301
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Radler ME, Hale MW, Kent S. Calorie restriction attenuates lipopolysaccharide (LPS)-induced microglial activation in discrete regions of the hypothalamus and the subfornical organ. Brain Behav Immun 2014; 38:13-24. [PMID: 24291211 DOI: 10.1016/j.bbi.2013.11.014] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Revised: 11/06/2013] [Accepted: 11/20/2013] [Indexed: 12/11/2022] Open
Abstract
Calorie restriction (CR) has been shown to increase longevity and elicit many health promoting benefits including delaying immunosenescence and attenuating neurodegeneration in animal models of Alzheimer's disease and Parkinson's disease. CR also suppresses microglial activation following cortical injury and aging. We previously demonstrated that CR attenuates lipopolysaccharide (LPS)-induced fever and shifts hypothalamic signaling pathways to an anti-inflammatory bias; however, the effects of CR on LPS-induced microglial activation remain largely unexplored. The current study investigated regional changes in LPS-induced microglial activation in mice exposed to 50% CR for 28days. Immunohistochemistry was conducted to examine changes in ionized calcium-binding adapter molecule-1 (Iba1), a protein constitutively expressed by microglia, in a total of 27 brain regions involved in immunity, stress, and/or thermoregulation. Exposure to CR attenuated LPS-induced fever, and LPS-induced microglial activation in a subset of regions: the arcuate nucleus (ARC) and ventromedial nucleus of the hypothalamus (VMH) and the subfornical organ (SFO). Microglial activation in the ARC and VMH was positively correlated with body temperature. These data suggest that CR exerts effects on regionally specific populations of microglia; particularly, in appetite-sensing regions of the hypothalamus, and/or regions lacking a complete blood brain barrier, possibly through altered pro- and anti-inflammatory signaling in these regions.
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Affiliation(s)
- Morgan E Radler
- School of Psychological Science, La Trobe University, Melbourne, VIC, Australia
| | - Matthew W Hale
- School of Psychological Science, La Trobe University, Melbourne, VIC, Australia
| | - Stephen Kent
- School of Psychological Science, La Trobe University, Melbourne, VIC, Australia.
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302
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Zaretsky DV, Zaretskaia MV, Durant PJ, Rusyniak DE. Inhibition of the dorsomedial hypothalamus, but not the medullary raphe pallidus, decreases hyperthermia and mortality from MDMA given in a warm environment. Pharmacol Res Perspect 2014; 2:e00031. [PMID: 24765530 PMCID: PMC3994179 DOI: 10.1002/prp2.31] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The central mechanisms through which MDMA mediates life-threatening hyperthermia when taken in a warm environment are not well described. It is assumed that MDMA alters normal thermoregulatory circuits resulting in increased heat production through interscapular brown adipose tissue (iBAT) and decreased heat dissipation through cutaneous vasoconstriction. We studied the role of the dorsomedial hypothalamus (DMH) and medullary raphe pallidus (mRPa) in mediating iBAT, tail blood flow, and locomotor effects produced by MDMA. Rats were instrumented with guide cannulas targeting either the DMH or the mRPa-brain regions involved in regulating iBAT and cutaneous vascular beds. In all animals, core temperature and locomotion were recorded with surgically implanted telemetric transmitters; and additionally either iBAT temperature (via telemetric transmitter) or tail artery blood flow (via tail artery Doppler cuff) were also recorded. Animals were placed in an environmental chamber at 32°C and microinjected with either control or the GABA agonist muscimol (80pmol) followed by an intravenous injection of saline or MDMA (7.5 mg kg-1). To prevent undue suffering, a core temperature of 41°C was chosen as the surrogate marker of mortality. Inhibition of the DMH, but not the mRPa, prevented mortality and attenuated hyperthermia and locomotion. Inhibition of either the DMH or the mRPa did not affect iBAT temperature increases or tail blood flow decreases. While MDMA increases iBAT thermogenesis and decreases heat dissipation through cutaneous vasoconstriction, thermoregulatory brain regions known to mediate these effects are not involved. Rather, the finding that inhibiting the DMH decreases both locomotion and body temperature suggests that locomotion may be a key central contributor to MDMA-evoked hyperthermia.
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Affiliation(s)
- Dmitry V Zaretsky
- Department of Emergency Medicine, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Maria V Zaretskaia
- Department of Emergency Medicine, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Pamela J Durant
- Department of Emergency Medicine, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Daniel E Rusyniak
- Department of Emergency Medicine, Indiana University School of Medicine, Indianapolis, Indiana, USA ; Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, Indiana, USA
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303
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Tomita M, Katsuyama H, Watanabe Y, Shibaike Y, Yoshinari H, Tee JW, Iwachidou N, Miyamoto O. c-Fos immunoreactivity of neural cells in intoxication due to high-dose methamphetamine. J Toxicol Sci 2014; 38:671-8. [PMID: 24025783 DOI: 10.2131/jts.38.671] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Methamphetamine (METH) is a powerful and toxic psychostimulant that is abused worldwide. Although many studies of its toxic functions have been done on animals and humans, the mechanism is still poorly understood. In addition, the doses of METH examined have often been low. Here, we investigated the effects of intoxication due to administration of 20 mg/kg METH on neuronal activity. The mice showed hyperthermia and stereotyped behavior during 60 min after injection. We examined plasma stress hormone levels, which indicated that exposure to METH stimulated the hypothalamic-pituitary-adrenal (HPA) axis and caused release of stress hormones soon after injection. The maximum levels of adrenocorticotropic hormone and corticosterone occurred 10 and 60 min, respectively, after injection. We examined c-Fos protein in 16 different brain regions at 60 min post injection to identify potential brain regions subject to the stimulant effect. Nine regions, including the anterior hypothalamic area, medial preoptic area, lateral hypothalamic area, paraventricular thalamic nucleus, lateral anterior hypothalamic nucleus, lateral septum, striatum, nucleus accumbens, and amygdala, showed a significant increase in c-Fos expression, while the other seven regions did not. These results indicate that responsive neurons in the regions containing c-Fos immunoreactivity (Fos-IR) may undergo cellular reaction to high-dose METH administration. The present study provides support for a relationship among hyperthermia, the HPA axis and neuronal activities in limited brain regions on exposure to 20 mg/kg METH.
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304
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Mohammed M, Ootsuka Y, Blessing W. Brown adipose tissue thermogenesis contributes to emotional hyperthermia in a resident rat suddenly confronted with an intruder rat. Am J Physiol Regul Integr Comp Physiol 2014; 306:R394-400. [PMID: 24452545 PMCID: PMC3949111 DOI: 10.1152/ajpregu.00475.2013] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Body temperature increases when individuals experience salient, emotionally significant events. There is controversy concerning the contribution of nonshivering thermogenesis in brown adipose tissue (BAT) to emotional hyperthermia. In the present study we compared BAT, core body, and brain temperature, and tail blood flow, simultaneously measured, to determine whether BAT thermogenesis contributes to emotional hyperthermia in a resident Sprague-Dawley rat when an intruder rat, either freely-moving or confined to a small cage, is suddenly introduced into the cage of the resident rat for 30 min. Introduction of the intruder rat promptly increased BAT, body, and brain temperatures in the resident rat. For the caged intruder these temperature increases were 1.4 ± 0.2, 0.8 ± 0.1, 1.0 ± 0.1°C, respectively, with the increase in BAT temperature being significantly greater (P < 0.01) than the increases in body and brain. The initial 5-min slope of the BAT temperature record (0.18 ± 0.02°C/min) was significantly greater (P < 0.01) than the corresponding value for body (0.10 ± 0.01°C/min) and brain (0.09 ± 0.02°C/min). Tail artery pulse amplitude fell acutely when the intruder rat was introduced, possibly contributing to the increases in body and brain temperature. Prior blockade of β3 adrenoceptors (SR59230A 10 mg/kg ip) significantly reduced the amplitude of each temperature increase. Intruder-evoked increases in BAT temperature were similar in resident rats maintained at 11°C for 3 days. In the caged intruder situation there is no bodily contact between the rats, so the stimulus is psychological rather than physical. Our study thus demonstrates that BAT thermogenesis contributes to increases in body and brain temperature occurring during emotional hyperthermia.
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Affiliation(s)
- Mazher Mohammed
- Department of Human Physiology, Flinders University, Adelaide, South Australia, Australia
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305
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Abstract
Disorders of elevated body temperature may be classified as either fever or hyperthermia. Fever is caused by a pyrogen-mediated upward adjustment of the hypothalamic thermostat; hyperthermia results from a loss of physiologic control of temperature regulation. Fever in the ICU can be due to infectious or noninfectious causes. The initial approach to a febrile, critically ill patient should involve a thoughtful review of the clinical data to elicit the likely source of fever prior to the ordering of cultures, imaging studies, and broad-spectrum antibiotics. Both high fever and prolonged fever have been associated with increased mortality; however, a causal role for fever as a mediator of adverse outcomes during non-neurologic critical illness has not been established. Outside the realm of acute brain injury, the practice of treating fever remains controversial. To generate high-quality, evidence-based guidelines for the management of fever, large, prospective, multicenter trials are needed.
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Affiliation(s)
- Tayyab Rehman
- Section of Pulmonary & Critical Care Medicine, Department of Medicine, LSU Health Sciences Center, New Orleans, LA
| | - Bennett P deBoisblanc
- Section of Pulmonary & Critical Care Medicine, Department of Medicine, LSU Health Sciences Center, New Orleans, LA.
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306
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Hypoxia-induced hypothermia mediated by GABA in the rostral parapyramidal area of the medulla oblongata. Neuroscience 2014; 267:46-56. [PMID: 24607346 DOI: 10.1016/j.neuroscience.2014.02.035] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2013] [Revised: 02/04/2014] [Accepted: 02/22/2014] [Indexed: 11/20/2022]
Abstract
Hypoxia evokes a regulated decrease in the body core temperature (Tc) in a variety of animals. The neuronal mechanisms of this response include, at least in part, glutamatergic activation in the lateral preoptic area (LPO) of the hypothalamus. As the sympathetic premotor neurons in the medulla oblongata constitute a cardinal relay station in the descending neuronal pathway from the hypothalamus for thermoregulation, their inhibition can also be critically involved in the mechanisms of the hypoxia-induced hypothermia. Here, I examined the hypothesis that hypoxia-induced hypothermia is mediated by glutamate-responsive neurons in the LPO that activate GABAergic transmission in the rostral raphe pallidus (rRPa) and neighboring parapyramidal region (PPy) of the medulla oblongata in urethane-chloralose-anesthetized, neuromuscularly blocked, artificially ventilated rats. Unilateral microinjection of GABA (15nmol) into the rRPa and PPy regions elicited a prompt increase in tail skin temperature (Ts) and decreases in Tc, oxygen consumption rate (VO2), and heart rate. Next, when the GABAA receptor blocker bicuculline methiodide (bicuculline methiodide (BMI), 10pmol) alone was microinjected into the rRPa, it elicited unexpected contradictory responses: simultaneous increases in Ts, VO2 and heart rate and a decrease in Tc. Then, when BMI was microinjected bilaterally into the PPy, no direct effect on Ts was seen; and thermogenic and tachycardic responses were slight. However, pretreatment of the PPy with BMI, but not vehicle saline, greatly attenuated the hypothermic responses evoked by hypoxic (10%O2-90%N2, 5min) ventilation or bilateral microinjections of glutamate (5nmol, each side) into the LPO. The results suggest that hypoxia-induced hypothermia was mediated, at least in part, by the activation of GABAA receptors in the PPy.
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307
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Abstract
This review analyses whether skin temperature represents ambient temperature and serves as a feedforward signal for the thermoregulation system, or whether it is one of the body's temperatures and provides feedback. The body is covered mostly by hairy (non-glabrous) skin, which is typically insulated from the environment (with clothes in humans and with fur in non-human mammals). Thermal signals from hairy skin represent a temperature of the insulated superficial layer of the body and provide feedback to the thermoregulation system. It is explained that this feedback is auxiliary, both negative and positive, and that it reduces the system's response time and load error. Non-hairy (glabrous) skin covers specialized heat-exchange organs (e.g. the hand), which are also used to explore the environment. In thermoregulation, these organs are primarily effectors. Their main thermosensory-related role is to assess local temperatures of objects explored; these local temperatures are feedforward signals for various behaviours. Non-hairy skin also contributes to the feedback for thermoregulation, but this contribution is limited. Autonomic (physiological) thermoregulation does not use feedforward signals. Thermoregulatory behaviours use both feedback and feedforward signals. Implications of these principles to thermopharmacology, a new approach to achieving biological effects by blocking temperature signals with drugs, are discussed.
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Affiliation(s)
- A. A. Romanovsky
- Trauma Research Systemic Inflammation Laboratory (FeverLab) St. Joseph's Hospital and Medical Center Phoenix AZUSA
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308
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Morris NB, Bain AR, Cramer MN, Jay O. Evidence that transient changes in sudomotor output with cold and warm fluid ingestion are independently modulated by abdominal, but not oral thermoreceptors. J Appl Physiol (1985) 2014; 116:1088-95. [PMID: 24577060 DOI: 10.1152/japplphysiol.01059.2013] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Two studies were performed to 1) characterize changes in local sweat rate (LSR) following fluid ingestion of different temperatures during exercise, and 2) identify the potential location of thermoreceptors along the gastrointestinal tract that independently modify sudomotor activity. In study 1, 12 men cycled at 50% Vo2peak for 75 min while ingesting 3.2 ml/kg of 1.5°C, 37°C, or 50°C fluid 5 min before exercise; and after 15, 30, and 45-min of exercise. In study 2, 8 men cycled at 50% Vo2peak for 75 min while 3.2 ml/kg of 1.5°C or 50°C fluid was delivered directly into the stomach via a nasogastric tube (NG trials) or was mouth-swilled only (SW trials) after 15, 30, and 45 min of exercise. Rectal (Tre), aural canal (Tau), and mean skin temperature (Tsk); and LSR on the forehead, upper-back, and forearm were measured. In study 1, Tre, Tau, and Tsk were identical between trials, but after each ingestion, LSR was significantly suppressed at all sites with 1.5°C fluid and was elevated with 50°C fluid compared with 37°C fluid (P < 0.001). The peak difference in mean LSR between 1.5°C and 50°C fluid after ingestion was 0.29 ± 0.06 mg·min(-1)·cm(-2). In study 2, LSR was similar between 1.5°C and 50°C fluids with SW trials (P = 0.738), but lower at all sites with 1.5°C fluid in NG trials (P < 0.001) despite no concurrent differences in Tre, Tau, and Tsk. These data demonstrate that 1) LSR is transiently altered by cold and warm fluid ingestion despite similar core and skin temperatures; and 2) thermoreceptors that independently and acutely modulate sudomotor output during fluid ingestion probably reside within the abdominal area, but not the mouth.
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Affiliation(s)
- Nathan B Morris
- Thermal Ergonomics Laboratory, School of Human Kinetics, University of Ottawa, Ottawa, Ontario, Canada
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309
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Faiz HR, Rahimzadeh P, Visnjevac O, Behzadi B, Ghodraty MR, Nader ND. Intravenous acetaminophen is superior to ketamine for postoperative pain after abdominal hysterectomy: results of a prospective, randomized, double-blind, multicenter clinical trial. J Pain Res 2014; 7:65-70. [PMID: 24465135 PMCID: PMC3900330 DOI: 10.2147/jpr.s53234] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND In recent years, intravenously (IV) administered acetaminophen has become one of the most common perioperative analgesics. Despite its now-routine use, IV acetaminophen's analgesic comparative efficacy has never been compared with that of ketamine, a decades-old analgesic familiar to obstetricians, gynecologists, and anesthesiologists alike. This doubleblind clinical trial aimed to evaluate the analgesic effects of ketamine and IV acetaminophen on postoperative pain after abdominal hysterectomy. METHODS Eighty women aged 25-70 years old and meeting inclusion and exclusion criteria were randomly allocated into two groups of 40 to receive either IV acetaminophen or ketamine intraoperatively. Postoperatively, each patient had patient-controlled analgesia. Pain and sedation (Ramsay Sedation Scale) were documented based on the visual analog scale in the recovery room and at 4 hours, 6 hours, 12 hours, and 24 hours after the surgery. Hemodynamic changes, adverse medication effects, and the need for breakthrough meperidine were also recorded for both groups. Data were analyzed by repeated-measures analysis of variance. RESULTS Visual analog scale scores were significantly lower in the IV acetaminophen group at each time point (P<0.05), and this group required significantly fewer doses of breakthrough analgesics compared with the ketamine group (P=0.039). The two groups had no significant differences in terms of adverse effects. CONCLUSION Compared with ketamine, IV acetaminophen significantly improved postoperative pain after abdominal hysterectomy.
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Affiliation(s)
| | | | - Ognjen Visnjevac
- VA Western NY Healthcare System, University at Buffalo, Buffalo, NY, USA
| | | | | | - Nader D Nader
- VA Western NY Healthcare System, University at Buffalo, Buffalo, NY, USA
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310
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Moreno ML, Meza E, Ortega A, Caba M. The median preoptic nucleus exhibits circadian regulation and is involved in food anticipatory activity in rabbit pups. Chronobiol Int 2014; 31:515-22. [PMID: 24417519 DOI: 10.3109/07420528.2013.874354] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Rabbit pups are a natural model to study food anticipatory activity (FAA). Recently, we reported that three areas in the forebrain - the organum vasculosum of lamina terminalis, median preoptic nucleus (MnPO) and medial preoptic area - exhibit activation during FAA. Here, we examined the PER1 protein profile of these three forebrain regions in both nursed and fasted subjects. We found robust PER1 oscillations in the MnPO in nursed subjects, with high PER1 levels during FAA that persisted in fasted subjects. In conclusion, our data indicate that periodic nursing is a strong signal for PER1 oscillations in MnPO and future experiments are warranted to explore the specific role of this area in FAA.
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Affiliation(s)
- María Luisa Moreno
- Centro de Investigaciones Biomédicas, Universidad Veracruzana , Xalapa, Veracruz , Mexico
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311
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L-glutamate microinjection in the preoptic area increases brain and body temperature in freely moving rats. Neuroreport 2014; 25:28-33. [DOI: 10.1097/wnr.0000000000000035] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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312
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Ishiwata T. Role of serotonergic system in thermoregulation in rats. JOURNAL OF PHYSICAL FITNESS AND SPORTS MEDICINE 2014. [DOI: 10.7600/jpfsm.3.445] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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313
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Fuchs F, Damm J, Gerstberger R, Roth J, Rummel C. Activation of the inflammatory transcription factor nuclear factor interleukin-6 during inflammatory and psychological stress in the brain. J Neuroinflammation 2013; 10:140. [PMID: 24279606 PMCID: PMC4222273 DOI: 10.1186/1742-2094-10-140] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Accepted: 11/12/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The transcription factor nuclear factor interleukin 6 (NF-IL6) is known to be activated by various inflammatory stimuli in the brain. Interestingly, we recently detected NF-IL6-activation within the hypothalamus-pituitary-adrenal (HPA)-axis of rats after systemic lipopolysaccharide (LPS)-injection. Thus, the aim of the present study was to investigate whether NF-IL6 is activated during either, inflammatory, or psychological stress in the rat brain. METHODS Rats were challenged with either the inflammatory stimulus LPS (100 μg/kg, i.p.) or exposed to a novel environment. Core body temperature (Tb) and motor activity were monitored using telemetry, animals were killed at different time points, brains and blood removed, and primary cell cultures of the anterior pituitary lobe (AL) were investigated. Analyses were performed using immunohistochemistry, RT-PCR, and cytokine-specific bioassays. RESULTS Stress stimulation by a novel environment increased NF-IL6-immunoreactivity (IR) in the pituitary's perivascular macrophages and hypothalamic paraventricular cells and a rise in Tb lasting approximately 2 h. LPS stimulation lead to NF-IL6-IR in several additional cell types including ACTH-IR-positive corticotrope cells in vivo and in vitro. Two other proinflammatory transcription factors, namely signal transducer and activator of transcription (STAT)3 and NFκB, were significantly activated and partially colocalized with NF-IL6-IR in cells of the AL only after LPS-stimulation, but not following psychological stress. In vitro NF-IL6-activation was associated with induction and secretion of TNFα in folliculostellate cells, which could be antagonized by the JAK-STAT-inhibitor AG490. CONCLUSIONS We revealed, for the first time, that NF-IL6 activation occurs not only during inflammatory LPS stimulation, but also during psychological stress, that is, a novel environment. Both stressors were associated with time-dependent activation of NF-IL6 in different cell types of the brain and the pituitary. Moreover, while NF-IL6-IR was partially linked to STAT3 and NFκB activation, TNFα production, and ACTH-IR after LPS stimulation; this was not the case after exposure to a novel environment, suggesting distinct underlying signaling pathways. Overall, NF-IL6 can be used as a broad activation marker in the brain and might be of interest for therapeutic approaches not only during inflammatory but also psychological stress.
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Affiliation(s)
- Franziska Fuchs
- Department of Veterinary-Physiology and -Biochemistry, Justus-Liebig-University Giessen, Frankfurter Strasse 100, Giessen D-35392, Germany
| | - Jelena Damm
- Department of Veterinary-Physiology and -Biochemistry, Justus-Liebig-University Giessen, Frankfurter Strasse 100, Giessen D-35392, Germany
| | - Rüdiger Gerstberger
- Department of Veterinary-Physiology and -Biochemistry, Justus-Liebig-University Giessen, Frankfurter Strasse 100, Giessen D-35392, Germany
| | - Joachim Roth
- Department of Veterinary-Physiology and -Biochemistry, Justus-Liebig-University Giessen, Frankfurter Strasse 100, Giessen D-35392, Germany
| | - Christoph Rummel
- Department of Veterinary-Physiology and -Biochemistry, Justus-Liebig-University Giessen, Frankfurter Strasse 100, Giessen D-35392, Germany
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314
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Neuropsychopharmacology of a therapeutically used Andrographis paniculata extract: a preclinical study. ACTA ACUST UNITED AC 2013. [DOI: 10.1007/s13596-013-0140-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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315
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Soares DM, Ott D, Melo MCC, Souza GEP, Roth J. Chemokine ligand (CCL)-3 promotes an integrated febrile response when injected within pre-optic area (POA) of rats and induces calcium signaling in cells of POA microcultures but not TNF-α or IL-6 synthesis. Brain Behav Immun 2013; 34:120-9. [PMID: 23999490 DOI: 10.1016/j.bbi.2013.08.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Revised: 08/09/2013] [Accepted: 08/09/2013] [Indexed: 11/26/2022] Open
Abstract
Although studies have shown that chemokines are pyrogenic when injected into the brain, there are no data indicating which cell types and receptors in the CNS are employed by chemokines such as CCL3 (synonym: MIP-1α) to induce fever in rats. We aimed to study, whether CCL3 induces fever when injected directly into the thermoregulatory center within the pre-optic area (POA). Moreover, we investigated whether CCL3 activates cells from POA microcultures resulting in intracellular Ca++ mobilization and synthesis/release of TNF-α and IL-6. Microinjections of CCL3 into the POA induced a dose-dependent fever, which was accompanied by a decrease in tail skin temperature. The primary microcultures of the POA (from topographically excised rat pup brain tissue) were stimulated by bolus administrations of 100 μl CCL3 (0.1 or 0.01 μg) or sterile PBS as control. We evaluated the responses of 261 (30.89%) neurons, 346 (40.94%) astrocytes and 238 microglia cells (29.17%). Stimulation of rat POA microcultures with CCL3 was capable of inducing Ca++ signaling in 15.31% of all astrocytes and 5.75% of all neurons investigated. No cellular Ca++-signals were observed after overnight incubation of the cultures with antiCCR1 or antiCCR5 antibodies. CCL3 did not alter the release of the pyrogenic cytokines IL-6 or TNF-α into the supernatant of the cultures. In conclusion the present study shows for the first time that CCL-3 injected directly into the rat POA, evoked an integrated febrile response. In parallel this chemokine induces Ca++ signaling in astrocytes and neurons via both CCR1 and CCR5 receptors when administered to POA microcultures without stimulating the synthesis of TNF-α and IL-6. It is a possibility that CCL3-induced fever may occur via CCR1 and CCR5 receptors stimulation of astrocytes and neurons from POA.
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Affiliation(s)
- Denis Melo Soares
- Laboratory of Pharmacology, Faculty of Pharmaceutical Science, University of São Paulo, Ribeirão Preto, SP, Brazil.
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316
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Tanaka M, McKinley MJ, McAllen RM. Role of an excitatory preoptic-raphé pathway in febrile vasoconstriction of the rat's tail. Am J Physiol Regul Integr Comp Physiol 2013; 305:R1479-89. [PMID: 24133101 DOI: 10.1152/ajpregu.00401.2013] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Heat dissipation from the rat's tail is reduced in response to cold and during fever. The sympathetic premotor neurons for this mechanism, located in the medullary raphé, are under tonic inhibitory control from the preoptic area. In parallel with the inhibitory pathway, an excitatory pathway from the rostromedial preoptic region (RMPO) to the medullary raphé mediates the vasoconstrictor response to cold skin. Whether this applies also to the tail vasoconstrictor response in fever is unknown. Single- or a few-unit tail sympathetic nerve activity (SNA) was recorded in urethane-anesthetized, artificially ventilated rats. Experimental fever was induced by PGE2 injected into the lateral cerebral ventricle (50 ng in 1.5 μl icv) or into the RMPO (0.2 ng in 60 nl); in both cases, there was a robust increase in tail SNA and a delayed rise in core temperature. Microinjection of glutamate receptor antagonist kynurenate (50 mM, 120 nl) into the medullary raphé completely reversed the tail SNA response to intracerebroventricular or RMPO PGE2 injection. Inhibiting RMPO neurons by microinjecting glycine (0.5 M, 60 nl) or the GABAA receptor agonist, muscimol (2 mM, 30-60 nl), reduced the tail SNA response to PGE2 injected into the same site by approximately half. Vehicle injections into the medullary raphé or RMPO were without effect. These results suggest that the tail vasoconstrictor response during experimental fever depends on a glutamatergic excitatory synaptic relay in the medullary raphé and that an excitatory output signal from the RMPO contributes to the tail vasoconstrictor response during fever.
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Affiliation(s)
- Mutsumi Tanaka
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
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317
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Moreno ML, Meza E, Morgado E, Juárez C, Ramos-Ligonio A, Ortega A, Caba M. Activation of organum vasculosum of lamina terminalis, median preoptic nucleus, and medial preoptic area in anticipation of nursing in rabbit pups. Chronobiol Int 2013; 30:1272-82. [PMID: 24112031 DOI: 10.3109/07420528.2013.823980] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Rhythmic feeding in rabbit pups is a natural model to study food entrainment because, similar to rodents under a schedule of food restriction, these animals show food-anticipatory activity (FAA) prior to daily nursing. In rodents, several brain systems, including the orexinergic system, shift their activity to the restricted feeding schedule, and remain active when subjects are hungry. As the lamina terminalis and regions of the preoptic area participate in the control of behavioral arousal, it was hypothesized that these brain regions are also activated during FAA. Thus, the effects of daily milk ingestion on FOS protein expression in the organum vasculosum of lamina terminalis (OVLT), median preoptic nucleus (MnPO), and medial preoptic area (MPOA) were examined using immunohistochemistry before and after scheduled time of nursing in nursed and fasted subjects. Additionally, FOS expression was explored in orexin (ORX) cells in the lateral hypothalamic area and in the supraoptic nucleus (SON) because of their involvement in arousal and fluid ingestion, respectively. Pups were entrained by daily nursing, as indicated by a significant increase in locomotor behavior before scheduled time of nursing in both nursed and fasted subjects. FOS was significantly higher in the OVLT, MnPO, and MPOA at the time of nursing, and decreased 8 h later in nursed pups. In fasted subjects, this effect persisted in the OVLT, whereas in the MnPO and MPOA, values did not drop at 8 h later, but remained at the same level or higher than those at the time of scheduled nursing. In addition, FOS was significantly higher in ORX cells during FAA in nursed pups in comparison with 8 h later, but in fasted subjects it remained high during most fasting time points. Additionally, OVLT, SON, and ORX cells were activated 1.5 h after nursing. We conclude that the OVLT, MnPO, and MPOA, but not SON, may participate in FAA, as they show activation before suckling of periodic milk ingestion, and that sustained activation of the OVLT, MnPO, and MPOA by fasting may contribute to the high arousal state associated with food deprivation. In agreement with this, ORX cells also remain active after expected nursing, which is consistent with reports in other species.
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Affiliation(s)
- María Luisa Moreno
- Centro de Investigaciones Biomédicas, Universidad Veracruzana, Xalapa , Veracruz , México
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318
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Abstract
There is increasing evidence that cardiovascular control during sleep is relevant for cardiovascular risk. This evidence warrants increased experimental efforts to understand the physiological mechanisms of such control. This review summarizes current knowledge on autonomic features of sleep states [non-rapid-eye-movement sleep (NREMS) and rapid-eye-movement sleep (REMS)] and proposes some testable hypotheses concerning the underlying neural circuits. The physiological reduction of blood pressure (BP) during the night (BP dipping phenomenon) is mainly caused by generalized cardiovascular deactivation and baroreflex resetting during NREMS, which, in turn, are primarily a consequence of central autonomic commands. Central commands during NREMS may involve the hypothalamic ventrolateral preoptic area, central thermoregulatory and central baroreflex pathways, and command neurons in the pons and midbrain. During REMS, opposing changes in vascular resistance in different regional beds have the net effect of increasing BP compared with that of NREMS. In addition, there are transient increases in BP and baroreflex suppression associated with bursts of brain and skeletal muscle activity during REMS. These effects are also primarily a consequence of central autonomic commands, which may involve the midbrain periaqueductal gray, the sublaterodorsal and peduncular pontine nuclei, and the vestibular and raphe obscurus medullary nuclei. A key role in permitting physiological changes in BP during sleep may be played by orexin peptides released by hypothalamic neurons, which target the postulated neural pathways of central autonomic commands during NREMS and REMS. Experimental verification of these hypotheses may help reveal which central neural pathways and mechanisms are most essential for sleep-related changes in cardiovascular function.
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Affiliation(s)
- Alessandro Silvani
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Italy; and
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319
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Sladek CD, Johnson AK. Integration of thermal and osmotic regulation of water homeostasis: the role of TRPV channels. Am J Physiol Regul Integr Comp Physiol 2013; 305:R669-78. [PMID: 23883678 PMCID: PMC3798796 DOI: 10.1152/ajpregu.00270.2013] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Accepted: 07/12/2013] [Indexed: 12/21/2022]
Abstract
Maintenance of body water homeostasis is critical for preventing hyperthermia, because evaporative cooling is the most efficient means of dissipating excess body heat. Water homeostasis is achieved by regulation of water intake and water loss by the kidneys. The former is achieved by sensations of thirst that motivate water acquisition, whereas the latter is regulated by the antidiuretic action of vasopressin. Vasopressin secretion and thirst are stimulated by increases in the osmolality of the extracellular fluid as well as decreases in blood pressure and/or blood volume, signals that are precipitated by water depletion associated with the excess evaporative water loss required to prevent hyperthermia. In addition, they are stimulated by increases in body temperature. The sites and molecular mechanisms involved in integrating thermal and osmotic regulation of thirst and vasopressin secretion are reviewed here with a focus on the role of the thermal and mechanosensitive transient receptor potential-vanilloid (TRPV) family of ion channels.
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Affiliation(s)
- Celia D Sladek
- Department of Physiology and Biophysics, University of Colorado School of Medicine, Aurora, Colorado; and
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320
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Wanner SP, Yoshida K, Kulchitsky VA, Ivanov AI, Kanosue K, Romanovsky AA. Lipopolysaccharide-induced neuronal activation in the paraventricular and dorsomedial hypothalamus depends on ambient temperature. PLoS One 2013; 8:e75733. [PMID: 24069444 PMCID: PMC3777970 DOI: 10.1371/journal.pone.0075733] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Accepted: 08/16/2013] [Indexed: 01/24/2023] Open
Abstract
Systemic inflammatory response syndrome is associated with either fever or hypothermia, but the mechanisms responsible for switching from one to the other are unknown. In experimental animals, systemic inflammation is often induced by bacterial lipopolysaccharide (LPS). To identify the diencephalic and brainstem structures involved in the fever-hypothermia switch, we studied the expression of c-Fos protein, a marker of neuronal activation, in rats treated with the same high dose of LPS (0.5 mg/kg, intravenously) either in a thermoneutral (30 °C) or cool (24 °C) environment. At 30 °C, LPS caused fever; at 24 °C, the same dose caused profound hypothermia. Both fever and hypothermia were associated with the induction of c-Fos in many brain areas, including several structures of the anterior preoptic, paraventricular, lateral, and dorsal hypothalamus, the bed nucleus of the stria terminalis, the posterior pretectal nucleus, ventrolateral periaqueductal gray, lateral parabrachial nucleus, area postrema, and nucleus of the solitary tract. Every brain area studied showed a comparable response to LPS at the two different ambient temperatures used, with the exception of two areas: the dorsomedial hypothalamic nucleus (DMH), which we studied together with the adjacent dorsal hypothalamic area (DA), and the paraventricular hypothalamic nucleus (PVH). Both structures had much stronger c-Fos expression during LPS hypothermia than during fever. We propose that PVH and DMH/DA neurons are involved in a circuit, which - depending on the ambient temperature - determines whether the thermoregulatory response to bacterial LPS will be fever or hypothermia.
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Affiliation(s)
- Samuel P. Wanner
- Systemic Inflammation Laboratory (FeverLab), Trauma Research, St. Joseph's Hospital and Medical Center, Phoenix, Arizona, United States of America
- School of Physical Education, Physiotherapy and Occupational Therapy, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Kyoko Yoshida
- Department of Physiology, School of Allied Health Sciences, Faculty of Medicine, Osaka University, Osaka, Japan
| | - Vladimir A. Kulchitsky
- Systemic Inflammation Laboratory (FeverLab), Trauma Research, St. Joseph's Hospital and Medical Center, Phoenix, Arizona, United States of America
- Institute of Physiology, National Academy of Sciences, Minsk, Belarus
| | - Andrei I. Ivanov
- Systemic Inflammation Laboratory (FeverLab), Trauma Research, St. Joseph's Hospital and Medical Center, Phoenix, Arizona, United States of America
- Department of Human and Molecular Genetics and Virginia Institute of Molecular Medicine, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Kazuyuki Kanosue
- Department of Physiology, School of Allied Health Sciences, Faculty of Medicine, Osaka University, Osaka, Japan
- Graduate School of Sport Sciences, Waseda University, Tokorozawa, Japan
| | - Andrej A. Romanovsky
- Systemic Inflammation Laboratory (FeverLab), Trauma Research, St. Joseph's Hospital and Medical Center, Phoenix, Arizona, United States of America
- Interdisciplinary Graduate Program in Neuroscience, Arizona State University, Tempe, Arizona, United States of America
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321
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Ganella DE, Ma S, Gundlach AL. Relaxin-3/RXFP3 Signaling and Neuroendocrine Function - A Perspective on Extrinsic Hypothalamic Control. Front Endocrinol (Lausanne) 2013; 4:128. [PMID: 24065955 PMCID: PMC3776160 DOI: 10.3389/fendo.2013.00128] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Accepted: 09/02/2013] [Indexed: 01/08/2023] Open
Abstract
Complex neural circuits within the hypothalamus that govern essential autonomic processes and associated behaviors signal using amino acid and monoamine transmitters and a variety of neuropeptide (hormone) modulators, often via G-protein coupled receptors (GPCRs) and associated cellular pathways. Relaxin-3 is a recently identified neuropeptide that is highly conserved throughout evolution. Neurons expressing relaxin-3 are located in the brainstem, but broadly innervate the entire limbic system including the hypothalamus. Extensive anatomical data in rodents and non-human primate, and recent regulatory and functional data, suggest relaxin-3 signaling via its cognate GPCR, RXFP3, has a broad range of effects on neuroendocrine function associated with stress responses, feeding and metabolism, motivation and reward, and possibly sexual behavior and reproduction. Therefore, this article aims to highlight the growing appreciation of the relaxin-3/RXFP3 system as an important "extrinsic" regulator of the neuroendocrine axis by reviewing its neuroanatomy and its putative roles in arousal-, stress-, and feeding-related behaviors and links to associated neural substrates and signaling networks. Current evidence identifies RXFP3 as a potential therapeutic target for treatment of neuroendocrine disorders and related behavioral dysfunction.
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Affiliation(s)
- Despina E. Ganella
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Melbourne, VIC, Australia
- Department of Biochemistry and Molecular Biology, The University of Melbourne, Melbourne, VIC, Australia
| | - Sherie Ma
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Melbourne, VIC, Australia
| | - Andrew L. Gundlach
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Melbourne, VIC, Australia
- Florey Department of Neuroscience and Mental Health, The University of Melbourne, Melbourne, VIC, Australia
- Department of Anatomy and Neuroscience, The University of Melbourne, Melbourne, VIC, Australia
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322
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Boltaña S, Rey S, Roher N, Vargas R, Huerta M, Huntingford FA, Goetz FW, Moore J, Garcia-Valtanen P, Estepa A, Mackenzie S. Behavioural fever is a synergic signal amplifying the innate immune response. Proc Biol Sci 2013; 280:20131381. [PMID: 23843398 PMCID: PMC3730603 DOI: 10.1098/rspb.2013.1381] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Behavioural fever, defined as an acute change in thermal preference driven by pathogen recognition, has been reported in a variety of invertebrates and ectothermic vertebrates. It has been suggested, but so far not confirmed, that such changes in thermal regime favour the immune response and thus promote survival. Here, we show that zebrafish display behavioural fever that acts to promote extensive and highly specific temperature-dependent changes in the brain transcriptome. The observed coupling of the immune response to fever acts at the gene–environment level to promote a robust, highly specific time-dependent anti-viral response that, under viral infection, increases survival. Fish that are not offered a choice of temperatures and that therefore cannot express behavioural fever show decreased survival under viral challenge. This phenomenon provides an underlying explanation for the varied functional responses observed during systemic fever. Given the effects of behavioural fever on survival and the fact that it exists across considerable phylogenetic space, such immunity–environment interactions are likely to be under strong positive selection.
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Affiliation(s)
- Sebastian Boltaña
- Institut de Biotecnologia i de Biomedicina, Universitat Autonoma de Barcelona, , Bellaterra (Barcelona) 08193, Spain
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323
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Takahashi Y, Zhang W, Sameshima K, Kuroki C, Matsumoto A, Sunanaga J, Kono Y, Sakurai T, Kanmura Y, Kuwaki T. Orexin neurons are indispensable for prostaglandin E2-induced fever and defence against environmental cooling in mice. J Physiol 2013; 591:5623-43. [PMID: 23959674 DOI: 10.1113/jphysiol.2013.261271] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
We recently showed using prepro-orexin knockout (ORX-KO) mice and orexin neuron-ablated (ORX-AB) mice that orexin neurons in the hypothalamus, but not orexin peptides per se, are indispensable for stress-induced thermogenesis. To examine whether orexin neurons are more generally involved in central thermoregulatory mechanisms, we applied other forms of thermogenic perturbations, including brain prostaglandin E2 (PGE2) injections which mimic inflammatory fever and environmental cold exposure, to ORX-KO mice, ORX-AB mice and their wild-type (WT) litter mates. ORX-AB mice, but not ORX-KO mice, exhibited a blunted PGE2-induced fever and intolerance to cold (5°C) exposure, and these findings were similar to the results previously obtained with stress-induced thermogenesis. PGE2-induced shivering was also attenuated in ORX-AB mice. Both mutants responded similarly to environmental heating (39°C). In WT and ORX-KO mice, the administration of PGE2 and cold exposure activated orexin neurons, as revealed by increased levels of expression of c-fos. Injection of retrograde tracer into the medullary raphe nucleus revealed direct and indirect projection from the orexin neurons, of which the latter seemed to be preserved in the ORX-AB mice. In addition, we found that glutamate receptor antagonists (D-(-)-2-amino-5-phosphonopentanoic acid and 6-cyano-7-nitroquinoxaline-2,3-dione) but not orexin receptor antagonists (SB334867 and OX2 29) successfully inhibited PGE2-induced fever in WT mice. These results suggest that orexin neurons are important in general thermogenic processes, and their importance is not restricted to stress-induced thermogenesis. In addition, these results indicate the possible involvement of glutamate in orexin neurons implicated in PGE2-induced fever.
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Affiliation(s)
- Yoshiko Takahashi
- T. Kuwaki: Department of Physiology, Kagoshima University Graduate School of Medical and Dental Sciences, Sakuragaoka 8-35-1, Kagoshima 890-8544, Japan.
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324
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The Role of Neurotransmitters in Protection against Amyloid- β Toxicity by KiSS-1 Overexpression in SH-SY5Y Neurons. ISRN NEUROSCIENCE 2013; 2013:253210. [PMID: 24967306 PMCID: PMC4045539 DOI: 10.1155/2013/253210] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Accepted: 06/19/2013] [Indexed: 12/21/2022]
Abstract
Recent studies have suggested that the kisspeptin (KP) and kissorphin (KSO) peptides have neuroprotective actions against the Alzheimer's amyloid-β (Aβ) peptide. Overexpression of the human KiSS-1 gene that codes for KP and KSO peptides in SH-SY5Y neurons has also been shown to inhibit Aβ neurotoxicity. The in vivo actions of KP include activation of neuroendocrine and neurotransmitter systems. The present study used antagonists of KP, neuropeptide FF (NPFF), opioids, oxytocin, estrogen, adrenergic, cholinergic, dopaminergic, serotonergic, and γ-aminobutyric acid (GABA) receptors plus inhibitors of catalase, cyclooxygenase, nitric oxide synthase, and the mitogen activated protein kinase cascade to characterize the KiSS-1 gene overexpression neuroprotection against Aβ cell model. The results showed that KiSS-1 overexpression is neuroprotective against Aβ and the action appears to involve the KP or KSO peptide products of KiSS-1 processing. The mechanism of neuroprotection does not involve the activation of the KP or NPFF receptors. Opioids play a role in the toxicity of Aβ in the KiSS-1 overexpression system and opioid antagonists naloxone or naltrexone inhibited Aβ toxicity. The mechanism of KiSS-1 overexpression induced protection against Aβ appears to have an oxytocin plus a cyclooxygenase dependent component, with the oxytocin antagonist atosiban and the cyclooxygenase inhibitor SC-560 both enhancing the toxicity of Aβ.
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325
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Yoneshiro T, Aita S, Matsushita M, Kayahara T, Kameya T, Kawai Y, Iwanaga T, Saito M. Recruited brown adipose tissue as an antiobesity agent in humans. J Clin Invest 2013; 123:3404-8. [PMID: 23867622 DOI: 10.1172/jci67803] [Citation(s) in RCA: 691] [Impact Index Per Article: 62.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2012] [Accepted: 05/15/2013] [Indexed: 12/14/2022] Open
Abstract
Brown adipose tissue (BAT) burns fat to produce heat when the body is exposed to cold and plays a role in energy metabolism. Using fluorodeoxyglucose-positron emission tomography and computed tomography, we previously reported that BAT decreases with age and thereby accelerates age-related accumulation of body fat in humans. Thus, the recruitment of BAT may be effective for body fat reduction. In this study, we examined the effects of repeated stimulation by cold and capsinoids (nonpungent capsaicin analogs) in healthy human subjects with low BAT activity. Acute cold exposure at 19°C for 2 hours increased energy expenditure (EE). Cold-induced increments of EE (CIT) strongly correlated with BAT activity independently of age and fat-free mass. Daily 2-hour cold exposure at 17°C for 6 weeks resulted in a parallel increase in BAT activity and CIT and a concomitant decrease in body fat mass. Changes in BAT activity and body fat mass were negatively correlated. Similarly, daily ingestion of capsinoids for 6 weeks increased CIT. These results demonstrate that human BAT can be recruited even in individuals with decreased BAT activity, thereby contributing to body fat reduction.
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Affiliation(s)
- Takeshi Yoneshiro
- Department of Anatomy, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
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326
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Virtue S, Vidal-Puig A. Assessment of brown adipose tissue function. Front Physiol 2013; 4:128. [PMID: 23760815 PMCID: PMC3671177 DOI: 10.3389/fphys.2013.00128] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Accepted: 05/16/2013] [Indexed: 11/25/2022] Open
Abstract
In this review we discuss practical considerations for the assessment of brown adipose tissue in rodent models, focusing on mice. The central aim of the review is to provide a critical appraisal of the utility of specialized techniques for assessing brown adipose tissue function in vivo. We cover several of the most common specialized methods for analysing brown adipose tissue function in vivo, including assessment of maximal thermogenic capacity by indirect calorimetry and the measurement of sympathetic tone to brown adipose tissue. While these techniques are powerful, they are not readily available to all laboratories; therefore we also cover several simple measurements that, particularly in combination, can be used to determine if a mouse model is likely to have alterations in brown adipose tissue function. Such techniques include: pair feeding, analysis of brown adipose tissue lipid content and mRNA and protein markers of brown adipose tissue activation.
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Affiliation(s)
- Sam Virtue
- Metabolic Research Laboratories, Addenbrooke's Treatment Centre, Institute of Metabolic Science, Addenbrooke's Hospital, University of CambridgeCambridge, UK
| | - Antonio Vidal-Puig
- Metabolic Research Laboratories, Addenbrooke's Treatment Centre, Institute of Metabolic Science, Addenbrooke's Hospital, University of CambridgeCambridge, UK
- Wellcome Trust Sanger InstituteCambridge, UK
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327
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Schiefecker AJ, Pfausler B, Beer R, Sohm F, Sabo J, Knauseder V, Fischer M, Dietmann A, Hackl WO, Thomé C, Schmutzhard E, Helbok R. Parenteral diclofenac infusion significantly decreases brain-tissue oxygen tension in patients with poor-grade aneurysmal subarachnoid hemorrhage. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2013; 17:R88. [PMID: 23663770 PMCID: PMC3706816 DOI: 10.1186/cc12714] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Accepted: 05/12/2013] [Indexed: 01/20/2023]
Abstract
Introduction Diclofenac, a nonsteroidal antiinflammatory drug, is commonly used as antipyretic therapy in intensive care. The purpose of this study was to investigate the effects of parenteral diclofenac infusion on brain homeostasis, including brain-tissue oxygen tension (PbtO2) and brain metabolism after aneurysmal subarachnoid hemorrhage (aSAH). Methods We conducted a prospective, observational study with retrospective analysis of 21 consecutive aSAH patients with multimodal neuromonitoring. Cerebral perfusion pressure (CPP), mean arterial pressure (MAP), intracranial pressure (ICP), body temperature, and PbtO2 were analyzed after parenteral diclofenac infusion administered over a 34-minute period (20 to 45 IQR). Data are given as mean ± standard error of mean and median with interquartile range (IQR), as appropriate. Time-series data were analyzed by using a general linear model extended by generalized estimation equations (GEEs). Results One-hundred twenty-three interventions were analyzed. Body temperature decreased from 38.3°C ± 0.05°C by 0.8°C ± 0.06°C (P < 0.001). A 10% decrease in MAP and CPP (P < 0.001) necessitated an increase of vasopressors in 26% (n = 32), colloids in 33% (n = 41), and crystalloids in 5% (n = 7) of interventions. PbtO2 decreased by 13% from a baseline value of 28.1 ± 2.2 mm Hg, resulting in brain-tissue hypoxia (PbtO2 <20 mm Hg) in 38% (n = 8) of patients and 35% (n = 43) of interventions. PbtO2 <30 mm Hg before intervention was associated with brain-tissue hypoxia after parenteral diclofenac infusion (likelihood ratio, 40; AUC, 93%; 95% confidence interval (CI), 87% to 99%; P < 0.001). Cerebral metabolism showed no significant changes after parenteral diclofenac infusion. Conclusions Parenteral diclofenac infusion after aSAH effectively reduces body temperature, but may lead to CPP decrease and brain-tissue hypoxia, which were both associated with poor outcome after aSAH.
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328
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Groessl F, Jeong JH, Talmage DA, Role LW, Jo YH. Overnight fasting regulates inhibitory tone to cholinergic neurons of the dorsomedial nucleus of the hypothalamus. PLoS One 2013; 8:e60828. [PMID: 23585854 PMCID: PMC3621823 DOI: 10.1371/journal.pone.0060828] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Accepted: 03/03/2013] [Indexed: 11/19/2022] Open
Abstract
The dorsomedial nucleus of the hypothalamus (DMH) contributes to the regulation of overall energy homeostasis by modulating energy intake as well as energy expenditure. Despite the importance of the DMH in the control of energy balance, DMH-specific genetic markers or neuronal subtypes are poorly defined. Here we demonstrate the presence of cholinergic neurons in the DMH using genetically modified mice that express enhanced green florescent protein (eGFP) selectively in choline acetyltransferase (Chat)-neurons. Overnight food deprivation increases the activity of DMH cholinergic neurons, as shown by induction of fos protein and a significant shift in the baseline resting membrane potential. DMH cholinergic neurons receive both glutamatergic and GABAergic synaptic input, but the activation of these neurons by an overnight fast is due entirely to decreased inhibitory tone. The decreased inhibition is associated with decreased frequency and amplitude of GABAergic synaptic currents in the cholinergic DMH neurons, while glutamatergic synaptic transmission is not altered. As neither the frequency nor amplitude of miniature GABAergic or glutamatergic postsynaptic currents is affected by overnight food deprivation, the fasting-induced decrease in inhibitory tone to cholinergic neurons is dependent on superthreshold activity of GABAergic inputs. This study reveals that cholinergic neurons in the DMH readily sense the availability of nutrients and respond to overnight fasting via decreased GABAergic inhibitory tone. As such, altered synaptic as well as neuronal activity of DMH cholinergic neurons may play a critical role in the regulation of overall energy homeostasis.
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Affiliation(s)
- Florian Groessl
- Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, New York, United States of America
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter, Vienna, Vienna, Austria
| | - Jae Hoon Jeong
- Departments of Medicine and Molecular Pharmacology, Albert Einstein College of Medicine of Yeshiva University, Bronx, New York, United States of America
| | - David A. Talmage
- Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, New York, United States of America
| | - Lorna W. Role
- Department of Neurobiology and Behavior, Stony Brook University, Stony Brook, New York, United States of America
| | - Young-Hwan Jo
- Departments of Medicine and Molecular Pharmacology, Albert Einstein College of Medicine of Yeshiva University, Bronx, New York, United States of America
- * E-mail:
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329
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Temperaturregulationsstörungen im Kindesalter. Monatsschr Kinderheilkd 2013. [DOI: 10.1007/s00112-012-2783-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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330
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Horne J. Why REM sleep? Clues beyond the laboratory in a more challenging world. Biol Psychol 2013; 92:152-68. [DOI: 10.1016/j.biopsycho.2012.10.010] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2012] [Revised: 09/17/2012] [Accepted: 10/11/2012] [Indexed: 11/16/2022]
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331
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Nascimento A, Bernardi M, Pecorari V, Massoco C, Felicio L. Temporal analysis of lipopolysaccharide-induced sickness behavior in virgin and lactating female rats. Neuroimmunomodulation 2013; 20:305-12. [PMID: 23887067 DOI: 10.1159/000350705] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Accepted: 03/13/2013] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVES Lipopolysaccharide (LPS), an endotoxin that originates from the cell wall of Gram-negative bacteria, activates the immune system to release proinflammatory cytokines and to induce sickness behavior. The present study sought to characterize the time-dependent effects of LPS on fever, body weight, and food and water consumption in female virgin and lactating rats exposed to an LPS dose previously reported to induce sickness behavior in pregnant female rats. METHODS Virgin female Wistar rats in the estrous phase and lactating female Wistar rats on the third day of lactation received 100 µg/kg LPS or saline solution. Tympanic temperature, body weight, and food and water consumption were assessed 0, 2, 24, 48, 72, 96, and 120 h after treatment. RESULTS In lactating female rats, tympanic temperature was attenuated compared with virgin females. Food consumption and body weight gain in both groups decreased, but lactating rats consumed more food than virgin rats. Water consumption increased at different time points. CONCLUSION LPS exposure induced several signs of sickness behavior, including decreases in food consumption and body weight gain, and induced adipsia in both virgin and lactating female rats. Because the time course and profile of fever varied between lactating and nonlactating animals, these responses appeared to depend on the physiological state of female animals.
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Affiliation(s)
- Amanda Nascimento
- Department of Pathology, School of Veterinary Medicine, University of São Paulo, São Paulo, Brazil
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332
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Shibasaki M, Okazaki K, Inoue Y. Aging and thermoregulation. JOURNAL OF PHYSICAL FITNESS AND SPORTS MEDICINE 2013. [DOI: 10.7600/jpfsm.2.37] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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The circadian system and the balance of the autonomic nervous system. HANDBOOK OF CLINICAL NEUROLOGY 2013; 117:173-91. [DOI: 10.1016/b978-0-444-53491-0.00015-8] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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334
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Holtzclaw BJ. Managing Fever and Febrile Symptoms in HIV: Evidence-Based Approaches. J Assoc Nurses AIDS Care 2013; 24:S86-102. [DOI: 10.1016/j.jana.2012.07.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2012] [Accepted: 07/24/2012] [Indexed: 11/24/2022]
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335
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ATP induces mild hypothermia in rats but has a strikingly detrimental impact on focal cerebral ischemia. J Cereb Blood Flow Metab 2013; 33:jcbfm2012146. [PMID: 23072747 PMCID: PMC3597371 DOI: 10.1038/jcbfm.2012.146] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Ischemic stroke is a devastating condition lacking effective therapies. A promising approach to attenuate ischemic injury is mild hypothermia. Recent studies show that adenosine nucleotides can induce hypothermia in mice. The purpose of the present study was to test the hypothesis that adenosine 5'-triphosphate (ATP) induces mild hypothermia in rats and reduces ischemic brain injury. We found that intraperitoneal injections of ATP decreased core body temperature in a dose-dependent manner; the dose appropriate for mild hypothermia was 2 g/kg. When ATP-induced hypothermia was applied to stroke induced by middle cerebral artery occlusion, however, a neuroprotective effect was not observed. Instead, the infarct volume grew even larger in ATP-treated rats. This was accompanied by an increased rate of seizure events, hemorrhagic transformation, and higher mortality. Continuous monitoring of physiologic parameters revealed that ATP reduced heartbeat rate and blood pressure. ATP also increased blood glucose, accompanied by severe acidosis and hypocalcemia. Western blotting showed that ATP decreased levels of both phospho-Akt and total-Akt in the cortex. Our results reveal that, despite inducing hypothermia, ATP is not appropriate for protecting the brain against stroke. Instead, we show for the first time that ATP treatment is associated with exaggerated ischemic outcomes and dangerous systemic side effects.
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336
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Hur J, Ozgür A, Xiang Z, He Y. Identification of fever and vaccine-associated gene interaction networks using ontology-based literature mining. J Biomed Semantics 2012; 3:18. [PMID: 23256563 PMCID: PMC3599673 DOI: 10.1186/2041-1480-3-18] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2012] [Accepted: 11/23/2012] [Indexed: 12/03/2022] Open
Abstract
Background Fever is one of the most common adverse events of vaccines. The detailed mechanisms of fever and vaccine-associated gene interaction networks are not fully understood. In the present study, we employed a genome-wide, Centrality and Ontology-based Network Discovery using Literature data (CONDL) approach to analyse the genes and gene interaction networks associated with fever or vaccine-related fever responses. Results Over 170,000 fever-related articles from PubMed abstracts and titles were retrieved and analysed at the sentence level using natural language processing techniques to identify genes and vaccines (including 186 Vaccine Ontology terms) as well as their interactions. This resulted in a generic fever network consisting of 403 genes and 577 gene interactions. A vaccine-specific fever sub-network consisting of 29 genes and 28 gene interactions was extracted from articles that are related to both fever and vaccines. In addition, gene-vaccine interactions were identified. Vaccines (including 4 specific vaccine names) were found to directly interact with 26 genes. Gene set enrichment analysis was performed using the genes in the generated interaction networks. Moreover, the genes in these networks were prioritized using network centrality metrics. Making scientific discoveries and generating new hypotheses were possible by using network centrality and gene set enrichment analyses. For example, our study found that the genes in the generic fever network were more enriched in cell death and responses to wounding, and the vaccine sub-network had more gene enrichment in leukocyte activation and phosphorylation regulation. The most central genes in the vaccine-specific fever network are predicted to be highly relevant to vaccine-induced fever, whereas genes that are central only in the generic fever network are likely to be highly relevant to generic fever responses. Interestingly, no Toll-like receptors (TLRs) were found in the gene-vaccine interaction network. Since multiple TLRs were found in the generic fever network, it is reasonable to hypothesize that vaccine-TLR interactions may play an important role in inducing fever response, which deserves a further investigation. Conclusions This study demonstrated that ontology-based literature mining is a powerful method for analyzing gene interaction networks and generating new scientific hypotheses.
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Affiliation(s)
- Junguk Hur
- Unit for Laboratory Animal Medicine, University of Michigan, 48109, Ann Arbor, MI, USA.
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337
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Martinez N, Risco C, Lima F, Bisinotto R, Greco L, Ribeiro E, Maunsell F, Galvão K, Santos J. Evaluation of peripartal calcium status, energetic profile, and neutrophil function in dairy cows at low or high risk of developing uterine disease. J Dairy Sci 2012; 95:7158-72. [DOI: 10.3168/jds.2012-5812] [Citation(s) in RCA: 255] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2012] [Accepted: 08/22/2012] [Indexed: 11/19/2022]
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338
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Osaka T. Hypoxia-induced hypothermia mediated by the glutamatergic transmission in the lateral preoptic area. Neuroscience 2012; 226:73-80. [DOI: 10.1016/j.neuroscience.2012.09.033] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Revised: 09/09/2012] [Accepted: 09/11/2012] [Indexed: 10/27/2022]
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339
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Inoue Y, Nakahara K, Maruyama K, Suzuki Y, Hayashi Y, Kangawa K, Murakami N. Central and peripheral des-acyl ghrelin regulates body temperature in rats. Biochem Biophys Res Commun 2012; 430:278-83. [PMID: 23159626 DOI: 10.1016/j.bbrc.2012.10.137] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2012] [Accepted: 10/31/2012] [Indexed: 01/23/2023]
Abstract
In the present study using rats, we demonstrated that central and peripheral administration of des-acyl ghrelin induced a decrease in the surface temperature of the back, and an increase in the surface temperature of the tail, although the effect of peripheral administration was less marked than that of central administration. Furthermore, these effects of centrally administered des-acyl ghrelin could not be prevented by pretreatment with [D-Lys3]-GHRP-6 GH secretagogue receptor 1a (GHS-R1a) antagonists. Moreover, these actions of des-acyl ghrelin on body temperature were inhibited by the parasympathetic nerve blocker methylscopolamine but not by the sympathetic nerve blocker timolol. Using immunohistochemistry, we confirmed that des-acyl ghrelin induced an increase of cFos expression in the median preoptic nucleus (MnPO). Additionally, we found that des-acyl ghrelin dilated the aorta and tail artery in vitro. These results indicate that centrally administered des-acyl ghrelin regulates body temperature via the parasympathetic nervous system by activating neurons in the MnPO through interactions with a specific receptor distinct from the GHS-R1a, and that peripherally administered des-acyl ghrelin acts on the central nervous system by passing through the blood-brain barrier, whereas it exerts a direct action on the peripheral vascular system.
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Affiliation(s)
- Yoshiyuki Inoue
- Department of Veterinary Physiology, Faculty of Agriculture, University of Miyazaki, Miyazaki 889-2192, Japan
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340
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Kälin K, Knechtle B, Rüst CA, Mydlak K, Rosemann T. Running a marathon from -45°C to +55°C in a climate chamber: a case study. Open Access J Sports Med 2012; 3:131-45. [PMID: 24198596 PMCID: PMC3781908 DOI: 10.2147/oajsm.s36808] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND We describe a runner who completed a self-paced marathon (42.195 km) in a climate chamber with a temperature difference of 100°C, starting at an ambient temperature (Tambient) of -45°C and finishing at an Tambient of +55°C. METHODS Tambient was set at -45°C at the start, and was steadily increased at a rate of 1°C at 4.5-minute intervals to +55°C. Before the start, after every 10.5 km, and at the end of the marathon, body mass, urine, and sweat production were measured and samples of venous blood and urine were collected. The runner's temperature was recorded every 10 seconds at four sites, ie, the rectum for body core temperature (Tcore), and at the forehead, right wrist, and right ankle for surface temperatures (Tskin). RESULTS The subject took 6.5 hours to complete the marathon, during which Tcore varied by 0.9°C (start 37.5°C, peak 38.4°C). The largest difference (∆) of Tskin was recorded at the ankle (∆16°C). The calculated amount of sweat produced increased by 888% from baseline. In the blood samples, myoglobin (+250%) showed the highest change. Of the pituitary hormones, somatotropic hormone (+391%) and prolactin (+221%) increased the most. Regarding fluid regulation hormones, renin (+1145%) and aldosterone (+313%) showed the greatest increase. CONCLUSION These results show that running a marathon in a climate chamber with a total ∆Tambient of 100°C is possible, and that the Tambient to Tcore relationship is maintained. These results may offer insight into regulatory mechanisms to avoid hypothermia and hyperthermia. The same study is to be performed using more subjects with the same characteristics to validate the present findings.
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Affiliation(s)
- Kaspar Kälin
- Institute of General Practice and Health Services Research, University of Zurich, Zurich
| | - Beat Knechtle
- Institute of General Practice and Health Services Research, University of Zurich, Zurich
- Gesundheitszentrum St Gallen, St Gallen, Switzerland
| | | | - Karsten Mydlak
- Gemeinschaftslabor Cottbus, Medizinisches Versorgungszentrum für Labormedizin, Mikrobiologie und Infektionsepidemiologie, Cottbus, Germany
| | - Thomas Rosemann
- Institute of General Practice and Health Services Research, University of Zurich, Zurich
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341
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Lo Martire V, Silvani A, Bastianini S, Berteotti C, Zoccoli G. Effects of ambient temperature on sleep and cardiovascular regulation in mice: the role of hypocretin/orexin neurons. PLoS One 2012; 7:e47032. [PMID: 23056568 PMCID: PMC3466227 DOI: 10.1371/journal.pone.0047032] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2012] [Accepted: 09/07/2012] [Indexed: 11/18/2022] Open
Abstract
The central neural pathways underlying the physiological coordination between thermoregulation and the controls of the wake-sleep behavior and cardiovascular function remain insufficiently understood. Growing evidence supports the involvement of hypocretin (orexin) peptides in behavioral, cardiovascular, and thermoregulatory functions. We investigated whether the effects of ambient temperature on wake-sleep behavior and cardiovascular control depend on the hypothalamic neurons that release hypocretin peptides. Orexin-ataxin3 transgenic mice with genetic ablation of hypocretin neurons (n = 11) and wild-type controls (n = 12) were instrumented with electrodes for sleep scoring and a telemetric blood pressure transducer. Simultaneous sleep and blood pressure recordings were performed on freely-behaving mice at ambient temperatures ranging between mild cold (20°C) and the thermoneutral zone (30°C). In both mouse groups, the time spent awake and blood pressure were higher at 20°C than at 30°C. The cold-related increase in blood pressure was significantly smaller in rapid-eye-movement sleep (REMS) than either in non-rapid-eye-movement sleep (NREMS) or wakefulness. Blood pressure was higher in wakefulness than either in NREMS or REMS at both ambient temperatures. This effect was significantly blunted in orexin-ataxin3 mice irrespective of ambient temperature and particularly during REMS. These data demonstrate that hypocretin neurons are not a necessary part of the central pathways that coordinate thermoregulation with wake-sleep behavior and cardiovascular control. Data also support the hypothesis that hypocretin neurons modulate changes in blood pressure between wakefulness and the sleep states. These concepts may have clinical implications in patients with narcolepsy with cataplexy, who lack hypocretin neurons.
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Affiliation(s)
- Viviana Lo Martire
- Department of Human and General Physiology, Alma Mater Studiorum – University of Bologna, Bologna, Italy
| | - Alessandro Silvani
- Department of Human and General Physiology, Alma Mater Studiorum – University of Bologna, Bologna, Italy
| | - Stefano Bastianini
- Department of Human and General Physiology, Alma Mater Studiorum – University of Bologna, Bologna, Italy
| | - Chiara Berteotti
- Department of Human and General Physiology, Alma Mater Studiorum – University of Bologna, Bologna, Italy
| | - Giovanna Zoccoli
- Department of Human and General Physiology, Alma Mater Studiorum – University of Bologna, Bologna, Italy
- * E-mail:
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342
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Osaka T. Thermoregulatory responses elicited by microinjection of L-glutamate and its interaction with thermogenic effects of GABA and prostaglandin E2 in the preoptic area. Neuroscience 2012; 226:156-64. [PMID: 22986159 DOI: 10.1016/j.neuroscience.2012.08.048] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Revised: 08/09/2012] [Accepted: 08/24/2012] [Indexed: 11/30/2022]
Abstract
The aim of the present study was to investigate the thermoregulatory effects of neuronal activation with sodium L-glutamate (glutamate) in the preoptic area (POA) of the hypothalamus and to examine its possible interaction with the thermogenic effects of GABA and prostaglandin E(2) (PGE(2)). Unilateral microinjection of glutamate (5 nmol) into the lateral POA or its vicinity elicited a prompt increase in tail skin temperature and simultaneous decreases in the O(2) consumption rate (VO(2)), heart rate, and colonic temperature in urethane-chloralose-anesthetized rats. A central subpopulation of these sites at around the level of bregma was also responsive to the thermogenic and tachycardic effects of GABA (30 nmol). Although the microinjection of GABA into nearby sites elicited no direct effect, it greatly attenuated the hypothermic effects of glutamate subsequently administered to the same site. These results suggest that activation of the lateral POA elicited heat-loss responses and that its central part provided a tonic inhibitory drive toward heat production and tail vasoconstriction. On the other hand, the microinjection of glutamate elicited initial small decreases and subsequent large increases in VO(2) and heart rate in the rostromedial POA. However, no thermoregulatory response was elicited by the microinjection of glutamate at sites where the microinjection of PGE(2) (35 fmol) elicited thermogenic, tachycardic and hyperthermic responses. These results may suggest that the rostromedial POA contained two glutamate-responsive cell groups that had opposite influences on thermoregulation and that the locus that was highly sensitive to the thermogenic effect of PGE(2) was unreactive to glutamate. Collectively, activation of neurons in the lateral POA and rostromedial POA evoked distinct thermoregulatory responses.
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Affiliation(s)
- T Osaka
- Department of Nutritional Science, National Institute of Health and Nutrition, 1-23-1 Toyama, Shinjuku 162-8636, Japan.
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343
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Talbot S, De Brito Gariépy H, Saint-Denis J, Couture R. Activation of kinin B1 receptor evokes hyperthermia through a vagal sensory mechanism in the rat. J Neuroinflammation 2012; 9:214. [PMID: 22971439 PMCID: PMC3460782 DOI: 10.1186/1742-2094-9-214] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2012] [Accepted: 08/27/2012] [Indexed: 12/25/2022] Open
Abstract
Background Kinins are mediators of pain and inflammation. Their role in thermoregulation is, however, unknown despite the fact the B1 receptor (B1R) was found implicated in lipopolysaccharide (LPS)-induced fever. The aim of this study was to investigate the mechanism by which peripheral B1R affects body core temperature in a rat model known to show up-regulated levels of B1R. Methods Male Sprague–Dawley rats received streptozotocin (STZ, 65 mg/kg; i.p.) to enhance B1R expression. Control rats received the vehicle only. One week later, rectal temperature was measured in awake rats after i.p. injection of increasing doses (0.01 to 5 mg/kg) of des-Arg9-Bradykinin (BK) and Sar-[D-Phe8]des-Arg9-BK (B1R agonists) or BK (B2R agonist). The mechanism of B1R-induced hyperthermia was addressed using specific inhibitors and in rats subjected to subdiaphragmatic vagal nerve ligation. B1R mRNA level was measured by quantitative Real Time-polymerase chain reaction (qRT-PCR) and B1R was localized by confocal microscopy. Results B1R agonists (0.1 to 5 mg/kg) showed transient (5- to 30-minute) and dose-dependent increases of rectal temperature (+1.5°C) in STZ-treated rats, but not in control rats. BK caused no effect in STZ and control rats. In STZ-treated rats, B1R agonist-induced hyperthermia was blocked by antagonists/inhibitors of B1R (SSR240612), cyclooxygenase-2 (COX-2) (niflumic acid) and nitric oxide synthase (NOS) (L-NAME), and after vagal nerve ligation. In contrast, COX-1 inhibition (indomethacin) had no effect on B1R agonist-induced hyperthermia. In STZ-treated rats, B1R mRNA was significantly increased in the hypothalamus and the vagus nerve where it was co-localized with calcitonin-gene-related peptide in sensory C-fibers. Conclusion B1R, which is induced in inflammatory diseases, could contribute to hyperthermia through a vagal sensory mechanism involving prostaglandins (via COX-2) and nitric oxide.
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Affiliation(s)
- Sébastien Talbot
- Department of Physiology, Faculty of Medicine, Université de Montréal, Montréal, QC H3C 3J7, Canada
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344
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Central hyperthermia, brain hyperthermia and low hypothalamus temperature. Clin Auton Res 2012; 22:299-301. [PMID: 22875550 DOI: 10.1007/s10286-012-0174-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Accepted: 07/09/2012] [Indexed: 01/27/2023]
Abstract
UNLABELLED INTRODUCTION, PATIENTS AND METHODS: We measured brain temperature in a case of central hyperthermia. RESULTS Brain temperature was increased except for hypothalamus that was colder. CONCLUSION We suppose that central hyperthermia is driven by cold hypothalamus.
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Abstract
The hypometabolic state of torpor is a widely utilized and well-orchestrated response to food shortage. A new study shows that the melatonin-related orphan receptor GPR50 plays an important function in metabolic regulation for entry into torpor.
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Affiliation(s)
- Steven J Swoap
- Department of Biology, Williams College, Williamstown, MA 01267, USA.
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346
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Saper CB, Romanovsky AA, Scammell TE. Neural circuitry engaged by prostaglandins during the sickness syndrome. Nat Neurosci 2012; 15:1088-95. [PMID: 22837039 DOI: 10.1038/nn.3159] [Citation(s) in RCA: 187] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
During illnesses caused by infectious disease or other sources of inflammation, a suite of brain-mediated responses called the sickness syndrome occurs, which includes fever, anorexia, sleepiness, hyperalgesia and elevated corticosteroid secretion. Much of the sickness syndrome is mediated by prostaglandins acting on the brain and can be prevented by nonsteroidal anti-inflammatory drugs, such as aspirin or ibuprofen, that block prostaglandin synthesis. By examining which prostaglandins are produced at which sites and how they interact with the nervous system, researchers have identified specific neural circuits that underlie the sickness syndrome.
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Affiliation(s)
- Clifford B Saper
- Department of Neurology, Harvard Medical School, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA.
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347
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Wallsten H, Olsson K, Dahlborn K. Temperature regulation in horses during exercise and recovery in a cool environment. Acta Vet Scand 2012; 54:42. [PMID: 22805591 PMCID: PMC3427134 DOI: 10.1186/1751-0147-54-42] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Accepted: 07/17/2012] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND Clipping the winter coat in horses is done to improve heat dissipation during exercise and make grooming easier. It is often combined with blanketing to keep the horse warm. The aims of the present study were to investigate how clipping and the use of blankets affect thermoregulation during exercise and recovery in horses. METHODS One Gotland pony, one New Forest pony, and one warm-blooded horse exercised one after the other on a 6450 m long track. The horses walked, trotted and cantered according to a predetermined scheme, which took about 50 minutes including three stops. The scheme was repeated on five consecutive days when horses were: 1) unclipped 2) unclipped + blanket during recovery, 3) left or right side clipped, 4) clipped, and 5) clipped + riding blanket + blanket during recovery. Heart rate (HR) was measured with telemetry, respiratory rate (RR) by counting flank contractions, skin temperatures by thermistor probes, and rectal temperature with a digital thermometer. Skin wetness (SW) was estimated by ocular inspection (dripping = 5, dry = 0). RESULTS Mean outdoor temperature varied from -1.1 to - 8.7°C. HR increased progressively during exercise with no difference between treatments. Maximum RR was 77 ± 30 breaths/min (unclipped) and 49 ± 27 breaths/min (clipped). The lowest skin temperature was 17.5 ± 2.7°C in a hind leg during exercise, which increased to 34.5 ± 0.1°C during recovery. Rectal temperature was elevated during recovery in unclipped, but not in clipped horses and skin temperature at base of tail was elevated during recovery except in unclipped horses without blanket. Moisture after exercise scored 3.2 ± 0.8 in unclipped and zero in clipped horses. DISCUSSION AND CONCLUSION Leg skin temperature initially dropped at onset of exercise in clipped horses, and then increased after about 30 minutes due to internal heat from the working muscles. These changes were not significant when clipped horses had riding blankets, whereas unclipped horses became overheated as judged from respiratory rate and elevated rectal temperature. Providing clipped horses with blankets dampened the changes in leg skin temperature during exercise.
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Affiliation(s)
- Hanna Wallsten
- Department of Anatomy, Physiology, and Biochemistry, Faculty of Veterinary Medicine and Animal Science, Swedish University of Agricultural Sciences, Box 7011, SE-750 07, Uppsala, Sweden
| | - Kerstin Olsson
- Department of Anatomy, Physiology, and Biochemistry, Faculty of Veterinary Medicine and Animal Science, Swedish University of Agricultural Sciences, Box 7011, SE-750 07, Uppsala, Sweden
| | - Kristina Dahlborn
- Department of Anatomy, Physiology, and Biochemistry, Faculty of Veterinary Medicine and Animal Science, Swedish University of Agricultural Sciences, Box 7011, SE-750 07, Uppsala, Sweden
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348
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Mallick HN, Kumar VM. Basal forebrain thermoregulatory mechanism modulates auto-regulated sleep. Front Neurol 2012; 3:102. [PMID: 22754548 PMCID: PMC3384086 DOI: 10.3389/fneur.2012.00102] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2012] [Accepted: 06/09/2012] [Indexed: 11/28/2022] Open
Abstract
Regulation of body temperature and sleep are two physiological mechanisms that are vital for our survival. Interestingly neural structures implicated in both these functions are common. These areas include the medial preoptic area (POA), the lateral POA, the ventrolateral POA, the median preoptic nucleus, and the medial septum, which form part of the basal forebrain (BF). When given a choice, rats prefer to stay at an ambient temperature of 27°C, though the maximum sleep was observed when they were placed at 30°C. Ambient temperature around 27°C should be considered as the thermoneutral temperature for rats in all sleep studies. At this temperature the diurnal oscillations of sleep and body temperature are properly expressed. The warm sensitive neurons of the POA mediate the increase in sleep at 30°C. Promotion of sleep during the rise in ambient temperature from 27 to 30°C, serve a thermoregulatory function. Autonomous thermoregulatory changes in core body temperature and skin temperature could act as an input signal to modulate neuronal activity in sleep-promoting brain areas. The studies presented here show that the neurons of the BF play a key role in regulating sleep. BF thermoregulatory system is a part of the global homeostatic sleep regulatory mechanism, which is auto-regulated.
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Affiliation(s)
- Hruda Nanda Mallick
- Department of Physiology, All India Institute of Medical Sciences New Delhi, India
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Affiliation(s)
- A. Bondke Persson
- Institute of Vegetative Physiology; Charité-Universitaetsmedizin; Berlin; Germany
| | - P. B. Persson
- Institute of Vegetative Physiology; Charité-Universitaetsmedizin; Berlin; Germany
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Richard D, Monge-Roffarello B, Chechi K, Labbé SM, Turcotte EE. Control and physiological determinants of sympathetically mediated brown adipose tissue thermogenesis. Front Endocrinol (Lausanne) 2012; 3:36. [PMID: 22654862 PMCID: PMC3356074 DOI: 10.3389/fendo.2012.00036] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2011] [Accepted: 02/13/2012] [Indexed: 02/05/2023] Open
Abstract
Brown adipose tissue (BAT) represents a remarkable heat-producing tissue. The thermogenic potential of BAT is conferred by uncoupling protein 1, a protein found uniquely in brown adipocytes. BAT activity and capacity is controlled by the sympathetic nervous system (SNS), which densely innervates brown fat depots. SNS-mediated BAT thermogenesis is essentially governed by hypothalamic and brainstem neurons. BAT activity is also modulated by brain energy balance pathways including the very significant brain melanocortin system, suggesting a genuine involvement of SNS-mediated BAT thermogenesis in energy homeostasis. The use of positron emission tomography/computed tomography scanning has revealed the presence of well-defined BAT depots in the cervical, clavicular, and paraspinal areas in adult humans. The prevalence of these depots is higher in subjects exposed to low temperature and is also higher in women compared to men. Moreover, the prevalence of BAT decreases with age and body fat mass, suggesting that BAT could be involved in energy balance regulation and obesity in humans. This short review summarizes recent progress made in our understanding of the control of SNS-mediated BAT thermogenesis and of the determinants of BAT prevalence or detection in humans.
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Affiliation(s)
- Denis Richard
- Centre de recherche de l’Institut universitaire de cardiologie et de pneumologie de Québec et Groupe interdisciplinaire de Recherche sur l’Obésité de l’Université LavalQuébec, QC, Canada
- *Correspondence: Denis Richard, Centre de recherche de l’Institut universitaire de cardiologie et de pneumologie de Québec, 2725 Chemin Sainte-Foy, Québec, QC, Canada G1V 4G5. e-mail:
| | - Boris Monge-Roffarello
- Centre de recherche de l’Institut universitaire de cardiologie et de pneumologie de Québec et Groupe interdisciplinaire de Recherche sur l’Obésité de l’Université LavalQuébec, QC, Canada
| | - Kanta Chechi
- Centre de recherche de l’Institut universitaire de cardiologie et de pneumologie de Québec et Groupe interdisciplinaire de Recherche sur l’Obésité de l’Université LavalQuébec, QC, Canada
| | - Sébastien M. Labbé
- Centre de recherche de l’Institut universitaire de cardiologie et de pneumologie de Québec et Groupe interdisciplinaire de Recherche sur l’Obésité de l’Université LavalQuébec, QC, Canada
| | - Eric E. Turcotte
- Centre de recherche de l’Institut universitaire de cardiologie et de pneumologie de Québec et Groupe interdisciplinaire de Recherche sur l’Obésité de l’Université LavalQuébec, QC, Canada
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