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Liu T, Schroeder H, Power GG, Blood AB. A physiologically relevant role for NO stored in vascular smooth muscle cells: A novel theory of vascular NO signaling. Redox Biol 2022; 53:102327. [PMID: 35605454 PMCID: PMC9126848 DOI: 10.1016/j.redox.2022.102327] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2022] [Revised: 04/16/2022] [Accepted: 04/29/2022] [Indexed: 01/16/2023] Open
Abstract
S-nitrosothiols (SNO), dinitrosyl iron complexes (DNIC), and nitroglycerine (NTG) dilate vessels via activation of soluble guanylyl cyclase (sGC) in vascular smooth muscle cells. Although these compounds are often considered to be nitric oxide (NO) donors, attempts to ascribe their vasodilatory activity to NO-donating properties have failed. Even more puzzling, many of these compounds have vasodilatory potency comparable to or even greater than that of NO itself, despite low membrane permeability. This raises the question: How do these NO adducts activate cytosolic sGC when their NO moiety is still outside the cell? In this review, we classify these compounds as ‘nitrodilators’, defined by their potent NO-mimetic vasoactivities despite not releasing requisite amounts of free NO. We propose that nitrodilators activate sGC via a preformed nitrodilator-activated NO store (NANOS) found within the vascular smooth muscle cell. We reinterpret vascular NO handling in the framework of this NANOS paradigm, and describe the knowledge gaps and perspectives of this novel model.
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Seo MS, An JR, Kang M, Heo R, Park H, Han ET, Han JH, Chun W, Park WS. Mechanisms underlying the vasodilatory effects of canagliflozin in the rabbit thoracic aorta: Involvement of the SERCA pump and Kv channels. Life Sci 2021; 287:120101. [PMID: 34715136 DOI: 10.1016/j.lfs.2021.120101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Revised: 10/13/2021] [Accepted: 10/24/2021] [Indexed: 10/20/2022]
Abstract
AIMS Canagliflozin is an anti-diabetic agent and sodium glucose co-transporter-2 inhibitor. Despite numerous clinical trials demonstrating its beneficial effects on blood pressure, the cellular mechanisms underlying the effects of canagliflozin on vascular reactivity have yet to be clarified. We investigated the vasodilatory effect of canagliflozin on aortic rings isolated from rabbits. MAIN METHODS We used rabbit thoracic aortic rings and its arterial tone was tested by using wire myography system. KEY FINDINGS Canagliflozin caused concentration-dependent vasodilation in aortic rings pre-constricted with phenylephrine or high K+. However, the degree of canagliflozin-induced vasodilation of the aortic rings pre-constricted with high K+ was less than that of rings pre-constricted with phenylephrine. Application of 4-aminopyridine, a voltage-dependent K+ (Kv) channel inhibitor, reduced canagliflozin-induced vasodilation. However, pre-incubation of an inwardly rectifying K+ channel inhibitor, a large-conductance Ca2+-activated K+ channel inhibitor, and an ATP-sensitive K+ inhibitor did not modulate the vasodilatory effects of canagliflozin. Indeed, canagliflozin increased Kv currents in aortic smooth muscle cells. Pre-treatment with thapsigargin or cyclopiazonic acid, a sarco/endoplasmic reticulum Ca2+-ATPase (SERCA) pump inhibitors, reduced the vasodilatory effects of canagliflozin. Conversely, pre-treatment with a Ca2+ channel inhibitor, adenylyl cyclase/PKA inhibitors, and guanylyl cyclase/PKG inhibitors did not modulate the vasodilatory effects of canagliflozin. Endothelium removal, and pre-treatment with the nitric oxide synthase inhibitor L-NAME, and small- and intermediate-conductance Ca2+-activated K+ channel inhibitor apamin and TRAM-34, did not diminish the vasodilatory effects of canagliflozin. SIGNIFICANCE Our results indicate that canagliflozin induces vasodilation, which is dependent on the robust SERCA activity and Kv channel activation.
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Affiliation(s)
- Mi Seon Seo
- Department of Physiology, Kangwon National University School of Medicine, Chuncheon 24341, South Korea
| | - Jin Ryeol An
- Department of Physiology, Kangwon National University School of Medicine, Chuncheon 24341, South Korea
| | - Minji Kang
- Department of Physiology, Kangwon National University School of Medicine, Chuncheon 24341, South Korea
| | - Ryeon Heo
- Department of Physiology, Kangwon National University School of Medicine, Chuncheon 24341, South Korea
| | - Hongzoo Park
- Department of Urology, Kangwon National University School of Medicine, Chuncheon 24341, South Korea
| | - Eun-Taek Han
- Department of Medical Environmental Biology and Tropical Medicine, Kangwon National University School of Medicine, Chuncheon 24341, South Korea
| | - Jin-Hee Han
- Department of Medical Environmental Biology and Tropical Medicine, Kangwon National University School of Medicine, Chuncheon 24341, South Korea
| | - Wanjoo Chun
- Department of Pharmacology, Kangwon National University School of Medicine, Chuncheon 24341, South Korea
| | - Won Sun Park
- Department of Physiology, Kangwon National University School of Medicine, Chuncheon 24341, South Korea.
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Shpakova V, Rukoyatkina N, Walter U, Gambaryan S. Potential and limitations of PKA/ PKG inhibitors for platelet studies. Platelets 2021; 33:859-868. [PMID: 34845961 DOI: 10.1080/09537104.2021.2003316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Cyclic nucleotides (cAMP and cGMP) and corresponding protein kinases, protein kinase A (PKA) and protein kinase G (PKG), are the main intracellular mediators of endothelium-derived platelet inhibitors. Pharmacological PKA/PKG inhibitors are often used to discriminate between these two kinase activities and to analyze their underlying mechanisms. Previously we showed that all widely used PKG inhibitors (KT5823, DT3, RP isomers) either did not inhibit PKG or inhibited and even activated platelets independently from PKG. In this study, we examined several PKA inhibitors as well as inhibitors of adenylate and guanylate cyclases to reveal their effects on platelets and establish whether they are mediated by PKA/PKG. The commonly used PKA inhibitor H89 inhibited both PKA and PKG but PKA-independently inhibited thrombin-induced platelet activation. In our experiments, KT5720 did not inhibit PKA and had no effect on platelet activation. PKI inhibited PKA activity in platelets but also strongly PKA-independently activated platelets. Inhibition of adenylate and guanylate cyclases may be an alternative approach to analyze PKA/PKG function. Based on our previous and presented data, we conclude that all results where the mentioned PKA inhibitors were used for the analysis of PKA activity in intact platelets should be considered with caution.
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Affiliation(s)
- Valentina Shpakova
- Laboratory of cellular mechanisms of blood homeostasis, Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Sciences, Saint Petersburg, Russia
| | - Natalia Rukoyatkina
- Laboratory of cellular mechanisms of blood homeostasis, Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Sciences, Saint Petersburg, Russia
| | - Ulrich Walter
- Center for Thrombosis and Hemostasis (CTH), University Medical Center Mainz of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Stepan Gambaryan
- Laboratory of cellular mechanisms of blood homeostasis, Sechenov Institute of Evolutionary Physiology and Biochemistry of the Russian Academy of Sciences, Saint Petersburg, Russia
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4
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Tegin G, Gao Y, Hamlyn JM, Clark BJ, El-Mallakh RS. Inhibition of endogenous ouabain by atrial natriuretic peptide is a guanylyl cyclase independent effect. PLoS One 2021; 16:e0260131. [PMID: 34793577 PMCID: PMC8601428 DOI: 10.1371/journal.pone.0260131] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2021] [Accepted: 11/03/2021] [Indexed: 12/15/2022] Open
Abstract
Background Endogenous ouabain (EO) and atrial natriuretic peptide (ANP) are important in regulation of sodium and fluid balance. There is indirect evidence that ANP may be involved in the regulation of endogenous cardenolides. Methods H295R are human adrenocortical cells known to release EO. Cells were treated with ANP at physiologic concentrations or vehicle (0.1% DMSO), with or without guanylyl cyclase inhibitor 1,2,4 oxadiazolo[4,3-a]quinoxalin-1-one (ODQ). Cyclic guanosine monophosphate (cGMP), the intracellular second messenger of ANP, was measured by a chemiluminescent immunoassay and EO was measured by radioimmunoassay of C18 extracted samples. Results EO secretion is inhibited by ANP treatment, with the most prolonged inhibition (90 min vs ≤ 60 min) occurring at physiologic ANP concentrations (50 pg/mL). Inhibition of guanylyl cyclase with ODQ, also reduces EO secretion. The inhibitory effects on EO release in response to cotreatment with ANP and ODQ appeared to be additive. Conclusions ANP inhibits basal EO secretion, and it is unlikely that this is mediated through ANP-A or ANP-B receptors (the most common natriuretic peptide receptors) or their cGMP second messenger; the underlying mechanisms involved are not revealed in the current studies. The role of ANP in the control of EO synthesis and secretion in vivo requires further investigation.
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Affiliation(s)
- Gulay Tegin
- Department of Psychiatry and Behavioral Sciences, University of Louisville, Louisville, Kentucky, United States of America
| | - Yonglin Gao
- Department of Psychiatry and Behavioral Sciences, University of Louisville, Louisville, Kentucky, United States of America
| | - John M. Hamlyn
- Department of Physiology, School of Medicine, University of Maryland, Baltimore, Mississippi, United States of America
| | - Barbara J. Clark
- Department of Biochemistry and Molecular Genetics, University of Louisville, Louisville, Kentucky, United States of America
| | - Rif S. El-Mallakh
- Department of Psychiatry and Behavioral Sciences, University of Louisville, Louisville, Kentucky, United States of America
- * E-mail:
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Lewis THJ, Getsy PM, Peroni JF, Ryan RM, Jenkins MW, Lewis SJ. Characterization of endothelium-dependent and -independent processes in occipital artery of the rat: Relevance to control of blood flow to nodose sensory cells. J Appl Physiol (1985) 2021; 131:1067-1079. [PMID: 34323595 DOI: 10.1152/japplphysiol.00221.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Circulating factors access cell bodies of vagal afferents in nodose ganglia (NG) via the occipital artery (OA). Constrictor responses of OA segments closer in origin from the external carotid artery (ECA) differ from segments closer to NG. Our objective was to determine the role of endothelium in this differential vasoreactivity in rat OA segments. Vasoreactivity of OA segments (proximal segments closer to ECA, distal segments closer to NG) were examined in wire myographs. We evaluated (a) vasoconstrictor effects of 5-hydroxytryptamine (5-HT) in intact and endothelium-denuded OA segments in absence/presence of soluble guanylate cyclase (SGC) inhibitor ODQ, (b) vasodilator responses elicited by NO-donor MAHMA NONOate in intact or endothelium-denuded OA segments in absence/presence of ODQ, and (c) vasodilator responses elicited by endothelium-dependent vasodilator, acetylcholine (ACh), in intact OA segments in absence/presence of ODQ. Intact distal OA responded more to 5-HT than intact proximal OA. Endothelium denudation increased 5-HT potency in both OA segments, especially proximal OA. ODQ increased maximal responses of 5HT in both segments, particularly proximal OA. ACh similarly relaxed both OA segments, effects abolished by endothelial denudation and attenuated by ODQ. MAHMA NONOate elicited transient vasodilation in both segments. Effects of ODQ against ACh were segment-dependent whereas those against MAHMA NONOate were not. The endothelium regulates OA responsiveness in a segment-dependently fashion. Endothelial cells at the OA-ECA junction more strongly influence vascular tone than those closer to NG. Differential endothelial regulation of OA tone may play a role in controlling blood flow and access of circulating factors to NG.
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Affiliation(s)
- Tristan H J Lewis
- Department of Biology, Case Western Reserve University, Cleveland, OH, United States
| | - Paulina M Getsy
- Department of Pediatrics, Case Western Reserve University, Cleveland, OH, United States
| | - John F Peroni
- Department of Large Animal Medicine, University of Georgia, Athens, Georgia, United States
| | - Rita M Ryan
- Department of Pediatrics, Case Western Reserve University, Cleveland, OH, United States
| | - Michael W Jenkins
- Department of Pediatrics, Case Western Reserve University, Cleveland, OH, United States.,Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States
| | - Stephen John Lewis
- Department of Pediatrics, Case Western Reserve University, Cleveland, OH, United States.,Department of Pharmacology, Case Western Reserve University, Cleveland, OH, United States.,Functional Electrical Stimulation Center, Case Western Reserve University, Cleveland, OH, United States
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Fast Isolation of Flavonoids from the Endemic Species Nolana ramosissima I.M. Johnst and Its Endothelium-Independent Relaxation Effect in Rat Aorta. Molecules 2020; 25:molecules25030520. [PMID: 31991709 PMCID: PMC7036828 DOI: 10.3390/molecules25030520] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Revised: 01/15/2020] [Accepted: 01/19/2020] [Indexed: 12/20/2022] Open
Abstract
The infusion of the desertic plant Nolana ramosissima I.M. Johnst showed vascular smooth muscle relaxation in rat aorta and the presence of several phenolic compounds, which were detected by high resolution UHPLC-Orbitrap-HESI-MS. In addition, five flavonoids were rapidly isolated from a methanolic extract using high-performance counter-current chromatography (HPCCC). The N. ramosissima extract showed endothelium-independent relaxation effect in rat aorta. Sixty-one compounds were detected in the infusion, mainly glycosylated flavonoids, flavanones and several oxylipins, suggesting that a synergistic effect between the compounds in the extracts could be responsible for the relaxation activity. Vascular activity experiments were done in isolated organ bath. In rat aorta, a nitric oxide inhibitor did not prevent the relaxation effects of the extract; however, a selective guanylyl cyclase inhibitor partially blunted this effect. The compound 5,3′-dihydroxy-4′7-dimethoxyflavone presented higher relaxation effect than 100 μg/mL of N. ramosissima extract. The extract and the isolated metabolites from N. ramosissima can show relaxation effects on rat aorta by a mechanism that is independent of the endothelium.
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Ahmad T, Shah AJ, Roberts R. Mechanisms mediating the vasodilatory effects of juglone in porcine isolated coronary artery. Eur J Pharmacol 2019; 866:172815. [PMID: 31747546 DOI: 10.1016/j.ejphar.2019.172815] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 11/15/2019] [Accepted: 11/15/2019] [Indexed: 02/07/2023]
Abstract
Juglone (5-hydroxy-1, 4-naphthoquinone), is a natural phenolic compound that has been shown to relax smooth muscle. Therefore the aim of this study was to determine the effect of juglone on vascular tone using porcine coronary artery (PCA). Segments of PCA, with or without endothelium, were mounted for isometric tension recording in isolated tissue baths and precontracted with the thromboxane A2 analog U46619 or KCl. After pre-contraction, cumulative concentrations of juglone were added to the tissues, in the presence or absence of a variety of inhibitors on intracellular signaling pathways. Juglone (10-9 to 10-5 M) produced a concentration-dependent relaxation of the PCA which was reduced in endothelium-denuded vessels, as well as in vessels pre-treated with the nitric oxide synthase inhibitor L-NAME, indicating that at least part of the effect of juglone is mediated through an endothelium, NO-dependent mechanism. Juglone also inhibited contractions in response to influx of extracellular calcium and release of intracellular calcium, indicating that juglone may inhibit a common signaling pathway downstream of calcium. Contractions to the protein kinase C activator Phorbol 12-myristate 13-acetate were also reduced by juglone, suggesting that juglone might be acting through inhibition of protein kinase C. In summary, juglone produces a relaxation of the porcine coronary artery through activation of the nitric oxide pathway and inhibition of calcium-induced contractions.
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Affiliation(s)
- Taseer Ahmad
- Department of Pharmacy, COMSATS University Islamabad, Abbottabad Campus, University Road, Abbottabad, KPK-22060, Pakistan; Department of Pharmacology, College of Pharmacy, University of Sargodha, University Road, Sargodha, Punjab, 40100, Pakistan; School of Life Sciences, University of Nottingham Medical School, Queen's Medical Centre, Nottingham, NG7 2UH, UK
| | - Abdul Jabbar Shah
- Department of Pharmacy, COMSATS University Islamabad, Abbottabad Campus, University Road, Abbottabad, KPK-22060, Pakistan
| | - Richard Roberts
- School of Life Sciences, University of Nottingham Medical School, Queen's Medical Centre, Nottingham, NG7 2UH, UK.
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Liu T, Zhang M, Mukosera GT, Borchardt D, Li Q, Tipple TE, Ishtiaq Ahmed AS, Power GG, Blood AB. L-NAME releases nitric oxide and potentiates subsequent nitroglycerin-mediated vasodilation. Redox Biol 2019; 26:101238. [PMID: 31200239 PMCID: PMC6565607 DOI: 10.1016/j.redox.2019.101238] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 05/27/2019] [Accepted: 06/02/2019] [Indexed: 12/22/2022] Open
Abstract
L-NG-Nitro arginine methyl ester (L-NAME) has been widely applied for several decades in both basic and clinical research as an antagonist of nitric oxide synthase (NOS). Herein, we show that L-NAME slowly releases NO from its guanidino nitro group. Daily pretreatment of rats with L-NAME potentiated mesenteric vasodilation induced by nitrodilators such as nitroglycerin, but not by NO. Release of NO also occurred with the NOS-inactive enantiomer D-NAME, but not with L-arginine or another NOS inhibitor L-NMMA, consistent with the presence or absence of a nitro group in their structure and their nitrodilator-potentiating effects. Metabolic conversion of the nitro group to NO-related breakdown products was confirmed using isotopically-labeled L-NAME. Consistent with Fenton chemistry, transition metals and reactive oxygen species accelerated the release of NO from L-NAME. Both NO production from L-NAME and its nitrodilator-potentiating effects were augmented under inflammation. NO release by L-NAME can confound its intended NOS-inhibiting effects, possibly by contributing to a putative intracellular NO store in the vasculature. NOS-inhibitor L-NAME is also a precursor of NO. ROS releases NO from the nitro group of L-NAME via Fenton Chemistry. L-NAME potentates nitrodilator-mediated vasodilation. Nitroglycerin may cause vasodilation via activation of an intracellular NO store.
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Affiliation(s)
- Taiming Liu
- Department of Pediatrics, Loma Linda University School of Medicine, Loma Linda, CA, 92354, USA
| | - Meijuan Zhang
- Department of Pediatrics, Loma Linda University School of Medicine, Loma Linda, CA, 92354, USA
| | - George T Mukosera
- Department of Pediatrics, Loma Linda University School of Medicine, Loma Linda, CA, 92354, USA
| | - Dan Borchardt
- Department of Chemistry, University of California, Riverside, CA, 92521, USA
| | - Qian Li
- Neonatal Redox Biology Laboratory, Department of Pediatrics, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Trent E Tipple
- Neonatal Redox Biology Laboratory, Department of Pediatrics, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | | | - Gordon G Power
- Lawrence D. Longo Center for Perinatal Biology, Loma Linda University School of Medicine, Loma Linda, CA, 92354, USA
| | - Arlin B Blood
- Department of Pediatrics, Loma Linda University School of Medicine, Loma Linda, CA, 92354, USA; Lawrence D. Longo Center for Perinatal Biology, Loma Linda University School of Medicine, Loma Linda, CA, 92354, USA.
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Mateus LS, Albuquerque AAS, Celotto AC, Evora PRB. In vitro evidence that endothelium-dependent vasodilatation induced by clozapine is mediated by an ATP-sensitive potassium channel. Pharmacol Rep 2019; 71:522-527. [PMID: 31015092 DOI: 10.1016/j.pharep.2019.02.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Revised: 01/19/2019] [Accepted: 02/15/2019] [Indexed: 10/27/2022]
Abstract
BACKGROUND There is a definite association between antipsychotic drugs and arterial hypertension. However, endothelium functions are scarcely considered. This investigation was carried out to study the mechanisms involved in clozapine endothelium-dependent vascular reactivity. METHODS The experimental animals were male Wistar rats with a mean age of 70-90 days (250-300 g). The endothelium-dependent vascular reactivity was studied by measuring the isometric force and then constructing clozapine concentration-response curves. The force registrations were obtained in the aorta rings with and without the endothelium precontracted with phenylephrine (PE10-6M) treatment; this followed incubation for 30 min in "organ chambers" with different inhibitors: l- NAME (nitric oxide/cGMP); indomethacin (PGI2/cAMP); tetraethylammonium (TEA), and specific hyperpolarization blockers (paxillin, apamin, glibenclamide). The data were presented as the mean ± standard error of the mean (SEM) and were compared by one-way ANOVA or two-way ANOVA followed by the Bonferroni post-test. RESULTS The primary outcomes were: 1) Clozapine-induced endothelium-dependent relaxation was not inhibited by indomethacin, l-NAME, ODQ, and methylene blue (MB); 2) The combination of l-NAME + indomethacin partially prevented the relaxation; 3) Clozapine did not induce relaxation in vessels contracted with KCl; 4) TEA did not block the clozapine-induced relaxation in vessels precontracted with PE (10-6 M); 5) The potassium channel blockers paxillin and apamin did not prevent relaxation but glibenclamide did. CONCLUSION Concerning the mechanisms involved in clozapine endothelium-dependent vascular reactivity, the present study suggests that there is synergistic participation that probably occurs through a crosstalk mechanism of the cAMP, cGMPpathways and hyperpolarization.
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Affiliation(s)
- Luiza Silva Mateus
- Department of Surgery and Anatomy, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil
| | | | - Andrea Carla Celotto
- Department of Surgery and Anatomy, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil
| | - Paulo Roberto Barbosa Evora
- Department of Surgery and Anatomy, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil.
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Hollas MA, Ben Aissa M, Lee SH, Gordon-Blake JM, Thatcher GRJ. Pharmacological manipulation of cGMP and NO/cGMP in CNS drug discovery. Nitric Oxide 2018; 82:59-74. [PMID: 30394348 DOI: 10.1016/j.niox.2018.10.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Revised: 08/14/2018] [Accepted: 10/25/2018] [Indexed: 12/21/2022]
Abstract
The development of small molecule modulators of NO/cGMP signaling for use in the CNS has lagged far behind the use of such clinical agents in the periphery, despite the central role played by NO/cGMP in learning and memory, and the substantial evidence that this signaling pathway is perturbed in neurodegenerative disorders, including Alzheimer's disease. The NO-chimeras, NMZ and Nitrosynapsin, have yielded beneficial and disease-modifying responses in multiple preclinical animal models, acting on GABAA and NMDA receptors, respectively, providing additional mechanisms of action relevant to synaptic and neuronal dysfunction. Several inhibitors of cGMP-specific phosphodiesterases (PDE) have replicated some of the actions of these NO-chimeras in the CNS. There is no evidence that nitrate tolerance is a phenomenon relevant to the CNS actions of NO-chimeras, and studies on nitroglycerin in the periphery continue to challenge the dogma of nitrate tolerance mechanisms. Hybrid nitrates have shown much promise in the periphery and CNS, but to date only one treatment has received FDA approval, for glaucoma. The potential for allosteric modulation of soluble guanylate cyclase (sGC) in brain disorders has not yet been fully explored nor exploited; whereas multiple applications of PDE inhibitors have been explored and many have stalled in clinical trials.
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Affiliation(s)
- Michael A Hollas
- Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois at Chicago, Chicago, USA
| | - Manel Ben Aissa
- Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois at Chicago, Chicago, USA
| | - Sue H Lee
- Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois at Chicago, Chicago, USA
| | - Jesse M Gordon-Blake
- Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois at Chicago, Chicago, USA
| | - Gregory R J Thatcher
- Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, University of Illinois at Chicago, Chicago, USA.
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12
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Liu T, Zhang M, Terry MH, Schroeder H, Wilson SM, Power GG, Li Q, Tipple TE, Borchardt D, Blood AB. Nitrite potentiates the vasodilatory signaling of S-nitrosothiols. Nitric Oxide 2018; 75:60-69. [PMID: 29428841 DOI: 10.1016/j.niox.2018.01.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2017] [Revised: 01/30/2018] [Accepted: 01/31/2018] [Indexed: 12/27/2022]
Abstract
Nitrite and S-nitrosothiols (SNOs) are both byproducts of nitric oxide (NO) metabolism and are proposed to cause vasodilation via activation of soluble guanylate cyclase (sGC). We have previously reported that while SNOs are potent vasodilators at physiological concentrations, nitrite itself only produces vasodilation at supraphysiological concentrations. Here, we tested the hypothesis that sub-vasoactive concentrations of nitrite potentiate the vasodilatory effects of SNOs. Multiple exposures of isolated sheep arteries to S-nitroso-glutathione (GSNO) resulted in a tachyphylactic decreased vasodilatory response to GSNO but not to NO, suggesting attenuation of signaling steps upstream from sGC. Exposure of arteries to 1 μM nitrite potentiated the vasodilatory effects of GSNO in naive arteries and abrogated the tachyphylactic response to GSNO in pre-exposed arteries, suggesting that nitrite facilitates GSNO-mediated activation of sGC. In intact anesthetized sheep and rats, inhibition of NO synthases to decrease plasma nitrite levels attenuated vasodilatory responses to exogenous infusions of GSNO, an effect that was reversed by exogenous infusion of nitrite at sub-vasodilating levels. This study suggests nitrite potentiates SNO-mediated vasodilation via a mechanism that lies upstream from activation of sGC.
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Affiliation(s)
- Taiming Liu
- Division of Neonatology, Department of Pediatrics, Loma Linda University School of Medicine, Loma Linda, CA 92354, United States
| | - Meijuan Zhang
- Division of Neonatology, Department of Pediatrics, Loma Linda University School of Medicine, Loma Linda, CA 92354, United States
| | - Michael H Terry
- Department of Respiratory Care, Loma Linda University School of Medicine, Loma Linda, CA 92354, United States
| | - Hobe Schroeder
- Center for Perinatal Biology, Loma Linda University School of Medicine, Loma Linda, CA 92354, United States
| | - Sean M Wilson
- Center for Perinatal Biology, Loma Linda University School of Medicine, Loma Linda, CA 92354, United States
| | - Gordon G Power
- Center for Perinatal Biology, Loma Linda University School of Medicine, Loma Linda, CA 92354, United States
| | - Qian Li
- Neonatal Redox Biology Laboratory, Division of Neonatology, University of Alabama at Birmingham, Birmingham, AL 35294, United States
| | - Trent E Tipple
- Neonatal Redox Biology Laboratory, Division of Neonatology, University of Alabama at Birmingham, Birmingham, AL 35294, United States
| | - Dan Borchardt
- Department of Chemistry, University of California, Riverside, CA 92521, United States
| | - Arlin B Blood
- Division of Neonatology, Department of Pediatrics, Loma Linda University School of Medicine, Loma Linda, CA 92354, United States; Center for Perinatal Biology, Loma Linda University School of Medicine, Loma Linda, CA 92354, United States.
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Jimenez M, Gil V, Martinez‐Cutillas M, Mañé N, Gallego D. Hydrogen sulphide as a signalling molecule regulating physiopathological processes in gastrointestinal motility. Br J Pharmacol 2017; 174. [PMID: 28631296 PMCID: PMC5554320 DOI: 10.1111/bph.13918] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The biology of H2 S is a still developing area of research and several biological functions have been recently attributed to this gaseous molecule in many physiological systems, including the cardiovascular, urogenital, respiratory, digestive and central nervous system (CNS). H2 S exerts anti-inflammatory effects and can be considered an endogenous mediator with potential effects on gastrointestinal motility. During the last few years, we have investigated the role of H2 S as a regulator of gastrointestinal motility using both animal and human tissues. The aim of the present work is to review published data regarding the potential role of H2 S as a signalling molecule regulating physiopathological processes in gastrointestinal motor function. H2 S is endogenously produced by defined enzymic pathways in different cell types of the intestinal wall including neurons and smooth muscle. Inhibition of H2 S biosynthesis increases motility and H2 S donors cause smooth muscle relaxation and inhibition of propulsive motor patterns. Impaired H2 S production has been described in animal models with gastrointestinal motor dysfunction. The mechanism(s) of action underlying these effects may include several ion channels, although no specific receptor has been identified. At this time, even though there is much experimental evidence for H2 S as a modulator of gastrointestinal motility, we still do not have conclusive experimental evidence to definitively propose H2 S as an inhibitory neurotransmitter in the gastrointestinal tract, causing nerve-mediated relaxation.
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Affiliation(s)
- M Jimenez
- Department of Cell Biology, Physiology and Immunology and Neuroscience InstituteUniversitat Autònoma de BarcelonaBarcelonaSpain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd)Instituto de Salud Carlos IIIBarcelonaSpain
| | - V Gil
- Department of Cell Biology, Physiology and Immunology and Neuroscience InstituteUniversitat Autònoma de BarcelonaBarcelonaSpain
| | - M Martinez‐Cutillas
- Department of Cell Biology, Physiology and Immunology and Neuroscience InstituteUniversitat Autònoma de BarcelonaBarcelonaSpain
| | - N Mañé
- Department of Cell Biology, Physiology and Immunology and Neuroscience InstituteUniversitat Autònoma de BarcelonaBarcelonaSpain
| | - D Gallego
- Department of Cell Biology, Physiology and Immunology and Neuroscience InstituteUniversitat Autònoma de BarcelonaBarcelonaSpain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd)Instituto de Salud Carlos IIIBarcelonaSpain
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Pinkney AMH, Lemmey HAL, Dora KA, Garland CJ. Vasorelaxation to the Nitroxyl Donor Isopropylamine NONOate in Resistance Arteries Does Not Require Perivascular Calcitonin Gene-Related Peptide. Hypertension 2017; 70:HYPERTENSIONAHA.117.09737. [PMID: 28760938 DOI: 10.1161/hypertensionaha.117.09737] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Revised: 05/28/2017] [Accepted: 07/05/2017] [Indexed: 01/12/2023]
Abstract
Nitroxyl (HNO) donors offer considerable therapeutic potential for the treatment of hypertension-related cardiovascular disorders, particularly heart failure, as they combine an inotropic action with peripheral vasodilation. Angeli's salt is the only HNO donor whose mechanism has been studied in depth, and recently, Angeli's salt vasodilation was suggested to be indirect and caused by calcitonin gene-related peptide (CGRP) released from perivascular nerves after HNO activates TRPA1 (transient receptor potential cation channel subfamily A member 1) channels. We investigated resistance artery vasorelaxation to the HNO donor, isopropylamine NONOate (IPA/NO), one of the structures providing a template for therapeutic development. Wire myography in combination with measurements of smooth muscle membrane potential was used to characterize the effect of IPA/NO in mesenteric resistance arteries. Immunohistochemistry was assessed in pressurized arteries. IPA/NO concentration dependently hyperpolarized and relaxed arteries precontracted with the α1-adrenoreceptor agonist, phenylephrine. These effects were blocked by the soluble guanylyl cyclase inhibitor, ODQ (1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one) but not by the KATP channel inhibitor, glibenclamide. Vasorelaxation persisted in the presence of raised [K+]o, used to block hyperpolarization, capsaicin to deplete perivascular CGRP, or HC030031 (2-(1,3-dimethyl-2,6-dioxo-1,2,3,6-tetrahydro-7H-purin-7-yl)-N-(4 isopropylphenyl) acetamide) to block TRPA1 receptors. Without preconstriction, hyperpolarization to IPA/NO was suppressed by glibenclamide, capsaicin, or HC030031. Hyperpolarization but not vasorelaxation to exogenous CGRP was inhibited with glibenclamide. Thus, vascular hyperpolarization is not necessary for vasorelaxation to the HNO donor IPA/NO, even though both effects are cGMP dependent. The reduced hyperpolarization after depletion of perivascular CGRP or block of TRPA1 receptors indicates some release of CGRP, but this does not contribute to HNO vasorelaxation. Therefore, HNO-TRPA1-CGRP signaling does not seem important for vasodilation to IPA/NO in resistance arteries.
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Affiliation(s)
- Alice M H Pinkney
- From the Department of Pharmacology, University of Oxford, United Kingdom
| | - Hamish A L Lemmey
- From the Department of Pharmacology, University of Oxford, United Kingdom
| | - Kim A Dora
- From the Department of Pharmacology, University of Oxford, United Kingdom
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15
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Boydens C, Pauwels B, Vanden Daele L, Van de Voorde J. Inhibition of Cyclic GMP Export by Multidrug Resistance Protein 4: A New Strategy to Treat Erectile Dysfunction? J Sex Med 2017; 14:502-509. [PMID: 28258955 DOI: 10.1016/j.jsxm.2017.02.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 01/27/2017] [Accepted: 02/03/2017] [Indexed: 12/27/2022]
Abstract
BACKGROUND Intracellular cyclic guanosine monophosphate (cGMP) concentrations are regulated by degradation enzymes (phosphodiesterases) and by active transport across the plasma membrane by multidrug resistance proteins (MRPs) 4 and 5. AIM To evaluate the functional effect of MRP-4 inhibition and the role of MRP-4-mediated cGMP export in mouse corpora cavernosa. METHODS Isometric tension of mouse corpora cavernosa was measured after cumulative addition of MK-571, an inhibitor of MRP-4, or sildenafil, a phosphodiesterase type 5 inhibitor. In addition, the effect of MRP-4 inhibition on cGMP-independent and cGMP-dependent relaxations was studied. In vivo intracavernosal pressure and mean arterial pressure measurements were performed after intracavernosal injection of MK-571. The effect of MRP-4 inhibition on cGMP content was determined using an enzyme immunoassay kit. OUTCOMES Measurement of the effect of MK-571 on cGMP content, relaxant responses of mouse corpora cavernosa to cGMP-independent and cGMP-dependent vasodilating substances, and determination of the ratio of intracavernosal pressure to mean arterial pressure after intracavernosal injection of MK-571. RESULTS MK-571 and sildenafil relaxed the corpora cavernosa concentration dependently, with sildenafil being the more potent relaxing compound. Furthermore, MK-571 enhanced relaxing responses to cGMP-dependent substances, such as sodium nitroprusside, sildenafil, acetylcholine, and electrical field stimulation, with the latter even under in vitro diabetic conditions. In contrast, cGMP-independent relaxations were not altered by MRP-4 inhibition. Intracavernosal administration of MK-571 significantly increased intracavernosal pressure, with minimal effect on mean arterial pressure. The cGMP analysis showed that MRP-4 inhibition was accompanied by increased cGMP levels. CLINICAL TRANSLATION MRP-4, at least when targeted locally in the penis or when combined with a phosphodiesterase type 5 inhibitor, might be a valuable alternative strategy for the treatment of (diabetic) erectile dysfunction. STRENGTHS AND LIMITATIONS This study is the first to demonstrate an in vitro direct relaxant and an in vivo pro-erectile effect of the MRP-4 inhibitor, MK-571, on mouse corpora cavernosa. However, the functional effect of MRP-5-mediated export in mouse corpora cavernosa was not explored, which has been suggested to play the predominant role in cGMP export. CONCLUSION Inhibition of MRP-4 increases basal and stimulated levels of cGMP, leading to corpora cavernosa relaxation and penile erection. Therefore, in addition to degradation of cGMP, export of cGMP by MRP-4 could contribute substantially to regulating cGMP levels in mouse corpora cavernosa. Boydens C, Pauwels B, Vanden Daele L, Van de Voorde J. Inhibition of Cyclic GMP Export by Multidrug Resistance Protein 4: A New Strategy to Treat Erectile Dysfunction? J Sex Med 2017;14:502-509.
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Affiliation(s)
| | - Bart Pauwels
- Department of Pharmacology, Ghent University, Ghent, Belgium
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16
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Vijayaraghavan J, Kramp K, Harris ME, van den Akker F. Inhibition of soluble guanylyl cyclase by small molecules targeting the catalytic domain. FEBS Lett 2016; 590:3669-3680. [PMID: 27654641 DOI: 10.1002/1873-3468.12427] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Revised: 08/29/2016] [Accepted: 09/09/2016] [Indexed: 12/23/2022]
Abstract
Soluble guanylyl cyclase (sGC) plays a crucial role in cyclic nucleotide signaling that regulates numerous important physiological processes. To identify new sGC inhibitors that may prevent the formation of the active catalytic domain conformation, we carried out an in silico docking screen targeting a 'backside pocket' of the inactive sGC catalytic domain structure. Compounds 1 and 2 were discovered to inhibit sGC even at high/saturating nitric oxide concentrations. Both compounds also inhibit the BAY 58-2667-activated sGC as well as BAY 41-2272-stimulated sGC activity. Additional biochemical analyses showed that compound 2 also inhibits the isolated catalytic domain, thus demonstrating functional binding to this domain. Both compounds have micromolar affinity for sGC and are potential leads to develop more potent sGC inhibitors.
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Affiliation(s)
| | - Kristopher Kramp
- Department of Biochemistry, Case Western Reserve University, Cleveland, OH, USA
| | - Michael E Harris
- Department of Biochemistry, Case Western Reserve University, Cleveland, OH, USA
| | - Focco van den Akker
- Department of Biochemistry, Case Western Reserve University, Cleveland, OH, USA.
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17
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Gerber L, Jensen FB, Madsen SS, Marshall WS. Nitric oxide inhibition of NaCl secretion in the opercular epithelium of seawater-acclimated killifish, Fundulus heteroclitus. ACTA ACUST UNITED AC 2016; 219:3455-3464. [PMID: 27591310 DOI: 10.1242/jeb.145045] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Accepted: 08/22/2016] [Indexed: 11/20/2022]
Abstract
Nitric oxide (NO) modulates epithelial ion transport pathways in mammals, but this remains largely unexamined in fish. We explored the involvement of NO in controlling NaCl secretion by the opercular epithelium of seawater killifish using an Ussing chamber approach. Pharmacological agents were used to explore the mechanism(s) triggering NO action. A modified Biotin-switch technique was used to investigate S-nitrosation of proteins. Stimulation of endogenous NO production via the nitric oxide synthase (NOS) substrate l-arginine (2.0 mmol l-1), and addition of exogenous NO via the NO donor SNAP (10-6 to 10-4 mol l-1), decreased the epithelial short-circuit current (Isc). Inhibition of endogenous NO production by the NOS inhibitor l-NAME (10-4 mol l-1) increased Isc and revealed a tonic control of ion transport by NO in unstimulated opercular epithelia. The NO scavenger PTIO (10-5 mol l-1) supressed the NO-mediated decrease in Isc, and confirmed that the effect observed was elicited by release of NO. The effect of SNAP on Isc was abolished by inhibitors of the soluble guanylyl cyclase (sGC), ODQ (10-6 mol l-1) and Methylene Blue (10-4 mol l-1), revealing NO signalling via the sGC/cGMP pathway. Incubation of opercular epithelium and gill tissues with SNAP (10-4 mol l-1) led to S-nitrosation of proteins, including Na+/K+-ATPase. Blocking of NOS with l-NAME (10-6 mol l-1) or scavenging of NO with PTIO during hypotonic shock suggested an involvement of NO in the hypotonic-mediated decrease in Isc Yohimbine (10-4 mol l-1), an inhibitor of α2-adrenoceptors, did not block NO effects, suggesting that NO is not involved in the α-adrenergic control of NaCl secretion.
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Affiliation(s)
- Lucie Gerber
- Department of Biology, University of Southern Denmark, Odense M DK-5230, Denmark
| | - Frank B Jensen
- Department of Biology, University of Southern Denmark, Odense M DK-5230, Denmark
| | - Steffen S Madsen
- Department of Biology, University of Southern Denmark, Odense M DK-5230, Denmark
| | - William S Marshall
- Department of Biology, St Francis Xavier University, Antigonish, NS, Canada B2G 2W5
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18
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Mañé N, Viais R, Martínez-Cutillas M, Gallego D, Correia-de-Sá P, Jiménez M. Inverse gradient of nitrergic and purinergic inhibitory cotransmission in the mouse colon. Acta Physiol (Oxf) 2016; 216:120-31. [PMID: 26347033 DOI: 10.1111/apha.12599] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Revised: 07/09/2015] [Accepted: 09/02/2015] [Indexed: 02/06/2023]
Abstract
AIM Gastrointestinal smooth muscle relaxation is accomplished by the neural corelease of ATP or a related purine and nitric oxide. Contractions are triggered by acetylcholine and tachykinins. The aim of this work was to study whether regional differences in neurotransmission could partially explain the varied physiological roles of each colonic area. METHODS We used electrophysiological and myography techniques to evaluate purinergic (L-NNA 1 mm incubated tissue), nitrergic (MRS2500 0.3 μm incubated tissue) and cholinergic neurotransmission (L-NNA 1 mm and MRS2500 0.3 μm incubated tissue) in the proximal, mid and distal colon of CD1 mice (n = 42). RESULTS Purinergic electrophysiological responses elicited by single pulses (28 V) were greater in the distal (IJPfMAX = -35.3 ± 2.2 mV), followed by the mid (IJPfMAX = -30.6 ± 1.0 mV) and proximal (IJPfMAX = -11.7 ± 1.1 mV) colon. In contrast, nitrergic responses decreased from the proximal colon (IJPsMAX = -11.4 ± 1.1 mV) to the mid (IJPsMAX = -9.1 ± 0.4 mV), followed by the distal colon (IJPsMAX = -1.8 ± 0.3 mV). A similar rank of order was observed in neural mediated inhibitory mechanical responses including electrical field stimulation-mediated responses and neural tone. ADPβs concentration-response curve was shifted to the left in the distal colon. In contrast, NaNP responses did not differ between regions. Cholinergic neurotransmission elicited contractions of a similar amplitude throughout the colon. CONCLUSION An inverse gradient of purinergic and nitrergic neurotransmission exists through the mouse colon. The proximal and mid colon have a predominant nitrergic neurotransmission probably due to the fact that their storage function requires sustained relaxations. The distal colon, in contrast, has mainly purinergic neurotransmission responsible for the phasic relaxations needed to propel dehydrated faeces.
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Affiliation(s)
- N. Mañé
- Department of Cell Biology, Physiology and Immunology and Neuroscience Institute; Universitat Autònoma de Barcelona; Barcelona Spain
| | - R. Viais
- Center for Drug Discovery and Innovative Medicines (MedInUP); Instituto de Ciências Biomédicas Abel Salazar da Universidade do Porto (ICBAS-UP); Porto Portugal
| | - M. Martínez-Cutillas
- Department of Cell Biology, Physiology and Immunology and Neuroscience Institute; Universitat Autònoma de Barcelona; Barcelona Spain
| | - D. Gallego
- Department of Cell Biology, Physiology and Immunology and Neuroscience Institute; Universitat Autònoma de Barcelona; Barcelona Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd); Instituto de Salud Carlos III; Barcelona Spain
| | - P. Correia-de-Sá
- Center for Drug Discovery and Innovative Medicines (MedInUP); Instituto de Ciências Biomédicas Abel Salazar da Universidade do Porto (ICBAS-UP); Porto Portugal
| | - M. Jiménez
- Department of Cell Biology, Physiology and Immunology and Neuroscience Institute; Universitat Autònoma de Barcelona; Barcelona Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd); Instituto de Salud Carlos III; Barcelona Spain
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19
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Mota F, Gane P, Hampden-Smith K, Allerston CK, Garthwaite J, Selwood DL. A new small molecule inhibitor of soluble guanylate cyclase. Bioorg Med Chem 2015; 23:5303-10. [PMID: 26264842 PMCID: PMC4558462 DOI: 10.1016/j.bmc.2015.07.074] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Revised: 07/29/2015] [Accepted: 07/30/2015] [Indexed: 12/22/2022]
Abstract
Soluble guanylate cyclase (sGC) is a haem containing enzyme that regulates cardiovascular homeostasis and multiple mechanisms in the central and peripheral nervous system. Commonly used inhibitors of sGC activity act through oxidation of the haem moiety, however they also bind haemoglobin and this limits their bioavailability for in vivo studies. We have discovered a new class of small molecule inhibitors of sGC and have characterised a compound designated D12 (compound 10) which binds to the catalytic domain of the enzyme with a KD of 11 μM in a SPR assay.
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Affiliation(s)
- Filipa Mota
- The Wolfson Institute for Biomedical Research, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Paul Gane
- The Wolfson Institute for Biomedical Research, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Kathryn Hampden-Smith
- The Wolfson Institute for Biomedical Research, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Charles K Allerston
- Structural Genomics Consortium, University of Oxford, Roosevelt Drive, Oxford OX3 7DQ, United Kingdom
| | - John Garthwaite
- The Wolfson Institute for Biomedical Research, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - David L Selwood
- The Wolfson Institute for Biomedical Research, University College London, Gower Street, London WC1E 6BT, United Kingdom.
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20
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Inserte J, Garcia-Dorado D. The cGMP/PKG pathway as a common mediator of cardioprotection: translatability and mechanism. Br J Pharmacol 2015; 172:1996-2009. [PMID: 25297462 DOI: 10.1111/bph.12959] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Revised: 09/16/2014] [Accepted: 09/26/2014] [Indexed: 12/24/2022] Open
Abstract
Cardiomyocyte cell death occurring during myocardial reperfusion (reperfusion injury) contributes to final infarct size after transient coronary occlusion. Different interrelated mechanisms of reperfusion injury have been identified, including alterations in cytosolic Ca(2+) handling, sarcoplasmic reticulum-mediated Ca(2+) oscillations and hypercontracture, proteolysis secondary to calpain activation and mitochondrial permeability transition. All these mechanisms occur during the initial minutes of reperfusion and are inhibited by intracellular acidosis. The cGMP/PKG pathway modulates the rate of recovery of intracellular pH, but has also direct effect on Ca(2+) oscillations and mitochondrial permeability transition. The cGMP/PKG pathway is depressed in cardiomyocytes by ischaemia/reperfusion and preserved by ischaemic postconditioning, which importantly contributes to postconditioning protection. The present article reviews the mechanisms and consequences of the effect of ischaemic postconditioning on the cGMP/PKG pathway, the different pharmacological strategies aimed to stimulate it during myocardial reperfusion and the evidence, limitations and promise of translation of these strategies to the clinical practice. Overall, the preclinical and clinical evidence suggests that modulation of the cGMP/PKG pathway may be a therapeutic target in the context of myocardial infarction.
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Affiliation(s)
- Javier Inserte
- Cardiology Department, Vall d'Hebron University Hospital and Research Institute, Universitat Autònoma de Barcelona, Barcelona, Spain
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21
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Mañé N, Gil V, Martínez-Cutillas M, Clavé P, Gallego D, Jiménez M. Differential functional role of purinergic and nitrergic inhibitory cotransmitters in human colonic relaxation. Acta Physiol (Oxf) 2014; 212:293-305. [PMID: 25327170 DOI: 10.1111/apha.12408] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 09/23/2014] [Accepted: 10/14/2014] [Indexed: 12/18/2022]
Abstract
AIM ATP and nitric oxide (NO) are released from enteric inhibitory motor neurones and are responsible for colonic smooth muscle relaxation. However, how frequency of neural stimulation affects this cotransmission process and the post-junctional responses has not been systematically characterized in the human colon. METHODS The dynamics of inhibitory cotransmission were studied using different protocols of electrical field stimulation (EFS) to characterize the inhibitory junction potentials (IJP) and the corresponding relaxation in colonic strips obtained from 36 patients. RESULTS Single pulses elicited a fast IJP (IJPf(MAX) = -27.6 ± 1.6 mV), sensitive to the P2Y1 antagonist MRS2500 1 μm, that ran down with frequency increase leaving a residual hyperpolarization at high frequencies (IJPf∞ = -3.7 ± 0.6 mV). Accordingly, low frequencies of EFS caused purinergic transient relaxations that cannot be maintained at high frequencies. Addition of the P2Y1 agonist MRS2365 10 μm during the purinergic rundown did not cause any hyperpolarization. Protein kinase C (PKC), a putative P2Y1 desensitizator, was able to reduce the amplitude of the IJPf when activated, but the rundown was not modified by PKC inhibitors. Frequencies higher than 0.60 ± 0.15 Hz were needed to evoke a sustained nitrergic hyperpolarization that progressively increased reaching IJPs∞ = -13 ± 0.4 mV at high frequencies and leading to a sustained inhibition of spontaneous motility. CONCLUSION Changes in frequency of stimulation possibly mimicking neuronal firing will post-junctionally determine purinergic vs. nitrergic responses underlying different functional roles. NO will be responsible for sustained relaxations needed in physiological processes such as storage, while purinergic neurotransmission evoking sharp transient relaxations will be dominant in processes such as propulsion.
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Affiliation(s)
- N. Mañé
- Department of Cell Biology, Physiology and Immunology and Neuroscience Institute; Universitat Autònoma de Barcelona; Barcelona Spain
| | - V. Gil
- Department of Cell Biology, Physiology and Immunology and Neuroscience Institute; Universitat Autònoma de Barcelona; Barcelona Spain
| | - M. Martínez-Cutillas
- Department of Cell Biology, Physiology and Immunology and Neuroscience Institute; Universitat Autònoma de Barcelona; Barcelona Spain
| | - P. Clavé
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd); Instituto de Salud Carlos III; Barcelona Spain
| | - D. Gallego
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd); Instituto de Salud Carlos III; Barcelona Spain
| | - M. Jiménez
- Department of Cell Biology, Physiology and Immunology and Neuroscience Institute; Universitat Autònoma de Barcelona; Barcelona Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd); Instituto de Salud Carlos III; Barcelona Spain
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22
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Cobine CA, Sotherton AG, Peri LE, Sanders KM, Ward SM, Keef KD. Nitrergic neuromuscular transmission in the mouse internal anal sphincter is accomplished by multiple pathways and postjunctional effector cells. Am J Physiol Gastrointest Liver Physiol 2014; 307:G1057-72. [PMID: 25301187 PMCID: PMC4254957 DOI: 10.1152/ajpgi.00331.2014] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The effector cells and second messengers participating in nitrergic neuromuscular transmission (NMT) were investigated in the mouse internal anal sphincter (IAS). Protein expression of guanylate cyclase (GCα, GCβ) and cyclic GMP-dependent protein kinase I (cGKI) were examined in cryostat sections with dual-labeling immunohistochemical techniques in PDGFRα(+) cells, interstitial cells of Cajal (ICC), and smooth muscle cells (SMC). Gene expression levels were determined with quantitative PCR of dispersed cells from Pdgfrα(egfp/+), Kit(copGFP/+), and smMHC(Cre-egfp) mice sorted with FACS. The relative gene and protein expression levels of GCα and GCβ were PDGFRα(+) cells > ICC ≫ SMC. In contrast, cGKI gene expression sequence was SMC = ICC > PDGFRα(+) cells whereas cGKI protein expression sequence was neurons > SMC ≫ ICC = PDGFRα(+) cells. The functional role of cGKI was investigated in cGKI(-/-) mice. Relaxation with 8-bromo (8-Br)-cGMP was greatly reduced in cGKI(-/-) mice whereas responses to sodium nitroprusside (SNP) were partially reduced and forskolin responses were unchanged. A nitrergic relaxation occurred with nerve stimulation (NS, 5 Hz, 60 s) in cGKI(+/+) and cGKI(-/-) mice although there was a small reduction in the cGKI(-/-) mouse. N(ω)-nitro-l-arginine (l-NNA) abolished responses during the first 20-30 s of NS in both animals. The GC inhibitor ODQ greatly reduced or abolished SNP and nitrergic NS responses in both animals. These data confirm an essential role for GC in NO-induced relaxation in the IAS. However, the expression of GC and cGKI by all three cell types suggests that each may participate in coordinating muscular responses to NO. The persistence of nitrergic NMT in the cGKI(-/-) mouse suggests the presence of a significant GC-dependent, cGKI-independent pathway.
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Affiliation(s)
- C. A. Cobine
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada
| | - A. G. Sotherton
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada
| | - L. E. Peri
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada
| | - K. M. Sanders
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada
| | - S. M. Ward
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada
| | - K. D. Keef
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada
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Lies B, Groneberg D, Friebe A. Toward a better understanding of gastrointestinal nitrergic neuromuscular transmission. Neurogastroenterol Motil 2014; 26:901-12. [PMID: 24827638 DOI: 10.1111/nmo.12367] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Accepted: 04/21/2014] [Indexed: 12/30/2022]
Abstract
BACKGROUND Nitric oxide (NO) is an important inhibitory neurotransmitter in the gastrointestinal (GI) tract. The majority of nitrergic effects are transduced by NO-sensitive guanylyl cyclase (NO-GC) as the receptor for NO, and, thus, mediated by cGMP-dependent mechanisms. Work carried out during the past years has demonstrated NO to be largely involved in GI smooth muscle relaxation and motility. However, detailed investigation of nitrergic signaling has turned out to be complicated as NO-GC was identified in several different GI cell types such as smooth muscle cells, interstitial cells of Cajal and fibroblast-like cells. With regards to nitrergic neurotransmission, special focus has been placed on the role of interstitial cells of Cajal using mutant mice with reduced populations of ICC. Recently, global and cell-specific knockout mice for enzymes participating in nitrergic signaling have been generated providing a suitable approach to further examine the role of NO-mediated signaling in GI smooth muscle. PURPOSE This review discusses the current knowledge on nitrergic mechanisms in gastrointestinal neuromuscular transmission with a focus on genetic models and outlines possible further investigations to gain better understanding on NO-mediated effects in the GI tract.
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Affiliation(s)
- B Lies
- Physiologisches Institut I, Universität Würzburg, Würzburg, Germany
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The Relative Role of Soluble Guanylyl Cylase Dependent and Independent Pathways in Nitric Oxide Inhibition of Platelet Aggregation Under Flow. Cell Mol Bioeng 2014. [DOI: 10.1007/s12195-014-0331-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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25
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Dynamics of inhibitory co-transmission, membrane potential and pacemaker activity determine neuromyogenic function in the rat colon. Pflugers Arch 2014; 466:2305-21. [DOI: 10.1007/s00424-014-1500-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Revised: 02/26/2014] [Accepted: 03/10/2014] [Indexed: 01/26/2023]
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