceflight.
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Affiliation(s)
- Yiding Wang
- State Key Laboratory of Transducer Technology, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing, China
- School of Electronic, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing, China
| | - Yilin Song
- State Key Laboratory of Transducer Technology, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing, China
- School of Electronic, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing, China
| | - Yuchuan Dai
- State Key Laboratory of Transducer Technology, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing, China
- School of Electronic, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing, China
| | - Xinrong Li
- State Key Laboratory of Transducer Technology, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing, China
- School of Electronic, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing, China
| | - Jingyu Xie
- State Key Laboratory of Transducer Technology, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing, China
- School of Electronic, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing, China
| | - Jinping Luo
- State Key Laboratory of Transducer Technology, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing, China
- School of Electronic, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing, China
| | - Chao Yang
- China Astronaut Research and Training Center, Beijing, China
| | - Penghui Fan
- State Key Laboratory of Transducer Technology, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing, China
- School of Electronic, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing, China
| | - Guihua Xiao
- State Key Laboratory of Transducer Technology, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing, China
- School of Electronic, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing, China
| | - Yan Luo
- Department of Anesthesiology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Ying Wang
- Department of Anesthesiology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
- *Correspondence: Xinxia Cai, ; Yinghui Li, ; Ying Wang,
| | - Yinghui Li
- China Astronaut Research and Training Center, Beijing, China
- *Correspondence: Xinxia Cai, ; Yinghui Li, ; Ying Wang,
| | - Xinxia Cai
- State Key Laboratory of Transducer Technology, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing, China
- School of Electronic, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing, China
- *Correspondence: Xinxia Cai, ; Yinghui Li, ; Ying Wang,
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7
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Choukér A, Ngo-Anh TJ, Biesbroek R, Heldmaier G, Heppener M, Bereiter-Hahn J. European space agency's hibernation (torpor) strategy for deep space missions: Linking biology to engineering. Neurosci Biobehav Rev 2021; 131:618-626. [PMID: 34606822 DOI: 10.1016/j.neubiorev.2021.09.054] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 07/10/2021] [Accepted: 09/28/2021] [Indexed: 11/16/2022]
Abstract
Long-duration space missions to Mars will impose extreme stresses of physical and psychological nature on the crew, as well as significant logistical and technical challenges for life support and transportation. Main challenges include optimising overall mass and maintaining crew physical and mental health. These key scopes have been taken up as the baseline for a study by the European Space Agency (ESA) using its Concurrent Design Facility (CDF). It focussed on the biology of hibernation in reducing metabolism and hence stress, and its links to the infrastructure and life support. We concluded that torpor of crew members can reduce the payload with respect to oxygen, food and water but will require monitoring and artificial intelligence (AI) assisted monitoring of the crew. These studies additionally offer new potential applications for patient care on Earth. Keywords: Space flight, concurrent design facility, metabolic reduction.
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Affiliation(s)
- Alexander Choukér
- Laboratory of Translational Research "Stress and Immunity", Department of Anesthesiology, Hospital of the Ludwig-Maximilians-University, Marchioninistrasse 15, 81377, Munich, Germany
| | - Thu Jennifer Ngo-Anh
- Directorate of Human and Robotic Exploration Programmes, European Space Agency, P.O. Box 299, 2200 AG, Noordwijk, the Netherlands
| | - Robin Biesbroek
- Directorate of Technology, Engineering and Quality, European Space Agency, P.O. Box 299, 2200 AG, Noordwijk, the Netherlands
| | - Gerhard Heldmaier
- Animal Physiology, Department of Biology, Marburg University, Karl-von-Frisch-Strasse 8, 35043, Marburg, Germany
| | - Marc Heppener
- (c)/o Directorate of Human and Robotic Exploration Programmes, European Space Agency, P.O. Box 299, 2200 AG, Noordwijk, the Netherlands
| | - Jürgen Bereiter-Hahn
- Institute for Cell Biology and Neurosciences, Goethe University Frankfurt, Max-von-Lauestr. 19, D 6438, Frankfurt Am Main, Germany.
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8
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Rothhaas R, Chung S. Role of the Preoptic Area in Sleep and Thermoregulation. Front Neurosci 2021; 15:664781. [PMID: 34276287 PMCID: PMC8280336 DOI: 10.3389/fnins.2021.664781] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Accepted: 05/28/2021] [Indexed: 12/18/2022] Open
Abstract
Sleep and body temperature are tightly interconnected in mammals: warming up our body helps to fall asleep and the body temperature in turn drops while falling asleep. The preoptic area of the hypothalamus (POA) serves as an essential brain region to coordinate sleep and body temperature. Understanding how these two behaviors are controlled within the POA requires the molecular identification of the involved circuits and mapping their local and brain-wide connectivity. Here, we review our current understanding of how sleep and body temperature are regulated with a focus on recently discovered sleep- and thermo-regulatory POA neurons. We further discuss unresolved key questions including the anatomical and functional overlap of sleep- and thermo-regulatory neurons, their pathways and the role of various signaling molecules. We suggest that analysis of genetically defined circuits will provide novel insights into the mechanisms underlying the coordinated regulation of sleep and body temperature in health and disease.
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Affiliation(s)
- Rebecca Rothhaas
- Department of Neuroscience, Perelman School of Medicine, Chronobiology and Sleep Institute, University of Pennsylvania, Philadelphia, PA, United States
| | - Shinjae Chung
- Department of Neuroscience, Perelman School of Medicine, Chronobiology and Sleep Institute, University of Pennsylvania, Philadelphia, PA, United States
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9
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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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10
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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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11
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Ware JV, Rode KD, Robbins CT, Leise T, Weil CR, Jansen HT. The Clock Keeps Ticking: Circadian Rhythms of Free-Ranging Polar Bears. J Biol Rhythms 2020; 35:180-194. [DOI: 10.1177/0748730419900877] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Life in the Arctic presents organisms with multiple challenges, including extreme photic conditions, cold temperatures, and annual loss and daily movement of sea ice. Polar bears ( Ursus maritimus) evolved under these unique conditions, where they rely on ice to hunt their main prey, seals. However, very little is known about the dynamics of their daily and seasonal activity patterns. For many organisms, activity is synchronized (entrained) to the earth’s day/night cycle, in part via an endogenous (circadian) timekeeping mechanism. The present study used collar-mounted accelerometer and global positioning system data from 122 female polar bears in the Chukchi and Southern Beaufort Seas collected over an 8-year period to characterize activity patterns over the calendar year and to determine if circadian rhythms are expressed under the constant conditions found in the Arctic. We reveal that the majority of polar bears (80%) exhibited rhythmic activity for the duration of their recordings. Collectively within the rhythmic bear cohort, circadian rhythms were detected during periods of constant daylight (June-August; 24.40 ± 1.39 h, mean ± SD) and constant darkness (23.89 ± 1.72 h). Exclusive of denning periods (November-April), the time of peak activity remained relatively stable (acrophases: ~1200-1400 h) for most of the year, suggesting either entrainment or masking. However, activity patterns shifted during the spring feeding and seal pupping season, as evidenced by an acrophase inversion to ~2400 h in April, followed by highly variable timing of activity across bears in May. Intriguingly, despite the dynamic environmental photoperiodic conditions, unpredictable daily timing of prey availability, and high between-animal variability, the average duration of activity (alpha) remained stable (11.2 ± 2.9 h) for most of the year. Together, these results reveal a high degree of behavioral plasticity in polar bears while also retaining circadian rhythmicity. Whether this degree of plasticity will benefit polar bears faced with a loss of sea ice remains to be determined.
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Affiliation(s)
- Jasmine V. Ware
- Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, Washington, USA
- Department of Environment, Government of Nunavut, Igloolik, NU, Canada
| | - Karyn D. Rode
- U.S. Geological Survey, Alaska Science Center, Anchorage, Alaska, USA
| | - Charles T. Robbins
- School of the Environment and School of Biological Sciences, Washington State University, Pullman, Washington, USA
| | - Tanya Leise
- Department of Mathematics and Statistics, Amherst College, Amherst, Massachusetts, USA
| | - Colby R. Weil
- Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, Washington, USA
| | - Heiko T. Jansen
- Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, Washington, USA
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12
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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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13
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Russell TL, Zhang J, Okoniewski M, Franke F, Bichet S, Hierlemann A. Medullary Respiratory Circuit Is Reorganized by a Seasonally-Induced Program in Preparation for Hibernation. Front Neurosci 2019; 13:376. [PMID: 31080399 PMCID: PMC6497738 DOI: 10.3389/fnins.2019.00376] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Accepted: 04/02/2019] [Indexed: 11/13/2022] Open
Abstract
Deep hibernators go through several cycles of profound drops in body temperature during the winter season, with core temperatures sometimes reaching near freezing. Yet unlike non-hibernating mammals, they can sustain breathing rhythms. The physiological processes that make this possible are still not understood. In this study, we focused on the medullary Ventral Respiratory Column of a facultative hibernator, the Syrian hamster. Using shortened day-lengths, we induced a "winter-adapted" physiological state, which is a prerequisite for hibernation. When recording electrophysiological signals from acute slices in the winter-adapted pre-Bötzinger complex (preBötC), spike trains showed higher spike rates, amplitudes, complexity, as well as higher temperature sensitivity, suggesting an increase in connectivity and/or synaptic strength during the winter season. We further examined action potential waveforms and found that the depolarization integral, as measured by the area under the curve, is selectively enhanced in winter-adapted animals. This suggests that a shift in the ion handling kinetics is also being induced by the winter-adaptation program. RNA sequencing of respiratory pre-motor neurons, followed by gene set enrichment analysis, revealed differential regulation and splicing in structural, synaptic, and ion handling genes. Splice junction analysis suggested that differential exon usage is occurring in a select subset of ion handling subunits (ATP1A3, KCNC3, SCN1B), and synaptic structure genes (SNCB, SNCG, RAB3A). Our findings show that the hamster respiratory center undergoes a seasonally-cued alteration in electrophysiological properties, likely protecting against respiratory failure at low temperatures.
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Affiliation(s)
- Thomas L. Russell
- Department of Biosystems Science and Engineering, ETH Zürich, Basel, Switzerland
| | - Jichang Zhang
- Department of Biosystems Science and Engineering, ETH Zürich, Basel, Switzerland
| | | | - Felix Franke
- Department of Biosystems Science and Engineering, ETH Zürich, Basel, Switzerland
| | - Sandrine Bichet
- Friedrich Miescher Institute for Biomedical Research, Department of Histology, Basel, Switzerland
| | - Andreas Hierlemann
- Department of Biosystems Science and Engineering, ETH Zürich, Basel, Switzerland
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14
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Silvani A, Cerri M, Zoccoli G, Swoap SJ. Is Adenosine Action Common Ground for NREM Sleep, Torpor, and Other Hypometabolic States? Physiology (Bethesda) 2019; 33:182-196. [PMID: 29616880 DOI: 10.1152/physiol.00007.2018] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
This review compares two states that lower energy expenditure: non-rapid eye movement (NREM) sleep and torpor. Knowledge on mechanisms common to these states, and particularly on the role of adenosine in NREM sleep, may ultimately open the possibility of inducing a synthetic torpor-like state in humans for medical applications and long-term space travel. To achieve this goal, it will be important, in perspective, to extend the study to other hypometabolic states, which, unlike torpor, can also be experienced by humans.
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Affiliation(s)
- Alessandro Silvani
- Department of Biomedical and Neuromotor Sciences, Alma Mater Studiorum, University of Bologna , Bologna , Italy
| | - Matteo Cerri
- Department of Biomedical and Neuromotor Sciences, Alma Mater Studiorum, University of Bologna , Bologna , Italy.,National Institute of Nuclear Physics (INFN), Section of Bologna, Bologna , Italy
| | - Giovanna Zoccoli
- Department of Biomedical and Neuromotor Sciences, Alma Mater Studiorum, University of Bologna , Bologna , Italy
| | - Steven J Swoap
- Department of Biology, Williams College , Williamstown, Massachusetts
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15
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Galanin neurons in the ventrolateral preoptic area promote sleep and heat loss in mice. Nat Commun 2018; 9:4129. [PMID: 30297727 PMCID: PMC6175893 DOI: 10.1038/s41467-018-06590-7] [Citation(s) in RCA: 134] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 09/07/2018] [Indexed: 01/02/2023] Open
Abstract
The preoptic area (POA) is necessary for sleep, but the fundamental POA circuits have remained elusive. Previous studies showed that galanin (GAL)- and GABA-producing neurons in the ventrolateral preoptic nucleus (VLPO) express cFos after periods of increased sleep and innervate key wake-promoting regions. Although lesions in this region can produce insomnia, high frequency photostimulation of the POAGAL neurons was shown to paradoxically cause waking, not sleep. Here we report that photostimulation of VLPOGAL neurons in mice promotes sleep with low frequency stimulation (1-4 Hz), but causes conduction block and waking at frequencies above 8 Hz. Further, optogenetic inhibition reduces sleep. Chemogenetic activation of VLPOGAL neurons confirms the increase in sleep, and also reduces body temperature. In addition, chemogenetic activation of VLPOGAL neurons induces short-latency sleep in an animal model of insomnia. Collectively, these findings establish a causal role of VLPOGAL neurons in both sleep induction and heat loss.
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16
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The resilient brain and the guardians of sleep: New perspectives on old assumptions. Sleep Med Rev 2018; 39:98-107. [DOI: 10.1016/j.smrv.2017.08.003] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Revised: 07/19/2017] [Accepted: 08/17/2017] [Indexed: 12/24/2022]
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17
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Roda E, Bottone MG, Insolia V, Barni S, Bernocchi G. Changes in the cerebellar cytoarchitecture of hibernating hedgehog Erinaceus europaeus L. (Mammalia): an immunocytochemical approach. EUROPEAN ZOOLOGICAL JOURNAL 2017. [DOI: 10.1080/24750263.2017.1380722] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- E. Roda
- Department of Biology and Biotechnology “L. Spallanzani”, Laboratory of Cell Biology and Neurobiology, University of Pavia, Pavia, Italy
- Laboratory of Clinical & Experimental Toxicology and Poison Control Centre and National Toxicology Information Centre, Toxicology Unit, ICS Maugeri Spa Benefit Corporation, IRCCS of Pavia, Pavia, Italy
| | - M. G. Bottone
- Department of Biology and Biotechnology “L. Spallanzani”, Laboratory of Cell Biology and Neurobiology, University of Pavia, Pavia, Italy
| | - V. Insolia
- Department of Biology and Biotechnology “L. Spallanzani”, Laboratory of Cell Biology and Neurobiology, University of Pavia, Pavia, Italy
| | - S. Barni
- Department of Biology and Biotechnology “L. Spallanzani”, Laboratory of Cell Biology and Neurobiology, University of Pavia, Pavia, Italy
| | - G. Bernocchi
- Department of Biology and Biotechnology “L. Spallanzani”, Laboratory of Cell Biology and Neurobiology, University of Pavia, Pavia, Italy
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18
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Yang SL, Ren QG, Wen L, Hu JL, Wang HY. Research progress on circadian clock genes in common abdominal malignant tumors. Oncol Lett 2017; 14:5091-5098. [PMID: 29113149 PMCID: PMC5661368 DOI: 10.3892/ol.2017.6856] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2016] [Accepted: 07/03/2017] [Indexed: 02/01/2023] Open
Abstract
The circadian clock refers to the inherent biological rhythm of an organism, which, is accurately regulated by numerous clock genes. Studies in recent years have reported that the abnormal expression of clock genes is ubiquitous in common abdominal malignant tumors, including liver, colorectal, gastric and pancreatic cancer. In addition, the abnormal expression of certain clock genes is closely associated with clinical tumor parameters or patient prognosis. Studies in clock genes may expand the knowledge about the mechanism of occurrence and development of tumors, and may provide a new approach for tumor therapy. The present study summarizes the research progress in this field.
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Affiliation(s)
- Sheng-Li Yang
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, P.R. China
| | - Quan-Guang Ren
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, P.R. China
| | - Lu Wen
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, P.R. China
| | - Jian-Li Hu
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, P.R. China
| | - Heng-Yi Wang
- Department of Surgery, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui 230022, P.R. China
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19
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Pineda N, Owen M, Tucker C, Wojda S, Kitchen S, Black H, Donahue S. Hibernating Little Pocket Mice Show Few Seasonal Changes in Bone Properties. Anat Rec (Hoboken) 2017; 300:2175-2183. [PMID: 28806499 DOI: 10.1002/ar.23676] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 05/11/2017] [Accepted: 05/31/2017] [Indexed: 11/09/2022]
Abstract
Periods of disuse or physical inactivity increases bone porosity and decreases bone mineral density, resulting in a loss of bone mechanical competence in many animals. Although large hibernators like bears and marmots prevent bone loss during hibernation, despite long periods of physical inactivity, some small hibernators do lose bone during hibernation. Little pocket mice (Perognathus longimembris) remain underground during winter hibernation and undergo bouts of torpor and interbout arousals, but the torpor bout duration is shorter than other rodent hibernators. Additionally, little pocket mice may enter torpor during summer estivation. In this study, cortical and trabecular bone architectural, mineral, and mechanical properties were analyzed for femurs from little pocket mice captured during 8 different months (March to October) to determine seasonal effects on bone. There were no differences in any bone properties between the pre-hibernation month of October and the post-hibernation month of March, suggesting winter hibernation did not adversely affect bone properties. However, cortical area was higher in March than April, May, and June. Bone mechanical and osteocyte lacunar properties were not different between any months. Trabecular bone in the distal femoral epiphysis showed no changes between months. The distal femoral metaphyseal region showed higher trabecular spacing and lower trabecular number in May than August, otherwise, there were no differences in trabecular parameters. The few monthly differences in bone properties may be due to physical inactivity from periodic summer estivation or from the timing of birth and growth in spring and summer months. Anat Rec, 300:2175-2183, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Noellyn Pineda
- School of Biomedical Engineering, Colorado State University, Fort Collins, Colorado.,Department of Mechanical Engineering, Colorado State University, Fort Collins, Colorado
| | - Marjorie Owen
- Department of Mechanical Engineering, Colorado State University, Fort Collins, Colorado
| | - Claire Tucker
- Department of Mechanical Engineering, Colorado State University, Fort Collins, Colorado
| | - Samantha Wojda
- Department of Mechanical Engineering, Colorado State University, Fort Collins, Colorado
| | - Stanley Kitchen
- US Forest Service, Rocky Mountain Research Station, Provo, Utah
| | - Hal Black
- Department of Plant and Wildlife Sciences, Brigham Young University, Provo, Utah
| | - Seth Donahue
- School of Biomedical Engineering, Colorado State University, Fort Collins, Colorado.,Department of Mechanical Engineering, Colorado State University, Fort Collins, Colorado
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20
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Ikeno T, Williams CT, Buck CL, Barnes BM, Yan L. Clock Gene Expression in the Suprachiasmatic Nucleus of Hibernating Arctic Ground Squirrels. J Biol Rhythms 2017; 32:246-256. [PMID: 28452286 DOI: 10.1177/0748730417702246] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Most organisms have a circadian system, entrained to daily light-dark cycles, that regulates 24-h rhythms of physiology and behavior. It is unclear, however, how circadian systems function in animals that exhibit seasonal metabolic suppression, particularly when this coincides with the long-term absence of a day-night cycle. The arctic ground squirrel, Urocytellus parryii, is a medium-sized, semi-fossorial rodent that appears above-ground daily during its short active season in spring and summer before re-entering a constantly dark burrow for 6 to 9 months of hibernation. This hibernation consists of multiple week-long torpor bouts interrupted by short (< 20 h) arousal intervals when metabolism and body temperature (Tb) return to normal levels. Here, we used immunohistochemistry to measure the expression of daily or circadian rhythms of the protein products of 3 circadian clock genes, PER1, PER2, BMAL1, and the neural activity marker c-FOS in the suprachiasmatic nucleus (SCN) of arctic ground squirrels before, during, and after the first torpor bout of hibernation. Before torpor, while under 12:12-h light:dark conditions, animals showed significant daily rhythms in their Tb, as well as in protein expression levels of PER1 and PER2, but not BMAL1. Upon entering first torpor (Tb < 30°C), animals were moved into constant darkness. When sampled at 6-h intervals-beginning 24 h after the last light out, with Tb 3°C to 4°C-there were no circadian oscillations in PER1, PER2, or c-FOS expression. Sampling across 24 h during the first spontaneous arousal interval, c-FOS expression was elevated only when Tb reached 20°C and PER1 and PER2 expression did not show any Tb- or time-dependent changes. These results suggest that the central circadian clock might have stopped functioning during hibernation in this species, and the timing of arousal from torpor in arctic ground squirrels is unlikely to be controlled by the circadian clock within the SCN.
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Affiliation(s)
- Tomoko Ikeno
- Department of Psychology, Michigan State University, East Lansing, Michigan.,1. Department of Biological Sciences, Graduate School of Science, The University of Tokyo
| | - Cory T Williams
- Department of Biological Sciences & Center for Bioengineering Innovation, Northern Arizona University, Flagstaff, Arizona
| | - C Loren Buck
- Department of Biological Sciences & Center for Bioengineering Innovation, Northern Arizona University, Flagstaff, Arizona
| | - Brian M Barnes
- Institute of Arctic Biology, University of Alaska Fairbanks
| | - Lily Yan
- Department of Psychology, Michigan State University, East Lansing, Michigan.,Neuroscience Program, Michigan State University, East Lansing, Michigan
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21
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Central activation of the A 1 adenosine receptor in fed mice recapitulates only some of the attributes of daily torpor. J Comp Physiol B 2017; 187:835-845. [PMID: 28378088 DOI: 10.1007/s00360-017-1084-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 11/02/2016] [Accepted: 03/07/2017] [Indexed: 01/23/2023]
Abstract
Mice enter bouts of daily torpor, drastically reducing metabolic rate, core body temperature (T b), and heart rate (HR), in response to reduced caloric intake. Because central adenosine activation has been shown to induce a torpor-like state in the arctic ground squirrel, and blocking the adenosine-1 (A1) receptor prevents daily torpor, we hypothesized that central activation of the A1 adenosine receptors would induce a bout of natural torpor in mice. To test the hypothesis, mice were subjected to four different hypothermia bouts: natural torpor, forced hypothermia (FH), isoflurane-anesthesia, and an intracerebroventricular injection of the selective A1 receptor agonist N6-cyclohexyladenosine (CHA). All conditions induced profound hypothermia. T b fell more rapidly in the FH, isoflurane-anesthesia, and CHA conditions compared to torpor, while mice treated with CHA recovered at half the rate of torpid mice. FH, isoflurane-anesthesia, and CHA-treated mice exhibited a diminished drop in HR during entry into hypothermia as compared to torpor. Mice in all conditions except CHA shivered while recovering from hypothermia, and only FH mice shivered substantially while entering hypothermia. Circulating lactate during the hypothermic bouts was not significantly different between the CHA and torpor conditions, both of which had lower than baseline lactate levels. Arrhythmias were largely absent in the FH and isoflurane-anesthesia conditions, while skipped beats were observed in natural torpor and periodic extended (>1 s) HR pauses in the CHA condition. Lastly, the hypothermic bouts showed distinct patterns of gene expression, with torpor characterized by elevated hepatic and cardiac Txnip expression and all other hypothermic states characterized by elevated c-Fos and Egr-1 expression. We conclude that CHA-induced hypothermia and natural torpor are largely different physiological states.
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22
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Seasonal loss and resumption of circadian rhythms in hibernating arctic ground squirrels. J Comp Physiol B 2017; 187:693-703. [PMID: 28332018 DOI: 10.1007/s00360-017-1069-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Revised: 02/04/2017] [Accepted: 02/26/2017] [Indexed: 12/28/2022]
Abstract
Circadian clocks are near universal among organisms and play a key role in coordinating physiological and metabolic functions to anticipate or coincide with predictable daily changes in the physical and social environment. However, whether circadian rhythms persist and are functionally important during hibernation in all mammals is currently unclear. We examined whether circadian rhythms of body temperature (T b) persist during multi-day, steady-state torpor and investigated the association between timing of animal emergence, exposure to light, and resumption of activity and T b rhythms in free-living and captive male arctic ground squirrels. High-resolution (0.02 °C) temperature loggers revealed that circadian rhythms of T b were not present during deep torpor in free-living arctic ground squirrels. Significant circadian rhythms of T b resumed, however, following the resumption of euthermia, but prior to emergence, though rhythms became much more robust coincident with aboveground emergence. Additionally, squirrels maintained in captivity under conditions of constant darkness spontaneously developed significant circadian rhythms of T b and activity soon after ending torpor. Exposing animals to a 5-s pulse of light within a week when they ended torpor increased the strength of rhythms. Our results are consistent with the hypothesis that circadian clock function is inhibited during hibernation in arctic ground squirrels, and we postulate that exposure to external stimuli, such as light in free-living animals, and meals or acute disturbance for captive squirrels, may enhance T b rhythmicity by synchronizing loosely coupled circadian oscillators within the suprachiasmatic nucleus.
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23
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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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Low, but not high, dose caffeine is a readily available probe for adenosine actions. Mol Aspects Med 2016; 55:20-25. [PMID: 27915051 DOI: 10.1016/j.mam.2016.11.011] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Revised: 11/23/2016] [Accepted: 11/23/2016] [Indexed: 12/21/2022]
Abstract
Caffeine is very widely used and knowledge of its mode of action can be used to gain an understanding of basal physiological regulation. This review makes the point that caffeine is - in low doses - an antagonist of adenosine acting at A1, A2A and A2B receptors. We use published and unpublished data to make the point that high dose effects of caffeine are not only qualitatively different but have a different underlying mechanism. Therefore one must be careful in only using epidemiological or experimental data where rather low doses of caffeine are used to draw conclusions about the physiology and pathophysiology of adenosine.
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Abstract
Autonomic thermoregulation is a recently acquired function, as it appears for the first time in mammals and provides the brain with the ability to control energy expenditure. The importance of such control can easily be highlighted by the ability of a heterogeneous group of mammals to actively reduce metabolic rate and enter a condition of regulated hypometabolism known as torpor. The central neural circuits of thermoregulatory cold defense have been recently unraveled and could in theory be exploited to reduce energy expenditure in species that do not normally use torpor, inducing a state called synthetic torpor. This approach may represent the first steps toward the development of a technology to induce a safe and reversible state of hypometabolism in humans, unlocking many applications ranging from new medical procedures to deep space travel.
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Affiliation(s)
- Matteo Cerri
- Department of Biomedical and Neuromotor Sciences, Physiology Division, Alma Mater Studiorum, University of Bologna, 40126 Bologna, Italy;
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26
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Collet TH, van der Klaauw AA, Henning E, Keogh JM, Suddaby D, Dachi SV, Dunbar S, Kelway S, Dickson SL, Farooqi IS, Schmid SM. The Sleep/Wake Cycle is Directly Modulated by Changes in Energy Balance. Sleep 2016; 39:1691-700. [PMID: 27306267 PMCID: PMC4989258 DOI: 10.5665/sleep.6094] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Accepted: 05/19/2016] [Indexed: 02/02/2023] Open
Abstract
STUDY OBJECTIVES The rise in obesity has been paralleled by a decline in sleep duration in epidemiological studies. However, the potential mechanisms linking energy balance and the sleep/wake cycle are not well understood. We aimed to examine the effects of manipulating energy balance on the sleep/wake cycle. METHODS Twelve healthy normal weight men were housed in a clinical research facility and studied at three time points: baseline, after energy balance was disrupted by 2 days of caloric restriction to 10% of energy requirements, and after energy balance was restored by 2 days of ad libitum/free feeding. Sleep architecture, duration of sleep stages, and sleep-associated respiratory parameters were measured by polysomnography. RESULTS Two days of caloric restriction significantly increased the duration of deep (stage 4) sleep (16.8% to 21.7% of total sleep time; P = 0.03); an effect which was entirely reversed upon free feeding (P = 0.01). Although the apnea-hypopnea index stayed within the reference range (< 5 events per hour), it decreased significantly from caloric restriction to free feeding (P = 0.03). Caloric restriction was associated with a marked fall in leptin (P < 0.001) and insulin levels (P = 0.002). The fall in orexin levels from baseline to caloric restriction correlated positively with duration of stage 4 sleep (Spearman rho = 0.83, P = 0.01) and negatively with the number of awakenings in caloric restriction (Spearman rho = -0.79, P = 0.01). CONCLUSIONS We demonstrate that changes in energy homeostasis directly and reversibly impact on the sleep/wake cycle. These findings provide a mechanistic framework for investigating the association between sleep duration and obesity risk.
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Affiliation(s)
- Tinh-Hai Collet
- University of Cambridge Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science and the NIHR Cambridge Biomedical Research Centre, Addenbrooke's Hospital, Cambridge, UK
| | - Agatha A. van der Klaauw
- University of Cambridge Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science and the NIHR Cambridge Biomedical Research Centre, Addenbrooke's Hospital, Cambridge, UK
| | - Elana Henning
- University of Cambridge Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science and the NIHR Cambridge Biomedical Research Centre, Addenbrooke's Hospital, Cambridge, UK
| | - Julia M. Keogh
- University of Cambridge Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science and the NIHR Cambridge Biomedical Research Centre, Addenbrooke's Hospital, Cambridge, UK
| | - Diane Suddaby
- University of Cambridge Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science and the NIHR Cambridge Biomedical Research Centre, Addenbrooke's Hospital, Cambridge, UK
| | - Sekesai V. Dachi
- University of Cambridge Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science and the NIHR Cambridge Biomedical Research Centre, Addenbrooke's Hospital, Cambridge, UK
| | - Síle Dunbar
- University of Cambridge Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science and the NIHR Cambridge Biomedical Research Centre, Addenbrooke's Hospital, Cambridge, UK
| | - Sarah Kelway
- University of Cambridge Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science and the NIHR Cambridge Biomedical Research Centre, Addenbrooke's Hospital, Cambridge, UK
| | - Suzanne L. Dickson
- Institute for Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Sweden
| | - I. Sadaf Farooqi
- University of Cambridge Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science and the NIHR Cambridge Biomedical Research Centre, Addenbrooke's Hospital, Cambridge, UK
| | - Sebastian M. Schmid
- University of Cambridge Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science and the NIHR Cambridge Biomedical Research Centre, Addenbrooke's Hospital, Cambridge, UK
- Department of Internal Medicine, University of Lübeck, Germany
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27
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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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Carlin JL, Tosh DK, Xiao C, Piñol RA, Chen Z, Salvemini D, Gavrilova O, Jacobson KA, Reitman ML. Peripheral Adenosine A3 Receptor Activation Causes Regulated Hypothermia in Mice That Is Dependent on Central Histamine H1 Receptors. J Pharmacol Exp Ther 2016; 356:474-82. [PMID: 26606937 PMCID: PMC4746492 DOI: 10.1124/jpet.115.229872] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Accepted: 11/23/2015] [Indexed: 11/22/2022] Open
Abstract
Adenosine can induce hypothermia, as previously demonstrated for adenosine A1 receptor (A1AR) agonists. Here we use the potent, specific A3AR agonists MRS5698, MRS5841, and MRS5980 to show that adenosine also induces hypothermia via the A3AR. The hypothermic effect of A3AR agonists is independent of A1AR activation, as the effect was fully intact in mice lacking A1AR but abolished in mice lacking A3AR. A3AR agonist-induced hypothermia was attenuated by mast cell granule depletion, demonstrating that the A3AR hypothermia is mediated, at least in part, via mast cells. Central agonist dosing had no clear hypothermic effect, whereas peripheral dosing of a non-brain-penetrant agonist caused hypothermia, suggesting that peripheral A3AR-expressing cells drive the hypothermia. Mast cells release histamine, and blocking central histamine H1 (but not H2 or H4) receptors prevented the hypothermia. The hypothermia was preceded by hypometabolism and mice with hypothermia preferred a cooler environmental temperature, demonstrating that the hypothermic state is a coordinated physiologic response with a reduced body temperature set point. Importantly, hypothermia is not required for the analgesic effects of A3AR agonists, which occur with lower agonist doses. These results support a mechanistic model for hypothermia in which A3AR agonists act on peripheral mast cells, causing histamine release, which stimulates central histamine H1 receptors to induce hypothermia. This mechanism suggests that A3AR agonists will probably not be useful for clinical induction of hypothermia.
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Affiliation(s)
- Jesse Lea Carlin
- Diabetes, Endocrinology, and Obesity Branch (J.L.C., C.X., R.A.P., M.L.R.), Molecular Recognition Section, Laboratory of Bioorganic Chemistry (D.K.T., K.A.J.), and Mouse Metabolism Core (O.G.), National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland; and Department of Pharmacological and Physiological Science, Saint Louis University School of Medicine, St. Louis, Missouri (Z.C., D.S.)
| | - Dilip K Tosh
- Diabetes, Endocrinology, and Obesity Branch (J.L.C., C.X., R.A.P., M.L.R.), Molecular Recognition Section, Laboratory of Bioorganic Chemistry (D.K.T., K.A.J.), and Mouse Metabolism Core (O.G.), National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland; and Department of Pharmacological and Physiological Science, Saint Louis University School of Medicine, St. Louis, Missouri (Z.C., D.S.)
| | - Cuiying Xiao
- Diabetes, Endocrinology, and Obesity Branch (J.L.C., C.X., R.A.P., M.L.R.), Molecular Recognition Section, Laboratory of Bioorganic Chemistry (D.K.T., K.A.J.), and Mouse Metabolism Core (O.G.), National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland; and Department of Pharmacological and Physiological Science, Saint Louis University School of Medicine, St. Louis, Missouri (Z.C., D.S.)
| | - Ramón A Piñol
- Diabetes, Endocrinology, and Obesity Branch (J.L.C., C.X., R.A.P., M.L.R.), Molecular Recognition Section, Laboratory of Bioorganic Chemistry (D.K.T., K.A.J.), and Mouse Metabolism Core (O.G.), National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland; and Department of Pharmacological and Physiological Science, Saint Louis University School of Medicine, St. Louis, Missouri (Z.C., D.S.)
| | - Zhoumou Chen
- Diabetes, Endocrinology, and Obesity Branch (J.L.C., C.X., R.A.P., M.L.R.), Molecular Recognition Section, Laboratory of Bioorganic Chemistry (D.K.T., K.A.J.), and Mouse Metabolism Core (O.G.), National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland; and Department of Pharmacological and Physiological Science, Saint Louis University School of Medicine, St. Louis, Missouri (Z.C., D.S.)
| | - Daniela Salvemini
- Diabetes, Endocrinology, and Obesity Branch (J.L.C., C.X., R.A.P., M.L.R.), Molecular Recognition Section, Laboratory of Bioorganic Chemistry (D.K.T., K.A.J.), and Mouse Metabolism Core (O.G.), National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland; and Department of Pharmacological and Physiological Science, Saint Louis University School of Medicine, St. Louis, Missouri (Z.C., D.S.)
| | - Oksana Gavrilova
- Diabetes, Endocrinology, and Obesity Branch (J.L.C., C.X., R.A.P., M.L.R.), Molecular Recognition Section, Laboratory of Bioorganic Chemistry (D.K.T., K.A.J.), and Mouse Metabolism Core (O.G.), National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland; and Department of Pharmacological and Physiological Science, Saint Louis University School of Medicine, St. Louis, Missouri (Z.C., D.S.)
| | - Kenneth A Jacobson
- Diabetes, Endocrinology, and Obesity Branch (J.L.C., C.X., R.A.P., M.L.R.), Molecular Recognition Section, Laboratory of Bioorganic Chemistry (D.K.T., K.A.J.), and Mouse Metabolism Core (O.G.), National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland; and Department of Pharmacological and Physiological Science, Saint Louis University School of Medicine, St. Louis, Missouri (Z.C., D.S.)
| | - Marc L Reitman
- Diabetes, Endocrinology, and Obesity Branch (J.L.C., C.X., R.A.P., M.L.R.), Molecular Recognition Section, Laboratory of Bioorganic Chemistry (D.K.T., K.A.J.), and Mouse Metabolism Core (O.G.), National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland; and Department of Pharmacological and Physiological Science, Saint Louis University School of Medicine, St. Louis, Missouri (Z.C., D.S.)
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Nowack J, Geiser F. Friends with benefits: the role of huddling in mixed groups of torpid and normothermic animals. ACTA ACUST UNITED AC 2015; 219:590-6. [PMID: 26685170 DOI: 10.1242/jeb.128926] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Accepted: 12/01/2015] [Indexed: 12/24/2022]
Abstract
Huddling and torpor are widely used for minimizing heat loss by mammals. Despite the questionable energetic benefits from social heterothermy of mixed groups of warm normothermic and cold torpid individuals, the heterothermic Australian sugar glider (Petaurus breviceps) rests in such groups during the cold season. To unravel why they might do so, we examined torpor expression of two sugar glider groups of four individuals each in outside enclosures during winter. We observed 79 torpor bouts during 50 days of observation and found that torpor bouts were longer and deeper when all individuals of a group entered torpor together, and therefore infer that they would have saved more energy in comparison to short and shallow solitary torpor bouts. However, all gliders of either group only expressed torpor uniformly in response to food restriction, whereas on most occasions at least one individual per group remained normothermic. Nevertheless, the presence of warm gliders in mixed groups also appears to be of energetic advantage for torpid individuals, because nest box temperature was negatively correlated with the number of torpid gliders, and normothermic individuals kept the nest temperature at a value closer to the threshold for thermoregulatory heat production during torpor. Our study suggests that mixed groups of torpid and normothermic individuals are observed when environmental conditions are adverse but food is available, leading to intermediate energy savings from torpor. However, under especially challenging conditions and when animals are starving, energy savings are maximized by uniform and pronounced expression of torpor.
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Affiliation(s)
- Julia Nowack
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, New South Wales 2351, Australia
| | - Fritz Geiser
- Centre for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, New South Wales 2351, Australia
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30
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van Breukelen F, Martin SL. The Hibernation Continuum: Physiological and Molecular Aspects of Metabolic Plasticity in Mammals. Physiology (Bethesda) 2015; 30:273-81. [DOI: 10.1152/physiol.00010.2015] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Mammals are often considered to be masters of homeostasis, with the ability to maintain a constant internal milieu, despite marked changes in the environment; however, many species exhibit striking physiological and biochemical plasticity in the face of environmental fluctuations. Here, we review metabolic depression and body temperature fluctuation in mammals, with a focus on the extreme example of hibernation in small-bodied eutherian species. Careful exploitation of the phenotypic plasticity of mammals with metabolic flexibility may provide the key to unlocking the molecular secrets of orchestrating and surviving reversible metabolic depression in less plastic species, including humans.
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Affiliation(s)
| | - Sandra L. Martin
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, Colorado
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31
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Czenze ZJ, Willis CKR. Warming up and shipping out: arousal and emergence timing in hibernating little brown bats (Myotis lucifugus). J Comp Physiol B 2015; 185:575-86. [PMID: 25809999 DOI: 10.1007/s00360-015-0900-1] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Revised: 03/08/2015] [Accepted: 03/10/2015] [Indexed: 12/31/2022]
Abstract
Phenology refers to the timing of events in the annual cycle of organisms. For temperate-zone mammals, hibernation is one such event, but little is known about its phenology. Hibernation consists of energy-saving torpor bouts interspersed with energetically expensive arousals to normothermic Tb, and hibernators should benefit from mechanisms which reduce arousal costs and help them time arousals to coincide with foraging opportunities. In a previous study, we showed that, in contrast to hibernating bats from warmer climates, little brown bats (Myotis lucifugus) from central Canada abandon a circadian pattern to arousal in the middle of winter when there is no chance of feeding. Here, we used temperature telemetry to test whether they would re-synchronize arousals with normal foraging time (i.e. sunset) during late winter as the chance of foraging or emergence opportunities improves, and whether they would synchronize arousals with conspecifics, possibly to exploit social thermoregulation. We also used passive transponders to test whether energy reserves and/or sex differences in reproductive timing influence phenology and the sensitivity of emergence timing to environmental cues. In contrast to patterns in mid-winter, after 7 April 2013, bats synchronized arousals with sunset and with conspecifics. Females emerged earlier than males, and females in the best condition emerged first while body condition had no influence on male emergence timing. Both male and female bats appeared to time emergence with falling barometric pressure, a cue that predicts favourable foraging conditions for bats but which, unlike outside temperature, would have been readily detectable by bats inside the hibernaculum. Our results highlight hibernation traits associated with extreme winter energy limitation for insect-eating bats in cold climates and illustrate the influence of reproductive timing and environmental conditions on hibernation energetics and phenology.
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Affiliation(s)
- Zenon J Czenze
- Department of Biology and Centre for Forest-Interdisciplinary Research, University of Winnipeg, Winnipeg, MB, Canada,
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32
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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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Cooper C, Withers P. Ecological consequences of temperature regulation: Why might the mountain pygmy possum Burramys parvus need to hibernate near underground streams? Temperature (Austin) 2014; 1:32-6. [PMID: 27583278 PMCID: PMC4972512 DOI: 10.4161/temp.29292] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Accepted: 05/20/2014] [Indexed: 11/19/2022] Open
Abstract
The mountain pygmy possum (Burramys parvus) is an endangered marsupial restricted to boulder fields in the Australian Alps, where it hibernates under the snow during winter. Understanding its habitat requirements is essential for conservation, so we examine here ecological implications of the thermal consequences of maintaining water balance during the hibernation season. Hibernating mountain pygmy possums arousing to consume water must either drink liquid water or consume snow. If they drink water, then the energy required to warm that water to body temperature (4.18 J g-1 oC−1) increases linearly with mass ingested. If they eat snow, then the energy required melt the snow (latent heat of fusion = 332 J g−1) and then warm it to body temperature is much higher than just drinking. For mountain pygmy possums, these energetic costs are a large proportion (up to 19%) of their average daily metabolic rate during the hibernation period and may dramatically shorten it. If mountain pygmy possums lose water equivalent to 5% of body mass before arousing to rehydrate, then the potential hibernation period is reduced by 30 days for consuming snow compared with 8.6 days for drinking water. The consequences of ingesting snow rather than liquid water are even more severe for juvenile possums. A reduction in the hibernation period can impact on the overwinter survival, a key factor determining demographics and population size. Therefore, habitats with subnivean access to liquid water during winter, such as those with subterranean streams running under boulder fields, may be of particular value.
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Affiliation(s)
- Chrisitne Cooper
- Department of Environment and Agriculture; Curtin University; Perth, WA Australia; Zoology; School of Animal Biology M092; University of Western Australia; Crawley, WA Australia
| | - Philip Withers
- Department of Environment and Agriculture; Curtin University; Perth, WA Australia; Zoology; School of Animal Biology M092; University of Western Australia; Crawley, WA Australia
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34
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Zervanos SM, Maher CR, Florant GL. Effect of body mass on hibernation strategies of woodchucks (Marmota monax). Integr Comp Biol 2013; 54:443-51. [PMID: 24345658 DOI: 10.1093/icb/ict100] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The benefits of mammalian hibernation have been well documented. However, the physiological and ecological costs of torpor have been emphasized only recently as part of a hibernation-optimization hypothesis. This hypothesis predicts that hibernators with greater availability of energy minimize costs of torpor by less frequent utilization of torpor and by maintaining higher body temperatures (T(b)) during torpor. In order to further examine the relationship between body mass and other parameters of hibernation, we present data, collected over a 12-year period, on the hibernation patterns of free-living woodchucks (Marmota monax) in southeastern Pennsylvania. Body mass was positively correlated with T(b) and negatively correlated with percentage of the heterothermic period spent in torpor. Thus, woodchucks with greater mass exhibited less time in torpor as a proportion of their heterothermic period and at higher T(b) than those with lesser mass. This strategy potentially enhances the physiological and physical ability of woodchucks to defend territories, avoid predation, find mates, and complete the reproductive cycle upon emergence from hibernation. Our results further support the hibernation-optimization hypothesis by demonstrating the relationship between body mass and characteristics of torpor and contributing toward a fuller understanding of this concept.
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Affiliation(s)
- Stam M Zervanos
- *Department of Biology, Pennsylvania State University/Berks, PO Box 7009, Reading, PA 19610-6009, USA; Department of Biological Sciences, University of Southern Maine, Portland, ME 04104, USA; Department of Biology, Colorado State University, Ft. Collins, CO 80523, USA
| | - Christine R Maher
- *Department of Biology, Pennsylvania State University/Berks, PO Box 7009, Reading, PA 19610-6009, USA; Department of Biological Sciences, University of Southern Maine, Portland, ME 04104, USA; Department of Biology, Colorado State University, Ft. Collins, CO 80523, USA
| | - Gregory L Florant
- *Department of Biology, Pennsylvania State University/Berks, PO Box 7009, Reading, PA 19610-6009, USA; Department of Biological Sciences, University of Southern Maine, Portland, ME 04104, USA; Department of Biology, Colorado State University, Ft. Collins, CO 80523, USA
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35
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Xu Y, Shao C, Fedorov VB, Goropashnaya AV, Barnes BM, Yan J. Molecular signatures of mammalian hibernation: comparisons with alternative phenotypes. BMC Genomics 2013; 14:567. [PMID: 23957789 PMCID: PMC3751779 DOI: 10.1186/1471-2164-14-567] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Accepted: 08/17/2013] [Indexed: 12/12/2022] Open
Abstract
Background Mammalian hibernators display phenotypes similar to physiological responses to calorie restriction and fasting, sleep, cold exposure, and ischemia-reperfusion in non-hibernating species. Whether biochemical changes evident during hibernation have parallels in non-hibernating systems on molecular and genetic levels is unclear. Results We identified the molecular signatures of torpor and arousal episodes during hibernation using a custom-designed microarray for the Arctic ground squirrel (Urocitellus parryii) and compared them with molecular signatures of selected mouse phenotypes. Our results indicate that differential gene expression related to metabolism during hibernation is associated with that during calorie restriction and that the nuclear receptor protein PPARα is potentially crucial for metabolic remodeling in torpor. Sleep-wake cycle-related and temperature response genes follow the same expression changes as during the torpor-arousal cycle. Increased fatty acid metabolism occurs during hibernation but not during ischemia-reperfusion injury in mice and, thus, might contribute to protection against ischemia-reperfusion during hibernation. Conclusions In this study, we systematically compared hibernation with alternative phenotypes to reveal novel mechanisms that might be used therapeutically in human pathological conditions.
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Affiliation(s)
- Yichi Xu
- CAS-MPG Partner Institute for Computational Biology, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, 320 Yue Yang Road, Shanghai 200031, China
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The histaminergic network in the brain: basic organization and role in disease. Nat Rev Neurosci 2013; 14:472-87. [DOI: 10.1038/nrn3526] [Citation(s) in RCA: 225] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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37
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Hope PR, Jones G. An entrained circadian cycle of peak activity in a population of hibernating bats. J Mammal 2013. [DOI: 10.1644/12-mamm-a-095.1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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38
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Cerri M, Mastrotto M, Tupone D, Martelli D, Luppi M, Perez E, Zamboni G, Amici R. The inhibition of neurons in the central nervous pathways for thermoregulatory cold defense induces a suspended animation state in the rat. J Neurosci 2013; 33:2984-93. [PMID: 23407956 PMCID: PMC6619194 DOI: 10.1523/jneurosci.3596-12.2013] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Revised: 12/19/2012] [Accepted: 12/20/2012] [Indexed: 12/19/2022] Open
Abstract
The possibility of inducing a suspended animation state similar to natural torpor would be greatly beneficial in medical science, since it would avoid the adverse consequence of the powerful autonomic activation evoked by external cooling. Previous attempts to systemically inhibit metabolism were successful in mice, but practically ineffective in nonhibernators. Here we show that the selective pharmacological inhibition of key neurons in the central pathways for thermoregulatory cold defense is sufficient to induce a suspended animation state, resembling natural torpor, in a nonhibernator. In rats kept at an ambient temperature of 15°C and under continuous darkness, the prolonged inhibition (6 h) of the rostral ventromedial medulla, a key area of the central nervous pathways for thermoregulatory cold defense, by means of repeated microinjections (100 nl) of the GABA(A) agonist muscimol (1 mm), induced the following: (1) a massive cutaneous vasodilation; (2) drastic drops in deep brain temperature (reaching a nadir of 22.44 ± 0.74°C), heart rate (from 440 ± 13 to 207 ± 12 bpm), and electroencephalography (EEG) power; (3) a modest decrease in mean arterial pressure; and (4) a progressive shift of the EEG power spectrum toward slow frequencies. After the hypothermic bout, all animals showed a massive increase in NREM sleep Delta power, similarly to that occurring in natural torpor. No behavioral abnormalities were observed in the days following the treatment. Our results strengthen the potential role of the CNS in the induction of hibernation/torpor, since CNS-driven changes in organ physiology have been shown to be sufficient to induce and maintain a suspended animation state.
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Affiliation(s)
- Matteo Cerri
- Department of Biomedical and NeuroMotor Sciences, Alma Mater Studiorum-University of Bologna, 40126 Bologna Italy.
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Fujita S, Okamoto R, Taniguchi M, Ban-Tokuda T, Konishi K, Goto I, Yamamoto Y, Sugimoto K, Takamatsu N, Nakamura M, Shiraki K, Buechler C, Ito M. Identification of bovine hibernation-specific protein complex and evidence of its regulation in fasting and aging. J Biochem 2013; 153:453-61. [PMID: 23389309 DOI: 10.1093/jb/mvt008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Hibernation-specific protein (HP) is a plasma protein that regulates hibernation in chipmunks. The HP complex (HP20c) consists of three homologous proteins, HP20, HP25 and HP27, all produced by liver and belonging to the C1q family. To date, HP20c has not been identified in any mammalian species except chipmunk and ground squirrel hibernators. Here, we report a bovine HP20 gene isolated from liver tissue and aortic endothelial cells. Total homology between bovine and chipmunk variants was 63% at the amino acid level. Gene expression was highest in the liver. Western blot revealed HP20 protein in foetal, newborn, calf and adult serum, with highest concentrations in the adult. Similar proteins were detected in sera of other ruminants but not in humans, bears, mice or rats. Bovine HP20 protein was found mainly in ovaries, stomach, heart, kidneys, lungs, testes and prostate, but not in the skeletal muscle. Native HP20 was purified from bovine adult serum as a complex containing 25 and 27 kDa proteins. Mass spectrometry revealed that these proteins are orthologues of chipmunk HP25 and HP27, respectively. Interestingly, bovine HP20 was highly expressed in cattle serum after fasting. Native bovine HP20c may be a useful tool for investigating HP function.
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Affiliation(s)
- Satoshi Fujita
- Department of Cardiology and Nephrology, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu, Mie 514-8507, Japan
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40
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Thompson AB, Montiglio PO, Humphries MM. Behavioural impacts of torpor expression: A transient effect in captive eastern chipmunks (Tamias striatus). Physiol Behav 2013; 110-111:115-21. [DOI: 10.1016/j.physbeh.2013.01.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2012] [Revised: 12/03/2012] [Accepted: 01/06/2013] [Indexed: 01/03/2023]
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41
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Johnson JS, Lacki MJ, Thomas SC, Grider JF. Frequent arousals from winter torpor in Rafinesque's big-eared bat (Corynorhinus rafinesquii). PLoS One 2012. [PMID: 23185427 PMCID: PMC3504087 DOI: 10.1371/journal.pone.0049754] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Extensive use of torpor is a common winter survival strategy among bats; however, data comparing various torpor behaviors among species are scarce. Winter torpor behaviors are likely to vary among species with different physiologies and species inhabiting different regional climates. Understanding these differences may be important in identifying differing susceptibilities of species to white-nose syndrome (WNS) in North America. We fitted 24 Rafinesque’s big-eared bats (Corynorhinus rafinesquii) with temperature-sensitive radio-transmitters, and monitored 128 PIT-tagged big-eared bats, during the winter months of 2010 to 2012. We tested the hypothesis that Rafinesque’s big-eared bats use torpor less often than values reported for other North American cave-hibernators. Additionally, we tested the hypothesis that Rafinesque’s big-eared bats arouse on winter nights more suitable for nocturnal foraging. Radio-tagged bats used short (2.4 d ± 0.3 (SE)), shallow (13.9°C ± 0.6) torpor bouts and switched roosts every 4.1 d ± 0.6. Probability of arousal from torpor increased linearly with ambient temperature at sunset (P<0.0001), and 83% (n = 86) of arousals occurred within 1 hr of sunset. Activity of PIT-tagged bats at an artificial maternity/hibernaculum roost between November and March was positively correlated with ambient temperature at sunset (P<0.0001), with males more active at the roost than females. These data show Rafinesque’s big-eared bat is a shallow hibernator and is relatively active during winter. We hypothesize that winter activity patterns provide Corynorhinus species with an ecological and physiological defense against the fungus causing WNS, and that these bats may be better suited to withstand fungal infection than other cave-hibernating bat species in eastern North America.
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Affiliation(s)
- Joseph S Johnson
- Department of Forestry, University of Kentucky, Lexington, Kentucky, United States of America.
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Iliff BW, Swoap SJ. Central adenosine receptor signaling is necessary for daily torpor in mice. Am J Physiol Regul Integr Comp Physiol 2012; 303:R477-84. [PMID: 22785425 DOI: 10.1152/ajpregu.00081.2012] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
When calorically restricted at cool ambient temperatures, mice conserve energy by entering torpor, during which metabolic rate (MR), body temperature (T(b)), heart rate (HR), and locomotor activity (LMA) decrease. Treatment with exogenous adenosine produces a similar hypometabolic state. In this study, we conducted a series of experiments using the nonspecific adenosine receptor antagonists aminophylline and 8-sulfophenyltheophylline (8-SPT) to test the hypothesis that adenosine signaling is necessary for torpor in fasted mice. In the first experiment, mice were subcutaneously infused with aminophylline while T(b), HR, and LMA were continuously monitored using implanted radiotelemeters. During a 23-h fast, saline-treated mice were torpid for 518 ± 43 min, whereas aminophylline-treated mice were torpid for significantly less time (54 ± 20 min). In a second experiment, aminophylline was infused subcutaneously into torpid mice to test the role of adenosine in the maintenance of torpor. Aminophylline reversed the hypometabolism, hypothermia, bradycardia, and hypoactivity of torpor, whereas saline did not. In the third and fourth experiments, the polar adenosine antagonist 8-SPT, which does not cross the blood-brain barrier, was infused either subcutaneously or intracerebroventricularly to test the hypothesis that both peripheral and central adenosine receptor signaling are necessary for the maintenance of torpor. Intracerebroventricular, but not subcutaneous, infusion of 8-SPT causes a return to euthermia. These findings support the hypothesis that adenosine is necessary for torpor in mice and further suggest that whereas peripheral adenosine signaling is not necessary for the maintenance of torpor, antagonism of central adenosine is sufficient to disrupt torpor.
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Affiliation(s)
- Benjamin W Iliff
- Department of Biology, Williams College, Williamstown, MA 01267, USA
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Williams CT, Barnes BM, Richter M, Buck CL. Hibernation and Circadian Rhythms of Body Temperature in Free-Living Arctic Ground Squirrels. Physiol Biochem Zool 2012; 85:397-404. [DOI: 10.1086/666509] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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44
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Warming up for dinner: torpor and arousal in hibernating Natterer's bats (Myotis nattereri) studied by radio telemetry. J Comp Physiol B 2011; 182:569-78. [PMID: 22124860 DOI: 10.1007/s00360-011-0631-x] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2011] [Revised: 11/03/2011] [Accepted: 11/09/2011] [Indexed: 10/15/2022]
Abstract
The frequency and function of arousals during hibernation in free-living mammals are little known. We used temperature-sensitive radio transmitters to measure patterns of torpor, arousal and activity in wild Natterer's bats Myotis nattereri during hibernation. Duration of torpor bouts ranged from 0.06 to 20.4 days with individual means ranging from 0.9 to 8.9 days. Arousals from torpor occurred most commonly coincident with the time (relative to sunset) typical for bats emerging from summer roosts to forage. Bats with lower body condition indices had a shorter average duration of their torpor bouts. We found a non-linear relationship between duration of torpor bout and ambient temperature: the longest average torpor bouts were at temperatures between 2 and 4°C with shorter bouts at lower and higher ambient temperatures. One individual was radio-tracked for ten nights, remained active for an average of 297 min each night and was active for longer on warmer nights. Our results suggest that vespertilionid bats use relatively short torpor bouts during hibernation in a location with a maritime climate. We hypothesise that Natterer's bats time arousals to maximise opportunities for potential foraging during winter although winter feeding is not the sole determinant of arousal as bats still arouse at times when foraging is unlikely.
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Williams CT, Barnes BM, Buck CL. Daily body temperature rhythms persist under the midnight sun but are absent during hibernation in free-living arctic ground squirrels. Biol Lett 2011; 8:31-4. [PMID: 21752811 DOI: 10.1098/rsbl.2011.0435] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
In indigenous arctic reindeer and ptarmigan, circadian rhythms are not expressed during the constant light of summer or constant dark of winter, and it has been hypothesized that a seasonal absence of circadian rhythms is common to all vertebrate residents of polar regions. Here, we show that, while free-living arctic ground squirrels do not express circadian rhythms during the heterothermic and pre-emergent euthermic intervals of hibernation, they display entrained daily rhythms of body temperature (T(b)) throughout their active season, which includes six weeks of constant sun. In winter, ground squirrels are arrhythmic and regulate core body temperatures to within ±0.2°C for up to 18 days during steady-state torpor. In spring, after the use of torpor ends, male but not female ground squirrels, resume euthermic levels of T(b) in their dark burrows but remain arrhythmic for up to 27 days. However, once activity on the surface begins, both sexes exhibit robust 24 h cycles of body temperature. We suggest that persistence of nycthemeral rhythms through the polar summer enables ground squirrels to minimize thermoregulatory costs. However, the environmental cues (zeitgebers) used to entrain rhythms during the constant light of the arctic summer in these semi-fossorial rodents are unknown.
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Affiliation(s)
- Cory T Williams
- Department of Biological Sciences, University of Alaska Anchorage, Anchorage, AK 99508, USA.
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Healy JE, Bateman JL, Ostrom CE, Florant GL. Peripheral ghrelin stimulates feeding behavior and positive energy balance in a sciurid hibernator. Horm Behav 2011; 59:512-9. [PMID: 21310157 PMCID: PMC3081408 DOI: 10.1016/j.yhbeh.2011.01.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Revised: 01/17/2011] [Accepted: 01/31/2011] [Indexed: 01/23/2023]
Abstract
Hibernators exhibit a robust circannual cycle of body mass gain and loss primarily mediated by food intake, but the pathways controlling food intake in these animals have not been fully elucidated. Ghrelin is an orexigenic hormone that increases feeding in all mammals studied so far, but has not until recently been studied in hibernators. In other mammals, ghrelin stimulates feeding through phosphorylation and activation of AMP-activated protein kinase (AMPK). Activation of AMPK phosphorylates and deactivates acetyl Co-A carboxylase (ACC), a committed step in fatty acid synthesis. In order to determine the effects of exogenous ghrelin on food intake and metabolic factors (i.e. non-esterified fatty acids (NEFAs), and hypothalamic AMPK and ACC) in hibernators, ghrelin was peripherally injected into ground squirrels in all four seasons. Changes in food intake and body mass were recorded over a 2-6 hour period post injections, and squirrels were euthanized. Brains and blood were removed, and Western blots were performed to determine changes in phosphorylation of hypothalamic AMPK and ACC. A colorimetric assay was used to determine changes in concentration of serum NEFAs. We found that food intake, body mass, and locomotor activity significantly increased with ghrelin injections versus saline-injected controls, even in animals injected during their aphagic winter season. Injected ghrelin was correlated with increased phosphorylation of AMPK, but didn't have an effect on ACC in winter. Ghrelin-injected animals also had increased levels of serum NEFAs compared with saline controls. This study is the first to show an effect of injected ghrelin on a hibernator.
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Affiliation(s)
- Jessica E Healy
- Department of Biology, Colorado State University, Fort Collins, CO 85023, USA.
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Torterolo P, Lagos P, Monti JM. Melanin-concentrating hormone: a new sleep factor? Front Neurol 2011; 2:14. [PMID: 21516258 PMCID: PMC3080035 DOI: 10.3389/fneur.2011.00014] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Accepted: 03/02/2011] [Indexed: 12/18/2022] Open
Abstract
Neurons containing the neuropeptide melanin-concentrating hormone (MCH) are mainly located in the lateral hypothalamus and the incerto-hypothalamic area, and have widespread projections throughout the brain. While the biological functions of this neuropeptide are exerted in humans through two metabotropic receptors, the MCHR1 and MCHR2, only the MCHR1 is present in rodents. Recently, it has been shown that the MCHergic system is involved in the control of sleep. We can summarize the experimental findings as follows: (1) The areas related to the control of sleep and wakefulness have a high density of MCHergic fibers and receptors. (2) MCHergic neurons are active during sleep, especially during rapid eye movement (REM) sleep. (3) MCH knockout mice have less REM sleep, notably under conditions of negative energy balance. Animals with genetically inactivated MCHR1 also exhibit altered vigilance state architecture and sleep homeostasis. (4) Systemically administered MCHR1 antagonists reduce sleep. (5) Intraventricular microinjection of MCH increases both slow wave sleep (SWS) and REM sleep; however, the increment in REM sleep is more pronounced. (6) Microinjection of MCH into the dorsal raphe nucleus increases REM sleep time. REM seep is inhibited by immunoneutralization of MCH within this nucleus. (7) Microinjection of MCH in the nucleus pontis oralis of the cat enhances REM sleep time and reduces REM sleep latency. All these data strongly suggest that MCH has a potent role in the promotion of sleep. Although both SWS and REM sleep are facilitated by MCH, REM sleep seems to be more sensitive to MCH modulation.
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Affiliation(s)
- Pablo Torterolo
- Department of Physiology, School of Medicine, University of the Republic Montevideo, Uruguay
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Giusi G, Crudo M, Di Vito A, Facciolo RM, Garofalo F, Chew SF, Ip YK, Canonaco M. Lungfish aestivating activities are locked in distinct encephalic γ-aminobutyric acid type A receptor α subunits. J Neurosci Res 2011; 89:418-28. [PMID: 21259328 DOI: 10.1002/jnr.22553] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2010] [Revised: 09/06/2010] [Accepted: 10/20/2010] [Indexed: 01/12/2023]
Abstract
Ammonia in dipnoans plays a crucial role on neuronal homeostasis, especially for those brain areas that maintain torpor and awakening states in equilibrium. In the present study, specific α subunits of the major neuroreceptor inhibitory complex (GABA(A) R), which predominated during some phases of aestivation of the lungfish Protopterus annectens, turned out to be key adaptive factors of this species. From the isolation, for the first time, of the encoding sequence for GABA(A) R α₁, α₄ , and α₅ subunits in Protopterus annectens, qPCR and in situ hybridization levels of α₄ transcript in thalamic (P < 0.001) and mesencephalic (P < 0.01) areas proved to be significantly higher during long aestivating maintenance states. Very evident α₅ mRNA levels were detected in diencephalon during short inductive aestivating states, whereas an α₄ /α₁ turnover characterized the arousal state. Contextually, the recovery of physiological activities appeared to be tightly related to an evident up-regulation of α₁ transcripts in telencephalic and cerebellar sites. Surprisingly, TUNEL and amino cupric silver methods corroborated apoptotic and neurodegenerative cellular events, respectively, above all in telencephalon and cerebellum of lungfish exposed to long maintenance aestivating conditions. Overall, these results tend to underlie a novel GABAergic-related ON/OFF molecular switch operating during aestivation of the lungfish, which might have a bearing on sleeping disorders.
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Affiliation(s)
- Giuseppina Giusi
- Comparative Neuroanatomy Laboratory, University of Calabria, Arcavacata di Rende (CS), Italy
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Fredholm BB, Johansson S, Wang YQ. Adenosine and the Regulation of Metabolism and Body Temperature. ADVANCES IN PHARMACOLOGY 2011; 61:77-94. [DOI: 10.1016/b978-0-12-385526-8.00003-5] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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Malan A. Is the torpor-arousal cycle of hibernation controlled by a non-temperature-compensated circadian clock? J Biol Rhythms 2010; 25:166-75. [PMID: 20484688 DOI: 10.1177/0748730410368621] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
During the hibernation season, mammalian hibernators alternate between prolonged bouts of torpor with a reduced body temperature (Tb) and short arousals with a return to euthermy. Evidence is presented here to show that this metabolic-and also physiological and neuroanatomical-rhythm is controlled by a clock, the torpor-arousal (TA) clock. The temperature dependence of torpor bout duration in 3 species of Spermophilus (published data) may be described by assuming that the TA clock is a circadian clock (probably not the suprachiasmatic clock) that has lost its temperature compensation. This loss might result either from a permanent deletion, or more likely from a seasonal epigenetic control at the level of the clock gene machinery. This hypothesis was verified over the full Tb range on published data from 5 other species (a monotreme, a marsupial, and 3 placental mammals). In a hibernation season, instantaneous subjective time of the putative TA clock was summated over each torpor bout. For each animal, torpor bout length (TBL) was accurately predicted as a constant fraction of a subjective day, for actual durations in astronomical time varying between 4 and 13 to 20 days. The resulting temperature dependence of the interval between arousals predicts that energy expenditure over the hibernation season will be minimal when Tb is as low as possible without eliciting cold thermogenesis.
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Affiliation(s)
- André Malan
- Institute of Cellular and Integrative Neurosciences, CNRS (National Center for Scientific Research) and University of Strasbourg, France.
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