Redox variants of NO (NO· and HNO) elicit vasorelaxation of resistance arteries via distinct mechanisms

2009 ◽  
Vol 296 (5) ◽  
pp. H1274-H1280 ◽  
Author(s):  
Joanne L. Favaloro ◽  
Barbara K. Kemp-Harper
Keyword(s):  
Vascular Tone ◽  
Soluble Guanylate Cyclase ◽  
Mesenteric Arteries ◽  
Resistance Arteries ◽  
Angeli's Salt ◽  
Voltage Dependent ◽  
Vasorelaxant Activity ◽  
Electron Reduction ◽  
Resting Tone ◽  
Redox Forms

The free radical form of nitric oxide (NO·) is a well-known mediator of vascular tone. What is not so well recognized is that NO· exists in several different redox forms. There is considerable evidence that NO· and its one-electron reduction product, nitroxyl (HNO), have pharmacologically distinct actions that extend into the regulation of the vasculature. The aim of this study was to compare the vasorelaxation mechanisms of HNO and NO·, including an examination of the ability of these redox variants to hyperpolarize and repolarize vascular smooth muscle cells from rat mesenteric arteries. The HNO donor Angeli's salt (0.1 nM–10 μM) caused a concentration-dependent hyperpolarization of vessels at resting tone and a simultaneous, concentration-dependent vasorelaxation and repolarization of vessels precontracted and depolarized with methoxamine. Both vasorelaxation and repolarization responses to Angeli's salt were significantly attenuated by both the HNO scavenger l-cysteine (3 mM) and the voltage-dependent K+ (Kv) channel inhibitor 4-aminopyridine (4-AP; 1 mM) and virtually abolished by the soluble guanylate cyclase (sGC) inhibitor 1 H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ; 10 μM) or 30 mM K+. In contrast, NO· (0.01–1 μM) repolarized arteries to a lesser extent than HNO, and these responses were resistant to inhibition by ODQ (10 μM) and 4-AP (1 mM). Blockade of Kv channels (1 mM 4-AP) also significantly inhibited the repolarization response to YC-1 (0.1–10 μM), confirming a role for sGC/cGMP in the activation of Kv channels in this preparation. We conclude that HNO causes vasorelaxation via a cGMP-dependent activation of Kv channels and that there are different profiles of vasorelaxant activity for the redox siblings HNO and NO·.

Abstract MP31: Peripheral Vascular Dysfunction In A Model Of Small Vessel Disease Of The Brain (CADASIL) Involves Impaired Redox-sensitive Cyclic GMP/PKG Signaling

Hypertension ◽  
2020 ◽  
Vol 76 (Suppl_1) ◽  
Author(s):  
Karla B Neves ◽  
Hannah Morris ◽  
Rheure Alves-lopes ◽  
Augusto C Montezano ◽  
Rhian M Touyz
Keyword(s):  
Soluble Guanylate Cyclase ◽  
Small Vessel Disease ◽  
Vascular Dysfunction ◽  
Plasma Lipid ◽  
Fold Increase ◽  
Mesenteric Arteries ◽  
Small Vessel ◽  
Resistance Arteries ◽  
Vessel Disease ◽  
The Brain

CADASIL, a monogenic condition due to Notch3 mutations, is a very aggressive small vessel disease of the brain resulting in premature vascular dementia and stroke. Changes in cerebral vessels include vascular dysfunction and narrowing, and accumulation of granular osmiophilic material (GOM). It is not clear whether small peripheral arteries undergo similar damage. Therefore, our aim is to assess vascular dysfunction and associated mechanisms in mesenteric resistance arteries from CADASIL mice. Mesenteric arteries (MA) from male CADASIL-causing Notch3 mutation (TgNotch3 R169C ) and wildtype (TgNotch3 WT ) mice (6 months old) were investigated. GOM deposits in MA from CADASIL mice were identified by electron microscopy. mRNA expression of Notch3 (WT: 2.0±0.5 vs. 6.0±1.3) and its downstream target HeyL (WT: 1.1±0.4 vs. 2.9±0.6) was augmented in CADASIL mice (p<0.01), suggesting increased Notch3 activation. CADASIL mice exhibited endothelial-dependent (Emax 109.9±7.4 vs. 81.3±5.4) and -independent dysfunction (pD 2 7.8±0.1 vs. 6.8±0.3); effects associated with increased eNOS inhibition (p-Thr 495 ) (1.8-fold increase) and decreased cGMP levels (1.2±0.2 vs. 0.59±0.2) (p<0.05). Plasma lipid peroxidation (0.8±0.1 vs. 2.0±0.3; p<0.05) and vascular reactive oxygen species (ROS) production (7.2±1.9 vs. 75.4±35.0; p<0.05) were increased in TgNotch3 R169C mice; processes associated with upregulation of soluble guanylate cyclase (sGC) oxidation and decreased sGC activity. H 2 O 2 levels were decreased in TgNotch3 R169C mice (1.9±0.2 vs. 1.1±1.9; p<0.05), which was associated with reduced activation of protein kinase G (PKG). Observations in TgNotch3 R169C mice were recapitulated in human CADASIL, where ROS levels (0.8±0.1 vs. 4.1±2.7; p<0.05) and sGC oxidation were also increased. Our findings demonstrate that the vasculopathy associated with a CADASIL Notch3 gain-of-function mutation in peripheral small vessels involves reduction in eNOS activation and redox-sensitive processes leading to impaired sGC/cGMP signalling pathway. We identify a potential new therapeutic target in CADASIL, for which there are no disease-specific treatments.

Abstract 15995: Role of Kir Channels in Flow-Induced Vasodilatation

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Sang Joon Ahn ◽  
Jing-Tan Bian ◽  
Sarah Schwab ◽  
Mary Szczurek ◽  
Shane A Phillips ◽  
...  
Keyword(s):  
Vascular Tone ◽  
Significant Inhibition ◽  
Dominant Negative ◽  
Mesenteric Arteries ◽  
Resistance Arteries ◽  
Nitric Oxide Synthase Inhibitor ◽  
Kir Channels ◽  
No Release ◽  
Synthase Inhibitor

Introduction: Flow-induced vasodilation (FIV) is an important physiological stimulus for regulating vascular tone. A loss of endothelial-dependent FIV is an early indication of endothelial dysfunction. Earlier studies proposed that endothelial inwardly-rectifying K + channels (Kir) are putative flow sensors, but the role of Kir in the regulation of vascular tone is not known. Hypothesis: Kir channels play a key role in FIV. Methods: FIV was assessed in mouse mesenteric arteries isolated from wild type (WT) and Kir2.1 +/- heterozygous mice. Briefly, resistance arteries were isolated, cannulated and pressurized in an organ chamber with glass micropipettes. Preparations were visualized in real time and the inner diameter of the vessels was measured using acquired images. Kir channels in arteries isolated from WT mice were downregulated by a dominant-negative subunit of Kir2.1 or blocked by Ba 2+ . The role of Kir channels in flow-induced release of NO was tested by Diaminorhodamine-4M, NO specific fluorescence dye. Results: Our results show that FIV is significantly inhibited in mesenteric arteries isolated from Kir2.1 +/- mice that have reduced Kir2.1 expression as compared with WT mice (42%±3% relaxation in Kir2.1 +/- vs 94.06%±2.2% in WT mice, n=11, p<0.05). Moreover, blocking Kir channels with Ba 2+ or downregulating its activity with a dominant-negative subunit of Kir2.1 also resulted in significant inhibition of FIV in arteries isolated from WT mice (47%±3% relaxation in the presence of Ba 2+ , 43%±5% in arteries infected with dnKir2.1 vs 94.06%±2.2% in WT n=3, p<0.05). As expected, inhibiting NO release by LNAME, a nitric oxide synthase inhibitor, reduced FIV in WT arteries (39%±5%, n=4, p<0.05), but no effect was observed in arteries isolated from Kir2.1 +/- mice. Furthermore, flow-induced release of NO was significantly reduced (1.5-fold decreased, p<0.05). In contrast, inhibiting Ca 2+ -dependent K + channels (SK/IK) had an additive effect to Kir suppression suggesting that SK/IK and Kir channels regulate FIV by parallel pathways. In conclusion, our results indicate that Kir channels contribute significantly to FIV by regulating NO release.

scholarly journals Mechanism of the Enhanced Vasoconstrictor Responses to Endothelin-1 in Canine Cerebral Arteries

1991 ◽  
Vol 11 (3) ◽  
pp. 371-379 ◽  
Author(s):  
Chiharu Tanoi ◽  
Yoshio Suzuki ◽  
Masato Shibuya ◽  
Kenichiro Sugita ◽  
Kaoru Masuzawa ◽  
...  
Keyword(s):  
Basilar Artery ◽  
Resting State ◽  
Mesenteric Artery ◽  
Cerebral Arteries ◽  
Mesenteric Arteries ◽  
Free Solution ◽  
Contractile Responses ◽  
Endothelin 1 ◽  
Voltage Dependent ◽  
Small Contraction

Vasoconstrictor effects of endothelin-1 (ET) were investigated in endothelium-denuded strips of cerebral (basilar and posterior cerebral) and mesenteric arteries of the dog. ET produced a concentration-dependent contraction in these arteries. Contractile responses to lower concentrations (below 3 × 10−10 M) of ET were significantly greater in the cerebral arteries than in the mesenteric artery. Inhibition by nifedipine of the contractile responses to ET was greater in the basilar artery than in the mesenteric artery. After the inhibition by 10−7 M nifedipine, the remaining responses to ET were similar in the two arteries. Cerebral arteries, but not the mesenteric artery, relaxed significantly from the resting level when placed in a Ca2+ -free solution containing 0.1 m M EGTA (0-Ca solution). Readdition of Ca2+ to the cerebral arteries placed in the 0-Ca solution caused a biphasic contraction that was sensitive to nifedipine. When 10−9 M ET was introduced before the Ca2+-induced contraction, this peptide produced only a very small contraction, but enhanced the Ca2+-induced contraction. The extent of the enhancement induced by ET was much greater in the cerebral arteries than in the mesenteric artery. These results indicate that the enhanced responses to ET in the cerebral arteries were dependent to a large extent on Ca2+ influx through voltage-dependent Ca2+ channels (VDCs). It is likely that the VDCs in these arteries are more activated in the resting state than those in the mesenteric artery.

scholarly journals Redox and Antioxidant Modulation of Circadian Rhythms: Effects of Nitroxyl, N-Acetylcysteine and Glutathione

Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2514
Author(s):  
Santiago Andrés Plano ◽  
Fernando Martín Baidanoff ◽  
Laura Lucía Trebucq ◽  
Sebastián Ángel Suarez ◽  
Fabio Doctorovich ◽  
...  
Keyword(s):  
Soluble Guanylate Cyclase ◽  
Phase Locking ◽  
Cyclic Guanosine Monophosphate ◽  
Guanosine Monophosphate ◽  
Circadian Phase ◽  
Subjective Night ◽  
Circadian Time ◽  
Electron Reduction ◽  
Locomotor Rhythms ◽  
The One

The circadian clock at the hypothalamic suprachiasmatic nucleus (SCN) entrains output rhythms to 24-h light cycles. To entrain by phase-advances, light signaling at the end of subjective night (circadian time 18, CT18) requires free radical nitric oxide (NO•) binding to soluble guanylate cyclase (sGC) heme group, activating the cyclic guanosine monophosphate (cGMP)-dependent protein kinase (PKG). Phase-delays at CT14 seem to be independent of NO•, whose redox-related species were yet to be investigated. Here, the one-electron reduction of NO• nitroxyl was pharmacologically delivered by Angeli’s salt (AS) donor to assess its modulation on phase-resetting of locomotor rhythms in hamsters. Intracerebroventricular AS generated nitroxyl at the SCN, promoting phase-delays at CT14, but potentiated light-induced phase-advances at CT18. Glutathione/glutathione disulfide (GSH/GSSG) couple measured in SCN homogenates showed higher values at CT14 (i.e., more reduced) than at CT18 (oxidized). In addition, administration of antioxidants N-acetylcysteine (NAC) and GSH induced delays per se at CT14 but did not affect light-induced advances at CT18. Thus, the relative of NO• nitroxyl generates phase-delays in a reductive SCN environment, while an oxidative favors photic-advances. These data suggest that circadian phase-locking mechanisms should include redox SCN environment, generating relatives of NO•, as well as coupling with the molecular oscillator.

scholarly journals Pregnancy Enhances the Angiotensin (Ang)-(1–7) Vasodilator Response in Mesenteric Arteries and Increases the Renal Concentration and Urinary Excretion of Ang-(1–7)

Endocrinology ◽  
2003 ◽  
Vol 144 (8) ◽  
pp. 3338-3343 ◽  
Author(s):  
Liomar A. A. Neves ◽  
Aleck F. Williams ◽  
David B. Averill ◽  
Carlos M. Ferrario ◽  
Michael P. Walkup ◽  
...  
Keyword(s):  
Urinary Excretion ◽  
Excretion Rate ◽  
Virgin Female ◽  
Cardiovascular Regulation ◽  
Mesenteric Arteries ◽  
Female Rats ◽  
Resistance Arteries ◽  
Urinary Excretion Rate ◽  
Response Curves ◽  
Mesenteric Vessels

Abstract The vasoactive effect of angiotensin (Ang)-(1–7) in mesenteric resistance arteries together with its plasma and kidney concentration and urinary excretion was assessed in pregnant and virgin rats. Mesenteric arteries (230–290 μm) were mounted in a pressurized myograph system and Ang-(1–7) concentration-dependent response curves (10−10–10−5m) were determined in arteries preconstricted with endothelin-1 (10−7m). The Ang-(1–7) response was investigated in vessels with and without pretreatment with the Ang-(1–7) antagonist [d-[Ala7]-Ang-(1–7)] (10−7m). Ang-(1–7) caused a significantly enhanced, concentration-dependent dilation of mesenteric vessels (EC50 = 2.7 nm) from pregnant compared with virgin female rats. d-[Ala7]-Ang-(1–7) eliminated the vasodilator effect of Ang-(1–7). There was no significant change in plasma concentration of Ang-(1–7) in pregnant animals. On the other hand, 24 h urinary excretion and kidney concentration of Ang-(1–7) were significantly higher in pregnant animals. The increased mesenteric dilation to Ang-(1–7) with enhanced kidney concentration and 24 h urinary excretion rate of Ang-(1–7) suggests an important role for this peptide in cardiovascular regulation during pregnancy.

Tonic regulation of vascular tone by nitric oxide and chloride ions in rat isolated small coronary arteries

2000 ◽  
Vol 279 (6) ◽  
pp. H2604-H2611 ◽  
Author(s):  
Jonathan E. Graves ◽  
Iain A. Greenwood ◽  
William A. Large
Keyword(s):  
Nitric Oxide ◽  
Coronary Arteries ◽  
Vascular Tone ◽  
Physiological Saline ◽  
Chloride Ions ◽  
Bathing Solution ◽  
Contractile Mechanism ◽  
Mechanical Removal ◽  
Voltage Dependent ◽  
Physiological Saline Solution

We have investigated the involvement of Cl− in regulating vascular tone in rat isolated coronary arteries mounted on a small vessel myograph. Mechanical removal of the endothelium or inhibition of nitric oxide (NO) synthase with N ω-nitro-l-arginine methyl ester (l-NAME, 10−4 M) led to contraction of rat coronary arteries, and these contractions were sensitive to nicardipine (10−6 M). This suggests that release of NO tonically inhibits a contractile mechanism that involves voltage-dependent Ca2+ channels. In arteries contracted withl-NAME, switching the bathing solution to physiological saline solution with a reduced Cl− concentration potentiated the contraction. DIDS (5 × 10−6–3 × 10−4 M) caused relaxation of l-NAME-induced tension (IC50 = 55 ± 10 μM), providing evidence for a role of Cl−. SITS (10−5–5 × 10−4 M) did not affectl-NAME-induced tension, suggesting that DIDS is not acting by inhibition of anion exchange. Mechanical removal of the endothelium led to contraction of arteries, which was sensitive to DIDS (IC50 = 50 ± 8 μM) and was not affected by SITS. This study suggests that, in rat coronary arteries, NO tonically suppresses a contractile mechanism that involves a Cl−conductance.

Modulation of arterial Na+-K+-ATPase-induced [Ca2+]i reduction and relaxation by norepinephrine, ET-1, and PMA

1999 ◽  
Vol 276 (2) ◽  
pp. H651-H657 ◽  
Author(s):  
Francisco Pérez-Vizcaíno ◽  
Angel Cogolludo ◽  
Juan Tamargo
Keyword(s):  
Enzyme Activity ◽  
Smooth Muscle ◽  
Membrane Potential ◽  
Atpase Activity ◽  
Vascular Tone ◽  
Smooth Muscle Contraction ◽  
Mesenteric Arteries ◽  
Free Solution ◽  
Kinase C ◽  
Protein Kinase C Inhibitor

Na+-K+-ATPase plays a major role in regulating membrane potential and vascular tone. We analyzed the modulation by norepinephrine (NE), endothelin-1 (ET-1), and phorbol 12-myristate 13-acetate (PMA) of Na+-K+-ATPase-induced cytoplasmic free Ca2+concentration ([Ca2+]i) reduction and relaxation in isolated endothelium-denuded piglet mesenteric arteries. KCl (0.2–8.8 mM)-induced [Ca2+]ireduction and relaxation in arteries incubated in K+-free solution were used as functional indicators of Na+-K+-ATPase activity. KCl-induced relaxations after exposure to K+-free solution were associated with a reduction in [Ca2+]i, as measured by fura 2 fluorescence. However, KCl reduced [Ca2+]ibelow resting values, whereas force was reduced to near resting values. NE, ET-1, and PMA inhibited the relaxant effects of KCl, and this effect was attenuated by the protein kinase C inhibitor staurosporine but not by the phospholipase A2inhibitor quinacrine. However, ET-1 and PMA potentiated the [Ca2+]i-reducing effect of KCl. In conclusion, ET-1, PMA, and NE are functional inhibitors of Na+-K+-ATPase activity in endothelium-denuded piglet mesenteric arteries, even when the direct effect on the enzyme activity may be stimulatory rather than inhibitory. This can be explained because ET-1, PMA, and NE induce Ca2+ sensitization for smooth muscle contraction, and therefore relaxations do not parallel the reductions in [Ca2+]iafter the activation of Na+-K+-ATPase.

Simulated microgravity alters rat mesenteric artery vasoconstrictor dynamics through an intracellular Ca2+ release mechanism

2008 ◽  
Vol 294 (5) ◽  
pp. R1577-R1585 ◽  
Author(s):  
Patrick N. Colleran ◽  
Bradley J. Behnke ◽  
M. Keith Wilkerson ◽  
Anthony J. Donato ◽  
Michael D. Delp
Keyword(s):  
Temporal Dynamics ◽  
Orthostatic Intolerance ◽  
Mesenteric Arteries ◽  
Release Mechanism ◽  
Resistance Arteries ◽  
Receptor Mrna ◽  
Cardiovascular Deconditioning ◽  
Rat Mesenteric Artery ◽  
Mrna And Protein Expression

Previous work has shown that orthostatic hypotension associated with cardiovascular deconditioning results from inadequate peripheral vasoconstriction. We used the hindlimb-unloaded (HU) rat in this study as a model to induce cardiovascular deconditioning. The purpose of this study was to test the hypothesis that 14 days of HU diminishes vasoconstrictor responsiveness of mesenteric resistance arteries. Mesenteric resistance arteries from control ( n = 43) and HU ( n = 44) rats were isolated, cannulated, and pressurized to 108 cm H2O for in vitro experimentation. Myogenic (intralumenal pressure ranging from 30 to 180 cm H2O), KCl (2–100 mM), norepinephrine (NE, 10−9–10−4 M) and caffeine (1–20 mM) induced vasoconstriction, as well as the temporal dynamics of vasoconstriction to NE, were determined. The active myogenic and passive pressure responses were unaltered by HU when pressures remained within physiological range. However, vasoconstrictor responses to KCl, NE, and caffeine were diminished by HU, as well as the rate of constriction to NE (C, 14.8 ± 3.6 μm/s vs. HU 7.6 ± 1.8 μm/s). Expression of sarcoplasmic reticulum Ca2+ATPase 2 and ryanodine 3 receptor mRNA was unaffected by HU, while ryanodine 2 receptor mRNA and protein expression were diminished in mesenteric arteries from HU rats. These data suggest that HU-induced and microgravity-associated orthostatic intolerance may be due, in part, to an attenuated vasoconstrictor responsiveness of mesenteric resistance arteries resulting from a diminished ryanodine 2 receptor Ca2+ release mechanism.

Abstract P217: Nox Compartmentalization, Protein Oxidation and ER Stress in Vascular Smooth Muscle Cells in Hypertension

Hypertension ◽  
2017 ◽  
Vol 70 (suppl_1) ◽  
Author(s):  
Livia L Camargo ◽  
Augusto C Montezano ◽  
Adam Harvey ◽  
Sofia Tsiropoulou ◽  
Katie Hood ◽  
...  
Keyword(s):  
Er Stress ◽  
Protein Oxidation ◽  
Vascular Function ◽  
Vascular Reactivity ◽  
Stress Proteins ◽  
Vascular Dysfunction ◽  
Mesenteric Arteries ◽  
Resistance Arteries ◽  
Post Translational Modification ◽  
Wistar Kyoto

In hypertension, activation of NADPH oxidases (Noxs) is associated with oxidative stress and vascular dysfunction. The exact role of each isoform in hypertension-associated vascular injury is still unclear. We investigated the compartmentalization of Noxs in VSMC from resistance arteries of Wistar Kyoto (WKY) and spontaneously hypertensive rats (SHR). Expression of Nox1 and Nox4 was increased in SHR cells (96.6±28.7% and 48.2±21.2% vs WKY, p<0.05), as well as basal ROS levels measured by chemiluminescence (110.2±26.4% vs WKY, p<0.05) and amplex red (105.2±33.2% vs WKY, p<0.05). Phosphorylation of unfolded protein response activators, PERK and IRE1α, and expression of ER chaperone BiP were elevated in SHR cells (p<0.05 vs WKY), indicating activation of ER stress response. Immunoblotting after organelle fractionation demonstrated that Noxs are expressed in an organelle-specific manner, with Nox1, 2 and 4 present in plasma membrane, ER and nucleus, but not in mitochondria. In SHR cells, NoxA1ds (Nox1 inhibitor, 10μM) and GKT136901 (Nox1/4 inhibitor, 10μM) decreased AngII-induced ROS levels (p<0.001 vs Ctl). Additionally, mito-tempol (mitochondrial-targeted antioxidant, 50nM) and 4-PBA (ER stress inhibitor, 1mM) decreased basal ROS levels in SHR cells (p<0.05 vs Ctl). Furthermore, oxidation of the antioxidant enzymes Peroxiredoxins (Prx) was increased in SHRSP compared to WKY (2.51±0.14 vs 0.56±0.07, p<0.001). One-dimensional isoelectric focusing revealed that cytosolic Prx2 and mitochondrial Prx3 were more oxidized in SHRSP than WKY cells. Using a biotin-tagged dimedone-based probe (DCP-Bio) we identified oxidation of ER stress proteins BiP and IRE1. To investigate the effect of protein oxidation in vascular function, vascular reactivity was evaluated in isolated mesenteric arteries. Inhibition of general oxidation (DTT 1mM; Emax: 111.7±33.1) and peroxiredoxin (Conoidin A 10nM; Emax: 116.0±7.3) reduces vascular contraction in response to noradrenalin in WKY rats (Emax: 166.6±30.2; p<0.05). These findings suggest an important role for Nox1/4 in redox-dependent organelle dysfunction and post-translational modification of proteins, processes that may play an important role in vascular dysfunction in hypertension.

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