The permissive role of endothelial NO in CO-induced cerebrovascular dilation

2004 ◽  
Vol 287 (4) ◽  
pp. H1459-H1465 ◽  
Author(s):  
Ebrahim Barkoudah ◽  
Jonathan H. Jaggar ◽  
Charles W. Leffler
Keyword(s):  
Guanylyl Cyclase ◽  
Constant Concentration ◽  
No Donor ◽  
Tetraethylammonium Chloride ◽  
Dimanganese Decacarbonyl ◽  
Cgmp Analog ◽  
Pial Arterioles ◽  
Permissive Role ◽  
Intravascular Pressure

Carbon monoxide (CO) and nitric oxide (NO) are important paracrine messengers in the newborn cerebrovasculature that may act as comessengers. Here, we investigated the role of NO in CO-mediated dilations in the newborn cerebrovasculature. Arteriolar branches of the middle cerebral artery (100–200 μm) were isolated from 3- to 7-day-old piglets and cannulated at each end in a superfusion chamber, and intravascular pressure was elevated to 30 mmHg, which resulted in the development of myogenic tone. Endothelium removal abolished dilations of pressurized pial arterioles to bradykinin and to the CO-releasing molecule Mn2(CO)10 [dimanganese decacarbonyl (DMDC)] but not dilations to isoproterenol. With endothelium intact, Nω-nitro-l-arginine (l-NNA), 1 H-[1,2,4]oxadiazolo-[4,3-a]quinoxalin-1-one (ODQ), or tetraethylammonium chloride (TEA+), inhibitors of NO synthase (NOS), guanylyl cyclase, and large-conductance Ca2+-activated K+ (KCa) channels, respectively, also blocked dilation induced by DMDC. After inhibition of NOS, a constant concentration of sodium nitroprusside (SNP), a NO donor that only dilated the vessel 6%, returned dilation to DMDC. The stable cGMP analog 8-bromo-cGMP also restored dilation to DMDC in endothelium-intact, l-NNA-treated, or endothelium-denuded arterioles, and this effect was blocked by TEA+. Similarly, in the continued presence of ODQ, 8-bromo-cGMP restored DMDC-induced dilations. These findings suggest that endothelium-derived NO stimulates guanylyl cyclase in vascular smooth muscle cells and, thereby, permits CO to cause dilation by activating KCa channels. Such a requirement for NO could explain the endothelium dependency of CO-induced dilation in piglet pial arterioles.

Role of cGMP in carbon monoxide-induced cerebral vasodilation in piglets

2004 ◽  
Vol 286 (1) ◽  
pp. H304-H309 ◽  
Author(s):  
Padmaja Koneru ◽  
Charles W. Leffler
Keyword(s):  
Nitric Oxide ◽  
Cerebrospinal Fluid ◽  
Soluble Guanylyl Cyclase ◽  
Cellular Level ◽  
No Synthase ◽  
Dimanganese Decacarbonyl ◽  
Pial Arterioles ◽  
Cerebral Vasodilation ◽  
Permissive Role

The hypothesis was addressed that CO-induced cerebral vasodilation requires a permissive cGMP signal that can be produced by nitric oxide (NO). Anesthetized piglets were implanted with cranial windows for measurement of pial arteriolar responses to stimuli. Pial arterioles dilated in response to isoproterenol (Iso), sodium nitroprusside (SNP), and CO or the CO-releasing molecule Mn2(CO)10 [dimanganese decacarbonyl (DMDC)]. 1 H-[1,2,4]oxadiazolo[4,3- a]quinoxalin-1-one (ODQ), a soluble guanylyl cyclase inhibitor, decreased cerebrospinal fluid (CSF) cGMP and selectively inhibited dilations to SNP and DMDC without affecting the dilation to Iso. However, DMDC did not cause an increase in cortical periarachnoid CSF cGMP concentration. cGMP clamp with a threshold dilator level of 8-bromo-cGMP (10–4 M) and ODQ restored the dilation to DMDC that had been blocked by ODQ alone. Under these conditions, cGMP was present but could not increase. Inhibition of the pial arteriolar dilation to glutamate by N-nitro-l-arginine, which blocks NO synthase, was similar to that by heme oxygenase inhibitors, which block endogenous CO production. The dilation to glutamate, similar to dilation to DMDC, was partially restored by 8-bromo-cGMP and completely restored by SNP (5 × 10–7 M). These data suggest that the permissive role of NO in CO- and glutamate-induced vasodilation involves maintaining the minimum necessary cellular level of cGMP to allow CO to cause dilation independently of increasing cGMP.

scholarly journals Effect of time and vascular pressure on permeability and cyclic nucleotides in ischemic lungs

2000 ◽  
Vol 279 (5) ◽  
pp. H2077-H2084 ◽  
Author(s):  
David B. Pearse ◽  
Patrice M. Becker
Keyword(s):  
Nitric Oxide ◽  
High Pressure ◽  
Reflection Coefficient ◽  
Cyclic Nucleotides ◽  
Fluid Flux ◽  
No Donor ◽  
Independent Mechanism ◽  
Dependent Mechanism ◽  
Intravascular Pressure

We previously found that increased intravascular pressure decreased ischemic lung injury by a nitric oxide (NO)-dependent mechanism (Becker PM, Buchanan W, and Sylvester JT. J Appl Physiol 84: 803–808, 1998). To determine the role of cyclic nucleotides in this response, we measured the reflection coefficient for albumin (ςalb), fluid flux ( J˙), cGMP, and cAMP in ferret lungs subjected to either 45 min (“short”; n = 7) or 180 min (“long”) of ventilated ischemia. Long ischemic lungs had “low” (1–2 mmHg, n = 8) or “high” (7–8 mmHg, n = 6) vascular pressure. Other long low lungs were treated with the NO donor ( Z)-1-[ N-(3-ammoniopropyl)- N-( n-propyl)amino]diazen-1-ium-1,2-diolate (PAPA-NONOate; 5 × 10−4 M, n = 6) or 8-bromo-cGMP (5 × 10−4 M, n = 6). Compared with short ischemia, long low ischemia decreased ςalb (0.23 ± 0.04 vs. 0.73 ± 0.08; P < 0.05) and increased J˙ (1.93 ± 0.26 vs. 0.58 ± 0.22 ml · min−1 · 100 g−1; P < 0.05). High pressure prevented these changes. Lung cGMP decreased by 66% in long compared with short ischemia. Lung cAMP did not change. PAPA-NONOate and 8-bromo-cGMP increased lung cGMP, but only 8-bromo-cGMP decreased permeability. These results suggest that ischemic vascular injury was, in part, mediated by a decrease in cGMP. Increased vascular pressure prevented injury by a cGMP-independent mechanism that could not be mimicked by administration of exogenous NO.

Involvement of guanylyl cyclase and cGMP in the regulation of Mrp2-mediated transport in the proximal tubule

2004 ◽  
Vol 287 (1) ◽  
pp. F33-F38 ◽  
Author(s):  
Sylvia Notenboom ◽  
David S. Miller ◽  
P. Smits ◽  
Frans G. M. Russel ◽  
Rosalinde Masereeuw
Keyword(s):  
Guanylyl Cyclase ◽  
Organic Anion ◽  
No Donor ◽  
Quantitative Image ◽  
Cgmp Signaling ◽  
Cgmp Analog ◽  
A Cell ◽  
Protein Isoform ◽  
Nos Inhibitor ◽  
Oxide Synthase

In killifish renal proximal tubules, endothelin-1 (ET-1), acting through a basolateral ETB receptor, nitric oxide synthase (NOS), and PKC, decreases cell-to-lumen organic anion transport mediated by the multidrug resistance protein isoform 2 (Mrp2). In the present study, we examined the roles of guanylyl cyclase and cGMP in ET signaling to Mrp2. Using confocal microscopy and quantitative image analysis to measure Mrp2-mediated transport of the fluorescent drug fluorescein methotrexate (FL-MTX), we found that oxadiazole quinoxalin (ODQ), an inhibitor of NO-sensitive guanylyl cyclase, blocked ET-1 signaling. ODQ was also effective when signaling was initiated by nephrotoxicants (gentamicin, amikacin, diatrizoate, HgCl2, and CdCl2), which appear to stimulate ET release from the tubules themselves. ODQ blocked the effects of the NO donor sodium nitroprusside but not of the phorbol ester that activates PKC. Exposing tubules to 8-bromo-cGMP (8-BrcGMP), a cell-permeable cGMP analog, decreased luminal FL-MTX accumulation. This effect was abolished by bisindoylmaleimide (BIM), a PKC inhibitor, but not by NG-methyl-l-arginine, a NOS inhibitor. Together, these data indicate that ET regulation of Mrp2 involves activation of guanylyl cyclase and generation of cGMP. Signaling by cGMP follows NO release and precedes PKC activation.

scholarly journals Inhibition of ovarian steroidogenesis by cyclic GMP in a fly

2003 ◽  
Vol 177 (1) ◽  
pp. 35-44 ◽  
Author(s):  
G Maniere ◽  
E Vanhems ◽  
F Gautron ◽  
JP Delbecque
Keyword(s):  
Close Correlation ◽  
Negative Control ◽  
Phormia Regina ◽  
No Donor ◽  
Ovarian Steroidogenesis ◽  
Cgmp Analog ◽  
Ecdysteroid Biosynthesis ◽  
Negative Effect ◽  
First Time

Previous investigations in the female blowfly Phormia regina have shown that 3-isobutyl-1-methylxanthine (IBMX), a broad spectrum inhibitor of phosphodiesterases (PDEs), fails to mimic the steroidogenic effects of cAMP on ovaries, although it efficiently increases the concentrations of this second messenger. In this study, experiments carried out to clear up this contradiction demonstrated that IBMX, besides its effect on cAMP, also increased cGMP concentrations in blowfly ovary and that these two cyclic nucleotides controlled ovarian steroidogenesis antagonistically. In particular, a selective inhibitor of cGMP-specific PDEs, unlike IBMX, had a very strong negative effect on ovarian steroidogenesis. Moreover, a cGMP analog was able to inhibit steroid biosynthesis in previtellogenic and vitellogenic ovaries, thus affecting basal and acute steroidogenesis respectively. Our observations also demonstrated that cGMP was always present in blowfly ovary, reaching its maximal levels at the end of vitellogenesis, in close correlation with the physiological decrease in ovarian steroidogenesis. Experiments using an inhibitor of protein kinase G clearly indicated that the effects of cGMP were mediated by this enzyme. On the contrary, these effects did not seem to involve cGMP-regulated PDEs or ion channels. Our results also indicated that ovarian cGMP concentrations were not controlled by brain factors, suggesting a probable involvement of paracrine/autocrine factors. Nitric oxide (NO) appeared to be a good candidate for such a control, because an NO donor was able to stimulate ovarian cGMP concentrations and to drastically decrease ovarian ecdysteroid biosynthesis in blowflies. These data thus demonstrate, for the first time in invertebrates, a potent role of cGMP in the negative control of ovarian steroidogenesis and suggest a possible co-regulation with NO.

Biphasic Roles for the Soluble Guanylyl Cyclase (sGC) In Platelet Activation In Mice

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 486-486
Author(s):  
Guoying Zhang ◽  
Binggang Xiang ◽  
Radek C. Skoda ◽  
Susan S. Smyth ◽  
Xiaoping Du ◽  
...  
Keyword(s):  
Platelet Activation ◽  
Guanylyl Cyclase ◽  
Conflicts Of Interest ◽  
Soluble Guanylyl Cyclase ◽  
Wild Type ◽  
No Donor ◽  
Cgmp Production ◽  
Deficient Mice

Abstract Abstract 486 The role of intracellular secondary messenger cGMP in platelet activation has been controversial, with both stimulatory and inhibitory roles reported. The platelet cGMP is believed to be predominantly synthesized by soluble guanylyl cyclase (sGC), which is activated by nitric oxide (NO). To specifically determine the role of sGC-dependent cGMP synthesis in platelet function and in vivo thrombosis and hemostasis, we produced mice harboring a “floxed” sGC beta1 allele. In the “floxed” sGC beta1 mice (sGC beta1fl/fl), the exons 7 and 8 of sGC beta1 gene and an inserted Neo cassette were flanked with three LoxP sites. Platelet-specific deletion of sGC beta1fl/fl allele was accomplished through breeding of the sGC beta1fl/fl mice with pf4-Cre recombinase transgenic mice. Immunoblotting showed the complete absence of this protein in sGC beta1fl/fl/Cre platelets. Mice lacking sGC beta1 in platelets appeared to develop normally and had normal blood counts, including platelets. Blood pressure of platelet-specific sGC deficient mice was comparable to that of wild-type littermates. Inactivating the sGC beta1 gene in platelets abolished cGMP production induced by either NO donors or platelet agonists that are known to activate endogenous NO synthesis, confirming that both the platelet agonist-induced and NO donor-induced platelet cGMP production are predominantly mediated by sGC. Platelets lacking sGC exhibit a marked defect in aggregation and secretion in response to low doses of platelet agonists, collagen and thrombin. Importantly, tail-bleeding times were significantly prolonged in the platelet-specific sGC deficient mice compared with the wild-type littermates. In a FeCl3-induced carotid artery thrombosis model, time to occlusive thrombosis was prolonged in the platelet-specific sGC deficient mice, compared to wild type littermates. Thus, the agonist-stimulated sGC activation is important in promoting platelet granule secretion and aggregation. On the other hand, NO donor SNP-induced inhibition of platelet activation was abolished in sGC-deficient platelets. However, at high concentrations (>100μM), SNP inhibited platelet activation in both wild type and sGC deficient mice, indicating that both cGMP-dependent and -independent mechanisms are involved in NO donor-induced inhibition of platelet activation. Together, our data demonstrate that sGC contributes to both agonist-induced platelet activation and NO donor-induced platelet inhibition. Disclosures: No relevant conflicts of interest to declare.

Nitric oxide relaxes human myometrium by a cGMP-independent mechanism

1998 ◽  
Vol 275 (6) ◽  
pp. C1668-C1673 ◽  
Author(s):  
Karri K. Bradley ◽  
Iain L. O. Buxton ◽  
James E. Barber ◽  
Terrence McGaw ◽  
Michael E. Bradley
Keyword(s):  
Nitric Oxide ◽  
Guanylyl Cyclase ◽  
Contractile Activity ◽  
Human Myometrium ◽  
Intracellular Camp ◽  
No Donor ◽  
Calcium Dependent ◽  
Spontaneous Contractions ◽  
Ly 83583

The role of intracellular guanosine 3′,5′-cyclic monophosphate concentration ([cGMP]i) in nitric oxide (NO)-mediated relaxations in the uterus has become controversial. We found the NO donor S-nitroso-l-cysteine (CysNO) to potently (IC50 = 30 nM) inhibit spontaneous contractions in the nonpregnant human myometrium. CysNO treatment increased [cGMP]i significantly ( P < 0.001), and this increase was blocked by the guanylyl cyclase inhibitors methylene blue (10 μM) or LY-83583 (1 μM); however, pretreatment with these guanylyl cyclase inhibitors failed to block CysNO-mediated relaxations. Intracellular cAMP concentrations were not altered by treatment of tissues with 10 μM CysNO. Incubation with the cGMP analogs 8-bromo-cGMP or β-phenyl-1, N 2-etheno-cGMP did not significantly affect spontaneous contractility. Pretreatment of tissues with charybdotoxin [a calcium-dependent potassium channel (BK) blocker] completely reversed CysNO-induced relaxations. We conclude that NO is a potent inhibitor of spontaneous contractile activity in the nonpregnant human uterus and that, although guanylyl cyclase and BK activities are increased by NO, increases in [cGMP]i are not required for NO-induced relaxations in this tissue.

scholarly journals Soluble guanylyl cyclase is a critical regulator of migraine-associated pain

Cephalalgia ◽  
2017 ◽  
Vol 38 (8) ◽  
pp. 1471-1484 ◽  
Author(s):  
Manel Ben Aissa ◽  
Alycia F Tipton ◽  
Zachariah Bertels ◽  
Ronak Gandhi ◽  
Laura S Moye ◽  
...  
Keyword(s):  
Chronic Migraine ◽  
Guanylyl Cyclase ◽  
Nitrosative Stress ◽  
Soluble Guanylyl Cyclase ◽  
The Body ◽  
Dependent Manner ◽  
No Donor ◽  
Calcitonin Gene ◽  
Dose Dependent

Background Nitric oxide (NO) has been heavily implicated in migraine. Nitroglycerin is a prototypic NO-donor, and triggers migraine in humans. However, nitroglycerin also induces oxidative/nitrosative stress and is a source of peroxynitrite – factors previously linked with migraine etiology. Soluble guanylyl cyclase (sGC) is the high affinity NO receptor in the body, and the aim of this study was to identify the precise role of sGC in acute and chronic migraine. Methods We developed a novel brain-bioavailable sGC stimulator (VL-102), and tested its hyperalgesic properties in mice. We also determined the effect of VL-102 on c-fos and calcitonin gene related peptide (CGRP) immunoreactivity within the trigeminovascular complex. In addition, we also tested the known sGC inhibitor, ODQ, within the chronic nitroglycerin migraine model. Results VL-102-evoked acute and chronic mechanical cephalic and hind-paw allodynia in a dose-dependent manner, which was blocked by the migraine medications sumatriptan, propranolol, and topiramate. In addition, VL-102 also increased c-fos and CGRP expressing cells within the trigeminovascular complex. Importantly, ODQ completely inhibited acute and chronic hyperalgesia induced by nitroglycerin. ODQ also blocked hyperalgesia already established by chronic nitroglycerin, implicating this pathway in migraine chronicity. Conclusions These results indicate that nitroglycerin causes migraine-related pain through stimulation of the sGC pathway, and that super-activation of this receptor may be an important component for the maintenance of chronic migraine. This work opens the possibility for negative sGC modulators as novel migraine therapies.

scholarly journals Biphasic roles for soluble guanylyl cyclase (sGC) in platelet activation

Blood ◽  
2011 ◽  
Vol 118 (13) ◽  
pp. 3670-3679 ◽  
Author(s):  
Guoying Zhang ◽  
Binggang Xiang ◽  
Anping Dong ◽  
Radek C. Skoda ◽  
Alan Daugherty ◽  
...  
Keyword(s):  
Platelet Activation ◽  
Guanylyl Cyclase ◽  
Soluble Guanylyl Cyclase ◽  
Whole Body ◽  
No Donor ◽  
No Donors ◽  
Deficient Mice

AbstractNitric oxide (NO) stimulates cGMP synthesis by activating its intracellular receptor, soluble guanylyl cyclase (sGC). It is a currently prevailing concept that No and cGMP inhibits platelet function. However, the data supporting the inhibitory role of NO/sGC/cGMP in platelets have been obtained either in vitro or using whole body gene deletion that affects vessel wall function. Here we have generated mice with sGC gene deleted only in megakaryocytes and platelets. Using the megakaryocyte- and platelet-specific sGC-deficient mice, we identify a stimulatory role of sGC in platelet activation and in thrombosis in vivo. Deletion of sGC in platelets abolished cGMP production induced by either NO donors or platelet agonists, caused a marked defect in aggregation and attenuated secretion in response to low doses of collagen or thrombin. Importantly, megakaryocyte- and platelet-specific sGC deficient mice showed prolonged tail-bleeding times and impaired FeCl3-induced carotid artery thrombosis in vivo. Interestingly, the inhibitory effect of the NO donor SNP on platelet activation was sGC-dependent only at micromolar concentrations, but sGC-independent at millimolar concentrations. Together, our data demonstrate important roles of sGC in stimulating platelet activation and in vivo thrombosis and hemostasis, and sGC-dependent and -independent inhibition of platelets by NO donors.

Permissive role of NO in alpha 2-adrenoceptor-mediated dilations in rat cerebral arteries

1995 ◽  
Vol 269 (3) ◽  
pp. H1171-H1174 ◽  
Author(s):  
R. M. Bryan ◽  
M. L. Steenberg ◽  
M. Y. Eichler ◽  
T. D. Johnson ◽  
M. W. Swafford ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Cerebral Arteries ◽  
No Donor ◽  
Cyclic Monophosphate ◽  
Adrenoceptor Agonist ◽  
Middle Cerebral Arteries ◽  
Basal Release ◽  
Oxide Synthase ◽  
Permissive Role

Dilations produced with UK-14304, a selective alpha 2-adrenoceptor agonist, in rat middle cerebral arteries (MCAs) were blocked after removal of the endothelium or inhibition of nitric oxide synthase (NOS). After endothelium removal or inhibition of NOS, the addition of subthreshold doses of an exogenous nitric oxide (NO) donor, S-nitroso-N-acetylpenicillamine, restored the dilations produced by UK-14304. In a similar manner the guanosine 3',5'-cyclic monophosphate (cGMP) analogues 8-bromoguanosine 3',5'-cyclic monophosphate and N2,2'-O-dibutyrylguanosine 3',5'-cyclic monophosphate restored the dilations of MCAs after endothelial removal. Because NO cannot be synthesized and released in MCAs after inhibition of NOS, it cannot be directly responsible for the dilation. The basal release of NO from the endothelium acts permissively in the vasodilation by maintaining adequate levels of cGMP. Removal of this basal release of NO by removal of endothelium or inhibition of NOS abolishes the alpha 2-adrenoceptor-mediated dilation.

scholarly journals Downregulation of Soluble Guanylate Cyclase and Protein Kinase G With Upregulated ROCK2 in the Pulmonary Artery Leads to Thromboxane A2 Sensitization in Monocrotaline-Induced Pulmonary Hypertensive Rats

2021 ◽  
Vol 12 ◽  
Author(s):  
Suhan Cho ◽  
Hyun Namgoong ◽  
Hae Jin Kim ◽  
Rany Vorn ◽  
Hae Young Yoo ◽  
...  
Keyword(s):  
Pulmonary Artery ◽  
Guanylate Cyclase ◽  
Soluble Guanylate Cyclase ◽  
Thromboxane A2 ◽  
Immunoblot Analysis ◽  
No Donor ◽  
Cgmp Signaling ◽  
Cgmp Analog ◽  
Pulmonary Arterial

Thromboxane A2 (TXA2) promotes various physiological responses including pulmonary artery (PA) contraction, and pathophysiological implications have been suggested in cardiovascular diseases including pulmonary hypertension. Here, we investigated the role of TXA2 receptor (TP)-mediated signaling in the pathophysiology of pulmonary arterial hypertension (PAH). The sensitivity of PA to the contractile agonist could be set by relaxing signals such as the nitric oxide (NO), soluble guanylate cyclase (sGC), and cGMP-dependent kinase (PKG) pathways. Changes in the TP agonist (U46619)-induced PA contraction and its modulation by NO/cGMP signaling were analyzed in a monocrotaline-induced PAH rat model (PAH-MCT). In the myograph study, PA from PAH-MCT showed higher responsiveness to U46619, that is decreased EC50. Immunoblot analysis revealed a lower expression of eNOS, sGC, and PKG, while there was a higher expression of RhoA-dependent kinase 2 (ROCK2) in the PA from PAH-MCT than in the control. In PAH-MCT, the higher sensitivity to U46619 was reversed by 8-Br-cGMP, a membrane-permeable cGMP analog, but not by the NO donor, sodium nitroprusside (SNP 30 μM). In contrast, in the control PA, inhibition of sGC by its inhibitor (1H− [1,2,4] oxadiazolo [4,3−a] quinoxalin-1-one (ODQ), 10 μM) lowered the threshold of U46619-induced contraction. In the presence of ODQ, SNP treatment had no effect whereas the addition of 8-Br-cGMP lowered the sensitivity to U46619. The inhibition of ROCK by Y-27632 attenuated the sensitivity to U46619 in both control and PAH-MCT. The study suggests that the attenuation of NO/cGMP signaling and the upregulation of ROCK2 increase the sensitivity to TXA2 in the PAH animal, which might have pathophysiological implications in patients with PAH.

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