Effect of nitric oxide and potassium channel agonists and inhibitors on basilar artery diameter

1997 ◽  
Vol 272 (1) ◽  
pp. H256-H262 ◽  
Author(s):  
C. G. Sobey ◽  
F. M. Faraci
Keyword(s):  
Nitric Oxide ◽  
Sodium Nitroprusside ◽  
Basilar Artery ◽  
Selective Inhibitor ◽  
No Production ◽  
No Donor ◽  
K Channels ◽  
Cranial Window ◽  
Endogenous Production ◽  
Direct Activator

The first goal of this study was to examine the hypothesis that dilatation of the basilar artery in response to activation of ATP-sensitive K+ channels is mediated by nitric oxide (NO). Diameter of the basilar artery (209 +/- 5 microns, mean +/- SE) was measured using a cranial window in anesthetized rats. Aprikalim (a direct activator of ATP-sensitive K+ channels) dilated the basilar artery under control conditions. Inhibition of endogenous NO production with NG-nitro-L-arginine (L-NNA, 10(-4) M) did not alter responses to aprikalim. The second goal was to determine whether vasodilatation in response to NO is dependent on activation of calcium-activated K+ channels. Tetraethylammonium (TEA, 10(-3) M), an inhibitor of calcium-activated K+ channels, did not affect dilator responses to sodium nitroprusside (an NO donor) under control conditions. Responses to nitroprusside (10(-8) and 10(-7) M) were augmented more than twofold during application of L-NNA. In the presence of L-NNA, the augmented portion of the response to nitroprusside was inhibited by TEA and iberiotoxin (5 x 10(-8) M, a highly selective inhibitor of calcium-activated K+ channels), but it was not inhibited by glibenclamide (10(-6) M), an inhibitor of ATP-sensitive K+ channels. These findings suggest that dilator responses of the basilar artery to an activator of ATP-sensitive potassium channels are not mediated by NO. Calcium-activated K+ channels may not normally contribute to dilator responses of the basilar artery to nitroprusside. The effects of TEA and iberiotoxin suggest that when endogenous production of NO is inhibited, sodium nitroprusside causes the opening of calcium-activated K+ channels, contributing to an augmented vasodilator response.

Effect of norepinephrine on rat basilar artery in vivo

1993 ◽  
Vol 264 (1) ◽  
pp. H178-H182 ◽  
Author(s):  
T. Kitazono ◽  
F. M. Faraci ◽  
D. D. Heistad
Keyword(s):  
Basilar Artery ◽  
Selective Inhibitor ◽  
K Channels ◽  
Cranial Window ◽  
Relaxing Factor ◽  
Endothelium Derived Relaxing Factor ◽  
Oxide Synthase ◽  
Dependent Mechanism ◽  
Direct Activator

In anesthetized rats, we used a cranial window to examine effects of topical norepinephrine on diameter of the basilar artery in vivo. Topical application of norepinephrine increased the diameter of the basilar artery. NG-nitro-L-arginine methyl ester, an inhibitor of nitric oxide synthase, inhibited vasodilatation to acetylcholine but did not attenuate dilator responses to norepinephrine. Indomethacin also did not attenuate vasodilatation in response to norepinephrine. Dilatation of the basilar artery to norepinephrine was inhibited by propranolol and the beta 1-antagonist atenolol but not by the beta 2-antagonist butoxamine. Thus dilatation of the basilar artery in response to norepinephrine is produced by activation of beta 1-receptors and is not mediated by endothelium-derived relaxing factor or prostanoids. Glibenclamide, a selective inhibitor of ATP-sensitive K+ channels, partially inhibited vasodilatation in response to norepinephrine. Forskolin, a direct activator of adenylate cyclase, also increased the diameter of the basilar artery, and glibenclamide attenuated the dilatation. Thus dilatation of rat basilar artery in response to norepinephrine is mediated, in part, by activation of ATP-sensitive K+ channels, and activation of these K+ channels may be achieved by an adenosine 3',5'-cyclic monophosphate-dependent mechanism.

scholarly journals The Nitric Oxide (NO) Donor Sodium Nitroprusside (SNP) and Its Potential for the Schizophrenia Therapy: Lights and Shadows

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3196
Author(s):  
Elli Zoupa ◽  
Nikolaos Pitsikas
Keyword(s):  
Nitric Oxide ◽  
Sodium Nitroprusside ◽  
Cognitive Deficits ◽  
Negative Symptoms ◽  
Mental Disease ◽  
No Production ◽  
No Donor ◽  
No Donors ◽  
Worldwide Population ◽  
The Brain

Schizophrenia is a severe psychiatric disorder affecting up to 1% of the worldwide population. Available therapy presents different limits comprising lack of efficiency in attenuating negative symptoms and cognitive deficits, typical features of schizophrenia and severe side effects. There is pressing requirement, therefore, to develop novel neuroleptics with higher efficacy and safety. Nitric oxide (NO), an intra- and inter-cellular messenger in the brain, appears to be implicated in the pathogenesis of schizophrenia. In particular, underproduction of this gaseous molecule is associated to this mental disease. The latter suggests that increment of nitrergic activity might be of utility for the medication of schizophrenia. Based on the above, molecules able to enhance NO production, as are NO donors, might represent a class of compounds candidates. Sodium nitroprusside (SNP) is a NO donor and is proposed as a promising novel compound for the treatment of schizophrenia. In the present review, we intended to critically assess advances in research of SNP for the therapy of schizophrenia and discuss its potential superiority over currently used neuroleptics.

The Role of Nitric Oxide in Regulation of Red Blood Cell Deformability.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 3730-3730
Author(s):  
Xiaojun He ◽  
Ivan Azarov ◽  
Beth Gordon ◽  
Daniel B. Kim-Shapiro ◽  
Samir K. Ballas
Keyword(s):  
Nitric Oxide ◽  
Sodium Nitroprusside ◽  
Electron Paramagnetic Resonance Spectroscopy ◽  
Flow Channel ◽  
Resonance Spectroscopy ◽  
No Production ◽  
Cell Deformability ◽  
No Donor ◽  
Physiol Heart Circ ◽  
Rbc Deformability

Abstract Nitric Oxide (NO) has been suggested to modulate the deformability of red blood cells (RBCs). Bor-Kucukatay (Bor-Kucukatay et al. Am J Physiol Heart Circ Physiol284: H1577, 2003) found that cells incubated with 1 μM of the NO donor sodium nitroprusside lead to a small but significant increase RBC deformability as measured by ektacytometry. However, no significant effect was seen at lower or higher concentrations of sodium nitroprusside or for any concentration of another NO donor, diethylenetriamine NONOate. Kleinbongard (Kleinbongard et al. Blood10; 3992, 2005) found large increases in red cell deformability as a function of added arginine (the substrate for Nitric Oxide Synthase) by measuring the flow rate through filters. On the other hand, using cell aspiration techniques, Bateman (Bateman et al. Am J Physiol Heart Circ Physiol 280; H2848 H2001) found that NO production during sepsis causes a decrease in RBC deformability. Clearly more work is needed to determine the effects of NO on RBC deformability. The present work was undertaken to further investigate the effect of NO on normal and sickle RBC deformability. ProLi NONOate, arginine, and nitrite (which can be reduced to NO by hemoglobin (Hb), were incubated with blood at various concentrations over a period of 2 hours. Nitrosyl Hb and MetHb formed due to the interaction between NO and RBCs were quantified by electron paramagnetic resonance spectroscopy. The deformability was measured using a flow channel laser diffraction similar to ektacytometry (Huang et al. Am J Hematol67; 151, 2001, Biophys J85; 2374, 2003) with a stress range from 0 to 1,000 Pa. Diffraction patterns produced by deformed cells were analyzed by Matlab®. The deformability coefficients were compared to the control (n=6 per experiment condition). Our results suggested that ProLi NONOate did not significantly effect the deformability of normal RBCs. In a single case, ProLi NONOate improved the deformability of poorly deformable sickle red cells and this result is being studied further. Using our flow channel assay, we did not find any significant affects of arginine on RBC deformability. In addition, our studies involving nitrite, performed under both oxygenated and deoxygenated conditions, suggested that nitrite has no significant effect on RBC deformability. In summary, NO didn’t significantly affect the deformability of normal RBCs, and its potential effects on sickle RBCs needs to be further investigated.

Abstract 2305: Endothelin-1 Alters Nitric Oxide-Dependent Cerebrovascular Responses by Modulating The Phosphorylation State of eNOS via Rho Kinase

Stroke ◽  
2012 ◽  
Vol 43 (suppl_1) ◽  
Author(s):  
Giuseppe Faraco ◽  
Joseph Anrather ◽  
Costantino Iadecola
Keyword(s):  
Nitric Oxide ◽  
Rho Kinase ◽  
Smooth Muscle Relaxation ◽  
No Production ◽  
Rock Inhibitor ◽  
No Donor ◽  
Doppler Flowmetry ◽  
Phosphorylation State ◽  
Endothelin 1 ◽  
Cranial Window

Hypertension (HTN) alters vital homeostatic mechanisms regulating cerebral blood flow (CBF) and increases the risk of stroke and dementia. HTN exerts some of its damaging effects by counteracting the beneficial vascular actions of nitric oxide (NO). The potent vasoconstrictor endothelin-1 (ET1) has been implicated in the pathogenesis of HTN, but its role in the cerebrovascular effects of HTN is unknown. We examined whether ET1 disrupts CBF regulation. CBF (laser-Doppler flowmetry) was assessed in the somatosensory cortex in anesthetized male C57Bl/6 mice (n=5/group) equipped with a cranial window. ET1 (35 pmol/kg/min; i.v. for 45 min) increased mean arterial pressure from 72±4 to 99±6 mmHg (p<0.05), without reducing resting CBF (p>0.05). However, ET1 attenuated the CBF increase produced by neocortical application of the endothelium-dependent vasodilator acetylcholine (ACh; -37±1%; p<0.05) and by whisker stimulation (-31±1%; p<0.05), responses dependent on NO. The CBF response to adenosine was intact (p>0.05) indicating that ET1 did not act by compromising smooth muscle relaxation. The effects of ET1 were prevented by the ET type A (ET A ) receptor antagonist BQ123 (1µM; p<0.05), by the Rho kinase (ROCK) inhibitor Y27632 (1 µM; p<0.05), but not by the ET B antagonist BQ788 (100nM; p>0.05). ET-1 did not affect the CBF increase produced by the NO donor SNAP and did not increase free radicals, suggesting that ET-1 did not act by reducing NO vasoactivity or bioavailability. However, in brain endothelial cell cultures ET1 (10-100nM) attenuated the NO production induced by ACh (-49±4% at 50nM; p<0.05), an effect blocked by BQ123 and Y27632. ET1 increased eNOS phosphorylation at Thr495, which inhibits eNOS, and reduced phosphorylation at Ser1177, which activates eNOS, effects blocked by Y27632. These findings, collectively, suggest that ET1 alters key regulatory mechanisms of the cerebral circulation by modulating the phosphorylation state of eNOS via ROCK. The resulting downregulation of eNOS activity is responsible for the neurovascular dysregulation induced by ET1. ET A receptors may be a valuable target to counteract the deleterious cerebrovascular actions of HTN.

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.

scholarly journals Hydrogen Sulfide Increases Nitric Oxide Production and Subsequent S-Nitrosylation in Endothelial Cells

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Ping-Ho Chen ◽  
Yaw-Syan Fu ◽  
Yun-Ming Wang ◽  
Kun-Han Yang ◽  
Danny Ling Wang ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Endothelial Cells ◽  
Hydrogen Sulfide ◽  
Protein Kinase ◽  
Fluorescent Probe ◽  
Acid Methyl Ester ◽  
High Specificity ◽  
Protein S ◽  
No Production ◽  
No Donor

Hydrogen sulfide (H2S) and nitric oxide (NO), two endogenous gaseous molecules in endothelial cells, got increased attention with respect to their protective roles in the cardiovascular system. However, the details of the signaling pathways between H2S and NO in endothelia cells remain unclear. In this study, a treatment with NaHS profoundly increased the expression and the activity of endothelial nitric oxide synthase. Elevated gaseous NO levels were observed by a novel and specific fluorescent probe, 5-amino-2-(6-hydroxy-3-oxo-3H-xanthen-9-yl)benzoic acid methyl ester (FA-OMe), and quantified by flow cytometry. Further study indicated an increase of upstream regulator for eNOS activation, AMP-activated protein kinase (AMPK), and protein kinase B (Akt). By using a biotin switch, the level of NO-mediated protein S-nitrosylation was also enhanced. However, with the addition of the NO donor, NOC-18, the expressions of cystathionine-γ-lyase, cystathionine-β-synthase, and 3-mercaptopyruvate sulfurtransferase were not changed. The level of H2S was also monitored by a new designed fluorescent probe, 4-nitro-7-thiocyanatobenz-2-oxa-1,3-diazole (NBD-SCN) with high specificity. Therefore, NO did not reciprocally increase the expression of H2S-generating enzymes and the H2S level. The present study provides an integrated insight of cellular responses to H2S and NO from protein expression to gaseous molecule generation, which indicates the upstream role of H2S in modulating NO production and protein S-nitrosylation.

Maturational changes in the regulation of pulmonary vascular tone by nitric oxide in neonatal rats

2007 ◽  
Vol 293 (5) ◽  
pp. L1261-L1270 ◽  
Author(s):  
Louis G. Chicoine ◽  
Michael L. Paffett ◽  
Mark R. Girton ◽  
Matthew J. Metropoulus ◽  
Mandar S. Joshi ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Guanylyl Cyclase ◽  
Vascular Tone ◽  
Age Groups ◽  
Soluble Guanylyl Cyclase ◽  
No Production ◽  
Sprague Dawley ◽  
No Donor ◽  
Early Postnatal Development ◽  
Old Rats

Nitric oxide (NO) is an important regulator of vasomotor tone in the pulmonary circulation. We tested the hypothesis that the role NO plays in regulating vascular tone changes during early postnatal development. Isolated, perfused lungs from 7- and 14-day-old Sprague-Dawley rats were studied. Baseline total pulmonary vascular resistance (PVR) was not different between age groups. The addition of KCl to the perfusate caused a concentration-dependent increase in PVR that did not differ between age groups. However, the nitric oxide synthase (NOS) inhibitor Nω-nitro-l-arginine augmented the K+-induced increase in PVR in both groups, and the effect was greater in lungs from 14-day-old rats vs. 7-day-old rats. Lung levels of total endothelial, inducible, and neuronal NOS proteins were not different between groups; however, the production rate of exhaled NO was greater in lungs from 14-day-old rats compared with those of 7-day-old rats. Vasodilation to 0.1 μM of the NO donor spermine NONOate was greater in 14-day lungs than in 7-day lungs, and lung levels of both soluble guanylyl cyclase and cGMP were greater at 14 days than at 7 days. Vasodilation to 100 μM of the cGMP analog 8-(4-chlorophenylthio)guanosine-3′,5′-cyclic monophosphate was greater in 7-day lungs than in 14-day lungs. Our results demonstrate that the pulmonary vascular bed depends more on NO production to modulate vascular tone at 14 days than at 7 days of age. The observed differences in NO sensitivity may be due to maturational increases in soluble guanylyl cyclase protein levels.

scholarly journals Role of Nitric Oxide in Regulation of Brain Stem Circulation during Hypotension

1997 ◽  
Vol 17 (10) ◽  
pp. 1089-1096 ◽  
Author(s):  
Kazunori Toyoda ◽  
Kenichiro Fujii ◽  
Setsuro Ibayashi ◽  
Tetsuhiko Nagao ◽  
Takanari Kitazono ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Brain Stem ◽  
Topical Application ◽  
Basilar Artery ◽  
Group Versus ◽  
Control Group ◽  
Cranial Window ◽  
Severe Hypotension ◽  
The Brain

We tested the hypothesis that nitric oxide (NO) plays a role in CBF autoregulation in the brain stem during hypotension. In anesthetized rats, local CBF to the brain stem was determined with laser-Doppler flowmetry, and diameters of the basilar artery and its branches were measured through an open cranial window during stepwise hemorrhagic hypotension. During topical application of 10−5 mol/L and 10−4 mol/L Nω-nitro-L-arginine (L-NNA), a nonselective inhibitor of nitric oxide synthase (NOS), CBF started to decrease at higher steps of mean arterial blood pressure in proportion to the concentration of L-NNA in stepwise hypotension (45 to 60 mm Hg in the 10−5 mol/L and 60 to 75 mm Hg in the 10−4 mol/L L-NNA group versus 30 to 45 mm Hg in the control group). Dilator response of the basilar artery to severe hypotension was significantly attenuated by topical application of L-NNA (maximum dilatation at 30 mm Hg: 16 ± 8% in the 10−5 mol/L and 12 ± 5% in the 10−4 mol/L L-NNA group versus 34 ± 4% in the control group), but that of the branches was similar between the control and L-NNA groups. Topical application of 10−5 mol/L 7-nitro indazole, a selective inhibitor of neuronal NOS, did not affect changes in CBF or vessel diameter through the entire pressure range. Thus, endothelial but not neuronal NO seems to take part in the regulation of CBF to the the brain stem during hypotension around the lower limits of CBF autoregulation. The role of NO in mediating dilatation in response to hypotension appears to be greater in large arteries than in small ones.

Nitric oxide increases fluid extravasation from the splenic circulation of the rat

2001 ◽  
Vol 280 (4) ◽  
pp. R959-R967 ◽  
Author(s):  
Peter S. Andrew ◽  
Yiming Deng ◽  
Richard Sultanian ◽  
Susan Kaufman
Keyword(s):  
Nitric Oxide ◽  
Sodium Nitroprusside ◽  
Lymphatic System ◽  
Resistance Arteries ◽  
No Donor ◽  
Fluid Extravasation ◽  
Resistance Vessels ◽  
Blood Inflow ◽  
The Difference ◽  
Arteries And Veins

We hypothesized that nitric oxide (NO) contributes to intrasplenic fluid extravasation by inducing greater relaxation in splenic resistance arteries than veins such that intrasplenic microvascular pressure (PC) rises. Fluid efflux was estimated by measuring the difference between splenic blood inflow and outflow. Intrasplenic infusion of the NO donor S-nitroso- N-acetylpenicillamine (SNAP) (0.3 μg · 10 μl−1 · min−1) caused a significant increase in intrasplenic fluid efflux (baseline: 0.8 ± 0.4 ml/min, n = 10 vs. peak rise during SNAP infusion: 1.3 ± 0.4 ml/min, n = 10; P < 0.05). Intrasplenic PC was measured in the isolated, blood-perfused rat spleen. Intrasplenic infusion of SNAP (0.1 μg · 10 μl−1 · min−1) caused a significant increase in PC (saline: 10.9 ± 0.2 mmHg, n = 3 vs. SNAP: 12.2 ± 0.2 mmHg, n = 3; P < 0.05). Vasoreactivity of preconstricted splenic resistance vessels to sodium nitroprusside (SNP) (1 × 10−12-1 × 10−4 M) and SNAP (1 × 10−10-3 × 10−4 M) was investigated with the use of a wire myograph system. Significantly greater relaxation of arterioles than of venules occurred with both SNP (%maximal vasorelaxation: artery 96 ± 2.3, n = 9 vs. vein 26 ± 1.9, n = 10) and SNAP (%maximal vasorelaxation: artery 50 ± 3.5, n = 11 vs. vein 32 ± 1.7, n = 8). These results are consistent with our proposal that differential vasoreactivity of splenic resistance arteries and veins to NO elevates intrasplenic PC and increases fluid extravasation into the systemic lymphatic system.

Caspase Activation Is Required for Nitric Oxide–Mediated, CD95(APO-1/Fas)–Dependent and Independent Apoptosis in Human Neoplastic Lymphoid Cells

Blood ◽  
1998 ◽  
Vol 91 (11) ◽  
pp. 4311-4320 ◽  
Author(s):  
Katerina Chlichlia ◽  
Marcus E. Peter ◽  
Marian Rocha ◽  
Carsten Scaffidi ◽  
Mariana Bucur ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Present Report ◽  
Lymphoid Cells ◽  
Jurkat Cells ◽  
Target Cells ◽  
No Production ◽  
No Donor ◽  
Synthase Inhibitor ◽  
Inhibitor Of Protein Synthesis

Abstract Nitric oxide (NO), an important effector molecule involved in immune regulation and host defense, was shown to induce apoptosis in lymphoma cells. In the present report the NO donor glycerol trinitrate was found to induce apoptosis in Jurkat cells that are sensitive to CD95-mediated kill. In contrast, a CD95-resistant Jurkat subclone showed substantial protection from apoptosis after exposure to NO. NO induced mRNA expression of CD95 (APO-1/Fas) and TRAIL/APO-2 ligands. Moreover, NO triggered apoptosis in freshly isolated human leukemic lymphocytes which were also sensitive to anti-CD95 treatment. The ability of NO to induce apoptosis was completely blocked by a broad-spectrum ICE (interleukin-1β converting enzyme)-protease/caspase inhibitor and correlated with FLICE/caspase-8 activation. This activation was abrogated in some neoplastic lymphoid cells but not in others by the inhibitor of protein synthesis cycloheximide. Our results were confirmed using an in vitro experimental model of coculture of human lymphoid target cells with activated bovine endothelial cells generating NO as effectors. Furthermore, the inhibition of endogenous NO production with the inducible NO synthase inhibitor NG-monomethyl-L-arginine caused a complete abrogation of the apoptotic effect. Our data provide evidence that NO-induced apoptosis in human neoplastic lymphoid cells strictly requires activation of caspases, in particular FLICE, the most CD95 receptor-proximal caspase. Depending on the cell line tested this activation required or was independent of the CD95 receptor/ligand system.

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