Role of nitric oxide on in vitro human eosinophil migration11Abbreviations: AMT, 2-amino-5,6-dihydro-6-methyl-4H-1,3-thiazine; fMLP, N-formyl-methionyl-leucyl-phenylalanine; cGMP, db-cGMP, dibutyryl cyclic GMP; d-NAME, Nω-nitro-d-arginine methyl ester; l-NAME, Nω-nitro-l-arginine methyl ester; l-NIL, l-N6-(1-iminoethyl) lysine; NO, nitric oxide; NOS, nitric oxide synthase; ODQ, 1H-[1,2,4]-oxidiazolo[4,3-a] quinoxalin-1-one; and TRIM, 1-(2-trifluoromethylphenyl) imidazole.

2001 ◽  
Vol 62 (10) ◽  
pp. 1417-1421 ◽  
Author(s):  
Sara M. Thomazzi ◽  
Heloisa H.A. Ferreira ◽  
Nicola Conran ◽  
Gilberto De Nucci ◽  
Edson Antunes
Keyword(s):  
Nitric Oxide ◽  
Methyl Ester ◽  
Nitric Oxide Synthase ◽  
Cyclic Gmp ◽  
Human Eosinophil ◽  
Oxide Synthase

Endothelium-dependent vasodilation of cerebral arteries is altered with simulated microgravity through nitric oxide synthase and EDHF mechanisms

2006 ◽  
Vol 101 (1) ◽  
pp. 348-353 ◽  
Author(s):  
Rhonda D. Prisby ◽  
M. Keith Wilkerson ◽  
Elke M. Sokoya ◽  
Robert M. Bryan ◽  
Emily Wilson ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Methyl Ester ◽  
Nitric Oxide Synthase ◽  
Cerebral Perfusion ◽  
Simulated Microgravity ◽  
Cerebral Arteries ◽  
Caveolin 1 ◽  
Fluid Shifts ◽  
Oxide Synthase

Cephalic elevations in arterial pressure associated with microgravity and prolonged bed rest alter cerebrovascular autoregulation in humans. Using the head-down tail-suspended (HDT) rat to chronically induce headward fluid shifts and elevate cerebral artery pressure, previous work has likewise shown cerebral perfusion to be diminished. The purpose of this study was to test the hypothesis that 2 wk of HDT reduces cerebral artery vasodilation. To test this hypothesis, dose-response relations for endothelium-dependent (2-methylthioadenosine triphosphate and bradykinin) and endothelium-independent (nitroprusside) vasodilation were determined in vitro in middle cerebral arteries (MCAs) from HDT and control rats. All in vitro measurements were done in the presence and absence of the nitric oxide synthase inhibitor NG-nitro-l-arginine methyl ester (10−5 M) and cyclooxygenase inhibitor indomethacin (10−5 M). MCA caveolin-1 protein content was measured by immunoblot analysis. Endothelium-dependent vasodilation to 2-methylthioadenosine triphosphate and bradykinin were both lower in MCAs from HDT rats. These lower vasodilator responses were abolished with NG-nitro-l-arginine methyl ester but were unaffected by indomethacin. In addition, HDT was associated with lower levels of MCA caveolin-1 protein. Endothelium-independent vasodilation was not altered by HDT. These results indicate that chronic cephalic fluid shifts diminish endothelium-dependent vasodilation through alterations in the endothelial nitric oxide synthase signaling mechanism. Such decrements in endothelium-dependent vasodilation of cerebral arteries could contribute to the elevations in cerebral vascular resistance and reductions in cerebral perfusion that occur after conditions of simulated microgravity in HDT rats.

Role of inducible nitric oxide synthase in the regulation of leucocyte recruitment

2000 ◽  
Vol 100 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Michael J. HICKEY
Keyword(s):  
Nitric Oxide ◽  
Endothelial Cells ◽  
Nitric Oxide Synthase ◽  
Cell Types ◽  
Adhesive Interactions ◽  
Oxide Synthase ◽  
Leucocyte Recruitment

Constitutively produced nitric oxide released by endothelial cells has been shown to act as an endogenous agent which inhibits the rolling and adhesion of leucocytes in the microcirculation. However, during various types of inflammation, expression of the inducible form of nitric oxide synthase (iNOS) can dramatically increase the amount of nitric oxide present in tissues. Furthermore, as iNOS can be expressed by a wide variety of cell types, the distribution of nitric oxide is likely to be altered relative to that in unstimulated tissue. Under these conditions, it is less well understood whether iNOS-derived nitric oxide retains the anti-adhesive capabilities of constitutively produced nitric oxide. This review summarizes work done to examine this issue. Three main approaches have been used. In vitro studies have examined the role of iNOS in adhesive interactions between stimulated endothelial cells and leucocytes, providing evidence of an anti-adhesive effect of iNOS. In addition, the role of iNOS has been examined in vivo in animal models of inflammation using pharmacological iNOS inhibitors. These experiments were extended by the advent of the iNOS-deficient (iNOS-/-) mouse. Intravital microscopy studies of these mice have indicated that, under conditions of low-dose endotoxaemia, iNOS-derived nitric oxide can inhibit leucocyte rolling and adhesion. The potential mechanisms for these effects are discussed. In contrast, several other studies have observed either no effect or an enhancing effect of iNOS on inflammatory leucocyte recruitment. Taken together, these studies suggest that the importance of iNOS in modulating leucocyte recruitment can vary according to the type of inflammatory response.

Dilation of rat diaphragmatic arterioles by flow and hypoxia: roles of nitric oxide and prostaglandins

1999 ◽  
Vol 86 (5) ◽  
pp. 1644-1650 ◽  
Author(s):  
Michael E. Ward
Keyword(s):  
Nitric Oxide ◽  
Methyl Ester ◽  
Nitric Oxide Synthase ◽  
Concurrent Treatment ◽  
Nitric Oxide Release ◽  
Luminal Flow ◽  
Hypoxic Vasodilation ◽  
Oxide Synthase ◽  
Endothelial Nitric Oxide

The in vitro responses to ACh, flow, and hypoxia were studied in arterioles isolated from the diaphragms of rats. The endothelium was removed in some vessels by low-pressure air perfusion. In endothelium-intact arterioles, pressurized to 70 mmHg in the absence of luminal flow, ACh (10−5 M) elicited dilation (from 103 ± 10 to 156 ± 13 μm). The response to ACh was eliminated by endothelial ablation and by the nitric oxide synthase antagonists N G-nitro-l-arginine (l-NNA; 10−5 M) and N G-nitro-l-arginine methyl ester (l-NAME, 10−5 M) but not by indomethacin (10−5 M). Increases in luminal flow (5–35 μl/min in 5 μl/min steps) at constant distending pressure (70 mmHg) elicited dilation (from 98 ± 8 to 159 ± 12 μm) in endothelium-intact arterioles. The response to flow was partially inhibited byl-NNA,l-NAME, and indomethacin and eliminated by endothelial ablation and by concurrent treatment withl-NAME and indomethacin. The response to hypoxia was determined by reducing the periarteriolar[Formula: see text] from 100 to 25–30 Torr by changing the composition of the gas used to bubble the superfusing solution. Hypoxia elicited dilation (from 110 ± 9 to 165 ± 12 μm) in endothelium-intact arterioles but not in arterioles from which the endothelium had been removed. Hypoxic vasodilation was eliminated by treatment with indomethacin and was not affected byl-NAME orl-NNA. In rat diaphragmatic arterioles, the response to ACh is dependent on endothelial nitric oxide release, whereas the response to hypoxia is mediated by endothelium-derived prostaglandins. Flow-dilation requires that both nitric oxide and cyclooxygenase pathways be intact.

Evidence that nitric oxide synthase is involved in progesterone-induced acrosomal exocytosis in mouse spermatozoa

1997 ◽  
Vol 9 (4) ◽  
pp. 433 ◽  
Author(s):  
María Beléen Herrero ◽  
J. Marcelo Viggiano ◽  
Silvina Pérez Martínez ◽  
Martha F. de Gimeno
Keyword(s):  
Nitric Oxide ◽  
Methyl Ester ◽  
Nitric Oxide Synthase ◽  
No Synthase ◽  
Nitric Oxide Donor ◽  
Mouse Sperm ◽  
Acrosomal Exocytosis ◽  
Oxide Synthase ◽  
Spermine Nonoate

In a recent work, we detected nitric oxide synthase (NO synthase) in the acrosome and tail of mouse and human spermatozoa by an immunofluorescence technique. Also, NO-synthase inhibitors added during sperm capacitationin vitro reduced the percentage of oocytes fertilized in vitro, suggesting a role for NO synthase in sperm function. Therefore, in the present study the effect of three NO-synthase inhibitors, NG-nitro-L-arginine methyl ester (L-NAME), NG-nitro-D-arginine methyl ester (D-NAME) and L-NG-nitro-arginine (NO2-arg), and of a nitric oxide donor, spermine-NONOate, on the progesterone-induced acrosome reaction of mouse sperm was examined. NO-synthase inhibitors were added at 0, 60 or 90 min during capacitation; at 120 min, mouse epididymal spermatozoa were exposed to 15 µM progesterone for another 15 min. In another set of experiments, different concentrations of spermine-NONOate were added to capacitated spermatozoa for 15 min; in these experiments, progesterone was not included. NO2-arg and L-NAME blocked progesterone-induced exocytosis regardless of the time at which these inhibitors were added. Moreover, D-NAME did not inhibit exocytosis. In contrast, spermine-NONOate stimulated the acrosomal exocytosis in vitro directly. These results provide evidence that mouse sperm NO synthase participates in the progesterone-induced acrosome reactionin vitro and that nitric oxide induces this event.

scholarly journals Cerebral Blood Flow during Hypoxemia and Hemodilution in Rabbits: Different Roles for Nitric Oxide?

1997 ◽  
Vol 17 (12) ◽  
pp. 1319-1325 ◽  
Author(s):  
Michael M. Todd ◽  
Stella Farrell ◽  
Bo Wu
Keyword(s):  
Nitric Oxide ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Methyl Ester ◽  
Nitric Oxide Synthase ◽  
Cyclic Gmp ◽  
Radioactive Microspheres ◽  
Cranial Window ◽  
Oxide Synthase ◽  
Nitric Oxide Synthase Activity

Hypoxemia and anemia are associated with increased CBF, but the mechanisms that link the changes in Pao2 or arterial O2 content (Cao2) with CBF are unclear. These experiments were intended to examine the contribution of nitric oxide. Cao2 in pentobarbital-anesthetized rabbits was reduced to approximately 6.5 mL O2/dL by hypoxemia (Pao2 approximately 24 to 26 mm Hg) or hemodilution with hetastarch (hematocrit approximately 14% to 15%). Animals with normal Cao2 (approximately 17.5 to 18 mL O2/dL) served as controls. In part I, each animal was given 3, 10, and 30 mg/kg Nω-nitro-l-arginine methyl ester (l-NAME) intravenously (total 43 mg/kg) to inhibit production of nitric oxide. Forebrain CBF was measured with radioactive microspheres approximately 15 to 20 minutes after each dose. Baseline CBF was greater in hypoxemic rabbits (111 ± 31 mL·100 g−1·min−1, mean ± SD) than in hemodiluted (70 ± 22 mL·100 g−1·min−1) or control animals (39 ± 12 mL·100 g−1·min−1). l-NAME (which reduced brain tissue nitric oxide synthase activity by approximately 65%) reduced CBF in hypoxemic animals to 80 ± 23 mL·100 g−1·min−1 ( P < 0.0001), but had no significant effect on CBF in either anemic or control animals. In four additional rabbits, further hemodilution to a Cao2 of approximately 3.5 mL O2/dL increased baseline CBF to 126 ± 21 mL·100 g−1·min−1, but again there was no effect of l-NAME. In part II, animals were anesthetized as above, and a closed cranial window was prepared. The cyclic GMP (cGMP) content of the artificial CSF superfusate was measured under baseline conditions, and then after the reduction of Cao2 to approximately 6.5 mL O2/dL by either hypoxemia or hemodilution. Concentrations of cGMP did not change during either control conditions or after hemodilution. However, cGMP increased significantly with the induction of hypoxemia. The cGMP increase in hypoxemic animals could be blocked with l-NAME. These results suggest that nitric oxide plays some role in hypoxemic vasodilation, but not during hemodilution.

scholarly journals Role of cyclic GMP on inhibition by nitric oxide donors of human eosinophil chemotaxis in vitro

2004 ◽  
Vol 141 (4) ◽  
pp. 653-660 ◽  
Author(s):  
Sara M Thomazzi ◽  
Juliana Moreira ◽  
Sisi Marcondes ◽  
Gilberto De Nucci ◽  
Edson Antunes
Keyword(s):  
Nitric Oxide ◽  
Cyclic Gmp ◽  
Nitric Oxide Donors ◽  
Human Eosinophil ◽  
Eosinophil Chemotaxis

scholarly journals Modulation of glomerular arteriolar tone by nitric oxide synthase inhibitors.

1993 ◽  
Vol 4 (5) ◽  
pp. 1127-1132
Author(s):  
R M Edwards ◽  
W Trizna
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Inhibitory Effect ◽  
Lumen Diameter ◽  
Nitric Oxide Synthase Inhibitors ◽  
Afferent Arterioles ◽  
Arteriolar Tone ◽  
Oxide Synthase

The inhibition of nitric oxide production has been shown to reduce RBF. The effects of the nitric oxide synthase inhibitors, N omega-nitro-L-arginine and NG-monomethyl-L-arginine, on afferent and efferent arterioles isolated from rabbit kidneys were examined. Under basal conditions, N omega-nitro-L-arginine (10(-7) to 10(-3) M) had no effect on efferent arteriole lumen diameter but caused a 40% decrease in the lumen diameter of afferent arterioles. In afferent and efferent arterioles precontracted with norepinephrine, N omega-nitro-L-arginine and NG-monomethyl-L-arginine (3 x 10(-4) M) markedly attenuated the vasorelaxant effects of the endothelium-dependent vasodilator acetylcholine. In both arterioles, the inhibitory effect of N omega-nitro-L-arginine on acetylcholine-induced relaxation could be reversed by L- but not D-arginine (10(-3) M). However, N omega-nitro-L-arginine had no effect on the relaxation produced by the endothelium-independent vasodilators prostaglandin E2 (afferent) and dopamine (efferent). These observations demonstrate that under the in vitro conditions used in this study, afferent arterioles but not efferent arterioles synthesize and release nitric oxide in the basal state. However, both arterioles release nitric oxide in response to an endothelium-dependent vasodilator. The results of this study provide further evidence for an important role of nitric oxide in the regulation of renal hemodynamics.

scholarly journals Role of Sex Hormones and Their Receptors on Gastric Nrf2 and Neuronal Nitric Oxide Synthase Function in an Experimental Hyperglycemia Model

2020 ◽  
Author(s):  
Jeremy Sprouse ◽  
Chethan Sampath ◽  
PANDU GANGULA
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Sex Hormones ◽  
Hormone Receptors ◽  
Neuronal Nitric Oxide Synthase ◽  
Nitrite Production ◽  
Oxide Synthase ◽  
Nnos Expression

Abstract Background: Gastroparesis, a condition of abnormal gastric emptying, is most commonly observed in diabetic women. To date, the role of ovarian hormones and/or gastric hormone receptors on regulating nitrergic-mediated gastric motility remains inconclusive. Aim: The purpose of this study is to investigate whether sex hormones/their receptors can attenuate altered Nuclear factor (erythroid-derived 2)-like 2 (Nrf2), neuronal Nitric Oxide Synthase (nNOS) expression and nitrergic relaxation in gastric neuromuscular tissues exposed to in-vitro hyperglycemia (HG). Methods: Gastric neuromuscular sections from adult female C57BL/6J mice were incubated in normoglycemic (NG, 5mM) or hyperglycemic (30 mM or 50 mM) conditions in the presence or absence of selective estrogen receptor (ER) agonists (ERα /PPT or ERβ: DPN); or non-selective sex hormone receptor antagonists (ER/ICI 182,780, or progesterone receptor (PR)/ RU486) for 48 hours. mRNA, protein expression and nitrergic relaxation of circular gastric neuromuscular strips were assessed. Results: Our findings in HG, compared to NG, demonstrate a significant reduction in ER, Nrf2, and nNOS expression in gastric specimens. In addition, in-vitro treatment with sex hormones and/or their agonists significantly (*p<0.05) restored Nrf2/nNOSα expression and total nitrite production. Conversely, ER, but not PR, antagonist significantly reduced Nrf2/nNOSα expression and nitrergic relaxation. Conclusions: Our data suggest that ER’s can regulate nitrergic function by improving Nrf2/nNOS expression in experimental hyperglycemia.

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