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Frigolet ME, Thomas G, Beard K, Lu H, Liu L, Fantus IG. The bradykinin-cGMP-PKG pathway augments insulin sensitivity via upregulation of MAPK phosphatase-5 and inhibition of JNK. Am J Physiol Endocrinol Metab 2017; 313:E321-E334. [PMID: 28679626 DOI: 10.1152/ajpendo.00298.2016] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Revised: 05/25/2017] [Accepted: 05/30/2017] [Indexed: 01/13/2023]
Abstract
Bradykinin (BK) promotes insulin sensitivity and glucose uptake in adipocytes and other cell types. We demonstrated that in rat adipocytes BK enhances insulin-stimulated glucose transport via endothelial nitric oxide synthase, nitric oxide (NO) generation, and decreased activity of the mitogen-activated protein kinase (MAPK) JNK (c-Jun NH2-terminal kinase). In endothelial cells, NO increases soluble guanylate cyclase (sGC) activity, which, in turn, activates protein kinase G (PKG) by increasing cGMP levels. In this study, we investigated whether BK acts via the sGC-cGMP-PKG pathway to inhibit the negative effects of JNK on insulin signaling and glucose uptake in rat adipocytes. BK augmented cGMP concentrations. The BK-induced enhancement of insulin-stimulated glucose uptake was mimicked by the sGC activator YC-1 and a cell-permeable cGMP analog, CPT-cGMP, and inhibited by the sGC inhibitor ODQ and the PKG inhibitor KT 5823. Transfection of dominant-negative PKG reduced the BK augmentation of insulin-induced Akt phosphorylation. The activation of JNK and ERK1/2 by insulin was attenuated by BK, which was mediated by the sGC-cGMP-PKG pathway. Whereas insulin-stimulated phosphorylation of upstream activators of JNK and ERK, i.e., MKK4 and MEK1/2, was unaffected, BK augmented insulin-mediated induction of MKP-5 mRNA and protein levels. Furthermore, zaprinast, a phosphodiesterase inhibitor, enhanced cGMP and MKP-5 and prolonged the action of BK. These data indicate that BK enhances insulin action by inhibition of negative feedback by JNK and ERK via upregulation of MKP-5, mediated by the sGC-cGMP-PKG signaling pathway.
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Affiliation(s)
- María E Frigolet
- Toronto General Research Institute, University Health Network, Toronto, Ontario, Canada
- Banting and Best Diabetes Centre, Toronto, Ontario, Canada; and
| | - Garry Thomas
- Department of Medicine, Mount Sinai Hospital, Toronto, Ontario, Canada
- Banting and Best Diabetes Centre, Toronto, Ontario, Canada; and
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Kristin Beard
- Department of Medicine, Mount Sinai Hospital, Toronto, Ontario, Canada
- Banting and Best Diabetes Centre, Toronto, Ontario, Canada; and
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Huogen Lu
- Toronto General Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Lijiang Liu
- Toronto General Research Institute, University Health Network, Toronto, Ontario, Canada
| | - I George Fantus
- Department of Medicine, Mount Sinai Hospital, Toronto, Ontario, Canada;
- Toronto General Research Institute, University Health Network, Toronto, Ontario, Canada
- Banting and Best Diabetes Centre, Toronto, Ontario, Canada; and
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
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Geenen IL, Kolk FF, Molin DG, Wagenaar A, Compeer MG, Tordoir JH, Schurink GW, De Mey JG, Post MJ. Nitric Oxide Resistance Reduces Arteriovenous Fistula Maturation in Chronic Kidney Disease in Rats. PLoS One 2016; 11:e0146212. [PMID: 26727368 PMCID: PMC4699647 DOI: 10.1371/journal.pone.0146212] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Accepted: 12/15/2015] [Indexed: 12/20/2022] Open
Abstract
Background Autologous arteriovenous (AV) fistulas are the first choice for vascular access but have a high risk of non-maturation due to insufficient vessel adaptation, a process dependent on nitric oxide (NO)-signaling. Chronic kidney disease (CKD) is associated with oxidative stress that can disturb NO-signaling. Here, we evaluated the influence of CKD on AV fistula maturation and NO-signaling. Methods CKD was established in rats by a 5/6th nephrectomy and after 6 weeks, an AV fistula was created between the carotid artery and jugular vein, which was followed up at 3 weeks with ultrasound and flow assessments. Vessel wall histology was assessed afterwards and vasoreactivity of carotid arteries was studied in a wire myograph. The soluble guanylate cyclase (sGC) activator BAY 60–2770 was administered daily to CKD animals for 3 weeks to enhance fistula maturation. Results CKD animals showed lower flow rates, smaller fistula diameters and increased oxidative stress levels in the vessel wall. Endothelium-dependent relaxation was comparable but vasorelaxation after sodium nitroprusside was diminished in CKD vessels, indicating NO resistance of the NO-receptor sGC. This was confirmed by stimulation with BAY 60–2770 resulting in increased vasorelaxation in CKD vessels. Oral administration of BAY 60–2770 to CKD animals induced larger fistula diameters, however; flow was not significantly different from vehicle-treated CKD animals. Conclusions CKD induces oxidative stress resulting in NO resistance that can hamper AV fistula maturation. sGC activators like BAY 60–2770 could offer therapeutic potential to increase AV fistula maturation.
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Affiliation(s)
- Irma L. Geenen
- Department of Physiology, Cardiovascular Research Institute Maastricht, Maastricht University Medical Center, Maastricht, The Netherlands
- Department of General Surgery, Cardiovascular Research Institute Maastricht, Maastricht University Medical Center, Maastricht, The Netherlands
- * E-mail:
| | - Felix F. Kolk
- Department of Physiology, Cardiovascular Research Institute Maastricht, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Daniel G. Molin
- Department of Physiology, Cardiovascular Research Institute Maastricht, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Allard Wagenaar
- Department of Physiology, Cardiovascular Research Institute Maastricht, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Mathijs G. Compeer
- Department of Pharmacology, Cardiovascular Research Institute Maastricht, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Jan H. Tordoir
- Department of General Surgery, Cardiovascular Research Institute Maastricht, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Geert W. Schurink
- Department of General Surgery, Cardiovascular Research Institute Maastricht, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Jo G. De Mey
- Department of Pharmacology, Cardiovascular Research Institute Maastricht, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Mark J. Post
- Department of Physiology, Cardiovascular Research Institute Maastricht, Maastricht University Medical Center, Maastricht, The Netherlands
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Gheorghiade M, Greene SJ, Butler J, Filippatos G, Lam CSP, Maggioni AP, Ponikowski P, Shah SJ, Solomon SD, Kraigher-Krainer E, Samano ET, Müller K, Roessig L, Pieske B. Effect of Vericiguat, a Soluble Guanylate Cyclase Stimulator, on Natriuretic Peptide Levels in Patients With Worsening Chronic Heart Failure and Reduced Ejection Fraction: The SOCRATES-REDUCED Randomized Trial. JAMA 2015; 314:2251-62. [PMID: 26547357 DOI: 10.1001/jama.2015.15734] [Citation(s) in RCA: 255] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
IMPORTANCE Worsening chronic heart failure (HF) is a major public health problem. OBJECTIVE To determine the optimal dose and tolerability of vericiguat, a soluble guanylate cyclase stimulator, in patients with worsening chronic HF and reduced left ventricular ejection fraction (LVEF). DESIGN, SETTING, AND PARTICIPANTS Dose-finding phase 2 study that randomized 456 patients across Europe, North America, and Asia between November 2013 and January 2015, with follow-up ending June 2015. Patients were clinically stable with LVEF less than 45% within 4 weeks of a worsening chronic HF event, defined as worsening signs and symptoms of congestion and elevated natriuretic peptide level requiring hospitalization or outpatient intravenous diuretic. INTERVENTIONS Placebo (n = 92) or 1 of 4 daily target doses of oral vericiguat (1.25 mg [n = 91], 2.5 mg [n = 91], 5 mg [n = 91], 10 mg [n = 91]) for 12 weeks. MAIN OUTCOMES AND MEASURES The primary end point was change from baseline to week 12 in log-transformed level of N-terminal pro-B-type natriuretic peptide (NT-proBNP). The primary analysis specified pooled comparison of the 3 highest-dose vericiguat groups with placebo, and secondary analysis evaluated a dose-response relationship with vericiguat and the primary end point. RESULTS Overall, 351 patients (77.0%) completed treatment with the study drug with valid 12-week NT-proBNP levels and no major protocol deviation and were eligible for primary end point evaluation. In primary analysis, change in log-transformed NT-proBNP levels from baseline to week 12 was not significantly different between the pooled vericiguat group (log-transformed: baseline, 7.969; 12 weeks, 7.567; difference, -0.402; geometric means: baseline, 2890 pg/mL; 12 weeks, 1932 pg/mL) and placebo (log-transformed: baseline, 8.283; 12 weeks, 8.002; difference, -0.280; geometric means: baseline, 3955 pg/mL; 12 weeks, 2988 pg/mL) (difference of means, -0.122; 90% CI, -0.32 to 0.07; ratio of geometric means, 0.885, 90% CI, 0.73-1.08; P = .15). The exploratory secondary analysis suggested a dose-response relationship whereby higher vericiguat doses were associated with greater reductions in NT-proBNP level (P < .02). Rates of any adverse event were 77.2% and 71.4% among the placebo and 10-mg vericiguat groups, respectively. CONCLUSIONS AND RELEVANCE Among patients with worsening chronic HF and reduced LVEF, compared with placebo, vericiguat did not have a statistically significant effect on change in NT-proBNP level at 12 weeks but was well-tolerated. Further clinical trials of vericiguat based on the dose-response relationship in this study are needed to determine the potential role of this drug for patients with worsening chronic HF. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT01951625.
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Affiliation(s)
- Mihai Gheorghiade
- Center for Cardiovascular Innovation, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Stephen J Greene
- Division of Cardiology, Duke University Medical Center, Durham, North Carolina
| | - Javed Butler
- Division of Cardiology, Stony Brook University, Stony Brook, New York
| | - Gerasimos Filippatos
- Heart Failure Unit, Department of Cardiology, Athens University Hospital Attikon, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece
| | - Carolyn S P Lam
- Department of Cardiology, National Heart Centre Singapore and Duke, National University of Singapore, Singapore
| | - Aldo P Maggioni
- Associazione Nazionale Medici Cardiologi Ospedalieri Research Center, Florence, Italy
| | - Piotr Ponikowski
- Department of Heart Diseases, Medical University, Military Hospital, Wroclaw, Poland
| | - Sanjiv J Shah
- Division of Cardiology, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Scott D Solomon
- Cardiovascular Division, Brigham and Women's Hospital, Boston, Massachusetts
| | - Elisabeth Kraigher-Krainer
- Department of Internal Medicine and Cardiology, Charité University Medicine Berlin-Campus Virchow Klinikum, Berlin, Germany
| | | | | | | | - Burkert Pieske
- Department of Internal Medicine and Cardiology, Charité University Medicine Berlin-Campus Virchow Klinikum, Berlin, Germany13Department of Internal Medicine and Cardiology, German Heart Center Berlin, Berlin, Germany
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Affiliation(s)
| | - Jason T Connor
- Berry Consultants LLC, Austin, Texas2University of Central Florida College of Medicine, Orlando
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Durmus N, Bagcivan I, Ozdemir E, Altun A, Gursoy S. Soluble guanylyl cyclase activators increase the expression of tolerance to morphine analgesic effect. ACTA ACUST UNITED AC 2014; 115:334-9. [PMID: 25023422 DOI: 10.4149/bll_2014_066] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVES It is aimed to investigate the effects of guanylyl cyclase activation and inhibition on acute morphine antinociception and the development of tolerance to its effect. BACKGROUND Nitric oxide-soluble guanylyl cyclase signal transduction cascade suggested to play an important role in the development of tolerance to antinociceptive effects of morphine. METHODS Nociception was evaluated by tail flick and hot plate tests in male Wistar rats. The analgesic effects of intraperitoneal protoporphyrin IX (PPIX; an activator of soluble guanylyl cyclase), 3-morpholinosydnonimine hydrochloride (SIN-1; NO donor and activator of guanylyl cyclase), S-Nitroso-N-acetylpenicillamine (SNAP; an activator of guanylyl cyclase), 3,3-Bis (amino ethyl)-1-hydroxy-2-oxo-1-triazene (NOC-18; NO donor activating guanylyl cyclase) and 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ; an inhibitor of guanylyl cyclase) alone or in combination with subcutaneous morphine injection were evaluated. Their effects on morphine tolerance development were evaluated by giving these agents 20 minutes prior to twice daily morphine injection during tolerance development for 5 days. On day 6, the expression of morphine tolerance was determined. RESULTS PPIX, SIN-1, SNAP and NOC-18 significantly increased expression of morphine tolerance while ODQ decreased. CONCLUSION These data suggested that sGC activators have a significant role in tolerance to the analgesic effect of morphine (Tab. 1, Fig. 4, Ref. 29).
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Abstract
Riociguat (Adempas(®)), an oral first-in-class soluble guanylate cyclase (sGC) stimulator, is under global development by Bayer Healthcare Pharmaceuticals Inc. for the treatment of adult patients with inoperable or chronic/persistent chronic thromboembolic pulmonary hypertension (CTEPH) and for the treatment of adult patients with pulmonary arterial hypertension (PAH). The drug directly stimulates sGC in a nitric oxide independent manner, thereby increasing the sensitivity of sGC to nitric oxide, leading to increased cyclic guanosine monophosphate generation (a key signalling molecule involved in regulating vascular tone, proliferation, fibrosis and inflammation). Riociguat is the world's first approved pharmacotherapy for CTEPH, with its first global approval in this indication occurring in Canada. It has subsequently been approved in the USA for the treatment of patients with CTEPH and also received its first global approval in patients with PAH in the USA. It is undergoing regulatory review for these indications in Europe and for use in patients with CTEPH in Japan. This article summarizes the milestones in the development of riociguat, leading to its first global approvals in patients with CTEPH and PAH.
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Affiliation(s)
- Daniel Conole
- Adis R&D Insight, 41 Centorian Drive, Private Bag 65901, Mairangi Bay, North Shore, 0754, Auckland, New Zealand,
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Lundgren J, Kylhammar D, Hedelin P, Rådegran G. sGC stimulation totally reverses hypoxia-induced pulmonary vasoconstriction alone and combined with dual endothelin-receptor blockade in a porcine model. Acta Physiol (Oxf) 2012; 206:178-94. [PMID: 22682645 DOI: 10.1111/j.1748-1716.2012.02445.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2011] [Revised: 12/21/2011] [Accepted: 04/12/2012] [Indexed: 11/30/2022]
Abstract
AIM Stimulation of soluble guanylate cyclase (sGC) with BAY 41-8543 was hypothesized to attenuate acute hypoxic pulmonary vasoconstriction alone and combined with dual endothelin (ET)-receptor antagonist tezosentan. METHODS Measurements were taken in 18 anaesthetized pigs with a mean ± SEM weight of 31.1 ± 0.4 kg, in normoxia (FiO(2)~0.21) and hypoxia (FiO(2)~0.10) without (control protocol, n = 6), and with right atrial infusion of BAY 41-8543 at 1, 3, 6, 9 and 12 μg min(-1) per kg (protocol 2, n = 6) or tezosentan at 5 mg kg(-1) followed by BAY 41-8543 at 1, 3 and 6 μg min(-1) per kg (protocol 3, n = 6). RESULTS Hypoxia (n = 18) increased (P < 0.001) mean pulmonary artery pressure (MPAP) and pulmonary vascular resistance (PVR) by 14.2 ± 0.6 mmHg and 2.8 ± 0.3 WU respectively. During sustained hypoxia without treatment, MPAP and PVR remained stable. BAY 41-8543 (n = 6) dose-dependently decreased (P < 0.001) MPAP and PVR by 15.0 ± 1.2 mmHg and 4.7 ± 0.7 WU respectively. Tezosentan (n = 6) decreased (P < 0.001) MPAP and PVR by 11.8 ± 1.2 mmHg and 2.0 ± 0.2 WU, respectively, whereafter BAY 41-8543 (n = 6) further decreased (P < 0.001) MPAP and PVR by 6.6 ± 0.9 mmHg and 1.9 ± 0.4 WU respectively. Both BAY 41-8543 and tezosentan decreased (P < 0.001) systemic arterial pressure and systemic vascular resistance. Blood-O(2) consumption remained unaltered (P = ns) during all interventions. CONCLUSION BAY 41-8543 totally reverses the effects of acute hypoxia-induced pulmonary vasoconstriction, and enhances the attenuating effects of tezosentan, without affecting oxygenation. Thus, sGC stimulation, alone or combined with dual ET-receptor blockade, could offer a means to treat pulmonary hypertension related to hypoxia and potentially other causes.
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Affiliation(s)
- J Lundgren
- The Öresund Cardiovascular Research Collaboration, The Clinic for Heart Failure and Valvular Disease, Skåne University Hospital, Lund, Sweden
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Willoughby SR, Rajendran S, Chan WP, Procter N, Leslie S, Liberts EA, Heresztyn T, Chirkov YY, Horowitz JD. Ramipril sensitizes platelets to nitric oxide: implications for therapy in high-risk patients. J Am Coll Cardiol 2012; 60:887-94. [PMID: 22682555 DOI: 10.1016/j.jacc.2012.01.066] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2011] [Revised: 01/20/2012] [Accepted: 01/23/2012] [Indexed: 01/25/2023]
Abstract
OBJECTIVES Using 2 sequential studies in HOPE (Heart Outcomes Prevention Evaluation) study-type patients, the aims of this study were: 1) to test the hypothesis that ramipril improves platelet nitric oxide (NO) responsiveness: and 2) to explore biochemical and physiological effects of ramipril in a cohort selected on the basis of platelet NO resistance. BACKGROUND Ramipril prevents cardiovascular events, but the bases for these effects remain uncertain. NO resistance at both the platelet and vascular levels is present in a substantial proportion of patients with diabetes or ischemic heart disease and is an independent risk factor for cardiovascular events. METHODS Study 1 was a double-blind, randomized comparison of ramipril (10 mg) with placebo in a cohort of patients (n = 119) with ischemic heart disease or diabetes plus additional coronary risk factor(s), in which effects on platelet responsiveness to NO were compared. Study 2 was a subsequent short-term evaluation of the effects of ramipril in a cohort of subjects (n = 19) with impaired platelet NO responsiveness in whom additional mechanistic data were sought. RESULTS In study 1, ramipril therapy increased platelet responsiveness to NO relative to the extent of aggregation (p < 0.001), but this effect occurred primarily in patients with severely impaired baseline NO responsiveness (n = 41). In study 2, ramipril also improved platelet NO responsiveness (p < 0.01), and this improvement was correlated directly with increased NO-stimulated platelet generation of cyclic guanosine monophosphate (p < 0.02) but not with changes in plasma thrombospondin-1 levels. CONCLUSIONS Ramipril ameliorates platelet NO resistance in HOPE study-type patients, with associated increases in soluble guanylate cyclase responsiveness to NO. This effect is likely to contribute to treatment benefit and define patients in whom ramipril therapy is particularly effective.
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Affiliation(s)
- Scott R Willoughby
- Cardiology Unit, The Basil Hetzel Institute, The Queen Elizabeth Hospital, Discipline of Medicine, University of Adelaide, Adelaide, Australia
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Shpakov AO, Derkach KV, Uspenskaia ZI. [Effect of natural amino acids and sugars on cyclase activities in infusoria Tetrahymena pyriformis and Dileptus anser]. Zh Evol Biokhim Fiziol 2011; 47:128-135. [PMID: 21598697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Natural amino acids and sugars in intracellular eukaryotes are known to regulate adenylyl cyclase (AC) and guanylyl cyclase (GC) systems that control the most important cell processes. The goal of the present work consisted in study of effects of natural amino acids and sugars and some of their derivatives on AC and GC activities of infusoria Tetrahymena pyriformis and Dileptus anser. Methionine, arginine, lysine, and tryptamine stimulated basic AC activity of T. pyriformis, whereas alanine, thyrosine, and cysteine decreased it. Methionine, glycine, alanine, thyrosine, arginine, and to the lesser degree tryptamine and histidine stimulated AC of D. anser. The GC activity of T. pyriformis are increased in the presence of tryptamine, tryptophane, histidine, arginine, and lysine, whereas glycine and aspartic acid, on the contrary, decreased it. Tryptamine, tryptophan, leucine, glutamic acid, serine, histidine, and alanine stimulated the GC activity of D. anser. Glucose, fructose, and sucrose stimulated the basal AC activity of both infusorians and GC of T. pyriformis, with glucose and sucrose increasing AC of T. pyriformis twice, while that of D. anser 4.5 times. Lactose stimulated AC and GC of T. pyriformis and was inefficient with respect to the D. anser cyclases, whereas mannose and galactose did not affect the enzyme activities in both infusorians. The study of the chemotactic response of infusorians to amino acids and sugars indicates that involved in realization of this response can be signaling pathways both dependent on and independent of cyclic nucleotides. Thus, it has been established for the first time that several amino acids and sugars affect functional activity of enzymes with cyclase activity of the infusorians T. pyriformis and D. anser. This confirms the hypothesis that at early stages of evolution the large spectrum of comparatively simple natural molecules has a hormone-like action.
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Molecule of the month. Linaclotide acetate. Drug News Perspect 2010; 23:515. [PMID: 21031167 DOI: 10.1358/dnp.2010.23.8.1538348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
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Abstract
In this review we investigate the role of particulate and soluble guanylate cyclase (pGC and sGC, respectively) pathways in heart failure, and several novel drugs that modify guanylate cyclase. Nesiritide and ularitide/urodilatin are natriuretic peptides with vasodilating, natriuretic and diuretic effects, acting on pGC, whilst cinaciguat (BAY 58-2667) is a novel sGC activator. Cinaciguat has a promising and novel mode of action because it can stimulate cyclic guanosine-3',5'-monophosphate synthesis by targeting sGC in its nitric oxide-insensitive, oxidised ferric (Fe(3+)) or haem-free state. Thus, cinaciguat may also be effective under oxidative stress conditions resulting in oxidised or haem-free sGC refractory to traditional organic nitrate therapies. Preliminary studies of cinaciguat in patients with acute decompensated heart failure show substantial improvements in haemodynamics and symptoms, whilst maintaining renal function.
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Abstract
Oxidative stress, a risk factor for several cardiovascular disorders, interferes with the NO/sGC/cGMP signalling pathway through scavenging of NO and formation of the strong intermediate oxidant, peroxynitrite. Under these conditions, endothelial and vascular dysfunction develops, culminating in different cardio-renal and pulmonary-vascular diseases. Substituting NO with organic nitrates that release NO (NO donors) has been an important principle in cardiovascular therapy for more than a century. However, the development of nitrate tolerance limits their continuous clinical application and, under oxidative stress and increased formation of peroxynitrite foils the desired therapeutic effect. To overcome these obstacles of nitrate therapy, direct NO- and haem-independent sGC activators have been developed, such as BAY 58-2667 (cinaciguat) and HMR1766 (ataciguat), showing unique biochemical and pharmacological properties. Both compounds are capable of selectively activating the oxidized/haem-free enzyme via binding to the enzyme's haem pocket, causing pronounced vasodilatation. The potential importance of these new drugs resides in the fact that they selectively target a modified state of sGC that is prevalent under disease conditions as shown in several animal models and human disease. Activators of sGC may be beneficial in the treatment of a range of diseases including systemic and pulmonary hypertension (PH), heart failure, atherosclerosis, peripheral arterial occlusive disease (PAOD), thrombosis and renal fibrosis. The sGC activator HMR1766 is currently in clinical development as an oral therapy for patients with PAOD. The sGC activator BAY 58-2667 has demonstrated efficacy in a proof-of-concept study in patients with acute decompensated heart failure (ADHF), reducing pre- and afterload and increasing cardiac output from baseline. A phase IIb clinical study for the indication of ADHF is currently underway.
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Affiliation(s)
- Harald H H W Schmidt
- Department of Pharmacology and Centre for Vascular Health, Monash University, Clayton, VIC, 3800, Australia
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Abstract
The nitric oxide (NO) signalling pathway is altered in cardiovascular diseases, including systemic and pulmonary hypertension, stroke, and atherosclerosis. The vasodilatory properties of NO have been exploited for over a century in cardiovascular disease, but NO donor drugs and inhaled NO are associated with significant shortcomings, including resistance to NO in some disease states, the development of tolerance during long-term treatment, and non-specific effects such as post-translational modification of proteins. The development of pharmacological agents capable of directly stimulating the NO receptor, soluble guanylate cyclase (sGC), is therefore highly desirable. The benzylindazole compound YC-1 was the first sGC stimulator to be identified; this compound formed a lead structure for the development of optimized sGC stimulators with improved potency and specificity for sGC, including CFM-1571, BAY 41-2272, BAY 41-8543, and BAY 63-2521. In contrast to the NO- and haem-independent sGC activators such as BAY 58-2667, these compounds stimulate sGC activity independent of NO and also act in synergy with NO to produce anti-aggregatory, anti-proliferative, and vasodilatory effects. Recently, aryl-acrylamide compounds were identified independent of YC-1 as sGC stimulators; although structurally dissimilar to YC-1, they have a similar mode of action and promote smooth muscle relaxation. Pharmacological stimulators of sGC may be beneficial in the treatment of a range of diseases, including systemic and pulmonary hypertension, heart failure, atherosclerosis, erectile dysfunction, and renal fibrosis. An sGC stimulator, BAY 63-2521, is currently in clinical development as an oral therapy for patients with pulmonary hypertension. It has demonstrated efficacy in a proof-of-concept study, reducing pulmonary vascular resistance and increasing cardiac output from baseline. A full, phase 2 trial of BAY 63-2521 in pulmonary hypertension is underway.
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Affiliation(s)
- Johannes-Peter Stasch
- Bayer Schering Pharma AG, Cardiology Research, Pharma Research Center, Wuppertal, 42096, Germany.
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Abstract
Heart failure (HF) is a common disease that continues to be associated with high morbidity and mortality warranting novel therapeutic strategies. Cyclic guanosine monophosphate (cGMP) is the second messenger of several important signaling pathways based on distinct guanylate cyclases (GCs) in the cardiovascular system. Both the nitric oxide/soluble GC (NO/sGC) as well as the natriuretic peptide/GC-A (NP/GC-A) systems are disordered in HF, providing a rationale for their therapeutic augmentation. Soluble GC activation with conventional nitrovasodilators has been used for more than a century but is associated with cGMP-independent actions and the development of tolerance, actions which novel NO-independent sGC activators now in clinical development lack. Activation of GC-A by administration of naturally occurring or designer natriuretic peptides is an emerging field, as is the inhibition of enzymes that degrade endogenous NPs. Finally, inhibition of cGMP-degrading phosphodiesterases, particularly phosphodiesterase 5 provides an additional strategy to augment cGMP-signaling.
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Affiliation(s)
- Guido Boerrigter
- Cardiorenal Research Laboratory, Division of Cardiovascular Diseases, Mayo Heart and Lung Research Center, Mayo Clinic and Mayo Clinic College of Medicine, Rochester, MN 55905, USA
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Kaneki H, Kurokawa M, Ide H. The receptor attributable to C-type natriuretic peptide-induced differentiation of osteoblasts is switched from type B- to type C-natriuretic peptide receptor with aging. J Cell Biochem 2008; 103:753-64. [PMID: 17562543 DOI: 10.1002/jcb.21448] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
C-type natriuretic peptide (CNP) stimulates the differentiation and inhibits the proliferation of osteoblastic lineage cells. In this study, we examined whether the effects of CNP on osteoblastic functions change with aging using calvarial osteoblast-like cells from 25-week-old (young) and 120-week-old (aged) rats. CNP inhibited DNA synthesis and stimulated collagen synthesis and mineralized bone nodule formation. These effects were less pronounced in aged rat cells, suggesting the age-related attenuation of CNP-induced signaling. They were also blocked by the treatment of young rat cells with KT5823, a protein kinase G (PKG) inhibitor, but not by the treatment of aged rat cells with KT5823. CNP stimulated cGMP production in young rat cells, but not in aged rat cells. Natriuretic peptide receptor (NPR)-B, which has a guanylyl cyclase activity domain, and NPR-C, which has no enzyme activity domain, were predominantly expressed in young and aged rat cells, respectively. C-ANF, an NPR-C agonist, mimicked the effects of CNP on the proliferation and differentiation of aged rat cells; these effects were inhibited by the treatment with pertussis toxin (PTX), a Gi protein inhibitor. CNP and C-ANF evoked intracellular levels of inositol-1,4,5-triphosphate and Ca(2+), which are markers for phospholiase C (PLC) activation, in aged rat cells, and the effects of these two peptides were also blocked by the treatment with PTX. From these results, we concluded that CNP acts as a positive regulator of bone formation by osteoblasts and that the signaling pathway for CNP is switched from NPR-B/cGMP/PKG to NPR-C/G(i) protein/PLC with aging.
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Affiliation(s)
- Hiroyuki Kaneki
- Faculty of Pharmaceutical Sciences, Toho University, Miyama 2-2-1, Funabashi, Chiba 274-8510, Japan.
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17
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De Backer O, Elinck E, Sips P, Buys E, Brouckaert P, Lefebvre RA. Role of the soluble guanylyl cyclase alpha1/alpha2 subunits in the relaxant effect of CO and CORM-2 in murine gastric fundus. Naunyn Schmiedebergs Arch Pharmacol 2008; 378:493-502. [PMID: 18563392 DOI: 10.1007/s00210-008-0315-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2007] [Accepted: 05/13/2008] [Indexed: 11/25/2022]
Abstract
Carbon monoxide (CO) has been shown to cause enteric smooth muscle relaxation by activating soluble guanylyl cyclase (sGC). In gastric fundus, the sGCalpha1beta1 heterodimer is believed to be the most important isoform. The aim of our study was to investigate the role of the sGCalpha1/alpha2 subunits in the relaxant effect of CO and CORM-2 in murine gastric fundus using wild-type (WT) and sGCalpha1 knock-out (KO) mice. In WT mice, CO (bolus)-induced relaxations were abolished by the sGC inhibitor 1H-[1,2,4]oxadiazolo-[4,3-a]quinoxalin-1-one (ODQ), while CORM-2- and CO (infusion)-induced relaxations were only partially inhibited by ODQ. In sGCalpha1 KO mice, relaxant responses to CO and CORM-2 were significantly reduced when compared with WT mice, but ODQ still had an inhibitory effect. The sGC sensitizer 1-benzyl-3-(5'-hydroxymethyl-2'-furyl-)-indazol (YC-1) was able to potentiate CO- and CORM-2-induced relaxations in WT mice but lost this potentiating effect in sGCalpha1 KO mice. Both in WT and sGCalpha1 KO mice, CO-evoked relaxations were associated with a significant cGMP increase; however, basal and CO-elicited cGMP levels were markedly lower in sGCalpha1 KO mice. These data indicate that besides the predominant sGCalpha1beta1 isoform, also the less abundantly expressed sGCalpha2beta1 isoform plays an important role in the relaxant effect of CO in murine gastric fundus; however, the sGC stimulator YC-1 loses its potentiating effect towards CO in sGCalpha1 KO mice. Prolonged administration of CO-either by the addition of CORM-2 or by continuous infusion of CO-mediates gastric fundus relaxation in both a sGC-dependent and sGC-independent manner.
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Affiliation(s)
- Ole De Backer
- Heymans Institute of Pharmacology, Ghent University, De Pintelaan 185, 9000, Ghent, Belgium
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18
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Rosmaninho-Salgado J, Araújo IM, Alvaro AR, Duarte EP, Cavadas C. Intracellular signaling mechanisms mediating catecholamine release upon activation of NPY Y1 receptors in mouse chromaffin cells. J Neurochem 2007; 103:896-903. [PMID: 17868303 DOI: 10.1111/j.1471-4159.2007.04899.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The adrenal chromaffin cells synthesize and release catecholamine (mostly epinephrine and norepinephrine) and different peptides, such as the neuropeptide Y (NPY). NPY stimulates catecholamine release through NPY Y1 receptor in mouse chromaffin cells. The aim of our study was to determine the intracellular signaling events coupled to NPY Y1 receptor activation that lead to stimulation of catecholamine release from mouse chromaffin cells. The stimulatory effect of NPY mediated by NPY Y1 receptor activation was lost in the absence of extracellular Ca2+. On the other hand, inhibition of nitric oxide synthase and guanylyl cyclase also decreased the stimulatory effect of NPY. Moreover, catecholamine release stimulated by NPY or by the nitric oxide donor (NOC-18) was inhibited by mitogen-activated protein kinase (MAPK) and protein kinase C inhibitors. In summary, in mouse chromaffin cells, NPY evokes catecholamine release by the activation the NPY Y1 receptor, in a Ca2+-dependent manner, by activating mitogen-activated protein kinase and promoting nitric oxide production, which in turn regulates protein kinase C and guanylyl cyclase activation.
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19
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Rodríguez-Juárez F, Aguirre E, Cadenas S. Relative sensitivity of soluble guanylate cyclase and mitochondrial respiration to endogenous nitric oxide at physiological oxygen concentration. Biochem J 2007; 405:223-31. [PMID: 17441787 PMCID: PMC1904527 DOI: 10.1042/bj20070033] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Nitric oxide (NO) is a widespread biological messenger that has many physiological and pathophysiological roles. Most of the physiological actions of NO are mediated through the activation of sGC (soluble guanylate cyclase) and the subsequent production of cGMP. NO also binds to the binuclear centre of COX (cytochrome c oxidase) and inhibits mitochondrial respiration in competition with oxygen and in a reversible manner. Although sGC is more sensitive to endogenous NO than COX at atmospheric oxygen tension, the more relevant question is which enzyme is more sensitive at physiological oxygen concentration. Using a system in which NO is generated inside the cells in a finely controlled manner, we determined cGMP accumulation by immunoassay and mitochondrial oxygen consumption by high-resolution respirometry at 30 microM oxygen. In the present paper, we report that the NO EC50 of sGC was approx. 2.9 nM, whereas that required to achieve IC50 of respiration was 141 nM (the basal oxygen consumption in the absence of NO was 14+/-0.8 pmol of O2/s per 10(6) cells). In accordance with this, the NO-cGMP signalling transduction pathway was activated at lower NO concentrations than the AMPKs (AMP-activated protein kinase) pathway. We conclude that sGC is approx. 50-fold more sensitive than cellular respiration to endogenous NO under our experimental conditions. The implications of these results for cell physiology are discussed.
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Affiliation(s)
- Félix Rodríguez-Juárez
- CNIC (Centro Nacional de Investigaciones Cardiovasculares), Biology of Nitric Oxide Laboratory, Melchor Fernández Almagro 3, 28029 Madrid, Spain
| | - Enara Aguirre
- CNIC (Centro Nacional de Investigaciones Cardiovasculares), Biology of Nitric Oxide Laboratory, Melchor Fernández Almagro 3, 28029 Madrid, Spain
| | - Susana Cadenas
- CNIC (Centro Nacional de Investigaciones Cardiovasculares), Biology of Nitric Oxide Laboratory, Melchor Fernández Almagro 3, 28029 Madrid, Spain
- To whom correspondence should be addressed (email )
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20
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Abstract
In addition to combination treatment of pulmonary artery hypertension (PHT) with currently available drug options (endothelin-receptor inhibitors, phosphodiesterase-5 inhibitors, prostanoids). Numerous new drugs of other substance groups are being tested in preclinical and clinical studies. Most of the newly tried drugs use previously identified mechanisms of action that are involved in the development and progression of the underlying vascular disease. This has led to a certain paradigm shift which, in addition to vasodilatation and anti-platelet aggregation treatment, increasingly focuses on antiproliferative effects with the aim of preventing or regressing vascular remodelling. Of particular interest in this connection are tyrosine kinase inhibitors, which inhibit the action of such peptide growth factors as platelet-derived growth factor. Imatinib, one of this class of action, has given promising results in experimental studies and several case reports. Another greatly promising approach in the treatment of PHT are activators and simulators of soluble guanylyl cyclase, which are also currently being investigated in clinical trials.
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Affiliation(s)
- H A Ghofrani
- Medizinische Klinik II/V, Abteilung Innere Medizin, Universitätsklinikum Giessen und Marburg, Klinikstrasse 36, 35392 Giessen.
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21
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Abstract
In this issue of the JCI, Stasch and colleagues suggest that a novel drug, BAY 58-2667, potently activates a pool of oxidized and heme-free soluble guanylyl cyclase (sGC; see the related article beginning on page 2552). The increased vasodilatory potency of BAY 58-2667 the authors found in a number of animal models of endothelial dysfunction and in human blood vessels from patients with diabetes suggests that there exists a subphenotype of endothelial dysfunction characterized by receptor-level NO resistance. Diseases associated with NO resistance would appear to be ideally suited for therapies directed at restoring redox homeostasis, sGC activity, and NO sensitivity.
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Affiliation(s)
- Mark T Gladwin
- Vascular Medicine Branch, National Heart, Lung, and Blood Institute, and Critical Care Medicine Department, Clinical Center, National Institutes of Health, Bethesda, Maryland 20892, USA.
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22
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Stasch JP, Schmidt PM, Nedvetsky PI, Nedvetskaya TY, H.S. AK, Meurer S, Deile M, Taye A, Knorr A, Lapp H, Müller H, Turgay Y, Rothkegel C, Tersteegen A, Kemp-Harper B, Müller-Esterl W, Schmidt HH. Targeting the heme-oxidized nitric oxide receptor for selective vasodilatation of diseased blood vessels. J Clin Invest 2006; 116:2552-61. [PMID: 16955146 PMCID: PMC1555649 DOI: 10.1172/jci28371] [Citation(s) in RCA: 357] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2006] [Accepted: 07/11/2006] [Indexed: 01/14/2023] Open
Abstract
ROS are a risk factor of several cardiovascular disorders and interfere with NO/soluble guanylyl cyclase/cyclic GMP (NO/sGC/cGMP) signaling through scavenging of NO and formation of the strong oxidant peroxynitrite. Increased oxidative stress affects the heme-containing NO receptor sGC by both decreasing its expression levels and impairing NO-induced activation, making vasodilator therapy with NO donors less effective. Here we show in vivo that oxidative stress and related vascular disease states, including human diabetes mellitus, led to an sGC that was indistinguishable from the in vitro oxidized/heme-free enzyme. This sGC variant represents what we believe to be a novel cGMP signaling entity that is unresponsive to NO and prone to degradation. Whereas high-affinity ligands for the unoccupied heme pocket of sGC such as zinc-protoporphyrin IX and the novel NO-independent sGC activator 4-[((4-carboxybutyl){2-[(4-phenethylbenzyl)oxy]phenethyl}amino) methyl [benzoic]acid (BAY 58-2667) stabilized the enzyme, only the latter activated the NO-insensitive sGC variant. Importantly, in isolated cells, in blood vessels, and in vivo, BAY 58-2667 was more effective and potentiated under pathophysiological and oxidative stress conditions. This therapeutic principle preferentially dilates diseased versus normal blood vessels and may have far-reaching implications for the currently investigated clinical use of BAY 58-2667 as a unique diagnostic tool and highly innovative vascular therapy.
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Affiliation(s)
- Johannes-Peter Stasch
- Institute of Cardiovascular Research, Bayer HealthCare, Wuppertal, Germany.
Department of Pharmacology, Monash University, Melbourne, Victoria, Australia.
Rudolf-Buchheim-Institute for Pharmacology, Giessen, Germany.
Institute for Biochemistry II, University of Frankfurt Medical School, Frankfurt, Germany.
Helios Klinikum Erfurt, Erfurt, Germany.
Martin-Luther-University, School of Pharmacy, Halle, Germany.
Centre for Vascular Health, Monash University, Melbourne, Victoria, Australia
| | - Peter M. Schmidt
- Institute of Cardiovascular Research, Bayer HealthCare, Wuppertal, Germany.
Department of Pharmacology, Monash University, Melbourne, Victoria, Australia.
Rudolf-Buchheim-Institute for Pharmacology, Giessen, Germany.
Institute for Biochemistry II, University of Frankfurt Medical School, Frankfurt, Germany.
Helios Klinikum Erfurt, Erfurt, Germany.
Martin-Luther-University, School of Pharmacy, Halle, Germany.
Centre for Vascular Health, Monash University, Melbourne, Victoria, Australia
| | - Pavel I. Nedvetsky
- Institute of Cardiovascular Research, Bayer HealthCare, Wuppertal, Germany.
Department of Pharmacology, Monash University, Melbourne, Victoria, Australia.
Rudolf-Buchheim-Institute for Pharmacology, Giessen, Germany.
Institute for Biochemistry II, University of Frankfurt Medical School, Frankfurt, Germany.
Helios Klinikum Erfurt, Erfurt, Germany.
Martin-Luther-University, School of Pharmacy, Halle, Germany.
Centre for Vascular Health, Monash University, Melbourne, Victoria, Australia
| | - Tatiana Y. Nedvetskaya
- Institute of Cardiovascular Research, Bayer HealthCare, Wuppertal, Germany.
Department of Pharmacology, Monash University, Melbourne, Victoria, Australia.
Rudolf-Buchheim-Institute for Pharmacology, Giessen, Germany.
Institute for Biochemistry II, University of Frankfurt Medical School, Frankfurt, Germany.
Helios Klinikum Erfurt, Erfurt, Germany.
Martin-Luther-University, School of Pharmacy, Halle, Germany.
Centre for Vascular Health, Monash University, Melbourne, Victoria, Australia
| | - Arun Kumar H.S.
- Institute of Cardiovascular Research, Bayer HealthCare, Wuppertal, Germany.
Department of Pharmacology, Monash University, Melbourne, Victoria, Australia.
Rudolf-Buchheim-Institute for Pharmacology, Giessen, Germany.
Institute for Biochemistry II, University of Frankfurt Medical School, Frankfurt, Germany.
Helios Klinikum Erfurt, Erfurt, Germany.
Martin-Luther-University, School of Pharmacy, Halle, Germany.
Centre for Vascular Health, Monash University, Melbourne, Victoria, Australia
| | - Sabine Meurer
- Institute of Cardiovascular Research, Bayer HealthCare, Wuppertal, Germany.
Department of Pharmacology, Monash University, Melbourne, Victoria, Australia.
Rudolf-Buchheim-Institute for Pharmacology, Giessen, Germany.
Institute for Biochemistry II, University of Frankfurt Medical School, Frankfurt, Germany.
Helios Klinikum Erfurt, Erfurt, Germany.
Martin-Luther-University, School of Pharmacy, Halle, Germany.
Centre for Vascular Health, Monash University, Melbourne, Victoria, Australia
| | - Martin Deile
- Institute of Cardiovascular Research, Bayer HealthCare, Wuppertal, Germany.
Department of Pharmacology, Monash University, Melbourne, Victoria, Australia.
Rudolf-Buchheim-Institute for Pharmacology, Giessen, Germany.
Institute for Biochemistry II, University of Frankfurt Medical School, Frankfurt, Germany.
Helios Klinikum Erfurt, Erfurt, Germany.
Martin-Luther-University, School of Pharmacy, Halle, Germany.
Centre for Vascular Health, Monash University, Melbourne, Victoria, Australia
| | - Ashraf Taye
- Institute of Cardiovascular Research, Bayer HealthCare, Wuppertal, Germany.
Department of Pharmacology, Monash University, Melbourne, Victoria, Australia.
Rudolf-Buchheim-Institute for Pharmacology, Giessen, Germany.
Institute for Biochemistry II, University of Frankfurt Medical School, Frankfurt, Germany.
Helios Klinikum Erfurt, Erfurt, Germany.
Martin-Luther-University, School of Pharmacy, Halle, Germany.
Centre for Vascular Health, Monash University, Melbourne, Victoria, Australia
| | - Andreas Knorr
- Institute of Cardiovascular Research, Bayer HealthCare, Wuppertal, Germany.
Department of Pharmacology, Monash University, Melbourne, Victoria, Australia.
Rudolf-Buchheim-Institute for Pharmacology, Giessen, Germany.
Institute for Biochemistry II, University of Frankfurt Medical School, Frankfurt, Germany.
Helios Klinikum Erfurt, Erfurt, Germany.
Martin-Luther-University, School of Pharmacy, Halle, Germany.
Centre for Vascular Health, Monash University, Melbourne, Victoria, Australia
| | - Harald Lapp
- Institute of Cardiovascular Research, Bayer HealthCare, Wuppertal, Germany.
Department of Pharmacology, Monash University, Melbourne, Victoria, Australia.
Rudolf-Buchheim-Institute for Pharmacology, Giessen, Germany.
Institute for Biochemistry II, University of Frankfurt Medical School, Frankfurt, Germany.
Helios Klinikum Erfurt, Erfurt, Germany.
Martin-Luther-University, School of Pharmacy, Halle, Germany.
Centre for Vascular Health, Monash University, Melbourne, Victoria, Australia
| | - Helmut Müller
- Institute of Cardiovascular Research, Bayer HealthCare, Wuppertal, Germany.
Department of Pharmacology, Monash University, Melbourne, Victoria, Australia.
Rudolf-Buchheim-Institute for Pharmacology, Giessen, Germany.
Institute for Biochemistry II, University of Frankfurt Medical School, Frankfurt, Germany.
Helios Klinikum Erfurt, Erfurt, Germany.
Martin-Luther-University, School of Pharmacy, Halle, Germany.
Centre for Vascular Health, Monash University, Melbourne, Victoria, Australia
| | - Yagmur Turgay
- Institute of Cardiovascular Research, Bayer HealthCare, Wuppertal, Germany.
Department of Pharmacology, Monash University, Melbourne, Victoria, Australia.
Rudolf-Buchheim-Institute for Pharmacology, Giessen, Germany.
Institute for Biochemistry II, University of Frankfurt Medical School, Frankfurt, Germany.
Helios Klinikum Erfurt, Erfurt, Germany.
Martin-Luther-University, School of Pharmacy, Halle, Germany.
Centre for Vascular Health, Monash University, Melbourne, Victoria, Australia
| | - Christiane Rothkegel
- Institute of Cardiovascular Research, Bayer HealthCare, Wuppertal, Germany.
Department of Pharmacology, Monash University, Melbourne, Victoria, Australia.
Rudolf-Buchheim-Institute for Pharmacology, Giessen, Germany.
Institute for Biochemistry II, University of Frankfurt Medical School, Frankfurt, Germany.
Helios Klinikum Erfurt, Erfurt, Germany.
Martin-Luther-University, School of Pharmacy, Halle, Germany.
Centre for Vascular Health, Monash University, Melbourne, Victoria, Australia
| | - Adrian Tersteegen
- Institute of Cardiovascular Research, Bayer HealthCare, Wuppertal, Germany.
Department of Pharmacology, Monash University, Melbourne, Victoria, Australia.
Rudolf-Buchheim-Institute for Pharmacology, Giessen, Germany.
Institute for Biochemistry II, University of Frankfurt Medical School, Frankfurt, Germany.
Helios Klinikum Erfurt, Erfurt, Germany.
Martin-Luther-University, School of Pharmacy, Halle, Germany.
Centre for Vascular Health, Monash University, Melbourne, Victoria, Australia
| | - Barbara Kemp-Harper
- Institute of Cardiovascular Research, Bayer HealthCare, Wuppertal, Germany.
Department of Pharmacology, Monash University, Melbourne, Victoria, Australia.
Rudolf-Buchheim-Institute for Pharmacology, Giessen, Germany.
Institute for Biochemistry II, University of Frankfurt Medical School, Frankfurt, Germany.
Helios Klinikum Erfurt, Erfurt, Germany.
Martin-Luther-University, School of Pharmacy, Halle, Germany.
Centre for Vascular Health, Monash University, Melbourne, Victoria, Australia
| | - Werner Müller-Esterl
- Institute of Cardiovascular Research, Bayer HealthCare, Wuppertal, Germany.
Department of Pharmacology, Monash University, Melbourne, Victoria, Australia.
Rudolf-Buchheim-Institute for Pharmacology, Giessen, Germany.
Institute for Biochemistry II, University of Frankfurt Medical School, Frankfurt, Germany.
Helios Klinikum Erfurt, Erfurt, Germany.
Martin-Luther-University, School of Pharmacy, Halle, Germany.
Centre for Vascular Health, Monash University, Melbourne, Victoria, Australia
| | - Harald H.H.W. Schmidt
- Institute of Cardiovascular Research, Bayer HealthCare, Wuppertal, Germany.
Department of Pharmacology, Monash University, Melbourne, Victoria, Australia.
Rudolf-Buchheim-Institute for Pharmacology, Giessen, Germany.
Institute for Biochemistry II, University of Frankfurt Medical School, Frankfurt, Germany.
Helios Klinikum Erfurt, Erfurt, Germany.
Martin-Luther-University, School of Pharmacy, Halle, Germany.
Centre for Vascular Health, Monash University, Melbourne, Victoria, Australia
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23
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Singh G, Maguire JJ, Kuc RE, Skepper JN, Fidock M, Davenport AP. Characterization of the snake venom ligand [125I]-DNP binding to natriuretic peptide receptor-A in human artery and potent DNP mediated vasodilatation. Br J Pharmacol 2006; 149:838-44. [PMID: 17043672 PMCID: PMC2014690 DOI: 10.1038/sj.bjp.0706924] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND AND PURPOSE The natriuretic peptides, ANP and BNP, modulate vascular smooth muscle tone in human conduit arteries. Surprisingly, the natriuretic peptide receptor-A (NPR-A) has not been visualized using radioligand binding in these vessels. A new member of this peptide family, Dendroaspis natriuretic peptide (DNP) identified from snake venom, has been proposed to be present in human plasma and endothelial cells. Also, recently a novel radioligand, [(125)I]-DNP, has been characterized as selective for NPR-A in human heart. EXPERIMENTAL APPROACH Our aims were to investigate expression and function of NPR-A receptors in human mammary artery using [(125)I]-DNP to quantify receptor density, immunocytochemistry to delineate the cellular distribution of the receptor and in vitro pharmacology to compare DNP induced vasodilatation to that of ANP. KEY RESULTS Saturable, sub-nanomolar affinity [(125)I]-DNP binding was detected to smooth muscle of mammary artery, with receptor density of approximately 2 fmol mg(-1) protein, comparable to that of other vasoactive peptides. NPR-A immunoreactivity was localised to vascular smooth muscle cells and this was confirmed with fluorescence dual labelling. NPR-A expression was not detected in the endothelium. Like ANP, DNP fully reversed the constrictor response to ET-1 in endothelium intact or denuded mammary artery, with comparable nanomolar potencies. CONCLUSIONS AND IMPLICATIONS This is the first characterization of NPR-A in human mammary artery using [(125)I]-DNP and we provide evidence for the presence of receptor protein on vascular smooth muscle cells, but not endothelial cells. This implies that the observed vasodilatation is predominantly mediated via direct activation of smooth muscle NPR-A.
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MESH Headings
- Adrenomedullin/pharmacology
- Amino Acid Sequence
- Atrial Natriuretic Factor/pharmacology
- Calcitonin Gene-Related Peptide/pharmacology
- Dose-Response Relationship, Drug
- Elapid Venoms/metabolism
- Elapid Venoms/pharmacology
- Fluorescent Antibody Technique, Indirect
- Guanylate Cyclase/analysis
- Guanylate Cyclase/drug effects
- Guanylate Cyclase/metabolism
- Humans
- Immunohistochemistry
- In Vitro Techniques
- Intercellular Signaling Peptides and Proteins
- Ligands
- Mammary Arteries/chemistry
- Mammary Arteries/drug effects
- Mammary Arteries/metabolism
- Microscopy, Confocal
- Models, Biological
- Molecular Sequence Data
- Muscle, Smooth, Vascular/chemistry
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Peptides/metabolism
- Peptides/pharmacology
- Protein Binding
- Radiopharmaceuticals/metabolism
- Receptors, Atrial Natriuretic Factor/analysis
- Receptors, Atrial Natriuretic Factor/drug effects
- Receptors, Atrial Natriuretic Factor/metabolism
- Vasodilation/drug effects
- Vasodilator Agents/metabolism
- Vasodilator Agents/pharmacology
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Affiliation(s)
- G Singh
- Clinical Pharmacology Unit, University of Cambridge, Centre for Clinical Investigation, Addenbrooke's Hospital Cambridge, UK
| | - J J Maguire
- Clinical Pharmacology Unit, University of Cambridge, Centre for Clinical Investigation, Addenbrooke's Hospital Cambridge, UK
- Author for correspondence:
| | - R E Kuc
- Clinical Pharmacology Unit, University of Cambridge, Centre for Clinical Investigation, Addenbrooke's Hospital Cambridge, UK
| | - J N Skepper
- Department of Anatomy, Multi-Imaging Centre, University of Cambridge Cambridge, UK
| | - M Fidock
- Pfizer Global Research & Development Sandwich, Kent, UK
| | - A P Davenport
- Clinical Pharmacology Unit, University of Cambridge, Centre for Clinical Investigation, Addenbrooke's Hospital Cambridge, UK
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24
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Crane JK, Azar SS, Stam A, Newburg DS. Oligosaccharides from human milk block binding and activity of the Escherichia coli heat-stable enterotoxin (STa) in T84 intestinal cells. J Nutr 2006; 124:2358-64. [PMID: 16856316 DOI: 10.1093/jn/124.12.358] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Enterotoxin-producing Escherichia coli are major causes of pediatric diarrhea in developing countries. The heat-stable enterotoxin of Escherichia coli (STa) causes diarrhea by virtue of its ability to bind to and stimulate intestinal membrane-bound guanylate cyclase, generating cyclic GMP (cGMP). Previous work showed that a fucosylated oligosaccharide fraction of human milk was able to protect suckling mice from the secretory effects of STa, but the mechanism of the protection could not be determined. Oligosaccharide fractions from human milk were tested for their ability to block the biochemical effects of STa in T84 cells, a human colon carcinoma line responsive to the toxin. Total and fucosylated oligosaccharide fractions were found to inhibit STa-stimulated guanylate cyclase activity in T84 cell membranes and cGMP production in intact T84 cells by 60-80%. In addition, the total oligosaccharide fraction and the fucosylated oligosaccharide fraction inhibited 125I-STa binding significantly (17% and 27% inhibition, respectively). These findings demonstrate the protective activity of human milk oligosaccharides against STa in a human-derived cell line and show that the biochemical step blocked by oligosaccharides is STa-mediated stimulation of guanylate cyclase. This represents a novel mechanism by which human milk oligosaccharides protect against diarrhea.
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Affiliation(s)
- J K Crane
- University of Texas-Houston Health Sciences Center, Houston, TX 77030, USA
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25
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Elitsur N, Lorenz JN, Hawkins JA, Rudolph JA, Witte D, Yang LE, McDonough AA, Cohen MB. The proximal convoluted tubule is a target for the uroguanylin-regulated natriuretic response. J Pediatr Gastroenterol Nutr 2006; 43 Suppl 1:S74-81. [PMID: 16819406 DOI: 10.1097/01.mpg.0000228092.36089.7c] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
OBJECTIVES AND METHODS Guanylin and uroguanylin are peptides synthesized in the intestine and kidney that are postulated to have both paracrine and endocrine functions, forming a potential enteric-renal link to coordinate salt ingestion with natriuresis. To explore the in vivo role of guanylin and uroguanylin in the regulation of sodium excretion, we used gene-targeted mice in which the uroguanylin, guanylin or the peptide receptor guanylate cyclase C gene expression had been ablated. RESULTS Metabolic balance studies demonstrated that there was impaired excretion of a sodium load in uroguanylin (but not in guanylin or guanylate cyclase C) knockout mice. Uroguanylin-dependent natriuresis occurred without an increase in circulating prouroguanylin. A distinct morphological phenotype was present in the proximal convoluted tubules of uroguanylin knockout animals after an enteral salt loading. Marked vacuolization of the proximal convoluted tubule epithelial cells was observed by using light and electron microscopy. There was also a change in the distribution of the sodium hydrogen exchanger 3 (NHE3) after an enteral salt loading. In wild-type animals, there was a partial redistribution of NHE3 from the villus fraction to the less accessible submicrovillus membrane compartment, but this effect was less apparent in uroguanylin knockout animals, presumably resulting in greater Na/H exchange. CONCLUSIONS Together, these findings further establish a role for uroguanylin in fluid homeostasis and support a role for uroguanylin as an integral component of a signaling mechanism that mediates changes in Na excretion in response to an enteral salt loading. Proximal tubular NHE3 activity is a possible target for uroguanylin-mediated changes in Na excretion.
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MESH Headings
- Analysis of Variance
- Animals
- Biomarkers/blood
- Biomarkers/urine
- Blotting, Western
- Cyclic GMP/urine
- Enteral Nutrition
- Fluorescent Antibody Technique, Indirect
- Gastrointestinal Hormones/blood
- Gastrointestinal Hormones/metabolism
- Guanylate Cyclase/drug effects
- Guanylate Cyclase/metabolism
- Kidney Tubules, Proximal/drug effects
- Kidney Tubules, Proximal/metabolism
- Kidney Tubules, Proximal/physiopathology
- Mice
- Mice, Knockout
- Microscopy, Electron
- Models, Animal
- Natriuresis/drug effects
- Natriuretic Peptides/blood
- Natriuretic Peptides/metabolism
- Potassium Channels/drug effects
- Potassium Channels/metabolism
- Receptors, Enterotoxin
- Receptors, Guanylate Cyclase-Coupled
- Receptors, Peptide/drug effects
- Receptors, Peptide/metabolism
- Sodium Chloride, Dietary/administration & dosage
- Sodium-Hydrogen Exchanger 3
- Sodium-Hydrogen Exchangers/drug effects
- Sodium-Hydrogen Exchangers/metabolism
- Time Factors
- Water-Electrolyte Balance/drug effects
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Affiliation(s)
- Noeet Elitsur
- Division of Gastroenterology, Hepatology and Nutrition, Cincinnati Children's Hospital Medical Center, and the University of Cincinnati, OH 45229, USA
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26
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Aylett P. Digestive Disease Week 2006. 21-15 May 2006, Los Angeles, CA, USA. IDrugs 2006; 9:449-51. [PMID: 16821149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Affiliation(s)
- Peter Aylett
- Thomson Scientific, Middlesex House, 34-42 Cleveland Street, London, W1T 4JE, UK.
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27
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Abstract
Many details of the generic pathway for induction of NF-kappaB have been delineated, but it is still not clear how multiple, diverse receptor systems are able to converge on this evolutionarily conserved family of transcription factors. Recent studies have shown that the CARMA1, Bcl10, and MALT1 proteins are critical for coupling the common elements of the NF-kappaB pathway to the T-cell receptor (TCR) and CD28. We previously demonstrated a role for the serine/threonine kinase Akt in CD28-mediated NF-kappaB induction. Using a CARMA1-deficient T-cell line, we have now found that the CARMA complex is required for induction of NF-kappaB by Akt, in cooperation with protein kinase C activation. Furthermore, using a novel selective inhibitor of Akt, we confirm that Akt plays a modulatory role in NF-kappaB induction by the TCR and CD28. Finally, we provide evidence for a physical and functional interaction between Akt and CARMA and for Akt-dependent phosphorylation of Bcl10. Therefore, in T cells, Akt impinges upon NF-kappaB signaling through at least two separate mechanisms.
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Affiliation(s)
- Preeti Narayan
- Department of Immunology, BST E-1056, University of Pittsburgh School of Medicine, 200 Lothrop St., Pittsburgh, PA 15261, USA
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28
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Müller D, Cortes-Dericks L, Budnik LT, Brunswig-Spickenheier B, Pancratius M, Speth RC, Mukhopadhyay AK, Middendorff R. Homologous and lysophosphatidic acid-induced desensitization of the atrial natriuretic peptide receptor, guanylyl cyclase-A, in MA-10 leydig cells. Endocrinology 2006; 147:2974-85. [PMID: 16527839 DOI: 10.1210/en.2006-0092] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The cardiac hormone atrial natriuretic peptide (ANP) signals via interaction with a plasma membrane receptor, which has guanylyl cyclase (GC) activity and is referred to as GC-A. Desensitization of GC-A is thought to represent a physiologically important regulatory mechanism, but the signaling pathways implicated and cell type-specific effects are still poorly understood. Here we demonstrate that sustained exposure to either ANP itself or the bioactive lipid lysophosphatidic acid (LPA) elicits GC-A desensitization in MA-10 Leydig cells. Both reactions show similar kinetics and evoke equal decreases (by 40%) in GC-A hormone responsiveness. Homologous (ANP induced) desensitization, in which cGMP is generated as second messenger, is blocked by distinct cAMP-dependent protein kinase [protein kinase A (PKA)] inhibitors, H 89, and Rp-8-CPT-cAMPs, providing evidence that PKA mediates the reaction. Accordingly, the ANP/cGMP-elicited effects are mimicked by a cAMP analog, 8-bromo-cAMP. The LPA-induced (heterologous) desensitization is not blocked by PKA inhibition, indicating a different signaling pathway. LPA, but not ANP, enhances ERK phosphorylation and induces cell rounding together with a dramatic reorganization of actin filaments. Consistent with the identification of LPA receptor (LPA2 and LPA3) gene expression, the findings are indicative of LPA receptor-mediated reactions. This study demonstrates for the first time coexistence of homologous and heterologous desensitization of GC-A in the same cell type, reveals that these reactions are mediated by different pathways, and identifies a novel cross talk between phospholipid and natriuretic peptide signaling. The morphoregulatory activities exerted by LPA suggest a crucial role for Leydig cell physiology.
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Affiliation(s)
- Dieter Müller
- Institute of Anatomy and Cell Biology, Justus-Liebig-University, Giessen, Germany.
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29
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Abstract
Natriuretic peptides (NPs) may work as neuromodulators through their associated receptors [NP receptors (NPRs)]. By immunocytochemistry, we showed that NPR-A and NPR-B were expressed abundantly on both ON-type and OFF-type bipolar cells (BCs) in rat retina, including the dendrites, somata, and axon terminals. Whole-cell recordings made from isolated ON-type BCs further showed that brain natriuretic peptide (BNP) suppressed GABAA receptor-, but not GABAC receptor-, mediated currents of the BCs, which was blocked by the NPR-A antagonist anantin. The NPR-C agonist c-ANF [des(Gln18, Ser19, Gln20, Leu21, Gly22)ANF(4-23)-NH2] did not suppress GABAA currents. The BNP effect on GABAA currents was abolished with preincubation with the pGC-A/B antagonist HS-142-1 but mimicked by application of 8-bromoguanosine-3',5'-cyclomonophosphate. These results suggest that elevated levels of intracellular cGMP caused by activation of NPR-A may mediate the BNP effect. Internal infusion of the cGMP-dependent protein kinase G (PKG) inhibitor KT5823 essentially blocked the BNP-induced reduction of GABAA currents. Moreover, calcium imaging showed that BNP caused a significant elevation of intracellular calcium that could be caused by increased calcium release from intracellular stores by PKG. The BNP effect was blocked by the ryanodine receptor modulators caffeine, ryanodine, and ruthenium red but not by the IP3 receptor antagonists heparin and xestospongin-C. Furthermore, the BNP effect was abolished after application of the blocker of endoplasmic reticulum Ca2+-ATPase thapsigargin and greatly reduced by the calmodulin inhibitors W-7 and calmidazolium. We therefore conclude that the increased calcium release from ryanodine-sensitive calcium stores by BNP may be responsible for the BNP-caused GABAA response suppression in ON-type BCs through stimulating calmodulin.
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MESH Headings
- Animals
- Atrial Natriuretic Factor/pharmacology
- Caffeine/pharmacology
- Calcium/metabolism
- Calcium Channels
- Calcium Signaling/drug effects
- Calcium-Transporting ATPases/antagonists & inhibitors
- Calmodulin/antagonists & inhibitors
- Calmodulin/physiology
- Carbazoles/pharmacology
- Cyclic GMP/analogs & derivatives
- Cyclic GMP/pharmacology
- Cyclic GMP-Dependent Protein Kinases/physiology
- GABA-A Receptor Antagonists
- Guanylate Cyclase/drug effects
- Guanylate Cyclase/physiology
- Heparin/pharmacology
- Imidazoles/pharmacology
- Indoles/pharmacology
- Inositol 1,4,5-Trisphosphate Receptors
- Macrocyclic Compounds
- Male
- Membrane Potentials/drug effects
- Natriuretic Peptide, Brain/antagonists & inhibitors
- Natriuretic Peptide, Brain/pharmacology
- Natriuretic Peptide, Brain/physiology
- Oxazoles/pharmacology
- Patch-Clamp Techniques
- Peptide Fragments/pharmacology
- Peptides, Cyclic/pharmacology
- Polysaccharides/pharmacology
- Protein Kinase Inhibitors/pharmacology
- Rats
- Rats, Sprague-Dawley
- Receptors, Atrial Natriuretic Factor/drug effects
- Receptors, Atrial Natriuretic Factor/physiology
- Receptors, Cytoplasmic and Nuclear/antagonists & inhibitors
- Receptors, GABA/physiology
- Receptors, GABA-A/drug effects
- Retinal Bipolar Cells/drug effects
- Retinal Bipolar Cells/physiology
- Ruthenium Red/pharmacology
- Ryanodine/pharmacology
- Ryanodine Receptor Calcium Release Channel/drug effects
- Thapsigargin/pharmacology
- gamma-Aminobutyric Acid/pharmacology
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Affiliation(s)
- Yong-Chun Yu
- Institute of Neurobiology, Fudan University, Shanghai 200433, China
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30
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Mullershausen F, Lange A, Mergia E, Friebe A, Koesling D. Desensitization of NO/cGMP signaling in smooth muscle: blood vessels versus airways. Mol Pharmacol 2006; 69:1969-74. [PMID: 16510560 DOI: 10.1124/mol.105.020909] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The NO/cGMP signaling pathway plays a major role in the cardiovascular system, in which it is involved in the regulation of smooth muscle tone and inhibition of platelet aggregation. Under pathophysiological conditions such as endothelial dysfunction, coronary artery disease, and airway hyperreactivity, smooth muscle containing arteries and bronchi are of great pharmacological interest. In these tissues, NO mediates its effects by stimulating guanylyl cyclase (GC) to form cGMP; the subsequent increase in cGMP is counteracted by the cGMP-specific phosphodiesterase (PDE5), which hydrolyzes cGMP. In platelets, allosteric activation of PDE5 by cGMP paralleled by phosphorylation has been shown to govern the sensitivity of NO/cGMP signaling. Here, we demonstrate that the functional responsiveness to NO correlates with the relative abundance of GC and PDE5 in aortic and bronchial tissue, respectively. We show a sustained desensitization of the NO-induced relaxation of aortic and bronchial rings caused by a short-term exposure to NO. The NO treatment caused heterologous desensitization of atrial natriuretic peptide-induced relaxation, whereas relaxation by the cGMP analog 8-pCPT-cGMP was unperturbed. Impaired relaxation was shown to be paralleled by PDE5 phosphorylation; this indicates enhanced cGMP degradation as a mechanism of desensitization. In summary, our results demonstrate the physiological impact of PDE5 activation on the control of smooth muscle tone and provide an explanation for the apparent impairment of NO-induced vasorelaxation.
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Affiliation(s)
- Florian Mullershausen
- Institut für Pharmakologie und Toxikologie, Ruhr-Universität Bochum, Medizinische Fakultät MA N1, Universitätsstrasse 150, 44780 Bochum, Germany
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31
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Marcoli M, Cervetto C, Paluzzi P, Guarnieri S, Raiteri M, Maura G. Nitric oxide-evoked glutamate release and cGMP production in cerebellar slices: control by presynaptic 5-HT1D receptors. Neurochem Int 2006; 49:12-9. [PMID: 16469416 DOI: 10.1016/j.neuint.2005.12.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2005] [Revised: 12/05/2005] [Accepted: 12/19/2005] [Indexed: 11/22/2022]
Abstract
We previously reported that pre- and postsynaptic 5-hydroxytryptamine (5-HT) receptors effectively control glutamatergic transmission in adult rat cerebellum. To investigate where 5-HT acts in the glutamate ionotropic receptors/nitric oxide/guanosine 3',5'-cyclic monophosphate (cGMP) pathway, in the present study 5-HT modulation of the cGMP response to the nitric oxide donor S-nitroso-penicillamine (SNAP) was studied in adult rat cerebellar slices. While cGMP elevation produced by high-micromolar SNAP was insensitive to 5-HT, 1 microM SNAP, expected to release nitric oxide in the low-nanomolar concentration range, elicited cGMP production and endogenous glutamate release both of which could be prevented by activating presynaptic 5-HT1D receptors. Released nitric oxide appeared responsible for cGMP production and glutamate release evoked by 1 microM SNAP, as both the effects were mimicked by the structurally unrelated nitric oxide donor 2-(N,N-diethylamino)-diazenolate-2-oxide (0.1 microM). Dependency of the 1 microM SNAP-evoked release of glutamate on external Ca2+, sensitivity to presynaptic release-regulating receptors and dependency on ionotropic glutamate receptor functioning, suggest that nitric oxide stimulates exocytotic-like, activity-dependent glutamate release. Activation of ionotropic glutamate receptors/nitric oxide synthase/guanylyl cyclase pathway by endogenously released glutamate was involved in the cGMP response to 1 microM SNAP, as blockade of NMDA/non-NMDA receptors, nitric oxide synthase or guanylyl cyclase, abolished the cGMP response. To conclude, in adult rat cerebellar slices low-nanomolar exogenous nitric oxide could facilitate glutamate exocytotic-like release possibly from parallel fibers that subsequently activated the glutamate ionotropic receptors/nitric oxide/cGMP pathway. Presynaptic 5-HT1D receptors could regulate the nitric oxide-evoked release of glutamate and subsequent cGMP production.
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Affiliation(s)
- Manuela Marcoli
- Department of Experimental Medicine, Pharmacology and Toxicology Section, University of Genoa, Viale Cembrano 4, Genoa, Italy
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32
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Kowalczyk E, Kopff A, Kopff M, Błaszczyk J, Fijałkowski P, Kowalski J. [Nitric oxide metabolism]. Wiad Lek 2006; 59:889-93. [PMID: 17427511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Nitric oxide is an important mediator of physiological and pathological processes. It is a lipophilic molecule that contains a single unpaired electron which causes NO to be chemically reactive, and to function as a free radical with a short lifetime. NO can act by direct and indirect effects. Direct effects occur between NO and specific biological molecules whereas indirect effects are mediated by reactive nitrogen oxide species (RNOS) formed from the reaction of NO either with oxygen or superoxide. This review discusses the metabolic pathways of NO.
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Affiliation(s)
- Edward Kowalczyk
- Zakładu Fizjologii Człowieka i Biofizyki, Uniwersytetu Medycznego w Lodzi.
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33
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Cameron-Schaefer S, Kondo K, Ishige A, Tsuyama S, Uchida K, Hanawa T, Suematsu M, Watanabe K. Maintaining the redox-balance intact: gosha-jinki-gan but not insulin activates retinal soluble guanylate cyclase in diabetic rats. Ophthalmic Res 2005; 38:95-104. [PMID: 16374052 DOI: 10.1159/000090451] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2005] [Accepted: 08/29/2005] [Indexed: 11/19/2022]
Abstract
Strategies to prevent hyperglycemia-induced cytotoxic reactive oxygen species in the retina include the prevention of free radical production, activation of radical-scavenging capacities and inhibition of aldose reductase. This study examined the effect of the standardized Japanese herbal extract product gosha-jinki-gan (GJG) in comparison to insulin treatment in the rat retina. Diabetes was induced in male Wistar rats by single injection of streptozotocin (50 mg/kg i.p.). At 6 and 12 weeks, eye-cups were removed for immunohistochemistry. At 12 weeks, lipid peroxidation (tested with the antiacrolein antibody, Ab5F6) was enhanced significantly in the untreated diabetic group. This effect was absent in both treatment groups, notably in the outer retina. A similar result was obtained for nitrotyrosine overproduction. As an early treatment effect, GJG -- but not insulin -- enhanced soluble guanylate cyclase (sGC) activation (using the function-sensing antibody, MoAb 3221). GJG not only reduces nitroxidative stress and lipid peroxidation in the retina, it also ameliorates glucose metabolism within the cells. We propose that the high glucose turnover in the insulin-treated model disturbs the intracellular redox equilibrium, one result of which might be the impaired sGC activation.
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34
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Ribeiro AC, Kapás L. The effects of intracerebroventricular application of 8-Br-cGMP and LY-83,583, a guanylyl cyclase inhibitor, on sleep-wake activity in rats. Brain Res 2005; 1049:25-33. [PMID: 15922313 DOI: 10.1016/j.brainres.2005.04.067] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2005] [Revised: 04/18/2005] [Accepted: 04/22/2005] [Indexed: 10/25/2022]
Abstract
Cyclic GMP is the second messenger that mediates most of the neuronal effects of nitric oxide (NO). Several lines of evidence suggest that NO-ergic mechanisms play an integral role in the regulation of vigilance. In the present study, we tested the effects of the activation of cGMP-receptive mechanisms and the inhibitor of guanylyl cyclase (GC), LY-83,583, on sleep in rats. Rats were injected intracerebroventricularly (icv) with 0.16, 4, 100, and 500 microg or 2.5 mg 8-Br-cGMP, a membrane-permeable analogue of cGMP, or 1 and 100 microg LY-83,583. Administration of 4 microg-2.5 mg 8-Br-cGMP increased wakefulness and suppressed rapid-eye-movement sleep (REMS) and non-REMS (NREMS) in rats when given before dark onset but not when given before the light period. The GC inhibitor LY-83,583 strongly promoted NREMS and suppressed REMS during the light period of the day. Furthermore, LY-83,583 induced striking increases in the delta-wave activity of the electroencephalogram (EEG) during NREMS, whereas EEG activity above the 4.5 Hz wave range was suppressed in all vigilance states. Our finding that cGMP has an arousal-promoting activity is in line with the hypothesis that NO/cGMP signaling pathway is involved in the regulation of vigilance.
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Affiliation(s)
- Ana C Ribeiro
- Department of Biological Sciences, Fordham University, 441 E. Fordham Road, Bronx, NY 10458, USA
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35
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Abstract
The C-type natriuretic (CNP) peptide signals through the type B natriuretic peptide receptor (NPR-B) in vascular smooth muscle cells to activate the particulate guanylyl cyclase activity intrinsic to that receptor and raise cellular cyclic GMP levels. In the present study, we demonstrate that CNP down-regulates the expression of this receptor leading to a reduction in NPR-B activity. Pretreatment of rat aortic smooth muscle cells with CNP reduces NPR-B activity, NPR-B protein levels, NPR2 (NPR-B gene) mRNA levels, and NPR2 promoter activity. The decrease in NPR2 promoter activity is dependent on DNA sequence present between -441 and -134 relative to the transcription start site. The reduction in NPR2 gene expression appears to operate through generation of cyclic GMP. 8-Bromo cyclic GMP, a membrane-permeable cyclic GMP analog, reduced NPR2 mRNA levels and NPR2 promoter activity. Atrial natriuretic peptide, which signals through the type A natriuretic peptide receptor (NPR-A) to increase cyclic GMP levels in these cells, also reduced NPR-B mRNA levels and inhibited NPR-B promoter activity; however, this inhibition was not additive with that produced by CNP, implying that the two ligands traffic over a common signal transduction pathway. This report provides the first documentation that CNP is capable of autoregulating the expression of its cognate receptor.
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MESH Headings
- Animals
- Aorta/cytology
- Aorta/metabolism
- Atrial Natriuretic Factor/pharmacology
- Cells, Cultured
- Cyclic GMP/analogs & derivatives
- Cyclic GMP/metabolism
- Cyclic GMP/pharmacology
- DNA/genetics
- Down-Regulation
- Drug Combinations
- Guanylate Cyclase/drug effects
- Guanylate Cyclase/genetics
- Guanylate Cyclase/metabolism
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/metabolism
- Myocytes, Smooth Muscle/metabolism
- Natriuretic Peptide, C-Type/pharmacology
- Promoter Regions, Genetic/drug effects
- RNA, Messenger/antagonists & inhibitors
- RNA, Messenger/metabolism
- Rats
- Receptors, Atrial Natriuretic Factor/drug effects
- Receptors, Atrial Natriuretic Factor/genetics
- Receptors, Atrial Natriuretic Factor/metabolism
- Transcription Initiation Site
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Affiliation(s)
- Dolkun Rahmutula
- Department of Medicine and Diabetes Center, 1109 HSW, University of California at San Francisco, San Francisco, California 94143-0540, USA
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36
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Priviero FBM, Baracat JS, Teixeira CE, Claudino MA, De Nucci G, Antunes E. MECHANISMS UNDERLYING RELAXATION OF RABBIT AORTA BY BAY 41-2272, A NITRIC OXIDE-INDEPENDENT SOLUBLE GUANYLATE CYCLASE ACTIVATOR. Clin Exp Pharmacol Physiol 2005; 32:728-34. [PMID: 16173929 DOI: 10.1111/j.1440-1681.2005.04262.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
1. The compound BAY 41-2272 (5-cyclopropyl-2-[1-(2-fluoro-benzyl)-1H-pyrazolo[3,4-b]pyridin-3-yl]-pyrimidin-4-ylamine) has been described as a potent, nitric oxide (NO)-independent, stimulator of soluble guanylate cyclase. In the present study, the mechanisms underlying the relaxant effect of BAY 41-2272 in endothelium-intact and -denuded precontracted rabbit aortic rings were investigated. 2. Male New Zealand white rabbits were anaesthetized with pentobarbital sodium. Aortic rings were transferred to 10 mL organ baths containing oxygenated and warmed Krebs' solution. Tissues were connected to force-displacement transducers and changes in isometric force were recorded. Aortic rings were precontracted submaximally with phenylephrine (1 micromol/L). 3. The addition of BAY 41-2272 (0.01-10 micromol/L) to the organ bath produced concentration-dependent relaxations of the aortic rings with a higher potency in endothelium-intact (pEC50 6.59 +/- 0.05) compared with endothelium-denuded (pEC50 6.19 +/- 0.04; P < 0.05) preparations. No differences in maximal responses were observed in either preparation. The NO synthesis inhibitor NG-nitro-L-arginine methyl ester (100 micromol/L) produced a 2.1-fold rightward shift in endothelium-intact (P < 0.01) rings, but had no effect in endothelium-denuded rings. The soluble guanylate cyclase inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ; 1 micromol/L) caused significant rightward shifts of the concentration-response curves to BAY 41-2272 of 4.9- and 2.6-fold in endothelium-intact and -denuded rings, respectively. The phosphodiesterase-5 inhibitor sildenafil (0.1 micromol/L) significantly potentiated the relaxant effects of BAY 41-2272 in both endothelium-intact and -denuded rings. 4. At 1 micromol/L, BAY 41-2272 significantly elevated the aortic cGMP content above basal levels in both endothelium-intact and -denuded rings. Furthermore, ODQ reduced BAY 41-2272-elicited increases in cGMP content by 17 and 90% in endothelium-intact and -denuded rings, respectively (P < 0.01). 5. In conclusion, BAY 41-2272 potently relaxes endothelium-intact and -denuded rabbit aortic rings. The basal release of endothelium-derived NO enhances BAY 41-2272-induced relaxations, suggesting a synergistic effect of BAY 41-2272 and NO on soluble guanylate cyclase. In addition, the endothelium-independent relaxation involves both GMP-dependent and -independent mechanisms.
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Affiliation(s)
- Fernanda B M Priviero
- Department of Pharmacology, Faculty of Medical Sciences, State University of Campinas (UNICAMP), Campinas, Brazil
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37
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Doggrell SA. Clinical potential of nitric oxide-independent soluble guanylate cyclase activators. Curr Opin Investig Drugs 2005; 6:874-8. [PMID: 16187686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
A major problem with using nitrates in the treatment of ischemic heart disease is that tolerance develops to their vasodilatory actions. YC-1 was used as the lead compound to synthesize further nitric oxide-independent soluble guanylate cyclase activators, including BAY-41-2272 and BAY-41-8543. A nitric oxide and heme-independent activator of soluble guanylate cyclase, BAY-58-2667, was subsequently discovered by high-throughput screening. Tolerance to the vasodilatory actions of BAY-41-8543 and BAY-58-2667 does not develop. Results from animal studies have suggested that these compounds may have potential in the treatment of ischemic heart disease, essential and pulmonary hypertension, congestive heart failure, glomerulonephritis and erectile dysfunction.
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Affiliation(s)
- Sheila A Doggrell
- Division of Health Practice, Auckland University of Technology-Akoranga Campus, Auckland, New Zealand.
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38
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Penna C, Cappello S, Mancardi D, Raimondo S, Rastaldo R, Gattullo D, Losano G, Pagliaro P. Post-conditioning reduces infarct size in the isolated rat heart: role of coronary flow and pressure and the nitric oxide/cGMP pathway. Basic Res Cardiol 2005; 101:168-79. [PMID: 16132172 DOI: 10.1007/s00395-005-0543-6] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2004] [Revised: 05/25/2005] [Accepted: 05/25/2005] [Indexed: 12/30/2022]
Abstract
We aimed to assess the role of the nitric oxide (NO)-cGMP pathway in cardioprotection by brief intermittent ischemias at the onset of reperfusion (i.e., post-conditioning (Post-con)). We also evaluated the role of coronary flow and pressure in Post-con. Rat isolated hearts perfused at constant- flow or -pressure underwent 30 min global ischemia and 120 min reperfusion. Post-con obtained with brief ischemias of different duration (modified, MPost-con) was compared with Post-con obtained with ischemias of identical duration (classical, C-Post-con) and with ischemic preconditioning (IP). Infarct size was evaluated using nitro-blue tetrazolium staining and lactate dehydrogenase (LDH) release. In the groups, NO synthase (NOS) or guanylyl-cyclase (GC) was inhibited with LNAME and ODQ, respectively. In the subgroups, the enzyme immunoassay technique was used to quantify cGMP release. In the constant-flow model, M-Post-con and C-Post-con were equally effective, but more effective than IP in reducing infarct size. The cardioprotection by M-Post-con was only blunted by the NOS-inhibitor, but was abolished by the GC-antagonist. Post-ischemic cGMP release was enhanced by MPost-con. In the constant-pressure model IP, M-Post-con and C-Post-con were equally effective in reducing infarct size. Post-con protocols were more effective in the constant-flow than in the constant-pressure model. In all groups, LDH release during reperfusion was proportional to infarct size. In conclusion, Post-con depends upon GC activation, which can be achieved by NOS-dependent and NOS-independent pathways. The benefits of M- and CPost-con are similar. However, protection by Post-con is greater in the constant-flow than in the constant-pressure model.
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Affiliation(s)
- Claudia Penna
- Dipartimento di Scienze Cliniche e Biologiche dell'Università di Torino, Orbassano, TO, Italy
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39
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Cutajar MC, Edwards TM, Ng KT. Inhibition of endogenous carbon monoxide production induces transient retention losses in the day-old chick when trained using a single trial passive avoidance learning task. Neurobiol Learn Mem 2005; 83:243-50. [PMID: 15820860 DOI: 10.1016/j.nlm.2005.01.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2003] [Revised: 11/08/2004] [Accepted: 01/24/2005] [Indexed: 10/25/2022]
Abstract
Carbon monoxide (CO) is most often thought of as an exogenous toxin rather than as a possible endogenous nootrope. However, a limited number of studies have suggested that CO is necessary in memory processing for at least some tasks. While nitric oxide (NO) and CO are known activators of guanylyl cyclase (GC), only the effect of NO on GC has been extensively investigated as a mechanism underlying memory processing. The aim of the present study was to determine if inhibition of CO production would have an effect on memory processing. Using chicks trained on a single trial passive avoidance task, inhibition of CO production using zinc (II) deuteroporphyrin IX 2,4-bis ethylene glycol (ZnBG; 5 microM) resulted in two transient retention losses occurring at around 40 and 130 min post-training. The timing of these transient retention losses was similar to those observed following inhibition of GC, using the same species and task in a previous study. This supports the notion that CO is necessary in memory processing for this task and may act through a GC-dependent mechanism. As ZnBG also directly inhibits GC or nitric oxide synthase (NOS) at high concentrations, a second experiment was carried-out to confirm the specificity of ZnBG for heme oxygenase (HO) at the concentration used. The action of ZnBG was challenged with the HO agonist hemin (100 microM) and the transient deficits were abolished. This confirmed that the action of ZnBG on memory was through a CO-related mechanism rather than directly on GC or NOS. In this way the specificity of ZnBG (5 microM) for HO could be confirmed. The results support a role for endogenous CO in memory processing, possibly through activation of GC. In addition, the transient retention losses observed following administration of ZnBG suggest that CO may be necessary for memory retrieval and not formation as previously thought.
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Affiliation(s)
- M C Cutajar
- Department of Psychology, School of Psychology, Psychiatry and Psychological Medicine, Monash University 3800, Vic., Australia
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40
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Wu CH, Chang WC, Chang GY, Kuo SC, Teng CM. The inhibitory mechanism of YC-1, a benzyl indazole, on smooth muscle cell proliferation: an in vitro and in vivo study. J Pharmacol Sci 2005; 94:252-60. [PMID: 15037810 DOI: 10.1254/jphs.94.252] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
The pharmacological mechanisms of a synthetic compound 1-benzyl-3-(5'-hydroxymethyl-2'-furyl) indazole (YC-1) in preventing smooth muscle cell proliferation remains to be elucidated. The present study was aimed to explore the effects of YC-1 on certain molecules responsible for cell proliferation, including transforming growth factor (TGF)-beta1, soluble guanylyl cyclase (sGC) and focal adhesion kinase (FAK). The in vivo assay was correlated to the in vitro results of YC-1 on vascular stenosis. YC-1 was applied topically via a pluronic gel onto the balloon-injured rat carotid arteries, which were then harvested two weeks later for histological analysis. Our in vitro results showed that TGF-beta1 was suppressed by YC-1 by 50%. The translational level of sGC was threefold activated by YC-1 while the transcription level of sGC was increased up to 24-fold. FAK, the molecule responsible for cell proliferation and migration, was suppressed by YC-1 on the translational levels for 72%. These in vitro results were in consistent with the in vivo observation that the area ratio of neointima to media was reduced by YC-1. This study provides insights into the pharmacological mechanisms of YC-1 in preventing abnormal smooth muscle cell proliferation and thus supports the use of YC-1 as an adjuvant therapy for balloon injury-induced restenosis.
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MESH Headings
- Administration, Topical
- Animals
- Aorta, Thoracic/cytology
- Aorta, Thoracic/drug effects
- Carotid Artery, Common/pathology
- Catheterization/adverse effects
- Cell Division/drug effects
- Cells, Cultured
- Dose-Response Relationship, Drug
- Focal Adhesion Kinase 1
- Focal Adhesion Protein-Tyrosine Kinases
- Glyceraldehyde-3-Phosphate Dehydrogenases/drug effects
- Glyceraldehyde-3-Phosphate Dehydrogenases/genetics
- Guanylate Cyclase/drug effects
- Guanylate Cyclase/genetics
- Guanylate Cyclase/metabolism
- Imidazoles/chemistry
- Imidazoles/pharmacology
- Indazoles/administration & dosage
- Indazoles/chemistry
- Indazoles/pharmacokinetics
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/growth & development
- Poloxamer/chemistry
- Poloxamer/metabolism
- Protein-Tyrosine Kinases/antagonists & inhibitors
- Protein-Tyrosine Kinases/drug effects
- Protein-Tyrosine Kinases/genetics
- RNA, Messenger
- Rats
- Receptors, Enterotoxin
- Receptors, Guanylate Cyclase-Coupled
- Receptors, Peptide/drug effects
- Receptors, Peptide/genetics
- Receptors, Peptide/metabolism
- Transforming Growth Factor beta/antagonists & inhibitors
- Transforming Growth Factor beta/metabolism
- Tunica Intima/drug effects
- Tunica Intima/growth & development
- Tunica Intima/pathology
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Affiliation(s)
- Chieh-Hsi Wu
- Department of Pharmacology, China Medical University, Taichung, Taiwan.
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41
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Duport S, Garthwaite J. Pathological consequences of inducible nitric oxide synthase expression in hippocampal slice cultures. Neuroscience 2005; 135:1155-66. [PMID: 16165295 DOI: 10.1016/j.neuroscience.2005.06.035] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2005] [Revised: 05/16/2005] [Accepted: 06/09/2005] [Indexed: 12/31/2022]
Abstract
The generation of toxic concentrations of nitric oxide by the inducible nitric oxide synthase expressed in microglia and other brain cell types is frequently invoked as a causative factor in neurodegeneration. Experiments were carried out on slice cultures of rat hippocampus to test this hypothesis. Exposure of the slices to bacterial lipopolysaccharide plus interferon-gamma led to a time-dependent expression of functional inducible nitric oxide synthase that was found only in microglia. Microglial activation by other means, such as physical damage, was not associated with inducible nitric oxide synthase expression. Damage and cell death in slices expressing inducible nitric oxide synthase was evaluated over a period of 6 days, but none was found. Consistent with this result, cGMP measurements indicated that the average local nitric oxide concentration remained in the low nanomolar range. When the microglial population was expanded to a density three-fold above normal by applying granulocyte-macrophage colony stimulating factor, however, lipopolysaccharide plus interferon-gamma provoked neurodegeneration that could be blocked by an inducible nitric oxide synthase inhibitor. The associated nitric oxide concentration in the slices was saturating for guanylyl cyclase-coupled nitric oxide receptors, signifying at least 10 nM. It is concluded that inducible nitric oxide synthase is expressed in microglia only in response to specific stimuli involving the innate immune system, and that the resulting level of nitric oxide in intact brain tissue is normally too low to inflict damage directly. Quantities of nitric oxide sufficient to contribute directly or indirectly to pathology could be produced should the density of microglia become high enough, although caution must be exercised in extrapolating this finding to the human brain in vivo.
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Affiliation(s)
- S Duport
- Wolfson Institute for Biomedical Research, University College London, Gower Street, London WC1E 6BT, UK
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42
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Morton DB, Langlais KK, Stewart JA, Vermehren A. Comparison of the properties of the five soluble guanylyl cyclase subunits in Drosophila melanogaster. J Insect Sci 2005; 5:12. [PMID: 16341244 PMCID: PMC1307573 DOI: 10.1093/jis/5.1.12] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/07/2004] [Accepted: 12/05/2004] [Indexed: 05/05/2023]
Abstract
The Drosophila melanogaster genome contains 5 genes that code for soluble guanylyl cyclase subunits. Two of these genes code for subunits, Gycalpha-99B and Gycbeta-100B, which form a conventional NO-sensitive guanylyl cyclase and the other three code for atypical subunits, Gyc-88E, Gyc-89Da and Gyc-89Db. The properties and distribution of Gyc-88E and Gyc-89Db have previously been described and here Gyc-89Da is described. Gyc-89Da only forms an active guanylyl cyclase when co-expressed with Gyc-88E. The three atypical subunits probably form two different heterodimers in vivo: Gyc-88E/89Da and Gyc-88E/89Db. Both of these heterodimers were slightly stimulated by NO donors and Gyc-88E/89Da showed a greater activation by Mn2+, with an increase in Vmax and a decrease in K(m), compared to Gyc-88E/89Db. Both Gyc-88E/89Da and Gyc-88E/89Db were expressed in neurons in both the peripheral and central nervous system. Although all three heterodimeric soluble guanylyl cyclases in D. melanogaster can be activated by NO and inhibited by ODQ, the atypical enzymes can be distinguished from the conventional soluble guanylyl cyclase by their sensitivity to the NO-independent activators YC-1 and BAY 41-2272, which will only activate the conventional enzyme.
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Affiliation(s)
- David B Morton
- Department of Integrative Biosciences, Oregon Health & Science University, Portland, Oregon 97239, USA.
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43
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Veltman DM, Roelofs J, Engel R, Visser AJWG, Van Haastert PJM. Activation of soluble guanylyl cyclase at the leading edge during Dictyostelium chemotaxis. Mol Biol Cell 2004; 16:976-83. [PMID: 15601898 PMCID: PMC545927 DOI: 10.1091/mbc.e04-08-0701] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Dictyostelium contains two guanylyl cyclases, GCA, a 12-transmembrane enzyme, and sGC, a homologue of mammalian soluble adenylyl cyclase. sGC provides nearly all chemoattractant-stimulated cGMP formation and is essential for efficient chemotaxis toward cAMP. We show that in resting cells the major fraction of the sGC-GFP fusion protein localizes to the cytosol, and a small fraction is associated to the cell cortex. With the artificial substrate Mn2+/GTP, sGC activity and protein exhibit a similar distribution between soluble and particulate fraction of cell lysates. However, with the physiological substrate Mg2+/GTP, sGC in the cytosol is nearly inactive, whereas the particulate enzyme shows high enzyme activity. Reconstitution experiments reveal that inactive cytosolic sGC acquires catalytic activity with Mg2+/GTP upon association to the membrane. Stimulation of cells with cAMP results in a twofold increase of membrane-localized sGC-GFP, which is accompanied by an increase of the membrane-associated guanylyl cyclase activity. In a cAMP gradient, sGC-GFP localizes to the anterior cell cortex, suggesting that in chemotacting cells, sGC is activated at the leading edge of the cell.
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Affiliation(s)
- Douwe M Veltman
- Department of Biochemistry, University of Groningen, 9747 AG Groningen, The Netherlands
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44
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Fürst R, Brueckl C, Kuebler WM, Zahler S, Krötz F, Görlach A, Vollmar AM, Kiemer AK. Atrial natriuretic peptide induces mitogen-activated protein kinase phosphatase-1 in human endothelial cells via Rac1 and NAD(P)H oxidase/Nox2-activation. Circ Res 2004; 96:43-53. [PMID: 15569826 DOI: 10.1161/01.res.0000151983.01148.06] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The cardiovascular hormone atrial natriuretic peptide (ANP) exerts anti-inflammatory effects on tumor necrosis factor-alpha-activated endothelial cells by inducing mitogen-activated protein kinase (MAPK) phosphatase-1 (MKP-1). The underlying mechanisms are as yet unknown. We aimed to elucidate the signaling pathways leading to an induction of MKP-1 by ANP in primary human endothelial cells. By using antioxidants, generation of reactive oxygen species (ROS) was shown to be crucially involved in MKP-1 upregulation. ANP was found to increase ROS formation in cultured cells as well as in the endothelium of intact rat lung vessels. We applied NAD(P)H oxidase (Nox) inhibitors (apocynin and gp91ds-tat) and revealed this enzyme complex to be crucial for superoxide generation and MKP-1 expression. Moreover, by performing Nox2/4 antisense experiments, we identified Nox2 as the critically involved Nox homologue. Pull-down assays and confocal microscopy showed that ANP activates the small Rho-GTPase Rac1. Transfection of a dominant-negative (RacN17) and constitutively active Rac1 mutant (RacV12) indicated that ANP-induced superoxide generation and MKP-1 expression are mediated via Rac1 activation. ANP-evoked production of superoxide was found to activate c-Jun N-terminal kinase (JNK). Using specific inhibitors, we linked ANP-induced JNK activation to MKP-1 expression and excluded an involvement of protein kinase C, extracellular signal-regulated kinase, and p38 MAPK. MKP-1 induction was shown to depend on activation of the transcription factor activator protein-1 (AP-1) by using electrophoretic mobility shift assay and AP-1 decoys. In summary, our work provides insights into the mechanisms by which ANP induces MKP-1 and shows that ANP is a novel endogenous activator of endothelial Rac1 and Nox/Nox2.
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MESH Headings
- Acetophenones/pharmacology
- Animals
- Atrial Natriuretic Factor/pharmacology
- Atrial Natriuretic Factor/physiology
- Capillaries
- Cell Cycle Proteins/biosynthesis
- Cell Cycle Proteins/genetics
- Cells, Cultured/drug effects
- Cells, Cultured/metabolism
- Cyclic GMP/analogs & derivatives
- Cyclic GMP/metabolism
- Cyclic GMP/pharmacology
- Cycloheximide/pharmacology
- DNA, Antisense/pharmacology
- Dual Specificity Phosphatase 1
- Endothelial Cells/drug effects
- Endothelial Cells/metabolism
- Endothelium, Vascular/cytology
- Enzyme Induction/drug effects
- Enzyme Induction/physiology
- Glycoproteins/pharmacology
- Guanylate Cyclase/drug effects
- Guanylate Cyclase/physiology
- Humans
- Immediate-Early Proteins/biosynthesis
- Immediate-Early Proteins/genetics
- JNK Mitogen-Activated Protein Kinases/metabolism
- Lung/blood supply
- MAP Kinase Kinase 4
- MAP Kinase Signaling System/drug effects
- MAP Kinase Signaling System/physiology
- Membrane Glycoproteins/biosynthesis
- Membrane Glycoproteins/genetics
- Membrane Glycoproteins/physiology
- Membrane Proteins/biosynthesis
- Membrane Proteins/genetics
- Mitogen-Activated Protein Kinase Kinases/metabolism
- NADPH Oxidase 1
- NADPH Oxidase 2
- NADPH Oxidase 4
- NADPH Oxidase 5
- NADPH Oxidases/biosynthesis
- NADPH Oxidases/genetics
- NADPH Oxidases/physiology
- Oligonucleotides, Antisense/pharmacology
- Phosphoprotein Phosphatases/biosynthesis
- Phosphoprotein Phosphatases/genetics
- Protein Phosphatase 1
- Protein Tyrosine Phosphatases/biosynthesis
- Protein Tyrosine Phosphatases/genetics
- RNA, Messenger/biosynthesis
- RNA, Messenger/genetics
- Rats
- Rats, Sprague-Dawley
- Reactive Oxygen Species/metabolism
- Receptors, Atrial Natriuretic Factor/drug effects
- Receptors, Atrial Natriuretic Factor/physiology
- Recombinant Fusion Proteins/physiology
- Transcription Factor AP-1/metabolism
- Transfection
- Umbilical Veins/cytology
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Affiliation(s)
- Robert Fürst
- Department of Pharmacy, University of Munich, Germany
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45
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Abstract
The natriuretic peptide receptor guanylate cyclases are members of the membrane-bound guanylate cyclase family. Atrial natriuretic pepticle (ANP) stimulates guanylate cyclase A, which is predominantly expressed in the rat parotid gland. ATP is well known to increase ANP-stimulated guanylate cyclase, with Mg2+ as a cofactor. We investigated the regulation of guanylate cyclase activity in rat parotid membranes with Mn2+ as a cofactor, because enzyme activity was much higher with Mn2+ than with Mg2+. ANP (10(-7)M) stimulated guanylate cyclase activity to 120%-130% of the control level, and ATP (0.1-1.0 mM) depressed its activity, with or without ANP, to 70%-80% of the control. Enzyme activity was increased by the addition of phosphate (5-20 mM). In the presence of phosphate (5 mM), guanylate cyclase with and without ANP was maximally stimulated to 5- and 6.6-fold of the control, respectively. The net stimulation of guanylate cyclase by ANP was increased at ATP concentrations between 0.2 and 0.5 mM in the presence of phosphate (5 mM or 10 mM), but no change was observed in the absence of phosphate. Phosphate not only stimulated guanylate cyclase in the absence of ATP but altered the ATP regulation of ANP-stimulated guanylate cyclase. The stimulation of guanylate cyclase by phosphate may depend on a peculiarity of rat parotid membranes.
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Affiliation(s)
- Tomoko Nashida
- Department of Biochemistry, The Nippon Dental University School of Dentistry at Niigata, 1-8 Hamaura-cho, Niigata, Japan.
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Jankowski M, Reis AM, Wang D, Gutkowska J. Postnatal ontogeny of natriuretic peptide systems in the rat hypothalamus. Brain Res Dev Brain Res 2004; 152:39-46. [PMID: 15283993 DOI: 10.1016/j.devbrainres.2004.05.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 05/31/2004] [Indexed: 01/09/2023]
Abstract
Our study has attempted to clarify the developmental profile of atrial natriuretic peptide (ANP) and C-type natriuretic peptide (CNP) along with the expression of their receptors in the rat hypothalamus. Radioimmunoassay (RIA) of dissected hypothalamic tissue revealed that ANP rose from 167 +/- 50 pg/mg protein immediately after birth to 516 +/- 78 pg/mg protein in the next 24 h and to 928 +/- 100 pg/mg protein by postnatal day (PD) 5. A second increment of ANP in the hypothalamus was noted between PD 10 and PD 20 (from 780 +/- 110 to 2,650 +/- 136 pg/mg protein). These changes were not gender-related and consistent with a rise of ANP mRNA. Diethylstilbestrol treatment of immature rats increased hypothalamic ANP concentration from 2.11 +/- 0.24 to 2.97 +/- 0.44 ng/mg protein (P<0.001), but equine chorionic gonadotropin had no effect, indicating that estrogen is a potential stimulus of ANP only at supra-physiological concentrations. CNP, the most abundant natriuretic peptide in the brain, gradually increased in the developing hypothalamus, but did not plateau at PD 20. Reverse transcription-polymerase chain reaction analysis of ANP receptor mRNA demonstrated higher guanylyl cyclase (GC) A, no changes in GC-B, and lower C-receptor levels in adult compared to newborn rats. In conclusion, we have shown that hypothalamic ANP undergoes a dramatic rise after birth, and progresses further until the 3rd postnatal week. ANP and CNP changes in the developing hypothalamus can influence brain maturation.
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Affiliation(s)
- Marek Jankowski
- Centre de recherche, Centre hospitalier de l'Université de Montreal-Hôtel-Dieu, Pavillon de Bullion, 3850 rue Saint-Urbain, Montreal, Quebec H2W 1T7, Canada.
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Abstract
Twenty five new triazolecarboxamides related to YC-1 were prepared and tested for their antiplatelet (in vitro) and antithrombotic (in vivo) activities. Five of them inhibited the aggregation of blood platelets (Born test, inducer collagen) with IC50 values between 90 and 130 microM. Nine compounds exhibited significant antithrombotic properties with an inhibition of thrombus formation between 11 and 7%. Only one compound (8c) showed both, in vitro and in vivo effects. In vitro, the most active compounds were 11c and 12d. They inhibit platelet aggregation with IC50 = 90 and 95 microM. In vivo, 10a showed the strongest inhibition of thrombus formation with 11% in arterioles (5% in venules) after a single oral dose of 60 mg/kg. With serotonin as inducer both, 11c and 12d, showed lower IC50 values namely 25 or 30 microM, respectively. Additional antiplatelet activities were found for 11c against adrenaline (IC50 = 25 microM) and for 12d against platelet activating factor (PAF) (IC50 = 15 microM) as inducer.
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Affiliation(s)
- Anke Cwiklicki
- Institut für Pharmazie, Freie Universität Berlin, Berlin, Germany
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48
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Miller MR, Okubo K, Roseberry MJ, Webb DJ, Megson IL. Extracellular nitric oxide release mediates soluble guanylate cyclase-independent vasodilator action of spermine NONOate: comparison with other nitric oxide donors in isolated rat femoral arteries. J Cardiovasc Pharmacol 2004; 43:440-51. [PMID: 15076229 DOI: 10.1097/00005344-200403000-00016] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Nitric oxide (NO) and NO donors exhibit actions that are not entirely mediated by soluble guanylate cyclase (sGC). The site of NO release may influence the involvement of sGC-independent effects. Here we use spermine NONOate (SPER/NO) to release NO extracellularly, compared with other NO donors. Isolated rat femoral arteries were perfused luminally and perfusion pressure monitored. Vessels were contracted with phenylephrine (2-14 microM) in the presence of an NO synthase inhibitor (N(omega)-nitro-L-arginine methyl ester; 20 microM). Vasodilator responses to NO donors were assessed before and after perfusion of an sGC inhibitor (1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one; ODQ; 20 microM), NO scavengers (hemoglobin; Hb & hydroquinone; HQ), and a superoxide generator (duroquinone; DQ). ODQ (20 microM) abolished the vasodilator responses to glyceryl trinitrate (10(-8) - 10(-3) M), and sodium nitroprusside (10(-8) - 10(-4) M), which release NO intracellularly. ODQ (20 microM) attenuated, but failed to abolish, the vasodilator responses to SPER/NO (10(-6) - 10(-3) M). ODQ abolished responses to S-nitrosoglutathione and S-nitroso-N-valeryl-D-penicillamine (10(-8) - 10(-4) M), but a small residual vasodilatation remained in response to 10(-3) M. In the presence of ODQ, the remaining vasodilatation to SPER/NO was all but abolished by scavengers of extracellular NO (Hb; 10 microM, HQ; 100 microM). Superoxide generation (DQ; 100 microM) also attenuated ODQ-resistant vasodilatation. The data suggest that, in rat femoral arteries, NO donors that are capable of releasing extracellular NO cause vasodilatation that is only partially mediated by sGC. Lack of augmentation of sGC-independent effects by superoxide suggests that they are not mediated by peroxynitrite.
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Affiliation(s)
- M R Miller
- Centre for Cardiovascular Science, Hugh Robson Building, University of Edinburgh, Edinburgh, Scotland, UK
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49
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Itaba S, Chijiiwa Y, Matsuzaka H, Motomura Y, Nawata H. Presence of C-type natriuretic peptide (CNP) in guinea pig caecum: role and mechanisms of CNP in circular smooth muscle relaxation. Neurogastroenterol Motil 2004; 16:375-82. [PMID: 15198660 DOI: 10.1111/j.1365-2982.2004.00506.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The distribution and role of C-type natriuretic peptide (CNP) in the gastrointestinal tract are still unclear. This study was designed to investigate the distribution of CNP in guinea pig caecum and the inhibitory mechanisms of CNP in caecal circular smooth muscle cells. CNP immunoreactivity was recognized in smooth muscle cells, myenteric and submucosal neurons of the caecum by immunohistochemistry. CNP mRNA expression was demonstrated in both freshly dispersed and cultured smooth muscle cells by reverse-transcription polymerase chain reaction. CNP inhibited 1 nmol L(-1) cholecystokinin octapeptide (CCK-8)-induced smooth muscle cell contraction in a dose-dependent manner, with an IC(50) value of 0.24 nmol L(-1), and significantly stimulated the production of intracellular cyclic guanosine monophosphate. Furthermore, inhibitors of both soluble and particulate guanylate cyclase (GC) partially but significantly inhibited CNP-induced relaxation. This is the first report demonstrating that CNP localizes in gastrointestinal smooth muscle cells and the enteric nervous system. These results suggest that CNP acts locally through neural and autocrine pathways to modulate colonic motility via both particulate and soluble GC systems. These two pathways appear to be through natriuretic peptide receptor (NPR)-B, which has particulate GC domain, and NPR-C, which activates soluble GC, judging from previous findings that NPR-A is not expressed in these cells.
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Affiliation(s)
- S Itaba
- Department of Molecular Genetics, Division of Molecular and Clinical Genetics, Medical Institute of Bioregulation, Kyushu University, Beppu 874-0838, Japan.
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50
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Schrofner S, Zsombok A, Hermann A, Kerschbaum HH. Nitric oxide decreases a calcium-activated potassium current via activation of phosphodiesterase 2 in Helix U-cells. Brain Res 2004; 999:98-105. [PMID: 14746926 DOI: 10.1016/j.brainres.2003.11.038] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
In the present study, we investigated the underlaying mechanism of nitric oxide (NO) and cGMP on the decline of a Ca2+-activated potassium (KCa) current in U-cells of the right parietal ganglion of the pulmonate snail, Helix pomatia. Using a two-electrode voltage-clamp technique, we activated a KCa-current either by opening of endogenous voltage-gated Ca2+-channels during depolarizing voltage steps or by ionophoretic injection of Ca2+ via a third electrode containing 100 mM Ca2+. KCa-current amplitude in U-cells was sensitive to Ba2+, TEA, iberiotoxin, kaliotoxin and charybdotoxin (ChTX), but not to 4-aminopyridine (4-AP) (up to 30 mM) and apamin (up to 300 nM). Thus, the biophysical and pharmacological profile of the KCa-current in U-cells shares similarities with the large-conductance KCa channel (BKCa). The NO-donor sodium nitroprusside (SNP) or S-nitro-N-acetylpenicillamine (SNAP) as well as NO-gas decreased the KCa-current amplitude and decreased the rate of KCa-current activation elicited by Ca2+-injection. Decline of the current amplitude and decrease of activation of KCa-current were qualitatively mimicked by the membrane-permeable cGMP analogue dibutyryl-cGMP (db-cGMP). NO-induced decrease of KCa-current was blocked by methylene blue (50 microM), an inhibitor of the guanylyl-cyclase, and by erytho-9-(2-hydroxyl-3-nonyl) adenine (EHNA) (100 microM), an inhibitor of the cGMP-stimulated phosphodiesterase 2 (PDE2). These experiments suggest that the NO-mediated decrease of KCa-current in U-cells results from synthesis of cGMP by activation of a guanylyl-cyclase and subsequent activation of PDE2.
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MESH Headings
- 3',5'-Cyclic-AMP Phosphodiesterases/drug effects
- 3',5'-Cyclic-AMP Phosphodiesterases/metabolism
- Animals
- Calcium/metabolism
- Calcium/pharmacology
- Calcium Channels/drug effects
- Calcium Channels/physiology
- Calcium Signaling/drug effects
- Calcium Signaling/physiology
- Cyclic GMP/biosynthesis
- Cyclic Nucleotide Phosphodiesterases, Type 2
- Ganglia, Invertebrate/cytology
- Ganglia, Invertebrate/drug effects
- Ganglia, Invertebrate/enzymology
- Guanylate Cyclase/drug effects
- Guanylate Cyclase/metabolism
- Helix, Snails/cytology
- Helix, Snails/drug effects
- Helix, Snails/enzymology
- Membrane Potentials/drug effects
- Membrane Potentials/physiology
- Nervous System/cytology
- Nervous System/drug effects
- Nervous System/enzymology
- Neurons/drug effects
- Neurons/enzymology
- Nitric Oxide/metabolism
- Nitric Oxide Donors/pharmacology
- Organ Culture Techniques
- Potassium Channel Blockers/pharmacology
- Potassium Channels, Calcium-Activated/drug effects
- Potassium Channels, Calcium-Activated/physiology
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Affiliation(s)
- Siegfried Schrofner
- Department of Molecular Neurobiology and Cellular Physiology, Institute of Zoology, University of Salzburg, Hellbrunnerstr. 34, 5020 Salzburg, Austria
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