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Henrik SZŐKE, István BÓKKON, David M, Jan V, Ágnes K, Zoltán K, Ferenc F, Tibor K, László SL, Ádám D, Odilia M, Andrea K. The innate immune system and fever under redox control: A Narrative Review. Curr Med Chem 2022; 29:4324-4362. [DOI: 10.2174/0929867329666220203122239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2021] [Revised: 11/21/2021] [Accepted: 12/07/2021] [Indexed: 11/22/2022]
Abstract
ABSTRACT:
In living cells, redox potential is vitally important for normal physiological processes that are closely regulated by antioxidants, free amino acids and proteins that either have reactive oxygen and nitrogen species capture capability or can be compartmentalized. Although hundreds of experiments support the regulatory role of free radicals and their derivatives, several authors continue to claim that these perform only harmful and non-regulatory functions. In this paper we show that countless intracellular and extracellular signal pathways are directly or indirectly linked to regulated redox processes. We also briefly discuss how artificial oxidative stress can have important therapeutic potential and the possible negative effects of popular antioxidant supplements.
Next, we present the argument supported by a large number of studies that several major components of innate immunity, as well as fever, is also essentially associated with regulated redox processes. Our goal is to point out that the production of excess or unregulated free radicals and reactive species can be secondary processes due to the perturbed cellular signal pathways. However, researchers on pharmacology should consider the important role of redox mechanisms in the innate immune system and fever.
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Affiliation(s)
- SZŐKE Henrik
- Doctoral School of Health Sciences, University of Pécs, Pécs, Hungary
| | - BÓKKON István
- Neuroscience and Consciousness Research Department, Vision Research Institute,
Lowell, MA, USA
| | - martin David
- Department of Human Medicine, University Witten/Herdecke, Witten, Germany
| | - Vagedes Jan
- University Children’s Hospital, Tuebingen University, Tuebingen, Germany
| | - kiss Ágnes
- Doctoral School of Health Sciences, University of Pécs, Pécs, Hungary
| | - kovács Zoltán
- Doctoral School of Health Sciences, University of Pécs, Pécs, Hungary
| | - fekete Ferenc
- Department of Nyerges Gábor Pediatric Infectology, Heim Pál National Pediatric Institute, Budapest, Hungary
| | - kocsis Tibor
- Department of Clinical Governance, Hungarian National Ambulance Service, Budapest, Hungary
| | | | | | | | - kisbenedek Andrea
- Doctoral School of Health Sciences, University of Pécs, Pécs, Hungary
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N P, Ss A, Pv M. Comprehensive biology of antipyretic pathways. Cytokine 2019; 116:120-127. [PMID: 30711851 DOI: 10.1016/j.cyto.2019.01.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 01/09/2019] [Accepted: 01/11/2019] [Indexed: 01/10/2023]
Abstract
Pyrogens, the fever inducing substances accidently enter into a human body through contamination from medical or pharmaceutical products may create mild to severe complications including septicaemia and shocking syndromes. To avoid such drastic situations all the pharmaceuticals and medical devices are analysed for presence of pyrogens prior to their release into market. The entry of exogenous pyrogens like bacterial endotoxins induces the release of endogenous pyrogens or inflammatory cytokines that activate immune system to defend against these pathogens. Generation of heat is considered as one of the important defence mechanism of body achieved through receptor mediated interaction of endogenous pyrogens at the thermoregulatory centre of hypothalamus. However, uncontrolled fever and febrile reaction may cause lethal effects to the subject itself. So a well sophistically functioning antipyretic mechanism is necessary to achieve thermoregulation. The coordinated interaction of antipyretic cytokines and other mediators are active in human immune system which play a crucial role in maintaining thermal homeostasis. The multiple interacting antipyretic signals and their mechanism are the major subjects of this review.
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Affiliation(s)
- Prajitha N
- Toxicology Division, Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Poojapura, Trivandrum 695 012, Kerala, India
| | - Athira Ss
- Toxicology Division, Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Poojapura, Trivandrum 695 012, Kerala, India
| | - Mohanan Pv
- Toxicology Division, Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Poojapura, Trivandrum 695 012, Kerala, India.
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Wang H, Lu Z, Liu YH, Sun Y, Tu L, Ngan MP, Yeung CK, Rudd JA. Establishment of a radiotelemetric recording technique in mice to investigate gastric slow waves: Modulatory role of putative neurotransmitter systems. Exp Physiol 2018; 103:827-837. [PMID: 29667248 DOI: 10.1113/ep086815] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 04/16/2018] [Indexed: 12/16/2022]
Abstract
NEW FINDINGS What is the central question of this study? Gastric slow waves originating from the interstitial cells of Cajal-smooth muscle syncytium are usually studied in culture or in tissue segments, but nobody has described recordings of slow waves from awake, freely moving mice. Can radiotelemetry be used to record slow waves, and do they respond predictably to drug treatment? What is the main finding and its importance? Radiotelemetry can be used to record slow waves from awake, freely moving mice, permitting an examination of drug actions in vivo, which is crucial to drug discovery projects for characterizing the effects of drugs and metabolites on gastrointestinal function. ABSTRACT The mouse is the most commonly used species in preclinical research, and isolated tissues are used to study slow waves from the interstitial cells of Cajal-smooth muscle syncytium of the gastrointestinal tract. The aim of this study was to establish a radiotelemetric technique in awake mice to record gastric myoelectric activity from the antrum to gain insight into the effects of endogenous modulatory systems on slow waves. Under general anaesthesia, two biopotential wires from a telemetry transmitter were sutured into the antrum of male ICR (imprinting control region) mice. The animals were allowed 1 week to recover from surgery before the i.p. administration of drugs to stimulate or inhibit slow waves. The basal dominant frequency of slow waves was 6.96 ± 0.43 c.p.m., and the percentages of power in the bradygastric, normogastric and tachygastric ranges were 6.89 ± 0.98, 37.32 ± 1.72 and 34.38 ± 0.77%, respectively (n = 74). Nicotine at 1 mg kg-1 increased normogastric power, but at 3 mg kg-1 it increased bradygastric power (P < 0.05). Metoclopramide at 10 mg kg-1 increased normogastric power; sodium nitroprusside at 10 mg kg-1 had latent effects on tachygastric power (P < 0.05); and l-NAME at 10 mg kg-1 had no effect (P > 0.05). Nicotine and bethanechol also caused varying degrees of hypothermia (>1°C reductions; P < 0.05). In conclusion, radiotelemetry can be used to record slow waves from awake, freely moving mice. In light of our findings, we recommend that studies assessing slow waves should also assess body temperature simultaneously.
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Affiliation(s)
- Huichuan Wang
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, SAR, China
| | - Zengbing Lu
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, SAR, China
| | - Yuen Hang Liu
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, SAR, China
| | - Yayi Sun
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, SAR, China
| | - Longlong Tu
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, SAR, China
| | - Man P Ngan
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, SAR, China
| | - Chi-Kong Yeung
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, SAR, China
| | - John A Rudd
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, SAR, China.,Brain and Mind Institute, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, SAR, China
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BROŽÍČKOVÁ C, MIKULECKÁ A, OTÁHAL J. Effect of 7-Nitroindazole, a Neuronal Nitric Oxide Synthase Inhibitor, on Behavioral and Physiological Parameters. Physiol Res 2014; 63:637-48. [DOI: 10.33549/physiolres.932781] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
The role of brain derived nitric oxide in the physiology and behavior remains disputable. One of the reasons of the controversies might be systemic side effects of nitric oxide synthase inhibitors. Therefore, under nNOS inhibition by 7-nitroindazole (7-NI) we carried out recordings of blood gasses, blood pressure and spontaneous EEG in conscious adult rats. Locomotion and spontaneous behavior were assessed in an open field. In addition skilled walking and limb coordination were evaluated using a ladder rung walking test. The blood gas analysis revealed a significant increase in pCO2 180 min and 240 min after the application of 7-NI. The power and entropy decreased simultaneously with a shift of the mean frequency of the spontaneous EEG toward slow oscillations after 7-NI treatment. The thresholds of evoked potentials underwent a significant drop and a trend towards a slight increase in the I-O curve slope was observed. 7-NI significantly suppressed open field behavior expressed as distance moved, exploratory rearing and grooming. As for the ladder rung walking test the 7-NI treated animals had more errors in foot placement indicating impairment in limb coordination. Therefore our findings suggest that 7-NI increased cortical excitability and altered some physiological and behavioral parameters.
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Affiliation(s)
| | | | - J. OTÁHAL
- Department of Developmental Epileptology, Institute of Physiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
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Branco LG, Soriano RN, Steiner AA. Gaseous Mediators in Temperature Regulation. Compr Physiol 2014; 4:1301-38. [DOI: 10.1002/cphy.c130053] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Branco LGS, Bicego KC, Carnio EC, Pittman QJ. Gaseous neurotransmitters and their role in anapyrexia. Front Biosci (Elite Ed) 2010; 2:948-60. [PMID: 20515766 DOI: 10.2741/e154] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Mammals keep their body temperature (Tb) relatively constant even under a wide range of ambient temperature variation. However, in some particular situations it may be beneficial to increase or to decrease Tb. For instance, under hypoxic conditions, a regulated drop in Tb (anapyrexia) takes place which has been reported to be crucial for survival in a number of different species. This review highlights major advances in the research about nitric oxide (NO) and carbon monoxide (CO- where data are relatively less abundant), before focusing on the role played by these gaseous neuromediators in thermoregulation, under the conditions of euthermia and anapyrexia. Available data are consistent with the notion that both NO and CO, acting on the CNS, participate in thermoregulation, with NO decreasing Tb and CO increasing it. However further studies are required before definitive conclusions can be made as to their physiological mechanisms of action.
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Affiliation(s)
- Luiz G S Branco
- Dental School of Ribeirao Preto, University of Sao Paulo, Ribeirao Preto, Sao Paulo, Brazil.
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Sarkar S, Zaretskaia MV, Zaretsky DV, Moreno M, DiMicco JA. Stress- and lipopolysaccharide-induced c-fos expression and nNOS in hypothalamic neurons projecting to medullary raphe in rats: a triple immunofluorescent labeling study. Eur J Neurosci 2007; 26:2228-38. [PMID: 17927775 DOI: 10.1111/j.1460-9568.2007.05843.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Neurons in the rostral raphe pallidus (rRP) have been proposed to mediate experimental stress-induced tachycardia and fever in rats, and projections from the dorsomedial hypothalamus (DMH) may signal their activation in these settings. Thus, we examined c-fos expression evoked by air jet/restraint stress and restraint stress or by systemic administration of lipopolysaccharide (10 microg/kg and 100 microg/kg) as well as the distribution of the neuronal nitric oxide synthase (nNOS) in neurons retrogradely labeled from the raphe with cholera toxin B in key hypothalamic regions. Many neurons in the medial preoptic area and the dorsal area of the DMH were retrogradely labeled, and approximately half of those in the medial preoptic area and moderate numbers in the dorsal DMH were also positive for nNOS. Either stress paradigm or dose of lipopolysaccharide increased the number of c-fos-positive neurons and nNOS/c-fos double-labeled neurons in all regions examined. However, retrogradely labeled neurons positive for c-fos were increased only in the dorsal DMH and adjoining region in both stressed and lipopolysaccharide-treated groups, and triple-labeled neurons were found only in this area in rats subjected to either stress paradigm. Thus, hypothalamic neurons that project to the rRP and express c-fos in response to either experimental stress or systemic inflammation are found only in the dorsal DMH, and many of those activated by stress contain nNOS, suggesting that nitric oxide may play a role in signaling in this pathway.
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Affiliation(s)
- Sumit Sarkar
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, 635 Barnhill Dr, Indianapolis, IN 46202, USA
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Lacerda ACR, Marubayashi U, Coimbra CC. Nitric oxide pathway is an important modulator of heat loss in rats during exercise. Brain Res Bull 2005; 67:110-6. [PMID: 16140169 DOI: 10.1016/j.brainresbull.2005.06.002] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2005] [Accepted: 06/03/2005] [Indexed: 11/24/2022]
Abstract
To assess the role of nitric oxide (NO) in central thermoregulatory mechanisms during exercise, 1.43 micromol (2 microL) of N(omega)-nitro-L-arginine methyl ester (L-NAME, n=6), a NO synthase inhibitor, or 2 microL of 0.15M NaCl (SAL, n=6) was injected into the lateral cerebral ventricle of male Wistar rats immediately before the animals started running (18 m min(-1), 5% inclination). Core (Tb) and skin tail (Ttail) temperatures were measured. Body heating rate (BHR), threshold Tb for tail vasodilation (TTbV), and workload (W) were calculated. During the first 11 min of exercise, there was a greater increase in Tb in the L-NAME group than in the SAL group (BRH=0.17+/-0.02 degrees C min(-1), L-NAME, versus 0.09+/-0.01 degrees C min(-1), SAL, p<0.05). Following the first 11 min until approximately 40 min of exercise, Tb levels remained stable in both groups, but levels remained higher in the L-NAME group than in the SAL group (39.16+/-0.04 degrees C, L-NAME, versus 38.33+/-0.02 degrees C, SAL, p<0.01). However, exercise went on to induce an additional rise in Tb in the SAL group prior to fatigue. These results suggest that the reduced W observed in L-NAME-treated rats (10.8+/-2.0 kg m, L-NAME, versus 25.0+/-2.1 kg m, SAL, p<0.01) was related to the increased BHR in L-NAME-treated animals observed during the first 11 min of exercise (r=0.74, p<0.01) due to the change in TTbV (39.12+/-0.24 degrees C, L-NAME, versus 38.27+/-0.10 degrees C, SAL, p<0.05). Finally, our data suggest that the central nitric oxide pathway modulates mechanisms of heat dissipation during exercise through an inhibitory mechanism.
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Affiliation(s)
- Ana Cristina R Lacerda
- Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais, 31270-901 Belo Horizonte, Minas Gerais, Brazil
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Steiner AA, Rudaya AY, Ivanov AI, Romanovsky AA. Febrigenic signaling to the brain does not involve nitric oxide. Br J Pharmacol 2004; 141:1204-13. [PMID: 15006900 PMCID: PMC1574882 DOI: 10.1038/sj.bjp.0705713] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2003] [Revised: 01/19/2004] [Accepted: 01/23/2004] [Indexed: 01/01/2023] Open
Abstract
1. The involvement of peripheral nitric oxide (NO) in febrigenic signaling to the brain has been proposed because peripherally administered NO synthase (NOS) inhibitors attenuate lipopolysaccharide (LPS)-induced fever in rodents. However, how the unstable molecule of NO can reach the brain to trigger fever is unclear. It is also unclear whether NOS inhibitors attenuate fever by blocking febrigenic signaling or, alternatively, by suppressing thermogenesis in brown fat. 2. Male Wistar rats were chronically implanted with jugular catheters; their colonic and tail skin temperatures (T(c) and T(sk)) were monitored. 3. Study 1 was designed to determine whether the relatively stable, physiologically relevant forms of NO, that is, S-nitrosoalbumin (SNA) and S-nitrosoglutathione (SNG), are pyrogenic and whether they enhance LPS fever. At a neutral ambient temperature (T(a)) of 31 degrees C, afebrile or LPS (1 microg kg(-1), i.v.)-treated rats were infused i.v. with SNA (0.34 or 4.1 micromol kg(-1); the controls received NaNO(2) and albumin) or SNG (10 or 60 micromol kg(-1); the controls received glutathione). T(c) of SNA- or SNG-treated rats never exceeded that of the controls. 4. In Study 2, we tested whether the known fever-attenuating effect of the NOS inhibitor N(omega)-nitro-L-arginine methyl ester (L-NAME) at a subneutral T(a) (when fever is brought about by thermogenesis) also occurs at a neutral T(a) (when fever is brought about by skin vasoconstriction). At a subneutral T(a) of 24 degrees C, L-NAME (2.5 mg kg(-1), i.v.) attenuated LPS (10 microg kg(-1), i.v.) fever, presumably by inhibiting thermogenesis. At 31 degrees C, L-NAME enhanced LPS fever by augmenting skin vasoconstriction (T(sk) fall). 5. In summary, both SNA and SNG had no pyrogenic effect of their own and failed to enhance LPS fever; peripheral L-NAME attenuated only fever brought about by increased thermogenesis. It is concluded that NO is uninvolved in febrigenic signaling to the brain.
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Affiliation(s)
- Alexandre A Steiner
- Systemic Inflammation Laboratory, Trauma Research, St Joseph's Hospital and Medical Center, 350 W. Thomas Rd., Phoenix, AZ 85013, U.S.A
| | - Alla Y Rudaya
- Systemic Inflammation Laboratory, Trauma Research, St Joseph's Hospital and Medical Center, 350 W. Thomas Rd., Phoenix, AZ 85013, U.S.A
| | - Andrei I Ivanov
- Systemic Inflammation Laboratory, Trauma Research, St Joseph's Hospital and Medical Center, 350 W. Thomas Rd., Phoenix, AZ 85013, U.S.A
| | - Andrej A Romanovsky
- Systemic Inflammation Laboratory, Trauma Research, St Joseph's Hospital and Medical Center, 350 W. Thomas Rd., Phoenix, AZ 85013, U.S.A
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Benamar K, Yondorf MZ, Kon D, Geller EB, Adler MW. Role of the nitric-oxide synthase isoforms during morphine-induced hyperthermia in rats. J Pharmacol Exp Ther 2003; 307:219-22. [PMID: 12954818 DOI: 10.1124/jpet.103.053181] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Recently, we demonstrated that the diffusible messenger molecule nitric oxide (NO) is involved in the hyperthermic response induced by morphine by using a nonselective nitric-oxide synthase inhibitor, N-nitro-L-arginine methyl ester. The present work extended these studies to include 7-nitroindazole (7-NI), an inhibitor specific for neuronal nitric-oxide synthase (nNOS), N(5)-(-iminoethyl)-L-ornithine (L-NIO), an inhibitor of endothelial NOS (eNOS), and aminoguanidine (AG), a potent inhibitor of inducible NOS (iNOS). A biotelemetry system was used in this study to measure the body temperature (Tb). A dose of 7-NI (5 or 10 mg/kg), which did not affect Tb by itself, blocked the hyperthermia induced by morphine in a dose-dependent manner (15 mg/kg i.p.). However, pretreatment with L-NIO (10-20 mg/kg) or with AG (50 mg/kg) failed to alter the hyperthermia induced by morphine. L-NIO (10-20 mg/kg) or AG (50 mg/kg) had no effect on Tb. These results suggest the involvement of nNOS in morphine-induced hyperthermia.
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Affiliation(s)
- Khalid Benamar
- Center for Substance Abuse Research, Department of Pharmacology, Temple University School of Medicine, Philadelphia, PA 19140, USA.
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Kozak W, Kozak A. Genetic Models in Applied Physiology. Differential role of nitric oxide synthase isoforms in fever of different etiologies: studies using Nos gene-deficient mice. J Appl Physiol (1985) 2003; 94:2534-44. [PMID: 12562678 DOI: 10.1152/japplphysiol.01042.2002] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Male C57BL/6J mice deficient in nitric oxide synthase (NOS) genes (knockout) and control (wild-type) mice were implanted intra-abdominally with battery-operated miniature biotelemeters (model VMFH MiniMitter, Sunriver, OR) to monitor changes in body temperature. Intravenous injection of lipopolysaccharide (LPS; 50 microg/kg) was used to trigger fever in response to systemic inflammation in mice. To induce a febrile response to localized inflammation, the mice were injected subcutaneously with pure turpentine oil (30 microl/animal) into the left hindlimb. Oral administration (gavage) of N(G)-monomethyl-l-arginine (l-NMMA) for 3 days (80 mg. kg(-1). day(-1) in corn oil) before injection of pyrogens was used to inhibit all three NOSs (N(G)-monomethyl-d-arginine acetate salt and corn oil were used as control). In normal male C57BL/6J mice, l-NMMA inhibited the LPS-induced fever by approximately 60%, whereas it augmented fever by approximately 65% in mice injected with turpentine. Challenging the respective NOS knockout mice with LPS and with l-NMMA revealed that inducible NOS and neuronal NOS isoforms are responsible for the induction of fever to LPS, whereas endothelial NOS (eNOS) is not involved. In contrast, none of the NOS isoforms appeared to trigger fever to turpentine. Inhibition of eNOS, however, exacerbates fever in mice treated with l-NMMA and turpentine, indicating that eNOS participates in the antipyretic mechanism. These data support the hypothesis that nitric oxide is a regulator of fever. Its action differs, however, depending on the pyrogen used and the NOS isoform.
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Affiliation(s)
- Wieslaw Kozak
- Department of Physiology, Medical College of Georgia, Augusta, Georgia 30912, USA.
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Steiner AA, Antunes-Rodrigues J, McCann SM, Branco LGS. Antipyretic role of the NO-cGMP pathway in the anteroventral preoptic region of the rat brain. Am J Physiol Regul Integr Comp Physiol 2002; 282:R584-93. [PMID: 11792670 DOI: 10.1152/ajpregu.00391.2001] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We tested the hypothesis that nitric oxide (NO) acts in the anteroventral preoptic region (AVPO) modulating fever. To this end, body core temperature (T(c)) of rats was monitored by biotelemetry before and after pharmacological modulation of the NO pathway. Nitrite/nitrate and cGMP in the anteroventral third ventricular region (AV3V), where the AVPO is located, were also determined. Intra-AVPO microinjection of the NO synthase (NOS) inhibitor N(G)-monomethyl-L-arginine (L-NMMA, 12.5 microg) did not affect basal T(c), but it enhanced the early stage of lipopolysaccharide (LPS) fever, indicating that NO plays an antipyretic role in the AVPO. In agreement, intra-AVPO microinjection of the NO donor sodium nitroprusside (5 microg) reduced T(c). The antipyretic effect of NO seems to be mediated by cGMP because 1) NO has been shown to activate soluble guanylate cyclase, 2) intra-AVPO microinjection of 8-bromo-cGMP (8-BrcGMP) reduced T(c), and 3) the changes in AV3V levels of nitrite/nitrate and cGMP were similar in the course of fever. Additionally, we observed that nitrite/nitrate and cGMP levels decreased in the AV3V after, but not before, the onset of LPS fever, showing that the activity of the NO-cGMP pathway is reduced in the AV3V after intraperitoneal LPS, a mechanism that could contribute to the genesis and maintenance of fever. It was also observed that the efficacy of 8-BrcGMP in reducing T(c) in the AVPO is increased after LPS, emphasizing that the NO-cGMP pathway is antipyretic. This response could explain why intra-AVPO L-NMMA enhanced the early stage of LPS fever, even though the activity of the NO pathway before the onset of fever was unchanged. In summary, these data support an antipyretic role of the NO-cGMP pathway in the AVPO.
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Affiliation(s)
- Alexandre A Steiner
- Departamento de Fisiologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, 14040 - 904 Ribeirão Preto, São Paulo, Brazil
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Sanches DB, Steiner AA, Branco LGS. Involvement of neuronal nitric oxide synthase in restraint stress-induced fever in rats. Physiol Behav 2002; 75:261-6. [PMID: 11890976 DOI: 10.1016/s0031-9384(01)00657-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Nitric oxide (NO) has been shown to be an important modulator of the febrile response to pyrogens and to psychological stress. In the present study, we aimed to identify the nitric oxide synthase (NOS) isoform (neuronal or inducible, nNOS and iNOS, respectively) involved in restraint stress fever. Colonic temperature (Tc) was measured in unanesthetized rats before and after treatment with the more selective nNOS inhibitor 7-nitroindazole or with the selective iNOS inhibitor aminoguanidine (AG) under unrestrained or restrained conditions. Intraperitoneal injection of AG (25 or 50 mg/kg) did not affect restraint fever, indicating that iNOS is unlikely to be involved in restraint fever. On the other hand, intraperitoneal injection of 7-nitroindazole (25 mg/kg) significantly attenuated the rise in the Tc caused by restraint stress, whereas it caused no change in Tc of euthermic animals. These data show that NO produced by nNOS plays an important role in the genesis of restraint stress-induced fever.
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Affiliation(s)
- Daniela B Sanches
- Department of Morphology, Estomatology, and Physiology, Dental School of Ribeirão Preto, University of São Paulo, 14040 904 Ribeirão Preto, SP, Brazil
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Canini F, Buguet A, Bourdon L. Inhibition of different types of nitric oxide synthase: effect on thermoregulation in the rat exposed to high ambient temperature. Neurosci Lett 2001; 316:45-9. [PMID: 11720775 DOI: 10.1016/s0304-3940(01)02335-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Vascular and immunological mechanisms are both likely to be involved in heatstroke, this condition being preceded by a decrease in cerebral blood flow and an increase in brain cytokine concentrations. As the two mechanisms involve a nitridergic step, we analysed their respective role in heat tolerance by exposing vigil rats to heat after treatment with nitric oxide synthases (NOS) antagonists: non-specific inhibitors N(omega)-nitro-L-arginine (LNA) and N-nitro-L-arginine-methyl-ester (L-NAME); 7-nitroindazol (neuronal NOS inhibitor) and aminoguanidine (AG) (inducible NOS inhibitor). Heat exposure was interrupted when clinical signs occurred or when colonic temperature reached 43 degrees C. LNA and L-NAME dramatically reduced heat tolerance, while AG did not modify it. These results suggest the involvement of constitutive NOS in heat tolerance. Inducible NOS does not seem to be involved in the occurrence of heatstroke.
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Affiliation(s)
- F Canini
- Département des facteurs humains, Centre de recherches du Service de santé des armées (CRSSA), 24 av. des Maquis du Grésivaudan, BP 87, F-38702, Cédex, La Tronche, France.
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