SABIIA - Sistema Aberto e Integrado de Informação em Agricultura (Sabiia)

Del-Bel,E.A.; Oliveira,P.R.; Oliveira,J.A.C.; Mishra,P.K.; Jobe,P.C.; Garcia-Cairasco,N..

The effect of acute (120 mg/kg) and chronic (25 mg/kg, twice a day, for 4 days) intraperitonial injection of the nitric oxide (NO) synthase (NOS) inhibitor NG-nitro-L-arginine (L-NOARG) was evaluated on seizure induction by drugs such as pilocarpine and pentylenetetrazole (PTZ) and by sound stimulation of audiogenic seizure-resistant (R) and audiogenic seizure-susceptible (S) rats. Seizures were elicited by a subconvulsant dose of pilocarpine (100 mg/kg) only after NOS inhibition. NOS inhibition also simultaneously potentiated the severity of PTZ-induced limbic seizures (60 mg/kg) and protected against PTZ-induced tonic seizures (80 mg/kg). The audiogenic seizure susceptibility of S or R rats did not change after similar treatments. In conclusion,...

Role of nitric oxide and superoxide in Giardia lamblia killing

Palavras-chave: Experimental epilepsy; Seizures; Forebrain; Brainstem; Pilocarpine; Pentylenetetrazol; Audiogenic seizures; Genetically epilepsy-prone rats; GEPR; Nitric oxide.

Ano: 1997

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1997000800010

Giardia lamblia trophozoites were incubated for 2 h with activated murine macrophages, nitric oxide (NO) donors or a superoxide anion generator (20 mU/ml xanthine oxidase plus 1 mM xanthine). Activated macrophages were cytotoxic to Giardia trophozoites (~60% dead trophozoites). This effect was inhibited (>90%) by an NO synthase inhibitor (200 µM) and unaffected by superoxide dismutase (SOD, 300 U/ml). Giardia trophozoites were killed by the NO donors, S-nitroso-acetyl-penicillamine (SNAP) and sodium nitroprusside (SNP) in a dose-dependent manner (LD50 300 and 50 µM, respectively). A dual NO-superoxide anion donor, 3-morpholino-sydnonimine hydrochloride (SIN-1), did not have a killing effect in concentrations up to 1 mM. However, when SOD (300 U/ml)...

The myth of nitric oxide in central cardiovascular control by the nucleus tractus solitarii

Palavras-chave: Nitric oxide; Macrophage; Peroxynitrite; Giardia lamblia; Cytotoxicity; Superoxide.

Ano: 1997

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1997000100015

Considerable evidence suggests that nitroxidergic mechanisms in the nucleus tractus solitarii (NTS) participate in cardiovascular reflex control. Much of that evidence, being based on responses to nitric oxide precursors or inhibitors of nitric oxide synthesis, has been indirect and circumstantial. We sought to directly determine cardiovascular responses to nitric oxide donors microinjected into the NTS and to determine if traditional receptor mechanisms might account for responses to certain of these donors in the central nervous system. Anesthetized adult Sprague Dawley rats that were instrumented for recording arterial pressure and heart rate were used in the physiological studies. Microinjection of nitric oxide itself into the NTS did not produce any...

Thioglycollate-elicited murine macrophages are cytotoxic to Mycoplasma arginini-infected YAC-1 tumor cells

Palavras-chave: Nitric oxide; Nucleus tractus solitarii; Cardiovascular control; Receptors; Nitrosothiol.

Ano: 1997

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1997000400013

Ribeiro-Dias,F.; Russo,M.; Nascimento,F.R.F.; Barbuto,J.A.M.; Timenetsky,J.; Jancar,S..

Macrophages are important components of natural immunity involved in inhibition of tumor growth and destruction of tumor cells. It is known that these cells can be activated for tumoricidal activity by lymphokines and bacterial products. We investigated whether YAC-1 tumor cells infected with Mycoplasma arginini stimulate nitric oxide (NO) release and macrophage cytotoxic activity. Thioglycollate-elicited macrophages from male BALB/c mice were co-cultured for 20 h with YAC-1 tumor cells infected or not with Mycoplasma arginini. The cytotoxic activity was evaluated by MTT assay and nitrite levels were determined with the Griess reagent. Thioglycollate-elicited macrophages co-cultured with noninfected YAC-1 cells showed low cytotoxic activity (34.7 ± 8.6%)...

The role of IL-12 in experimental Trypanosoma cruzi infection

Palavras-chave: Macrophages; Cytotoxicity; Mycoplasma; Tumor cells; Nitric oxide.

Ano: 1998

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1998001100010

Silva,J.S.; Aliberti,J.C.S.; Martins,G.A.; Souza,M.A.; Souto,J.T.; Pádua,M.A..

Host resistance to Trypanosoma cruzi infection is dependent on both natural and acquired immune responses. During the early acute phase of infection in mice, natural killer (NK) cell-derived IFN-g is involved in controlling intracellular parasite replication, mainly through the induction of nitric oxide biosynthesis by activated macrophages. We have shown that IL-12, a powerful inducer of IFN-g production by NK cells, is synthesized soon after trypomastigote-macrophage interaction. The role of IL-12 in the control of T. cruzi infection in vivo was determined by treating infected mice with anti-IL-12 monoclonal antibody (mAb) and analyzing both parasitemia and mortality during the...

Role of non-nitric oxide non-prostaglandin endothelium-derived relaxing factor(s) in bradykinin vasodilation

Palavras-chave: IL-12 Trypanosoma cruzi NK cells IFN-<; FONT FACE=Symbol>; G<; /font>; Nitric oxide.

Ano: 1998

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1998000100014

Resende,A.C.; Ballejo,G.; Salgado,M.C.O..

The most conspicuous effect of bradykinin following its administration into the systemic circulation is a transient hypotension due to vasodilation. In the present study most of the available evidence regarding the mechanisms involved in bradykinin-induced arterial vasodilation is reviewed. It has become firmly established that in most species vasodilation in response to bradykinin is mediated by the release of endothelial relaxing factors following the activation of B2-receptors. Although in some cases the action of bradykinin is entirely mediated by the endothelial release of nitric oxide (NO) and/or prostacyclin (PGI2), a large amount of evidence has been accumulated during the last 10 years indicating that a non-NO/PGI2 factor accounts for...

Evidence of interaction between fluoxetine and isosorbide dinitrate on neuroleptic-induced catalepsy in mice

Palavras-chave: Prostaglandin; Bradykinin; Nitric oxide; Cytochrome P450; Potassium channels; Endothelium-dependent vasodilation.

Ano: 1998

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1998000900017

Pires,J.G.P.; Fonseca,F.C.G.; Woelffel,A.B.; Futuro-Neto,H.A..

Drugs which influence 5-HTergic mechanisms can modify neuroleptic-induced catalepsy (NC) in rodents, a phenomenon produced by striatal dopamine (DA) receptor blockade. Previous research also suggests a role for endogenous nitric oxide (NO) in the modulation of striatal DAergic neurotransmission; in addition, NO seems to play a role in the 5-HT reuptake mechanism. It is known that clomipramine potentiates NC in mice, but the reported effects of selective 5-HT reuptake inhibitors (SSRIs) in this model are rather contradictory. We then decided to re-address this issue, investigating the effect of fluoxetine (FX), an SSRI, on NC. In view of the ubiquitous role of NO as a central neuromodulator, we also studied the effect of isosorbide dinitrate (ID), a...

Reversal by methylene blue of tetanic fade induced in cats by nitric oxide

Palavras-chave: Fluoxetine; Isosorbide dinitrate; Neuroleptic-induced catalepsy; Nitric oxide; Serotonin reuptake inhibitors; Dopaminergic transmission.

Ano: 1998

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1998000300014

Ambiel,C.R.; Alves-Do-Prado,W..

Previous data from our laboratory have indicated that nitric oxide (NO) acting at the presynaptic level increases the amplitude of muscular contraction (AMC) of the phrenic-diaphragm preparations isolated from indirectly stimulated rats, but, by acting at the postsynaptic level, it reduces the AMC when the preparations are directly stimulated. In the present study we investigated the effects induced by NO when tetanic frequencies of stimulation were applied to in vivo preparations (sciatic nerve-anterior tibial muscle of the cat). Intra-arterial injection of NO (0.75-1.5 mg/kg) induced a dose-dependent increase in the Wedensky inhibition produced by high frequencies of stimulation applied to the motor nerve. Intra-arterial administration of 7.2 µg/kg...

Endothelium-dependent vasodilation in response to Pseudomonas aeruginosa lipopolysaccharide: an in vitro study on canine arteries

Palavras-chave: Wedensky inhibition; Nitric oxide; Methylene blue; Skeletal muscle.

Ano: 1998

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1998000300013

Evora,P.R.B.; Ekin,S.; Pearson,P.J.; Schaff,H.V..

Early systemic arterial hypotension is a common clinical feature of Pseudomonas septicemia. To determine if Pseudomonas aeruginosa endotoxin induces the release of endothelium-derived nitric oxide (EDNO), an endogenous nitrovasodilator, segments of canine femoral, renal, hepatic, superior mesenteric, and left circumflex coronary arteries were suspended in organ chambers (physiological salt solution, 95% O2/5% CO2, pH 7.4, 37oC) to measure isometric force. In arterial segments contracted with 2 µM prostaglandin F2a, Pseudomonas endotoxin (lipopolysaccharide (LPS) serotype 10(Habs) from Pseudomonas aeruginosa (0.05 to 0.50 mg/ml)) induced concentration-dependent relaxation of segments with endothelium (P<0.05)...

Constitutive nitric oxide synthase (cNOS) activity in Langerhans islets from streptozotocin diabetic rats

Palavras-chave: Endothelium-derived relaxing factor; EDRF; Nitric oxide; Hypotension; Sepsis.

Ano: 1998

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1998001000014

Fonovich de Schroeder,T.M.; Carattino,M.D.; Frontera,M.; Catanzaro,O.L..

Nitric oxide synthase activity was measured in Langerhans islets isolated from control and streptozotocin diabetic rats. The activity of the enzyme was linear up to 150 µg of protein from control rats and was optimal at 0.1 µM calcium, when it was measured after 45 min of incubation at 37oC in the presence of 200 µM arginine. Specific activity of the enzyme was 25 x 10-4 nmol [3H]citrulline 45 min-1 mg protein-1. Streptozotocin diabetic rats exhibited less enzyme activity both in total pancreas homogenate and in isolated Langerhans islets when compared to control animals. Nitric oxide synthase activity measured in control and diabetic rats 15 days after the last streptozotocin injection in the second group of animals corresponded only to a constitutive...

Induction of cell-mediated immunity during early stages of infection with intracellular protozoa

Palavras-chave: Nitric oxide synthase; Nitric oxide; Langerhans islets; Streptozotocin; Diabetes.

Ano: 1998

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1998000500004

Gazzinelli,R.T.; Talvani,A.; Camargo,M.M.; Santiago,H.C.; Oliveira,M.A.P.; Vieira,L.Q.; Martins,G.A.; Aliberti,J.C.S.; Silva,J.S..

Toxoplasma gondii and Trypanosoma cruzi are intracellular parasites which, as part of their life cycle, induce a potent cell-mediated immunity (CMI) maintained by Th1 lymphocytes and IFN-g. In both cases, induction of a strong CMI is thought to protect the host against rapid parasite multiplication and consequent pathology and lethality during the acute phase of infection. However, the parasitic infection is not eliminated by the immune system and the vertebrate host serves as a parasite reservoir. In contrast, Leishmania sp, which is a slow growing parasite, appears to evade induction of CMI during early stages of infection as a strategy for surviving in a hostile environment (i.e., inside the macrophages which are...

Cytotoxic activity of BCG-activated macrophages against L929 tumor cells is nitric oxide-dependent

Palavras-chave: Leishmania; Toxoplasma gondii; Trypanosoma cruzi; Macrophages; Cytokines; Nitric oxide.

Ano: 1998

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1998000100012

Nascimento,F.R.F.; Ribeiro-Dias,F.; Russo,M..

The tumoricidal activity of activated macrophages has been attributed largely to the release of tumor necrosis factor (TNF), or to the production of reactive oxygen or nitrogen intermediates. The L929 tumor cell line (a murine fibroblast-like cell) when treated with actinomycin D (ActD) has been used to measure TNFa cytotoxicity. In the present study, we determined the cytotoxic activity of BCG-activated peritoneal macrophages against ActD-untreated L929 tumor cells. Furthermore, we measured the production of hydrogen peroxide (H2O2), nitric oxide (NO) and TNF by macrophages cultured in the presence or absence of L929 cells. As expected, BCG-activated macrophages produced significant amounts of H2O2 (16.0 ± 3.0 µM),...

Interferon gamma is a key cytokine in lung phase immunity to schistosomes but what is its precise role?

Palavras-chave: Cytotoxicity; Macrophages; L929 tumor cells; Nitric oxide; TNF; Hydrogen peroxide.

Ano: 1998

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1998001200012

Wilson,R.A..

Vaccination of mice with radiation-attenuated cercariae of Schistosoma mansoni induces a high level of protection against challenge with normal larvae. The immune effector mechanism, which operates in the lungs, is a cell-mediated delayed-type hypersensitivity response and involves the formation of a tight focus of mononuclear cells around embolised larvae. CD4+ T cells with Th1 characteristics are a major component of the infiltrate. They secrete abundant interferon gamma (IFNg) upon antigen stimulation in vitro, whilst in vivo neutralisation of the cytokine results in 90% abrogation of immunity. IFNg can induce a large number of genes and an attempt has been made to identify...

Effect of injection of L-NAME on drinking response

Palavras-chave: Interferon gamma; Schistosoma mansoni; Lung phase immunity; Nitric oxide; Adhesion molecule.

Ano: 1998

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1998000100022

Saad,W.A.; Camargo,L.A.A.; Saad,R.; Pereira,A.F.; Simões,S..

The drinking behavior responses to centrally administered NG-nitro-L-arginine methyl ester (L-NAME; 10, 20 or 40 µg/µl), an inhibitor of nitric oxide synthase, were studied in satiated rats, with cannulae stereotaxically implanted into the lateral ventricle (LV) and subfornical organ (SFO). Water intake increased in all animals after angiotensin II (ANG II) injection into the LV, with values of 14.2 ± 1.4 ml/h. After injection of L-NAME at doses of 10, 20 or 40 µg/µl into the SFO before injection of ANG II (12 ng/µl) into the LV, water intake decreased progressively and reached basal levels after treatment with 0.15 M NaCl and with the highest dose of L-NAME (i.e., 40 µg). The water intake obtained after 40 µg/µl L-NAME was 0.8 ± 0.01 ml/h. Also, the...

Effects of a neuronal nitric oxide synthase inhibitor on lipopolysaccharide-induced fever

Palavras-chave: Nitric oxide; Water intake; SFO; Dehydration; CNS.

Ano: 1999

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1999001100012

Perotti,C.A.A.; Nogueira,M.S.; Antunes-Rodrigues,J.; Cárnio,E.C..

It has been demonstrated that nitric oxide (NO) has a thermoregulatory action, but very little is known about the mechanisms involved. In the present study we determined the effect of neuronal nitric oxide synthase (nNOS) inhibition on thermoregulation. We used 7-nitroindazole (7-NI, 1, 10 and 30 mg/kg body weight), a selective nNOS inhibitor, injected intraperitoneally into normothermic Wistar rats (200-250 g) and rats with fever induced by lipopolysaccharide (LPS) (100 µg/kg body weight) administration. It has been demonstrated that the effects of 30 mg/kg of 7-NI given intraperitoneally may inhibit 60% of nNOS activity in rats. In all experiments the colonic temperature of awake unrestrained rats was measured over a period of 5 h at 15-min intervals...

Neuronal and endothelial nitric oxide synthase gene knockout mice

Palavras-chave: Nitric oxide; 7-nitroindazole; Body temperature; LPS; L-NAME.

Ano: 1999

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1999001100008

Huang,P.L..

Targeted disruption of the neuronal nitric oxide synthase (nNOS) and endothelial nitric oxide synthase (eNOS) genes has led to knockout mice that lack these isoforms. These animal models have been useful to study the roles of nitric oxide (NO) in physiologic processes. nNOS knockout mice have enlarged stomachs and defects in the inhibitory junction potential involved in gastrointestinal motility. eNOS knockout mice are hypertensive and lack endothelium-derived relaxing factor activity. When these animals are subjected to models of focal ischemia, the nNOS mutant mice develop smaller infarcts, consistent with a role for nNOS in neurotoxicity following cerebral ischemia. In contrast, eNOS mutant mice develop larger infarcts, and show a more pronounced...

Bi-directional actions of estrogen on the renin-angiotensin system

Palavras-chave: Nitric oxide; Targeted disruption; Gene knockout; Endothelium; Stroke; Atherosclerosis.

Ano: 1999

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1999001100005

Brosnihan,K.B.; Senanayake,P.S.; Li,P.; Ferrario,C.M..

Estrogen stimulates the renin-angiotensin system by augmenting both tissue and circulating levels of angiotensinogen and renin. We show, however, that angiotensin converting enzyme (ACE) activity in the circulation and in tissues is reduced in two animal models of postmenopausal chronic hormone replacement. We observed a reduction of ACE activity in association with a significant increase in plasma angiotensin I (Ang I) and hyperreninemia in ovariectomized monkeys treated with Premarin (conjugated equine estrogen) replacement for 30 months. Plasma angiotensin II (Ang II) levels were not increased in monkeys treated with estrogen, suggesting that the decrease in ACE curtailed the formation of the peptide. The Ang II/Ang I ratio, an in vivo index of ACE...

Antigenic stimulation is more efficient than LPS in inducing nitric oxide production by human mononuclear cells on the in vitro granuloma reaction in schistosomiasis

Palavras-chave: Renin; Angiotensin converting enzyme; Angiotensin peptides; Angiotensin receptors; Bradykinin; Nitric oxide; Kinins; Vasodilation; Hormone replacement.

Ano: 1999

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1999000400001

Oliveira,D.M.; Silva-Teixeira,D.N.; Araújo-Filho,R.; Goes,A.M..

Nitric oxide (NO) is an extremely important and versatile messenger in biological systems. It has been identified as a cytotoxic factor in the immune system, presenting anti- or pro-inflammatory properties under different circumstances. In murine monocytes and macrophages, stimuli by cytokines or lipopolysaccharide (LPS) are necessary for inducing the immunologic isoform of the enzyme responsible for the high-output production of NO, nitric oxide synthase (iNOS). With respect to human cells, however, LPS seems not to stimulate NO production in the same way. Addressing this issue, we demonstrate here that peripheral blood mononuclear cells (PBMC) obtained from schistosomiasis-infected patients and cultivated with parasite antigens in the in vitro granuloma...

Cellular signaling with nitric oxide and cyclic GMP

Palavras-chave: Nitric oxide; LPS; Schistosomiasis infection; In vitro granuloma.

Ano: 1999

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1999001100015

Murad,F..

During the past two decades, nitric oxide signaling has been one of the most rapidly growing areas in biology. This simple free radical gas can regulate an ever growing list of biological processes. In most instances nitric oxide mediates its biological effects by activating guanylyl cyclase and increasing cyclic GMP synthesis. However, the identification of effects of nitric oxide that are independent of cyclic GMP is also growing at a rapid rate. The effects of nitric oxide can mediate important physiological regulatory events in cell regulation, cell-cell communication and signaling. Nitric oxide can function as an intracellular messenger, neurotransmitter and hormone. However, as with any messenger molecule, there can be too much or too little of the...

Anxiolytic effect of methylene blue microinjected into the dorsal periaqueductal gray matter

Palavras-chave: Nitric oxide; Nitric oxide synthase; Guanylyl cyclase; Cell signaling.

Ano: 1999

URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1999001100001

de-Oliveira,R.W.; Guimarães,F.S..

The dorsal periaqueductal gray (DPAG) has been implicated in the behavioral and autonomic expression of defensive reactions. Several results suggest that, along with GABA, glutamate and serotonin, nitric oxide (NO) may play a role in defense reactions mediated by this region. To further investigate this possibility we microinjected methylene blue (MB; 10, 30 or 100 nmol/0.5 µl) into the DPAG of rats submitted to the elevated plus-maze test, an animal model of anxiety. MB has been used as an inhibitor of soluble guanylate cyclase (sGC) to demonstrate cGMP-mediated processes, and there is evidence that NO may exert its biological effects by binding to the heme part of guanylate cyclase, causing an increase in cGMP levels. The results showed that MB (30 nmol)...