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Xiao C, Gavrilova O, Liu N, Lewicki SA, Reitman ML, Jacobson KA. In vivo phenotypic validation of adenosine receptor-dependent activity of non-adenosine drugs. Purinergic Signal 2023; 19:551-564. [PMID: 36781825 PMCID: PMC10539256 DOI: 10.1007/s11302-023-09924-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Accepted: 01/31/2023] [Indexed: 02/15/2023] Open
Abstract
Some non-adenosinergic drugs are reported to also act through adenosine receptors (ARs). We used mouse hypothermia, which can be induced by agonism at any of the four ARs, as an in vivo screen for adenosinergic effects. An AR contribution was identified when a drug caused hypothermia in wild type mice that was diminished in mice lacking all four ARs (quadruple knockout, QKO). Alternatively, an adenosinergic effect was identified if a drug potentiated adenosine-induced hypothermia. Four drugs (dipyridamole, nimodipine, cilostazol, cyclosporin A) increased the hypothermia caused by adenosine. Dipyridamole and nimodipine probably achieved this by inhibition of adenosine clearance via ENT1. Two drugs (cannabidiol, canrenoate) did not cause hypothermia in wild type mice. Four other drugs (nifedipine, ranolazine, ketamine, ethanol) caused hypothermia, but the hypothermia was unchanged in QKO mice indicating non-adenosinergic mechanisms. Zinc chloride caused hypothermia and hypoactivity; the hypoactivity was blunted in the QKO mice. Interestingly, the antidepressant amitriptyline caused hypothermia in wild type mice that was amplified in the QKO mice. Thus, we have identified adenosine-related effects for some drugs, while other candidates do not affect adenosine signaling by this in vivo assay. The adenosine-modulating drugs could be considered for repurposing based on predicted effects on AR activation.
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Affiliation(s)
- Cuiying Xiao
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Disease, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD, 20892-0810, USA
| | - Oksana Gavrilova
- Mouse Metabolism Core, National Institute of Diabetes and Digestive and Kidney Disease, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD, 20892-0810, USA
| | - Naili Liu
- Mouse Metabolism Core, National Institute of Diabetes and Digestive and Kidney Disease, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD, 20892-0810, USA
| | - Sarah A Lewicki
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Disease, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD, 20892-0810, USA
| | - Marc L Reitman
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Disease, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD, 20892-0810, USA
| | - Kenneth A Jacobson
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Disease, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD, 20892-0810, USA.
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2
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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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3
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Ambler M, Hitrec T, Pickering A. Turn it off and on again: characteristics and control of torpor. Wellcome Open Res 2022; 6:313. [PMID: 35087956 PMCID: PMC8764563 DOI: 10.12688/wellcomeopenres.17379.2] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/14/2022] [Indexed: 11/20/2022] Open
Abstract
Torpor is a hypothermic, hypoactive, hypometabolic state entered into by a wide range of animals in response to environmental challenge. This review summarises the current understanding of torpor. We start by describing the characteristics of the wide-ranging physiological adaptations associated with torpor. Next follows a discussion of thermoregulation, control of food intake and energy expenditure, and the interactions of sleep and thermoregulation, with particular emphasis on how those processes pertain to torpor. We move on to review the evidence for the systems that control torpor entry, including both the efferent circulating factors that signal the need for torpor, and the central processes that orchestrate it. Finally, we consider how the putative circuits responsible for torpor induction integrate with the established understanding of thermoregulation under non-torpid conditions and highlight important areas of uncertainty for future studies.
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Affiliation(s)
- Michael Ambler
- School of Physiology, Pharmacology, & Neuroscience, University of Bristol, Bristol, Bristol, BS8 1TD, UK
| | - Timna Hitrec
- School of Physiology, Pharmacology, & Neuroscience, University of Bristol, Bristol, Bristol, BS8 1TD, UK
| | - Anthony Pickering
- School of Physiology, Pharmacology, & Neuroscience, University of Bristol, Bristol, Bristol, BS8 1TD, UK
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4
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Ambler M, Hitrec T, Pickering A. Turn it off and on again: characteristics and control of torpor. Wellcome Open Res 2021; 6:313. [DOI: 10.12688/wellcomeopenres.17379.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/12/2021] [Indexed: 11/20/2022] Open
Abstract
Torpor is a hypothermic, hypoactive, hypometabolic state entered into by a wide range of animals in response to environmental challenge. This review summarises the current understanding of torpor. We start by describing the characteristics of the wide-ranging physiological adaptations associated with torpor. Next follows a discussion of thermoregulation, control of food intake and energy expenditure, and the interactions of sleep and thermoregulation, with particular emphasis on how those processes pertain to torpor. We move on to take a critical view of the evidence for the systems that control torpor entry, including both the efferent circulating factors that signal the need for torpor, and the central processes that orchestrate it. Finally, we consider how the putative circuits responsible for torpor induction integrate with the established understanding of thermoregulation under non-torpid conditions and highlight important areas of uncertainty for future studies.
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5
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Province HS, Xiao C, Mogul AS, Sahoo A, Jacobson KA, Piñol RA, Gavrilova O, Reitman ML. Activation of neuronal adenosine A1 receptors causes hypothermia through central and peripheral mechanisms. PLoS One 2020; 15:e0243986. [PMID: 33326493 PMCID: PMC7743955 DOI: 10.1371/journal.pone.0243986] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Accepted: 12/01/2020] [Indexed: 12/12/2022] Open
Abstract
Extracellular adenosine, a danger signal, can cause hypothermia. We generated mice lacking neuronal adenosine A1 receptors (A1AR, encoded by the Adora1 gene) to examine the contribution of these receptors to hypothermia. Intracerebroventricular injection of the selective A1AR agonist (Cl-ENBA, 5'-chloro-5'-deoxy-N6-endo-norbornyladenosine) produced hypothermia, which was reduced in mice with deletion of A1AR in neurons. A non-brain penetrant A1AR agonist [SPA, N6-(p-sulfophenyl) adenosine] also caused hypothermia, in wild type but not mice lacking neuronal A1AR, suggesting that peripheral neuronal A1AR can also cause hypothermia. Mice expressing Cre recombinase from the Adora1 locus were generated to investigate the role of specific cell populations in body temperature regulation. Chemogenetic activation of Adora1-Cre-expressing cells in the preoptic area did not change body temperature. In contrast, activation of Adora1-Cre-expressing dorsomedial hypothalamus cells increased core body temperature, concordant with agonism at the endogenous inhibitory A1AR causing hypothermia. These results suggest that A1AR agonism causes hypothermia via two distinct mechanisms: brain neuronal A1AR and A1AR on neurons outside the blood-brain barrier. The variety of mechanisms that adenosine can use to induce hypothermia underscores the importance of hypothermia in the mouse response to major metabolic stress or injury.
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Affiliation(s)
- Haley S. Province
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, Maryland, United States of America
| | - Cuiying Xiao
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, Maryland, United States of America
| | - Allison S. Mogul
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, Maryland, United States of America
| | - Ankita Sahoo
- Mouse Metabolism Core, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, Maryland, United States of America
| | - Kenneth A. Jacobson
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, Maryland, United States of America
| | - Ramón A. Piñol
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, Maryland, United States of America
| | - Oksana Gavrilova
- Mouse Metabolism Core, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, Maryland, United States of America
| | - Marc L. Reitman
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, Maryland, United States of America
- * E-mail:
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6
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Xie AX, Madayag A, Minton SK, McCarthy KD, Malykhina AP. Sensory satellite glial Gq-GPCR activation alleviates inflammatory pain via peripheral adenosine 1 receptor activation. Sci Rep 2020; 10:14181. [PMID: 32843670 PMCID: PMC7447794 DOI: 10.1038/s41598-020-71073-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 08/10/2020] [Indexed: 02/07/2023] Open
Abstract
Glial fibrillary acidic protein expressing (GFAP+) glia modulate nociceptive neuronal activity in both the peripheral nervous system (PNS) and the central nervous system (CNS). Resident GFAP+ glia in dorsal root ganglia (DRG) known as satellite glial cells (SGCs) potentiate neuronal activity by releasing pro-inflammatory cytokines and neuroactive compounds. In this study, we tested the hypothesis that SGC Gq-coupled receptor (Gq-GPCR) signaling modulates pain sensitivity in vivo using Gfap-hM3Dq mice. Complete Freund's adjuvant (CFA) was used to induce inflammatory pain, and mechanical sensitivity and thermal sensitivity were used to assess the neuromodulatory effect of glial Gq-GPCR activation in awake mice. Pharmacogenetic activation of Gq-GPCR signaling in sensory SGCs decreased heat-induced nociceptive responses and reversed inflammation-induced mechanical allodynia via peripheral adenosine A1 receptor activation. These data reveal a previously unexplored role of sensory SGCs in decreasing afferent excitability. The identified molecular mechanism underlying the analgesic role of SGCs offers new approaches for reversing peripheral nociceptive sensitization.
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MESH Headings
- Animals
- Benzilates/pharmacology
- Clozapine/analogs & derivatives
- Clozapine/pharmacology
- Freund's Adjuvant/toxicity
- GTP-Binding Protein alpha Subunits, Gq-G11/physiology
- Genes, Synthetic
- Hot Temperature
- Hyperalgesia/physiopathology
- Hyperalgesia/prevention & control
- Inflammation/chemically induced
- Inflammation/physiopathology
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Transgenic
- Muscarinic Agonists/pharmacology
- Neuroglia/enzymology
- Neuroglia/physiology
- Nociception/physiology
- Nortropanes/pharmacology
- Promoter Regions, Genetic
- Purinergic P1 Receptor Agonists/pharmacology
- Purinergic P1 Receptor Antagonists/pharmacology
- Receptor, Adenosine A1/drug effects
- Receptor, Adenosine A1/physiology
- Receptor, Muscarinic M3/drug effects
- Receptor, Muscarinic M3/genetics
- Receptor, Muscarinic M3/physiology
- Receptors, G-Protein-Coupled
- Recombinant Fusion Proteins/drug effects
- Recombinant Fusion Proteins/metabolism
- Theophylline/analogs & derivatives
- Theophylline/pharmacology
- Touch
- Xanthines/pharmacology
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Affiliation(s)
- Alison Xiaoqiao Xie
- Department of Pharmacology, School of Medicine, University of North Carolina at Chapel Hill (UNC-CH), Chapel Hill, USA.
- Division of Urology, Department of Surgery, University of Colorado Denver (UCD), Anschutz Medical Campus (AMC), 12700E 19th Ave., Room 6440D, Mail stop C317, Aurora, CO, 80045, USA.
- Department of Surgery, UCD-AMC, Aurora, CO, USA.
| | - Aric Madayag
- Department of Pharmacology, School of Medicine, University of North Carolina at Chapel Hill (UNC-CH), Chapel Hill, USA
- NeuroCycle Therapeutics, Inc., 3829 N Cramer St., Shorewood, WI, 53211, USA
| | - Suzanne K Minton
- Department of Pharmacology, School of Medicine, University of North Carolina at Chapel Hill (UNC-CH), Chapel Hill, USA
- Certara, 5511 Capital Center Drive, Ste. 204, Raleigh, NC, 27606, USA
| | - Ken D McCarthy
- Professor Emeritus in the Department of Pharmacology, School of Medicine, University of North Carolina at Chapel Hill, 120 Mason Farm Road, 4010 Genetic Medicine Bldg, Campus Box 7365, Chapel Hill, NC, 27599-7365, USA
| | - Anna P Malykhina
- Division of Urology, Department of Surgery, University of Colorado Denver (UCD), Anschutz Medical Campus (AMC), 12700E 19th Ave., Room 6440D, Mail stop C317, Aurora, CO, 80045, USA
- Department of Physiology and Biophysics, University of Colorado School of Medicine, 12700 East 19th Ave., Rm 6001, Mail Stop C317, Aurora, CO, 80045, USA
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7
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Xiao C, Liu N, Jacobson KA, Gavrilova O, Reitman ML. Physiology and effects of nucleosides in mice lacking all four adenosine receptors. PLoS Biol 2019; 17:e3000161. [PMID: 30822301 PMCID: PMC6415873 DOI: 10.1371/journal.pbio.3000161] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 03/13/2019] [Accepted: 02/07/2019] [Indexed: 11/29/2022] Open
Abstract
Adenosine is a constituent of many molecules of life; increased free extracellular adenosine indicates cell damage or metabolic stress. The importance of adenosine signaling in basal physiology, as opposed to adaptive responses to danger/damage situations, is unclear. We generated mice lacking all four adenosine receptors (ARs), Adora1−/−;Adora2a−/−;Adora2b−/−;Adora3−/− (quad knockout [QKO]), to enable investigation of the AR dependence of physiologic processes, focusing on body temperature. The QKO mice demonstrate that ARs are not required for growth, metabolism, breeding, and body temperature regulation (diurnal variation, response to stress, and torpor). However, the mice showed decreased survival starting at about 15 weeks of age. While adenosine agonists cause profound hypothermia via each AR, adenosine did not cause hypothermia (or bradycardia or hypotension) in QKO mice, indicating that AR-independent signals do not contribute to adenosine-induced hypothermia. The hypothermia elicited by adenosine kinase inhibition (with A134974), inosine, or uridine also required ARs, as each was abolished in the QKO mice. The proposed mechanism for uridine-induced hypothermia is inhibition of adenosine transport by uridine, increasing local extracellular adenosine levels. In contrast, adenosine 5′-monophosphate (AMP)–induced hypothermia was attenuated in QKO mice, demonstrating roles for both AR-dependent and AR-independent mechanisms in this process. The physiology of the QKO mice appears to be the sum of the individual knockout mice, without clear evidence for synergy, indicating that the actions of the four ARs are generally complementary. The phenotype of the QKO mice suggests that, while extracellular adenosine is a signal of stress, damage, and/or danger, it is less important for baseline regulation of body temperature. A study of mice lacking all four adenosine receptors shows that while they mediate effects of uridine, inosine and adenosine, these receptors are dispensable for growth, metabolism, breeding, and body temperature regulation. This suggests that extracellular adenosine is a damage or danger signal, rather than a major regulator of baseline physiology. Elevated extracellular adenosine generally indicates metabolic stress or cell damage and regulates many aspects of physiology. We studied “QKO” mice lacking all four adenosine receptors. Young QKO mice do not appear obviously ill, but do show decreased survival later in life. QKO mice demonstrate that adenosine receptors are not required for growth, metabolism, breeding, and body temperature regulation. QKO mice are missing the pharmacologic effects of adenosine on body temperature, heart rate, and blood pressure. Therefore, all of these effects are mediated by the four adenosine receptors. We also determined that the hypothermic effects of a pharmacologic adenosine kinase inhibitor (A134974), uridine, or inosine each requires adenosine receptors. The uridine-induced hypothermia is likely due to its inhibition of adenosine uptake into cells. QKO mouse physiology appears to be the sum of the individual knockout mice, without evidence for synergy, indicating that the actions of the four adenosine receptors are generally complementary.
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Affiliation(s)
- Cuiying Xiao
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, Maryland, United States of America
| | - Naili Liu
- Mouse Metabolism Core, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, Maryland, United States of America
| | - Kenneth A. Jacobson
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, Maryland, United States of America
| | - Oksana Gavrilova
- Mouse Metabolism Core, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, Maryland, United States of America
| | - Marc L. Reitman
- Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, Maryland, United States of America
- * E-mail:
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8
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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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9
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Carlin JL, Jain S, Duroux R, Suresh RR, Xiao C, Auchampach JA, Jacobson KA, Gavrilova O, Reitman ML. Activation of adenosine A 2A or A 2B receptors causes hypothermia in mice. Neuropharmacology 2018; 139:268-278. [PMID: 29548686 PMCID: PMC6067974 DOI: 10.1016/j.neuropharm.2018.02.035] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Revised: 01/26/2018] [Accepted: 02/28/2018] [Indexed: 12/25/2022]
Abstract
Extracellular adenosine is a danger/injury signal that initiates protective physiology, such as hypothermia. Adenosine has been shown to trigger hypothermia via agonism at A1 and A3 adenosine receptors (A1AR, A3AR). Here, we find that adenosine continues to elicit hypothermia in mice null for A1AR and A3AR and investigated the effect of agonism at A2AAR or A2BAR. The poorly brain penetrant A2AAR agonists CGS-21680 and PSB-0777 caused hypothermia, which was not seen in mice lacking A2AAR. MRS7352, a likely non-brain penetrant A2AAR antagonist, inhibited PSB-0777 hypothermia. While vasodilation is probably a contributory mechanism, A2AAR agonism also caused hypometabolism, indicating that vasodilation is not the sole mechanism. The A2BAR agonist BAY60-6583 elicited hypothermia, which was lost in mice null for A2BAR. Low intracerebroventricular doses of BAY60-6583 also caused hypothermia, indicating a brain site of action, with neuronal activation in the preoptic area and paraventricular nucleus of the hypothalamus. Thus, agonism at any one of the canonical adenosine receptors, A1AR, A2AAR, A2BAR, or A3AR, can cause hypothermia. This four-fold redundancy in adenosine-mediated initiation of hypothermia may reflect the centrality of hypothermia as a protective response.
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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
| | - Romain Duroux
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD 20892, USA
| | - R Rama Suresh
- 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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10
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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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11
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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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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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13
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Eisner C, Kim S, Grill A, Qin Y, Hoerl M, Briggs J, Castrop H, Thiel M, Schnermann J. Profound hypothermia after adenosine kinase inhibition in A1AR-deficient mice suggests a receptor-independent effect of intracellular adenosine. Pflugers Arch 2016; 469:339-347. [PMID: 27975140 DOI: 10.1007/s00424-016-1925-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Revised: 11/28/2016] [Accepted: 11/30/2016] [Indexed: 10/20/2022]
Abstract
Administration of the nucleoside adenosine has been shown to induce hypothermia in a number of species, an effect mediated predominantly by the adenosine 1 receptor (A1AR) subtype. The present experiments were performed to explore the possibility that the rise of intracellular adenosine levels expected to accompany adenosine administration may contribute to the hypothermic effect of adenosine independent of A1AR activation. Since phosphorylation of adenosine by adenosine kinase (ADK) is causal in the maintenance of low intracellular adenosine, we have examined the effect of ADK inhibition on core body temperature (CBT). Our data show that inhibition of ADK by A-134974 causes a long-lasting deep hypothermia in wild-type mice. Since there was an about 4-fold increase of adenosine plasma levels, experiments were repeated in A1AR-/- mice. ADK inhibition caused deep hypothermia despite the absence of A1AR, although the effect was significantly reduced compared to WT. Furthermore, the dose-dependent hypothermia caused by adenosine administration in WT mice was found to be reduced, but not abolished in A1AR-/- mice. To assess the possible role of A2AR and A3AR activation in our experimental setting, we compared the effects of the agonists CPA (A1AR), CGS21680 (A2AR), and IB-MECA (A3AR) on CBT. Hypothermia induced by CPA was much greater than that caused by CGS21680 or IB-MECA indicating that A1AR activation is the major receptor-dependent pathway for adenosine-induced hypothermia under our experimental conditions. Induction of deep hypothermia by inhibition of ADK, maintenance of this effect in A1AR-/- mice, and maintenance of adenosine-induced hypothermia in A1AR-deficient mice suggest that a receptor-independent action of adenosine requiring intact function of adenosine kinase contributes importantly to the hypothermia induced by adenosine.
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Affiliation(s)
- Christoph Eisner
- National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, USA. .,Department of Anesthesiology, Heidelberg University Hospital, Heidelberg, Germany.
| | - SooMi Kim
- National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, USA
| | - Alexandra Grill
- Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Yan Qin
- National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, USA
| | - Marion Hoerl
- Department of Anesthesiology, LMU, Munich, Germany
| | - Josephine Briggs
- National Center of Complementary and Integrative Health, Bethesda, MD, USA
| | - Hayo Castrop
- Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Manfred Thiel
- Department of Anesthesiology and Critical Care, University Medicine Mannheim, Mannheim, Germany
| | - Jurgen Schnermann
- National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, USA
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14
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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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15
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Zheng X, Hasegawa H. Administration of caffeine inhibited adenosine receptor agonist-induced decreases in motor performance, thermoregulation, and brain neurotransmitter release in exercising rats. Pharmacol Biochem Behav 2015; 140:82-9. [PMID: 26604076 DOI: 10.1016/j.pbb.2015.10.019] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Revised: 10/26/2015] [Accepted: 10/27/2015] [Indexed: 11/15/2022]
Abstract
We examined the effects of an adenosine receptor agonist on caffeine-induced changes in thermoregulation, neurotransmitter release in the preoptic area and anterior hypothalamus, and endurance exercise performance in rats. One hour before the start of exercise, rats were intraperitoneally injected with either saline alone (SAL), 10 mg kg(-1) caffeine and saline (CAF), a non-selective adenosine receptor agonist (5'-N-ethylcarboxamidoadenosine [NECA]: 0.5 mg kg(-1)) and saline (NECA), or the combination of caffeine and NECA (CAF+NECA). Rats ran until fatigue on the treadmill with a 5% grade at a speed of 18 m min(-1) at 23 °C. Compared to the SAL group, the run time to fatigue (RTTF) was significantly increased by 52% following caffeine administration and significantly decreased by 65% following NECA injection (SAL: 91 ± 14.1 min; CAF: 137 ± 25.8 min; NECA: 31 ± 13.7 min; CAF+NECA: 85 ± 11.8 min; p<0.05). NECA decreased the core body temperature (Tcore), oxygen consumption, which is an index of heat production, tail skin temperature, which is an index of heat loss, and extracellular dopamine (DA) release at rest and during exercise. Furthermore, caffeine injection inhibited the NECA-induced decreases in the RTTF, Tcore, heat production, heat loss, and extracellular DA release. Neither caffeine nor NECA affected extracellular noradrenaline or serotonin release. These results support the findings of previous studies showing improved endurance performance and overrides in body limitations after caffeine administration, and imply that the ergogenic effects of caffeine may be associated with the adenosine receptor blockade-induced increases in brain DA release.
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Affiliation(s)
- Xinyan Zheng
- Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashihiroshima, Japan
| | - Hiroshi Hasegawa
- Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashihiroshima, Japan.
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16
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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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17
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Ciruela F, Fernández-Dueñas V, Jacobson KA. Lighting up G protein-coupled purinergic receptors with engineered fluorescent ligands. Neuropharmacology 2015; 98:58-67. [PMID: 25890205 DOI: 10.1016/j.neuropharm.2015.04.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2015] [Revised: 03/23/2015] [Accepted: 04/01/2015] [Indexed: 12/31/2022]
Abstract
The use of G protein-coupled receptors fluorescent ligands is undergoing continuous expansion. In line with this, fluorescent agonists and antagonists of high affinity for G protein-coupled adenosine and P2Y receptors have been shown to be useful pharmacological probe compounds. Fluorescent ligands for A1R, A2AR, and A3R (adenosine receptors) and P2Y2R, P2Y4R, P2Y6R, and P2Y14R (nucleotide receptors) have been reported. Such ligands have been successfully applied to drug discovery and to GPCR characterization by flow cytometry, fluorescence correlation spectroscopy, fluorescence microscopy, fluorescence polarization, fluorescence resonance energy transfer and scanning confocal microscopy. Here we summarize recently reported and readily available representative fluorescent ligands of purinergic receptors. In addition, we pay special attention on the use of this family of fluorescent ligands revealing two main aspects of purinergic receptor biology, namely ligand binding and receptor oligomerization. This article is part of the Special Issue entitled 'Fluorescent Tools in Neuropharmacology'.
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Affiliation(s)
- Francisco Ciruela
- Unitat de Farmacologia, Departament Patologia i Terapèutica Experimental, Facultat de Medicina, IDIBELL, Universitat de Barcelona, 08907 L'Hospitalet de Llobregat, Spain; Department of Physiology, Faculty of Sciences, University of Ghent, 9000 Gent, Belgium.
| | - Víctor Fernández-Dueñas
- Unitat de Farmacologia, Departament Patologia i Terapèutica Experimental, Facultat de Medicina, IDIBELL, Universitat de Barcelona, 08907 L'Hospitalet de Llobregat, Spain
| | - Kenneth A Jacobson
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, 20892 Bethesda, USA.
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18
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Zhang M, Wang H, Zhao J, Chen C, Leak RK, Xu Y, Vosler P, Chen J, Gao Y, Zhang F. Drug-induced hypothermia in stroke models: does it always protect? CNS & NEUROLOGICAL DISORDERS-DRUG TARGETS 2014; 12:371-80. [PMID: 23469851 DOI: 10.2174/1871527311312030010] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2012] [Revised: 11/06/2012] [Accepted: 11/11/2012] [Indexed: 12/19/2022]
Abstract
Ischemic stroke is a common neurological disorder lacking a cure. Recent studies show that therapeutic hypothermia is a promising neuroprotective strategy against ischemic brain injury. Several methods to induce therapeutic hypothermia have been established; however, most of them are not clinically feasible for stroke patients. Therefore, pharmacological cooling is drawing increasing attention as a neuroprotective alternative worthy of further clinical development. We begin this review with a brief introduction to the commonly used methods for inducing hypothermia; we then focus on the hypothermic effects of eight classes of hypothermia-inducing drugs: the cannabinoids, opioid receptor activators, transient receptor potential vanilloid, neurotensins, thyroxine derivatives, dopamine receptor activators, hypothermia-inducing gases, adenosine, and adenine nucleotides. Their neuroprotective effects as well as the complications associated with their use are both considered. This article provides guidance for future clinical trials and animal studies on pharmacological cooling in the setting of acute stroke.
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Affiliation(s)
- Meijuan Zhang
- Department of Neurology, University of Pittsburgh School of Medicine, 3500 Terrace Street, Pittsburgh, PA 15213, USA
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19
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Thomas TP, Shih TM. Stimulation of central A1 adenosine receptors suppresses seizure and neuropathology in a soman nerve agent seizure rat model. Toxicol Mech Methods 2014; 24:385-95. [DOI: 10.3109/15376516.2014.920450] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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20
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Olson JM, Jinka TR, Larson LK, Danielson JJ, Moore JT, Carpluck J, Drew KL. Circannual rhythm in body temperature, torpor, and sensitivity to A₁ adenosine receptor agonist in arctic ground squirrels. J Biol Rhythms 2013; 28:201-7. [PMID: 23735499 DOI: 10.1177/0748730413490667] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
A₁ adenosine receptor (A₁AR) activation within the central nervous system induces torpor, but in obligate hibernators such as the arctic ground squirrel (AGS; Urocitellus parryii), A₁AR stimulation induces torpor only during the hibernation season, suggesting a seasonal increase in sensitivity to A₁AR signaling. The purpose of this research was to investigate the relationship between body temperature (Tb) and sensitivity to an adenosine A1 receptor agonist in AGS. We tested the hypothesis that increased sensitivity in A₁AR signaling would lead to lower Tb in euthermic animals during the hibernation season when compared with the summer season. We further predicted that if a decrease in euthermic Tb reflects increased sensitivity to A₁AR activation, then it should likewise predict spontaneous torpor. We used subcutaneous IPTT-300 transponders to monitor Tb in AGS housed under constant ambient conditions (12:12 L:D, 18 °C) for up to 16 months. These animals displayed an obvious rhythm in euthermic Tb that cycled with a period of approximately 8 months. Synchrony in the Tb rhythm within the group was lost after several months of constant L:D conditions; however, individual rhythms in Tb continued to show clear sine wave-like waxing and waning. AGS displayed spontaneous torpor only during troughs in euthermic Tb. To assess sensitivity to A₁AR activation, AGS were administered the A₁AR agonist N(6)-cyclohexyladenosine (CHA, 0.1 mg/kg, ip), and subcutaneous Tb was monitored. AGS administered CHA during a seasonal minimum in euthermic Tb showed a greater drug-induced decrease in Tb (1.6 ± 0.3 °C) than did AGS administered CHA during a peak in euthermic Tb (0.4 ± 0.3 °C). These results provide evidence for a circannual rhythm in Tb that is associated with increased sensitivity to A₁AR signaling and correlates with the onset of torpor.
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Affiliation(s)
- Jasmine M Olson
- Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK 99775-7000, USA
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21
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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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22
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Rawls SM, Benamar K. Effects of opioids, cannabinoids, and vanilloids on body temperature. Front Biosci (Schol Ed) 2011; 3:822-45. [PMID: 21622235 DOI: 10.2741/190] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Cannabinoid and opioid drugs produce marked changes in body temperature. Recent findings have extended our knowledge about the thermoregulatory effects of cannabinoids and opioids, particularly as related to delta opioid receptors, endogenous systems, and transient receptor potential (TRP) channels. Although delta opioid receptors were originally thought to play only a minor role in thermoregulation compared to mu and kappa opioid receptors, their activation has been shown to produce hypothermia in multiple species. Endogenous opioids and cannabinoids also regulate body temperature. Mu and kappa opioid receptors are thought to be in tonic balance, with mu and kappa receptor activation producing hyperthermia and hypothermia, respectively. A particularly intense research focus is TRP channels, where TRPV1 channel activation produces hypothermia whereas TRPA1 and TRPM8 channel activation causes hyperthermia. The marked hyperthermia produced by TRPV1 channel antagonists suggests these warm channels tonically control body temperature. A better understanding of the roles of cannabinoid, opioid, and TRP systems in thermoregulation may have broad clinical implications and provide insights into interactions among neurotransmitter systems involved in thermoregulation.
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Affiliation(s)
- Scott M Rawls
- Department of Pharmaceutical Sciences, Temple University Health Sciences Center, Temple University, Philadelphia, PA 19140, USA.
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23
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Rawls SM, Benamar K. Effects of opioids, cannabinoids, and vanilloids on body temperature. Front Biosci (Schol Ed) 2011. [PMID: 21622235 DOI: 10.2741/s190] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cannabinoid and opioid drugs produce marked changes in body temperature. Recent findings have extended our knowledge about the thermoregulatory effects of cannabinoids and opioids, particularly as related to delta opioid receptors, endogenous systems, and transient receptor potential (TRP) channels. Although delta opioid receptors were originally thought to play only a minor role in thermoregulation compared to mu and kappa opioid receptors, their activation has been shown to produce hypothermia in multiple species. Endogenous opioids and cannabinoids also regulate body temperature. Mu and kappa opioid receptors are thought to be in tonic balance, with mu and kappa receptor activation producing hyperthermia and hypothermia, respectively. A particularly intense research focus is TRP channels, where TRPV1 channel activation produces hypothermia whereas TRPA1 and TRPM8 channel activation causes hyperthermia. The marked hyperthermia produced by TRPV1 channel antagonists suggests these warm channels tonically control body temperature. A better understanding of the roles of cannabinoid, opioid, and TRP systems in thermoregulation may have broad clinical implications and provide insights into interactions among neurotransmitter systems involved in thermoregulation.
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Affiliation(s)
- Scott M Rawls
- Department of Pharmaceutical Sciences, Temple University Health Sciences Center, Temple University, Philadelphia, PA 19140, USA.
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Repetitive stimulation of adenosine A1 receptors in vivo: Changes in receptor numbers, G-proteins and A1 receptor agonist-induced hypothermia. Brain Res 2008; 1191:69-74. [DOI: 10.1016/j.brainres.2007.11.044] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2007] [Revised: 11/26/2007] [Accepted: 11/27/2007] [Indexed: 11/23/2022]
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Abstract
The introduction of therapeutic mild hypothermia after cardiac arrest allows the neuronal damage caused by global cerebral ischemia to be advantageously influenced for the first time. Currently, hypothermia is induced by external or internal cooling of the patient (forced hypothermia). However, this results in activation of counter-regulation mechanisms which could be possible risk factors for the patient. The aim of this article is to give a review of possible, but at present only experimental, methods which could allow the body temperature set point to be decreased pharmacologically (regulated hypothermia). Various classes of substances will be discussed based on their effect on thermoregulation and their performance in animal experiments on cerebral ischemia.
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Affiliation(s)
- A Schneider
- Klinik für Anaesthesiologie, Universitätsklinikum, Im Neuenheimer Feld 110, 69120 Heidelberg
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26
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Costa ACS, Stasko MR, Stoffel M, Scott-McKean JJ. G-protein-gated potassium (GIRK) channels containing the GIRK2 subunit are control hubs for pharmacologically induced hypothermic responses. J Neurosci 2006; 25:7801-4. [PMID: 16120781 PMCID: PMC6725253 DOI: 10.1523/jneurosci.1699-05.2005] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Hypothermic responses of rodents to the peripheral or intraventricular injection of many individual neurotransmitter receptor agonists have been well documented. Because many hypothermia-inducing agonists are also known to activate G-protein-gated potassium (GIRK) channels, we investigated the hypothermic response to several of these agents on Girk2 null mutant mice. Core body temperatures were measured through radiotelemetry, and animals were maintained in special temperature-regulated chambers to ensure the accuracy of the measurements. The resulting data indicate that the activation of GIRK2-containing potassium channels plays a significant role in hypothermia induced by the activation of serotonergic (5-HT(1A)), GABAergic (GABA(B)), muscarinic (m2), adenosine (A1), and mu, delta, and kappa opioid receptors. These channels also are involved in the alcohol-induced hypothermic response. These results have implications for the understanding of pharmacologically induced hypothermia and thermoregulatory mechanisms.
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Affiliation(s)
- Alberto C S Costa
- Eleanor Roosevelt Institute, University of Denver, Denver, Colorado 80206, USA.
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Olsson T, Cronberg T, Rytter A, Asztély F, Fredholm BB, Smith ML, Wieloch T. Deletion of the adenosine A1 receptor gene does not alter neuronal damage following ischaemia in vivo or in vitro. Eur J Neurosci 2004; 20:1197-204. [PMID: 15341591 DOI: 10.1111/j.1460-9568.2004.03564.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Extracellular adenosine is dramatically increased during cerebral ischaemia and is considered to be neuroprotective due to its inhibitory effect on synaptic transmission mediated by the adenosine A1 receptor (A1R). We investigated the importance of the A1R in a mouse model of global ischaemia and in a murine hippocampal slice culture model of in vitro ischaemia, using mice with the A1R gene deleted. In brains from mice lacking the A1R, damage induced by global ischaemia was similar to that in wild-type animals. In contrast, treatment with a selective A1R antagonist [8-cyclo-pentyl theophylline (8-CPT)], administered before the ischaemic insult in naive wild-type mice, exacerbated the neuronal damage following global ischaemia. Although the inhibitory action of adenosine on excitatory neurotransmission in hippocampal slices was lost in A1R knockout mice, there was no difference in damage between slices from wild-type and knockout mice after in vitro ischaemia. The results suggest that some effects of the A1R are compensated for in knockout animals.
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Affiliation(s)
- Tomas Olsson
- Laboratory for Experimental Brain Research, Wallenberg Neuroscience Center, Lund University, BMC A13, SE-221 84, Sweden.
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28
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Blum D, Hourez R, Galas MC, Popoli P, Schiffmann SN. Adenosine receptors and Huntington's disease: implications for pathogenesis and therapeutics. Lancet Neurol 2003; 2:366-74. [PMID: 12849153 DOI: 10.1016/s1474-4422(03)00411-3] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Huntington's disease (HD) is a devastating hereditary neurodegenerative disorder, the progression of which cannot be prevented by any neuroprotective approach, despite major advances in the understanding of its pathogenesis. The study of several animal models of the disease has led to the discovery of both loss-of-normal and gain-of-toxic functions of the mutated huntingtin protein and the elucidation of the mechanisms that underlie the formation of huntingtin aggregates and nuclear inclusions. Moreover, these models also provide good evidence of a role for excitotoxicity and mitochondrial metabolic impairments in striatal neuronal death. Adenosine has neuroprotective potential in both acute and chronic neurological disorders such as stroke or Parkinson's disease. Here we review experimental data on the role of A1 and A2A adenosine receptors in HD that warrant further investigation of the beneficial effects of A1 agonists and A2A antagonists in animal models of HD. Future pharmacological analysis of adenosine receptors could justify the use of A1 agonists and A2A antagonists for the treatment of HDin clinical trials.
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Affiliation(s)
- David Blum
- Laboratory of Neurophysiology, Université Libre de Bruxelles, Belgium.
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Petersen AM, Gleeson TT, Scholnick DA. The effect of oxygen and adenosine on lizard thermoregulation. Physiol Biochem Zool 2003; 76:339-47. [PMID: 12905120 DOI: 10.1086/375429] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/18/2003] [Indexed: 11/04/2022]
Abstract
A regulated decrease in internal body temperature (Tb) appears to play a protective role against metabolic disruptions such as exposure to ambient hypoxia. This study examined the possibility that Tb depression is initiated when low internal oxygen levels trigger the release of adenosine, a neural modulator known to influence thermoregulation. We measured selected Tb of Anolis sagrei in a thermal gradient under varied ambient oxygen conditions and following the administration of the adenosine receptor antagonist 8-cyclopentyltheophylline (CPT). The average decrease in Tb observed following exposure to hypoxia (<10% O2) and following exhaustive exercise were 5 degrees and 3 degrees C, respectively, suggesting a role of oxygen availability on initiation of regulated hypothermia. When A. sagrei were run to exhaustion and recovered in hyperoxic (>95% O2) conditions, exercise-induced Tb depression was abolished. Administration of CPT similarly abolished decreased Tb due to both exercise and hypoxia. Trials using Dipsosaurus dorsalis indicate that elevated ambient oxygen during exercise does not influence blood pH or lactate accumulation, suggesting that these factors do not initiate changes in thermoregulatory setpoint following exhaustive exercise. We suggest that when oxygen is limiting, a decrease in arterial oxygen may trigger the release of adenosine, thereby altering the thermoregulatory setpoint.
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Affiliation(s)
- Ann M Petersen
- Department of Biology, Eckerd College, St. Petersburg, Florida 33711, USA
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30
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Abstract
Agonist stimulation of adenosine A(1) receptors has been consistently shown to result in reduction of brain damage following experimentally induced global and focal brain ischaemia in animals. Unsurprisingly, the use of adenosine A(1) receptors as targets for the development of clinical therapeutics suitable for treatment of ischaemic brain disorders has been suggested by many authors. The latest studies of adenosine and its receptors indicate that adenosine-mediated actions might be far more complex than originally anticipated, casting some doubt about the rapid development of stroke treatment based on adenosine. This review discusses the possible role of adenosine receptor subtypes (A(1), A(2) and A(3)) in the context of their potential as therapeutics in stroke.
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Affiliation(s)
- D K von Lubitz
- Emergency Medicine Research Laboratories, Department of Emergency Medicine, University of Michigan Medical Center, TC/B1354/0303, 1500 E. Medical Center Drive, Ann Arbor, MI 48109-0303, USA.
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31
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de Mendonça A, Sebastião AM, Ribeiro JA. Adenosine: does it have a neuroprotective role after all? BRAIN RESEARCH. BRAIN RESEARCH REVIEWS 2000; 33:258-74. [PMID: 11011069 DOI: 10.1016/s0165-0173(00)00033-3] [Citation(s) in RCA: 200] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
A neuroprotective role for adenosine is commonly assumed. Recent studies revealed that adenosine may unexpectedly, under certain circumstances, have the opposite effects contributing to neuronal damage and death. The basis for this duality may be the activation of distinct subtypes of adenosine receptors, interactions between these receptors, differential actions on neuronal and glial cells, and various time frames of adenosinergic compounds administration. If these aspects are understood, adenosine should remain an interesting target for therapeutical neuroprotective approaches after all.
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Affiliation(s)
- A de Mendonça
- Laboratory of Neurosciences, Faculty of Medicine of Lisbon, Av. Professor Egas Moniz, 1649-035, Lisbon, Portugal.
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32
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Branco LG, Steiner AA, Tattersall GJ, Wood SC. Role of adenosine in the hypoxia-induced hypothermia of toads. Am J Physiol Regul Integr Comp Physiol 2000; 279:R196-201. [PMID: 10896882 DOI: 10.1152/ajpregu.2000.279.1.r196] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The concept that hypoxia elicits a drop in body temperature (T(b)) in a wide variety of animals is not new, but the mechanisms remain unclear. We tested the hypothesis that adenosine mediates hypoxia-induced hypothermia in toads. Measurements of selected T(b) were performed using a thermal gradient. Animals were injected (into the lymph sac or intracerebroventricularly) with aminophylline (an adenosine receptor antagonist) followed by an 11-h period of hypoxia (7% O(2)) or normoxia exposure. Control animals received saline injections. Hypoxia elicited a drop in T(b) from 24.8 +/- 0.3 to 19. 5 +/- 1.1 degrees C (P < 0.05). Systemically applied aminophylline (25 mg/kg) did not change T(b) during normoxia, indicating that adenosine does not alter normal thermoregulatory function. However, aminophylline (25 mg/kg) significantly blunted hypoxia-induced hypothermia (P < 0.05). To assess the role of central thermoregulatory mechanisms, a smaller dose of aminophylline (0.25 mg/kg), which did not alter hypoxia-induced hypothermia systemically, was injected into the fourth cerebral ventricle. Intracerebroventricular injection of aminophylline (0.25 mg/kg) caused no significant change in T(b) under normoxia, but it abolished hypoxia-induced hypothermia. The present data indicate that adenosine is a central and possibly peripheral mediator of hypoxia-induced hypothermia.
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Affiliation(s)
- L G Branco
- Faculdade de Odontologia de Ribeirão Preto, Universidade de São Paulo, 14040-904, Ribeirão Preto, São Paulo, Brasil
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Bossenmeyer-Pourié C, Koziel V, Daval JL. Effects of hypothermia on hypoxia-induced apoptosis in cultured neurons from developing rat forebrain: comparison with preconditioning. Pediatr Res 2000; 47:385-91. [PMID: 10709740 DOI: 10.1203/00006450-200003000-00017] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
In neuronal cultures from the forebrain of 14-d-old rat embryos, transient hypoxia (95% N2/5% CO2, 37 degrees C) for 6 h has been shown to trigger delayed apoptotic death through sequential changes in protein synthesis, whereas preconditioning by a brief episode of hypoxia can rescue neurons. Because hypothermia has been reported to be neuroprotective, the present study was designed to test the influence of reduced temperature on the consequences of lethal hypoxia in our culture model, and cellular mechanisms involved were compared with those underlying preconditioning effects. After 6 d in vitro, cultures were subjected to hypoxia for 6 h. They were either placed at 32 degrees C concomitantly with hypoxia for 6 h or preconditioned the day before by a 1-h episode of hypoxia. The hypoxic insult decreased cell viability by 38% at 96 h after reoxygenation, and 23% of the neurons showed morphologic features of apoptosis. Both hypothermia and preconditioning prevented neuronal death and reduced apoptosis. Preconditioning led to time-dependent changes in leucine incorporation, with persistent overexpression of the survival proteins Bcl-2 and heat-shock protein 70. It also increased thymidine incorporation, in line with induction of the cofactor for DNA polymerase, proliferating cell nuclear antigen. Hypothermia reduced basal apoptosis and necrosis, but did not affect thymidine incorporation, and abolished hypoxia-associated protein synthesis. Therefore, both treatments were protective against neuronal injury consecutive to hypoxia in developing brain neurons in vitro. Whereas preconditioning activated a program that stimulated the expression of anti-apoptotic gene products and regulatory components of the cell cycle, hypothermia did not trigger active processes, but depressed cell activity, which in turn may impair the apoptotic phenomenon.
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Crisanti KC, Fewell JE. Aminophylline alters the core temperature response to acute hypoxemia in newborn and older guinea pigs. THE AMERICAN JOURNAL OF PHYSIOLOGY 1999; 277:R829-35. [PMID: 10484500 DOI: 10.1152/ajpregu.1999.277.3.r829] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In newborns and adults of a number of species, exposure to acute hypoxemia produces a "regulated" decrease in core temperature, the mechanism of which is unknown. The present experiments were carried out on chronically instrumented newborn (5-10 days of age; n = 27) and older (25-30 days of age; n = 23) guinea pigs to test the hypothesis that adenosine mediates this regulated decrease in core temperature. During an experiment, core temperature was measured by biotelemetry from animals studied in a thermocline during a control period of normoxemia, an experimental period of normoxemia or acute hypoxemia (fraction of inspired oxygen 0.10), and during a recovery period of normoxemia after an intraperitoneal injection of 10 mg/kg aminophylline (i.e., a nonspecific adenosine antagonist) or vehicle. Core temperature decreased significantly during hypoxemia after vehicle in both newborn and older guinea pigs. After aminophylline, however, newborn guinea pigs failed to significantly decrease their core temperature, whereas older guinea pigs exhibited an attenuated yet significant core temperature decrease during hypoxemia. Our data support the hypothesis that adenosine plays an age-dependent role in mediating the regulated decrease in core temperature that occurs in newborn and older guinea pigs during acute hypoxemia.
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Affiliation(s)
- K C Crisanti
- Department of Physiology and Biophysics, The University of Calgary, Health Sciences Centre, Calgary, Alberta, Canada T2N 4N1
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35
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Abstract
Numerous studies have consistently shown that agonist stimulation of adenosine A1 receptors results in a significant reduction of morbidity and mortality associated with global and focal brain ischemia in animals. Based on these observations, several authors have suggested utilization of adenosine A1 receptors as targets for the development of clinically viable drugs against ischemic brain disorders. Recent advent of adenosine A1 receptor agonists characterized by lowered cardiovascular effects added additional strength to this argument. On the other hand, although cardioprotective, adenosine A3 receptor agonists proved severely cerebrodestructive when administered prior to global ischemia in gerbils. Moreover, stimulation of adenosine A3 receptors appears to reduce the efficacy of some of the neuroprotective actions mediated by adenosine A1 receptors. The review discusses the possible role of adenosine receptor subtypes (A1, A2, and A3) in the context of their involvement in the pathology of cerebral ischemia, and analyzes putative strategies for the development of clinically useful strategies based on adenosine and its receptors. It also stresses the need for further experimental studies before definitive conclusions on the usefulness of the adenosine concept in the treatment of brain ischemia can be made.
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Affiliation(s)
- D K von Lubitz
- Department of Emergency Medicine, University of Michigan Medical Center, Ann Arbor 48109-0303, USA.
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36
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Abstract
Numerous studies have consistently shown that agonist stimulation of adenosine A1 receptors results in a significant reduction of morbidity and mortality associated with global and focal brain ischemia in animals. Based on these observations, several authors have suggested utilization of adenosine A1 receptors as targets for the development of clinically viable drugs against ischemic brain disorders. Recent advent of adenosine A1 receptor agonists characterized by lowered cardiovascular effects added additional strength to this argument. On the other hand, although cardioprotective, adenosine A3 receptor agonists proved severely cerebrodestructive when administered prior to global ischemia in gerbils. Moreover, stimulation of adenosine A3 receptors appears to reduce the efficacy of some of the neuroprotective actions mediated by adenosine A receptors. The review discusses the possible role of adenosine receptor subtypes (A1, A2, and A3) in the context of their involvement in the pathology of cerebral ischemia, and analyzes putative strategies for the development of clinically useful strategies based on adenosine and its receptors. It also stresses the need for further experimental studies before definitive conclusions on the usefulness of the adenosine concept in the treatment of brain ischemia can be made.
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Affiliation(s)
- D K Von Lubitz
- Department of Emergency Medicine, University of Michigan Medical Center, Ann Arbor 48109-0303, USA.
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