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Notley SR, Mitchell D, Taylor NAS. A century of exercise physiology: concepts that ignited the study of human thermoregulation. Part 3: Heat and cold tolerance during exercise. Eur J Appl Physiol 2024; 124:1-145. [PMID: 37796292 DOI: 10.1007/s00421-023-05276-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Accepted: 07/04/2023] [Indexed: 10/06/2023]
Abstract
In this third installment of our four-part historical series, we evaluate contributions that shaped our understanding of heat and cold stress during occupational and athletic pursuits. Our first topic concerns how we tolerate, and sometimes fail to tolerate, exercise-heat stress. By 1900, physical activity with clothing- and climate-induced evaporative impediments led to an extraordinarily high incidence of heat stroke within the military. Fortunately, deep-body temperatures > 40 °C were not always fatal. Thirty years later, water immersion and patient treatments mimicking sweat evaporation were found to be effective, with the adage of cool first, transport later being adopted. We gradually acquired an understanding of thermoeffector function during heat storage, and learned about challenges to other regulatory mechanisms. In our second topic, we explore cold tolerance and intolerance. By the 1930s, hypothermia was known to reduce cutaneous circulation, particularly at the extremities, conserving body heat. Cold-induced vasodilatation hindered heat conservation, but it was protective. Increased metabolic heat production followed, driven by shivering and non-shivering thermogenesis, even during exercise and work. Physical endurance and shivering could both be compromised by hypoglycaemia. Later, treatments for hypothermia and cold injuries were refined, and the thermal after-drop was explained. In our final topic, we critique the numerous indices developed in attempts to numerically rate hot and cold stresses. The criteria for an effective thermal stress index were established by the 1930s. However, few indices satisfied those requirements, either then or now, and the surviving indices, including the unvalidated Wet-Bulb Globe-Thermometer index, do not fully predict thermal strain.
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Affiliation(s)
- Sean R Notley
- Defence Science and Technology Group, Department of Defence, Melbourne, Australia
- School of Human Kinetics, University of Ottawa, Ottawa, Canada
| | - Duncan Mitchell
- Brain Function Research Group, School of Physiology, University of the Witwatersrand, Johannesburg, South Africa
- School of Human Sciences, University of Western Australia, Crawley, Australia
| | - Nigel A S Taylor
- Research Institute of Human Ecology, College of Human Ecology, Seoul National University, Seoul, Republic of Korea.
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Notley SR, Mitchell D, Taylor NAS. A century of exercise physiology: concepts that ignited the study of human thermoregulation. Part 1: Foundational principles and theories of regulation. Eur J Appl Physiol 2023; 123:2379-2459. [PMID: 37702789 DOI: 10.1007/s00421-023-05272-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Accepted: 06/30/2023] [Indexed: 09/14/2023]
Abstract
This contribution is the first of a four-part, historical series encompassing foundational principles, mechanistic hypotheses and supported facts concerning human thermoregulation during athletic and occupational pursuits, as understood 100 years ago and now. Herein, the emphasis is upon the physical and physiological principles underlying thermoregulation, the goal of which is thermal homeostasis (homeothermy). As one of many homeostatic processes affected by exercise, thermoregulation shares, and competes for, physiological resources. The impact of that sharing is revealed through the physiological measurements that we take (Part 2), in the physiological responses to the thermal stresses to which we are exposed (Part 3) and in the adaptations that increase our tolerance to those stresses (Part 4). Exercising muscles impose our most-powerful heat stress, and the physiological avenues for redistributing heat, and for balancing heat exchange with the environment, must adhere to the laws of physics. The first principles of internal and external heat exchange were established before 1900, yet their full significance is not always recognised. Those physiological processes are governed by a thermoregulatory centre, which employs feedback and feedforward control, and which functions as far more than a thermostat with a set-point, as once was thought. The hypothalamus, today established firmly as the neural seat of thermoregulation, does not regulate deep-body temperature alone, but an integrated temperature to which thermoreceptors from all over the body contribute, including the skin and probably the muscles. No work factor needs to be invoked to explain how body temperature is stabilised during exercise.
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Affiliation(s)
- Sean R Notley
- Defence Science and Technology Group, Department of Defence, Melbourne, Australia
- School of Human Kinetics, University of Ottawa, Ottawa, Canada
| | - Duncan Mitchell
- Brain Function Research Group, School of Physiology, University of the Witwatersrand, Johannesburg, South Africa
- School of Human Sciences, University of Western Australia, Crawley, Australia
| | - Nigel A S Taylor
- Research Institute of Human Ecology, College of Human Ecology, Seoul National University, Seoul, Republic of Korea.
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Leisengang S, Nürnberger F, Ott D, Murgott J, Gerstberger R, Rummel C, Roth J. Primary culture of the rat spinal dorsal horn: a tool to investigate the effects of inflammatory stimulation on the afferent somatosensory system. Pflugers Arch 2020; 472:1769-1782. [PMID: 33098464 PMCID: PMC7691309 DOI: 10.1007/s00424-020-02478-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 08/28/2020] [Accepted: 10/14/2020] [Indexed: 02/06/2023]
Abstract
One maladaptive consequence of inflammatory stimulation of the afferent somatosensory system is the manifestation of inflammatory pain. We established and characterized a neuroglial primary culture of the rat superficial dorsal horn (SDH) of the spinal cord to test responses of this structure to neurochemical, somatosensory, or inflammatory stimulation. Primary cultures of the rat SDH consist of neurons (43%), oligodendrocytes (35%), astrocytes (13%), and microglial cells (9%). Neurons of the SDH responded to cooling (7%), heating (18%), glutamate (80%), substance P (43%), prostaglandin E2 (8%), and KCl (100%) with transient increases in the intracellular calcium [Ca2+]i. Short-term stimulation of SDH primary cultures with LPS (10 μg/ml, 2 h) caused increased expression of pro-inflammatory cytokines, inflammatory transcription factors, and inducible enzymes responsible for inflammatory prostaglandin E2 synthesis. At the protein level, increased concentrations of tumor necrosis factor-α (TNFα) and interleukin-6 (IL-6) were measured in the supernatants of LPS-stimulated SDH cultures and enhanced TNFα and IL-6 immunoreactivity was observed specifically in microglial cells. LPS-exposed microglial cells further showed increased nuclear immunoreactivity for the inflammatory transcription factors NFκB, NF-IL6, and pCREB, indicative of their activation. The short-term exposure to LPS further caused a reduction in the strength of substance P as opposed to glutamate-evoked Ca2+-signals in SDH neurons. However, long-term stimulation with a low dose of LPS (0.01 μg/ml, 24 h) resulted in a significant enhancement of glutamate-induced Ca2+ transients in SDH neurons, while substance P-evoked Ca2+ signals were not influenced. Our data suggest a critical role for microglial cells in the initiation of inflammatory processes within the SDH of the spinal cord, which are accompanied by a modulation of neuronal responses.
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Affiliation(s)
- Stephan Leisengang
- Department of Veterinary Physiology and Biochemistry, Justus-Liebig-University Giessen, Frankfurter Strasse 100, 35392, Giessen, Germany.,Center for Mind, Brain and Behavior - CMBB, Philipps-University Marburg, Marburg, Germany.,Center for Mind, Brain and Behavior - CMBB, Justus-Liebig-University of Giessen, Giessen, Germany
| | - Franz Nürnberger
- Department of Veterinary Physiology and Biochemistry, Justus-Liebig-University Giessen, Frankfurter Strasse 100, 35392, Giessen, Germany
| | - Daniela Ott
- Department of Veterinary Physiology and Biochemistry, Justus-Liebig-University Giessen, Frankfurter Strasse 100, 35392, Giessen, Germany
| | - Jolanta Murgott
- Department of Veterinary Physiology and Biochemistry, Justus-Liebig-University Giessen, Frankfurter Strasse 100, 35392, Giessen, Germany
| | - Rüdiger Gerstberger
- Department of Veterinary Physiology and Biochemistry, Justus-Liebig-University Giessen, Frankfurter Strasse 100, 35392, Giessen, Germany
| | - Christoph Rummel
- Department of Veterinary Physiology and Biochemistry, Justus-Liebig-University Giessen, Frankfurter Strasse 100, 35392, Giessen, Germany.,Center for Mind, Brain and Behavior - CMBB, Philipps-University Marburg, Marburg, Germany.,Center for Mind, Brain and Behavior - CMBB, Justus-Liebig-University of Giessen, Giessen, Germany
| | - Joachim Roth
- Department of Veterinary Physiology and Biochemistry, Justus-Liebig-University Giessen, Frankfurter Strasse 100, 35392, Giessen, Germany. .,Center for Mind, Brain and Behavior - CMBB, Philipps-University Marburg, Marburg, Germany. .,Center for Mind, Brain and Behavior - CMBB, Justus-Liebig-University of Giessen, Giessen, Germany.
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Taylor NAS, Notley SR, Lindinger MI. Heat adaptation in humans: the significance of controlled and regulated variables for experimental design and interpretation. Eur J Appl Physiol 2020; 120:2583-2595. [DOI: 10.1007/s00421-020-04489-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Accepted: 09/03/2020] [Indexed: 01/27/2023]
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Meghana VS, Vasudevarao SB, Kamath SS. The effect of combination of warm intravenous fluid infusion and forced air warming versus forced air warming alone on maternal temperature and shivering during cesarian delivery under spinal anesthesia. Ann Afr Med 2020; 19:137-143. [PMID: 32499471 PMCID: PMC7453949 DOI: 10.4103/aam.aam_58_19] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Objective Administration of warm intravenous (IV) fluid infusion and use of forced air warmers is the most easy and physiologically viable method for maintaining normothermia during surgery and postsurgical periods This study was conducted to assess the effect of combination of active warming (AW) methods namely warm IV fluid infusion and forced air warming versus forced air warming only (WA) on maternal temperature during elective C-delivery under spinal anesthesia. Materials and Methods A total of 100 patients scheduled for elective c-section were grouped into those who received both warmed IV fluid infusion and forced air warmer (Combination of active warming WI= 50) and those who received only forced air warmer (WA = 50). Core body temperature and shivering incidence were recorded using a tympanic thermometer from prespinal till the end of surgery every 10 min and in postanesthesia care unit (PACU) at 0, 15, and 30 min. Results Core temperature showed statistically significant difference in 15, 35, 45, and 55 min between air warmer and warm infusion groups and in PACU at 0, 15, and 30 min, it was statistically significant (P = 0.000) among WI group (mean temperature = 36.79°C) when compared to WA group (mean temperature = 35.96°C). There was a lower incidence of shivering in WI compared to WA group, which is statistically significant. Conclusion Combination of warm Intravenous fluid infusion and Forced air warming is better than forced air warming alone. In maintaining near normal maternal core body temperature during elective cesarean section following spinal anesthesia. Combined warming method also reduces shivering incidence.
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Affiliation(s)
- V S Meghana
- Department of Anaesthesia, KMC Mangalore, Manipal Academy of Higher Education, Mangalore, Karnataka, India
| | - Sunil Baikadi Vasudevarao
- Department of Anaesthesia, KMC Mangalore, Manipal Academy of Higher Education, Mangalore, Karnataka, India
| | - Shaila S Kamath
- Department of Anaesthesia, KMC Mangalore, Manipal Academy of Higher Education, Mangalore, Karnataka, India
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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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Abstract
The mammalian skin is innervated by cold-sensitive afferent neurons. These neurons exhibit ongoing activity at temperatures between ~10 and 42°C, are activated by innocuous cold stimuli, inhibited by warm stimuli and are mechanoinsensitive. Their axons are small-diameter myelinated (Aδ-) fibers in primates and unmyelinated (C-) fibers in nonprimate mammals. The mammalian skin is innervated by warm-sensitive afferent neurons. The density of innervation by these neurons is lower than that by cold-sensitive afferents. They exhibit ongoing activity between ~38 and 48°C, are activated by warm stimuli, inhibited by cold stimuli, and are mechanoinsensitive. Their axons are unmyelinated (C-) fibers. Cold-sensitive unmyelinated afferent neurons exhibit prominent cold sensitivity of their axons (in rats). The discharge pattern of the cutaneous cold-sensitive afferent neurons is fully preserved after nerve injury. Ongoing impulse activity and cold-evoked impulses originate ectopically at the nerve injury site. Deep somatic tissues and viscera are innervated by thermosensitive afferent neurons. Most are warm-sensitive and mechanoinsensitive and have unmyelinated axons. These afferent neurons have only rarely and incompletely been studied, e.g., in the upper gastrointestinal tract, the liver (both vagal afferents), the dorsal abdominal wall, and the skeletal muscle. Spinal cord warm sensitivity may be mediated by cutaneous afferent neurons with unmyelinated axons that are excited by spinal cord warming.
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Affiliation(s)
- Wilfrid Jänig
- Institute of Physiology, Christian-Albrechts University of Kiel, Kiel, Germany.
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Seo JY, Lim CM, Kim YH, Ha KY. Pure distraction injury of T1-2 with quad fever. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2017; 28:1044-1050. [PMID: 28776131 DOI: 10.1007/s00586-017-5232-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Revised: 07/17/2017] [Accepted: 07/19/2017] [Indexed: 10/19/2022]
Abstract
INTRODUCTION We report a pure distraction injury of the upper thoracic spine and uncontrolled hyperthermia without an infectious cause. Quad fever appears in the first several weeks to months after a cervical or upper thoracic SCI and is characterized by an extreme elevation in body core temperature beyond 40 °C without an infectious cause. Discriminating between infectious and noninfectious causes is important, and a thorough clinical assessment is required. MATERIALS AND METHODS A 52-year-old male visited the emergency room complaining of back pain with complete paralysis [American Spinal Injury Association (ASIA) A] of both lower extremities after a pedestrian-motor vehicle accident. He had trouble breathing due to a hemothorax and flail chest caused by fractures of the right second to eleventh and left fourth to seventh ribs. A computed tomography scan revealed severe distraction of the T1-2 intervertebral space. A magnetic resonance image showed signal changes in the spinal cord and a clean-cut margin between the T1-2 disc and T2 body. The neurological level of injury was C8 upon the initial neurological assessment. Emergency surgery was performed. C6-T3 posterior instrumentation and an autologous iliac bone graft were performed. RESULTS After surgery, the core temperature increased gradually to above 38.0 °C on post-trauma day 4 and increased to 40.8 °C on post-trauma day 7. None of the repeated aerobic, anaerobic, or fungal cultures of the blood, tracheal aspirate, line tips, urine, or stool was positive until post-trauma day 21, when Candida tropicalis was identified in the urine culture. On post-trauma day 63, the blood pressure, pulse, and body temperature stabilized and the patient was transferred to the general ward. At post-trauma year 6, the injury state was still complete and the neurological level of injury was changed to C4. CONCLUSIONS Based on the Grand Round case and relevant literature, we discuss the case of pure distraction injury of T1-2 with quad fever. Spinal surgeons should be knowledgeable regarding quad fever as well as the differential diagnoses and treatment strategies.
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Affiliation(s)
- Jun-Yeong Seo
- Department of Orthopaedic Surgery, Jeju National University Hospital, School of Medicine, Jeju National University, Jeju, Korea
| | - Chae-Moon Lim
- Department of Orthopaedic Surgery, Jeju National University Hospital, School of Medicine, Jeju National University, Jeju, Korea
| | - Young-Hoon Kim
- Department of Orthopaedic Surgery, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, 222 Banpo-dae-ro, Seocho-Gu, Seoul, 137-701, Korea
| | - Kee-Yong Ha
- Department of Orthopaedic Surgery, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, 222 Banpo-dae-ro, Seocho-Gu, Seoul, 137-701, Korea.
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Sumathy S, Parmar PN. Effect of a Single Musical Cakra Activation Manoeuvre on Body Temperature: An Exploratory Study. Anc Sci Life 2017; 36:3-5. [PMID: 28182030 PMCID: PMC5255968 DOI: 10.4103/0257-7941.195414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Cakra activation/balancing and music therapy are part of the traditional Indian healing system. Little is known about effect of musical (vocal) technique of cakra activation on body temperature. We conducted a single-session exploratory study to evaluate effects of a single musical (vocal) cakra activation manoeuvre on body temperature in controlled settings. Seven healthy adults performed a single musical (vocal) cakra activation manoeuvre for approximately 12 minutes in controlled environmental conditions. Pre- and post-manoeuvre body temperatures were recorded with a clinical mercury thermometer. After a single manoeuvre, increase in body temperature was recorded in all seven subjects. The range of increase in body temperature was from 0.2°F to 1.4°F; with mean temperature rise being 0.5°F and median temperature rise being 0.4°F. We conclude that a single session of musical (vocal) technique of cakra activation elevated body temperatures in all 7 subjects. Further research is required to study effects of various cakra activation techniques on body temperature and other physiological parameters.
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Affiliation(s)
- Sundar Sumathy
- Center for Music Therapy Education and Research, Mahatma Gandhi Medical College, Sri Balaji Vidyapeeth University, Puducherry, India
| | - Parin N Parmar
- Research Associate and Faculty, Chennai School of Music Therapy, Chennai, Tamil Nadu, India
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Conway A. A Review of the Effects of Sedation on Thermoregulation: Insights for the Cardiac Catheterization Laboratory. J Perianesth Nurs 2016; 31:226-36. [DOI: 10.1016/j.jopan.2014.07.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Revised: 04/10/2014] [Accepted: 07/31/2014] [Indexed: 12/21/2022]
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Brock JA, McAllen RM. Spinal cord thermosensitivity: An afferent phenomenon? Temperature (Austin) 2016; 3:232-239. [PMID: 27857953 PMCID: PMC4964996 DOI: 10.1080/23328940.2016.1157665] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Revised: 02/19/2016] [Accepted: 02/19/2016] [Indexed: 11/21/2022] Open
Abstract
We review the evidence for thermoregulatory temperature sensors in the mammalian spinal cord and reach the following conclusions. 1) Spinal cord temperature contributes physiologically to temperature regulation. 2) Parallel anterolateral ascending pathways transmit signals from spinal cooling and spinal warming: they overlap with the respective axon pathways of the dorsal horn neurons that are driven by peripheral cold- and warm-sensitive afferents. 3) We hypothesize that these ‘cold’ and ‘warm’ ascending pathways transmit all extracranial thermosensory information to the brain. 4) Cutaneous cold afferents can be activated not only by cooling the skin but also by cooling sites along their axons: we consider that this is functionally insignificant in vivo. 5) By a presynaptic action on their central terminals, local spinal cooling enhances neurotransmission from incoming ‘cold’ afferent action potentials to second order neurons in the dorsal horn; this effect disappears when the spinal cord is warm. 6) Spinal warm sensitivity is due to warm-sensitive miniature vesicular transmitter release from afferent terminals in the dorsal horn: this effect is powerful enough to excite second order neurons in the ‘warm’ pathway independently of any incoming sensory traffic. 7) Distinct but related presynaptic mechanisms at cold- and warm-sensitive afferent terminals can thus account for the thermoregulatory actions of spinal cord temperature.
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Affiliation(s)
- James A Brock
- Department of Anatomy and Neuroscience, University of Melbourne , Parkville, Victoria, Australia
| | - Robin M McAllen
- Department of Anatomy and Neuroscience, University of Melbourne, Parkville, Victoria, Australia; Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
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Therapeutic Recruitment of Thermoregulation in Humans by Selective Thermal Stimulation along the Spine. ADVANCES IN HEAT TRANSFER 2015. [DOI: 10.1016/bs.aiht.2015.08.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Considerations for the measurement of core, skin and mean body temperatures. J Therm Biol 2014; 46:72-101. [DOI: 10.1016/j.jtherbio.2014.10.006] [Citation(s) in RCA: 228] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Revised: 10/24/2014] [Accepted: 10/27/2014] [Indexed: 11/23/2022]
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Abstract
The purpose of this review is to describe the unique anatomical and physiological features of the hands and feet that support heat conservation and dissipation, and in so doing, highlight the importance of these appendages in human thermoregulation. For instance, the surface area to mass ratio of each hand is 4-5 times greater than that of the body, whilst for each foot, it is ~3 times larger. This characteristic is supported by vascular responses that permit a theoretical maximal mass flow of thermal energy of 6.0 W (136 W m(2)) to each hand for a 1 °C thermal gradient. For each foot, this is 8.5 W (119 W m(2)). In an air temperature of 27 °C, the hands and feet of resting individuals can each dissipate 150-220 W m(2) (male-female) of heat through radiation and convection. During hypothermia, the extremities are physiologically isolated, restricting heat flow to <0.1 W. When the core temperature increases ~0.5 °C above thermoneutral (rest), each hand and foot can sweat at 22-33 mL h(-1), with complete evaporation dissipating 15-22 W (respectively). During heated exercise, sweat flows increase (one hand: 99 mL h(-1); one foot: 68 mL h(-1)), with evaporative heat losses of 67-46 W (respectively). It is concluded that these attributes allow the hands and feet to behave as excellent radiators, insulators and evaporators.
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Hands and feet: physiological insulators, radiators and evaporators. Eur J Appl Physiol 2014; 114:2037-60. [DOI: 10.1007/s00421-014-2940-8] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Accepted: 06/16/2014] [Indexed: 10/25/2022]
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Iriki M, Simon E. Differential control of efferent sympathetic activity revisited. J Physiol Sci 2012; 62:275-98. [PMID: 22614392 PMCID: PMC10717676 DOI: 10.1007/s12576-012-0208-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Accepted: 04/21/2012] [Indexed: 11/27/2022]
Abstract
This article reviews 40 years of research (1970-2010) into the capability of the efferent sympathetic nervous system to display differential responsiveness. Discovered first were antagonistic changes of activity in sympathetic filaments innervating functionally different sections of the cardiovascular system in response to thermal stimulation. During the subsequent four decades of investigation, a multitude of differential sympathetic efferent response patterns were identified, ranging from opposing activity changes at the level of multi-fiber filaments innervating different organs to the level of single fibers controlling functionally different structures in the same organ. Differential sympathetic responsiveness was shown to be displayed in response to exogenous or artificial stimulation of afferent sensory fibers transmitting particular exogenous stimuli, especially those activating peripheral nociceptors. Moreover, sympathetic differentiation was found to be characteristic of autonomic responses to environmental changes by which homeostasis in the broadest sense would be challenged. Heat or cold loads or their experimental equivalents, altered composition of inspired air or changes in blood gas composition, imbalances of body fluid control, and exposure to agents challenging the immune system were shown to elicit differential efferent sympathetic response patterns which often displayed a high degree of specificity. In summary, autonomic adjustments to changes of biometeorological parameters may be considered as representative of the capability of the sympathetic nervous system to exert highly specific efferent control of organ functions by which bodily homeostasis is maintained.
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Nakamura K, Morrison SF. Central efferent pathways for cold-defensive and febrile shivering. J Physiol 2011; 589:3641-58. [PMID: 21610139 DOI: 10.1113/jphysiol.2011.210047] [Citation(s) in RCA: 158] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Shivering is a remarkable somatomotor thermogenic response that is controlled by brain mechanisms. We recorded EMGs in anaesthetized rats to elucidate the central neural circuitry for shivering and identified several brain regions whose thermoregulatory neurons comprise the efferent pathway driving shivering responses to skin cooling and pyrogenic stimulation. We simultaneously monitored parameters from sympathetic effectors: brown adipose tissue (BAT) temperature for non-shivering thermogenesis and arterial pressure and heart rate for cardiovascular responses. Acute skin cooling consistently increased EMG, BAT temperature and heart rate and these responses were eliminated by inhibition of neurons in the median preoptic nucleus (MnPO) with nanoinjection of muscimol. Stimulation of the MnPO evoked shivering, BAT thermogenesis and tachycardia, which were all reversed by antagonizing GABA(A) receptors in the medial preoptic area (MPO). Inhibition of neurons in the dorsomedial hypothalamus (DMH) or rostral raphe pallidus nucleus (rRPa) with muscimol or activation of 5-HT1A receptors in the rRPa with 8-OH-DPAT eliminated the shivering, BAT thermogenic, tachycardic and pressor responses evoked by skin cooling or by nanoinjection of prostaglandin (PG) E2, a pyrogenic mediator, into the MPO. These data are summarized with a schematic model in which the shivering as well as the sympathetic responses for cold defence and fever are driven by descending excitatory signalling through the DMH and the rRPa, which is under a tonic inhibitory control from a local circuit in the preoptic area. These results provide the interesting notion that, under the demand for increasing levels of heat production, parallel central efferent pathways control the somatic and sympathetic motor systems to drive thermogenesis.
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Affiliation(s)
- Kazuhiro Nakamura
- Career-Path Promotion Unit for Young Life Scientists, Kyoto University, Yoshida-Konoe-cho, Sakyo-ku, Kyoto 606-8501, Japan.
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Bandschapp O, Iaizzo PA. Induction of therapeutic hypothermia requires modulation of thermoregulatory defenses. Ther Hypothermia Temp Manag 2011; 1:77-85. [PMID: 24716997 DOI: 10.1089/ther.2010.0010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Hypothermia has been linked to beneficial neurologic outcomes in different clinical situations and its therapeutic value is considered important. For example, in asphyctic neonates and in patients with out-of-hospital cardiac arrest (with ventricular fibrillation as the initial cardiac rhythm), rapid installation of hypothermia has been reported to add substantial therapeutic benefits over nonthermal standard treatments. Yet, in other groups of patients in which the application of therapeutic hypothermia may be applied with clinical benefits, the optimization of therapy remains less straightforward, as the body possesses vigorous defense mechanisms to protect it from inducing hypothermia, that is, especially in conscious patients and/or in those in which the hypothalamus remains intact, such as stroke patients or patients who suffer a myocardial infarction or spinal cord injury. This overview summarizes the body's primary reactions to hypothermia and the defense mechanisms available or evoked. Then, clinically applicable ways to overcome these forceful cold defenses of the body are described to ensure both an optimal induction process for therapeutic hypothermia and maximal subjective comfort for these conscious patients.
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Affiliation(s)
- Oliver Bandschapp
- Departments of Surgery, Anesthesiology, and Integrative Biology and Physiology, University of Minnesota , Minneapolis, Minnesota
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Jessen C. Interaction of Body Temperatures in Control of Thermoregulatory Effector Mechanisms. Compr Physiol 2011. [DOI: 10.1002/cphy.cp040107] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Mitchell JH, Schmidt RF. Cardiovascular Reflex Control by Afferent Fibers from Skeletal Muscle Receptors. Compr Physiol 2011. [DOI: 10.1002/cphy.cp020317] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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Flouris AD. Functional architecture of behavioural thermoregulation. Eur J Appl Physiol 2010; 111:1-8. [DOI: 10.1007/s00421-010-1602-8] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/30/2010] [Indexed: 10/19/2022]
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Kanosue K, Crawshaw LI, Nagashima K, Yoda T. Concepts to utilize in describing thermoregulation and neurophysiological evidence for how the system works. Eur J Appl Physiol 2009; 109:5-11. [PMID: 19882166 DOI: 10.1007/s00421-009-1256-6] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/08/2009] [Indexed: 11/28/2022]
Abstract
We would like to emphasize about the system involved with homeostatic maintenance of body temperature. First, the primary mission of the thermoregulatory system is to defend core temperature (T (core)) against changes in ambient temperature (T (a)), the most frequently encountered disturbance for the system. T (a) should be treated as a feedforward input to the system, which has not been adequately recognized by thermal physiologists. Second, homeostatic demands from outside the thermoregulatory system may require or produce an altered T (core), such as fever (demand from the immune system). There are also conditions where some thermoregulatory effectors might be better not recruited due to demands from other homeostatic systems, such as during dehydration or fasting. Third, many experiments have supported the original assertion of Satinoff that multiple thermoregulatory effectors are controlled by different and relatively independent neuronal circuits. However, it would also be of value to be able to characterize strictly regulatory properties of the entire system by providing a clear definition for the level of regulation. Based on the assumption that T (core) is the regulated variable of the thermoregulatory system, regulated T (core) is defined as the T (core) that pertains within the range of normothermic T (a) (Gordon in temperature and toxicology: an integrative, comparative, and environmental approach, CRC Press, Boca Raton, 2005), i.e., the T (a) range in which an animal maintains a stable T (core). The proposed approach would facilitate the categorization and evaluation of how normal biological alterations, physiological stressors, and pathological conditions modify temperature regulation. In any case, of overriding importance is to recognize the means by which an alteration in T (core) (and modification of associated effector activities) increases the overall viability of the organism.
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Affiliation(s)
- Kazuyuki Kanosue
- Faculty of Sport Sciences, Waseda University, Mikajima 2-579-15, Tokorozawa, Saitama, Japan.
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Ulger F, Dilek A, Karakaya D, Senel A, Sarihasan B. Fatal fever of unknown origin in acute cervical spinal cord injury: five cases. J Spinal Cord Med 2009; 32:343-8. [PMID: 19810636 PMCID: PMC2718819 DOI: 10.1080/10790268.2009.11760788] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
BACKGROUND/OBJECTIVE Patients with traumatic upper thoracic and cervical spinal cord injuries are at increased risk for the development of autonomic dysfunction, including thermodysregulation. Thermoregulation is identified as an autonomic function, although the exact mechanisms of thermodysregulation have not been completely recognized. Quad fever is a hyperthermic thermoregulatory disorder that occurs in people with acute cervical and upper thoracic spinal cord injuries. First described in 1982, it has not been widely discussed in the literature. METHODS Case reports of 5 patients with cervical spinal cord injury (SCI). RESULTS Five of 18 patients (28%) with acute cervical SCI who were admitted during a 1-year period had fatal complications caused by persistent hyperthermia of unknown origin. CONCLUSIONS Patients with acute traumatic cervical and upper thoracic SCI are at risk for thermoregulatory dysfunction. Changes in the hypothalamic axis may be implicated, especially in the light of modification in hypothalamic afferent nerves, but this hypothesis has not yet been explored. Thermodysregulation may be an early sign of autonomic dysfunction. A comprehensive guideline is needed for the management of elevated body temperature in critically ill patients with cervical SCI, because this condition may be fatal.
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Affiliation(s)
- Fatma Ulger
- 1Department of Anesthesiology and Reanimation, 2Department of Neurosurgery Ondokuz Mayis University, Kurupelit, Samsun, Turkey
| | - Ahmet Dilek
- 1Department of Anesthesiology and Reanimation, 2Department of Neurosurgery Ondokuz Mayis University, Kurupelit, Samsun, Turkey
| | - Deniz Karakaya
- 1Department of Anesthesiology and Reanimation, 2Department of Neurosurgery Ondokuz Mayis University, Kurupelit, Samsun, Turkey
| | - Alparslan Senel
- 1Department of Anesthesiology and Reanimation, 2Department of Neurosurgery Ondokuz Mayis University, Kurupelit, Samsun, Turkey
| | - Binnur Sarihasan
- 1Department of Anesthesiology and Reanimation, 2Department of Neurosurgery Ondokuz Mayis University, Kurupelit, Samsun, Turkey
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Schlereth T, Dieterich M, Birklein F. Hyperhidrosis--causes and treatment of enhanced sweating. DEUTSCHES ARZTEBLATT INTERNATIONAL 2009; 106:32-7. [PMID: 19564960 DOI: 10.3238/arztebl.2009.0032] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2008] [Accepted: 11/03/2008] [Indexed: 11/27/2022]
Abstract
BACKGROUND Basically two types of sweating exist: thermoregulatory and emotional sweating. They are controlled by different centers: thermo regulatory sweating is regulated predominantly by the hypothalamus, emotional sweating predominantly by the limbic system. Enhanced sweating, called hyperhidrosis, can be generalized or focal. Primary focal hyperhidrosis is the most common type and affects the axillae, hands, feet, and face--areas principally involved in emotional sweating. Secondary hyperhidrosis develops due to dysfunction of the central or peripheral nervous system. METHODS Review based on a selective search of the literature via Medline and on the guidelines of the Association of the Scientific Medical Societies in Germany (Arbeitsgemeinschaft der wissenschaftlichen medizinischen Fachgesellschaften [AWMF]). RESULTS Various conservative and surgical treatments exist for hyperhidrosis. Conservative treatment options are the local application of aluminum chloride, tap water iontophoresis, and the intracutaneous injection of botulinum toxin. Surgical approaches include endoscopic sympathectomy and axillary tumescent curettage and liposuction, removing the sweat glands. Systemic drugs (e.g. anticholinergic substances) can be used in the treatment of generalized hyperhidrosis. CONCLUSION A step-by-step approach is recommended for the treatment of hyperhidrosis. Local treatment options with few and minor side effects should be tried first.
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Affiliation(s)
- Tanja Schlereth
- Klinik für Neurologie, Johannes Gutenberg-Universität Mainz, Germany.
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Abstract
Most clinically available thermometers accurately report the temperature of whatever tissue is being measured. The difficulty is that no reliably core-temperature-measuring sites are completely noninvasive and easy to use-especially in patients not undergoing general anesthesia. Nonetheless, temperature can be reliably measured in most patients. Body temperature should be measured in patients undergoing general anesthesia exceeding 30 min in duration and in patients undergoing major operations during neuraxial anesthesia. Core body temperature is normally tightly regulated. All general anesthetics produce a profound dose-dependent reduction in the core temperature, triggering cold defenses, including arteriovenous shunt vasoconstriction and shivering. Anesthetic-induced impairment of normal thermoregulatory control, with the resulting core-to-peripheral redistribution of body heat, is the primary cause of hypothermia in most patients. Neuraxial anesthesia also impairs thermoregulatory control, although to a lesser extent than does general anesthesia. Prolonged epidural analgesia is associated with hyperthermia whose cause remains unknown.
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Affiliation(s)
- Daniel I Sessler
- Department of Outcomes Research, The Cleveland Clinic-P77, Cleveland, Ohio 44195, USA.
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Gajendiran M. Differential effects of spinal 5-HT1A receptor activation and 5-HT2A/2C receptor desensitization by chronic haloperidol. Prog Neuropsychopharmacol Biol Psychiatry 2007; 31:1449-55. [PMID: 17688988 DOI: 10.1016/j.pnpbp.2007.06.020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2007] [Revised: 06/22/2007] [Accepted: 06/22/2007] [Indexed: 11/16/2022]
Abstract
The effects of 7- and 21-day haloperidol treatment on the spinal serotonergic system were examined in vivo in acutely spinalized adult rats. Intravenous administration of a selective 5-HT(2A/2C) receptor agonist, (+/-)-2,5-Dimethoxy-4-iodoamphetamine hydrochloride (0.1 mg/kg) significantly increased the excitability of spinal motoneurones as reflected by increased monosynaptic mass reflex amplitude. This was significantly reduced in rats treated with haloperidol (1 mg/kg/day, i.p.) for 7 and 21 days. Administration of a 5-HT(1A/7) receptor agonist, (+/-)-8-Hydroxy dipropylaminotetraline hydrobromide (0.1 mg/kg, i.v.) significantly inhibited the monosynaptic mass reflex. This inhibition was greatly prolonged in haloperidol treated animals. These results demonstrate that the effects of haloperidol on the activation and desensitization of 5-HT(1A) and 5-HT(2A/2C) receptors respectively, may be mediated via intracellular mechanisms shared by these receptors with dopamine D(2) receptors in the mammalian spinal cord. The above serotonergic mechanisms may be partly responsible for haloperidol-induced extrapyramidal motor dysfunction.
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Affiliation(s)
- Mahadevan Gajendiran
- Department of Pharmacology, Faculty of Pharmaceutical Sciences, Science University of Tokyo, 12 Ichigaya, Funagawara-machi, Shinjuku-ku, Tokyo 162, Japan.
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Simon E. Tympanic temperature is not suited to indicate selective brain cooling in humans: a re-evaluation of the thermophysiological basics. Eur J Appl Physiol 2007; 101:19-30. [PMID: 17534647 DOI: 10.1007/s00421-007-0449-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/16/2007] [Indexed: 11/30/2022]
Abstract
Selective brain cooling in humans, with venous blood returning from the head surface as the relevant heat sink, was proposed more than two decades ago as a mechanism protecting the brain against damage in hyperthermic conditions. Brain cooling was inferred from decreases of tympanic temperature under the premise that it reflected brain temperature closely, even in conditions of external head cooling. In mammals with a well-developed carotid rete selective brain cooling and its quantitative relevance are experimentally well established by directly monitoring brain temperature. For humans, however, the dispute about the existence and physiological relevance of selective brain cooling has remained unsettled, especially, as far as arguments have been exchanged on the basis of thermophysiological data and model calculations considering brain metabolism, brain hemodynamics and the anatomical preconditions for arterio-venous heat exchange. In this essay two seminal studies in support of the existence of human selective brain cooling in the condition of exercise hyperthermia, with and without dehydration, are re-examined from two points of view: first the stringency of the working hypotheses underlying data evaluation and their subsequent fate. Second the minimum theoretical requirements for data interpretation. The working hypotheses supporting data interpretation in favor of selective brain cooling in humans were heuristic and/or had become questionable at the dates of their application; today, they may be considered as outdated. Data interpretation becomes most conclusive, if tympanic temperature simply is not taken into account.
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Affiliation(s)
- Eckhart Simon
- Max-Planck-Institute for Heart and Lung Research, W G Kerckhoff-Institute, Parkstrasse 1, 61231, Bad Nauheim, Germany.
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Garstang SV, Miller-Smith SA. Autonomic Nervous System Dysfunction After Spinal Cord Injury. Phys Med Rehabil Clin N Am 2007; 18:275-96, vi-vii. [PMID: 17543773 DOI: 10.1016/j.pmr.2007.02.003] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The autonomic nervous system (ANS) plays a key role in the regulation of many physiologic processes, mediated by supraspinal control from centers in the central nervous system. The role of autonomic dysfunction in persons with spinal cord injuries is crucial to understand because many aspects of the altered physiology seen in these individuals are directly caused by ANS dysregulation.
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Affiliation(s)
- Susan V Garstang
- Department of Physical Medicine and Rehabilitation, UMNDJ-New Jersey Medical School, 30 Bergen Street, ADMC 101, Newark, NJ 07039, USA.
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Abstract
Recent evidence suggests that neurons in the medullary raphe are critical to the activation of brown adipose tissue (BAT), the major source of nonshivering heat production in the rat. Yet it is unclear which medullary raphe cells participate in cold defense and how participating cells contribute to BAT activation. Therefore, we recorded extracellularly from raphe cells during three thermoregulatory challenges that evoked an increase in BAT temperature in anesthetized rats: central cold, ambient cold, or intracerebroventricular prostaglandin E2 (PGE2) injection. Physiologically identified serotonergic (p5HT) cell discharge increased in response to cold or PGE2 administration and was positively correlated with BAT temperature. However, none of the 147 physiologically identified non-serotonergic (non-p5HT) cells recorded responded to thermoregulatory challenges that evoked an increase in BAT temperature. To test for modulation of BAT activation by non-p5HT cells that are either excited (ON cells) or inhibited (OFF cells) by noxious cutaneous stimulation, noxious stimuli were applied during evoked BAT temperature increases. Noxious stimulation suppressed BAT activation, suggesting that cells inhibited by noxious stimulation facilitate spinal circuits controlling BAT. To test whether medullary OFF cells modulate BAT activity, the mu-opiate receptor agonist (d-Ala2, N-Me-Phe4, Gly-ol5)-enkephalin (DAMGO) was microinjected into the raphe magnus, a manipulation that selectively activates OFF cells. DAMGO microinjection blocked noxious stimulation-evoked suppression of PGE2-induced BAT temperature increases. Thus, both p5HT and non-p5HT OFF cells in the medullary raphe facilitate BAT activation in response to cold challenge or pyrogen.
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Steele SR, Martin MJ, Mullenix PS, Long WB, Gubler KD. Fatal malignant hyperpyrexia in a cervical spine- injured patient. ACTA ACUST UNITED AC 2005; 58:375-7. [PMID: 15706204 DOI: 10.1097/01.ta.0000066349.88810.97] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Scott R Steele
- Department of Surgery, Madigan Army Medical Center, Legacy Emanuel Hospital and Health Center, Portland, OR 97227, USA
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Ray B, Mallick HN, Kumar VM. Changes in sleep-wakefulness in the medial preoptic area lesioned rats: role of thermal preference. Behav Brain Res 2005; 158:43-52. [PMID: 15680193 DOI: 10.1016/j.bbr.2004.08.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2004] [Revised: 08/05/2004] [Accepted: 08/06/2004] [Indexed: 10/26/2022]
Abstract
Changes in sleep-wakefulness (S-W) were studied in adult male Wistar rats, along with body temperature (T(b)), locomotor activity (LMA) and thermal preference, after the lesion of the medial preoptic area (mPOA) with N-methyl-D-aspartic acid (NMDA). The sleep was decreased after the lesion of the mPOA, but there was recovery when the rats were given freedom to stay in an ambient temperature (T(amb)) which they preferred. When given a choice between three T(amb) (24, 27 and 30 degrees C), the rats preferred 27 degrees C before the mPOA lesion, and 24 degrees C during the initial days after the lesion. There was a shift in the thermal preference to 30 degrees C, on the fourth week after the lesion, which coincided with the considerable recovery of sleep. The preference for higher T(amb) probably helped to improve sleep, as T(amb) of 30 degrees C is known to promote sleep. When the lesioned rats were not given the freedom to select the T(amb), there was no recovery in sleep. The mPOA seems to be essential for increasing the durations of slow wave sleep (SWS) episodes, especially the light SWS (S1), as they remained shorter than the pre-lesion value, even when the rats were given freedom to stay in a preferred T(amb). The homeostatic recovery of sleep, especially the night time sleep, resulted in the disruption of circadian sleep rhythm. But, the LMA, T(b) and thermal preference maintained their diurnal variation. T(b) and LMA were elevated after the mPOA lesion and they remained so till the end of the study.
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Affiliation(s)
- Baisali Ray
- Department of Physiology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110029, India
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Osaka T. Thermogenesis elicited by skin cooling in anaesthetized rats: lack of contribution of the cerebral cortex. J Physiol 2004; 555:503-13. [PMID: 14578483 PMCID: PMC1664850 DOI: 10.1113/jphysiol.2003.053215] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2003] [Accepted: 10/22/2003] [Indexed: 11/08/2022] Open
Abstract
Non-noxious cooling stimuli were delivered to the shaved back of urethane-chloralose-anaesthetized, artificially ventilated rats using a plastic bag containing water at 24-40 degrees C. Cooling of the skin by 2-6 degrees C increased the rate of whole body oxygen consumption (.V(O(2)) and triggered electromyographic (EMG) activity recorded from the neck or femoral muscles. The cooling-induced (.V(O(2)) responses did not depend on core (colonic) temperature and followed skin temperature in a graded manner. Pretreatment with the beta-blocker propranolol (10 mg kg(-1), i.v.) greatly attenuated the (.V(O(2)) response but did not affect the EMG response. On the other hand, pretreatment with the muscle relaxant pancuronium bromide (2 mg kg(-1), i.v.) affected the (.V(O(2)) response very slightly but completely abolished the EMG activity. Accordingly, the cooling stimulus activated mainly non-shivering thermogenesis. Next, the contribution of the cerebral cortex to the cooling-induced thermogenesis was examined. Power spectral analysis of the electroencephalogram (EEG) showed that the cooling stimulus largely inhibited delta (0.5-3 Hz) waves, enhanced theta (3-8 Hz) waves, and slightly increased frequencies higher than 8 Hz. Pinching the hindpaw elicited changes in EEG similar to those elicited by skin cooling but did not increase the (.V(O(2)). Therefore, there was no relationship between changes in the EEG and the magnitude of thermogenesis. Finally, skin cooling increased the (.V(O(2)) of decorticated rats but did not increase that of decerebrated rats. The results suggest that the subcortical forebrain structure, but not cortical activation, is indispensable for non-shivering thermogenesis elicited by cooling stimulation of the skin.
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Affiliation(s)
- Toshimasa Osaka
- National Institute of Health and Nutrition, Shinjuku 162-8636, Japan.
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Alfonsi P, Adam F, Passard A, Guignard B, Sessler DI, Chauvin M. Nefopam, a nonsedative benzoxazocine analgesic, selectively reduces the shivering threshold in unanesthetized subjects. Anesthesiology 2004; 100:37-43. [PMID: 14695722 PMCID: PMC1283107 DOI: 10.1097/00000542-200401000-00010] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
BACKGROUND The analgesic nefopam does not compromise ventilation, is minimally sedating, and is effective as a treatment for postoperative shivering. The authors evaluated the effects of nefopam on the major thermoregulatory responses in humans: sweating, vasoconstriction, and shivering. METHODS Nine volunteers were studied on three randomly assigned days: (1) control (saline), (2) nefopam at a target plasma concentration of 35 ng/ml (low dose), and (3) nefopam at a target concentration of 70 ng/ml (high dose, approximately 20 mg total). Each day, skin and core temperatures were increased to provoke sweating and then reduced to elicit peripheral vasoconstriction and shivering. The authors determined the thresholds (triggering core temperature at a designated skin temperature of 34 degrees C) by mathematically compensating for changes in skin temperature using the established linear cutaneous contributions to control of each response. RESULTS Nefopam did not significantly modify the slopes for sweating (0.0 +/- 4.9 degrees C. microg-1. ml; r2 = 0.73 +/- 0.32) or vasoconstriction (-3.6 +/- 5.0 degrees C. microg-1. ml; r2 = -0.47 +/- 0.41). In contrast, nefopam significantly reduced the slope of shivering (-16.8 +/- 9.3 degrees C. microg-1. ml; r2 = 0.92 +/- 0.06). Therefore, high-dose nefopam reduced the shivering threshold by 0.9 +/- 0.4 degrees C (P < 0.001) without any discernible effect on the sweating or vasoconstriction thresholds. CONCLUSIONS Most drugs with thermoregulatory actions-including anesthetics, sedatives, and opioids-synchronously reduce the vasoconstriction and shivering thresholds. However, nefopam reduced only the shivering threshold. This pattern has not previously been reported for a centrally acting drug. That pharmacologic modulations of vasoconstriction and shivering can be separated is of clinical and physiologic interest.
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Affiliation(s)
- Pascal Alfonsi
- Department of Anesthesia, Hôpital Ambroise Paré, Assistance Publique-Hopitaux de Paris, France.
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Maloney SK, Bonomelli JM, DeSouza J. Scrotal heating stimulates panting and reduces body temperature similarly in febrile and non-febrile rams (Ovis aries). Comp Biochem Physiol A Mol Integr Physiol 2003; 135:565-73. [PMID: 12890546 DOI: 10.1016/s1095-6433(03)00139-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
It is known that heating the ram scrotum stimulates heat loss resulting in a decrease in body temperature and that during fever core temperature increases, but local scrotal thermoeffectors operate to maintain normal scrotal temperature. We have investigated whether scrotal warming influences core body temperature and the panting effector during fever generation. We measured rectal temperature, intrascrotal temperature, scrotal skin temperature and respiratory frequency in four adult Merino rams following intravascular injection of saline or lipopolysaccharide at an ambient temperature of 18-20 degrees C while scrotal skin temperature was maintained at 33 degrees C or elevated to 41 degrees C. Compared to maintaining normal scrotal temperature, heating the scrotum increased respiratory frequency and reduced rectal temperature by a similar amount following LPS as following saline. Fever was associated with decreased respiratory frequency compared to saline at both 33 and 41 degrees C scrotal temperature, suggesting that the fever was generated mainly by decreasing respiratory heat loss. We conclude that scrotal thermal afferent stimulation resulted in an offset for the set-point of body temperature regulation in both normothermic and febrile rams.
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Affiliation(s)
- Shane K Maloney
- Physiology, School of Biomedical and Chemical Science, University of Western Australia, 35 Stirling Hwy, Crawley 6009, Australia
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Owens NC, Ootsuka Y, Kanosue K, McAllen RM. Thermoregulatory control of sympathetic fibres supplying the rat's tail. J Physiol 2002; 543:849-58. [PMID: 12231643 PMCID: PMC2290547 DOI: 10.1113/jphysiol.2002.023770] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
We investigated the thermoregulatory responses of sympathetic fibres supplying the tail in urethane-anaesthetised rats. When skin and rectal temperatures were kept above 39 degrees C, tail sympathetic fibre activity was low or absent. When the trunk skin was cooled episodically by 2-7 degrees C by a water jacket, tail sympathetic activity increased in a graded fashion below a threshold skin temperature of 37.8 +/- 0.6 degrees C, whether or not core (rectal) temperature changed. Repeated cooling episodes lowered body core temperature by 1.3-3.1 degrees C, and this independently activated tail sympathetic fibre activity, in a graded fashion, below a threshold rectal temperature of 38.4 +/- 0.2 degrees C. Tail blood flow showed corresponding graded vasoconstrictor responses to skin and core cooling, albeit over a limited range. Tail sympathetic activity was more sensitive to core than to trunk skin cooling by a factor that varied widely (24-fold) between animals. Combined skin and core cooling gave additive or facilitatory responses near threshold but occlusive interactions with stronger stimuli. Unilateral warming of the preoptic area reversibly inhibited tail sympathetic activity. This was true for activity generated by either skin or core cooling. Single tail sympathetic units behaved homogeneously. Their sensitivity to trunk skin cooling was 0.3 +/- 0.08 spikes s(-1) degrees C(-1) and to core cooling was 2.2 +/- 0.5 spikes s(-1) degrees C(-1). Their maximum sustained firing rate in the cold was 1.82 +/- 0.35 spikes s(-1).
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Affiliation(s)
- N C Owens
- Howard Florey Institute of Experimental Physiology and Medicine, University of Melbourne, Victoria 3010, Australia
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Couto da Silva JM, Couto da Silva JM, Antonio Aldrete J. Body temperature and diaphoresis disturbances in a patient with arachnoiditis. Anesth Analg 2001; 93:1578-9, table of contents. [PMID: 11726448 DOI: 10.1097/00000539-200112000-00053] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
IMPLICATIONS Arachnoiditis, produced by different causes, is an inflammation of the sac containing the spinal cord and nerve roots. Patients with this disease have severe low back and leg pain, sweating and low grade fever. This case had aberrant skin temperature and sweating in different parts of the body.
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Abstract
The body temperature of homeothermic animals is regulated by systems that utilize multiple behavioral and autonomic effector responses. In the last few years, new approaches have brought us new information and new ideas about neuronal interconnections in the thermoregulatory network. Studies utilizing chemical stimulation of the preoptic area revealed both heat loss and production responses are controlled by warm-sensitive neurons. These neurons send excitatory efferent signals for the heat loss and inhibitory efferent signals for the heat production. The warm-sensitive neurons are separated and work independently to control these two opposing responses. Recent electrophysiological analysis have identified some neurons sending axons directly to the spinal cord for thermoregulatory effector control. Included are midbrain reticulospinal neurons for shivering and premotor neurons in the medulla oblongata for skin vasomotor control. As for the afferent side of the thermoregulatory network, the vagus nerve is recently paid much attention, which would convey signals for peripheral infection to the brain and be responsible for the induction of fever. The vagus nerve may also participate in thermoregulation in afebrile conditions, because some substances such as cholecyctokinin and leptin activate the vagus nerve. Although the functional role for this response is still obscure, the vagus may transfer nutritional and/or metabolic signals to the brain, affecting metabolism and body temperature.
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Affiliation(s)
- K Nagashima
- Department of Physiology, Osaka University Faculty of Medicine, School of Allied Health Sciences, Suita, Japan
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Kenney MJ, Pickar JG, Weiss ML, Saindon CS, Fels RJ. Effects of midbrain and spinal cord transections on sympathetic nerve responses to heating. Am J Physiol Regul Integr Comp Physiol 2000; 278:R1329-38. [PMID: 10801304 DOI: 10.1152/ajpregu.2000.278.5.r1329] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In the present study, we investigated the contributions of forebrain, brain stem, and spinal neural circuits to heating-induced sympathetic nerve discharge (SND) responses in chloralose-anesthetized rats. Frequency characteristics of renal and splenic SND bursts and the level of activity in these nerves were determined in midbrain-transected (superior colliculus), spinal cord-transected [first cervical vertebra (C1)], and sham-transected (midbrain and spinal cord) rats during progressive increases in colonic temperature (T(c)) from 38 to 41.6-41.7 degrees C. The following observations were made. 1) Significant increases in renal and splenic SND were observed during hyperthermia in midbrain-transected, sham midbrain-transected, C1-transected, and sham C1-transected rats. 2) Heating changed the discharge pattern of renal and splenic SND bursts and was associated with prominent coupling between renal-splenic discharge bursts in midbrain-transected, sham midbrain-transected, and sham C1-transected rats. 3) The pattern of renal and splenic SND bursts remained unchanged from posttransection recovery levels during heating in C1-transected rats. We conclude that an intact forebrain is not required for the full expression of SND responses to increased T(c) and that spinal neural systems, in the absence of supraspinal circuits, are unable to markedly alter the frequency characteristics of SND in response to acute heat stress.
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Affiliation(s)
- M J Kenney
- Department of Anatomy, Kansas State University, Manhattan, Kansas 66506, USA
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Gutiérrez-Ospina G, Jiménez-Trejo FJ, Favila R, Moreno-Mendoza NA, Granados Rojas L, Barrios FA, Díaz-Cintra S, Merchant-Larios H. Acetylcholinesterase-positive innervation is present at undifferentiated stages of the sea turtle Lepidochelis olivacea embryo gonads: implications for temperature-dependent sex determination. J Comp Neurol 1999; 410:90-8. [PMID: 10397397 DOI: 10.1002/(sici)1096-9861(19990719)410:1<90::aid-cne8>3.0.co;2-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
In embryos of different reptile species, incubation temperature triggers a cascade of endocrine events that lead to gonad sex differentiation. The cellular and molecular mechanisms by which temperature sets in motion this process are still controversial. Here, we begin evaluating the possible participation of the nervous system in temperature-dependent sex determination by showing the existence and origin of acetylcholinesterase (AchE)-positive nerve fibers in undifferentiated gonads of the Lepidochelys olivacea (L. olivacea) sea turtle putative male and female embryos, along the thermosensitive period for sex determination (TPSD; stages 20-27). AChE-positive nerve bundles and fibers were readily visualized until developmental stage 24 and thereafter. DiI injections and confocal imaging showed that some of these gonadal nerves arise from the lower thoracic and upper lumbar spinal cord levels, and might thus be sensory in nature. Because the vertebrate spinal cord is capable of integrating by itself thermoregulatory responses with no intervention of uppermost levels of the central nervous system, we also evaluated spinal cord maturation during the TPSD. The maturation of the spinal cord was more advanced in putative female than in male embryos, when sex determination is taking place for each sex; this process starts and ends earlier in male than in female embryos. Together these observations open the possibility that the spinal cord and the innervation derived from it could play a direct role in driving or modulating the process of temperature-dependent gonad sex determination and/or differentiation, particularly in female L. olivacea embryos.
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Affiliation(s)
- G Gutiérrez-Ospina
- Department of Development Neurobiology, Center of Neurobiology, National University of México, Campus UNAM-UAQ-Juriquilla, Querétaro, México
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Schmid HA, Riedel W, Simon E. Role of nitric oxide in temperature regulation. PROGRESS IN BRAIN RESEARCH 1998; 115:87-110. [PMID: 9632931 DOI: 10.1016/s0079-6123(08)62031-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- H A Schmid
- Max-Planck-Institute for Physiological and Clinical Research, William G. Kerckhoff-Institute, Bad Nauheim, Germany.
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Pierau FK, Sann H, Yakimova KS, Haug P. Plasticity of hypothalamic temperature-sensitive neurons. PROGRESS IN BRAIN RESEARCH 1998; 115:63-84. [PMID: 9632930 DOI: 10.1016/s0079-6123(08)62030-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- F K Pierau
- Max-Planck-Institute for Physiological and Clinical Research, William G. Kerckhoff-Institute, Bad Nauheim, Germany.
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Simon E, Schmid HA, Pehl U. Spinal neuronal thermosensitivity in vivo and in vitro in relation to hypothalamic neuronal thermosensitivity. PROGRESS IN BRAIN RESEARCH 1998; 115:25-47. [PMID: 9632928 DOI: 10.1016/s0079-6123(08)62028-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
In the spinal cord, temperature signals are generated which serve as specific inputs in the central nervous control of body temperature. Because of the spatially distinct organization of afferent and efferent neuronal systems at the spinal level, the afferent pathway for temperature signal transmission could be identified in vivo in the ascending, anterior and lateral tracts with a relationship of about 75:25% between warm and cold sensitive neuraxons. Analysis of spinal neuronal thermosensitivity in vitro on spinal cord tissue slices has been concerned, so far, with the superficial laminae of the dorsal horn as the site of origin of ascending nerve fibers conveying mostly temperature and pain signals, and with lamina X as a site of origin of afferent as well as efferent neurons. A relationship of about 95:5% between warm and cold sensitive neurons was found at the segmental level, indicating that warm sensitivity is the prevailing, primary property of spinal neurons, whereas cold sensitivity seems to be mainly generated by synaptic interaction as a secondary modality. Dynamic responses to temperature changes were frequently displayed in vitro at the spinal segmental level in lamina I + II but not in lamina X, even by neurons whose static activity was little influenced by local temperature. Dynamic thermosensitivity was found less frequently in ascending tract neuraxons and was not observed in hypothalamic neurons receiving temperature signal inputs from the spinal cord, and thus, does not seem to be relevant for the thermosensory function of spinal cord neurons, unlike peripheral warm and cold receptors. A majority of spinal warm sensitive neurons displayed both static and dynamic warm sensitivity as an inherent property after synaptic blockade. In the further analysis of spinal cord thermosensitivity, the in vitro approach permits application of the same electrophysiological and neuropharmacological methods as were established for the analysis of hypothalamic thermosensitivity. In addition, the topography of the spinal cord will provide additional structural and possibly histochemical information to characterize the functions of neurons independently of their thermal properties.
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Affiliation(s)
- E Simon
- Max-Planck-Institute for Physiological and Clinical Research, William G. Kerckhoff-Institute, Bad Nauheim, Germany
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Hori T, Katafuchi T. Cell biology and the functions of thermosensitive neurons in the brain. PROGRESS IN BRAIN RESEARCH 1998; 115:9-23. [PMID: 9632927 DOI: 10.1016/s0079-6123(08)62027-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- T Hori
- Department of Physiology, Kyushu University Faculty of Medicine, Fukuoka, Japan.
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