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Islam MA, Lomax S, Doughty AK, Islam MR, Thomson PC, Clark CEF. Revealing the diversity of internal body temperature and panting response for feedlot cattle under environmental thermal stress. Sci Rep 2023; 13:4879. [PMID: 36966196 PMCID: PMC10039931 DOI: 10.1038/s41598-023-31801-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Accepted: 03/17/2023] [Indexed: 03/27/2023] Open
Abstract
Core body temperature (CBT) regulation is crucial for mammalian wellbeing and survival. Cattle pant to dissipate excess heat to regulate CBT when ambient conditions exceed thermoneutral zones. However, to date, neither the variability in cattle heat response, the lagged response of CBT to thermal indices, nor the diurnal patterns of thermal indices, CBT and panting have been reported in the literature. We decomposed thermal indices, CBT and panting time-series data for 99 feedlot heifers across three discrete heat events into diurnal, trend and residual components. Both raw and decomposed data were analysed to explore the lagged CBT and panting responses and the association between series. We show ambient thermal conditions impact CBT with a 1-h lag despite a lag of between 1.5 to 3 h from raw data. Average individual panting scores were used to identify heat-susceptible and heat-tolerant cattle. Heat-susceptible cattle showed greater CBT (P < 0.01) between 8:00 and 23:00 and greater panting duration (P < 0.05) between 10:00 and 18:00 than heat-tolerant cattle under the same thermal conditions and these variations followed a similar pattern despite differences in cattle breed. This new information enables targeted amelioration and selection of individuals against heat susceptibility.
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Affiliation(s)
- M A Islam
- Livestock Production and Welfare Group, School of Life and Environmental Sciences, Sydney Institute of Agriculture, University of Sydney, Camden, New South Wales, 2570, Australia.
- Department of Dairy Science, Faculty of Animal Science and Veterinary Medicine, Patuakhali Science and Technology University, Dumki, Patuakhali, 8602, Bangladesh.
| | - S Lomax
- Livestock Production and Welfare Group, School of Life and Environmental Sciences, Sydney Institute of Agriculture, University of Sydney, Camden, New South Wales, 2570, Australia
| | - A K Doughty
- Allflex Livestock Intelligence, Allflex Australia Pty Ltd., 33 Neumann Road, Capalaba, Queensland, 4157, Australia
| | - M R Islam
- Livestock Production and Welfare Group, School of Life and Environmental Sciences, Sydney Institute of Agriculture, University of Sydney, Camden, New South Wales, 2570, Australia
| | - P C Thomson
- Sydney School of Veterinary Science, University of Sydney, Camden, New South Wales, 2570, Australia
| | - C E F Clark
- Livestock Production and Welfare Group, School of Life and Environmental Sciences, Sydney Institute of Agriculture, University of Sydney, Camden, New South Wales, 2570, Australia
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Haman F, Souza SCS, Castellani JW, Dupuis MP, Friedl KE, Sullivan-Kwantes W, Kingma BRM. Human vulnerability and variability in the cold: Establishing individual risks for cold weather injuries. Temperature (Austin) 2022; 9:158-195. [DOI: 10.1080/23328940.2022.2044740] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Affiliation(s)
- François Haman
- Faculty of Health Sciences, University of Ottawa, Ottawa,Ontario, Canada
| | - Sara C. S. Souza
- Faculty of Health Sciences, University of Ottawa, Ottawa,Ontario, Canada
| | - John W. Castellani
- Thermal and Mountain Medicine Division, US Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA
| | - Maria-P. Dupuis
- Faculty of Health Sciences, University of Ottawa, Ottawa,Ontario, Canada
| | - Karl E. Friedl
- Thermal and Mountain Medicine Division, US Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA
| | - Wendy Sullivan-Kwantes
- Biophysics and Biomedical Modeling Division, Defence Research Development Canada-Toronto, Defence Research and Development Canada, Ontario, Canada
| | - Boris R. M. Kingma
- Netherlands Organization for Applied Scientific Research, Department of Human Performance, Unit Defence, Safety and Security, Soesterberg, The Netherlands
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Islam MA, Lomax S, Doughty A, Islam MR, Jay O, Thomson P, Clark C. Automated Monitoring of Cattle Heat Stress and Its Mitigation. FRONTIERS IN ANIMAL SCIENCE 2021. [DOI: 10.3389/fanim.2021.737213] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Climate change related global warming is likely to continue, despite all mitigation measures taken by humans, due to the lag effect of long-term anthropogenic activities. Warming of the atmosphere can impact worldwide cattle production directly by compromising health, welfare and productivity, and indirectly by reducing the quality and quantity of animal feed. Under warm thermal conditions, cattle adjust their physiological and behavioural responses as an integral part of thermoregulation to maintain internal body temperature within a safe range. However, a greater intensity and duration of heat exposure can exceed thermoregulatory capacity leading to an increase in internal body temperature beyond the normal limit that ultimately evokes different animal responses to heat. In cattle, response to heat stress can be visually observed as elevated respiration rate or panting, but continuous visual monitoring is labour intensive, time consuming and subjective. Therefore, different weather-based indices have been developed such as the temperature humidity index (THI) and heat load index (HLI) which are commonly used weather-based indices for monitoring cattle heat stress at commercial level. However, the thermal comfort level of cattle based on weather-based indices has limited use at a microclimatic and individual animal level. Varying sensor-based approaches have shown promise to shift the focus of heat stress management to the individual level. Monitoring individual animal response and mitigation strategies for isolated heat-susceptible cattle could save on heat management costs whilst improving animal welfare and productivity. Here we review the technologies that enable automatic, continuous, and real-time cattle heat stress monitoring and mitigation under commercial conditions. Future platforms for autonomous monitoring and mitigation of heat stress in cattle are likely to be based on minimally-invasive smart technologies either singly, or in an integrated system, enabling real-time solutions to animal responses under various production systems and environmental conditions.
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Hale BJ, Li Y, Adur MK, Keating AF, Baumgard LH, Ross JW. Characterization of the effects of heat stress on autophagy induction in the pig oocyte. Reprod Biol Endocrinol 2021; 19:107. [PMID: 34243771 PMCID: PMC8268447 DOI: 10.1186/s12958-021-00791-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 06/23/2021] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Heat stress (HS) occurs when body heat accumulation exceeds heat dissipation and is associated with swine seasonal infertility. HS contributes to compromised oocyte integrity and reduced embryo development. Autophagy is a potential mechanism for the oocyte to mitigate the detrimental effects of HS by recycling damaged cellular components. METHODS To characterize the effect of HS on autophagy in oocyte maturation, we utilized an in vitro maturation (IVM) system where oocytes underwent thermal neutral (TN) conditions throughout the entire maturation period (TN/TN), HS conditions during the first half of IVM (HS/TN), or HS conditions during the second half of IVM (TN/HS). RESULTS To determine the effect of HS on autophagy induction within the oocyte, we compared the relative abundance and localization of autophagy-related proteins. Heat stress treatment affected the abundance of two well described markers of autophagy induction: autophagy related gene 12 (ATG12) in complex with ATG5 and the cleaved form of microtubule-associated protein 1 light chain 3 beta (LC3B-II). The HS/TN IVM treatment increased the abundance of the ATG12-ATG5 complex and exacerbated the loss of LC3B-II in oocytes. The B-cell lymphoma 2 like 1 protein (BCL2L1) can inhibit autophagy or apoptosis through its interaction with either beclin1 (BECN1) or BCL2 associated X, apoptosis regulator (BAX), respectively. We detected colocalization of BCL2L1 with BAX but not BCL2L1 with BECN1, suggesting that apoptosis is inhibited under the HS/TN treatment but not autophagy. Interestingly, low doses of the autophagy inducer, rapamycin, increased oocyte maturation. CONCLUSIONS Our results here suggest that HS increases autophagy induction in the oocyte during IVM, and that artificial induction of autophagy increases the maturation rate of oocytes during IVM. These data support autophagy as a potential mechanism activated in the oocyte during HS to recycle damaged cellular components and maintain developmental competence.
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Affiliation(s)
- Benjamin J Hale
- Department of Animal Science, Iowa State University, 2356 Kildee Hall, Ames, IA, 50011, USA
| | - Yunsheng Li
- Department of Animal Science, Iowa State University, 2356 Kildee Hall, Ames, IA, 50011, USA
| | - Malavika K Adur
- Department of Animal Science, Iowa State University, 2356 Kildee Hall, Ames, IA, 50011, USA
| | - Aileen F Keating
- Department of Animal Science, Iowa State University, 2356 Kildee Hall, Ames, IA, 50011, USA
| | - Lance H Baumgard
- Department of Animal Science, Iowa State University, 2356 Kildee Hall, Ames, IA, 50011, USA
| | - Jason W Ross
- Department of Animal Science, Iowa State University, 2356 Kildee Hall, Ames, IA, 50011, USA.
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Ciuha U, Tobita K, McDonnell AC, Mekjavic IB. The effect of thermal transience on the perception of thermal comfort. Physiol Behav 2019; 210:112623. [PMID: 31325511 DOI: 10.1016/j.physbeh.2019.112623] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Revised: 06/18/2019] [Accepted: 07/16/2019] [Indexed: 11/26/2022]
Abstract
INTRODUCTION The present study tested the hypothesis that at any given ambient temperature (Ta), thermal comfort (TC) is not only a function of the temperature per se, but is also influenced by the temperatures rate of change and direction. METHODS Twelve healthy young (age: 23 ± 3) male participants completed experimental trials where Ta increased from 15° to 40 °C (heating) and then decreased from 40 to 15 °C (cooling). In one trial (FAST), the rate of change in Ta was maintained at 1 °C.min-1, and in the other (SLOW) at 0.5 °C.min-1. During each trial participants provided ratings of TC at 3-min intervals to determine their thermal comfort zone (TCZ). RESULTS In the FAST trial, participants identified TCZ at an Ta between 22 ± 4 and 30 ± 4 °C during heating and between 25 ± 3 and 33 ± 3 °C during cooling phase (p = .003), and in the SLOW trial between 21 ± 3 and 33 ± 4 °C during heating and between 23 ± 4 and 34 ± 3 °C during cooling phase (p = .012). During the heating phase TCZ was established at a lower range of Ta, compared to cooling phase. The difference between the heating and cooling phases in preferred range of Ta was more pronounced in the FAST compared to SLOW trial. CONCLUSION TCZ is influenced not only by the prevailing temperature, but also by the direction and the rate of the change in Ta. Faster changes in Ta (1 °C.min-1) established the TCZ at a higher Ta during cooling and at a lower Ta during heating phase.
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Affiliation(s)
- Urša Ciuha
- Department of Automation, Biocybernetics and Robotics, Jozef Stefan Institute, Jamova 39, SI-1000 Ljubljana, Slovenia.
| | - Kunihito Tobita
- Department of Automation, Biocybernetics and Robotics, Jozef Stefan Institute, Jamova 39, SI-1000 Ljubljana, Slovenia; Department of Sustainable System Sciences, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka 599-8531, Japan
| | - Adam C McDonnell
- Department of Automation, Biocybernetics and Robotics, Jozef Stefan Institute, Jamova 39, SI-1000 Ljubljana, Slovenia
| | - Igor B Mekjavic
- Department of Automation, Biocybernetics and Robotics, Jozef Stefan Institute, Jamova 39, SI-1000 Ljubljana, Slovenia; Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
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The origin, significance and plasticity of the thermoeffector thresholds: Extrapolation between humans and laboratory rodents. J Therm Biol 2019; 85:102397. [DOI: 10.1016/j.jtherbio.2019.08.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2019] [Revised: 08/05/2019] [Accepted: 08/05/2019] [Indexed: 01/07/2023]
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Taylor NA, Nykvist Å, Powers N, Caldwell JN. Thermoeffector threshold plasticity: The impact of thermal pre-conditioning on sudomotor, cutaneous vasomotor and thermogenic thresholds. J Therm Biol 2019; 83:37-46. [DOI: 10.1016/j.jtherbio.2019.05.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Accepted: 05/02/2019] [Indexed: 12/16/2022]
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8
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Botonis PG, Miliotis PG, Kounalakis SN, Koskolou MD, Geladas ND. Effects of capsaicin application on the skin during resting exposure to temperate and warm conditions. Scand J Med Sci Sports 2018; 29:171-179. [PMID: 30294815 DOI: 10.1111/sms.13317] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Revised: 09/20/2018] [Accepted: 10/01/2018] [Indexed: 11/28/2022]
Abstract
We investigated thermoregulatory and cardiovascular responses at rest in a temperate (20°C) and in a warm (30°C) environment (40% RH) without and with the application of capsaicin on the skin. We hypothesized that regardless of environmental temperature, capsaicin application would stimulate heat loss and concomitantly deactivate heat conservation mechanisms, thus resulting in rectal temperature (Tre) and mean blood pressure decline due to excitation of heat-sensitive TRPV1. Ten male subjects were exposed, while seated, for 30 minutes to 20.8 ± 1.0°C or to 30.6 ± 1.1°C: without (NCA) and with (CA) application of capsaicin patches on the skin. Thermoregulatory (Tre, proximal-distal skin temperature gradient) and cardiovascular variables (modelflow technique) as well as oxygen uptake were continuously measured. The area under the curve for Tre decline at 20°C was smaller in CA (-2.1 ± 1.3 a.u.) than in NCA (-0.6 ± 1.1 a.u., P < 0.01, r = 0.8). Likewise, at 30°C it was smaller in CA (-2.2 ± 2.1 a.u.) compared to NCA (-0.8 ± 2.0 a.u., P = 0.02, r = 0.7). Local vasomotor tone and oxygen uptake, were significantly lower by 36.7% ± 94.2% and 12.3% ± 12.3%, respectively, with capsaicin compared to NCA (P = 0.05 and P < 0.01, respectively). Additionally, in 30°C CA mean arterial pressure was lower by 10.7% ± 5.9%, 8.9% ± 5.9%, and 10.6% ± 7.0% compared to 30°C NCA, 20°C NCA, and 20°C CA, respectively (P < 0.01, P = 0.02, and P < 0.01, respectively, d = 1.4-1.8). In conclusion, capsaicin application on the skin induced vasodilation and Tre decline. At 30°C CA, thermal responses were accompanied by arterial hypotension most likely due to the interactive effects of both stressors (warm environment and capsaicin) on cutaneous vascular regulation.
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Affiliation(s)
- Petros G Botonis
- Section of Sport Medicine and Biology of Exercise, School of Physical Education and Sport Science, National and Kapodistrian University of Athens, Athens, Greece
| | - Panagiotis G Miliotis
- Section of Sport Medicine and Biology of Exercise, School of Physical Education and Sport Science, National and Kapodistrian University of Athens, Athens, Greece
| | - Stylianos N Kounalakis
- Faculty of Physical and Cultural Education, Evelpidon Hellenic Army Academy, Vari, Greece
| | - Maria D Koskolou
- Section of Sport Medicine and Biology of Exercise, School of Physical Education and Sport Science, National and Kapodistrian University of Athens, Athens, Greece
| | - Nickos D Geladas
- Section of Sport Medicine and Biology of Exercise, School of Physical Education and Sport Science, National and Kapodistrian University of Athens, Athens, Greece
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Abstract
Heat exchange processes between the body and the environment are introduced. The definition of the thermoneutral zone as the ambient temperature range within which body temperature (Tb) regulation is achieved only by nonevaporative processes is explained. Thermoreceptors, thermoregulatory effectors (both physiologic and behavioral), and neural pathways and Tb signals that connect receptors and effectors into a thermoregulation system are reviewed. A classification of thermoeffectors is proposed. A consensus concept is presented, according to which the thermoregulation system is organized as a dynamic federation of independent thermoeffector loops. While the activity of each effector is driven by a unique combination of deep (core) and superficial (shell) Tbs, the regulated variable of the system can be viewed as a spatially distributed Tb with a heavily represented core and a lightly represented shell. Core Tb is the main feedback; it is always negative. Shell Tbs (mostly of the hairy skin) represent the auxiliary feedback, which can be negative or positive, and which decreases the system's response time and load error. Signals from the glabrous (nonhairy) skin about the temperature of objects in the environment serve as feedforward signals for various behaviors. Physiologic effectors do not use feedforward signals. The system interacts with other homeostatic systems by "meshing" with their loops. Coordination between different thermoeffectors is achieved through the common controlled variable, Tb. The term balance point (not set point) is used for a regulated level of Tb. The term interthreshold zone is used for a Tb range in which no effectors are activated. Thermoregulatory states are classified, based on whether: Tb is increased (hyperthermia) or decreased (hypothermia); the interthreshold zone is narrow (homeothermic type of regulation) or wide (poikilothermic type); and the balance point is increased (fever) or decreased (anapyrexia). During fever, thermoregulation can be either homeothermic or poikilothermic; anapyrexia is always a poikilothermic state. The biologic significance of poikilothermic states is discussed. As an example of practical applications of the concept presented, thermopharmacology is reviewed. Thermopharmacology uses drugs to modulate specific temperature signals at the level of a thermoreceptor (transient receptor potential channel).
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Szolcsányi J. Effect of capsaicin on thermoregulation: an update with new aspects. Temperature (Austin) 2015; 2:277-96. [PMID: 27227029 PMCID: PMC4843897 DOI: 10.1080/23328940.2015.1048928] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Revised: 05/04/2015] [Accepted: 05/04/2015] [Indexed: 01/07/2023] Open
Abstract
Capsaicin, a selective activator of the chemo- and heat-sensitive transient receptor potential (TRP) V1 cation channel, has characteristic feature of causing long-term functional and structural impairment of neural elements supplied by TRPV1/capsaicin receptor. In mammals, systemic application of capsaicin induces complex heat-loss response characteristic for each species and avoidance of warm environment. Capsaicin activates cutaneous warm receptors and polymodal nociceptors but has no effect on cold receptors or mechanoreceptors. In this review, thermoregulatory features of capsaicin-pretreated rodents and TRPV1-mediated neural elements with innocuous heat sensitivity are summarized. Recent data support a novel hypothesis for the role of visceral warmth sensors in monitoring core body temperature. Furthermore, strong evidence suggests that central presynaptic nerve terminals of TRPV1-expressing cutaneous, thoracic and abdominal visceral receptors are activated by innocuous warmth stimuli and capsaicin. These responses are absent in TRPV1 knockout mice. Thermoregulatory disturbance induced by systemic capsaicin pretreatment lasts for months and is characterized by a normal body temperature at cool environment up to a total dose of 150 mg/kg s.c. Upward differential shift of set points for activation vasodilation, other heat-loss effectors and thermopreference develops. Avoidance of warm ambient temperature (35°C, 40°C) is severely impaired but thermopreference at cool ambient temperatures (Tas) are not altered. TRPV1 knockout or knockdown and genetically altered TRPV1, TRPV2 and TRPM8 knockout mice have normal core temperature in thermoneutral or cool environments, but the combined mutant mice have impaired regulation in warm or cold (4°C) environments. Several lines of evidence support that in the preoptic area warmth sensitive neurons are activated and desensitized by capsaicin, but morphological evidence for it is controversial. It is suggested that these neurons have also integrator function. Fever is enhanced in capsaicin-desensitized rats and the inhibition observed after pretreatment with low i.p. doses does not support in the light of their warmth sensitivity the concept that abdominal TRPV1-expressing nerve terminals serve as nonthermal chemosensors for reference signals in thermoregulation.
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Key Words
- (s)EPSC(s), (spontaneous) excitatory postsynaptic current(s)
- DRG, dorsal root ganglion (ganglia)
- EGFP, enhanced green fluorescent protein
- LC, locus coeruleus
- LPS, lipopolysaccharide
- NTS, nucleus of the solitary tract
- PG(s), prostaglandin(s)
- POA, the preoptic area (of the hypothalamus)
- RTX, resiniferatoxin
- TRP, transient receptor potential
- TRPM8
- TRPV1
- Ta(s), ambient temperature(s)
- Tr, rectal temperature
- Ts, skin temperature
- Tt, tail temperature
- capsaicin
- fever
- preoptic area
- thermoregulation
- visceral thermoreceptors
- warm receptors
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Affiliation(s)
- János Szolcsányi
- Department of Pharmacology and Pharmacotherapy; University Medical School of Pécs; Pécs, Hungary; Szentágothai Research Centre University of Pécs; Pécs, Hungary
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If there is a “time to target temperature paradox” in post-cardiac arrest care, would we know? Resuscitation 2015; 88:A3-4. [DOI: 10.1016/j.resuscitation.2014.12.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2014] [Accepted: 12/15/2014] [Indexed: 10/24/2022]
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Abstract
Modeling for cold stress has generated a rich history of innovation, has exerted a catalytic influence on cold physiology research, and continues to impact human activity in cold environments. This overview begins with a brief summation of cold thermoregulatory model development followed by key principles that will continue to guide current and future model development. Different representations of the human body are discussed relative to the level of detail and prediction accuracy required. In addition to predictions of shivering and vasomotor responses to cold exposure, algorithms are presented for thermoregulatory mechanisms. Various avenues of heat exchange between the human body and a cold environment are reviewed. Applications of cold thermoregulatory modeling range from investigative interpretation of physiological observations to forecasting skin freezing times and hypothermia survival times. While these advances have been remarkable, the future of cold stress modeling is still faced with significant challenges that are summarized at the end of this overview.
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Affiliation(s)
- Xiaojiang Xu
- Biophysics and Biomedical Modeling Division, U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts
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13
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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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14
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Abstract
Homeostasis, the dominant explanatory framework for physiological regulation, has undergone significant revision in recent years, with contemporary models differing significantly from the original formulation. Allostasis, an alternative view of physiological regulation, goes beyond its homeostatic roots, offering novel insights relevant to our understanding and treatment of several chronic health conditions. Despite growing enthusiasm for allostasis, the concept remains diffuse, due in part to ambiguity as to how the term is understood and used, impeding meaningful translational and clinical research on allostasis. Here, we provide a more focused understanding of homeostasis and allostasis by explaining how both play a role in physiological regulation, and a critical analysis of regulation suggests how homeostasis and allostasis can be distinguished. Rather than focusing on changes in the value of a regulated variable (e.g., body temperature, body adiposity, or reward), research investigating the activity and relationship among the multiple regulatory loops that influence the value of these regulated variables may be the key to distinguishing homeostasis and allostasis. The mechanisms underlying physiological regulation and dysregulation are likely to have important implications for health and disease.
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Affiliation(s)
- Douglas S. Ramsay
- Department of Oral Health Sciences, University of Washington, Seattle, Washington, USA
- Department of Orthodontics, University of Washington, Seattle, Washington, USA
- Department of Pediatric Dentistry, University of Washington, Seattle, Washington, USA
| | - Stephen C. Woods
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati Medical Center, Cincinnati, Ohio, USA
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Kingma BRM, Vosselman MJ, Frijns AJH, van Steenhoven AA, van Marken Lichtenbelt WD. Incorporating neurophysiological concepts in mathematical thermoregulation models. INTERNATIONAL JOURNAL OF BIOMETEOROLOGY 2014; 58:87-99. [PMID: 23354424 DOI: 10.1007/s00484-012-0628-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2011] [Revised: 10/14/2012] [Accepted: 12/23/2012] [Indexed: 06/01/2023]
Abstract
Skin blood flow (SBF) is a key player in human thermoregulation during mild thermal challenges. Various numerical models of SBF regulation exist. However, none explicitly incorporates the neurophysiology of thermal reception. This study tested a new SBF model that is in line with experimental data on thermal reception and the neurophysiological pathways involved in thermoregulatory SBF control. Additionally, a numerical thermoregulation model was used as a platform to test the function of the neurophysiological SBF model for skin temperature simulation. The prediction-error of the SBF-model was quantified by root-mean-squared-residual (RMSR) between simulations and experimental measurement data. Measurement data consisted of SBF (abdomen, forearm, hand), core and skin temperature recordings of young males during three transient thermal challenges (1 development and 2 validation). Additionally, ThermoSEM, a thermoregulation model, was used to simulate body temperatures using the new neurophysiological SBF-model. The RMSR between simulated and measured mean skin temperature was used to validate the model. The neurophysiological model predicted SBF with an accuracy of RMSR < 0.27. Tskin simulation results were within 0.37 °C of the measured mean skin temperature. This study shows that (1) thermal reception and neurophysiological pathways involved in thermoregulatory SBF control can be captured in a mathematical model, and (2) human thermoregulation models can be equipped with SBF control functions that are based on neurophysiology without loss of performance. The neurophysiological approach in modelling thermoregulation is favourable over engineering approaches because it is more in line with the underlying physiology.
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Affiliation(s)
- Boris R M Kingma
- Department of Human Biology, NUTRIM School for Nutrition, Toxicology and Metabolism of Maastricht University Medical Centre, Universiteitssingel 50, PO Box 616, 6200 MD, Maastricht, The Netherlands,
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Brain temperature: physiology and pathophysiology after brain injury. Anesthesiol Res Pract 2012; 2012:989487. [PMID: 23326261 PMCID: PMC3541556 DOI: 10.1155/2012/989487] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Revised: 11/09/2012] [Accepted: 12/12/2012] [Indexed: 12/02/2022] Open
Abstract
The regulation of brain temperature is largely dependent on the metabolic activity of brain tissue and remains complex. In intensive care clinical practice, the continuous monitoring of core temperature in patients with brain injury is currently highly recommended. After major brain injury, brain temperature is often higher than and can vary independently of systemic temperature. It has been shown that in cases of brain injury, the brain is extremely sensitive and vulnerable to small variations in temperature. The prevention of fever has been proposed as a therapeutic tool to limit neuronal injury. However, temperature control after traumatic brain injury, subarachnoid hemorrhage, or stroke can be challenging. Furthermore, fever may also have beneficial effects, especially in cases involving infections. While therapeutic hypothermia has shown beneficial effects in animal models, its use is still debated in clinical practice. This paper aims to describe the physiology and pathophysiology of changes in brain temperature after brain injury and to study the effects of controlling brain temperature after such injury.
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Kaiyala KJ, Chan B, Ramsay DS. Robust thermoregulatory overcompensation, rather than tolerance, develops with serial administrations of 70% nitrous oxide to rats. J Therm Biol 2012; 37:30-40. [PMID: 22247586 DOI: 10.1016/j.jtherbio.2011.10.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Changes in typical whole-animal dependent variables following drug administration represent an integral of the drug's pharmacological effect, the individual's autonomic and behavioral responses to the resulting disturbance, and many other influences. An archetypical example is core temperature (T(c)), long used for quantifying initial drug sensitivity and tolerance acquisition over repeated drug administrations. Our previous work suggested that rats differing in initial sensitivity to nitrous oxide (N(2)O)-induced hypothermia would exhibit different patterns of tolerance development across N(2)O administrations. Specifically, we hypothesized that rats with an initially insensitive phenotype would subsequently develop regulatory overcompensation that would mediate an allostatic hyperthermic state, whereas rats with an initially sensitive phenotype would subsequently compensate to a homeostatic normothermic state. To preclude confounding due to handling and invasive procedures, a valid test of this prediction required non-invasive thermal measurements via implanted telemetric temperature sensors, combined direct and indirect calorimetry, and automated drug delivery to enable repeatable steady-state dosing. We screened 237 adult rats for initial sensitivity to 70% N(2)O-induced hypothermia. Thirty highly sensitive rats that exhibited marked hypothermia when screened and 30 highly insensitive rats that initially exhibited minimal hypothermia were randomized to three groups (n=10 each/group) that received: 1) twelve 90-min exposures to 70% N(2)O using a classical conditioning procedure, 2) twelve 90-min exposures to 70% N(2)O using a random control procedure for conditioning, or 3) a no-drug control group that received custom-made air. Metabolic heat production (via indirect calorimetry), body heat loss (via direct calorimetry) and T(c) (via telemetry) were simultaneously quantified during N(2)O and control gas administrations. Initially insensitive rats rapidly acquired (3(rd) administration) a significant allostatic hyperthermic phenotype during N(2)O administration whereas initially sensitive rats exhibited classical tolerance (normothermia) during N(2)O inhalation in the 4(th) and 5(th) sessions. However, the sensitive rats subsequently acquired the hyperthermic phenotype and became indistinguishable from initially insensitive rats during the 11(th) and 12th N(2)O administrations. The major mechanism for hyperthermia was a brisk increase in metabolic heat production. However, we obtained no evidence for classical conditioning of thermal responses. We conclude that the degree of initial sensitivity to N(2)O-induced hypothermia predicts the temporal pattern of thermal adaptation over repeated N(2)O administrations, but that initially insensitive and sensitive animals eventually converge to similar (and substantial) magnitudes of within-administration hyperthermia mediated by hyper-compensatory heat production.
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Affiliation(s)
- Karl J Kaiyala
- Department of Dental Public Health Sciences, University of Washington, Seattle, WA, USA
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Cheung SS. Interconnections between thermal perception and exercise capacity in the heat. Scand J Med Sci Sports 2010; 20 Suppl 3:53-9. [DOI: 10.1111/j.1600-0838.2010.01209.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Tribukait A, Nobel G, Mekjavic IB, Eiken O. Effects of anti-histaminic and anti-cholinergic substances on human thermoregulation during cold provocation. Brain Res Bull 2010; 81:100-6. [PMID: 19576271 DOI: 10.1016/j.brainresbull.2009.06.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2009] [Accepted: 06/18/2009] [Indexed: 11/26/2022]
Abstract
The roles of histaminergic and cholinergic neuron systems in the regulation of body temperature have been studied almost exclusively in animals. Recently, we have found that motion sickness, i.e. a condition where hippocampal cholinergic mismatch signals induce a release of histamine in the vomiting centre, accelerates the decline in body temperature in men during exposure to cold. In the present study we measured the thermoregulatory effects of two substances commonly used against motion sickness, i.e. the histamine (H1) receptor blocker dimenhydrinate (DMH) and the muscarine receptor blocker scopolamine (SCOP). In three trials, control (CN), DMH and SCOP, 10 male subjects were immersed in 15 degrees C water for a maximum of 90 min. The trials were separated by a minimum of three days and their order was alternated between subjects. In all trials the subject received, in a double blind fashion, a transdermal patch (SCOP or placebo) 12-14 h before immersion and a tablet (DMH or placebo) 1h before immersion. Mean skin temperature, rectal temperature (T(rec)), the difference in temperature between the non-immersed right forearm and 3rd finger of the right hand (T(ff)), and oxygen uptake (VO(2)) were recorded. The fall in T(rec) was smaller in the DMH than in the CN and SCOP conditions. The recordings of T(ff) and VO(2) suggest that SCOP attenuates peripheral vasoconstriction while DMH increases shivering thermogenesis. Notably, thermal discomfort was reduced in the SCOP condition. Findings are thoroughly discussed in the context of animal studies on the neuropharmacology and neurophysiology of thermoregulation and motion sickness.
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Affiliation(s)
- A Tribukait
- Royal Institute of Technology, School for Technology and Health, Berzelius v. 13, Karolinska Institute, SE 171 77 Stockholm, Sweden.
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Kounalakis SN, Botonis PG, Koskolou MD, Geladas ND. The effect of menthol application to the skin on sweating rate response during exercise in swimmers and controls. Eur J Appl Physiol 2010; 109:183-9. [DOI: 10.1007/s00421-009-1345-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/21/2009] [Indexed: 10/20/2022]
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System properties, feedback control and effector coordination of human temperature regulation. Eur J Appl Physiol 2009; 109:13-25. [PMID: 19787369 DOI: 10.1007/s00421-009-1216-1] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/16/2009] [Indexed: 10/20/2022]
Abstract
The aim of human temperature regulation is to protect body processes by establishing a relative constancy of deep body temperature (regulated variable), in spite of external and internal influences on it. This is basically achieved by a distributed multi-sensor, multi-processor, multi-effector proportional feedback control system. The paper explains why proportional control implies inherent deviations of the regulated variable from the value in the thermoneutral zone. The concept of feedback of the thermal state of the body, conveniently represented by a high-weighted core temperature (T (c)) and low-weighted peripheral temperatures (T (s)) is equivalent to the control concept of "auxiliary feedback control", using a main (regulated) variable (T (c)), supported by an auxiliary variable (T (s)). This concept implies neither regulation of T (s) nor feedforward control. Steady-states result in the closed control-loop, when the open-loop properties of the (heat transfer) process are compatible with those of the thermoregulatory processors. They are called operating points or balance points and are achieved due to the inherent property of dynamical stability of the thermoregulatory feedback loop. No set-point and no comparison of signals (e.g. actual-set value) are necessary. Metabolic heat production and sweat production, though receiving the same information about the thermal state of the body, are independent effectors with different thresholds and gains. Coordination between one of these effectors and the vasomotor effector is achieved by the fact that changes in the (heat transfer) process evoked by vasomotor control are taken into account by the metabolic/sweat processor.
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Woods SC, Ramsay DS. Homeostasis: beyond Curt Richter. Appetite 2007; 49:388-98. [PMID: 17524521 PMCID: PMC2696031 DOI: 10.1016/j.appet.2006.09.015] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2006] [Revised: 08/24/2006] [Accepted: 09/07/2006] [Indexed: 12/25/2022]
Abstract
Curt Richter introduced behavioral control into the concept of homeostasis, thereby opening entire fields of research. The prevailing dogma, and the techniques he used, conspired to lead Richter and others to interpret regulation in strict negative feedback terms. Although this point of view continues to be embraced by many contemporary biologists, we believe that prevailing sentiment favors a broader view in which organisms integrate anticipatory pre-emptive control over regulated variables whenever possible.
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Affiliation(s)
- Stephen C Woods
- Department of Psychiatry, University of Cincinnati, Cincinnati, OH, USA.
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Kräuchi K. The thermophysiological cascade leading to sleep initiation in relation to phase of entrainment. Sleep Med Rev 2007; 11:439-51. [PMID: 17764994 DOI: 10.1016/j.smrv.2007.07.001] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
This article reviews circadian thermoregulation in relation to sleep induction and phase of entrainment in the light of the comprehensive thermophysiological and chronobiological concepts of Jürgen Aschoff. The idea that temperature and sleep are interrelated is based on evolutionary history. Mammalian sleep developed in association with endothermy, and all species, independent of temporal niche, usually sleep during the circadian trough of their core body temperature (CBT) rhythm. The circadian pattern of CBT results from the balance between heat production and heat loss, the latter being relevant for sleep induction. Sleep under entrained conditions is typically initiated on the declining portion of the CBT curve when its rate of change and body heat loss is maximal. Body heat loss before lights off, via selective vasodilatation of distal skin regions, promotes sleepiness and the rapid onset of sleep. This thermophysiological effect represents the cement between the circadian clock and the sleep-wake cycle, and in turn determines phase of entrainment (Psi) and sleep onset latency (SOL). These interrelationships have been recently studied in a particular subset of the general population, mainly women, who suffer from cold hands and feet (the so-called vasospastic syndrome, VS). Women with VS exhibit not only a lower capacity to lose heat during the daytime but also a prolonged SOL, a disturbed Psi of the circadian clock with respect to the sleep-wake cycle and psychologically, a disposition to turn experienced anger inwards. This naturalistic model leads us to a more general conclusion that regulation of distal skin blood flow may have clinical relevance for insomnia, in particular sleep onset insomnia.
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Affiliation(s)
- Kurt Kräuchi
- Centre for Chronobiolgy, Psychiatric University Clinics, Wilhelm Klein Strasse 27, 4025 Basel, Switzerland.
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Romanovsky AA. Thermoregulation: some concepts have changed. Functional architecture of the thermoregulatory system. Am J Physiol Regul Integr Comp Physiol 2007; 292:R37-46. [PMID: 17008453 DOI: 10.1152/ajpregu.00668.2006] [Citation(s) in RCA: 415] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
While summarizing the current understanding of how body temperature (Tb) is regulated, this review discusses the recent progress in the following areas: central and peripheral thermosensitivity and temperature-activated transient receptor potential (TRP) channels; afferent neuronal pathways from peripheral thermosensors; and efferent thermoeffector pathways. It is proposed that activation of temperature-sensitive TRP channels is a mechanism of peripheral thermosensitivity. Special attention is paid to the functional architecture of the thermoregulatory system. The notion that deep Tb is regulated by a unified system with a single controller is rejected. It is proposed that Tb is regulated by independent thermoeffector loops, each having its own afferent and efferent branches. The activity of each thermoeffector is triggered by a unique combination of shell and core Tbs. Temperature-dependent phase transitions in thermosensory neurons cause sequential activation of all neurons of the corresponding thermoeffector loop and eventually a thermoeffector response. No computation of an integrated Tb or its comparison with an obvious or hidden set point of a unified system is necessary. Coordination between thermoeffectors is achieved through their common controlled variable, Tb. The described model incorporates Kobayashi’s views, but Kobayashi’s proposal to eliminate the term sensor is rejected. A case against the term set point is also made. Because this term is historically associated with a unified control system, it is more misleading than informative. The term balance point is proposed to designate the regulated level of Tb and to attract attention to the multiple feedback, feedforward, and open-loop components that contribute to thermal balance.
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Affiliation(s)
- Andrej A Romanovsky
- Systemic Inflammation Laboratory, Trauma Research, St. Joseph's Hospital and Medical Center, Phoenix, AZ 85013, USA.
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