Nitric oxide synthase in porcine heart mitochondria: evidence for low physiological activity

2001 ◽  
Vol 280 (6) ◽  
pp. H2863-H2867 ◽  
Author(s):  
Stephanie French ◽  
Cecilia Giulivi ◽  
R. S. Balaban
Keyword(s):  
Nitric Oxide ◽  
Physiological Activity ◽  
Mitochondrial Protein ◽  
Metabolic Effects ◽  
Heart Mitochondria ◽  
No Production ◽  
Porcine Heart ◽  
Nos Inhibitors ◽  
Oxide Synthase ◽  
Intact Heart

The capacity of isolated porcine heart mitochondria to produce nitric oxide (NO) via mitochondrial NO synthase (NOS) was evaluated. The mitochondrial NOS content and activity (0.2 nmol NO · mg mitochondrial protein−1 · min−1) were ∼10 times lower than previously reported for the rat liver. No evidence for mitochondrial NOS-generated NO was found in mitochondrial suspensions based on the lack of NO production and the lack of effect of eitherl-arginine or NOS inhibitors on the rate of respiration. The reason that even the low mitochondrial NOS activity did not result in net NO production and metabolic effects is because the mitochondrial metabolic breakdown of NO (1–4 nmol NO · mg mitochondrial protein−1 · min−1) was greater than the maximum rate of NO production measured in homogenates. These data suggest that NO production at the mitochondria via NOS is not a significant source of NO in the intact heart and does not regulate cardiac oxidative phosphorylation.

Single oral inoculation with Escherichia coli (ATCC 25922) stimulates generalised production of nitric oxide in mice

2009 ◽  
Vol 57 (1) ◽  
pp. 127-138 ◽  
Author(s):  
Ana Nemec ◽  
Zlatko Pavlica ◽  
David Crossley ◽  
Irena Zdovc ◽  
Damijan Eržen ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Escherichia Coli ◽  
Spin Trap ◽  
Oral Route ◽  
No Production ◽  
Paramagnetic Resonance ◽  
E Coli ◽  
Oral Inoculation ◽  
Nos Inhibitors ◽  
Oxide Synthase

Nitric oxide (NO) production was investigated in the lungs, thoracic aorta, heart, liver, spleen, kidneys and brain of mice inoculated orally withEscherichia coliATCC 25922. Detection of NO was performed by electron paramagnetic resonance (EPR) using diethyldithiocarbamate (DETC) spin trap. Nitric oxide synthase (NOS) inhibitors [nonselective: L-NAME and inducible NOS (iNOS) selective: 1400W] were used to determine the source of NO. Spin-trap only and untreated mice were included as controls. Within 2.5 hours (h) of a single oral inoculation withE. colihalf of the animals had increased NO levels in all investigated organs. Thereafter the signals dropped before increasing again to reach maximal median values by 25 h in all organs of all inoculated mice. The most intense response occurred in livers, followed by aorta and lungs. Early (2.5 h) inhibition of the signal was achieved using both NOS inhibitors. L-NAME was also effective at 25 h, while 1400W-treated mice had increased NO levels beyond 7 h. The generalised increase in NO production in the short and longer term indicates a host response toE. coliadministered by the oral route of infection.

In vivo pharmacological evaluation off two novel type II (inducible) nitric oxide synthase inhibitors

1995 ◽  
Vol 73 (5) ◽  
pp. 665-669 ◽  
Author(s):  
W. Ross Tracey ◽  
Masaki Nakane ◽  
Fatima Basha ◽  
George Carter
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Inducible Nitric Oxide Synthase ◽  
No Production ◽  
Type Ii ◽  
Nos Inhibitors ◽  
Oxide Synthase ◽  
Dose Dependent ◽  
Inducible Nitric Oxide

Selective type II (inducible) nitric oxide synthase (NOS) inhibitors have several potential therapeutic applications, including treatment of sepsis, diabetes, and autoimmune diseases. The ability of two novel, selective inhibitors of type II NOS, S-ethylisothiourea (EIT) and 2-amino-5,6-dihydro-6-methyl-4H-1,3-thiazine (AMT), to inhibit type II NOS function in vivo was studied in lipopolysaccharide (LPS) treated rats. Type II NOS activity was assessed by measuring changes in plasma nitrite and nitrate concentrations ([NOx]). Both EIT and AMT elicited a dose-dependent and >95% inhibition of the LPS-induced increase in plasma [NOx]. The ED50 values for EIT and AMT were 0.4 and 0.2 mg/kg, respectively. In addition, the administration of LPS and either NOS inhibitor resulted in a dose-dependent increase in animal mortality; neither compound was lethal when administered alone. Pretreatment with L-arginine (but not D-arginine) prevented the mortality, while not affecting the type II NOS-dependent NO production, suggesting the toxicity may be due to inhibition of one of the other NOS isoforms (endothelial or neuronal). Thus, although EIT and AMT are potent inhibitors of type II NOS function in vivo, type II NOS inhibitors of even greater selectivity may need to be developed for therapeutic applications.Key words: nitric oxide, nitrite, nitrate, sepsis, lipopolysaccharide.

Neuronal nitric oxide synthase-derived hydrogen peroxide is a major endothelium-dependent relaxing factor

2008 ◽  
Vol 295 (6) ◽  
pp. H2503-H2511 ◽  
Author(s):  
L. S. A. Capettini ◽  
S. F. Cortes ◽  
M. A. Gomes ◽  
G. A. B. Silva ◽  
J. L. Pesquero ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Constitutive Expression ◽  
Selective Inhibition ◽  
No Production ◽  
Relaxing Factor ◽  
Antisense Knockdown ◽  
Nos Inhibitors ◽  
Mouse Aorta ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide

Endothelium-dependent vasorelaxation in large vessels is mainly attributed to Nω-nitro-l-arginine methyl ester (l-NAME)-sensitive endothelial nitric oxide (NO) synthase (eNOS)-derived NO production. Endothelium-derived hyperpolarizing factor (EDHF) is the component of endothelium-dependent relaxations that resists full blockade of NO synthases (NOS) and cyclooxygenases. H2O2 has been proposed as an EDHF in resistance vessels. In this work we propose that in mice aorta neuronal (n)NOS-derived H2O2 accounts for a large proportion of endothelium-dependent ACh-induced relaxation. In mice aorta rings, ACh-induced relaxation was inhibited by l-NAME and Nω-nitro-l-arginine (l-NNA), two nonselective inhibitors of NOS, and attenuated by selective inhibition of nNOS with l-ArgNO2-L-Dbu-NH2 2TFA (L-ArgNO2-L-Dbu) and 1-(2-trifluoromethylphehyl)imidazole (TRIM). The relaxation induced by ACh was associated with enhanced H2O2 production in endothelial cells that was prevented by the addition of l-NAME, l-NNA, L-ArgNO2-L-Dbu, TRIM, and removal of the endothelium. The addition of catalase, an enzyme that degrades H2O2, reduced ACh-dependent relaxation and abolished ACh-induced H2O2 production. RT-PCR experiments showed the presence of mRNA for eNOS and nNOS but not inducible NOS in mice aorta. The constitutive expression of nNOS was confirmed by Western blot analysis in endothelium-containing vessels but not in endothelium-denuded vessels. Immunohistochemistry data confirmed the localization of nNOS in the vascular endothelium. Antisense knockdown of nNOS decreased both ACh-dependent relaxation and ACh-induced H2O2 production. Antisense knockdown of eNOS decreased ACh-induced relaxation but not H2O2 production. Residual relaxation in eNOS knockdown mouse aorta was further inhibited by the selective inhibition of nNOS with L-ArgNO2-L-Dbu. In conclusion, these results show that nNOS is constitutively expressed in the endothelium of mouse aorta and that nNOS-derived H2O2 is a major endothelium-dependent relaxing factor. Hence, in the mouse aorta, the effects of nonselective NOS inhibitors cannot be solely ascribed to NO release and action without considering the coparticipation of H2O2 in mediating vasodilatation.

Contributions of nitric oxide synthase isozymes to exhaled nitric oxide and hypoxic pulmonary vasoconstriction in rabbit lungs

2003 ◽  
Vol 284 (5) ◽  
pp. L834-L843 ◽  
Author(s):  
David J. Vaughan ◽  
Thomas V. Brogan ◽  
Mark E. Kerr ◽  
Steven Deem ◽  
Daniel L. Luchtel ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Hypoxic Pulmonary Vasoconstriction ◽  
Exhaled Nitric Oxide ◽  
No Production ◽  
Rabbit Lung ◽  
Pulmonary Vasoconstriction ◽  
Exhaled No ◽  
Nos Inhibitors ◽  
Oxide Synthase

We investigated the source(s) for exhaled nitric oxide (NO) in isolated, perfused rabbits lungs by using isozyme-specific nitric oxide synthase (NOS) inhibitors and antibodies. Each inhibitor was studied under normoxia and hypoxia. Only nitro-l-arginine methyl ester (l-NAME, a nonselective NOS inhibitor) reduced exhaled NO and increased hypoxic pulmonary vasoconstriction (HPV), in contrast to 1400W, an inhibitor of inducible NOS (iNOS), and 7-nitroindazole, an inhibitor of neuronal NOS (nNOS). Acetylcholine-mediated stimulation of vascular endothelial NOS (eNOS) increased exhaled NO and could only be inhibited by l-NAME. Selective inhibition of airway and alveolar epithelial NO production by nebulized l-NAME decreased exhaled NO and increased hypoxic pulmonary artery pressure. Immunohistochemistry demonstrated extensive staining for eNOS in the epithelia, vasculature, and lymphatic tissue. There was no staining for iNOS but moderate staining for nNOS in the ciliated cells of the epithelia, lymphoid tissue, and cartilage cells. Our findings show virtually all exhaled NO in the rabbit lung is produced by eNOS, which is present throughout the airways, alveoli, and vessels. Both vascular and epithelial-derived NO modulate HPV.

Roles of accumulated endogenous nitric oxide synthase inhibitors, enhanced arginase activity, and attenuated nitric oxide synthase activity in endothelial cells for pulmonary hypertension in rats

2007 ◽  
Vol 292 (6) ◽  
pp. L1480-L1487 ◽  
Author(s):  
Akihito Sasaki ◽  
Shouzaburoh Doi ◽  
Shuki Mizutani ◽  
Hiroshi Azuma
Keyword(s):  
Nitric Oxide ◽  
Endothelial Cells ◽  
Pulmonary Hypertension ◽  
Nitric Oxide Synthase ◽  
Pulmonary Artery ◽  
Protein Expression ◽  
No Production ◽  
Nos Inhibitors ◽  
Endogenous Nitric Oxide ◽  
Oxide Synthase

Nitric oxide (NO) has been suggested to play a key role in the pathogenesis of pulmonary hypertension (PH). To determine which mechanism exists to affect NO production, we examined the concentration of endogenous nitric oxide synthase (NOS) inhibitors and their catabolizing enzyme dimethylarginine dimethylaminohydrolase (DDAH) activity and protein expression (DDAH1 and DDAH2) in pulmonary artery endothelial cells (PAECs) of rats given monocrotaline (MCT). We also measured NOS and arginase activities and NOS protein expression. Twenty-four days after MCT administration, PH and right ventricle (RV) hypertrophy were established. Endothelium-dependent, but not endothelium-independent, relaxation and cGMP production were significantly impaired in pulmonary artery specimens of MCT group. The constitutive NOS activity and protein expression in PAECs were significantly reduced in MCT group, whereas the arginase, which shares l-arginine as a common substrate with NOS, activity was significantly enhanced in PAECs of MCT group. The contents of monomethylarginine (MMA) and asymmetric dimethylarginine (ADMA), but not symmetric dimethylarginine (SDMA), were increased in PAECs of MCT group. The DDAH activity and DDAH1, but not DDAH2, protein expression were significantly reduced in PAECs of MCT group. These results suggest that the impairment of cGMP production as a marker of NO production is possibly due to the blunted endothelial NOS activity resulting from the downregulation of endothelial NOS protein, accumulation of endogenous NOS inhibitors, and accelerated arginase activity in PAECs of PH rats. The decreased overall DDAH activity accompanied by the downregulation of DDAH1 would bring about the accumulation of endogenous NOS inhibitors.

scholarly journals Regulation of cyclooxygenase activity and progesterone production in the rat corpus luteum by inducible nitric oxide synthase

Reproduction ◽  
2002 ◽  
pp. 663-669 ◽  
Author(s):  
A Hurwitz ◽  
Z Finci-Yeheskel ◽  
A Milwidsky ◽  
M Mayer
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Corpus Luteum ◽  
Prostaglandin E ◽  
No Production ◽  
Luteal Cells ◽  
Progesterone Production ◽  
Nos Inhibitors ◽  
Nos Inhibitor ◽  
Oxide Synthase

This study explores interactions between the nitric oxide synthase (NOS) and the cyclooxygenase (COX) pathways in the regulation of progesterone production in early corpus luteum cells of rats. Nitric oxide (NO), prostaglandin E (PGE) and progesterone production was analysed in luteal cells of the rat corpus luteum exposed to inhibitors of non-specific NOS, inhibitors of inducible NOS (iNOS) and inhibitors of COX. Equine chorionic gonadotrophin (eCG)/hCG-primed rat corpus luteum cells produced NO, PGE and progesterone in a linear manner during 66 h of culture. Exposure of the cells to the non-specific NOS inhibitor, N(omega)-nitro-L-arginine (0.15 mmol l(-1)) for 48 h reduced NO, PGE and progesterone production to 21, 32 and 60% of that of the controls, respectively (P < 0.05 to P < 0.01). Another non-specific NOS inhibitor, N(omega)-methyl-L-arginine, produced similar inhibitions. Exposure of the cultured cells to S-ethylisothiourea (1 mmol l(-1)), a selective inhibitor of iNOS, suppressed the production of NO by 63%, PGE by 69% and progesterone by 48%. These findings indicate that production of PGE is regulated partly by iNOS, and that progesterone is probably regulated indirectly by the secondary changes in PGE. The addition of arachidonic acid to N(omega)-methyl-L-arginine-treated cells resulted in a significant increase in PGE and progesterone production (273 and 186%, respectively) without stimulating NO production. In contrast to the regulation exerted by the NO system on COX activity, the COX system does not modulate NO production in this model. This notion stems from the observation that the COX inhibitors acetylsalicylic acid (5 mmol l(-1)) and indomethacin (5 micromol l(-1)) suppressed PGE by 86 and 89%, respectively, and progesterone by 34 and 57%, respectively, but failed to inhibit NO production. The results from the present study indicate that iNOS-mediated NO production is involved in stimulating PGE synthesis in rat luteal cells, which may upregulate progesterone production.

scholarly journals Activation of the TRKB receptor mediates the panicolytic-like effect of NOS inhibitor aminoguanidine

2018 ◽  
Author(s):  
DE Ribeiro ◽  
PC Casarotto ◽  
A Spiacci ◽  
GG Fernandes ◽  
LC Pinheiro ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Antidepressant Drugs ◽  
No Production ◽  
Periaqueductal Gray Matter ◽  
Nos Inhibitors ◽  
Escape Reaction ◽  
Nos Inhibitor ◽  
Bdnf Signaling ◽  
Oxide Synthase

AbstractNitric oxide (NO) triggers escape reactions in the dorsal periaqueductal gray matter (dPAG), a core structure mediating panic-associated responses, and decreases the release of BDNF in vitro. BDNF mediates the panicolytic effect induced by antidepressant drugs and produces these effects per se when injected into the dPAG. Based on these findings, we hypothesize that nitric oxide synthase (NOS) inhibitors would have panicolytic properties associated with increased BDNF signaling in the dPAG. We observed that the repeated (7 days), but not acute (1day), systemic administration of the NOS inhibitor aminoguanidine (AMG; 15 mg/kg/day) increased the latency to escape from the open arm of the elevated T-maze (ETM) and inhibited the number of jumps in hypoxia-induced escape reaction in rats, suggesting a panicolytic-like effect. Repeated, but not acute, AMG administration (15mg/kg) also decreased nitrite levels and increased TRKB phosphorylation at residues Y706/7 in the dPAG. Notwithstanding the lack of AMG effect on total BDNF levels in that structure, the microinjection of the TRK antagonist K252a into the dPAG blocked the anti-escape effect of this drug in the ETM. Taken together our data suggest that the inhibition of NO production by AMG increased the levels of pTRKB, which is required for the panicolytic-like effect observed.

Role of nitric oxide synthase isoforms in glucose-stimulated insulin release

2002 ◽  
Vol 283 (1) ◽  
pp. C296-C304 ◽  
Author(s):  
Ragnar Henningsson ◽  
Albert Salehi ◽  
Ingmar Lundquist
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Insulin Release ◽  
Type Ii Diabetes Mellitus ◽  
No Production ◽  
No Donor ◽  
Nos Inhibitors ◽  
Constitutive Nitric Oxide Synthase ◽  
Oxide Synthase

The role of islet constitutive nitric oxide synthase (cNOS) in insulin-releasing mechanisms is controversial. By measuring enzyme activities and protein expression of NOS isoforms [i.e., cNOS and inducible NOS (iNOS)] in islets of Langerhans cells in relation to insulin secretion, we show that glucose dose-dependently stimulates islet activities of both cNOS and iNOS, that cNOS-derived nitric oxide (NO) strongly inhibits glucose-stimulated insulin release, and that short-term hyperglycemia in mice induces islet iNOS activity. Moreover, addition of NO gas or an NO donor inhibited glucose-stimulated insulin release, and different NOS inhibitors effected a potentiation. These effects were evident also in K+-depolarized islets in the presence of the ATP-sensitive K+ channel opener diazoxide. Furthermore, our results emphasize the necessity of measuring islet NOS activity when using NOS inhibitors, because certain concentrations of certain NOS inhibitors might unexpectedly stimulate islet NO production. This is shown by the observation that 0.5 mmol/l of the NOS inhibitor N G-monomethyl-l-arginine (l-NMMA) stimulated cNOS activity in parallel with an inhibition of the first phase of glucose-stimulated insulin release in perifused rats islets, whereas 5.0 mmol/l of l-NMMA markedly suppressed cNOS activity concomitant with a great potentiation of the insulin secretory response. The data strongly suggest, but do not definitely prove, that glucose indeed has the ability to stimulate both cNOS and iNOS in the islets and that NO might serve as a negative feedback inhibitor of glucose-stimulated insulin release. The results also suggest that hyperglycemia-evoked islet NOS activity might be one of multiple factors involved in the impairment of glucose-stimulated insulin release in type II diabetes mellitus.

The Signaling Pathways in Nitric Oxide Production by Neutrophils Exposed to N-nitrosodimethylamine

2018 ◽  
Vol 16 (2) ◽  
pp. 194-199
Author(s):  
Wioletta Ratajczak-Wrona ◽  
Ewa Jablonska
Keyword(s):  
Nitric Oxide ◽  
Signaling Pathways ◽  
Molecular Mechanisms ◽  
Polymorphonuclear Neutrophils ◽  
Microbial Pathogens ◽  
Human Neutrophils ◽  
No Production ◽  
Oxide Synthase ◽  
Inducible Nitric Oxide

Background: Polymorphonuclear neutrophils (PMNs) play a crucial role in the innate immune system’s response to microbial pathogens through the release of reactive nitrogen species, including Nitric Oxide (NO). </P><P> Methods: In neutrophils, NO is produced by the inducible Nitric Oxide Synthase (iNOS), which is regulated by various signaling pathways and transcription factors. N-nitrosodimethylamine (NDMA), a potential human carcinogen, affects immune cells. NDMA plays a major part in the growing incidence of cancers. Thanks to the increasing knowledge on the toxicological role of NDMA, the environmental factors that condition the exposure to this compound, especially its precursors- nitrates arouse wide concern. Results: In this article, we present a detailed summary of the molecular mechanisms of NDMA’s effect on the iNOS-dependent NO production in human neutrophils. Conclusion: This research contributes to a more complete understanding of the mechanisms that explain the changes that occur during nonspecific cellular responses to NDMA toxicity.

Inducible nitric oxide synthase augments injury elicited by oxidative stress in rat cardiac myocytes

1998 ◽  
Vol 274 (1) ◽  
pp. C245-C252 ◽  
Author(s):  
Junsuke Igarashi ◽  
Masashi Nishida ◽  
Shiro Hoshida ◽  
Nobushige Yamashita ◽  
Hiroaki Kosaka ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Nitric Oxide ◽  
Cardiac Myocytes ◽  
Myocardial Injury ◽  
No Production ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
No Donor ◽  
Oxide Synthase ◽  
Gpx Activity

The effects of nitric oxide (NO) produced by cardiac inducible NO synthase (iNOS) on myocardial injury after oxidative stress were examined. Interleukin-1β induced cultured rat neonatal cardiac myocytes to express iNOS. After induction of iNOS,l-arginine enhanced NO production in a concentration-dependent manner. Glutathione peroxidase (GPX) activity in myocytes was attenuated by elevated iNOS activity and by an NO donor, S-nitroso- N-acetyl-penicillamine (SNAP). Although NO production by iNOS did not induce myocardial injury, NO augmented release of lactate dehydrogenase from myocyte cultures after addition of H2O2(0.1 mM, 1 h). Inhibition of iNOS with Nω-nitro-l-arginine methyl ester ameliorated the effects of NO-enhancing treatments on myocardial injury and GPX activity. SNAP augmented the myocardial injury induced by H2O2. Inhibition of GPX activity with antisense oligodeoxyribonucleotide for GPX mRNA increased myocardial injury by H2O2. Results suggest that the induction of cardiac iNOS promotes myocardial injury due to oxidative stress via inactivation of the intrinsic antioxidant enzyme, GPX.

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