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Rae CD, Baur JA, Borges K, Dienel G, Díaz-García CM, Douglass SR, Drew K, Duarte JMN, Duran J, Kann O, Kristian T, Lee-Liu D, Lindquist BE, McNay EC, Robinson MB, Rothman DL, Rowlands BD, Ryan TA, Scafidi J, Scafidi S, Shuttleworth CW, Swanson RA, Uruk G, Vardjan N, Zorec R, McKenna MC. Brain energy metabolism: A roadmap for future research. J Neurochem 2024; 168:910-954. [PMID: 38183680 PMCID: PMC11102343 DOI: 10.1111/jnc.16032] [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: 05/27/2023] [Revised: 11/29/2023] [Accepted: 12/05/2023] [Indexed: 01/08/2024]
Abstract
Although we have learned much about how the brain fuels its functions over the last decades, there remains much still to discover in an organ that is so complex. This article lays out major gaps in our knowledge of interrelationships between brain metabolism and brain function, including biochemical, cellular, and subcellular aspects of functional metabolism and its imaging in adult brain, as well as during development, aging, and disease. The focus is on unknowns in metabolism of major brain substrates and associated transporters, the roles of insulin and of lipid droplets, the emerging role of metabolism in microglia, mysteries about the major brain cofactor and signaling molecule NAD+, as well as unsolved problems underlying brain metabolism in pathologies such as traumatic brain injury, epilepsy, and metabolic downregulation during hibernation. It describes our current level of understanding of these facets of brain energy metabolism as well as a roadmap for future research.
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Affiliation(s)
- Caroline D. Rae
- School of Psychology, The University of New South Wales, NSW 2052 & Neuroscience Research Australia, Randwick, New South Wales, Australia
| | - Joseph A. Baur
- Department of Physiology and Institute for Diabetes, Obesity and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Karin Borges
- School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, St Lucia, QLD, Australia
| | - Gerald Dienel
- Department of Neurology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
- Department of Cell Biology and Physiology, University of New Mexico School of Medicine, Albuquerque, New Mexico, USA
| | - Carlos Manlio Díaz-García
- Department of Biochemistry and Molecular Biology, Center for Geroscience and Healthy Brain Aging, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | | | - Kelly Drew
- Center for Transformative Research in Metabolism, Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, Alaska, USA
| | - João M. N. Duarte
- Department of Experimental Medical Science, Faculty of Medicine, Lund University, Lund, & Wallenberg Centre for Molecular Medicine, Lund University, Lund, Sweden
| | - Jordi Duran
- Institut Químic de Sarrià (IQS), Universitat Ramon Llull (URL), Barcelona, Spain
- Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Oliver Kann
- Institute of Physiology and Pathophysiology, University of Heidelberg, D-69120; Interdisciplinary Center for Neurosciences (IZN), University of Heidelberg, Heidelberg, Germany
| | - Tibor Kristian
- Veterans Affairs Maryland Health Center System, Baltimore, Maryland, USA
- Department of Anesthesiology and the Center for Shock, Trauma, and Anesthesiology Research (S.T.A.R.), University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Dasfne Lee-Liu
- Facultad de Medicina y Ciencia, Universidad San Sebastián, Santiago, Región Metropolitana, Chile
| | - Britta E. Lindquist
- Department of Neurology, Division of Neurocritical Care, Gladstone Institute of Neurological Disease, University of California at San Francisco, San Francisco, California, USA
| | - Ewan C. McNay
- Behavioral Neuroscience, University at Albany, Albany, New York, USA
| | - Michael B. Robinson
- Departments of Pediatrics and System Pharmacology & Translational Therapeutics, Children’s Hospital of Philadelphia, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Douglas L. Rothman
- Magnetic Resonance Research Center and Departments of Radiology and Biomedical Engineering, Yale University, New Haven, Connecticut, USA
| | - Benjamin D. Rowlands
- School of Chemistry, Faculty of Science, The University of Sydney, Sydney, New South Wales, Australia
| | - Timothy A. Ryan
- Department of Biochemistry, Weill Cornell Medicine, New York, New York, USA
| | - Joseph Scafidi
- Department of Neurology, Kennedy Krieger Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Susanna Scafidi
- Anesthesiology & Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - C. William Shuttleworth
- Department of Neurosciences, University of New Mexico School of Medicine Albuquerque, Albuquerque, New Mexico, USA
| | - Raymond A. Swanson
- Department of Neurology, University of California, San Francisco, and San Francisco Veterans Affairs Medical Center, San Francisco, California, USA
| | - Gökhan Uruk
- Department of Neurology, University of California, San Francisco, and San Francisco Veterans Affairs Medical Center, San Francisco, California, USA
| | - Nina Vardjan
- Laboratory of Cell Engineering, Celica Biomedical, Ljubljana, Slovenia
- Laboratory of Neuroendocrinology—Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Robert Zorec
- Laboratory of Cell Engineering, Celica Biomedical, Ljubljana, Slovenia
- Laboratory of Neuroendocrinology—Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Mary C. McKenna
- Department of Pediatrics and Program in Neuroscience, University of Maryland School of Medicine, Baltimore, Maryland, USA
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Devereaux MEM, Pamenter ME. Adenosine and γ-aminobutyric acid partially regulate metabolic and ventilatory responses of Damaraland mole-rats to acute hypoxia. J Exp Biol 2023; 226:jeb246186. [PMID: 37694288 PMCID: PMC10565114 DOI: 10.1242/jeb.246186] [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: 05/24/2023] [Accepted: 09/01/2023] [Indexed: 09/12/2023]
Abstract
Fossorial Damaraland mole-rats (Fukomys damarensis) mount a robust hypoxic metabolic response (HMR) but a blunted hypoxic ventilatory response (HVR) to acute hypoxia. Although these reflex physiological responses have been described previously, the underlying signalling pathways are entirely unknown. Of particular interest are contributions from γ-aminobutyric acid (GABA), which is the primary inhibitory neurotransmitter in the nervous system of most adult mammals, and adenosine, the accumulation of which increases during hypoxia as a breakdown product of ATP. Therefore, we hypothesized that GABAergic and/or adenosinergic signalling contributes to the blunted HVR and robust HMR in Damaraland mole-rats. To test this hypothesis, we injected adult animals with saline alone (controls), or 100 mg kg-1 aminophylline or 1 mg kg-1 bicuculline, to block adenosine or GABAA receptors, respectively. We then used respirometry, plethysmography and thermal RFID probes to non-invasively measure metabolic, ventilator and thermoregulatory responses, respectively, to acute hypoxia (1 h in 5 or 7% O2) in awake and freely behaving animals. We found that bicuculline had relatively minor effects on metabolism and thermoregulation but sensitized ventilation such that the HVR became manifest at 7% instead of 5% O2 and was greater in magnitude. Aminophylline increased metabolic rate, ventilation and body temperature in normoxia, and augmented the HMR and HVR. Taken together, these findings indicate that adenosinergic and GABAergic signalling play important roles in mediating the robust HMR and blunted HVR in Damaraland mole-rats.
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Affiliation(s)
| | - Matthew E. Pamenter
- Department of Biology, University of Ottawa, Ottawa, ON K1N 6N5, Canada
- University of Ottawa Brain and Mind Research Institute, Ottawa, ON K1H 8M5, Canada
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Kamata T, Yamada S, Sekijima T. Differential AMPK-mediated metabolic regulation observed in hibernation-style polymorphisms in Siberian chipmunks. Front Physiol 2023; 14:1220058. [PMID: 37664438 PMCID: PMC10468594 DOI: 10.3389/fphys.2023.1220058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 08/07/2023] [Indexed: 09/05/2023] Open
Abstract
Hibernation is a unique physiological phenomenon allowing extreme hypothermia in endothermic mammals. Hypometabolism and hypothermia tolerance in hibernating animals have been investigated with particular interest; recently, studies of cultured cells and manipulation of the nervous system have made it possible to reproduce physiological states related to hypothermia induction. However, much remains unknown about the periodic regulation of hibernation. In particular, the physiological mechanisms facilitating the switch from an active state to a hibernation period, including behavioral changes and the acquisition of hypothermia tolerance remain to be elucidated. AMPK is a protein known to play a central role not only in feeding behavior but also in metabolic regulation in response to starvation. Our previous research has revealed that chipmunks activate AMPK in the brain during hibernation. However, whether AMPK is activated during winter in non-hibernating animals is unknown. Previous comparative studies between hibernating and non-hibernating animals have often been conducted between different species, consequently it has been impossible to account for the effects of phylogenetic differences. Our long-term monitoring of siberian chipmunks, has revealed intraspecific variation between those individuals that hibernate annually and those that never become hypothermic. Apparent differences were found between hibernating and non-hibernating types with seasonal changes in lifespan and blood HP levels. By comparing seasonal changes in AMPK activity between these polymorphisms, we clarified the relationship between hibernation and AMPK regulation. In hibernating types, phosphorylation of p-AMPK and p-ACC was enhanced throughout the brain during hibernation, indicating that AMPK-mediated metabolic regulation is activated. In non-hibernating types, AMPK and ACC were not seasonally activated. In addition, AMPK activation in the hypothalamus had already begun during high Tb before hibernation. Changes in AMPK activity in the brain during hibernation may be driven by circannual rhythms, suggesting a hibernation-regulatory mechanism involving AMPK activation independent of Tb. The differences in brain AMPK regulation between hibernators and non-hibernators revealed in this study were based on a single species thus did not involve phylogenetic differences, thereby supporting the importance of brain temperature-independent AMPK activation in regulating seasonal metabolism in hibernating animals.
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Affiliation(s)
- Taito Kamata
- Graduate School of Science and Technology, Niigata University, Niigata, Japan
- Faculty of Agriculture, Niigata University, Niigata, Japan
| | - Shintaro Yamada
- Graduate School of Science and Technology, Niigata University, Niigata, Japan
- Institute of Biomedical Science, Kansai Medical University, Osaka, Japan
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Ma WX, Yuan PC, Zhang H, Kong LX, Lazarus M, Qu WM, Wang YQ, Huang ZL. Adenosine and P1 receptors: Key targets in the regulation of sleep, torpor, and hibernation. Front Pharmacol 2023; 14:1098976. [PMID: 36969831 PMCID: PMC10036772 DOI: 10.3389/fphar.2023.1098976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 02/27/2023] [Indexed: 03/12/2023] Open
Abstract
Graphical AbstractAdenosine mediates sleep, torpor and hibernation through P1 receptors. Recent reasearch has shown that P1 receptors play a vital role in the regulation of sleep-wake, torpor and hibernation-like states. In this review, we focus on the roles and neurobiological mechanisms of the CNS adenosine and P1 receptors in these three states. Among them, A1 and A2A receptors are key targets for sleep-wake regulation, A1Rs and A3Rs are very important for torpor induction, and activation of A1Rs is sufficient for hibernation-like state.
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Affiliation(s)
- Wei-Xiang Ma
- State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, Department of Pharmacology, School of Basic Medical Sciences, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Ping-Chuan Yuan
- Anhui Provincial Engineering Research Center for Polysaccharide Drugs, Provincial Engineering Laboratory for Screening and Re-evaluation of Active Compounds of Herbal Medicines in Southern Anhui, School of Pharmacy, Wannan Medical College, Wuhu, China
| | - Hui Zhang
- Anhui Provincial Engineering Research Center for Polysaccharide Drugs, Provincial Engineering Laboratory for Screening and Re-evaluation of Active Compounds of Herbal Medicines in Southern Anhui, School of Pharmacy, Wannan Medical College, Wuhu, China
| | - Ling-Xi Kong
- State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, Department of Pharmacology, School of Basic Medical Sciences, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Michael Lazarus
- International Institute for Integrative Sleep Medicine (WPI-IIIS) and Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Wei-Min Qu
- State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, Department of Pharmacology, School of Basic Medical Sciences, Institutes of Brain Science, Fudan University, Shanghai, China
- *Correspondence: Wei-Min Qu, ; Yi-Qun Wang, ; Zhi-Li Huang,
| | - Yi-Qun Wang
- State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, Department of Pharmacology, School of Basic Medical Sciences, Institutes of Brain Science, Fudan University, Shanghai, China
- *Correspondence: Wei-Min Qu, ; Yi-Qun Wang, ; Zhi-Li Huang,
| | - Zhi-Li Huang
- State Key Laboratory of Medical Neurobiology, MOE Frontiers Center for Brain Science, Department of Pharmacology, School of Basic Medical Sciences, Institutes of Brain Science, Fudan University, Shanghai, China
- *Correspondence: Wei-Min Qu, ; Yi-Qun Wang, ; Zhi-Li Huang,
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Carlson Z, Drew K. Characterization and Seasonal Modulation of Adenosine A 1 Receptors in the Arctic Ground Squirrel Brain. Int J Mol Sci 2023; 24:ijms24021598. [PMID: 36675112 PMCID: PMC9867220 DOI: 10.3390/ijms24021598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 01/07/2023] [Accepted: 01/08/2023] [Indexed: 01/15/2023] Open
Abstract
Hibernation is an adaptation that allows animals such as the Arctic ground squirrel (AGS) to survive the absence of food or water during the winter season. Understanding mechanisms of metabolic suppression during hibernation torpor promises new therapies for critical care. The activation of the Adenosine A1 receptor (A1AR) has been shown to be necessary and sufficient for entrance into hibernation with a winter season sensitization to the agonist, but the role of the A1AR in seasonal sensitization is unknown. In the current study, we characterize the A1AR in the forebrain, hippocampus and hypothalamus of summer and torpid AGS. For the first time, we define the pharmacological characteristics of the A1AR agonist, N6-cyclohexyladenosine and the A1AR antagonist dipropylcyclopentylxanthine (DPCPX) in the AGS brain. In addition, we test the hypothesis that increased A1AR agonist efficacy is responsible for sensitization of the A1AR during the torpor season. The resulting 35S-GTPγS binding data indicate an increase in agonist potency during torpor in two out of three brain regions. In addition to 35S-GTPγS binding, [3H]DPCPX saturation and competition assays establish for the first-time pharmacological characteristics for the A1AR agonist, N6-cyclohexyladenosine and the A1AR antagonist dipropylcyclopentylxanthine (DPCPX) in AGS brain.
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Affiliation(s)
- Zachary Carlson
- Institute of Arctic Biology, University of Alaska, Fairbanks, AK 99775, USA
| | - Kelly Drew
- Institute of Arctic Biology, University of Alaska, Fairbanks, AK 99775, USA
- Center for Transformative Research in Metabolism, University of Alaska, Fairbanks, AK 99775, USA
- Correspondence:
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Frare C, Drew KL. Seasonal changes in adenosine kinase in tanycytes of the Arctic ground squirrel (Urocitellus parryii). J Chem Neuroanat 2021; 113:101920. [PMID: 33515665 PMCID: PMC8091519 DOI: 10.1016/j.jchemneu.2021.101920] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 12/29/2020] [Accepted: 01/18/2021] [Indexed: 10/22/2022]
Abstract
Hibernation is a seasonal strategy to conserve energy, characterized by modified thermoregulation, an increase in sleep pressure and drastic metabolic changes. Glial cells such as astrocytes and tanycytes are the brain metabolic sensors, but it remains unknown whether they contribute to seasonal expression of hibernation. The onset of hibernation is controlled by an undefined endogenous circannual rhythm in which adenosine plays a role through the activation of the A1 adenosine receptor (A1AR). Seasonal changes in brain levels of adenosine may contribute to an increase in A1AR sensitivity leading to the onset of hibernation. The primary regulator of extracellular adenosine concentration is adenosine kinase, which is located in astrocytes. Using immunohistochemistry to localize and quantify adenosine kinase in Arctic ground squirrels' brain collected during different seasons, we report lower expression of adenosine kinase in the third ventricle tanycytes in winter compared to summer; a similar change was not seen in astrocytes. Moreover, for the first time, we describe adenosine kinase expression in tanycyte cell bodies in the hypothalamus and in the area postrema, both brain regions involved in energy homeostasis. Next we describe seasonal changes in tanycyte morphology in the hypothalamus. Although still speculative, our findings contribute to a model whereby adenosine kinase in tanycytes regulates seasonal changes in extracellular concentration of adenosine underling the seasonal expression of hibernation.
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Affiliation(s)
- C Frare
- Department of Chemistry and Biochemistry, University of Alaska Fairbanks, 900 Yukon Drive Rm. 194, Fairbanks, AK 99775-6160, USA; Institute of Arctic Biology, Center for Transformative Research in Metabolism, University of Alaska Fairbanks, 2140 Koyukuk Drive, Fairbanks, AK 99775-7000 USA
| | - K L Drew
- Department of Chemistry and Biochemistry, University of Alaska Fairbanks, 900 Yukon Drive Rm. 194, Fairbanks, AK 99775-6160, USA; Institute of Arctic Biology, Center for Transformative Research in Metabolism, University of Alaska Fairbanks, 2140 Koyukuk Drive, Fairbanks, AK 99775-7000 USA.
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7
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Bajgar A, Krejčová G, Doležal T. Polarization of Macrophages in Insects: Opening Gates for Immuno-Metabolic Research. Front Cell Dev Biol 2021; 9:629238. [PMID: 33659253 PMCID: PMC7917182 DOI: 10.3389/fcell.2021.629238] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Accepted: 01/11/2021] [Indexed: 12/14/2022] Open
Abstract
Insulin resistance and cachexia represent severe metabolic syndromes accompanying a variety of human pathological states, from life-threatening cancer and sepsis to chronic inflammatory states, such as obesity and autoimmune disorders. Although the origin of these metabolic syndromes has not been fully comprehended yet, a growing body of evidence indicates their possible interconnection with the acute and chronic activation of an innate immune response. Current progress in insect immuno-metabolic research reveals that the induction of insulin resistance might represent an adaptive mechanism during the acute phase of bacterial infection. In Drosophila, insulin resistance is induced by signaling factors released by bactericidal macrophages as a reflection of their metabolic polarization toward aerobic glycolysis. Such metabolic adaptation enables them to combat the invading pathogens efficiently but also makes them highly nutritionally demanding. Therefore, systemic metabolism has to be adjusted upon macrophage activation to provide them with nutrients and thus support the immune function. That anticipates the involvement of macrophage-derived systemic factors mediating the inter-organ signaling between macrophages and central energy-storing organs. Although it is crucial to coordinate the macrophage cellular metabolism with systemic metabolic changes during the acute phase of bacterial infection, the action of macrophage-derived factors may become maladaptive if chronic or in case of infection by an intracellular pathogen. We hypothesize that insulin resistance evoked by macrophage-derived signaling factors represents an adaptive mechanism for the mobilization of sources and their preferential delivery toward the activated immune system. We consider here the validity of the presented model for mammals and human medicine. The adoption of aerobic glycolysis by bactericidal macrophages as well as the induction of insulin resistance by macrophage-derived factors are conserved between insects and mammals. Chronic insulin resistance is at the base of many human metabolically conditioned diseases such as non-alcoholic steatohepatitis, atherosclerosis, diabetes, and cachexia. Therefore, revealing the original biological relevance of cytokine-induced insulin resistance may help to develop a suitable strategy for treating these frequent diseases.
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Affiliation(s)
- Adam Bajgar
- Department of Molecular Biology and Genetics, University of South Bohemia, Ceske Budejovice, Czechia
| | - Gabriela Krejčová
- Department of Molecular Biology and Genetics, University of South Bohemia, Ceske Budejovice, Czechia
| | - Tomáš Doležal
- Department of Molecular Biology and Genetics, University of South Bohemia, Ceske Budejovice, Czechia
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Xie LH, Gwathmey JK, Zhao Z. Cardiac adaptation and cardioprotection against arrhythmias and ischemia-reperfusion injury in mammalian hibernators. Pflugers Arch 2021; 473:407-416. [PMID: 33394082 DOI: 10.1007/s00424-020-02511-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 12/04/2020] [Accepted: 12/23/2020] [Indexed: 12/15/2022]
Abstract
Hibernation allows animals to enter an energy conserving state to survive severe drops in external temperatures and a shortage of food. It has been observed that the hearts of mammalian hibernators exhibit intrinsic protection against ischemia-reperfusion (I/R) injury and cardiac arrhythmias in the winter whether they are hibernating or not. However, the molecular and ionic mechanisms for cardioprotection in mammalian hibernators remain elusive. Recent studies in woodchucks (Marmota monax) have suggested that cardiac adaptation occurs at different levels and mediates an intrinsic cardioprotection prior to/in the winter. The molecular/cellular remodeling in the winter (with or without hibernation) includes (1) an upregulation of transcriptional factor, anti-apoptotic factor, nitric oxide synthase, protein kinase C-ε, and phosphatidylinositol-4,5-bisphosphate 3-kinase; (2) an upregulation of antioxidant enzymes (e.g. superoxide dismutase and catalase); (3) a reduction in the oxidation level of Ca2+/calmodulin-dependent protein kinase II (CaMKII); and (4) alterations in the expression and activity of multiple ion channels/transporters. Therefore, the cardioprotection against I/R injury in the winter is most likely mediated by enhancement in signaling pathways that are shared by preconditioning, reduced cell apoptosis, and increased detoxification of reactive oxygen species (ROS). The resistance to cardiac arrhythmias and sudden cardiac death in the winter is closely associated with an upregulation of the antioxidant catalase and a downregulation of CaMKII activation. This remodeling of the heart is associated with a reduction in the incidence of afterdepolarizations and triggered activities. In this short review article, we will discuss the seasonal changes in gene and protein expression profiles as well as alterations in the function of key proteins that are associated with the occurrence of cardioprotection against myocardial damage from ischemic events and fatal arrhythmias in a mammalian hibernator. Understanding the intrinsic cardiac adaptive mechanisms that confer cardioprotection in hibernators may offer new strategies to protect non-hibernating animals, especially humans, from I/R injury and ischemia-induced fatal cardiac arrhythmias.
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Affiliation(s)
- Lai-Hua Xie
- Department of Cell Biology and Molecular Medicine, Rutgers-New Jersey Medical School, Newark, NJ, 07103, USA.
| | - Judith K Gwathmey
- Department of Cell Biology and Molecular Medicine, Rutgers-New Jersey Medical School, Newark, NJ, 07103, USA
| | - Zhenghang Zhao
- Department of Pharmacology, School of Medicine, Xi'an Jiaotong University, Xi'an, 710061, China
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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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10
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Chayama Y, Ando L, Sato Y, Shigenobu S, Anegawa D, Fujimoto T, Taii H, Tamura Y, Miura M, Yamaguchi Y. Molecular Basis of White Adipose Tissue Remodeling That Precedes and Coincides With Hibernation in the Syrian Hamster, a Food-Storing Hibernator. Front Physiol 2019; 9:1973. [PMID: 30745884 PMCID: PMC6360343 DOI: 10.3389/fphys.2018.01973] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2018] [Accepted: 12/31/2018] [Indexed: 12/31/2022] Open
Abstract
Mammalian hibernators store fat extensively in white adipose tissues (WATs) during pre-hibernation period (Pre-HIB) to prepare for hibernation. However, the molecular mechanisms underlying the pre-hibernation remodeling of WAT have not been fully elucidated. Syrian hamsters, a food-storing hibernator, can hibernate when exposed to a winter-like short day photoperiod and cold ambient temperature (SD-Cold). Animals subjected to prolonged SD-Cold had smaller white adipocytes and beige-like cells within subcutaneous inguinal WAT (iWAT). Time-course analysis of gene expression with RNA-sequencing and quantitative PCR demonstrated that the mRNA expression of not only genes involved in lipid catabolism (lipolysis and beta-oxidation) but also lipid anabolism (lipogenesis and lipid desaturation) was simultaneously up-regulated prior to hibernation onset in the animals. The enhanced capacity of both lipid catabolism and lipid anabolism during hibernation period (HIB) is striking contrast to previous observations in fat-storing hibernators that only enhance catabolism during HIB. The mRNA expression of mTORC1 and PPAR signaling molecules increased, and pharmacological activation of PPARs indeed up-regulated lipid metabolism genes in iWAT explants from Syrian hamsters. These results suggest that the Syrian hamster rewires lipid metabolisms while preparing for hibernation to effectively utilize body fat and synthesize it from food intake during HIB.
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Affiliation(s)
- Yuichi Chayama
- Department of Genetics, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Lisa Ando
- Department of Genetics, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Yuya Sato
- Department of Genetics, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Shuji Shigenobu
- Functional Genomics Facility, National Institute for Basic Biology, Okazaki, Japan
| | - Daisuke Anegawa
- Department of Genetics, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Takayuki Fujimoto
- Department of Genetics, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Hiroki Taii
- Department of Genetics, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Yutaka Tamura
- Department of Pharmacology, Faculty of Pharmacy and Pharmaceutical Sciences, Fukuyama University, Fukuyama, Japan
| | - Masayuki Miura
- Department of Genetics, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Yoshifumi Yamaguchi
- Department of Genetics, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan.,Hibernation Metabolism, Physiology and Development Group, Institute of Low Temperature Science, Hokkaido University, Sapporo, Japan
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11
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Andrews MT. Molecular interactions underpinning the phenotype of hibernation in mammals. J Exp Biol 2019; 222:222/2/jeb160606. [DOI: 10.1242/jeb.160606] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
ABSTRACT
Mammals maintain a constant warm body temperature, facilitating a wide variety of metabolic reactions. Mammals that hibernate have the ability to slow their metabolism, which in turn reduces their body temperature and leads to a state of hypothermic torpor. For this metabolic rate reduction to occur on a whole-body scale, molecular interactions that change the physiology of cells, tissues and organs are required, resulting in a major departure from normal mammalian homeostasis. The aim of this Review is to cover recent advances in the molecular biology of mammalian hibernation, including the role of small molecules, seasonal changes in gene expression, cold-inducible RNA-binding proteins, the somatosensory system and emerging information on hibernating primates. To underscore the importance of differential gene expression across the hibernation cycle, mRNA levels for 14,261 ground squirrel genes during periods of activity and torpor are made available for several tissues via an interactive transcriptome browser. This Review also addresses recent findings on molecular interactions responsible for multi-day survival of near-freezing body temperatures, single-digit heart rates and a slowed metabolism that greatly reduces oxygen consumption. A better understanding of how natural hibernators survive these physiological extremes is beginning to lead to innovations in human medicine.
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Affiliation(s)
- Matthew T. Andrews
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR 97331, USA
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12
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Frare C, Jenkins ME, Soldin SJ, Drew KL. The Raphe Pallidus and the Hypothalamic-Pituitary-Thyroid Axis Gate Seasonal Changes in Thermoregulation in the Hibernating Arctic Ground Squirrel ( Urocitellus parryii). Front Physiol 2018; 9:1747. [PMID: 30618783 PMCID: PMC6299024 DOI: 10.3389/fphys.2018.01747] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Accepted: 11/20/2018] [Indexed: 01/17/2023] Open
Abstract
Thermoregulation is necessary to maintain energy homeostasis. The novel discovery of brown adipose tissue (BAT) in humans has increased research interests in better understanding BAT thermogenesis to restore energy balance in metabolic disorders. The hibernating Arctic ground squirrel (AGS) offers a novel approach to investigate BAT thermogenesis. AGS seasonally increase their BAT mass to increase the ability to generate heat during interbout arousals. The mechanisms promoting the seasonal changes in BAT thermogenesis are not well understood. BAT thermogenesis is regulated by the raphe pallidus (rPA) and by thyroid hormones produced by the hypothalamic–pituitary–thyroid (HPT) axis. Here, we investigate if the HPT axis and the rPA undergo seasonal changes to modulate BAT thermogenesis in hibernation. We used histological analysis and tandem mass spectrometry to assess activation of the HPT axis and immunohistochemistry to measure neuronal activation. We found an increase in HPT axis activation in fall and in response to pharmacologically induced torpor when adenosine A1 receptor agonist was administered in winter. By contrast, the rPA neuronal activation was lower in winter in response to pharmacologically induced torpor. Activation of the rPA was also lower in winter compared to the other seasons. Our results suggest that thermogenic capacity develops during fall as the HPT axis is activated to reach maximum capacity in winter seen by increased free thyroid hormones in response to cooling. However, thermogenesis is inhibited during torpor as sympathetic premotor neuronal activation is lower in winter, until arousal when inhibition of thermogenesis is relieved. These findings describe seasonal modulation of thermoregulation that conserves energy through attenuated sympathetic drive, but retains heat generating capacity through activation of the HPT axis.
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Affiliation(s)
- Carla Frare
- Department of Chemistry and Biochemistry, University of Alaska Fairbanks, Fairbanks, AK, United States.,Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK, United States
| | - Mackenzie E Jenkins
- Department of Chemistry and Biochemistry, University of Alaska Fairbanks, Fairbanks, AK, United States
| | - Steven J Soldin
- National Institutes of Health Clinical Center, Bethesda, MD, United States.,Division of Endocrinology and Metabolism, Department of Medicine, Georgetown University, Washington, DC, United States
| | - Kelly L Drew
- Department of Chemistry and Biochemistry, University of Alaska Fairbanks, Fairbanks, AK, United States.,Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK, United States
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13
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Oliver SR, Anderson KJ, Hunstiger MM, Andrews MT. Turning down the heat: Down-regulation of sarcolipin in a hibernating mammal. Neurosci Lett 2018; 696:13-19. [PMID: 30528880 DOI: 10.1016/j.neulet.2018.11.059] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 11/30/2018] [Accepted: 11/30/2018] [Indexed: 02/01/2023]
Abstract
Hibernation in mammals is a whole-body phenotype that involves profound reductions in oxygen consumption, metabolic reactions, core body temperature, neural activity and heart rate. An important aspect of mammalian hibernation is the ability to reverse this state of hypothermic torpor by rewarming and subsequent arousal. Brown adipose tissue (BAT) and skeletal muscle shivering have been characterized as the predominant driving forces for thermogenesis during arousal. Conversely, the thermogenic contribution of these organs needs to be minimized as hibernating mammals enter torpor. Because skeletal muscle accounts for approximately 40% of the dry mass of the typical mammalian body, we aim to broaden the spotlight to include the importance of down-regulating skeletal muscle non-shivering thermogenesis during hibernation to allow for whole-body cooling and long-term maintenance of a depressed core body temperature when the animal is in torpor. This minireview will briefly describe the current understanding of thermoregulation in hibernating mammals and present new preliminary data on the importance of skeletal muscle and the micro-peptide sarcolipin as a major thermogenic target.
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Affiliation(s)
- S Ryan Oliver
- Department of Chemistry and Biochemistry, University of Alaska Fairbanks, Fairbanks, AK 99775, USA.
| | - Kyle J Anderson
- Department of Biomedical Sciences, University of Minnesota Medical School Duluth, Duluth, MN 55812, USA.
| | - Moriah M Hunstiger
- Department of Chemistry and Biochemistry, University of Alaska Fairbanks, Fairbanks, AK 99775, USA.
| | - Matthew T Andrews
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR 97331, USA.
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14
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Kronfeld-Schor N, Visser ME, Salis L, van Gils JA. Chronobiology of interspecific interactions in a changing world. Philos Trans R Soc Lond B Biol Sci 2018; 372:rstb.2016.0248. [PMID: 28993492 DOI: 10.1098/rstb.2016.0248] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/20/2017] [Indexed: 01/10/2023] Open
Abstract
Animals should time activities, such as foraging, migration and reproduction, as well as seasonal physiological adaptation, in a way that maximizes fitness. The fitness outcome of such activities depends largely on their interspecific interactions; the temporal overlap with other species determines when they should be active in order to maximize their encounters with food and to minimize their encounters with predators, competitors and parasites. To cope with the constantly changing, but predictable structure of the environment, organisms have evolved internal biological clocks, which are synchronized mainly by light, the most predictable and reliable environmental cue (but which can be masked by other variables), which enable them to anticipate and prepare for predicted changes in the timing of the species they interact with, on top of responding to them directly. Here, we review examples where the internal timing system is used to predict interspecific interactions, and how these interactions affect the internal timing system and activity patterns. We then ask how plastic these mechanisms are, how this plasticity differs between and within species and how this variability in plasticity affects interspecific interactions in a changing world, in which light, the major synchronizer of the biological clock, is no longer a reliable cue owing to the rapidly changing climate, the use of artificial light and urbanization.This article is part of the themed issue 'Wild clocks: integrating chronobiology and ecology to understand timekeeping in free-living animals'.
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Affiliation(s)
| | - Marcel E Visser
- Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), PO 50, Wageningen 6700 AB, The Netherlands
| | - Lucia Salis
- Department of Animal Ecology, Netherlands Institute of Ecology (NIOO-KNAW), PO 50, Wageningen 6700 AB, The Netherlands
| | - Jan A van Gils
- Department of Coastal Systems, NIOZ Royal Netherlands Institute for Sea Research, and Utrecht University, PO Box 59, Den Burg 1790 AB, The Netherlands
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15
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Abstract
Several physiological functions of adenosine (Ado) appear to be mediated by four G protein-coupled Ado receptors. Ado is produced extracellularly from the catabolism of the excreted ATP, or intracellularly from AMP, and then released through its transporter. High level of intracellular Ado occurs only at low energy charge, as an intermediate of ATP breakdown, leading to hypoxanthine production. AMP, the direct precursor of Ado, is now considered as an important stress signal inside cell triggering metabolic regulation through activation of a specific AMP-dependent protein kinase. Intracellular Ado produced from AMP by allosterically regulated nucleotidases can be regarded as a stress signal as well. To study the receptor-independent effects of Ado, several experimental approaches have been proposed, such as inhibition or silencing of key enzymes of Ado metabolism, knockdown of Ado receptors in animals, the use of antagonists, or cell treatment with deoxyadenosine, which is substrate of the enzymes acting on Ado, but is unable to interact with Ado receptors. In this way, it was demonstrated that, among other functions, intracellular Ado modulates angiogenesis by regulating promoter methylation, induces hypothermia, promotes apoptosis in sympathetic neurons, and, in the case of oxygen and glucose deprivation, exerts a cytoprotective effect by replenishing the ATP pool.
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16
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Bailey IR, Laughlin B, Moore LA, Bogren LK, Barati Z, Drew KL. Optimization of Thermolytic Response to A 1 Adenosine Receptor Agonists in Rats. J Pharmacol Exp Ther 2017; 362:424-430. [PMID: 28652388 DOI: 10.1124/jpet.117.241315] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Accepted: 06/22/2017] [Indexed: 12/13/2022] Open
Abstract
Cardiac arrest is a leading cause of death in the United States, and, currently, therapeutic hypothermia, now called targeted temperature management (TTM), is the only recent treatment modality proven to increase survival rates and reduce morbidity for this condition. Shivering and subsequent metabolic stress, however, limit application and benefit of TTM. Stimulating central nervous system A1 adenosine receptors (A1AR) inhibits shivering and nonshivering thermogenesis in rats and induces a hibernation-like response in hibernating species. In this study, we investigated the pharmacodynamics of two A1AR agonists in development as antishivering agents. To optimize body temperature (Tb) control, we evaluated the influence of every-other-day feeding, dose, drug, and ambient temperature (Ta) on the Tb-lowering effects of N6-cyclohexyladenosine (CHA) and the partial A1AR agonist capadenoson in rats. The highest dose of CHA (1.0 mg/kg, i.p.) caused all ad libitum-fed animals tested to reach our target Tb of 32°C, but responses varied and some rats overcooled to a Tb as low as 21°C at 17.0°C Ta Dietary restriction normalized the response to CHA. The partial agonist capadenoson (1.0 or 2.0 mg/kg, i.p.) produced a more consistent response, but the highest dose decreased Tb by only 1.6°C. To prevent overcooling after CHA, we studied continuous i.v. administration in combination with dynamic surface temperature control. Results show that after CHA administration control of surface temperature maintains desired target Tb better than dose or ambient temperature.
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Affiliation(s)
- Isaac R Bailey
- Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, Alaska (I.R.B., B.L., L.A.M., L.K.B., Z.B., K.L.D.); and Departments of Chemistry and Biochemisty, University of Alaska Fairbanks, Fairbanks, Alaska (I.R.B., B.L., K.L.D.)
| | - Bernard Laughlin
- Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, Alaska (I.R.B., B.L., L.A.M., L.K.B., Z.B., K.L.D.); and Departments of Chemistry and Biochemisty, University of Alaska Fairbanks, Fairbanks, Alaska (I.R.B., B.L., K.L.D.)
| | - Lucille A Moore
- Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, Alaska (I.R.B., B.L., L.A.M., L.K.B., Z.B., K.L.D.); and Departments of Chemistry and Biochemisty, University of Alaska Fairbanks, Fairbanks, Alaska (I.R.B., B.L., K.L.D.)
| | - Lori K Bogren
- Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, Alaska (I.R.B., B.L., L.A.M., L.K.B., Z.B., K.L.D.); and Departments of Chemistry and Biochemisty, University of Alaska Fairbanks, Fairbanks, Alaska (I.R.B., B.L., K.L.D.)
| | - Zeinab Barati
- Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, Alaska (I.R.B., B.L., L.A.M., L.K.B., Z.B., K.L.D.); and Departments of Chemistry and Biochemisty, University of Alaska Fairbanks, Fairbanks, Alaska (I.R.B., B.L., K.L.D.)
| | - Kelly L Drew
- Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, Alaska (I.R.B., B.L., L.A.M., L.K.B., Z.B., K.L.D.); and Departments of Chemistry and Biochemisty, University of Alaska Fairbanks, Fairbanks, Alaska (I.R.B., B.L., K.L.D.)
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17
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Bhowmick S, Moore JT, Kirschner DL, Drew KL. Arctic ground squirrel hippocampus tolerates oxygen glucose deprivation independent of hibernation season even when not hibernating and after ATP depletion, acidosis, and glutamate efflux. J Neurochem 2017; 142:160-170. [PMID: 28222226 DOI: 10.1111/jnc.13996] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Revised: 01/16/2017] [Accepted: 02/08/2017] [Indexed: 12/20/2022]
Abstract
Cerebral ischemia/reperfusion (I/R) triggers a cascade of uncontrolled cellular processes that perturb cell homeostasis. The arctic ground squirrel (AGS), a seasonal hibernator resists brain damage following cerebral I/R caused by cardiac arrest and resuscitation. However, it remains unclear if tolerance to I/R injury in AGS depends on the hibernation season. Moreover, it is also not clear if events such as depletion of ATP, acidosis, and glutamate efflux that are associated with anoxic depolarization are attenuated in AGS. Here, we employ a novel microperfusion technique to test the hypothesis that tolerance to I/R injury modeled in an acute hippocampal slice preparation in AGS is independent of the hibernation season and persists even after glutamate efflux. Acute hippocampal slices were harvested from summer euthermic AGS, hibernating AGS, and interbout euthermic AGS. Slices were subjected to oxygen glucose deprivation (OGD), an in vitro model of I/R injury to determine cell death marked by lactate dehydrogenase (LDH) release. ATP was assayed using ENLITEN ATP assay. Glutamate and aspartate efflux was measured using capillary electrophoresis. For acidosis, slices were subjected to pH 6.4 or ischemic shift solution (ISS). Acute hippocampal slices from rats were used as a positive control, susceptible to I/R injury. Our results indicate that when tissue temperature is maintained at 36°C, hibernation season has no influence on OGD-induced cell death in AGS hippocampal slices. Our data also show that tolerance to OGD in AGS hippocampal slices occurs despite loss of ATP and glutamate release, and persists during conditions that mimic acidosis and ionic shifts, characteristic of cerebral I/R. Read the Editorial Comment for this article on page 10.
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Affiliation(s)
- Saurav Bhowmick
- Department of Chemistry and Biochemistry, University of Alaska Fairbanks, Fairbanks, Alaska, USA.,Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, Alaska, USA
| | - Jeanette T Moore
- Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, Alaska, USA
| | - Daniel L Kirschner
- Department of Chemistry and Biochemistry, University of Alaska Fairbanks, Fairbanks, Alaska, USA
| | - Kelly L Drew
- Department of Chemistry and Biochemistry, University of Alaska Fairbanks, Fairbanks, Alaska, USA.,Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, Alaska, USA
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18
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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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19
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Carlin JL, Jain S, Gizewski E, Wan TC, Tosh DK, Xiao C, Auchampach JA, Jacobson KA, Gavrilova O, Reitman ML. Hypothermia in mouse is caused by adenosine A 1 and A 3 receptor agonists and AMP via three distinct mechanisms. Neuropharmacology 2017; 114:101-113. [PMID: 27914963 PMCID: PMC5183552 DOI: 10.1016/j.neuropharm.2016.11.026] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Revised: 11/02/2016] [Accepted: 11/28/2016] [Indexed: 10/20/2022]
Abstract
Small mammals have the ability to enter torpor, a hypothermic, hypometabolic state, allowing impressive energy conservation. Administration of adenosine or adenosine 5'-monophosphate (AMP) can trigger a hypothermic, torpor-like state. We investigated the mechanisms for hypothermia using telemetric monitoring of body temperature in wild type and receptor knock out (Adora1-/-, Adora3-/-) mice. Confirming prior data, stimulation of the A3 adenosine receptor (AR) induced hypothermia via peripheral mast cell degranulation, histamine release, and activation of central histamine H1 receptors. In contrast, A1AR agonists and AMP both acted centrally to cause hypothermia. Commonly used, selective A1AR agonists, including N6-cyclopentyladenosine (CPA), N6-cyclohexyladenosine (CHA), and MRS5474, caused hypothermia via both A1AR and A3AR when given intraperitoneally. Intracerebroventricular dosing, low peripheral doses of Cl-ENBA [(±)-5'-chloro-5'-deoxy-N6-endo-norbornyladenosine], or using Adora3-/- mice allowed selective stimulation of A1AR. AMP-stimulated hypothermia can occur independently of A1AR, A3AR, and mast cells. A1AR and A3AR agonists and AMP cause regulated hypothermia that was characterized by a drop in total energy expenditure, physical inactivity, and preference for cooler environmental temperatures, indicating a reduced body temperature set point. Neither A1AR nor A3AR was required for fasting-induced torpor. A1AR and A3AR agonists and AMP trigger regulated hypothermia via three distinct mechanisms.
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Affiliation(s)
- Jesse Lea Carlin
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD 20892, USA
| | - Shalini Jain
- Mouse Metabolism Core, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD 20892, USA
| | - Elizabeth Gizewski
- Department of Pharmacology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
| | - Tina C Wan
- Department of Pharmacology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
| | - Dilip K Tosh
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD 20892, USA
| | - Cuiying Xiao
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD 20892, USA
| | - John A Auchampach
- Department of Pharmacology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
| | - Kenneth A Jacobson
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD 20892, USA
| | - Oksana Gavrilova
- Mouse Metabolism Core, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD 20892, USA
| | - Marc L Reitman
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD 20892, USA.
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20
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Drew KL, Frare C, Rice SA. Neural Signaling Metabolites May Modulate Energy Use in Hibernation. Neurochem Res 2017; 42:141-150. [PMID: 27878659 PMCID: PMC5284051 DOI: 10.1007/s11064-016-2109-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 10/05/2016] [Accepted: 11/11/2016] [Indexed: 12/23/2022]
Abstract
Despite an epidemic in obesity and metabolic syndrome limited means exist to effect adiposity or metabolic rate other than life style changes. Here we review evidence that neural signaling metabolites may modulate thermoregulatory pathways and offer novel means to fine tune energy use. We extend prior reviews on mechanisms that regulate thermogenesis and energy use in hibernation by focusing primarily on the neural signaling metabolites adenosine, AMP and glutamate.
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Affiliation(s)
- Kelly L Drew
- Department of Chemistry and Biochemistry, Institute of Arctic Biology, University of Alaska Fairbanks, 902 N. Koyukuk Drive, Fairbanks, AK, 99775, USA.
| | - Carla Frare
- Department of Chemistry and Biochemistry, Institute of Arctic Biology, University of Alaska Fairbanks, 902 N. Koyukuk Drive, Fairbanks, AK, 99775, USA
| | - Sarah A Rice
- Department of Chemistry and Biochemistry, Institute of Arctic Biology, University of Alaska Fairbanks, 902 N. Koyukuk Drive, Fairbanks, AK, 99775, USA
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21
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Pamenter ME, Dzal YA, Milsom WK. Adenosine receptors mediate the hypoxic ventilatory response but not the hypoxic metabolic response in the naked mole rat during acute hypoxia. Proc Biol Sci 2016; 282:20141722. [PMID: 25520355 DOI: 10.1098/rspb.2014.1722] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Naked mole rats are the most hypoxia-tolerant mammals identified; however, the mechanisms underlying this tolerance are poorly understood. Using whole-animal plethysmography and open-flow respirometry, we examined the hypoxic metabolic response (HMR), hypoxic ventilatory response (HVR) and hypoxic thermal response in awake, freely behaving naked mole rats exposed to 7% O₂ for 1 h. Metabolic rate and ventilation each reversibly decreased 70% in hypoxia (from 39.6 ± 2.9 to 12.1 ± 0.3 ml O₂ min(-1) kg(-1), and 1412 ± 244 to 417 ± 62 ml min(-1) kg(-1), respectively; p < 0.05), whereas body temperature was unchanged and animals remained awake and active. Subcutaneous injection of the general adenosine receptor antagonist aminophylline (AMP; 100 mg kg(-1), in saline), but not control saline injections, prevented the HVR but had no effect on the HMR. As a result, AMP-treated naked mole rats exhibited extreme hyperventilation in hypoxia. These animals were also less tolerant to hypoxia, and in some cases hypoxia was lethal following AMP injection. We conclude that in naked mole rats (i) hypoxia tolerance is partially dependent on profound hypoxic metabolic and ventilatory responses, which are equal in magnitude but occur independently of thermal changes in hypoxia, and (ii) adenosine receptors mediate the HVR but not the HMR.
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Affiliation(s)
- Matthew E Pamenter
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4
| | - Yvonne A Dzal
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4
| | - William K Milsom
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4
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22
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Dirkes MC, van Gulik TM, Heger M. The physiology of artificial hibernation. J Clin Transl Res 2015; 1:78-93. [PMID: 30873448 PMCID: PMC6410623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Revised: 09/07/2015] [Accepted: 09/14/2015] [Indexed: 11/18/2022] Open
Abstract
Incomplete understanding of the mechanisms responsible for induction of hibernation prevent translation of natural hibernation to its artificial counterpart. To facilitate this translation, a model was developed that identifies the necessary physiological changes for induction of artificial hibernation. This model encompasses six essential components: metabolism (anabolism and catabolism), body temperature, thermoneutral zone, substrate, ambient temperature, and hibernation-inducing agents. The individual components are interrelated and collectively govern the induction and sustenance of a hypometabolic state. To illustrate the potential validity of this model, various pharmacological agents (hibernation induction trigger, delta-opioid, hydrogen sulfide, 5'-adenosine monophosphate, thyronamine, 2-deoxyglucose, magnesium) are described in terms of their influence on specific components of the model and corollary effects on metabolism. Relevance for patients: The ultimate purpose of this model is to help expand the paradigm regarding the mechanisms of hibernation from a physiological perspective and to assist in translating this natural phenomenon to the clinical setting.
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23
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Jinka TR, Combs VM, Drew KL. Translating drug-induced hibernation to therapeutic hypothermia. ACS Chem Neurosci 2015; 6:899-904. [PMID: 25812681 DOI: 10.1021/acschemneuro.5b00056] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Therapeutic hypothermia (TH) improves prognosis after cardiac arrest; however, thermoregulatory responses such as shivering complicate cooling. Hibernators exhibit a profound and safe reversible hypothermia without any cardiovascular side effects by lowering the shivering threshold at low ambient temperatures (Ta). Activation of adenosine A1 receptors (A1ARs) in the central nervous system (CNS) induces hibernation in hibernating species and a hibernation-like state in rats, principally by attenuating thermogenesis. Thus, we tested the hypothesis that targeted activation of the central A1AR combined with a lower Ta would provide a means of managing core body temperature (Tb) below 37 °C for therapeutic purposes. We targeted the A1AR within the CNS by combining systemic delivery of the A1AR agonist (6)N-cyclohexyladenosine (CHA) with 8-(p-sulfophenyl)theophylline (8-SPT), a nonspecific adenosine receptor antagonist that does not readily cross the blood-brain barrier. Results show that CHA (1 mg/kg) and 8-SPT (25 mg/kg), administered intraperitoneally every 4 h for 20 h at a Ta of 16 °C, induce and maintain the Tb between 29 and 31 °C for 24 h in both naïve rats and rats subjected to asphyxial cardiac arrest for 8 min. Faster and more stable hypothermia was achieved by continuous infusion of CHA delivered subcutaneously via minipumps. Animals subjected to cardiac arrest and cooled by CHA survived better and showed less neuronal cell death than normothermic control animals. Central A1AR activation in combination with a thermal gradient shows promise as a novel and effective pharmacological adjunct for inducing safe and reversible targeted temperature management.
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Affiliation(s)
- Tulasi R. Jinka
- University of Alaska Fairbanks, 902 North Koyukuk Drive, Fairbanks, Alaska 99775-7000, United States
- University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Velva M. Combs
- University of Alaska Fairbanks, 902 North Koyukuk Drive, Fairbanks, Alaska 99775-7000, United States
| | - Kelly L. Drew
- University of Alaska Fairbanks, 902 North Koyukuk Drive, Fairbanks, Alaska 99775-7000, United States
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Drew KL, Romanovsky AA, Stephen TKL, Tupone D, Williams RH. Future approaches to therapeutic hypothermia: a symposium report. Temperature (Austin) 2015; 2:168-71. [PMID: 27227020 PMCID: PMC4843898 DOI: 10.4161/23328940.2014.976512] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Revised: 10/09/2014] [Accepted: 10/09/2014] [Indexed: 12/22/2022] Open
Key Words
- A1AR
- AGS, arctic ground squirrel
- CE, capillary electrophoresis
- EEG,electroencephalogram
- FSCV, Fast scan cyclic voltammetry
- HPLC, high performance liquid chromatography
- ICV, intracerebroventricular
- TRPM8
- Tb, core body temperature
- adenosine
- capillary electrophoresis
- hibernation
- nNOS, neuronal nitric oxide synthase; NTS, nucleus tractus solitarii; TH, therapeutic hypothermia; TRP, transient receptor potential [channel(s)]; TRPM8, TRP melastatin-8
- nNOS/NK1
- targeted temperature management
- therapeutic hypothermia
- torpor
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Affiliation(s)
- Kelly L Drew
- Institute of Arctic Biology; University of Alaska Fairbanks; Fairbanks, AK, USA
| | - Andrej A Romanovsky
- Systemic Inflammation Laboratory (Fever Lab); Trauma Research, St. Joseph's Hospital and Medical Center; Phoenix, AZ, USA
| | - Terilyn KL Stephen
- Department of Chemistry and Biochemistry; University of Alaska Fairbanks; Fairbanks, AK, USA
| | - Domenico Tupone
- Department of Neurological Surgery; Oregon Health & Science University; Portland, OR, USA
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Schwartz C, Hampton M, Andrews MT. Hypothalamic gene expression underlying pre-hibernation satiety. GENES BRAIN AND BEHAVIOR 2015; 14:310-8. [PMID: 25640202 DOI: 10.1111/gbb.12199] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 12/16/2014] [Accepted: 12/22/2014] [Indexed: 11/30/2022]
Abstract
Prior to hibernation, 13-lined ground squirrels (Ictidomys tridecemlineatus) enter a hypophagic period where food consumption drops by an average of 55% in 3 weeks. This occurs naturally, while the ground squirrels are in constant environmental conditions and have free access to food. Importantly, this transition occurs before exposure to hibernation conditions (5°C and constant darkness), so the ground squirrels are still maintaining a moderate level of activity. In this study, we used the Illumina HiSeq 2000 system to sequence the hypothalamic transcriptomes of ground squirrels before and after the autumn feeding transition to examine the genes underlying this extreme change in feeding behavior. The hypothalamus was chosen because it is known to play a role in the control and regulation of food intake and satiety. Overall, our analysis identified 143 genes that are significantly differentially expressed between the two groups. Specifically, we found five genes associated with feeding behavior and obesity (VGF, TRH, LEPR, ADIPOR2, IRS2) that are all upregulated during the hypophagic period, after the feeding transition has occurred. We also found that serum leptin significantly increases in the hypophagic group. Several of the genes associated with the natural autumnal feeding decline in 13-lined ground squirrels show parallels to signaling pathways known to be disrupted in human metabolic diseases, like obesity and diabetes. In addition, many other genes were identified that could be important for the control of food consumption in other animals, including humans.
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Affiliation(s)
- C Schwartz
- Department of Biology, University of Minnesota Duluth, Duluth, MN, USA
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Christian SL, Rasley BT, Roe T, Moore JT, Harris MB, Drew KL. Habituation of Arctic ground squirrels (Urocitellus parryii) to handling and movement during torpor to prevent artificial arousal. Front Physiol 2014; 5:174. [PMID: 24847278 PMCID: PMC4023073 DOI: 10.3389/fphys.2014.00174] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Accepted: 04/15/2014] [Indexed: 11/13/2022] Open
Abstract
Hibernation is a unique physiological adaptation characterized by periods of torpor that consist of repeated, reversible, and dramatic reductions of body temperature, metabolism, and blood flow. External and internal triggers can induce arousal from torpor in the hibernator. Studies of hibernating animals often require that animals be handled or moved prior to sampling or euthanasia but this movement can induce changes in the hibernation status of the animal. In fact, it has been demonstrated that movement of animals while they are hibernating is sufficient to induce an artificial arousal, which can detrimentally alter experimental findings obtained from animals assumed to be torpid. Therefore, we assessed a method to induce habituation of torpid hibernators to handling and movement to reduce inadvertent arousals. A platform rocker was used to mimic motion experienced during transfer of an animal and changes in respiratory rate (RR) were used to assess responsiveness of torpid Arctic ground squirrels (AGS, Urocitellus parryii). We found that movement alone did not induce a change in RR, however, exposure to handling induced an increase in RR in almost all AGS. This change in RR was markedly reduced with increased exposures, and all AGS exhibited a change in RR ≤ 1 by the end of the study. AGS habituated faster mid-season compared to early in the season, which mirrors other assessments of seasonal variation of torpor depth. However, AGS regained responsiveness when they were not exposed to daily handling. While AGS continued to undergo natural arousals during the study, occurrence of a full arousal was neither necessary for becoming habituated nor detrimental to the time required for habituation. These data suggest that even when torpid, AGS are able to undergo mechanosensory habituation, one of the simplest forms of learning, and provides a reliable way to reduce the sensitivity of torpid animals to handling.
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Affiliation(s)
- Sherri L Christian
- Department of Chemistry and Biochemistry, Alaska Basic Neuroscience Program, Institute of Arctic Biology, University of Alaska Fairbanks Fairbanks, AK, USA ; Department of Biochemistry, Memorial University of Newfoundland St. John's, NL, Canada
| | - Brian T Rasley
- Department of Chemistry and Biochemistry, Alaska Basic Neuroscience Program, Institute of Arctic Biology, University of Alaska Fairbanks Fairbanks, AK, USA
| | - Tanna Roe
- Department of Chemistry and Biochemistry, Alaska Basic Neuroscience Program, Institute of Arctic Biology, University of Alaska Fairbanks Fairbanks, AK, USA
| | - Jeanette T Moore
- Department of Chemistry and Biochemistry, Alaska Basic Neuroscience Program, Institute of Arctic Biology, University of Alaska Fairbanks Fairbanks, AK, USA
| | - Michael B Harris
- Department of Chemistry and Biochemistry, Alaska Basic Neuroscience Program, Institute of Arctic Biology, University of Alaska Fairbanks Fairbanks, AK, USA
| | - Kelly L Drew
- Department of Chemistry and Biochemistry, Alaska Basic Neuroscience Program, Institute of Arctic Biology, University of Alaska Fairbanks Fairbanks, AK, USA
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