Inhibition of nitric oxide synthase produces hypothermia and depresses lipopolysaccharide fever

1996 ◽  
Vol 271 (2) ◽  
pp. R333-R338 ◽  
Author(s):  
T. E. Scammell ◽  
J. K. Elmquist ◽  
C. B. Saper
Keyword(s):  
Nitric Oxide ◽  
Low Dose ◽  
Dependent Manner ◽  
Febrile Response ◽  
Bolus Intravenous Injection ◽  
Nos Inhibitor ◽  
Oxide Synthase ◽  
Dose Dependent ◽  
Higher Doses

The labile gas nitric oxide (NO) mediates a wide variety of thermoregulatory processes including vasomotor control, brown fat thermogenesis, and neuroendocrine regulation. Additionally, during endotoxemia, NO modulates the release of cytokines and hypothalamic peptides. To determine the role of NO in thermoregulation and fever, we intravenously injected the NO synthase (NOS) inhibitor NG-nitro-L-arginine methyl ester (L-NAME) and measured its effects on body temperature during normal thermoregulation and endotoxemia in awake, unrestrained rats. L-NAME produced a stereoselective, dose-dependent hypothermia that lasted up to 4 h after bolus intravenous injection. Intravenous lipopolysaccharide (LPS) produced fever in a dose-dependent manner, which was preceded by hypothermia at higher doses alpha-LPS. NOS inhibition reduced the febrile response to LPS and produced marked hypothermia with a low dose of LPS. These findings indicate that NO may play an important role in thermoregulation and suggest that NO is required for the production of fever.

scholarly journals A Role of Fluoride on Free Radical Generation and Oxidative Stress in BV-2 Microglia Cells

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Xi Shuhua ◽  
Liu Ziyou ◽  
Yan Ling ◽  
Wang Fei ◽  
Guifan Sun
Keyword(s):  
Oxidative Stress ◽  
Nitric Oxide ◽  
Dependent Manner ◽  
Microglia Cell ◽  
The Central Nervous System ◽  
Radical Generation ◽  
Oxide Synthase ◽  
Cell Medium ◽  
Dose Dependent

The generation of ROS and lipid peroxidation has been considered to play an important role in the pathogenesis of chronic fluoride toxicity. In the present study, we observed that fluoride activated BV-2 microglia cell line by observing OX-42 expression in immunocytochemistry. Intracellular superoxide dismutase (SOD), glutathione (GSH), malondialdehyde (MDA), reactive oxygen species (ROS), superoxide anions (O2∙-), nitric oxide synthase (NOS), nitrotyrosine (NT) and nitric oxide (NO), NOS in cell medium were determined for oxidative stress assessment. Our study found that NaF of concentration from 5 to 20 mg/L can stimuli BV-2 cells to change into activated microglia displaying upregulated OX-42 expression. SOD activities significantly decreased in fluoride-treated BV-2 cells as compared with control, and MDA concentrations and contents of ROS andO2∙-increased in NaF-treated cells. Activities of NOS in cells and medium significantly increased with fluoride concentrations in a dose-dependent manner. NT concentrations also increased significantly in 10 and 50 mg/L NaF-treated cells compared with the control cells. Our present study demonstrated that toxic effects of fluoride on the central nervous system possibly partly ascribed to activiting of microglia, which enhanced oxidative stress induced by ROS and reactive nitrogen species.

Dose-dependent effects of nitric oxide synthase inhibition on systemic and renal hemodynamics in conscious lambs

1999 ◽  
Vol 77 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Alp Sener ◽  
Francine G Smith
Keyword(s):  
Nitric Oxide ◽  
Methyl Ester ◽  
Vascular Resistance ◽  
Renal Hemodynamics ◽  
Renal Vascular Resistance ◽  
Dependent Manner ◽  
Oxide Synthase ◽  
Renal Vascular ◽  
Dose Dependent

The present experiments were carried out to determine the role of nitric oxide in influencing systemic and renal hemodynamics in conscious young sheep. Parameters of cardiovascular function were measured before and for 4 h after intravenous injection of either L-NAME (NG-nitro-L-arginine methyl ester) or D-NAME (NG-nitro-D-arginine methyl ester) at doses of 10, 20, or 40 mg/kg in 13 conscious, chronically instrumented young sheep aged 43 ± 5 days. Blood pressure increased and heart rate decreased in a dose-dependent manner following administration of L-NAME. Renal vascular resistance was increased for 10 min following a dose of 10 mg/kg of L-NAME and for 120 min following a dose of 40 mg/kg of L-NAME. The renal vasodilatory response to close arterial injection of 1 µg/kg of acetylcholine was attenuated by L-NAME in a dose-dependent manner. These experiments provide the first information that under normal physiological conditions in conscious young animals, nitric oxide influences systemic and renal hemodynamics.Key words: renal vascular resistance, renal blood flow, maturation, sheep, vascular tone, nitric oxide, endothelial-derived relaxing factor, L-NAME (NG-nitro-L-arginine methyl ester).

Role of ANG II in hypertension produced by chronic inhibition of nitric oxide synthase in conscious rats

1996 ◽  
Vol 271 (2) ◽  
pp. H806-H811 ◽  
Author(s):  
M. G. Melaragno ◽  
G. D. Fink
Keyword(s):  
Nitric Oxide ◽  
Time Course ◽  
Low Dose ◽  
Pressor Effect ◽  
Ang Ii ◽  
At1 Receptors ◽  
Nos Inhibitor ◽  
Oxide Synthase ◽  
Delayed Time

These experiments tested the hypothesis that hypertension caused by chronic inhibition of nitiric oxide synthase (NOS) is associated with augmented pressor responsiveness to angiotensin II (ANG II). Antagonism of ANG II AT1 receptors with losartan caused a greater fall in blood pressure (BP) in rats treated for 2 wk with the NOS inhibitor N omega-nitro-L-arginine methyl ester (L-NAME) than in normotensive rats. The delayed time course of the decline in BP implicated the slow pressor effect (SPE) of ANG II in L-NAME hypertension. Further experiments showed that direct elicitation of the SPE by continuous low-dose (4 ng/min) intravenous infusion of ANG II in enalapril-treated rats resulted in a larger chronic increase in BP if NOS was inhibited. However, L-NAME alone also caused a significant increase in BP in enalapril-treated rats. The combined effect on BP of ANG II and L-NAME was merely additive. These results confirm that ANG II is involved in L-NAME hypertension. However, chronic pressor responsiveness to the peptide is not augmented by L-NAME.

Suppressive effects of sulfated polysaccharide ascophyllan isolated from Ascophyllum nodosum on the production of NO and ROS in LPS-stimulated RAW264.7 cells

2020 ◽  
Vol 85 (4) ◽  
pp. 882-889
Author(s):  
Yan Liang ◽  
Shijiao Zha ◽  
Masanobu Tentaku ◽  
Takasi Okimura ◽  
Zedong Jiang ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Ascophyllum Nodosum ◽  
Sulfated Polysaccharide ◽  
Intracellular Reactive Oxygen Species ◽  
Raw264.7 Cells ◽  
Dependent Manner ◽  
Oxygen Species ◽  
Oxide Synthase ◽  
Dose Dependent ◽  
Inducible Nitric Oxide

ABSTRACT In this study, we found that a sulfated polysaccharide isolated from the brown alga Ascophyllum nodosum, ascophyllan, showed suppressive effects on stimulated RAW264.7 cells. Ascophyllan significantly inhibited expression of inducible nitric oxide synthase mRNA and excessive production of nitric oxide (NO) in lipopolysaccharide (LPS)-stimulated RAW264.7 cells in a dose-dependent manner without affecting the viability of RAW264.7 cells. Ascophyllan also reduced the elevated level of intracellular reactive oxygen species (ROS) in LPS-stimulated RAW264.7 cells. Furthermore, preincubation with ascophyllan resulted in concentration-dependent decrease in ROS production in phorbol 12-myristate-13-acetate-stimulated RAW264.7 cells. Our results suggest that ascophyllan can exhibit anti-inflammatory effects on stimulated macrophages mainly through the attenuation of NO and ROS productions.

Selective iNOS Inhibition Attenuates Acetylcholine- and Bradykinin-induced Vasoconstriction in Lipopolysaccharide-exposed Rat Lungs 

1999 ◽  
Vol 91 (6) ◽  
pp. 1724-1724 ◽  
Author(s):  
Lars G. Fischer ◽  
Damian J. Horstman ◽  
Klaus Hahnenkamp ◽  
Nancy E. Kechner ◽  
George F. Rich
Keyword(s):  
Nitric Oxide ◽  
Exhaled Nitric Oxide ◽  
Control Group ◽  
Biochemical Engineering ◽  
Inos Inhibitor ◽  
Nos Inhibitor ◽  
Inos Inhibitors ◽  
Oxide Synthase ◽  
Inos Inhibition ◽  
Dose Dependent

Background Nonselective nitric oxide synthase (NOS) inhibition has detrimental effects in sepsis because of inhibition of the physiologically important endothelial NOS (eNOS). The authors hypothesized that selective inducible NOS (iNOS) inhibition would maintain eNOS vasodilation but prevent acetylcholine- and bradykinin-mediated vasoconstriction caused by lipopolysaccharide-induced endothelial dysfunction. Methods Rats were administered intraperitoneal lipopolysaccharide (15 mg/kg) with and without the selective iNOS inhibitors L-N6-(1-iminoethyl)-lysine (L-NIL, 3 mg/kg), dexamethasone (1 mg/kg), or the nonselective NOS inhibitor Nomega-nitro-L-arginine methylester (L-NAME, 5 mg/kg). Six hours later, the lungs were isolated and pulmonary vasoreactivity was assessed with hypoxic vasoconstrictions (3% O2), acetylcholine (1 microg), Biochemical Engineering, and bradykinin (3 microg). In additional lipopolysaccharide experiments, L-NIL (10 microM) or 4-Diphenylacetoxy-N-methylpiperidine methiodide (4-DAMP, 100 microM), a selective muscarinic M3 antagonist, was added into the perfusate. Results Exhaled nitric oxide was higher in the lipopolysaccharide group (37.7+/-17.8 ppb) compared with the control group (0.4+/-0.7 ppb). L-NIL and dexamethasone decreased exhaled nitric oxide in lipopolysaccharide rats by 83 and 79%, respectively, whereas L-NAME had no effect. In control lungs, L-NAME significantly decreased acetylcholine- and bradykinin-induced vasodilation by 75% and increased hypoxic vasoconstrictions, whereas L-NIL and dexamethasone had no effect. In lipopolysaccharide lungs, acetylcholine and bradykinin both transiently increased the pulmonary artery pressure by 8.4+/-2.0 mmHg and 35.3+/-11.7 mmHg, respectively, immediately after vasodilation. L-NIL and dexamethasone both attenuated this vasoconstriction by 70%, whereas L-NAME did not. The acetylcholine vasoconstriction was dose-dependent (0.01-1.0 microg), unaffected by L-NIL added to the perfusate, and abolished by 4-DAMP. Conclusions In isolated perfused lungs, acetylcholine and bradykinin caused vasoconstriction in lipopolysaccharide-treated rats. This vasoconstriction was attenuated by administration of the iNOS inhibitor L-NIL but not with L-NAME. Furthermore, L-NIL administered with lipopolysaccharide preserved endothelium nitric oxide-dependent vasodilation, whereas L-NAME did not.

Role of Nitric Oxide towards Vasodilator Effects of Substance P and ATP in Human Forearm Vessels

1997 ◽  
Vol 92 (2) ◽  
pp. 123-131 ◽  
Author(s):  
Masanari Shiramoto ◽  
Tsutomu Imaizumi ◽  
Yoshitaka Hirooka ◽  
Toyonari Endo ◽  
Takashi Namba ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Blood Flow ◽  
Substance P ◽  
Sodium Nitroprusside ◽  
Forearm Blood Flow ◽  
Dependent Manner ◽  
Human Forearm ◽  
Before And After ◽  
Dose Dependent

1. It has been shown in animals that substance P as well as acetylcholine releases endothelium-derived nitric oxide and evokes vasodilatation and that ATP-induced vasodilatation is partially mediated by nitric oxide. The aim of this study was to examine whether vasodilator effects of substance P and ATP are mediated by nitric oxide in humans. 2. In healthy volunteers (n = 35), we measured forearm blood flow by a strain-gauge plethysmograph while infusing graded doses of acetylcholine, substance P, ATP or sodium nitroprusside into the brachial artery before and after infusion of NG-monomethyl-l-arginine (4 or 8 μmol/min for 5 min). In addition, we measured forearm blood flow while infusing substance P before and during infusion of l-arginine (10 mg/min, simultaneously), or before and 1 h after oral administration of indomethacin (75 mg). 3. Acetylcholine, substance P, ATP or sodium nitroprusside increased forearm blood flow in a dose-dependent manner. NG-Monomethyl-l-arginine decreased basal forearm blood flow and inhibited acetylcholine-induced vasodilatation but did not affect substance P-, ATP-, or sodium nitroprusside-induced vasodilatation. Neither supplementation of l-arginine nor pretreatment with indomethacin affected substance P-induced vasodilatation. 4. Our results suggest that, in the human forearm vessels, substance P-induced vasodilatation may not be mediated by either nitric oxide or prostaglandins and that ATP-induced vasodilatation may also not be mediated by nitric oxide.

Parasite killing in murine malaria does not require nitric oxide production

Parasitology ◽  
1999 ◽  
Vol 118 (2) ◽  
pp. 139-143 ◽  
Author(s):  
N. FAVRE ◽  
B. RYFFEL ◽  
W. RUDIN
Keyword(s):  
Nitric Oxide ◽  
Blood Stage ◽  
No Production ◽  
Nos Inhibitor ◽  
Oxide Synthase ◽  
Deficient Mice ◽  
Stage Parasite ◽  
Blood Stage Malaria ◽  
Inducible Nitric Oxide

Nitric oxide (NO) production has been suggested to play a role as effector molecule in the control of the malarial infections. However, the roles of this molecule are debated. To assess whether blood-stage parasite killing is NO dependent, we investigated the course of blood-stage Plasmodium chabaudi chabaudi (Pcc) infections in inducible nitric oxide synthase (iNOS)-deficient mice. Parasitaemia, haematological alterations, and survival were not affected by the lack of iNOS. To exclude a role of NO produced by other NOS, controls included NO suppression by oral administration of aminoguanidine (AG), a NOS inhibitor. As in iNOS-deficient mice, no difference in the parasitaemia course, survival and haematological values was observed after AG treatment. Our results indicate that NO production is not required for protection against malaria in our murine experimental model. However, C57BL/6 mice treated with AG lost their resistance to Pcc infections, suggesting that the requirement for NO production for parasite killing in murine blood-stage malaria might be strain dependent.

scholarly journals 108 THE ROLE OF NITRIC OXIDE SYNTHASE IN IN VITRO DEVELOPMENT OF BOVINE OOCYTES AND PRE-IMPLANTATION EMBRYOS

2005 ◽  
Vol 17 (2) ◽  
pp. 204
Author(s):  
A.K. Kadanga ◽  
D. Tesfaye ◽  
S. Ponsuksili ◽  
K. Wimmers ◽  
M. Gilles ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Culture Medium ◽  
Bovine Embryos ◽  
Nos Inhibitor ◽  
Blastocyst Rate ◽  
Oxide Synthase ◽  
Vitro Development ◽  
Bovine Oocytes

Nitric oxide (NO) is a free radical that serves as a key-signal molecule in various physiological processes including reproduction. Four isoforms of nitric oxide synthase (NOS) have been characterized: endothelial (eNOS), inducible (iNOS), neuronal (nNOS), and mitochondrial (mtNOS). The first two isoforms are reported to be expressed in mouse follicles, oocytes, and pre-implantation embryos (Nishikimi A et al. 2001 Reproduction 122, 957–963). However, the role of any of these isoforms have not yet been investigated in bovine embryos. Here we aimed to examine the role of NOS in in vitro development of bovine embryos by treating embryos with NOS inhibitor, N-omega-L-nitro-arginine methyl esther (L-NAME), and examining the localization of the protein in pre-implantation embryos. Oocytes and embryos were grown in the media with NOS inhibitor added at a level of 0 mM (control), 1 mM, and 10 mM to either maturation or culture medium. Each experiment was conducted in four replicates each containing 100 oocytes for IVP. Cleavage and blastocyst rate were recorded at Days 2 and 7, respectively. Data were analyzed using the General Linear Model in SAS version 8.02 (SAS Institute, Inc., Cary, NC, USA) with the main factors being the level of L-NAME and the point of application. Pairwise comparisons were done using the Tukey test. Protein localization in bovine oocytes and embryos was performed by immunocytochemistry using eNOS- and iNOS-specific antibodies. Embryos were fixed in 3.7% paraformaldehyde, permeabilized in 0.1% Triton-X100, and washed three times in PBS supplemented with BSA. They were incubated with eNOS and iNOS primary antibody (1:200 dilutions) and washed before incubation with secondary antibody conjugated to FITC. After washing they were mounted on glass slides and examined under a confocal laser scanning microscope (Carl Zeiss Jena, Carl Zeiss AG, Oberkochen, Germany). In the controls the primary antibodies were omitted. As shown in the table below, the presence of L-NAME in the maturation medium significantly reduced the cleavage and blastocyst rate independent of the dosage applied. However the presence of L-NAME in the culture medium had an influence only on the blastocyst rate. The immunocytochemical staining results showed that both eNOS and iNOS are expressed in the cytoplasm of the MII oocytes, and during the pre-implantation stage the fluorescence signal was observed in nuclei and cytoplasm. However, the nuclear signal was much weaker. In conclusion, the present study is the first to determine the role of NO and to detect NOS protein in bovine oocytes and pre-implantation embryos. These results indicate that nitric oxide may play an important role as diffusible regulator of bovine oocyte maturation and preimplantation embryo development. Table 1. Effect of l-name addition in maturation or culture medium on embryo development

PKC mediates LPS- and phorbol-induced cardiac cell nitric oxide synthase activity and hypocontractility

1995 ◽  
Vol 269 (6) ◽  
pp. H1891-H1898 ◽  
Author(s):  
T. M. McKenna ◽  
S. Li ◽  
S. Tao
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Cardiac Myocyte ◽  
Contractile Function ◽  
Dependent Manner ◽  
Cardiac Cell ◽  
Nos Inhibitor ◽  
Oxide Synthase ◽  
Myocyte Contractility ◽  
Rat Cardiac Myocytes

Lipopolysaccharide (LPS) treatment impairs cardiac myocyte contractility in a nitric oxide synthase (NOS)-dependent manner. The objective of this study was to assess whether protein kinase C (PKC) transduces the LPS signal into an enhanced NOS activity in rat cardiac myocytes. LPS (100 ng/ml) stimulated myocyte PKC activity, inducible NOS (iNOS) expression, and NOS activity in a time- and protein synthesis-dependent fashion. Directly activating PKC with beta-phorbol 12,13-dibutyrate (beta-PDB) also induced myocyte iNOS synthesis and NOS activity and reduced electrically stimulated contractility, while the inactive alpha-PDB was ineffectual. Contractility could be restored to beta-PDB-incubated cells by superfusion with the NOS inhibitor N omega-nitro-L-arginine methyl ester. PKC blockade with sphingosine, chelerythrine, or calphostin-C precluded LPS- and beta-PDB-induced increases in NOS activity and protected contractility. Depletion of PKC by 18 h of incubation with beta-PDB in the presence of chelerythrine also blocked acquisition of enhanced NOS activity and contractile dysfunction when the myocytes were subsequently exposed to LPS. These findings suggest that PKC is a significant intracellular mediator for the effects of LPS on cardiac cell NOS activity and contractile function.

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