scholarly journals Endotoxin-induced skeletal muscle contractile dysfunction: contribution of nitric oxide synthases

1998 ◽  
Vol 274 (3) ◽  
pp. C770-C779 ◽  
Author(s):  
Q. El-Dwairi ◽  
A. Comtois ◽  
Y. Guo ◽  
S. N. A. Hussain
Keyword(s):  
Nitric Oxide ◽  
Skeletal Muscle ◽  
No Production ◽  
Contractile Dysfunction ◽  
Nos Inhibitor ◽  
Nos Isoforms ◽  
Muscle Contractile ◽  
Inducible Nos

The aims of this study were to assess the role of nitric oxide (NO) and the contribution of different NO synthase (NOS) isoforms in skeletal muscle contractile dysfunction in septic shock. Four groups of conscious rats were examined. Group 1 served as control; groups 2, 3, and 4 were injected with Escherichia coli endotoxin [lipopolysaccharide (LPS), 20 mg/kg ip] and killed after 6, 12, and 24 h, respectively. Protein expression was assessed by immunoblotting and immunostaining. LPS injection elicited a transient expression of the inducible NOS isoform, which peaked 12 h after LPS injection and disappeared within 24 h. This expression coincided with a significant increase in nitrotyrosine formation (peroxynitrite footprint). Muscle expression of the endothelial and neuronal NOS isoforms, by comparison, rose significantly and remained higher than control levels 24 h after LPS injection. In vitro measurement of muscle contractility 24 h after LPS injection showed that incubation with NOS inhibitor ( S-methyliosothiourea) restored the decline in submaximal force generation, whereas maximal muscle force remained unaffected. We conclude that NO plays a significant role in muscle contractile dysfunction in septic animals and that increased NO production is due to induction of the inducible NOS isoform and upregulation of constitutive NOS isoforms.

scholarly journals Estrogen Induces Nitric Oxide Production via Activation of Constitutive Nitric Oxide Synthases in Human Neuroblastoma Cells

Endocrinology ◽  
2004 ◽  
Vol 145 (10) ◽  
pp. 4550-4557 ◽  
Author(s):  
Yun Xia ◽  
Teresa L. Krukoff
Keyword(s):  
Nitric Oxide ◽  
Neuroblastoma Cells ◽  
No Production ◽  
Tetraacetic Acid ◽  
Acetoxymethyl Ester ◽  
No Release ◽  
Nos Inhibitor ◽  
Neuronal Nos ◽  
Nos Isoforms ◽  
Inducible Nos

Abstract Although it is becoming increasingly evident that nitric oxide (NO) mediates some of estrogen’s actions in the brain, the effects of estrogen on NO production through NO synthases (NOS) in neuronal cells have not yet been identified. Here we assessed changes in NO production induced by 17β-estradiol (E2) in cells of neuronal origin using human SK-N-SH neuroblastoma cells, which we show express all three isoforms of NOS. Involvement of NOS isoforms in E2-induced NO production was examined using isoform-specific NOS inhibitors. E2 (10−10–10−6m) induced rapid increases in NO release and changes in endothelial NOS (eNOS) expression, which were blocked by ICI 182,780, an antagonist of estrogen receptors. Increased levels of NO release and NOS activity induced by E2 were blocked by N5-(1-Imino-3-butenyl)-l-ornithine, a neuronal NOS inhibitor, and N5-(1-Iminoethyl)-l-ornithine, an eNOS inhibitor, but not by 1400W, an inducible NOS inhibitor. These results demonstrate that E2-stimulated NO production occurs via estrogen receptor-mediated activation of the constitutive NOSs, neuronal NOS and eNOS. The E2-induced NO increase was abolished when extracellular Ca2+ was removed from the medium or after the addition of nifedipine, an L-type channel blocker, and was partially inhibited using 1,2-bis(2-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid acetoxymethyl ester, an intracellular Ca2+ chelator. However, 1,2-bis(2-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid acetoxymethyl ester itself also caused an increase in NO release that was blocked by 1400W, suggesting that inducible NOS mediates this response. Together these data reveal that constitutive NOS activities are responsible for E2- induced NO production in neuroblastoma cells and that differential activation of NOS isoforms in these cells occurs in response to different treatments.

scholarly journals Protective Role of Nitric Oxide in a Model of Thrombotic Microangiopathy in Rats

2001 ◽  
Vol 12 (10) ◽  
pp. 2088-2097
Author(s):  
JING SHAO ◽  
TOSHIO MIYATA ◽  
KOEI YAMADA ◽  
NORIO HANAFUSA ◽  
TAKEHIKO WADA ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Endothelial Cells ◽  
Thrombotic Microangiopathy ◽  
Periodic Acid ◽  
Minor Role ◽  
Protective Mechanism ◽  
No Production ◽  
Nos Inhibitor ◽  
Inducible Nos

Abstract. A new model of thrombotic microangiopathy (TMA) was previously developed, and it was demonstrated that endothelial nitric oxide (NO) synthase (NOS) is upregulated in glomeruli in this model. It was hypothesized that the synthesis of NO, a potent vasodilator and platelet inhibitory factor, is induced as a defense mechanism. The goal of this study was to clarify the role of NO in this model.Ex vivoexperiments using Western blotting and functional assays demonstrated upregulation of endothelial NOS in isolated glomeruli from TMA rats. Inin vivoexperiments, five groups of rats were studied, including rats with TMA treated with vehicle,NG-nitro-L-arginine methyl ester (L-NAME) (a NOS inhibitor), or L-N6-(1-iminoethyl)lysine (L-NIL) (a specific inducible NOS inhibitor) and normal control rats treated with vehicle or L-NAME. Blood urea nitrogen levels, BP, urinary nitrate/nitrite excretion, and proteinuria were measured. Histologic assessments using periodic acid-Schiff staining and immunohistologic studies with markers for endothelium, platelets, fibrin, cell proliferation, and apoptosis were also performed. L-NAME inhibition of NO synthesis in rats with TMA resulted in more severe glomerular and tubulointerstitial injury, which was accompanied by thrombus formation and a marked loss of endothelial cells, with more apoptotic cells. These changes were associated with severe renal function deterioration. In contrast, these features were less pronounced in the vehicle- or L-NIL-treated rats with TMA and were absent in the control animals. In conclusion, inhibition of NO production in this model of TMA markedly exacerbated renal injury. The absence of effects with L-NIL treatment suggests a minor role for inducible NOS in this model. These results suggest that production of NO, most likely by endothelial cells, is an important protective mechanism in TMA.

scholarly journals l-Arginine Availability Modulates Local Nitric Oxide Production and Parasite Killing in Experimental Trypanosomiasis

2000 ◽  
Vol 68 (8) ◽  
pp. 4653-4657 ◽  
Author(s):  
Alain P. Gobert ◽  
Sylvie Daulouede ◽  
Michel Lepoivre ◽  
Jean Luc Boucher ◽  
Bernard Bouteille ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Peritoneal Macrophages ◽  
No Production ◽  
Nitrite Production ◽  
Common Substrate ◽  
Nos Inhibitor

ABSTRACT Nitric oxide (NO) is an important effector molecule of the immune system in eliminating numerous pathogens. Peritoneal macrophages fromTrypanosoma brucei brucei-infected mice express type II NO synthase (NOS-II), produce NO, and kill parasites in the presence ofl-arginine in vitro. Nevertheless, parasites proliferate in the vicinity of these macrophages in vivo. The present study shows thatl-arginine availability modulates NO production. Trypanosomes use l-arginine for polyamine synthesis, required for DNA and trypanothione synthesis. Moreover, arginase activity is up-regulated in macrophages from infected mice from the first days of infection. Arginase competes with NOS-II for their common substrate, l-arginine. In vitro, arginase inhibitors decreased urea production, increased macrophage nitrite production, and restored trypanosome killing. In vivo, a dramatic decrease inl-arginine concentration was observed in plasma from infected mice. In situ restoration of NO production and trypanosome killing were observed when excess l-arginine, but notd-arginine or l-arginine plusN ω-nitro-l-arginine (a NOS inhibitor), was injected into the peritoneum of infected mice. These data indicate the role of l-arginine depletion, induced by arginase and parasites, in modulating the l-arginine–NO pathway under pathophysiological conditions.

Losartan Increases No Production from the Bovine Aortic Wall That is Stimulated by Angiotensin II

2003 ◽  
Vol 1 (3) ◽  
pp. 113-117 ◽  
Author(s):  
M. Myronidou ◽  
B. Kokkas ◽  
A. Kouyoumtzis ◽  
N. Gregoriadis ◽  
A. Lourbopoulos ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Angiotensin Ii ◽  
Aortic Wall ◽  
Vascular Wall ◽  
Protective Role ◽  
Normal Function ◽  
No Production ◽  
Chemical Inactivation

In these studies we investigated if losartan, an AT1- receptor blocker has any beneficial effect on NO production from the bovine aortic preparations in vitro while under stimulation from angiotensin II. Experiments were performed on intact specimens of bovine thoracic aorta, incubated in Dulbeco's MOD medium in a metabolic shaker for 24 hours under 95 % O2 and 5 % CO2 at a temperature of 37°C. We found that angiotensin II 1nM−10 μM does not exert any statistically significant action on NO production. On the contrary, angiotensin II 10nM increases the production of NO by 58.14 % (from 12.16 + 2.9 μm/l to 19.23 + 4.2 μm/l in the presence of losartan 1nM (P<0.05). Nitric oxide levels depend on both rate production and rate catabolism or chemical inactivation. Such an equilibrium is vital for the normal function of many systems including the cardiovascular one. The above results demonstrate that the blockade of AT1-receptors favors the biosynthesis of NO and indicate the protective role of losartan on the vascular wall.

Does autonomic blockade reveal a potent contribution of nitric oxide to locomotion-induced vasodilation?

2000 ◽  
Vol 279 (2) ◽  
pp. H726-H732 ◽  
Author(s):  
Don D. Sheriff ◽  
Christopher D. Nelson ◽  
Ryan K. Sundermann
Keyword(s):  
Nitric Oxide ◽  
Skeletal Muscle ◽  
No Production ◽  
Vascular Conductance ◽  
Absolute Level ◽  
Autonomic Blockade ◽  
The Absolute ◽  
Ganglionic Transmission ◽  
Treadmill Locomotion

We sought to test the role of nitric oxide (NO) in governing skeletal muscle (iliac) vascular conductance during treadmill locomotion in dogs ( n = 6; 3.2 and 6.4 km/h at 0% grade, and 6.4 km/h at 10% grade). As seen previously, the increase in muscle vascular conductance accompanying treadmill locomotion was little influenced by NO synthase inhibition alone with N ω-nitro-l-arginine methyl ester (l-NAME, 10 mg/kg iv), but the absolute value of conductance achieved during locomotion was reduced. Such ambiguous results provide an unclear picture regarding the importance of NO during locomotion. However, muscle vasodilation is normally restrained by the sympathetic system during locomotion. Thus a significant contribution by NO to the increase in vascular conductance that accompanies locomotion could be masked by partial withdrawal of the competing influence of sympathetic vasoconstrictor nerve activity secondary to the rise in arterial pressure following systemicl-NAME administration. To test this possibility, we compared the rise in muscle vascular conductance before and afterl-NAME treatment while ganglionic transmission was blocked by hexamethonium. Under these conditions, l-NAME significantly reduced both the rise in vascular conductance (by 32%, P < 0.001) and the absolute level of vascular conductance (by 30%, P < 0.001) achieved during locomotion with no effect on blood flow. Thus augmented NO production normally provides a significant drive to relax vascular smooth muscle in active skeletal muscle during locomotion. Potential deficits stemming from the absence of NO following l-NAME treatment are masked by less intense sympathetic restraint when autonomic function is intact.

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 Regulatory Role of GSK-3βon NF-κB, Nitric Oxide, and TNF-αin Group A Streptococcal Infection

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Yu-Tzu Chang ◽  
Chia-Ling Chen ◽  
Chiou-Feng Lin ◽  
Shiou-Ling Lu ◽  
Miao-Huei Cheng ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Mouse Model ◽  
Group A Streptococcus ◽  
Glycogen Synthase ◽  
Critical Issue ◽  
No Production ◽  
Group A ◽  
Oxide Synthase

Group A streptococcus (GAS) imposes a great burden on humans. Efforts to minimize the associated morbidity and mortality represent a critical issue. Glycogen synthase kinase-3β(GSK-3β) is known to regulate inflammatory response in infectious diseases. However, the regulation of GSK-3βin GAS infection is still unknown. The present study investigates the interaction between GSK-3β, NF-κB, and possible related inflammatory mediators in vitro and in a mouse model. The results revealed that GAS could activate NF-κB, followed by an increased expression of inducible nitric oxide synthase (iNOS) and NO production in a murine macrophage cell line. Activation of GSK-3βoccurred after GAS infection, and inhibition of GSK-3βreduced iNOS expression and NO production. Furthermore, GSK-3βinhibitors reduced NF-κB activation and subsequent TNF-αproduction, which indicates that GSK-3βacts upstream of NF-κB in GAS-infected macrophages. Similar to the in vitro findings, administration of GSK-3βinhibitor in an air pouch GAS infection mouse model significantly reduced the level of serum TNF-αand improved the survival rate. The inhibition of GSK-3βto moderate the inflammatory effect might be an alternative therapeutic strategy against GAS infection.

Sources and implications of basal nitric oxide in spontaneous contractions of guinea pig taenia caeci

2003 ◽  
Vol 285 (4) ◽  
pp. G747-G753 ◽  
Author(s):  
Catalina Caballero-Alomar ◽  
Carmen Santos ◽  
Diego Lopez ◽  
M. Teresa Mitjavila ◽  
Pere Puig-Parellada
Keyword(s):  
Nitric Oxide ◽  
Guinea Pig ◽  
Inhibitory Effect ◽  
No Production ◽  
Paramagnetic Resonance ◽  
Synthase Inhibitor ◽  
Spontaneous Contractions ◽  
Electron Paramagnetic

We examined in vitro the source and role of basal nitric oxide (NO) in proximal segments of guinea pig taenia caeci in nonadrenergic, noncholinergic (NANC) conditions. Using electron paramagnetic resonance (EPR), we measured the effect of the NO synthase inhibitor NG-nitro-l-arginine methyl ester (l-NAME, 10–4 M), the neuronal blocker tetrodotoxin (TTX, 10–6 M), or both on spontaneous contractions and on the production of basal NO. Both l-NAME and TTX, when tested alone, increased the amplitude and frequency of contractions. NO production was abolished by l-NAME and was inhibited by 38% by TTX. When tested together, l-NAME in the presence of TTX or TTX in the presence of l-NAME had no further effect on the amplitude or frequency of spontaneous contractions, and the NO production was inhibited. These findings suggest that basal NO consists of TTX-sensitive and TTX-resistant components. The TTX-sensitive NO has an inhibitory effect on spontaneous contractions; the role of TTX-resistant NO is unknown.

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

Myogenic NOS and endogenous NO production are defective in colon from dystrophic (mdx) mice

2001 ◽  
Vol 281 (5) ◽  
pp. G1264-G1270 ◽  
Author(s):  
Flavia Mulè ◽  
Maria Giuliana Vannucchi ◽  
Letizia Corsani ◽  
Rosa Serio ◽  
Maria Simonetta Faussone-Pellegrini
Keyword(s):  
Nitric Oxide ◽  
Intraluminal Pressure ◽  
Mdx Mice ◽  
No Production ◽  
Free Solution ◽  
Mouse Colon ◽  
Voltage Dependent ◽  
Oxide Synthase ◽  
Nos Isoforms ◽  
Inducible Nos

The aim of the present study was to evaluate whether alterations in the distribution and/or function of nitric oxide synthase (NOS) could be involved in the development of the spontaneous mechanical tone observed in colon from dystrophic ( mdx) mice. By recording the intraluminal pressure of isolated colon from normal mice, we showed that N ω-nitro- l-arginine methyl ester (l-NAME) increased the tone, even in the presence of tetrodotoxin. The effect was prevented by l-arginine, nifedipine, or Ca2+-free solution. In colon from mdx mice, l-NAME was ineffective. Immunohistochemistry revealed that the presence and distribution of neuronal (nNOS), endothelial, and inducible NOS isoforms in smooth muscle cells and neurons of colon from mdx mice were the same as in controls. However, the expression of myogenic nNOS was markedly reduced in mdx mice. We conclude that there is a myogenic NOS in mouse colon that can tonically produce nitric oxide to limit influx of Ca2+ through L-type voltage-dependent channels and modulate the mechanical tone. This mechanism appears to be defective in mdx mice.

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