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Hanna EG, Tait PW. Limitations to Thermoregulation and Acclimatization Challenge Human Adaptation to Global Warming. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2015; 12:8034-74. [PMID: 26184272 PMCID: PMC4515708 DOI: 10.3390/ijerph120708034] [Citation(s) in RCA: 102] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Revised: 06/15/2015] [Accepted: 06/30/2015] [Indexed: 12/16/2022]
Abstract
Human thermoregulation and acclimatization are core components of the human coping mechanism for withstanding variations in environmental heat exposure. Amidst growing recognition that curtailing global warming to less than two degrees is becoming increasing improbable, human survival will require increasing reliance on these mechanisms. The projected several fold increase in extreme heat events suggests we need to recalibrate health protection policies and ratchet up adaptation efforts. Climate researchers, epidemiologists, and policy makers engaged in climate change adaptation and health protection are not commonly drawn from heat physiology backgrounds. Injecting a scholarly consideration of physiological limitations to human heat tolerance into the adaptation and policy literature allows for a broader understanding of heat health risks to support effective human adaptation and adaptation planning. This paper details the physiological and external environmental factors that determine human thermoregulation and acclimatization. We present a model to illustrate the interrelationship between elements that modulate the physiological process of thermoregulation. Limitations inherent in these processes, and the constraints imposed by differing exposure levels, and thermal comfort seeking on achieving acclimatization, are then described. Combined, these limitations will restrict the likely contribution that acclimatization can play in future human adaptation to global warming. We postulate that behavioral and technological adaptations will need to become the dominant means for human individual and societal adaptations as global warming progresses.
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Affiliation(s)
- Elizabeth G Hanna
- National Centre for Epidemiology and Population Health, Research School of Population Health. Australian National University, Mills St. Acton, ACT 0200, Australia.
| | - Peter W Tait
- National Centre for Epidemiology and Population Health, Research School of Population Health. Australian National University, Mills St. Acton, ACT 0200, Australia.
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102
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Pinkney AE, Driscoll CT, Evers DC, Hooper MJ, Horan J, Jones JW, Lazarus RS, Marshall HG, Milliken A, Rattner BA, Schmerfeld J, Sparling DW. Interactive effects of climate change with nutrients, mercury, and freshwater acidification on key taxa in the North Atlantic Landscape Conservation Cooperative region. INTEGRATED ENVIRONMENTAL ASSESSMENT AND MANAGEMENT 2015; 11:355-69. [PMID: 25556986 DOI: 10.1002/ieam.1612] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Revised: 06/10/2014] [Accepted: 12/12/2014] [Indexed: 05/11/2023]
Abstract
The North Atlantic Landscape Conservation Cooperative LCC (NA LCC) is a public-private partnership that provides information to support conservation decisions that may be affected by global climate change (GCC) and other threats. The NA LCC region extends from southeast Virginia to the Canadian Maritime Provinces. Within this region, the US National Climate Assessment documented increases in air temperature, total precipitation, frequency of heavy precipitation events, and rising sea level, and predicted more drastic changes. Here, we synthesize literature on the effects of GCC interacting with selected contaminant, nutrient, and environmental processes to adversely affect natural resources within this region. Using a case study approach, we focused on 3 stressors with sufficient NA LCC region-specific information for an informed discussion. We describe GCC interactions with a contaminant (Hg) and 2 complex environmental phenomena-freshwater acidification and eutrophication. We also prepared taxa case studies on GCC- and GCC-contaminant/nutrient/process effects on amphibians and freshwater mussels. Several avian species of high conservation concern have blood Hg concentrations that have been associated with reduced nesting success. Freshwater acidification has adversely affected terrestrial and aquatic ecosystems in the Adirondacks and other areas of the region that are slowly recovering due to decreased emissions of N and sulfur oxides. Eutrophication in many estuaries within the region is projected to increase from greater storm runoff and less denitrification in riparian wetlands. Estuarine hypoxia may be exacerbated by increased stratification. Elevated water temperature favors algal species that produce harmful algal blooms (HABs). In several of the region's estuaries, HABs have been associated with bird die-offs. In the NA LCC region, amphibian populations appear to be declining. Some species may be adversely affected by GCC through higher temperatures and more frequent droughts. GCC may affect freshwater mussel populations via altered stream temperatures and increased sediment loading during heavy storms. Freshwater mussels are sensitive to un-ionized ammonia that more toxic at higher temperatures. We recommend studying the interactive effects of GCC on generation and bioavailability of methylmercury and how GCC-driven shifts in bird species distributions will affect avian exposure to methylmercury. Research is needed on how decreases in acid deposition concurrent with GCC will alter the structure and function of sensitive watersheds and surface waters. Studies are needed to determine how GCC will affect HABs and avian disease, and how more severe and extensive hypoxia will affect fish and shellfish populations. Regarding amphibians, we suggest research on 1) thermal tolerance and moisture requirements of species of concern, 2) effects of multiple stressors (temperature, desiccation, contaminants, nutrients), and 3) approaches to mitigate impacts of increased temperature and seasonal drought. We recommend studies to assess which mussel species and populations are vulnerable and which are resilient to rising stream temperatures, hydrological shifts, and ionic pollutants, all of which are influenced by GCC.
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Affiliation(s)
- Alfred E Pinkney
- US Fish and Wildlife Service, Chesapeake Bay Field Office, Annapolis, Maryland
| | - Charles T Driscoll
- Department of Civil and Environmental Engineering, Syracuse University, Syracuse, New York, USA
| | | | - Michael J Hooper
- Columbia Environmental Research Center, US Geological Survey, Columbia, Missouri
| | - Jeffrey Horan
- US Fish and Wildlife Service, Northeast Regional Office, Hadley, Massachusetts
| | - Jess W Jones
- US Fish and Wildlife Service, Virginia Tech University, Blacksburg, Virginia
| | - Rebecca S Lazarus
- Patuxent Wildlife Research Center, US Geological Survey, Beltsville, Maryland
| | - Harold G Marshall
- Department of Biological Sciences, Old Dominion University, Norfolk, Virginia, USA
| | - Andrew Milliken
- US Fish and Wildlife Service, Northeast Regional Office, Hadley, Massachusetts
| | - Barnett A Rattner
- Patuxent Wildlife Research Center, US Geological Survey, Beltsville, Maryland
| | - John Schmerfeld
- US Fish and Wildlife Service, Division of Refuges, Arlington, Virginia
| | - Donald W Sparling
- Department of Zoology, Southern Illinois University, Carbondale, Illinois, USA
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Landry JP, Hawkins C, Lee A, Coté A, Balaban E, Pompeiano M. Chick embryos have the same pattern of hypoxic lower-brain activation as fetal mammals. Dev Neurobiol 2015; 76:64-74. [DOI: 10.1002/dneu.22299] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Revised: 04/01/2015] [Accepted: 05/06/2015] [Indexed: 11/06/2022]
Affiliation(s)
- Jeremy P. Landry
- Department of Psychology; McGill University; Montreal Quebec Canada H3A 1B1
| | - Connor Hawkins
- Department of Psychology; McGill University; Montreal Quebec Canada H3A 1B1
| | - Aaron Lee
- Department of Psychology; McGill University; Montreal Quebec Canada H3A 1B1
| | - Alexandra Coté
- Department of Psychology; McGill University; Montreal Quebec Canada H3A 1B1
| | - Evan Balaban
- Department of Psychology; McGill University; Montreal Quebec Canada H3A 1B1
| | - Maria Pompeiano
- Department of Psychology; McGill University; Montreal Quebec Canada H3A 1B1
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104
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Rey S, Digka N, MacKenzie S. Animal Personality Relates to Thermal Preference in Wild-Type Zebrafish, Danio rerio. Zebrafish 2015; 12:243-9. [DOI: 10.1089/zeb.2014.1076] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Sonia Rey
- Autonomous University of Barcelona, Institute of Biotechnology and Biomedicine–IBB, Barcelona, Spain
- Institute of Aquaculture, University of Stirling, Stirling, United Kingdom
| | - Nikoletta Digka
- Autonomous University of Barcelona, Institute of Biotechnology and Biomedicine–IBB, Barcelona, Spain
| | - Simon MacKenzie
- Institute of Aquaculture, University of Stirling, Stirling, United Kingdom
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Vizin RCL, Scarpellini CDS, Ishikawa DT, Correa GM, de Souza CO, Gargaglioni LH, Carrettiero DC, Bícego KC, Almeida MC. TRPV4 activates autonomic and behavioural warmth-defence responses in Wistar rats. Acta Physiol (Oxf) 2015; 214:275-89. [PMID: 25739906 DOI: 10.1111/apha.12477] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Revised: 02/10/2015] [Accepted: 02/26/2015] [Indexed: 11/28/2022]
Abstract
AIM In this study, we aimed at investigating the involvement of the warmth-sensitive channel - TRPV4 (in vitro sensitive to temperatures in the range of approx. 24-34 °C) - on the thermoregulatory mechanisms in rats. METHODS We treated rats with a chemical selective agonist (RN-1747) and two antagonists (RN-1734 and HC-067047) of the TRPV4 channel and measured core body temperature, metabolism, heat loss index and preferred ambient temperature. RESULTS Our data revealed that chemical activation of TRPV4 channels by topical application of RN-1747 on the skin leads to hypothermia and this effect was blocked by the pre-treatment with the selective antagonist of this channel. Intracerebroventricular treatment with RN-1747 did not cause hypothermia, indicating that the observed response was indeed due to activation of TRPV4 channels in the periphery. Intravenous blockade of this channel with HC-067047 caused an increase in core body temperature at ambient temperature of 26 and 30 °C, but not at 22 and 32 °C. At 26 °C, HC-067047-induced hyperthermia was accompanied by increase in oxygen consumption (an index of thermogenesis), while chemical stimulation of TRPV4 increased tail heat loss, indicating that these two autonomic thermoeffectors in the rat are modulated through TRPV4 channels. Furthermore, rats chemically stimulated with TRPV4 agonist choose colder ambient temperatures and cold-seeking behaviour after thermal stimulation (28-31 °C) was inhibited by TRPV4 antagonist. CONCLUSION Our results suggest, for the first time, that TRPV4 channel is involved in the recruitment of behavioural and autonomic warmth-defence responses to regulate core body temperature.
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Affiliation(s)
- R. C. L. Vizin
- Graduate Program on Neuroscience and Cognition; Universidade Federal do ABC (UFABC); São Bernardo do Campo SP Brazil
| | - C. da S. Scarpellini
- Department of Animal Morphology and Physiology; College of Agricultural and Veterinary Sciences; São Paulo State University; Jaboticabal SP Brazil
- Joint UFSCar-UNESP Graduate Program of Physiological Sciences; Sao Carlos SP Brazil
- National Institute of Science and Technology in Comparative Physiology (INCT - Fisiologia Comparada); Jaboticabal SP Brazil
| | - D. T. Ishikawa
- Graduate Program on Neuroscience and Cognition; Universidade Federal do ABC (UFABC); São Bernardo do Campo SP Brazil
| | - G. M. Correa
- Department of Animal Morphology and Physiology; College of Agricultural and Veterinary Sciences; São Paulo State University; Jaboticabal SP Brazil
- National Institute of Science and Technology in Comparative Physiology (INCT - Fisiologia Comparada); Jaboticabal SP Brazil
| | - C. O. de Souza
- Graduate Program on Neuroscience and Cognition; Universidade Federal do ABC (UFABC); São Bernardo do Campo SP Brazil
| | - L. H. Gargaglioni
- Department of Animal Morphology and Physiology; College of Agricultural and Veterinary Sciences; São Paulo State University; Jaboticabal SP Brazil
- National Institute of Science and Technology in Comparative Physiology (INCT - Fisiologia Comparada); Jaboticabal SP Brazil
| | - D. C. Carrettiero
- Graduate Program on Neuroscience and Cognition; Universidade Federal do ABC (UFABC); São Bernardo do Campo SP Brazil
- Natural and Humanities Science Center; Universidade Federal do ABC (UFABC); São Bernardo do Campo SP Brazil
| | - K. C. Bícego
- Department of Animal Morphology and Physiology; College of Agricultural and Veterinary Sciences; São Paulo State University; Jaboticabal SP Brazil
- National Institute of Science and Technology in Comparative Physiology (INCT - Fisiologia Comparada); Jaboticabal SP Brazil
| | - M. C. Almeida
- Graduate Program on Neuroscience and Cognition; Universidade Federal do ABC (UFABC); São Bernardo do Campo SP Brazil
- Natural and Humanities Science Center; Universidade Federal do ABC (UFABC); São Bernardo do Campo SP Brazil
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106
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Shine R, Amiel J, Munn AJ, Stewart M, Vyssotski AL, Lesku JA. Is "cooling then freezing" a humane way to kill amphibians and reptiles? Biol Open 2015; 4:760-3. [PMID: 26015533 PMCID: PMC4571096 DOI: 10.1242/bio.012179] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
What is the most humane way to kill amphibians and small reptiles that are used in research? Historically, such animals were often killed by cooling followed by freezing, but this method was outlawed by ethics committees because of concerns that ice-crystals may form in peripheral tissues while the animal is still conscious, putatively causing intense pain. This argument relies on assumptions about the capacity of such animals to feel pain, the thermal thresholds for tissue freezing, the temperature-dependence of nerve-impulse transmission and brain activity, and the magnitude of thermal differentials within the bodies of rapidly-cooling animals. A review of published studies casts doubt on those assumptions, and our laboratory experiments on cane toads (Rhinella marina) show that brain activity declines smoothly during freezing, with no indication of pain perception. Thus, cooling followed by freezing can offer a humane method of killing cane toads, and may be widely applicable to other ectotherms (especially, small species that are rarely active at low body temperatures). More generally, many animal-ethics regulations have little empirical basis, and research on this topic is urgently required in order to reduce animal suffering.
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Affiliation(s)
- Richard Shine
- School of Biological Sciences A08, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Joshua Amiel
- School of Biological Sciences A08, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Adam J Munn
- Institute for Conservation Biology and Environmental Management, School of Biological Sciences, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - Mathew Stewart
- Institute for Conservation Biology and Environmental Management, School of Biological Sciences, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - Alexei L Vyssotski
- Institute of Neuroinformatics, University of Zurich/ETH Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
| | - John A Lesku
- School of Life Sciences, La Trobe University, Melbourne, Victoria 3086, Australia
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107
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Acute and chronic temperature effects on cardiovascular regulation in the red-eared slider (Trachemys scripta). J Comp Physiol B 2015; 185:401-11. [PMID: 25774046 DOI: 10.1007/s00360-015-0896-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Revised: 02/13/2015] [Accepted: 02/27/2015] [Indexed: 10/23/2022]
Abstract
Acute and chronic changes in ambient temperature alter several aspects of reptilian physiology. We investigated the effects of each type of temperature change on reptilian cardiovascular regulation in red-eared slider turtles (Trachemys scripta), a species known to experience marked seasonal changes in ambient temperature. Turtles were instrumented with occlusive catheters in the femoral artery and vein. Following an acclimation period of 10 days at 13 °C (13(1)), cardiovascular responses to adrenaline, and the cardiac limb of the baroreflex were quantified. Ambient temperature was then reduced 1 °C day(-1) until 3 °C was reached (3(1)). Turtles were maintained at this temperature for 1-week before cardiovascular responses were reassessed. Turtles were then gradually (1 °C day(-1)) returned to an ambient temperature of 13 °C, (13(2)). After a 1-week re-acclimation period, cardiovascular responses were again determined. Finally, 1-week post-pharmacological manipulation of turtles in the 13(2) treatment, ambient temperature was reduced to 3 °C over 24 h (3(2)), and cardiovascular responses were again assessed. Temperature reduction from 13(1) to 3(1) decreased mean arterial blood pressure (P(m)) and heart rate (f(H)) by ~38 and ~63%, respectively. Acute temperature reduction, from 13(2) to 3(2), decreased f(H) similarly, ~66%; however, while P(m) decreased ~28%, this was not significantly different than P(m) at 13(2). The adrenaline injections increased f(H) ranging from 90 to 170% at 13 °C which was a greater change than that observed at 3 °C ranging from a 40 to 70% increase. The increase in P m at the lowest dose of adrenaline did not differ across the temperature treatment groups. The operational point (set-point) P(m) of the baroreflex was decreased similarly by both methods of temperature reduction (3(1) or 3(2)). Further, a hypertensive cardiac baroreflex was absent in the majority of the animals studied independent of temperature. Baroreflex gain and normalized gain based on individual estimates of the relationship were decreased by temperature reduction similarly. Collectively, the data suggest that red-eared slider turtles modulate (down-regulate) some cardiovascular control mechanisms during reduced ambient temperature.
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108
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Temperature effects on baroreflex control of heart rate in the toad, Rhinella schneideri. Comp Biochem Physiol A Mol Integr Physiol 2015; 179:81-8. [DOI: 10.1016/j.cbpa.2014.09.027] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Revised: 09/01/2014] [Accepted: 09/18/2014] [Indexed: 11/24/2022]
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109
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Fonseca EM, Dias MB, Bícego KC, Gargaglioni LH. Orexin in the toad Rhinella schneideri: The location of orexinergic neurons and the role of orexin in ventilatory responses to hypercarbia and hypoxia. Respir Physiol Neurobiol 2014; 224:90-9. [PMID: 25434286 DOI: 10.1016/j.resp.2014.11.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Revised: 11/03/2014] [Accepted: 11/20/2014] [Indexed: 01/24/2023]
Abstract
Recent reports have suggested that orexins, also known as hypocretins, play an important role in the modulation of respiratory control in mammals, but there are no data available describing the role of the orexinergic system in the peripheral and central chemoreception of non-mammalian vertebrates. Therefore, the present study was designed to examine the localization of orexin-immunoreactive neurons in the brain of toads (Rhinella schneideri) and to investigate the contribution of orexin receptor-1 (OX1R) to the hypoxic and hypercarbic ventilatory responses of these animals during light and dark phases. Our results demonstrated that the orexinergic neurons of R. schneideri are located in the suprachiasmatic nucleus of the diencephalon. Additionally, the intracerebroventricular injection of SB-334867 (OX1R selective antagonist) attenuated the ventilatory response to hypercarbia during the dark phase by acting on tidal volume and breathing frequency, while during the light phase, SB-334867 attenuated the ventilatory response to hypoxia by acting on tidal volume only. We conclude that in the toad R. schneideri, orexinergic neurons are located in the suprachiasmatic nucleus and that OX1R contributes to hypercarbic and hypoxic chemoreflexes.
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Affiliation(s)
- Elisa M Fonseca
- Department of Animal Morphology and Physiology, Sao Paulo State University-UNESP FCAV at Jaboticabal, SP, Brazil
| | - Mirela B Dias
- Department of Physiology, Institute of Bioscience, Sao Paulo State University-UNESP, Botucatu, SP, Brazil
| | - Kênia C Bícego
- Department of Animal Morphology and Physiology, Sao Paulo State University-UNESP FCAV at Jaboticabal, SP, Brazil
| | - Luciane H Gargaglioni
- Department of Animal Morphology and Physiology, Sao Paulo State University-UNESP FCAV at Jaboticabal, SP, Brazil.
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110
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Dzialowski EM, Tattersall GJ, Nicol SC, Frappell PB. Fluctuations in oxygen influence facultative endothermy in bumblebees. J Exp Biol 2014; 217:3834-42. [DOI: 10.1242/jeb.107052] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Bumblebees are facultative endotherms, having the ability to elevate thorax temperature above ambient temperature by elevating metabolism. Here, we investigated the influence of hypoxia on metabolic demands and thermoregulatory capabilities of the bumblebee Bombus terrestris. We measured thorax temperature, rates of oxygen consumption and carbon dioxide production, and abdominal pumping rates of bees randomly exposed to oxygen levels of 20, 15, 10 and 5 kPa at 26°C. Under normoxia, bumblebees maintained an elevated mean thorax temperature of 35.5°C. There was no significant change in thorax temperature at 15 kPa O2 (33.4°C). Mean thorax temperature decreased significantly at 10 kPa O2 (31.6°C) and 5 kPa O2 (27.3°C). Bees were able to maintain an elevated metabolic rate at 15 and 10 kPa O2. In normoxia, endothermic bees exhibited periods of rapid abdominal pumping (327 min−1) interspaced by periods of no abdominal pumping. At 10 kPa O2, abdominal pumping rate decreased (255 min−1) but became more continuous. Upon exposure to 5 kPa, metabolic rate and abdominal pumping rate (152 min−1) decreased, although the animals continued abdominal pumping at the reduced rate throughout the exposure period. Bumblebees are able to meet the energetic demands of endothermy at 15 kPa O2, but become compromised at levels of 10 kPa O2 and below.
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Affiliation(s)
- Edward M. Dzialowski
- Developmental Integrative Biology Cluster, Department of Biological Sciences, University of North Texas, Denton, TX 76203, USA
| | - Glenn J. Tattersall
- Department of Biological Sciences, Brock University, St Catharines, ON, Canada, L2S 3A1
| | - Stewart C. Nicol
- School of Biological Sciences, University of Tasmania, Hobart, TAS 7005, Australia
| | - Peter B. Frappell
- Institute of Marine and Antarctic Studies, University of Tasmania, Hobart, TAS 7005, Australia
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111
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Lei J, Booth DT. Temperature, field activity and post-feeding metabolic response in the Asian house gecko, Hemidactylus frenatus. J Therm Biol 2014; 45:175-80. [DOI: 10.1016/j.jtherbio.2014.09.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Revised: 08/28/2014] [Accepted: 09/17/2014] [Indexed: 10/24/2022]
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112
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Cortés PA, Franco M, Moreno-Gómez FN, Barrientos K, Nespolo RF. Thermoregulatory capacities and torpor in the South American marsupial, Dromiciops gliroides. J Therm Biol 2014; 45:1-8. [DOI: 10.1016/j.jtherbio.2014.07.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Revised: 07/03/2014] [Accepted: 07/03/2014] [Indexed: 10/25/2022]
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113
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Branco LG, Soriano RN, Steiner AA. Gaseous Mediators in Temperature Regulation. Compr Physiol 2014; 4:1301-38. [DOI: 10.1002/cphy.c130053] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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114
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Espinha LP, Souza FA, Capalbo AC, Bícego KC, Macari M, Gargaglioni LH. Age and gender influence the cardiorespiratory function and metabolic rate of broiler chicks during normocapnia and hypercapnia. Respir Physiol Neurobiol 2014; 200:50-6. [DOI: 10.1016/j.resp.2014.05.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Revised: 05/26/2014] [Accepted: 05/29/2014] [Indexed: 01/26/2023]
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115
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Lopes LT, Biancardi V, Vieira EB, Leite-Panissi C, Bícego KC, Gargaglioni LH. Participation of the dorsal periaqueductal grey matter in the hypoxic ventilatory response in unanaesthetized rats. Acta Physiol (Oxf) 2014; 211:528-37. [PMID: 24612700 DOI: 10.1111/apha.12254] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Revised: 12/09/2013] [Accepted: 01/24/2014] [Indexed: 11/28/2022]
Abstract
AIM Although periaqueductal grey matter activation is known to elicit respiratory and cardiovascular responses, the role of this midbrain area in the compensatory responses to hypoxia is still unknown. To test the participation of the periaqueductal grey matter in cardiorespiratory and thermal responses to hypoxia in adult male Wistar rats, we performed a chemical lesion of the dorsolateral/dorsomedial or the ventrolateral/lateral periaqueductal grey matter using ibotenic acid. METHODS Pulmonary ventilation, mean arterial pressure, heart rate and body temperature were measured in unanaesthetized rats during normoxic and hypoxic exposure (5, 15, 30 min, 7% O2). RESULTS An ibotenic acid lesion of the dorsolateral/dorsomedial periaqueductal grey matter caused a higher increase in pulmonary ventilation (67.1%, 1730±282.5 mL kg(-1) min(-1)) compared to the Sham group (991.4±194 mL kg(-1) min(-1)) after 15 min in hypoxia, whereas for the ventrolateral/Lateral periaqueductal grey matter lesion, no differences were observed between groups. Mean arterial pressure, heart rate and body temperature were not affected by a dorsolateral/dorsomedial or ventrolateral/lateral periaqueductal grey matter lesion. CONCLUSION Middle to caudal portions of the dorsolateral/dorsomedial periaqueductal grey matter neurones modulate the hypoxic ventilatory response, exerting an inhibitory modulation during low O2 situations. In addition, the middle to caudal portions of the dorsolateral/dorsomedial or ventrolateral/lateral periaqueductal grey matter do not appear to exert a tonic role on cardiovascular or thermal parameters during normoxic and hypoxic conditions.
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Affiliation(s)
- L. T. Lopes
- Department of Animal Morphology and Physiology; São Paulo State University (FCAV/UNESP); Jaboticabal SP Brazil
| | - V. Biancardi
- Department of Animal Morphology and Physiology; São Paulo State University (FCAV/UNESP); Jaboticabal SP Brazil
| | - E. B. Vieira
- Department of Morphology, Physiology and Basic Pathology; Dental School of Ribeirao Preto; University of São Paulo (USP); RibeirãoPreto SP Brazil
| | - C. Leite-Panissi
- Department of Morphology, Physiology and Basic Pathology; Dental School of Ribeirao Preto; University of São Paulo (USP); RibeirãoPreto SP Brazil
| | - K. C. Bícego
- Department of Animal Morphology and Physiology; São Paulo State University (FCAV/UNESP); Jaboticabal SP Brazil
| | - L. H. Gargaglioni
- Department of Animal Morphology and Physiology; São Paulo State University (FCAV/UNESP); Jaboticabal SP Brazil
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117
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Thermogenesis, vocalization, and temperature preference of 1-day-old chicken hatchlings after cold-exposure in late embryogenesis. J Comp Physiol B 2014; 184:631-9. [DOI: 10.1007/s00360-014-0828-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Revised: 03/10/2014] [Accepted: 04/01/2014] [Indexed: 10/25/2022]
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118
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Effects of lake warming on behavioural thermoregulatory tactics in a cold-water stenothermic fish. PLoS One 2014; 9:e92514. [PMID: 24663489 PMCID: PMC3963910 DOI: 10.1371/journal.pone.0092514] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Accepted: 02/24/2014] [Indexed: 11/19/2022] Open
Abstract
Despite some evidence of within-population phenotypic variation in fish thermal behaviour, the occurrence of alternative tactics of this behaviour is rarely explicitly considered when studying natural populations. Brook charr provide an example of within-population variability in behavioural thermoregulation as revealed by a recent study on a lacustrine population of this species. The objectives of the present study were (i) to determine the influence of natural variability in the lake's thermal profiles on the expression of thermoregulatory tactics, and (ii) to determine the vertical and horizontal movements of individuals at different periods of the day to better understand the spatio-temporal behaviour associated with each thermoregulatory tactic. During summer 2010, 30 adult brook charr were equipped with thermo-sensitive radio transmitters to monitor their selected temperatures and daily movements. These individuals exhibited the same four behavioural thermoregulatory tactics observed in 2003 and 2005, but the expression of two of these was weaker in 2010. This result was associated with lake warming, which constrained the expression of two thermoregulatory tactics: brook charr significantly decreased their selected temperatures and daily movements when the mean daily epilimnion temperature was above 22.4°C. This study shows for the first time that the expression of behavioural thermoregulatory tactics is related to the lake's thermal regime and that the tactics are plastic through time.
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119
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Lutaif NA, Palazzo R, Gontijo JAR. Early detection of metabolic and energy disorders by thermal time series stochastic complexity analysis. Braz J Med Biol Res 2014; 47:70-9. [PMID: 24519093 PMCID: PMC3932975 DOI: 10.1590/1414-431x20133097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Accepted: 08/06/2013] [Indexed: 11/22/2022] Open
Abstract
Maintenance of thermal homeostasis in rats fed a high-fat diet (HFD) is
associated with changes in their thermal balance. The thermodynamic relationship
between heat dissipation and energy storage is altered by the ingestion of
high-energy diet content. Observation of thermal registers of core temperature
behavior, in humans and rodents, permits identification of some characteristics
of time series, such as autoreference and stationarity that fit adequately to a
stochastic analysis. To identify this change, we used, for the first time, a
stochastic autoregressive model, the concepts of which match those associated
with physiological systems involved and applied in male HFD rats compared with
their appropriate standard food intake age-matched male controls (n=7 per
group). By analyzing a recorded temperature time series, we were able to
identify when thermal homeostasis would be affected by a new diet. The
autoregressive time series model (AR model) was used to predict the occurrence
of thermal homeostasis, and this model proved to be very effective in
distinguishing such a physiological disorder. Thus, we infer from the results of
our study that maximum entropy distribution as a means for stochastic
characterization of temperature time series registers may be established as an
important and early tool to aid in the diagnosis and prevention of metabolic
diseases due to their ability to detect small variations in thermal profile.
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Affiliation(s)
- N A Lutaif
- Universidade Estadual de Campinas, Faculdade de Ciências Médicas, Departamento de Clínica Médica, CampinasSP, Brasil
| | - R Palazzo
- Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e Computação, Departamento de Telemática, CampinasSP, Brasil
| | - J A R Gontijo
- Universidade Estadual de Campinas, Faculdade de Ciências Médicas, Departamento de Clínica Médica, CampinasSP, Brasil
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Reeve AJ, Ojanguren AF, Deacon AE, Shimadzu H, Ramnarine IW, Magurran AE. Interplay of temperature and light influences wild guppy (Poecilia reticulata) daily reproductive activity. Biol J Linn Soc Lond 2014. [DOI: 10.1111/bij.12217] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Al J. Reeve
- Scottish Oceans Institute; University of St Andrews; St Andrews KY16 8LB UK
| | | | - Amy E. Deacon
- Scottish Oceans Institute; University of St Andrews; St Andrews KY16 8LB UK
| | - Hideyasu Shimadzu
- Scottish Oceans Institute; University of St Andrews; St Andrews KY16 8LB UK
- Department of Mathematics; Keio University; Yokohama Japan
| | | | - Anne E. Magurran
- Scottish Oceans Institute; University of St Andrews; St Andrews KY16 8LB UK
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121
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Abstract
In mammals and birds, all oxygen used (VO2) must pass through the lungs; hence, some degree of coupling between VO2 and pulmonary ventilation (VE) is highly predictable. Nevertheless, VE is also involved with CO2 elimination, a task that is often in conflict with the convection of O2. In hot or cold conditions, the relationship between VE and VO2 includes the participation of the respiratory apparatus to the control of body temperature and water balance. Some compromise among these tasks is achieved through changes in breathing pattern, uncoupling changes in alveolar ventilation from VE. This article examines primarily the relationship between VE and VO2 under thermal stimuli. In the process, it considers how the relationship is influenced by hypoxia, hypercapnia or changes in metabolic level. The shuffling of tasks in emergency situations illustrates that the constraints on VE-VO2 for the protection of blood gases have ample room for flexibility. However, when other priorities do not interfere with the primary goal of gas exchange, VE follows metabolic rate quite closely. The fact that arterial CO2 remains stable when metabolism is changed by the most diverse circumstances (moderate exercise, cold, cold and exercise combined, variations in body size, caloric intake, age, time of the day, hormones, drugs, etc.) makes it unlikely that VE and metabolism are controlled in parallel by the condition responsible for the metabolic change. Rather, some observations support the view that the gaseous component of metabolic rate, probably CO2, may provide the link between the metabolic level and VE.
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122
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Frequent yawning as an initial signal of fever relief. Med Hypotheses 2013; 81:1034-5. [DOI: 10.1016/j.mehy.2013.09.026] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Accepted: 09/18/2013] [Indexed: 11/18/2022]
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123
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Garina DV, Smirnov AK, Kuz'mina V. The long-term effect of serotonin on the thermoregulatory behavior in juvenile cyprinidae (Cyprinus carpio and Carassius auratus). FISH PHYSIOLOGY AND BIOCHEMISTRY 2013; 39:1373-1376. [PMID: 23515758 DOI: 10.1007/s10695-013-9791-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2012] [Accepted: 03/12/2013] [Indexed: 06/01/2023]
Abstract
The effect of serotonin after intracerebroventricular (ICV) injections in dosage of 0.3 and 0.15 μg/g of the body weight on the thermoregulatory behavior in juvenile carp Cyprinus carpio L. and goldfish Carassius auratus (L.) has been studied in two experiments of 10- to 11-day duration. It has been found that ICV injection of serotonin in dosage of 0.3 μg/g caused the initial decrease in preferred temperatures (PT) (2-3 days) followed by their further increase (4-8 days after the administration) in carp. ICV injection of serotonin in dosage of 0.15 μg/g caused more durable initial decrease in PT (2-8 days) followed by the increase of once (9-11 days of observation) in goldfish. The values of the ultimate preferred temperature in fish of the experimental group exceeded that in control specimens by 4.1 °C at the first experiment and by 3.1 °C in the second experiment. The data for the first time demonstrated long-term effect of a single ICV injection of serotonin on the thermoregulatory behavior in two closely related species of teleosts.
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Affiliation(s)
- D V Garina
- I.D. Papanin Institute for Biology of Inland Waters, Russian Academy of Sciences, Borok, Yaroslavl, Russia,
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124
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Carter A, DuRant S, Hepp G, Hopkins W. Thermal Challenge Severity Differentially Influences Wound Healing in Wood Duck (Aix sponsa) Ducklings. ACTA ACUST UNITED AC 2013; 319:422-9. [DOI: 10.1002/jez.1805] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2012] [Revised: 12/27/2012] [Accepted: 04/18/2013] [Indexed: 11/09/2022]
Affiliation(s)
- A.W. Carter
- Department of Fish and Wildlife Conservation; Blacksburg; Virginia
| | - S.E. DuRant
- Department of Fish and Wildlife Conservation; Blacksburg; Virginia
| | - G.R. Hepp
- School of Forestry and Wildlife Sciences; Auburn; Alabama
| | - W.A. Hopkins
- Department of Fish and Wildlife Conservation; Blacksburg; Virginia
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125
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Reiser S, Temming A, Eckhardt A, Herrmann JP. Automation and critical evaluation of an annular chamber for aquatic ectotherm temperature preference experiments. Methods Ecol Evol 2013. [DOI: 10.1111/2041-210x.12045] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- Stefan Reiser
- Institute for Hydrobiology and Fisheries Science; University of Hamburg; Olbersweg 24 22767 Hamburg Germany
- Thünen-Institute of Fisheries Ecology; Palmaille 9 22767 Hamburg Germany
| | - Axel Temming
- Institute for Hydrobiology and Fisheries Science; University of Hamburg; Olbersweg 24 22767 Hamburg Germany
| | - André Eckhardt
- Institute for Hydrobiology and Fisheries Science; University of Hamburg; Olbersweg 24 22767 Hamburg Germany
| | - Jens-Peter Herrmann
- Institute for Hydrobiology and Fisheries Science; University of Hamburg; Olbersweg 24 22767 Hamburg Germany
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126
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He J, Xiu M, Tang X, Wang N, Xin Y, Li W, Chen Q. Thermoregulatory and metabolic responses to hypoxia in the oviparous lizard, Phrynocephalus przewalskii. Comp Biochem Physiol A Mol Integr Physiol 2013; 165:207-13. [PMID: 23500623 DOI: 10.1016/j.cbpa.2013.03.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2012] [Revised: 02/08/2013] [Accepted: 03/05/2013] [Indexed: 11/25/2022]
Abstract
The effects of hypoxia on behavioral thermoregulation, rate of heating and cooling, hysteresis of heart rate, and standard metabolic rate (SMR) were investigated in Phrynocephalus przewalskii, a small size toad headed lizard. Preferred temperature (T(b)) descended when lizards were exposed to severe hypoxia (8% O(2) and 6% O(2)) for 22 h, and lizards were able to maintain preferred T(b) after one week at 12% and 8% O(2) respectively. The period of heating increased after being treated with hypoxia (12% and 8% O(2)) for one week. Hysteresis of heart rate appeared at any given body temperature and oxygen level except at 39 °C and 40 °C at 8% O(2). SMR significantly increased after one-week acclimatization to 12% and 8% O(2) when ambient temperature (T(a)) was 25 °C, however, it did not change at 35 °C. Thus, we suggest that P. przewalskii has special thermoregulatory and metabolic mechanisms to acclimatize to the hypoxic environment.
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Affiliation(s)
- Jianzheng He
- Institute of Biochemistry and Molecular Biology, School of Life Sciences, Lanzhou University, 222 Tianshui South Road, Lanzhou, 730000, PR China
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Seeland A, Albrand J, Oehlmann J, Müller R. Life stage-specific effects of the fungicide pyrimethanil and temperature on the snail Physella acuta (Draparnaud, 1805) disclose the pitfalls for the aquatic risk assessment under global climate change. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2013; 174:1-9. [PMID: 23246620 DOI: 10.1016/j.envpol.2012.10.020] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2012] [Revised: 10/08/2012] [Accepted: 10/10/2012] [Indexed: 06/01/2023]
Abstract
It can be suggested that the combined stress of pesticide pollution and suboptimal temperature influences the sensitivity of life stages of aquatic invertebrates differently. The embryo, juvenile, half- and full-life-cycle toxicity tests performed with the snail Physella acuta at different concentrations (0.06-0.5 or 1.0 mg L(-1)) of the model fungicide pyrimethanil at 15, 20 and 25 °C revealed, that pyrimethanil caused concentration-dependent effects at all test temperatures. Interestingly, the ecotoxicity of pyrimethanil was higher at lower (suboptimal) temperature for embryo hatching and F(1) reproduction, but its ecotoxicity for juvenile growth and F(0) reproduction increased with increasing temperature. The life-stage specific temperature-dependent ecotoxicity of pyrimethanil and the high fungicide susceptibility of the invasive snail clearly demonstrate the complexity of pesticide-temperature interactions and the challenge to draw conclusions for the risk of pesticides under the impact of global climate change.
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Affiliation(s)
- Anne Seeland
- Goethe University Frankfurt am Main, Department Aquatic Ecotoxicology, Max-von-Laue-Strasse 13, D-60438 Frankfurt, Germany.
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128
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Gallup AC, Eldakar OT. The thermoregulatory theory of yawning: what we know from over 5 years of research. Front Neurosci 2013; 6:188. [PMID: 23293583 PMCID: PMC3534187 DOI: 10.3389/fnins.2012.00188] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Accepted: 12/06/2012] [Indexed: 01/24/2023] Open
Abstract
Over the past 5 years numerous reports have confirmed and replicated the specific brain cooling and thermal window predictions derived from the thermoregulatory theory of yawning, and no study has found evidence contrary to these findings. Here we review the comparative research supporting this model of yawning among homeotherms, while highlighting a recent report showing how the expression of contagious yawning in humans is altered by seasonal climate variation. The fact that yawning is constrained to a thermal window of ambient temperature provides unique and compelling support in favor of this theory. Heretofore, no existing alternative hypothesis of yawning can explain these results, which have important implications for understanding the potential functional role of this behavior, both physiologically and socially, in humans and other animals. In discussion we stress the broader applications of this work in clinical settings, and counter the various criticisms of this theory.
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Affiliation(s)
- Andrew C. Gallup
- Department of Ecology and Evolutionary Biology, Princeton UniversityPrinceton, NJ, USA
| | - Omar T. Eldakar
- Center for Insect Science, University of ArizonaTucson, AZ, USA
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129
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130
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Tattersall GJ, Tyson TM, Lenchyshyn JR, Carlone RL. Temperature preference during forelimb regeneration in the red-spotted newt Notophthalmus viridescens. ACTA ACUST UNITED AC 2012; 317:248-58. [PMID: 22539209 DOI: 10.1002/jez.1719] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Red-spotted newts (Notophthalmus viridescens) are model organisms for regenerative research. These animals can regenerate limbs, tails, jaws, spinal cords, as well as the lens of the eye. Newts are small ectotherms that are aquatic as adults; as ectotherms, they naturally conform to the temperature of their surroundings. Environmental temperatures, however, can increase or decrease the red-spotted newt's metabolic processes, including their rate of tissue regeneration; whether an optimal temperature for this rate of regeneration exists is unknown. However, newts do exhibit behavioral preferences for certain temperatures, and these thermal preferences can change with season or with acclimation. Given this flexibility in behavioral thermoregulation, we hypothesized that the process of tissue regeneration could also affect thermal preference, given the metabolic costs or altered temperature sensitivities of tissue regrowth. It was predicted that regenerating newts would select an environmental temperature that maximized the rate of regeneration, however, this prediction was not fully supported. Thermal preference trials revealed that newts consistently selected temperatures between 24 and 25°C throughout regeneration. This temperature selection was warmer than that of uninjured conspecifics, but was lower than temperatures that would have further augmented the rate of regeneration. Interestingly, regenerating newts maintained a more stable temperature preference than sham newts, suggesting that accuracy in thermoregulation may be more important to regenerating individuals, than to noninjured individuals.
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Affiliation(s)
- Glenn J Tattersall
- Department of Biological Sciences, Brock University, St. Catharines, Ontario, Canada.
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131
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The effect of thermopreference on circadian thermoregulation in sprague-dawley and fisher 344 rats. J Therm Biol 2012. [DOI: 10.1016/j.jtherbio.2011.09.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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132
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Interaction of hypoxia and core temperature: potential role of TRPV1. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 758:173-8. [PMID: 23080159 DOI: 10.1007/978-94-007-4584-1_24] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Hypoxia exposure in small mammals elicits an initial rise in ventilation followed by a reduction to levels that are often less than the normoxic value. The fall in ventilation is matched by a decrease in metabolism rate and a reduction in core body temperature (Tb). The transient receptor potential vanilloid 1 (TRPV1) ion channel has been implicated in thermoregulation (Caterina et al., Science 288:306-313, 2000) and recently shown to exert a tonic effect on Tb in human subjects (Gavva et al., Pain 136:202-210, 2008). We review herein the hypothesis that TRPV1 modulates the Tb response to hypoxia. We provide preliminary evidence that a 24 h hypoxia (FIO(2)=0.1) exposure caused an enhanced decrease in Tb in mutant TRPV1(-/-) mice compared to the TRPV1(+/+) genotype (Tb was » 1°C lower than TRPV1(+/+)). Further investigation is warranted to determine the extent of TRPV1 ion channel involvement in acute and adaptive responses to hypoxia.
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133
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Soriano RN, Nicoli LG, Carnio EC, Branco LGS. Exogenous ghrelin attenuates endotoxin fever in rats. Peptides 2011; 32:2372-6. [PMID: 21377501 DOI: 10.1016/j.peptides.2011.02.019] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2011] [Revised: 02/18/2011] [Accepted: 02/20/2011] [Indexed: 11/30/2022]
Abstract
Ghrelin is a gut-derived peptide that plays a role in energy homeostasis. Recent studies have implicated ghrelin in systemic inflammation, showing increased plasma ghrelin levels after endotoxin (lipopolysaccharide, LPS) administration. The aims of this study were (1) to test the hypothesis that ghrelin administration affects LPS-induced fever; and (2) to assess the putative effects of ghrelin on plasma corticosterone secretion and preoptic region prostaglandin (PG) E(2) levels in euthermic and febrile rats. Rats were implanted with a temperature datalogger capsule in the peritoneal cavity to record body core temperature. One week later, they were challenged with LPS (50 μg/kg, intraperitoneal, i.p.) alone or combined with ghrelin (0.1mg/kg, i.p.). In another group of rats, plasma corticosterone and preoptic region PGE(2) levels were measured 2h after injections. In euthermic animals, systemic administration of ghrelin failed to elicit any thermoregulatory effect, and caused no significant changes in basal plasma corticosterone and preoptic region PGE(2) levels. LPS caused a typical febrile response, accompanied by increased plasma corticosterone and preoptic PGE(2) levels. When LPS administration was combined with ghrelin fever was attenuated, corticosterone secretion further increased, and the elevated preoptic PGE(2) levels were relatively reduced, but a correlation between these two variables (corticosterone and PGE(2)) failed to exist. The present data add ghrelin to the neurochemical milieu controlling the immune/thermoregulatory system acting as an antipyretic molecule. Moreover, our findings also support the notion that ghrelin attenuates fever by means of a direct effect of the peptide reducing PGE(2) production in the preoptic region.
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Affiliation(s)
- Renato N Soriano
- Nursing School of Ribeirão Preto, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
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134
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Clapham JC. Central control of thermogenesis. Neuropharmacology 2011; 63:111-23. [PMID: 22063719 DOI: 10.1016/j.neuropharm.2011.10.014] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2011] [Revised: 10/18/2011] [Accepted: 10/24/2011] [Indexed: 01/26/2023]
Abstract
In mammals and birds, conservation of body heat at around 37 °C is vital to life. Thermogenesis is the production of this heat which can be obligatory, as in basal metabolic rate, or it can be facultative such as the response to cold. A complex regulatory system has evolved which senses environmental or core temperature and integrates this information in hypothalamic regions such as the preoptic area and dorsomedial hypothalamus. These areas then send the appropriate signals to generate and conserve heat (or dissipate it). In this review, the importance of the sympathetic nervous system is discussed in relation to its role in basal metabolic rate and adaptive thermogenesis with a particular emphasis to human obesity. The efferent sympathetic pathway does not uniformly act on all tissues; different tissues can receive different levels of sympathetic drive at the same time. This is an important concept in the discussion of the pharmacotherapy of obesity. Despite decades of work the medicine chest contains only one pill for the long term treatment of obesity, orlistat, a lipase inhibitor that prevents the absorption of lipid from the gut and is itself not systemically absorbed. The central controlling system for thermogenesis has many potential intervention points. Several drugs, previously marketed, awaiting approval or in the earlier stages of development may have a thermogenic effect via activation of the sympathetic nervous system at some point in the thermoregulatory circuit and are discussed in this review. If the balance is weighted to the "wrong" side there is the burden of increased cardiovascular risk while a shift to the "right" side, if possible, will afford a thermogenic benefit that is conducive to weight loss maintenance. This article is part of a Special Issue entitled 'Central Control Food Intake'
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Affiliation(s)
- John C Clapham
- AstraZeneca R&D, Alderley Park, Macclesfield, SK10 4TG, UK.
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135
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Behavioural thermoregulatory tactics in lacustrine brook charr, Salvelinus fontinalis. PLoS One 2011; 6:e18603. [PMID: 21490935 PMCID: PMC3072417 DOI: 10.1371/journal.pone.0018603] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2010] [Accepted: 03/10/2011] [Indexed: 11/19/2022] Open
Abstract
The need to vary body temperature to optimize physiological processes can lead to thermoregulatory behaviours, particularly in ectotherms. Despite some evidence of within-population phenotypic variation in thermal behaviour, the occurrence of alternative tactics of this behaviour is rarely explicitly considered when studying natural populations. The main objective of this study was to determine whether different thermal tactics exist among individuals of the same population. We studied the behavioural thermoregulation of 33 adult brook charr in a stratified lake using thermo-sensitive radio transmitters that measured hourly individual temperature over one month. The observed behavioural thermoregulatory patterns were consistent between years and suggest the existence of four tactics: two “warm” tactics with both crepuscular and finer periodicities, with or without a diel periodicity, and two “cool” tactics, with or without a diel periodicity. Telemetry data support the above findings by showing that the different tactics are associated with different patterns of diel horizontal movements. Taken together, our results show a clear spatio-temporal segregation of individuals displaying different tactics, suggesting a reduction of niche overlap. To our knowledge, this is the first study showing the presence of behavioural thermoregulatory tactics in a vertebrate.
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136
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Behavioral thermoregulation, temperature tolerance and oxygen consumption in the Mexican bullseye puffer fish, Sphoeroides annulatus Jenyns (1842), acclimated to different temperatures. J Therm Biol 2011. [DOI: 10.1016/j.jtherbio.2011.03.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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137
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Coggan N, Clissold FJ, Simpson SJ. Locusts use dynamic thermoregulatory behaviour to optimize nutritional outcomes. Proc Biol Sci 2011; 278:2745-52. [PMID: 21288941 DOI: 10.1098/rspb.2010.2675] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Because key nutritional processes differ in their thermal optima, ectotherms may use temperature selection to optimize performance in changing nutritional environments. Such behaviour would be especially advantageous to small terrestrial animals, which have low thermal inertia and often have access to a wide range of environmental temperatures over small distances. Using the locust, Locusta migratoria, we have demonstrated a direct link between nutritional state and thermoregulatory behaviour. When faced with chronic restrictions to the supply of nutrients, locusts selected increasingly lower temperatures within a gradient, thereby maximizing nutrient use efficiency at the cost of slower growth. Over the shorter term, when locusts were unable to find a meal in the normal course of ad libitum feeding, they immediately adjusted their thermoregulatory behaviour, selecting a lower temperature at which assimilation efficiency was maximal. Thus, locusts use fine scale patterns of movement and temperature selection to adjust for reduced nutrient supply and thereby ameliorate associated life-history consequences.
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Affiliation(s)
- Nicole Coggan
- School of Biological Sciences, The University of Sydney, New South Wales 2006, Australia
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138
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Patarnello T, Verde C, di Prisco G, Bargelloni L, Zane L. How will fish that evolved at constant sub-zero temperatures cope with global warming? Notothenioids as a case study. Bioessays 2011; 33:260-8. [PMID: 21290397 DOI: 10.1002/bies.201000124] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Current climate change has raised concerns over the fate of the stenothermal Antarctic marine fauna (animals that evolved to live in narrow ranges of cold temperatures). The present paper focuses on Notothenioidei, a taxonomic group that dominates Antarctic fish. Notothenioids evolved in the Southern Ocean over the last 20 million years, providing an example of a marine species flock with unique adaptations to the cold at morphological, physiological and biochemical levels. Their phenotypic modifications are often accompanied by 'irreversible' genomic losses or gene amplifications. On a micro-evolutionary scale, relatively 'shallow' genetic variation is observed, on account of past fluctuations in population size, and a significant genetic structure is evident, suggesting low population connectivity. These features suggest that Antarctic fish might have relatively little potential to adapt to global warming, at least at a genetic level. The extent of their phenotypic plasticity, which is evident to some degree, awaits further research.
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Affiliation(s)
- Tomaso Patarnello
- Department of Public Health, Comparative Pathology and Veterinary Hygiene AGRIPOLIS, Legnaro (PD), Italy.
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139
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Stuginski DR, Fernandes W, Tattersall GJ, Abe AS. Postprandial thermogenesis in Bothrops moojeni (Serpentes: Viperidae). J Venom Anim Toxins Incl Trop Dis 2011. [DOI: 10.1590/s1678-91992011000300008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023] Open
Affiliation(s)
| | | | | | - AS Abe
- São Paulo State University, Brazil
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140
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Ontogeny and Nutritional Status Influence Oxidative Kinetics of Nutrients and Whole-Animal Bioenergetics in Zebra Finches,Taeniopygia guttata: New Applications for13C Breath Testing. Physiol Biochem Zool 2011; 84:32-42. [DOI: 10.1086/657285] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Abstract
Yawning appears to be involved in arousal, state change, and activity across vertebrates. Recent research suggests that yawning may support effective changes in mental state or vigilance through cerebral cooling. To further investigate the relationship between yawning, state change, and thermoregulation, 12 Sprague-Dawley rats (Rattus norvegicus) were exposed to a total of two hours of ambient temperature manipulation over a period of 48 hours. Using a repeated measures design, each rat experienced a range of increasing (22→32°C), decreasing (32→22°C), and constant temperatures (22°C; 32°C). Yawning and locomotor activity occurred most frequently during initial changes in temperature, irrespective of direction, compared to more extended periods of temperature manipulation. The rate of yawning also diminished during constant high temperatures (32°C) compared to low temperatures (22°C). Unlike yawning, however, stretching was unaffected by ambient temperature variation. These findings are compared to recent work on budgerigars (Melopsittacus undulatus), and the ecological selective pressures for yawning in challenging thermal environments are discussed. The results support previous comparative research connecting yawning with arousal and state change, and contribute to refining the predictions of the thermoregulatory hypothesis across vertebrates.
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Affiliation(s)
- Andrew C. Gallup
- Department of Biological Sciences, Binghamton University, Binghamton, New York 13902
| | - Ralph R. Miller
- Department of Psychology, Binghamton University, Binghamton, New York 13902
| | - Anne B. Clark
- Department of Biological Sciences, Binghamton University, Binghamton, New York 13902
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143
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F15599, a highly selective post-synaptic 5-HT(1A) receptor agonist: in-vivo profile in behavioural models of antidepressant and serotonergic activity. Int J Neuropsychopharmacol 2010; 13:1285-98. [PMID: 20059805 DOI: 10.1017/s1461145709991222] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
F15599 is a novel agonist with high selectivity and efficacy at serotonin 5-HT(1A) receptors (5-HT(1A)Rs). In signal transduction, electrophysiological and neurochemical tests, F15599 preferentially activates post-synaptic 5-HT(1A)Rs in rat frontal cortex. Such a profile may translate to an improved profile of therapeutic activity for mood disorders. The in-vivo effects of F15599 were therefore compared with those of a related compound, F13714, in rat models of antidepressant activity and 5-HT(1A)R activation: forced swimming test (FST), conditioned stress-induced ultrasonic vocalization, 5-HT syndrome, plasma corticosterone and body temperature. Acute administration of F15599 or F13714 reduced immobility in the FST at low doses; these effects were long lasting and the effects of F15599 were maintained after repeated (5 d, p.o.) administration. Both compounds decreased ultrasonic vocalization duration at low doses. In contrast, higher doses of F15599 were required to induce lower lip retraction, elements of the 5-HT behavioural syndrome, hypothermia and to increase plasma corticosterone levels. Notably, there was a greater separation of ED50 between FST and other effects for F15599 than for F13714. Thus, the in-vivo potency of F15599 in models of antidepressant/anti-stress activity is similar to that of F13714, despite the fact that the latter has an in-vitro potency two orders of magnitude greater. In contrast F15599 has a lower propensity than F13714 to induce other serotonergic signs. The distinctive pharmacological profile of F15599 suggests that preferential targeting of post-synaptic 5-HT(1A)Rs constitutes a promising strategy for improved antidepressant therapy.
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144
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Amino acid composition in endothermic vertebrates is biased in the same direction as in thermophilic prokaryotes. BMC Evol Biol 2010; 10:263. [PMID: 20807394 PMCID: PMC2939578 DOI: 10.1186/1471-2148-10-263] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2010] [Accepted: 08/31/2010] [Indexed: 11/18/2022] Open
Abstract
Background Among bacteria and archaea, amino acid usage is correlated with habitat temperatures. In particular, protein surfaces in species thriving at higher temperatures appear to be enriched in amino acids that stabilize protein structure and depleted in amino acids that decrease thermostability. Does this observation reflect a causal relationship, or could the apparent trend be caused by phylogenetic relatedness among sampled organisms living at different temperatures? And do proteins from endothermic and exothermic vertebrates show similar differences? Results We find that the observed correlations between the frequencies of individual amino acids and prokaryotic habitat temperature are strongly influenced by evolutionary relatedness between the species analysed; however, a proteome-wide bias towards increased thermostability remains after controlling for phylogeny. Do eukaryotes show similar effects of thermal adaptation? A small shift of amino acid usage in the expected direction is observed in endothermic ('warm-blooded') mammals and chicken compared to ectothermic ('cold-blooded') vertebrates with lower body temperatures; this shift is not simply explained by nucleotide usage biases. Conclusion Protein homologs operating at different temperatures have different amino acid composition, both in prokaryotes and in vertebrates. Thus, during the transition from ectothermic to endothermic life styles, the ancestors of mammals and of birds may have experienced weak genome-wide positive selection to increase the thermostability of their proteins.
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145
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Branco LGS, Bicego KC, Carnio EC, Pittman QJ. Gaseous neurotransmitters and their role in anapyrexia. Front Biosci (Elite Ed) 2010; 2:948-60. [PMID: 20515766 DOI: 10.2741/e154] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Mammals keep their body temperature (Tb) relatively constant even under a wide range of ambient temperature variation. However, in some particular situations it may be beneficial to increase or to decrease Tb. For instance, under hypoxic conditions, a regulated drop in Tb (anapyrexia) takes place which has been reported to be crucial for survival in a number of different species. This review highlights major advances in the research about nitric oxide (NO) and carbon monoxide (CO- where data are relatively less abundant), before focusing on the role played by these gaseous neuromediators in thermoregulation, under the conditions of euthermia and anapyrexia. Available data are consistent with the notion that both NO and CO, acting on the CNS, participate in thermoregulation, with NO decreasing Tb and CO increasing it. However further studies are required before definitive conclusions can be made as to their physiological mechanisms of action.
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Affiliation(s)
- Luiz G S Branco
- Dental School of Ribeirao Preto, University of Sao Paulo, Ribeirao Preto, Sao Paulo, Brazil.
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146
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Ward AJW, Hensor EMA, Webster MM, Hart PJB. Behavioural thermoregulation in two freshwater fish species. JOURNAL OF FISH BIOLOGY 2010; 76:2287-2298. [PMID: 20557593 DOI: 10.1111/j.1095-8649.2010.02576.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
In the presence of a vertical thermal gradient, juvenile three-spined sticklebacks Gasterosteus aculeatus and minnows Phoxinus phoxinus positioned themselves higher in the water column compared with adult conspecifics. This result was consistent regardless of whether age cohorts were tested separately or together. Furthermore, juveniles but not adult fishes positioned themselves higher in water column in the presence of a thermal gradient compared with those in the absence of a thermal gradient. Juvenile G. aculeatus and adult fish of both species did opt to position themselves higher in the water column in the hours immediately following a feeding event relative to their positions in the same gradient when they had not fed.
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Affiliation(s)
- A J W Ward
- School of Biological Sciences, University of Sydney, Sydney, NSW 2038, Australia.
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147
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Reduced stress fever is accompanied by increased glucocorticoids and reduced PGE2 in adult rats exposed to endotoxin as neonates. J Neuroimmunol 2010; 225:77-81. [PMID: 20546941 DOI: 10.1016/j.jneuroim.2010.04.018] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2010] [Revised: 04/26/2010] [Accepted: 04/27/2010] [Indexed: 11/22/2022]
Abstract
Immune challenges during neonatal period may permanently program immune responses later in life, including endotoxin fever. We tested the hypothesis that neonatal endotoxin exposure affects stress fever in adult rats. In control rats (treated with saline as neonates; nSal) body temperature peaked approximately 1.5 degrees C during open-field stress, whereas in rats exposed to endotoxin (lipopolysaccharide, LPS) as neonates (nLPS) stress fever was significantly attenuated. Following stress, plasma corticosterone levels significantly increased from 74.29+/-7.05 ng ml(-1) to 226.29+/-9.87 ng ml(-1) in nSal rats, and from 83.43+/-10.31 ng ml(-1) to 324.7+/-36.87 ng ml(-1) in nLPS rats. Animals treated with LPS as neonates and adrenalectomized one week before experimentation no longer displayed the attenuated febrile response to stress. This attenuated stress fever caused by an increased corticosterone secretion is likely to be linked to an inhibitory effect of glucocorticoids on cyclooxygenase activity/PGE(2) production in preoptic/anteroventral third ventricular region (AV3V) since stress failed to cause a significant increase in PGE(2) in nLPS rats, and this effect was reverted by adrenalectomy. Altogether, the present results indicate that endogenous glucocorticoids are key modulators of the attenuated stress fever in adult rats treated with LPS as neonates, and they act downregulating PGE(2) production in AV3V. Moreover, our findings also support the notion that neonatal immune stimulus affects programming of stress responses during adulthood, despite the fact that inflammation and stress are two distinct processes mediated largely by different neurobiological mechanisms.
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148
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Durocher J, Bynum J, León W, Barrera G, Winikoff B. High fever following postpartum administration of sublingual misoprostol. BJOG 2010; 117:845-52. [PMID: 20406228 PMCID: PMC2878599 DOI: 10.1111/j.1471-0528.2010.02564.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Objective To explore what triggers an elevated body temperature of ≥40.0°C in some women given misoprostol, a prostaglandin E1 analogue, for postpartum haemorrhage (PPH). Design Post hoc analysis. Setting One tertiary-level hospital in Quito, Ecuador. Population A cohort of 58 women with a fever of above 40°C following treatment with sublingual misoprostol (800 micrograms) for PPH. Methods Side effects were documented for 163 Ecuadorian women given sublingual misoprostol to treat their PPH. Women’s body temperatures were measured, and if they had a fever of ≥40.0°C, measurements were taken hourly until the fever subsided. Temperature trends were analysed, and the possible physiological mechanisms by which postpartum misoprostol produces a high fever were explored. Main outcome measures The onset, duration, peak temperatures, and treatments administered for cases with a high fever. Results Fifty-eight of 163 women (35.6%) treated with misoprostol experienced a fever of ≥40.0°C. High fevers followed a predictable pattern, often preceded by moderate/severe shivering within 20 minutes of treatment. Body temperatures peaked 1–2 hours post-treatment, and gradually declined over 3 hours. Fevers were transient and did not lead to any hospitalisation. Baseline characteristics were comparable among women who did and did not develop a high fever, except for known previous PPH and time to placental expulsion. Conclusions An unexpectedly high rate of elevated body temperature of ≥40.0°C was documented in Ecuador following sublingually administered misoprostol. It is unclear why temperatures ≥40.0°C occurred with a greater frequency in Ecuador than in other study populations using similar treatment regimens for PPH. Pharmacogenetic studies may shed further light on variations in individuals’ responses to misoprostol.
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Affiliation(s)
- J Durocher
- Gynuity Health Projects, New York, NY, USA.
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149
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Møller AP. Body temperature and fever in a free-living bird. Comp Biochem Physiol B Biochem Mol Biol 2010; 156:68-74. [PMID: 20188208 DOI: 10.1016/j.cbpb.2010.02.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2010] [Revised: 02/19/2010] [Accepted: 02/20/2010] [Indexed: 11/30/2022]
Abstract
Fever is an adaptive physiological response that animals use to fight infections by microorganisms. Although used routinely by veterinary and medical doctors for assessment of health status, there are hardly any studies of fever in free-living animals. Body temperature in a sample of more than 500 adult barn swallows Hirundo rustica varied considerably, but was consistent among capture events. Body temperature increased during the day, and reached a minimum in the middle of the breeding season. A normal quantile plot revealed that 4.5% of adults constituted a separate population that had fever. There were only marginal effects of handling on body temperature. Body temperature increased by 2.6 standard deviations following injection with LPS, showing that body temperature indeed increased with an immune challenge. Body temperature was negatively related to abundance of feather mites, but was not related to abundance of other ectoparasites or size of the uropygial gland. Barn swallows with high body temperatures also had large body mass and showed weak stress responses as reflected by their tonic immobility. Barn swallows in large colonies had lower body temperatures than solitary or less colonial individuals. Body temperature was not related to arrival date, timing of breeding, annual fecundity or adult survival. However, individuals that were easier to catch had higher body temperatures. These findings suggest that body temperature is a consistent physiological parameter of individuals, a small fraction of individuals has fever, and that febrile individuals have specific parasite loads, body mass, social environment and ability to escape capture.
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150
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Fangue NA, Podrabsky JE, Crawshaw LI, Schulte PM. Countergradient variation in temperature preference in populations of killifish Fundulus heteroclitus. Physiol Biochem Zool 2010; 82:776-86. [PMID: 19732025 DOI: 10.1086/606030] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Behavioral thermoregulation can allow ectotherms to buffer the effects of changes in environmental temperature, and thus an organism's preferred temperature is thought to be under strong selection. However, this contention has seldom been tested. We used common killifish Fundulus heteroclitus from high-latitude (northern) and low-latitude (southern) populations to investigate intraspecific variation in thermal preference and its relationship to habitat temperature. We quantified the preferred temperatures of northern and southern killifish populations acclimated to three temperatures (5 degrees , 15 degrees , and 25 degrees C) to evaluate two alternative hypotheses for the evolution of differences in thermal preference among latitudinally separated populations: local thermal adaptation, which predicts that organisms from high latitudes should prefer lower temperatures than individuals from lower latitudes, versus countergradient variation, which predicts that high-latitude organisms should prefer higher temperatures to compensate for shorter growing seasons. All killifish selected their final thermal preferendum within 4 h. Southern killifish and killifish acclimated to warmer temperatures had greater variability in selected temperature. This increase in variability was the result of an increase in interindividual variation in preferred temperature rather than a reduction in the precision of temperature selection in these groups. Northern killifish preferred significantly higher temperatures than southern fish (30.6 degrees vs. 29.0 degrees C, respectively, when calculated on the basis of the temperature selected consistently for at least 30 min; 28.4 degrees vs. 26.5 degrees C, respectively, when calculated on the basis of the mean temperature occupied), regardless of acclimation temperature. These data are not consistent with local adaptation in thermal preference but instead can be better explained by countergradient variation in thermal preference in killifish.
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Affiliation(s)
- Nann A Fangue
- Department of Zoology, University of British Columbia, 6270 University Boulevard, Vancouver, British Columbia V6T 1Z4, Canada.
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