scholarly journals Pulmonary and systemic vasodilator responses to the soluble guanylyl cyclase activator, BAY 60–2770, are not dependent on endogenous nitric oxide or reduced heme

2011 ◽  
Vol 300 (3) ◽  
pp. H792-H802 ◽  
Author(s):  
Edward A. Pankey ◽  
Manish Bhartiya ◽  
Adeleke M. Badejo ◽  
Umair Haider ◽  
Johannes-Peter Stasch ◽  
...  

4-({(4-Carboxybutyl)[2-(5-fluoro-2-{[4′-(trifluoromethyl)biphenyl-4-yl]methoxy}phenyl)ethyl]amino}methyl)benzoic acid (BAY 60–2770) is a nitric oxide (NO)-independent activator of soluble guanylyl cyclase (sGC) that increases the catalytic activity of the heme-oxidized or heme-free form of the enzyme. In this study, responses to intravenous injections of the sGC activator BAY 60–2770 were investigated under baseline and elevated tone conditions induced by the thromboxane mimic U-46619 when NO synthesis was inhibited by Nω-nitro-l-arginine methyl ester hydrochloride (l-NAME), when sGC activity was inhibited by 1H-[1,2,4]-oxadizaolo[4,3]quinoxaline-1-one (ODQ), an agent that oxidizes sGC, and in animals with monocrotaline-induced pulmonary hypertension. The intravenous injections of BAY 60–2770 under baseline conditions caused small decreases in pulmonary arterial pressure, larger decreases in systemic arterial pressure, and no change or small increases in cardiac output. Under elevated tone conditions during infusion of U-46619, intravenous injections of BAY 60–2770 caused larger decreases in pulmonary arterial pressure, smaller decreases in systemic arterial pressure, and increases in cardiac output. Pulmonary vasodilator responses to BAY 60–2770 were enhanced by l-NAME or by ODQ in a dose that attenuated responses to the NO donor sodium nitroprusside. ODQ had no significant effect on baseline pressures and attenuated pulmonary and systemic vasodilator responses to the sGC stimulator BAY 41–8543 2-{1-[2-(fluorophenyl)methyl]-1H-pyrazolo[3,4-b]pyridin-3-yl}-5(4-morpholinyl)-4,6-pyrimidinediamine. BAY 60–2770 and sodium nitroprusside decreased pulmonary and systemic arterial pressures in monocrotaline-treated rats in a nonselective manner. The present data show that BAY 60–2770 has vasodilator activity in the pulmonary and systemic vascular beds that is enhanced by ODQ and NOS inhibition, suggesting that the heme-oxidized form of sGC can be activated in vivo in an NO-independent manner to promote vasodilation . These results show that BAY 60–2770 and sodium nitroprusside decreased pulmonary and systemic arterial pressures in monocrotaline-treated rats, suggesting that BAY 60–2770 does not have selective pulmonary vasodilator activity in animals with monocrotaline-induced pulmonary hypertension.

2010 ◽  
Vol 299 (4) ◽  
pp. H1153-H1159 ◽  
Author(s):  
Adeleke M. Badejo ◽  
Vaughn E. Nossaman ◽  
Edward A. Pankey ◽  
Manish Bhartiya ◽  
Chandrika B. Kannadka ◽  
...  

BAY 41-8543 is a nitric oxide (NO)-independent stimulator of soluble guanylyl cyclase (sGC). Responses to intravenous injections of BAY 41-8543 were investigated under baseline and elevated tone conditions and when NO synthase (NOS) was inhibited with Nω-nitro-l-arginine methyl ester (l-NAME). Under baseline conditions, intravenous injections of BAY 41-8543 caused small decreases in pulmonary arterial pressure, larger decreases in systemic arterial pressure, and increases in cardiac output. When pulmonary arterial pressure was increased to ∼30 mmHg with an intravenous infusion of U-46619, intravenous injections of BAY 41-8543 produced larger dose-dependent decreases in pulmonary arterial pressure, and the relative decreases in pulmonary and systemic arterial pressure in response to the sGC stimulator were similar. Treatment with l-NAME markedly decreased responses to BAY 41-8543 when pulmonary arterial pressure was increased to similar values (∼30 mmHg) in U-46619-infused and in U-46619-infused plus l-NAME-treated animals. The intravenous injection of a small dose of sodium nitroprusside (SNP) when combined with BAY 41-8543 enhanced pulmonary and systemic vasodilator responses to the sGC stimulator in l-NAME-treated animals. The present results indicate that BAY 41-8543 has similar vasodilator activity in the systemic and pulmonary vascular beds when pulmonary vasoconstrictor tone is increased with U-46619. These results demonstrate that pulmonary and systemic vasodilator responses to BAY 41-8543 are significantly attenuated when NOS is inhibited by l-NAME and show that vasodilator responses to BAY 41-8543 are enhanced when combined with a small dose of SNP in l-NAME-treated animals. The present results are consistent with the concept that pulmonary and systemic vasodilator responses to the sGC stimulator are NO-independent; however, the vasodilator activity of the compound is greatly diminished when endogenous NO production is inhibited with l-NAME. These data show that BAY 41-8543 has similar vasodilator activity in the pulmonary and systemic vascular beds in the rat.


1995 ◽  
Vol 268 (6) ◽  
pp. H2211-H2215 ◽  
Author(s):  
J. Heaton ◽  
B. Lin ◽  
J. K. Chang ◽  
S. Steinberg ◽  
A. Hyman ◽  
...  

The present study investigates the effects of human adrenomedullin (ADM) on the pulmonary vascular bed of isolated, blood-perfused rat lung. Because pulmonary blood flow and left atrial pressure were constant, changes in pulmonary arterial pressure directly reflect changes in pulmonary vascular resistance. Under conditions of resting (low) pulmonary vasomotor tone, intra-arterial bolus injections of ADM-(1-52) and two truncated sequences of ADM-(1-52) [ADM-(1-12) and ADM-(13-52)] did not alter pulmonary arterial pressure. When pulmonary vasomotor tone was increased by U-46619, a thromboxane A2 mimic, intra-arterial bolus injections of ADM-(1-52) and ADM-(13-52) at similar doses produced similar, dose-dependent reductions in pulmonary arterial pressure. On a molar basis, ADM-(1-52) had greater pulmonary vasodilator activity than isoproterenol. In contrast, ADM-(1-12) had no activity. When pulmonary vasomotor tone was actively increased to the same level using KCl, the pulmonary vasodilator activity of ADM-(13-52) was decreased 10-fold. The present data demonstrate that ADM-(1-52) dilates the pulmonary vascular bed and suggest that the pulmonary vasodilator activity of ADM is greater on pulmonary blood vessels preconstricted through a receptor-dependent mechanism. Because meclofenamate, nitro-L-arginine methyl ester, methysergide, BW A-1433U83, U-37883A, and calcitonin gene-related peptide [CGRP-(8-37)], a CGRP-receptor antagonist, did not alter the pulmonary vasodilator response to ADM-(1-52), the present data suggest that ADM dilates the pulmonary vascular bed independently of cyclooxygenase products, endothelium-derived relaxation factor, serotoninergic receptors, adenosine1 purinoreceptors, ATP-dependent potassium channels, and CGRP receptors.(ABSTRACT TRUNCATED AT 250 WORDS)


2007 ◽  
Vol 293 (5) ◽  
pp. L1306-L1313 ◽  
Author(s):  
Jasdeep S. Dhaliwal ◽  
David B. Casey ◽  
Anthony J. Greco ◽  
Adeleke M. Badejo ◽  
Thomas B. Gallen ◽  
...  

The small GTP-binding protein and its downstream effector Rho kinase play an important role in the regulation of vasoconstrictor tone. Rho kinase activation maintains increased pulmonary vascular tone and mediates the vasoconstrictor response to nitric oxide (NO) synthesis inhibition in chronically hypoxic rats and in the ovine fetal lung. However, the role of Rho kinase in mediating pulmonary vasoconstriction after NO synthesis inhibition has not been examined in the intact rat. To address this question, cardiovascular responses to the Rho kinase inhibitor fasudil were studied at baseline and after administration of an NO synthesis inhibitor. In the intact rat, intravenous injections of fasudil cause dose-dependent decreases in systemic arterial pressure, small decreases in pulmonary arterial pressure, and increases in cardiac output. l-NAME caused a significant increase in pulmonary and systemic arterial pressures and a decrease in cardiac output. The intravenous injections of fasudil after l-NAME caused dose-dependent decreases in pulmonary and systemic arterial pressure and increases in cardiac output, and the percent decreases in pulmonary arterial pressure in response to the lower doses of fasudil were greater than decreases in systemic arterial pressure. The Ca++ entry blocker isradipine also decreased pulmonary and systemic arterial pressure in l-NAME-treated rats. Infusion of sodium nitroprusside restored pulmonary arterial pressure to baseline values after administration of l-NAME. These data provide evidence in support of the hypothesis that increases in pulmonary and systemic vascular resistance following l-NAME treatment are mediated by Rho kinase and Ca++ entry through L-type channels, and that responses to l-NAME can be reversed by an NO donor.


2006 ◽  
Vol 290 (4) ◽  
pp. L723-L729 ◽  
Author(s):  
Oleg V. Evgenov ◽  
Cornelius J. Busch ◽  
Natalia V. Evgenov ◽  
Rong Liu ◽  
Bodil Petersen ◽  
...  

Phosphodiesterase 1 (PDE1) modulates vascular tone and the development of tolerance to nitric oxide (NO)-releasing drugs in the systemic circulation. Any role of PDE1 in the pulmonary circulation remains largely uncertain. We measured the expression of genes encoding PDE1 isozymes in the pulmonary vasculature and examined whether or not selective inhibition of PDE1 by vinpocetine attenuates pulmonary hypertension and augments the pulmonary vasodilator response to inhaled NO in lambs. Using RT-PCR, we detected PDE1A, PDE1B, and PDE1C mRNAs in pulmonary arteries and veins isolated from healthy lambs. In 13 lambs, the thromboxane A2 analog U-46619 was infused intravenously to increase mean pulmonary arterial pressure to 35 mmHg. Four animals received an intravenous infusion of vinpocetine at incremental doses of 0.3, 1, and 3 mg·kg−1·h−1. In nine lambs, inhaled NO was administered in a random order at 2, 5, 10, and 20 ppm before and after an intravenous infusion of 1 mg·kg−1·h−1 vinpocetine. Administration of vinpocetine did not alter pulmonary and systemic hemodynamics or transpulmonary cGMP or cAMP release. Inhaled NO selectively reduced mean pulmonary arterial pressure, pulmonary capillary pressure, and pulmonary vascular resistance index, while increasing transpulmonary cGMP release. The addition of vinpocetine enhanced pulmonary vasodilation and transpulmonary cGMP release induced by NO breathing without causing systemic vasodilation but did not prolong the duration of pulmonary vasodilation after NO inhalation was discontinued. Our findings demonstrate that selective inhibition of PDE1 augments the therapeutic efficacy of inhaled NO in an ovine model of acute chemically induced pulmonary hypertension.


2013 ◽  
Vol 305 (9) ◽  
pp. H1288-H1296 ◽  
Author(s):  
Edward A. Pankey ◽  
Supat Thammasiboon ◽  
George F. Lasker ◽  
Syed Baber ◽  
Joseph A. Lasky ◽  
...  

Cardiovascular responses to the tyrosine kinase inhibitor imatinib were investigated in the rat. Intravenous injections of 0.3–30 mg/kg imatinib produced small decreases in pulmonary arterial pressure, larger dose-dependent decreases in systemic arterial pressure, and no change or small increases in cardiac output, suggesting that the systemic vasodilator response is more pronounced under baseline conditions. When pulmonary arterial pressure was increased with U-46619 or Nω-nitro-l-arginine methyl ester (l-NAME), intravenous injections of imatinib produced larger dose-dependent decreases in pulmonary arterial pressure. Imatinib attenuated the acute hypoxic pulmonary vasoconstrictor response. Vasodilator responses to imatinib were not inhibited by meclofenamate, glybenclamide, or rolipram, suggesting that cyclooxygenase, ATP-sensitive K+(KATP) channels, and cAMP were not involved in mediating the response. In a 21-day prevention study, imatinib treatment (50 mg/kg ip) attenuated the increase in pulmonary arterial pressure, right ventricular hypertrophy, and small vessel remodeling induced by monocrotaline. Imatinib reduced PDGF receptor phosphorylation and PDGF-stimulated thymidine incorporation in rat pulmonary artery smooth muscle cells. These data suggest that the beneficial effect of imatinib in pulmonary hypertension may involve inhibition of PDGF tyrosine kinase receptor-mediated effects on smooth muscle cell proliferation and on vasoconstrictor tone. These results indicate that imatinib has nonselective vasodilator activity in the pulmonary and systemic vascular beds similar to the Rho kinase inhibitor fasudil and the calcium entry antagonist isradipine. The present results are consistent with the hypothesis that imatinib may inhibit a constitutively active tyrosine kinase vasoconstrictor pathway in the pulmonary and systemic vascular beds in the rat.


1993 ◽  
Vol 265 (4) ◽  
pp. H1318-H1325 ◽  
Author(s):  
J. Wong ◽  
P. A. Vanderford ◽  
J. R. Fineman ◽  
R. Chang ◽  
S. J. Soifer

The vascular endothelium mediates, in part, pulmonary vascular tone. Because endothelin-1 (ET-1), a paracrine hormone produced by vascular endothelial cells, has vasoactive properties, we investigated the hemodynamic effects of intrapulmonary injections of ET-1 in eight intact newborn lambs at rest and during pulmonary hypertension. At rest, ET-1 (50-1,000 ng/kg) did not change pulmonary arterial pressure. During pulmonary hypertension induced by the infusion of U46619 (a thromboxane A2 mimic), ET-1 (50-1,000 ng/kg) produced a selective dose-dependent decrease in pulmonary arterial pressure (5.8 +/- 3.9 to 32.9 +/- 6.9%; P < 0.05). Similarly, during pulmonary hypertension induced by alveolar hypoxia, ET-1 (50-500 ng/kg) produced a selective dose-dependent decrease in pulmonary arterial pressure (7.2 +/- 3.6 to 26.1 +/- 3.3%; P < 0.05). The decrease in pulmonary arterial pressure produced by ET-1 (250 ng/kg) was attenuated by N omega-nitro-L-arginine (an inhibitor of endothelium-derived nitric oxide synthesis, 23.7 +/- 3.4 vs. 12.5 +/- 4.7%; P < 0.05) and by glibenclamide (an ATP-gated potassium-channel blocker, 25.2 +/- 5.0 vs. 9.6 +/- 5.3%; P < 0.05) but not by meclofenamic acid (an inhibitor of prostaglandin synthesis). ET-1 is a pulmonary vasodilator during pulmonary hypertension in the intact newborn lamb. The vasodilating properties are mediated, in part, by release of endothelium-derived nitric oxide, and by activation of ATP-gated potassium channels.


1992 ◽  
Vol 72 (4) ◽  
pp. 1425-1431 ◽  
Author(s):  
D. E. Crawley ◽  
S. F. Liu ◽  
P. J. Barnes ◽  
T. W. Evans

The properties of endothelin-3 (ET-3) were investigated in isolated pulmonary artery rings and isolated blood-perfused lungs of the rat. ET-3 elicited a concentration-dependent relaxation of pulmonary artery rings, and effect inhibited by the nitric oxide synthesis inhibitor L-NG-monomethyl-L-arginine. At 0.1 microM, the response to ET-3 was biphasic, resulting in a sustained contraction. In the isolated lung, ET-3 caused a dose-dependent increase in pulmonary arterial pressure. In lungs ventilated with 3% oxygen, 10 nM ET-3 completely reversed the resultant hypoxic vasoconstriction (HPV) by 100 +/- 8%, an effect unchanged by either indomethacin (1 microM) or glibenclamide (10 microM). L-NG-monomethyl-L-arginine attenuated both the ET-3 dilation in prostaglandin F2 alpha-constricted lungs and the dose-dependent vasodilation of HPV by acetylcholine. ET-3 (10 nM) showed the response time to peak pulmonary arterial pressure generation by hypoxia, the size of the response being unchanged. These results demonstrate that ET-3 has both vasodilator and constrictor actions in the rat lung and that, like acetylcholine, the former is mediated in part via the release of nitric oxide. ET-3 also has the ability to modulate HPV.


2009 ◽  
Vol 296 (2) ◽  
pp. H524-H533 ◽  
Author(s):  
David B. Casey ◽  
Adeleke M. Badejo ◽  
Jasdeep S. Dhaliwal ◽  
Subramanyam N. Murthy ◽  
Albert L. Hyman ◽  
...  

Recent studies show that pulmonary vasodilator responses to nitrite are enhanced by hypoxia. However, the mechanism by which nitrite is converted to vasoactive nitric oxide (NO) is uncertain. In the present study, intravenous injections of sodium nitrite decreased pulmonary and systemic arterial pressures and increased cardiac output. The decreases in pulmonary arterial pressure were enhanced when tone in the pulmonary vascular bed was increased with U-46619. Under elevated tone conditions, decreases in pulmonary and systemic arterial pressures in response to nitrite were attenuated by allopurinol in a dose that did not alter responses to the NO donors, sodium nitroprusside and diethylamine/NO, suggesting that xanthine oxidoreductase is the major enzyme-reducing nitrite to NO. Ventilation with a 10% O2 gas mixture increased pulmonary arterial pressure, and the response to hypoxia was enhanced by NG-nitro-l-arginine methyl ester and not altered by allopurinol. This suggests that NO formed by the endothelium and not from the reduction of plasma nitrite modulates the hypoxic pulmonary vasoconstrictor response. Although intravenous injections of sodium nitrite reversed pulmonary hypertensive responses to U-46619, hypoxia, and NG-nitro-l-arginine methyl ester, the pulmonary vasodilator response to nitrite was not altered by ventilation with 10% O2 when baseline pulmonary arterial pressure was increased to similar values in animals breathing room air or the hypoxic gas. These data provide evidence that xanthine oxidoreductase is the major enzyme-reducing nitrite to vasoactive NO, and that this mechanism is not modified by hypoxia.


2020 ◽  
Vol 41 (8) ◽  
pp. 1651-1659
Author(s):  
Ida Jeremiasen ◽  
Karin Tran-Lundmark ◽  
Nikmah Idris ◽  
Phan-Kiet Tran ◽  
Shahin Moledina

AbstractIn children with single ventricle physiology, increased pulmonary vascular resistance may impede surgical progression or result in failing single ventricle physiology. The use of pulmonary vasodilators has been suggested as a potential therapy. However, knowledge on indication, dosage, and effect is limited. A retrospective case notes review of all (n = 36) children with single ventricle physiology, treated with pulmonary vasodilators by the UK Pulmonary Hypertension Service for Children 2004–2017. Therapy was initiated in Stage 1 (n = 12), Glenn (n = 8), or TCPC (n = 16). Treatment indications were high mean pulmonary arterial pressure, cyanosis, reduced exercise tolerance, protein-losing enteropathy, ascites, or plastic bronchitis. Average dose of sildenafil was 2.0 mg/kg/day and bosentan was 3.3 mg/kg/day. 56% had combination therapy. Therapy was associated with a reduction of the mean pulmonary arterial pressure from 19 to 14 mmHg (n = 17, p < 0.01). Initial therapy with one or two vasodilators was associated with an increase in the mean saturation from 80 to 85%, (n = 16, p < 0.01). Adding a second vasodilator did not give significant additional effect. 5 of 12 patients progressed from Stage 1 to Glenn, Kawashima, or TCPC, and 2 of 8 from Glenn to TCPC during a mean follow-up time of 4.7 years (0–12.8). Bosentan was discontinued in 57% and sildenafil in 14% of treated patients and saturations remained stable. Pulmonary vasodilator therapy was well tolerated and associated with improvements in saturation and mean pulmonary arterial pressure in children with single ventricle physiology. It appears safe to discontinue when no clear benefit is observed.


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