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Kiyatkin EA. Brain temperature and its role in physiology and pathophysiology: Lessons from 20 years of thermorecording. Temperature (Austin) 2019; 6:271-333. [PMID: 31934603 PMCID: PMC6949027 DOI: 10.1080/23328940.2019.1691896] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 10/29/2019] [Accepted: 10/30/2019] [Indexed: 12/11/2022] Open
Abstract
It is well known that temperature affects the dynamics of all physicochemical processes governing neural activity. It is also known that the brain has high levels of metabolic activity, and all energy used for brain metabolism is finally transformed into heat. However, the issue of brain temperature as a factor reflecting neural activity and affecting various neural functions remains in the shadow and is usually ignored by most physiologists and neuroscientists. Data presented in this review demonstrate that brain temperature is not stable, showing relatively large fluctuations (2-4°C) within the normal physiological and behavioral continuum. I consider the mechanisms underlying these fluctuations and discuss brain thermorecording as an important tool to assess basic changes in neural activity associated with different natural (sexual, drinking, eating) and drug-induced motivated behaviors. I also consider how naturally occurring changes in brain temperature affect neural activity, various homeostatic parameters, and the structural integrity of brain cells as well as the results of neurochemical evaluations conducted in awake animals. While physiological hyperthermia appears to be adaptive, enhancing the efficiency of neural functions, under specific environmental conditions and following exposure to certain psychoactive drugs, brain temperature could exceed its upper limits, resulting in multiple brain abnormalities and life-threatening health complications.
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Affiliation(s)
- Eugene A Kiyatkin
- Behavioral Neuroscience Branch, National Institute on Drug Abuse - Intramural Research Program, National Institutes of Health, Baltimore, MD, USA
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Kumar H, Lee SH, Kim KT, Zeng X, Han I. TRPV4: a Sensor for Homeostasis and Pathological Events in the CNS. Mol Neurobiol 2018; 55:8695-8708. [PMID: 29582401 DOI: 10.1007/s12035-018-0998-8] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2017] [Accepted: 03/07/2018] [Indexed: 01/22/2023]
Abstract
Transient receptor potential vanilloid type 4 (TRPV4) was originally described as a calcium-permeable nonselective cation channel. TRPV4 is now recognized as a polymodal ionotropic receptor: it is a broadly expressed, nonselective cation channel (permeable to calcium, potassium, magnesium, and sodium) that plays an important role in a multitude of physiological processes. TRPV4 is involved in maintaining homeostasis, serves as an osmosensor and thermosensor, can be activated directly by endogenous or exogenous chemical stimuli, and can be activated or sensitized indirectly via intracellular signaling pathways. Additionally, TRPV4 is upregulated in a variety of pathological conditions. In this review, we focus on the role of TRPV4 in mediating homeostasis and pathological events in the central nervous system (CNS). This review is composed of three parts. Section 1 describes the role of TRPV4 in maintaining homeostatic processes, including the volume of body water, ionic concentrations, volume, and the temperature. Section 2 describes the effects of activation and inhibition of TRPV4 in the CNS. Section 3 focuses on the role of TRPV4 during pathological events in CNS.
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Affiliation(s)
- Hemant Kumar
- Department of Neurosurgery, CHA University, CHA Bundang Medical Center, Seongnam-si, Gyeonggi-do, 13496, Republic of Korea
| | - Soo-Hong Lee
- Department of Biomedical Science, CHA University, Seongnam-si, Gyeonggi-do, Republic of Korea
| | - Kyoung-Tae Kim
- Department of Neurosurgery, Kyungpook National University Hospital, 130, Dongdeok-ro, Jung-gu, Daegu, 41944, Republic of Korea
| | - Xiang Zeng
- Department of Histology and Embryology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, 510080, China.
| | - Inbo Han
- Department of Neurosurgery, CHA University, CHA Bundang Medical Center, Seongnam-si, Gyeonggi-do, 13496, Republic of Korea.
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Kiyatkin EA. Brain temperature: from physiology and pharmacology to neuropathology. HANDBOOK OF CLINICAL NEUROLOGY 2018; 157:483-504. [DOI: 10.1016/b978-0-444-64074-1.00030-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
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Xue Y, Yang Y, Tang Y, Ye M, Xu J, Zeng Y, Zhang J. In vitro thermosensitivity of rat lateral parabrachial neurons. Neurosci Lett 2016; 619:15-20. [DOI: 10.1016/j.neulet.2016.02.058] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Revised: 02/01/2016] [Accepted: 02/29/2016] [Indexed: 02/03/2023]
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Kahan J, Papadaki A, White M, Mancini L, Yousry T, Zrinzo L, Limousin P, Hariz M, Foltynie T, Thornton J. The Safety of Using Body-Transmit MRI in Patients with Implanted Deep Brain Stimulation Devices. PLoS One 2015; 10:e0129077. [PMID: 26061738 PMCID: PMC4465697 DOI: 10.1371/journal.pone.0129077] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Accepted: 05/04/2015] [Indexed: 12/02/2022] Open
Abstract
Background Deep brain stimulation (DBS) is an established treatment for patients with movement disorders. Patients receiving chronic DBS provide a unique opportunity to explore the underlying mechanisms of DBS using functional MRI. It has been shown that the main safety concern with MRI in these patients is heating at the electrode tips – which can be minimised with strict adherence to a supervised acquisition protocol using a head-transmit/receive coil at 1.5T. MRI using the body-transmit coil with a multi-channel receive head coil has a number of potential advantages including an improved signal-to-noise ratio. Study outline We compared the safety of cranial MRI in an in vitro model of bilateral DBS using both head-transmit and body-transmit coils. We performed fibre-optic thermometry at a Medtronic ActivaPC device and Medtronic 3389 electrodes during turbo-spin echo (TSE) MRI using both coil arrangements at 1.5T and 3T, in addition to gradient-echo echo-planar fMRI exposure at 1.5T. Finally, we investigated the effect of transmit-coil choice on DBS stimulus delivery during MRI. Results Temperature increases were consistently largest at the electrode tips. Changing from head- to body-transmit coil significantly increased the electrode temperature elevation during TSE scans with scanner-reported head SAR 0.2W/kg from 0.45°C to 0.79°C (p<0.001) at 1.5T, and from 1.25°C to 1.44°C (p<0.001) at 3T. The position of the phantom relative to the body coil significantly impacted on electrode heating at 1.5T; however, the greatest heating observed in any position tested remained <1°C at this field strength. Conclusions We conclude that (1) with our specific hardware and SAR-limited protocol, body-transmit cranial MRI at 1.5T does not produce heating exceeding international guidelines, even in cases of poorly positioned patients, (2) cranial MRI at 3T can readily produce heating exceeding international guidelines, (3) patients with ActivaPC Medtronic systems are safe to be recruited to future fMRI experiments performed under the specific conditions defined by our protocol, with no likelihood of confound by inappropriate stimulus delivery.
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Affiliation(s)
- Joshua Kahan
- Sobell Department of Motor Neuroscience & Movement Disorders, UCL Institute of Neurology, London, United Kingdom
- * E-mail:
| | - Anastasia Papadaki
- Lysholm Department of Neuroradiology, National Hospital for Neurology and Neurosurgery, UCLH NHS Foundation Trust, London, United Kingdom
- Department of Brain Repair and Rehabilitation, UCL Institute of Neurology, London, United Kingdom
| | - Mark White
- Lysholm Department of Neuroradiology, National Hospital for Neurology and Neurosurgery, UCLH NHS Foundation Trust, London, United Kingdom
- Department of Brain Repair and Rehabilitation, UCL Institute of Neurology, London, United Kingdom
| | - Laura Mancini
- Lysholm Department of Neuroradiology, National Hospital for Neurology and Neurosurgery, UCLH NHS Foundation Trust, London, United Kingdom
- Department of Brain Repair and Rehabilitation, UCL Institute of Neurology, London, United Kingdom
| | - Tarek Yousry
- Lysholm Department of Neuroradiology, National Hospital for Neurology and Neurosurgery, UCLH NHS Foundation Trust, London, United Kingdom
- Department of Brain Repair and Rehabilitation, UCL Institute of Neurology, London, United Kingdom
| | - Ludvic Zrinzo
- Sobell Department of Motor Neuroscience & Movement Disorders, UCL Institute of Neurology, London, United Kingdom
| | - Patricia Limousin
- Sobell Department of Motor Neuroscience & Movement Disorders, UCL Institute of Neurology, London, United Kingdom
| | - Marwan Hariz
- Sobell Department of Motor Neuroscience & Movement Disorders, UCL Institute of Neurology, London, United Kingdom
| | - Tom Foltynie
- Sobell Department of Motor Neuroscience & Movement Disorders, UCL Institute of Neurology, London, United Kingdom
| | - John Thornton
- Lysholm Department of Neuroradiology, National Hospital for Neurology and Neurosurgery, UCLH NHS Foundation Trust, London, United Kingdom
- Department of Brain Repair and Rehabilitation, UCL Institute of Neurology, London, United Kingdom
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Kiyatkin EA, Wakabayashi KT, Lenoir M. Physiological fluctuations in brain temperature as a factor affecting electrochemical evaluations of extracellular glutamate and glucose in behavioral experiments. ACS Chem Neurosci 2013; 4:652-65. [PMID: 23448428 DOI: 10.1021/cn300232m] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The rate of any chemical reaction or process occurring in the brain depends on temperature. While it is commonly believed that brain temperature is a stable, tightly regulated homeostatic parameter, it fluctuates within 1-4 °C following exposure to salient arousing stimuli and neuroactive drugs, and during different behaviors. These temperature fluctuations should affect neural activity and neural functions, but the extent of this influence on neurochemical measurements in brain tissue of freely moving animals remains unclear. In this Review, we present the results of amperometric evaluations of extracellular glutamate and glucose in awake, behaving rats and discuss how naturally occurring fluctuations in brain temperature affect these measurements. While this temperature contribution appears to be insignificant for glucose because its extracellular concentrations are large, it is a serious factor for electrochemical evaluations of glutamate, which is present in brain tissue at much lower levels, showing smaller phasic fluctuations. We further discuss experimental strategies for controlling the nonspecific chemical and physical contributions to electrochemical currents detected by enzyme-based biosensors to provide greater selectivity and reliability of neurochemical measurements in behaving animals.
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Affiliation(s)
- Eugene A. Kiyatkin
- In-Vivo Electrophysiology Unit, Behavioral Neuroscience
Branch, National Institute on Drug Abuse − Intramural Research
Program, National Institutes of Health,
DHHS, 333 Cassell Drive, Baltimore, Maryland 21224, United States
| | - Ken T. Wakabayashi
- In-Vivo Electrophysiology Unit, Behavioral Neuroscience
Branch, National Institute on Drug Abuse − Intramural Research
Program, National Institutes of Health,
DHHS, 333 Cassell Drive, Baltimore, Maryland 21224, United States
| | - Magalie Lenoir
- In-Vivo Electrophysiology Unit, Behavioral Neuroscience
Branch, National Institute on Drug Abuse − Intramural Research
Program, National Institutes of Health,
DHHS, 333 Cassell Drive, Baltimore, Maryland 21224, United States
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Ostojić Z, Ilić T, Vesković S, Andjus P. GABAB receptors as a common target for hypothermia and spike and wave seizures: Intersecting mechanisms of thermoregulation and absence epilepsy. Neuroscience 2013; 238:39-58. [DOI: 10.1016/j.neuroscience.2013.01.072] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Revised: 01/29/2013] [Accepted: 01/29/2013] [Indexed: 02/01/2023]
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Darlix A, Mathey G, Monin ML, Sauvée M, Braun M, Schaff JL, Debouverie M. [Hypothalamic involvement in multiple sclerosis]. Rev Neurol (Paris) 2011; 168:434-43. [PMID: 22136879 DOI: 10.1016/j.neurol.2011.09.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Revised: 09/24/2011] [Accepted: 09/29/2011] [Indexed: 01/26/2023]
Abstract
Hypothalamic involvement is a rare condition in patients with multiple sclerosis (MS). We report two patients with a long history of MS who presented with severe acute hypothermia with associated thrombocytopenia and elevated transaminase levels. Several cases of hypothermia or hyperthermia in patients with MS have been reported in the literature. They could be linked with hypothalamic lesions, in particular in the pre-optic area. However, other anatomical locations seem to be involved in thermoregulation and can be affected by MS. Besides, some cases of syndrome of inappropriate antidiuretic hormone secretion have been reported in patients with MS. Finally, some sleep disorders, particularly hypersomnia or narcolepsy, could be related to hypothalamic lesions, through the fall in hypocretin-1 in the cerebrospinal fluid. Hypocretin-1 is a neuropeptide that is secreted by some hypothalamic cells. It plays a role in the sleep-awake rhythm. We report one patient with narcolepsy and cataplexy before the first symptoms of MS appeared. Hypothalamic signs are rare in MS. However, several series of autopsies have shown a high frequency of demyelinating lesions in the hypothalamic area. Among these lesions, the proportion of active lesions seems elevated. Yet only few of them have a clinical or biological translation such as thermoregulation dysfunction, sleep disorders or natremia abnormalities. Thus, it seems unlikely that inflammatory hypothalamic lesions alone, even when bilateral, could be the explanation of these signs. A sufficient number of inflammatory demyelinating lesions, which we can observe in patients with a long history of MS and an already severe disability, is probably necessary to develop such a rare symptomatology. Hypothalamic signs might be a factor of poor prognosis for the disease course and progression of the disability.
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Affiliation(s)
- A Darlix
- Service de neurologie, hôpital Central, CHU de Nancy, 29 avenue du Maréchal-de-Lattre-de-Tassigny, Nancy cedex, France.
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Everaerts W, Nilius B, Owsianik G. The vanilloid transient receptor potential channel TRPV4: from structure to disease. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2009; 103:2-17. [PMID: 19835908 DOI: 10.1016/j.pbiomolbio.2009.10.002] [Citation(s) in RCA: 214] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2009] [Accepted: 10/07/2009] [Indexed: 12/19/2022]
Abstract
The Transient Receptor Potential Vanilloid 4 channel, TRPV4, is a Ca(2+) and Mg(2+) permeable non-selective cation channel involved in many different cellular functions. It is activated by a variety of physical and chemical stimuli, including heat, mechano-stimuli, endogenous substances such as arachidonic acid and its cytochrome P450-derived metabolites (epoxyeicosatrienoic acids), endocannabinoids (anandamide and 2-arachidonoylglycerol), as well as synthetic alpha-phorbol derivatives. Recently, TRPV4 has been characterized as an important player modulating osteoclast differentiation in bone remodelling and as a urothelial mechanosensor that controls normal voiding. Several TRPV4 gain-of-function mutations are shown to cause autosomal-dominant bone dysplasias such as brachyolmia and Koszlowski disease. In this review we comprehensively describe the structural, biophysical and (patho)physiological properties of the TRPV4 channel and we summarize the current knowledge about the role of TRPV4 in the pathogenesis of several diseases.
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Affiliation(s)
- Wouter Everaerts
- Department of Molecular Cell Biology, Laboratory Ion Channel Research, Campus Gasthuisberg, KULeuven, Herestraat 49, bus 802, B-3000 Leuven, Belgium
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Green BG, Akirav C. Individual differences in temperature perception: Evidence of common processing of sensation intensity of warmth and cold. Somatosens Mot Res 2009; 24:71-84. [PMID: 17558924 DOI: 10.1080/08990220701388117] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The longstanding question of whether temperature is sensed via separate sensory systems for warmth and cold was investigated by measuring individual differences in perception of nonpainful heating and cooling. Sixty-two subjects gave separate ratings of the intensity of thermal sensations (warmth, cold) and nociceptive sensations (burning/stinging/pricking) produced by cooling (29 degrees C) or heating (37 degrees C) local regions of the forearm. Stimuli were delivered via a 4 x 4 array of 8 mm x 8 mm Peltier thermoelectric modules that enabled test temperatures to be presented sequentially to individual modules or simultaneously to the full array. Stimulation of the full array showed that perception of warmth and cold were highly correlated (Pearson r = 0.83, p < 0.05). Ratings of nonpainful nociceptive sensations produced by the two temperatures were also correlated, but to a lesser degree (r = 0.44), and the associations between nociceptive and thermal sensations (r = 0.35 and 0.22 for 37 and 29 degrees C, respectively) were not significant after correction for multiple statistical tests. Intensity ratings for individual modules indicated that the number of responsive sites out of 16 was a poor predictor of temperature sensations but a significant predictor of nociceptive sensations. The very high correlation between ratings of thermal sensations conflicts with the classical view that warmth and cold are mediated by separate thermal modalities and implies that warm-sensitive and cold-sensitive spinothalamic pathways converge and undergo joint modulation in the central nervous system. Integration of thermal stimulation from the skin and body core within the thermoregulatory system is suggested as the possible source of this convergence.
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Affiliation(s)
- Barry G Green
- The John B. Pierce Laboratory, Yale University School of Medicine, New Haven, CT 06519, USA.
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Dundar NO, Boz A, Duman O, Aydin F, Haspolat S. Spontaneous periodic hypothermia and hyperhidrosis. Pediatr Neurol 2008; 39:438-40. [PMID: 19027594 DOI: 10.1016/j.pediatrneurol.2008.08.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2007] [Revised: 07/14/2008] [Accepted: 08/13/2008] [Indexed: 11/16/2022]
Abstract
We present a patient diagnosed with Shapiro syndrome without corpus callosum agenesis. A 4-year-old-girl was admitted to the hospital with complaints of sweating, cooling, and drowsiness that continued during the last week of her admission. Attacks occurred almost daily, and lasted for about 1 hour. All laboratory findings, as well as Holter and echocardiography results, were normal. Cranial magnetic resonance imaging demonstrated an intact corpus callosum, and electroencephalography obtained during an attack revealed normal findings. However, technetium 99m-labeled hexamethylpropylene amine oxime brain single-photon emission computed tomography indicated increased perfusion in the right thalamus, basal ganglia, and inferior frontal areas during a hypothermic period. Although oxcarbazepine reduced the frequency of attacks, they were not halted completely. The patient responded better to carbamazepine.
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Affiliation(s)
- Nihal Olgac Dundar
- Department of Child Neurology, Faculty of Medicine, Akdeniz University, Antalya, Turkey
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Kiyatkin EA. Brain temperature fluctuations during physiological and pathological conditions. Eur J Appl Physiol 2007; 101:3-17. [PMID: 17429680 DOI: 10.1007/s00421-007-0450-7] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/16/2007] [Indexed: 12/15/2022]
Abstract
This review discusses brain temperature as a physiological parameter, which is determined primarily by neural metabolism, regulated by cerebral blood flow, and affected by various environmental factors and drugs. First, we consider normal fluctuations in brain temperature that are induced by salient environmental stimuli and occur during motivated behavior at stable normothermic conditions. Second, we analyze changes in brain temperature induced by various drugs that affect brain and body metabolism and heat dissipation. Third, we consider how these physiological and drug-induced changes in brain temperature are modulated by environmental conditions that diminish heat dissipation. Our focus is psychomotor stimulant drugs and brain hyperthermia as a factor inducing or potentiating neurotoxicity. Finally, we discuss how brain temperature is regulated, what changes in brain temperature reflect, and how these changes may affect neural functions under normal and pathological conditions. Although most discussed data were obtained in animals and several important aspects of brain temperature regulation in humans remain unknown, our focus is on the relevance of these data for human physiology and pathology.
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Affiliation(s)
- Eugene A Kiyatkin
- Behavioral Neuroscience Branch, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, DHHS, Baltimore, MD 21224, USA.
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Abstract
While brain temperature is usually considered a stable, tightly regulated parameter, recent animal research revealed relatively large and rapid brain temperature fluctuations (approximately 3 degrees C) during various forms of naturally occurring physiological and behavioral activities. This work demonstrates that physiological brain hyperthermia has an intra-brain origin, resulting from enhanced neural metabolism and increased intra-brain heat production, and discusses its possible mechanisms and functional consequences. This work also shows that brain hyperthermia may also be induced by various drugs of abuse. While each individual drug (i.e., heroin, cocaine, meth-amphetamine, MDMA) has its own, dose-dependent effects on brain and body temperatures, these effects are strongly modulated by the individual's activity state and environmental conditions, showing dramatic alterations during the development of drug-taking behavior. While brain temperatures may also increase due to environmental overheating and diminished heat dissipation from the brain, adverse environmental conditions and physiological activation strongly potentiate thermal effects of psychomotor stimulant drugs, resulting in dangerous brain overheating. Since hyperthermia exacerbates drug-induced toxicity and is destructive to neural cells and brain functions, use of these drugs under conditions that restrict heat loss may pose a significant health risk, resulting in both acute life-threatening complications and chronic destructive CNS changes. We argue that brain temperature is an important physiological parameter, affecting various neural functions, and show the potential of brain temperature monitoring for studying alterations in metabolic neural activity under physiological and pathological conditions. Finally, we discuss brain temperature as a factor affecting various neuronal and neurochemical evaluations made in different animal preparations (in vitro slices, general anesthesia, awake, freely moving conditions) and consider a possible contribution of temperature fluctuations to behavior-related and drug-induced alterations in neuronal and neurochemical parameters.
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Affiliation(s)
- Eugene A Kiyatkin
- Cellular Neurobiology Branch, National Institute on Drug Abuse - Intramural Research Program, National Institutes of Health, DHHS, Baltimore, MD 21224, USA.
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Linker RA, Mohr A, Cepek L, Gold R, Prange H. Core hypothermia in multiple sclerosis: case report with magnetic resonance imaging localization of a thalamic lesion. Mult Scler 2006; 12:112-5. [PMID: 16459729 DOI: 10.1191/135248506ms1268cr] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Hypothermia is a rare condition in multiple sclerosis (MS). We report on a patient with a long-standing secondary progressive MS and six episodes of recurring hypothermia down to 29.9 degrees C with associated hypotension, bradycardia, coagulopathy and electrolyte dysequilibrium. Magnetic resonance imaging (MRI) demonstrated severe involvement of the corpus callosum with an associated lesion in the right posterior thalamus. These findings may link hypothermia in MS with callosal and associated thalamic pathology to Shapiro's syndrome, where agenesis of the corpus callosum and associated abnormalities are related to episodic spontaneous hypothermia. In MS, hypothermic episodes may be triggered by preceding infections, as shown in the present case.
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Affiliation(s)
- R A Linker
- Department of Neurology, Bereich Humanmedizin, Georg-August-Universität Göttingen, Robert-Koch-Str. 40, D-37099 Goettingen, Germany.
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Kiyatkin EA. Brain hyperthermia as physiological and pathological phenomena. ACTA ACUST UNITED AC 2006; 50:27-56. [PMID: 15890410 DOI: 10.1016/j.brainresrev.2005.04.001] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2004] [Revised: 01/04/2005] [Accepted: 04/05/2005] [Indexed: 12/18/2022]
Abstract
Although brain metabolism consumes high amounts of energy and is accompanied by intense heat production, brain temperature is usually considered a stable, tightly "regulated" homeostatic parameter. Current research, however, revealed relatively large and rapid brain temperature fluctuations (3-4 degrees C) in animals during various normal, physiological, and behavioral activities at stable ambient temperatures. This review discusses these data and demonstrates that physiological brain hyperthermia has an intra-brain origin, resulting from enhanced neural metabolism and increased intra-brain heat production. Therefore, brain temperature is an important physiological parameter that both reflects alterations in metabolic neural activity and affects various neural functions. This work also shows that brain hyperthermia may be induced by various drugs of abuse that cause metabolic brain activation and impair heat dissipation. While individual drugs (i.e., heroin, cocaine, methamphetamine, MDMA) have specific, dose-dependent effects on brain and body temperatures, these effects are strongly modulated by an individual's activity state and environmental conditions, and change dramatically during the development of drug self-administration. Thus, brain thermorecording may provide new information on the central effects of various addictive drugs, drug-activity-environment interactions in mediating drugs' adverse effects, and alterations in metabolic neural activity associated with the development of drug-seeking and drug-taking behavior. While ambient temperatures and impairment of heat dissipation may also affect brain temperature, these environmental conditions strongly potentiate thermal effects of psychomotor stimulant drugs, resulting in pathological brain overheating. Since hyperthermia exacerbates drug-induced toxicity and is destructive to neural cells and brain functions, use of these drugs under activated conditions that restrict heat loss may pose a significant health risk, resulting in both acute life-threatening complications and chronic destructive CNS changes.
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Affiliation(s)
- Eugene A Kiyatkin
- Cellular Neurobiology Branch, National Institute on Drug Abuse-Intramural Research Program, National Institutes of Health, DHHS, 5500 Nathan Shock, Baltimore, MD 21224, USA.
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Guatteo E, Chung KKH, Bowala TK, Bernardi G, Mercuri NB, Lipski J. Temperature Sensitivity of Dopaminergic Neurons of the Substantia Nigra Pars Compacta: Involvement of Transient Receptor Potential Channels. J Neurophysiol 2005; 94:3069-80. [PMID: 16014800 DOI: 10.1152/jn.00066.2005] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Changes in temperature of up to several degrees have been reported in different brain regions during various behaviors or in response to environmental stimuli. We investigated temperature sensitivity of dopaminergic neurons of the rat substantia nigra pars compacta (SNc), an area important for motor and emotional control, using a combination of electrophysiological techniques, microfluorometry, and RT-PCR in brain slices. Spontaneous neuron firing, cell membrane potential/currents, and intracellular Ca2+level ([Ca2+]i) were measured during cooling by ≤10° and warming by ≤5° from 34°C. Cooling evoked slowing of firing, cell membrane hyperpolarization, increase in cell input resistance, an outward current under voltage clamp, and a decrease of [Ca2+]i. Warming induced an increase in firing frequency, a decrease in input resistance, an inward current, and a rise in [Ca2+]i. The cooling-induced current, which reversed in polarity between −5 and −17 mV, was dependent on extracellular Na+. Cooling-induced whole cell currents and changes in [Ca2+]iwere attenuated by 79% in the presence of 2-aminoethoxydiphenylborane (2-APB; 200 μM), and the outward current was reduced by 20% with ruthenium red (100 μM). RT-PCR conducted with tissue punches containing the SNc revealed mRNA expression for TRPV3 and TRPV4 channels, known to be activated in expression systems by temperature changes within the physiological range. 2-APB, a TRPV3 modulator, increased baseline [Ca2+]i, whereas 4αPDD, a TRPV4 agonist, increased spontaneous firing in 7 of 14 neurons tested. We conclude that temperature-gated TRPV3 and TRPV4 cationic channels are expressed in nigral dopaminergic neurons and are constitutively active in brain slices at near physiological temperatures, where they affect the excitability and calcium homeostasis of these neurons.
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Nilius B, Vriens J, Prenen J, Droogmans G, Voets T. TRPV4 calcium entry channel: a paradigm for gating diversity. Am J Physiol Cell Physiol 2004; 286:C195-205. [PMID: 14707014 DOI: 10.1152/ajpcell.00365.2003] [Citation(s) in RCA: 350] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The vanilloid receptor-1 (VR1, now TRPV1) was the founding member of a subgroup of cation channels within the TRP family. The TRPV subgroup contains six mammalian members, which all function as Ca2+ entry channels gated by a variety of physical and chemical stimuli. TRPV4, which displays 45% sequence identity with TRPV1, is characterized by a surprising gating promiscuity: it is activated by hypotonic cell swelling, heat, synthetic 4alpha-phorbols, and several endogenous substances including arachidonic acid (AA), the endocannabinoids anandamide and 2-AG, and cytochrome P-450 metabolites of AA, such as epoxyeicosatrienoic acids. This review summarizes data on TRPV4 as a paradigm of gating diversity in this subfamily of Ca2+ entry channels.
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Affiliation(s)
- Bernd Nilius
- Laboratorium voor Fysiologie, KU Leuven, Campus Gasthuisberg, 3000 Leuven, Belgium.
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Patapoutian A, Peier AM, Story GM, Viswanath V. ThermoTRP channels and beyond: mechanisms of temperature sensation. Nat Rev Neurosci 2003; 4:529-39. [PMID: 12838328 DOI: 10.1038/nrn1141] [Citation(s) in RCA: 543] [Impact Index Per Article: 25.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Ardem Patapoutian
- Department of Cell Biology, The Scripps Research Institute, La Jolla, California 92037, USA.
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Abstract
Spontaneous activity originating in the injured nerve or the dorsal root ganglion (DRG) has been implicated in the development and maintenance of neuropathic pain. The inherent characteristics of spontaneous activity and the causal factors that modulate its firing pattern and frequency are not fully understood. We attempted to assess the thermosensitivity of spontaneous activity in dorsal root ganglion (DRG) neurons in normal rats and in rats with chronic compression of the DRG (CCD) in an in vitro nerve-DRG preparation. Extracellular, dorsal root recording from 66 spontaneously active CCD Abeta fibers indicate that: (1) decreasing bath temperature from 37 to 36-26 degrees C significantly decreased the firing rate (FR) in 85% (56/66) of fibers tested, of which 19 fibers (34%) responded to temperature change at physiological range (36-37 degrees C), whereas the remaining fibers responded at lower temperature levels (26-36 degrees C); (2) cooling of the DRG increased the FR in 12% (8/66) of fibers tested; (3) similarly, the firing rate of 21/26 spontaneously active Abeta fibers from normal rats was decreased following temperature decrease; (4) intracellular recordings from 38 normal neurons revealed that cooling the DRG significantly increased the action potential (AP) threshold, AP duration, AP amplitude and afterhyperpolarization (AHP) duration, but decreased AHP amplitude, maximal depolarizing and repolarizing rates. There was no significant change in the rheobase currents or the resting membrane potential. The present study indicates that large sensory neurons with myelinated axons are temperature dependent. It also suggests that maintenance of a stable temperature is critical for reliable characterization of spontaneous activity of sensory neurons.
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Affiliation(s)
- Huiqing Li
- Department of Anesthesiology, Slot 515, University of Arkansas for Medical Sciences, 4301 West Markham Street, Little Rock, AR 72205, USA
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Kuznetsov IE, Kazakov VN. Integration of thermal and osmotic afferent signals in the preoptic/anterior hypothalamic neurons. Neuroscience 2000; 99:363-71. [PMID: 10938442 DOI: 10.1016/s0306-4522(00)00184-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Our in vivo experiments were aimed at studying afferent links of the preoptic/anterior hypothalamus system, which integrates thermal and osmotic homeostasis. Special attention was paid to using stimulation intensities within the normal physiological range. The experiments were carried out on adult cats anesthetized with ketamine (25mg/kg) and inhalation of nitrous oxide (75 vol.%). Short-term shifts in the osmotic pressure within the cerebral vasculature were induced by infusions of 200-500 microl 3.0% or 0.2% NaCl solutions into the homolateral a. carotis (hyper- and hypoosmotic stimulations, respectively). Thermal stimulation was provided by local heating or cooling of the contralateral forelimb pad skin (+/-7.0 degrees C range). Reactions of preoptic/anterior hypothalamus neurons were classified into four types: monophasic activation, monophasic inhibition, and biphasic responses including excitation followed by inhibition or primary inhibition followed by activation. Monophasic activation was a very common occurrence among preoptic/anterior hypothalamus neuronal reactions. The responsiveness of thermosensitive preoptic/anterior hypothalamus neurons to hyperosmotic stimulation turned to be noticeably higher than that to hypoosmotic stimulation. Practically equal proportions of warm- and cold-sensitive neurons demonstrated changes in the firing activity resulting from intracarotid infusions of 3.0% NaCl solution. Infusions of 0.2% NaCl solution induced firing rate modifications in 26% (12/46) of warm-sensitive and in 32% (18/39) of cold-sensitive neurons. Cold-sensitive neurons displayed a higher sensitivity to a short-term osmotic pressure elevation in the cerebral vasculature (63%, 33/52) than warm-sensitive neurons did (43%, 22/52, P<0.05). In our study, a maximum similarity in the response types was observed when hyperosmotic infusion and skin cooling were applied, while a maximum disagreement was found when hyperosmotic stimulations were combined with skin heating. There is no doubt that preoptic/anterior hypothalamus neurons play a crucial role in the maintenance of body temperature. Several studies have also shown that osmoregulation can be affected by shifts in peripheral and hypthalmic temperatures. Information on the neurol mechanisms of interactions between the thermo- and osmoregulatory circuits in the hypothalamus remains limited. We discuss the obtained data considering the "set-point theory" of thermal hameostasis maintenance.
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Affiliation(s)
- I E Kuznetsov
- Department of Physiology, Donetsk State Medical University, Illych Avenue, 16, 83003, Donetsk, Ukraine.
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Van Someren EJ. More than a marker: interaction between the circadian regulation of temperature and sleep, age-related changes, and treatment possibilities. Chronobiol Int 2000; 17:313-54. [PMID: 10841209 DOI: 10.1081/cbi-100101050] [Citation(s) in RCA: 191] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The neurobiological mechanisms of both sleep and circadian regulation have been unraveled partly in the last decades. A network of brain structures, rather than a single locus, is involved in arousal state regulation, whereas the suprachiasmatic nucleus (SCN) has been recognized as a key structure for the regulation of circadian rhythms. Although most models of sleep regulation include a circadian component, the actual mechanism by which the circadian timing system promotes--in addition to homeostatic pressure--transitions between sleep and wakefulness remains to be elucidated. Little more can be stated presently than a probable involvement of neuronal projections and neurohumoral factors originating in the SCN. This paper reviews the relation among body temperature, arousal state, and the circadian timing system and proposes that the circadian temperature rhythm provides an additional signaling pathway for the circadian modulation of sleep and wakefulness. A review of the literature shows that increased brain temperature is associated with a type of neuronal activation typical of sleep in some structures (hypothalamus, basal forebrain), but typical of wakefulness in others (midbrain reticular formation, thalamus). Not only local temperature, but also skin temperature are related to the activation type in these structures. Warming of the skin is associated with an activation type typical of sleep in the midbrain reticular formation, hypothalamus, and cerebral cortex (CC). The decreasing part of the circadian rhythm in core temperature is mainly determined by heat loss from the skin of the extremities, which is associated with strongly increased skin temperature. As such, alterations in core and skin temperature over the day could modulate the neuronal activation state or "preparedness for sleep" in arousal-related brain structures. Body temperature may thus provide a third signaling pathway, in addition to synaptic and neurohumoral pathways, for the circadian modulation of sleep. A proposed model for the effects of body temperature on sleep appears to fit the available data better than previous hypotheses on the relation between temperature and sleep. Moreover, when the effects of age-related thermoregulatory alterations are introduced into the model, it provides an adequate description of age-related changes in sleep, including shallow sleep and awakening closer to the nocturnal core temperature minimum. Finally, the model indicates that appropriately timed direct (passive heating) or indirect (bright light, melatonin, physical activity) manipulation of the nocturnal profile of skin and core temperature may be beneficial to disturbed sleep in the elderly. Although such procedures could be viewed by researchers as merely masking a marker for the endogenous rhythm, they may in fact be crucial for sleep improvement in elderly subjects.
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Bethea CL, Pecins-Thompson M, Schutzer WE, Gundlah C, Lu ZN. Ovarian steroids and serotonin neural function. Mol Neurobiol 1998; 18:87-123. [PMID: 10065876 DOI: 10.1007/bf02914268] [Citation(s) in RCA: 122] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The serotonin neural system originates from ten nuclei in the mid- and hindbrain regions. The cells of the rostral nuclei project to almost every area of the forebrain, including the hypothalamus, limbic regions, basal ganglia, thalamic nuclei, and cortex. The caudal nuclei project to the spinal cord and interact with numerous autonomic and sensory systems. This article reviews much of the available literature from basic research and relevant clinical research that indicates that ovarian steroid hormones, estrogens and progestins, affect the function of the serotonin neural system. Experimental results in nonhuman primates from this laboratory are contrasted with studies in rodents and humans. The sites of action of ovarian hormones on the serotonin neural system include effects within serotonin neurons as well as effects on serotonin afferent neurons and serotonin target neurons. Therefore, information on estrogen and progestin receptor-containing neurons was synthesized with information on serotonin afferent and efferent circuits. The ability of estrogens and progestins to alter the function of the serotonin neural system at various levels provides a cellular mechanism whereby ovarian hormones can impact mood, cognition, pain, and numerous other autonomic functions.
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Affiliation(s)
- C L Bethea
- Oregon Regional Primate Research Center, Beaverton 97006, USA
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Ostojić ZS, Ruzdijić S, Car M, Rakić L, Veskov R. The connection between absence-like seizures and hypothermia induced by penicillin: possible implication on other animal models of petit mal epilepsy. Brain Res 1997; 777:86-94. [PMID: 9449416 DOI: 10.1016/s0006-8993(97)01007-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
In this study we investigated the relationship between penicillin-induced hypothermia and petit mal epilepsy induced by this proconvulsant antibiotic. In order to find a possible dose-dependent relationship, we used two doses: 1500.000 and 1000.000 U/kg b.wt., both known as being sufficient to induce absence-like attacks with subsequent spike and wave discharges (SWD) in electrocorticogram (ECoG). Because of experimental data suggesting penicillin binding to benzodiazepine receptor recognition site, we also studied penicillin-induced changes in body temperature after diazepam pretreatment. Results of this study clearly show that penicillin in doses known to induce petit mal-like epilepsy concomitantly induces statistically significant dose-dependent decrease in body temperature. Pretreatment with diazepam completely prevents both penicillin-induced hypothermia and SWDs. On the other hand, both the diazepam and mixed diazepam + penicillin treatments did not significantly alter body temperature. These results suggest, however, that at least some of the penicillin effects described could be assigned to its binding to the benzodiazepine receptor recognition site at GABA(A) ionophore. This may have an important clinical implication because the inhibitory action of penicillin at the benzodiazepine receptor recognition site could account for the mechanism of penicillin-induced unspecific encephalopathies in humans. The relationship between petit mal epilepsy and hypothermia sheds new light on the action mechanisms of penicillin-induced absence seizures.
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Affiliation(s)
- Z S Ostojić
- Institute for Biological Research, Department for Neurobiology and Immunology, University of Belgrade, Yugoslavia
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