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Animal models of erectile dysfunction. J Pharmacol Toxicol Methods 2015; 76:43-54. [PMID: 26279495 DOI: 10.1016/j.vascn.2015.07.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Revised: 07/02/2015] [Accepted: 07/30/2015] [Indexed: 12/19/2022]
Abstract
Erectile dysfunction (ED) is a prevalent male sexual dysfunction with profound adverse effects on the physical and the psychosocial health of men and, subsequently, on their partners. The expanded use of various types of rodent models has produced some advances in the study of ED, and neurophysiological studies using various animal models have provided important insights into human sexual dysfunction. At present, animal models play a key role in exploring and screening novel drugs designed to treat ED.
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Nunes KP, Teixeira CE, Priviero FBM, Toque HA, Webb RC. Beneficial effect of the soluble guanylyl cyclase stimulator BAY 41-2272 on impaired penile erection in db/db-/- type II diabetic and obese mice. J Pharmacol Exp Ther 2015; 353:330-9. [PMID: 25740897 DOI: 10.1124/jpet.114.220970] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Type 2 diabetes mellitus (DM2) and obesity are major risk factors for erectile dysfunction (ED). In diabetes, increased oxidative stress leads to decreased nitric oxide (NO) bioavailability, and diabetic patients appear to be less responsive to conventional therapy with phosphodiesterase type 5 inhibitors. We investigated whether the soluble guanylyl cyclase stimulator BAY 41-2272 (5-cyclopropyl-2-[1-(2-fluoro-benzyl)-1H-pyrazolo[3,4-b]pyridine-3-yl]pyrimidin-4ylamine) is effective in improving impaired corpus cavernosum (CC) relaxation in obese DM2 mice by reducing oxidative stress. Adult db/db(-/-) mice or their lean db(/+) littermates were used to assess vascular function, cGMP levels, antioxidant status, NADPH oxidase expression, and superoxide formation in the absence or presence of BAY 41-2272. Results showed that BAY 41-2272 (10(-8) to 10(-5) M) potently relaxed CC from db(/+) or db/db(-/-) mice in a similar manner. BAY 41-2272 significantly enhanced both endothelium-dependent and nitrergic relaxation induced by electrical field stimulation (EFS), and improved the impaired relaxation to acetylcholine and EFS in the diabetic animals in a concentration-dependent manner (10(-8) to 10(-7) M). BAY 41-2272 increased cGMP levels and potentiated relaxation responses to exogenous NO in CC. Total antioxidant status was reduced in plasma and urine whereas expression of vascular NADPH oxidase subunits (gp91phox, p22phox, and p47phox) was increased in the CC of db/db(-/-) mice, suggesting a state of oxidative stress. These effects were prevented by BAY 41-2272 in a concentration-dependent manner. These results suggest that BAY 41-2272 improves CC relaxation in db/db(-/-) mice by increasing cGMP and augmenting antioxidant status, making this drug is a potential novel candidate to treat ED.
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Affiliation(s)
- Kenia Pedrosa Nunes
- Department of Cell and Regenerative Biology, University of Wisconsin, Madison, Wisconsin (K.P.N.); Laboratory of Multidisciplinary Research, Universidade São Francisco, Bragança Paulista, Brazil (F.B.M.P.); and Departments of Physiology (C.E.T., R.C.W.) and Pharmacology and Toxicology (H.A.T.), Georgia Regents University, Augusta, Georgia
| | - Cleber E Teixeira
- Department of Cell and Regenerative Biology, University of Wisconsin, Madison, Wisconsin (K.P.N.); Laboratory of Multidisciplinary Research, Universidade São Francisco, Bragança Paulista, Brazil (F.B.M.P.); and Departments of Physiology (C.E.T., R.C.W.) and Pharmacology and Toxicology (H.A.T.), Georgia Regents University, Augusta, Georgia
| | - Fernanda B M Priviero
- Department of Cell and Regenerative Biology, University of Wisconsin, Madison, Wisconsin (K.P.N.); Laboratory of Multidisciplinary Research, Universidade São Francisco, Bragança Paulista, Brazil (F.B.M.P.); and Departments of Physiology (C.E.T., R.C.W.) and Pharmacology and Toxicology (H.A.T.), Georgia Regents University, Augusta, Georgia
| | - Haroldo A Toque
- Department of Cell and Regenerative Biology, University of Wisconsin, Madison, Wisconsin (K.P.N.); Laboratory of Multidisciplinary Research, Universidade São Francisco, Bragança Paulista, Brazil (F.B.M.P.); and Departments of Physiology (C.E.T., R.C.W.) and Pharmacology and Toxicology (H.A.T.), Georgia Regents University, Augusta, Georgia
| | - R Clinton Webb
- Department of Cell and Regenerative Biology, University of Wisconsin, Madison, Wisconsin (K.P.N.); Laboratory of Multidisciplinary Research, Universidade São Francisco, Bragança Paulista, Brazil (F.B.M.P.); and Departments of Physiology (C.E.T., R.C.W.) and Pharmacology and Toxicology (H.A.T.), Georgia Regents University, Augusta, Georgia
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Yilmaz D, Bayatli N, Un O, Kadowitz PJ, Sikka SC, Gur S. The Effect of Intracavernosal Avanafil, a Newer Phosphodiesterase-5 Inhibitor, on Neonatal Type 2 Diabetic Rats With Erectile Dysfunction. Urology 2014; 83:508.e7-12. [DOI: 10.1016/j.urology.2013.10.021] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Revised: 10/05/2013] [Accepted: 10/08/2013] [Indexed: 11/30/2022]
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Greene SJ, Gheorghiade M, Borlaug BA, Pieske B, Vaduganathan M, Burnett JC, Roessig L, Stasch JP, Solomon SD, Paulus WJ, Butler J. The cGMP signaling pathway as a therapeutic target in heart failure with preserved ejection fraction. J Am Heart Assoc 2013; 2:e000536. [PMID: 24334823 PMCID: PMC3886746 DOI: 10.1161/jaha.113.000536] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Key Words] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Stephen J Greene
- Center for Cardiovascular Innovation, Northwestern University Feinberg School of Medicine, Chicago, IL
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Oudot A, Behr-Roussel D, Poirier S, Sandner P, Bernabé J, Alexandre L, Giuliano F. Combination of BAY 60-4552 and vardenafil exerts proerectile facilitator effects in rats with cavernous nerve injury: a proof of concept study for the treatment of phosphodiesterase type 5 inhibitor failure. Eur Urol 2011; 60:1020-6. [PMID: 21839578 DOI: 10.1016/j.eururo.2011.07.052] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2011] [Accepted: 07/21/2011] [Indexed: 11/24/2022]
Abstract
BACKGROUND Radical prostatectomy (RP) is frequently responsible for erectile dysfunction (ED). Post-RP patients often show a failure to respond to phosphodiesterase type 5 (PDE5) inhibitors. OBJECTIVE The acute effect of BAY 60-4552, the soluble guanylate cyclase (sGC) stimulator, and vardenafil were evaluated alone or in combination on erectile responses to electrical stimulation of the cavernous nerve (ES CN) in rats with cavernous nerve (CN) crush injury-induced ED. DESIGN, SETTING, AND PARTICIPANTS Male adult Sprague-Dawley rats underwent laparotomy (sham, n=10) or bilateral CN crush injury (n=56). After 3 wk of recovery, erectile function was evaluated under urethane anaesthesia following ES CN at different frequencies. MEASUREMENTS The acute effects of intravenous (IV) injection of vehicle, vardenafil 0.03 mg/kg, BAY 60-4552 0.03 mg/kg or 0.3 mg/kg, or a BAY 60-4552 0.03 mg/kg plus vardenafil 0.03 mg/kg combination were evaluated in CN-crushed rats. RESULTS AND LIMITATIONS Bilateral CN crush injury followed by a 3-wk recovery period decreased erectile responses to ES CN by about 50%. In CN-crushed rats, IV vardenafil 0.03 mg/kg and BAY 60-4552 (0.03 or 0.3 mg/kg) increased erectile responses to ES CN to the same extent: Δ intracavernosal pressure/mean arterial pressure (ICP/MAP) at 10 Hz ES CN was 21±1% after vehicle, 25±3% (p<0.001) after vardenafil, and 26±5% and 27±5% after BAY 60-4552 0.03 mg/kg (p<0.01) and 0.3 mg/kg (p<0.001), respectively. The combination of vardenafil with BAY 60-4552 in CN-crushed rats totally restored erectile responses to ES CN equivalent to sham rats (ΔICP/MAP at 10 Hz ES CN: 34±4% after BAY 60-4552/vardenafil combination vs 39±4% in sham rats; not significant). CONCLUSIONS The present study supports the concept that the combined administration of a sGC stimulator, BAY 60-4552, and vardenafil provides synergistic beneficial effects and might therefore salvage patients who experience treatment failures with PDE5 inhibitors after RP.
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Affiliation(s)
- Johannes-Peter Stasch
- Institute of Pharmacy, Martin Luther University, Halle, and the Cardiology Research, Bayer HealthCare AG, Wuppertal, Germany.
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Albersen M, Shindel AW, Mwamukonda KB, Lue TF. The future is today: emerging drugs for the treatment of erectile dysfunction. Expert Opin Emerg Drugs 2010; 15:467-80. [PMID: 20415601 DOI: 10.1517/14728214.2010.480973] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
IMPORTANCE OF THE FIELD Erectile dysfunction (ED) is the most common male sexual dysfunction presented for treatment affecting between 10 and 20% of men. PDE type 5 inhibitors (PDE5I) now account for the largest segment of the ED market. While these drugs are highly efficacious for many men, a relatively large subset of ED patients who do not respond to PDE5I is increasingly recognized. AREAS COVERED IN THIS REVIEW In this review, we discuss clinical and preclinical evidence supporting various emerging compounds that regulate penile erection both centrally (clavulanic acid, dopamine and melanocortin receptor agonists) and peripherally (novel PDE5I, soluble and particulate guanylil cyclase activators, rho-kinase inhibitors and maxi-K channel openers). WHAT THE READER WILL GAIN The reader will gain a broad understanding of erectile (patho-)physiology and gain insights in the mechanisms of action, efficacy and adverse events of various compounds under development for the treatment of ED. TAKE HOME MESSAGE We expect emerging drugs to allow treatment protocols tailored to the specific needs of each individual patient, taking into consideration the efficacy of erectile performance enhancement and the potential for adverse events. This tailored approach may include combination of various emerging drugs to enhance efficacy in difficult-to-treat patients.
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Affiliation(s)
- Maarten Albersen
- Basic Research Fellow Male Sexual Dysfunction, University of California at San Francisco, Department of Urology, Knuppe Molecular Urology Laboratory, Campus Box 0738, San Francisco, CA 94143-0738, USA
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Claudino MA, da Silva FH, Mónica FZT, Rojas-Moscoso JA, De Nucci G, Antunes E. Long-term oral treatment with BAY 41-2272 ameliorates impaired corpus cavernosum relaxations in a nitric oxide-deficient rat model. BJU Int 2010; 108:116-22. [PMID: 20950311 DOI: 10.1111/j.1464-410x.2010.09776.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
OBJECTIVE • To investigate the potential beneficial effects of 4-week oral treatment with 5-cyclopropyl-2-[1-(2-fluoro-benzyl)-1Hpyrazolo[3,4-b]pyridin-3-yl]-pyrimidin-4-ylamine (BAY 41-2272), a nitric oxide (NO)-independent soluble guanylate cyclase activator, on impaired rat corpus cavernosum relaxations in NO-deficient rats. MATERIAL AND METHODS • Male Wistar rats were divided into four groups: Control, N (G)-nitro-L- arginine methyl ester (L-NAME; 20 mg/rat/day), BAY 41-2272 (20 mg/kg/day) and L-NAME + BAY 41-2272. • Rats were treated with L-NAME concomitantly with BAY 41-2272 for 4 weeks. • Concentration-response curves to acetylcholine (ACh) and sodium nitroprusside (SNP), along with the nitrergic relaxations (1-32 Hz) were obtained in rat corpus cavernosum (RaCC). • The RaCC contractile responses to the α₁ -adrenoceptor agonist phenylephrine (PE) were obtained. RESULTS • Acetylcholine (0.01-1000 µmol/L) produced concentration-dependent relaxing responses in RaCC that were significantly enhanced (P < 0.05) in BAY 41-2272-treated rats. • The ACh-induced relaxations were largely reduced in L-NAME-treated rats, and co-treatment with BAY 41-2272 failed to significantly modify these impaired relaxations. • The SNP-induced relaxations were modified neither by L-NAME nor by co-treatment with BAY 41-2272. • The nitrergic relaxations were significantly amplified in BAY 41-2272-treated rats (at 16 and 32 Hz). A significant reduction in the nitrergic relaxations was observed in L-NAME-treated rats, an effect largely restored by co-treatment with BAY 41-2272. • The contractile RaCC responses produced by PE (0.001-100 µmol/L) were significantly higher (P < 0.05) in L-NAME-treated rats, and co-treatment of L-NAME with BAY 41-2272 nearly restored these enhanced contractile responses. CONCLUSION • Four-week therapy with BAY 41-2272 prevents the impaired corpus cavernosum relaxations of rats treated chronically with L-NAME, indicating that accumulation of cyclic guanosine monophosphate into erectile tissue counteracts the NO deficiency.
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Affiliation(s)
- Mário A Claudino
- Department of Pharmacology, Faculty of Medical Sciences, University of Campinas (UNICAMP), Campinas (Sao Paulo), Brazil
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Abstract
Erectile dysfunction (ED) affects up to 50% of men between the ages of 40 and 70. Treatment with PDE-5 inhibitors is effective in the majority of men with ED. However, PDE-5 inhibitors are not effective when levels of nitric oxide (NO), the principle mediator of erection, are low. The pharmacologic actions of three new potential treatments for ED are discussed in this paper: (1) sGC stimulators/activators, (2) Rho-kinase inhibitors, and (3) sodium nitrite.
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Gur S, Kadowitz PJ, Hellstrom WJG. A critical appraisal of erectile function in animal models of diabetes mellitus. ACTA ACUST UNITED AC 2009; 32:93-114. [DOI: 10.1111/j.1365-2605.2008.00928.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Abstract
During the last decades it turned out that the NO/cGMP signaling cascade is one of the most prominent regulators of a variety of physiological and pathophysiological processes in a broad range of mammalian tissues. Thus cGMP is a key second messenger and targeting this pathway by increasing intracellular cGMP levels is a very successful approach in pharmacology as shown for nitrates, PDE5 inhibitors and more recently for stimulators of the guanylate cyclase. Besides the beneficial effects of cGMP elevation in cardiac, vascular, pulmonary, renal or liver disorders the launch of PDE5 inhibitors for the treatment of erectile dysfunction 10 years ago, has directed a lot of attention to the NO/cGMP signaling in the lower urinary tract. Triggered by the use of PDE5 inhibitors in ED it turned out that cGMP is a common regulatory mechanism for lower urinary tract function also beyond ED. In recent years intense research and development efforts were undertaken to elucidate the role of the NO/cGMP and to fully exploit the therapeutic implications of cGMP elevation in urological disorders in ED and beyond. Therefore we have summarized the effects of cGMP elevation for treatment of erectile dysfunction in males and in females. We have also reviewed the recent pre-clinical and clinical lines of evidence for treatment options of benign prostatic hyperplasia and lower urinary tract symptoms in male patients and overactive bladder and urinary incontinence in female patients. In addition we also touch more speculative concepts using cGMP elevating drugs for the treatment of premature ejaculation, peyornies disease and stone disease.
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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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Evgenov OV, Pacher P, Schmidt PM, Haskó G, Schmidt HHHW, Stasch JP. NO-independent stimulators and activators of soluble guanylate cyclase: discovery and therapeutic potential. Nat Rev Drug Discov 2006; 5:755-68. [PMID: 16955067 PMCID: PMC2225477 DOI: 10.1038/nrd2038] [Citation(s) in RCA: 533] [Impact Index Per Article: 29.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Soluble guanylate cyclase (sGC) is a key signal-transduction enzyme activated by nitric oxide (NO). Impaired bioavailability and/or responsiveness to endogenous NO has been implicated in the pathogenesis of cardiovascular and other diseases. Current therapies that involve the use of organic nitrates and other NO donors have limitations, including non-specific interactions of NO with various biomolecules, lack of response and the development of tolerance following prolonged administration. Compounds that activate sGC in an NO-independent manner might therefore provide considerable therapeutic advantages. Here we review the discovery, biochemistry, pharmacology and clinical potential of haem-dependent sGC stimulators (including YC-1, BAY 41-2272, BAY 41-8543, CFM-1571 and A-350619) and haem-independent sGC activators (including BAY 58-2667 and HMR-1766).
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Affiliation(s)
- Oleg V Evgenov
- Department of Anesthesia and Critical Care, Massachusetts General Hospital, Harvard Medical School, 55 Fruit Street, CLN 309, Boston, Massachusetts 02114, USA
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Burnett AL, Musicki B, Jin L, Bivalacqua TJ. Nitric oxide/redox-based signalling as a therapeutic target for penile disorders. Expert Opin Ther Targets 2006; 10:445-57. [PMID: 16706684 DOI: 10.1517/14728222.10.3.445] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Oxidative and/or nitrosative stress is implicated in the pathogeneses of assorted penile disorders of clinical significance, notably erectile dysfunction, priapism and penile fibrosis. It is becoming increasingly recognised that the generation and activity of reactive oxygen and nitrogen species in the penis influence vascular homeostasis of this organ, with adverse effects exerted at cellular and molecular levels. Furthermore, these elements may interact with molecular signalling pathways operating in the penis, modulating their functional roles. This interaction in particular suggests that by accessing molecular targets associated with oxidative/nitrosative stress in the penis, new pharmacotherapeutic approaches may be developed to promote normal erectile ability and preserve erectile tissue health. This notion pertains to, but also extends beyond, interventions which predictably target components of the nitric oxide-based signal transduction pathway for the on-demand treatment of erectile dysfunction. The next line of pharmaceuticals for disorders of the penis, in general, may well spawn from an integrative understanding of the complex regulatory interactions influenced by, as well as influencing nitric oxide signalling in this organ.
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Affiliation(s)
- Arthur L Burnett
- Department of Urology, The James Buchanan Brady Urological Institute, The Johns Hopkins University School of Medicine, Baltimore, MD 21287-2411, USA.
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Teixeira CE, Priviero FBM, Claudino MA, Baracat JS, De Nucci G, Webb RC, Antunes E. Stimulation of soluble guanylyl cyclase by BAY 41-2272 relaxes anococcygeus muscle: interaction with nitric oxide. Eur J Pharmacol 2005; 530:157-65. [PMID: 16371226 DOI: 10.1016/j.ejphar.2005.11.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2005] [Revised: 11/01/2005] [Accepted: 11/08/2005] [Indexed: 11/26/2022]
Abstract
The compound BAY 41-2272 stimulates the soluble guanylyl cyclase in a nitric oxide (NO)-independent manner. We have investigated the potency and efficacy of BAY 41-2272 in the rat anococcygeus muscle, as well as the effects of BAY 41-2272 on NO-mediated anococcygeus relaxations. BAY 41-2272 (0.01-10 microM) potently relaxed precontracted anococcygeus muscle strips, with a pEC(50) value of 6.44 +/- 0.03 and maximum response of 100 +/- 2%. The soluble guanylyl cyclase inhibitor 1H-[1,2,4]-oxidiazolo[4,3-a] quinoxalin-1-one (ODQ, 1 microM) and the NO inhibitor N(omega)-nitro-L-arginine methyl ester (L-NAME, 100 microM) caused significant rightward shifts in the concentration-response curves to BAY 41-2272. The phosphodiesterase type-5 inhibitor tadalafil (0.1 microM) markedly enhanced the relaxations evoked by BAY 41-2272. In addition, BAY 41-2272 increased the duration of nitrergic relaxations by approximately 55%. The relaxations induced by glyceryl trinitrate were also significantly potentiated by BAY 41-2272. In conclusion, BAY 41-2272 interacts with endogenous and exogenous NO causing a potent relaxation of rat anococcygeus muscle.
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Affiliation(s)
- Cleber E Teixeira
- Department of Pharmacology, Faculty of Medical Sciences, UNICAMP, Campinas (SP), Brazil
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Bischoff E, Stasch JP. Effects of the sGC stimulator BAY 41-2272 are not mediated by phosphodiesterase 5 inhibition. Circulation 2005; 110:e320-1; author reply e320-1. [PMID: 15381669 DOI: 10.1161/01.cir.0000142209.28862.12] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Kalsi JS, Ralph DJ, Thomas P, Bellringer J, Minhas S, Kell PD, Cellek S. ORIGINAL RESEARCH—BASIC SCIENCE: A Nitric Oxide‐Releasing PDE5 Inhibitor Relaxes Human Corpus Cavernosum in the Absence of Endogenous Nitric Oxide. J Sex Med 2005; 2:53-7. [PMID: 16422907 DOI: 10.1111/j.1743-6109.2005.20105.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
INTRODUCTION In conditions with severe deficiency of endogenous nitric oxide (NO), such as long-term diabetes and cavernosal nerve injury, phosphodiesterase type 5 (PDE5) inhibitors have reduced efficacy in the treatment of erectile dysfunction. NO-releasing PDE5 inhibitors could be an alternative therapeutic approach in such cases. AIM We therefore aimed to compare sildenafil and NO-releasing sildenafil (NCX-911) in relaxing human corpus cavernosum in the absence or presence of endogenous NO. METHODS The two compounds were compared in reducing the phenylephrine-induced tone of human corpus cavernosum in the presence or absence of an inhibitor of NO synthase (L-NAME; 500 microM) or an inhibitor of soluble guanylate cyclase (ODQ, 10 microM). RESULTS NCX-911 was as potent as sildenafil in control conditions (EC(50) = 733.1 +/- 94.4 nM and 800.7 +/- 155.8 nM, respectively). The potency of NCX-911 was not altered but that of sildenafil decreased significantly in the presence of L-NAME (EC(50) = 980.4 +/- 106.7 nM and 2446.7 +/- 256.8 nM, respectively; P < 0.001 for sildenafil vs. control). Both compounds below 1 microM failed to induce relaxation in the presence of ODQ (EC(50) = 6,578 +/- 1150 nM and 6,488 +/- 938 nM for NCX-911 and sildenafil, respectively). CONCLUSION These results show that the potency of NCX-911 was maintained unlike sildenafil in the absence of endogenous NO confirming the potential use of NO-releasing PDE5 inhibitors in NO-deficient conditions.
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Affiliation(s)
- Jasjit S Kalsi
- The St. Peter's Andrology Centre and Wolfson Institute for Biomedical Research, University College London, UK
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