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Navarro-Dorado J, Climent B, López-Oliva ME, Pilar Martínez M, Hernández-Martín M, Agis-Torres Á, Recio P, Victoria Barahona M, Benedito S, Fernandes VS, Hernández M. The bitter taste receptor (TAS2R) agonist denatonium promotes a strong relaxation of rat corpus cavernosum. Biochem Pharmacol 2023; 215:115754. [PMID: 37597814 DOI: 10.1016/j.bcp.2023.115754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 08/15/2023] [Accepted: 08/16/2023] [Indexed: 08/21/2023]
Abstract
Bitter taste receptors (TAS2R) are found in numerous extra-oral tissues, including smooth muscle (SM) cells in both vascular and visceral tissues. Upon activation, TAS2R stimulate the relaxation of the SM. Nitric oxide (NO)/cyclic guanosine monophosphate (cGMP) signaling pathway is involved in penile erection, and type 5 phosphodiesterase (PDE5) inhibitors, a cGMP-specific hydrolase are used as first-line treatments for erectile dysfunction (ED). Nevertheless, PDE5 inhibitors are ineffective in a considerable number of patients, prompting research into alternative pharmacological targets for ED. Since TAS2R agonists regulate SM contractility, this study investigates the role of TAS2Rs in rat corpus cavernosum (CC). We performed immunohistochemistry to detect TAS2R10, isometric force recordings for TAS2R agonists denatonium and chloroquine, the slow-release H2S donor GYY 4137, the NO donor SNAP, the β-adrenoceptor agonist isoproterenol and electrical field stimulation (EFS), as well as measurement of endogenous hydrogen sulfide (H2S) production. The immunofluorescence staining indicated that TAS2R10 was broadly expressed in the CC SM and to some extent in the nerve fibers. Denatonium, chloroquine, SNAP, and isoproterenol cause potent dose-dependent SM relaxations. H2S production was decreased by NO and H2S synthase inhibitors, while it was enhanced by denatonium. In addition, denatonium increased the relaxations induced by GYY 4137 and SNAP but failed to modify EFS- and isoproterenol-induced responses. These results suggest neuronal and SM TAS2R10 expression in the rat CC, where denatonium induces a strong SM relaxation per se and promotes the H2S- and NO-mediated inhibitory gaseous neurotransmission. Thus, TAS2R10 might represent a valuable therapeutic target in ED.
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Affiliation(s)
- Jorge Navarro-Dorado
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense de Madrid, 28040-Madrid, Spain
| | - Belén Climent
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense de Madrid, 28040-Madrid, Spain
| | - María Elvira López-Oliva
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense de Madrid, 28040-Madrid, Spain
| | - María Pilar Martínez
- Departamento de Anatomía y Embriología, Facultad de Veterinaria, Universidad Complutense de Madrid, 28040-Madrid, Spain
| | - Marina Hernández-Martín
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense de Madrid, 28040-Madrid, Spain
| | - Ángel Agis-Torres
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense de Madrid, 28040-Madrid, Spain
| | - Paz Recio
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense de Madrid, 28040-Madrid, Spain
| | - María Victoria Barahona
- Departamento de Farmacología y Toxicología, Facultad de Veterinaria, Universidad Complutense de Madrid, 28040-Madrid, Spain
| | - Sara Benedito
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense de Madrid, 28040-Madrid, Spain
| | - Vítor S Fernandes
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense de Madrid, 28040-Madrid, Spain.
| | - Medardo Hernández
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense de Madrid, 28040-Madrid, Spain.
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Fernandes VS, López-Oliva ME, Martínez MP, Agis-Torres Á, Recio P, Navarro-Dorado J, Barahona MV, Benedito S, Prieto D, Climent B, Hernández M. In vitro inhibition of phosphodiesterase type 4 enhances rat corpus cavernosum nerve-mediated relaxation induced by gasotransmitters. Life Sci 2022; 296:120432. [PMID: 35219697 DOI: 10.1016/j.lfs.2022.120432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 02/16/2022] [Accepted: 02/21/2022] [Indexed: 11/15/2022]
Abstract
AIMS Nitric oxide (NO) and hydrogen sulfide (H2S) are involved in nerve-mediated corpus cavernosum (CC) relaxation. Expression of phosphodiesterase type 5 (PDE5) and type 4 (PDE4), cyclic guanosine monophosphate (cGMP)- and cyclic adenosine monophosphate (cAMP)-specific, respectively, has been described and PDE5- and PDE4-inhibitors induce cavernous smooth muscle relaxation. Whereas the NO/cGMP signaling pathway is well established in penile erection, the cAMP-mediated mechanism is not fully elucidated. The aim of this study is to investigate the localization and the functional significance of PDE4 in rat CC tone regulation. MAIN METHODS We performed immunohistochemistry for the detection of the PDE4A isoenzyme. Isometric tension recordings for roflumilast and tadalafil, PDE4 and PDE5 inhibitors, respectively, electrical field stimulation (EFS) and β-adrenoceptor agonist isoproterenol and endogenous H2S production measurement. KEY FINDINGS A marked PDE4A expression was detected mainly localized in the nerve cells of the cavernous smooth muscle. Furthermore, roflumilast and tadalafil exhibited strong corpus cavernous relaxations. Endogenous H2S production was decreased by NO and H2S synthase inhibitors and increased by roflumilast. Isoproterenol- and EFS-induced relaxations were increased by roflumilast. SIGNIFICANCE These results indicate that PDE4A is mainly expressed within the nerves cells of the rat CC, where roflumilast induces a potent corpus cavernous relaxation per se and potentiates the response induced by β-adrenoceptor activation. The fact that roflumilast enhances H2S production, as well as EFS-elicited responses suggests that PDE4 inhibitors modulate, in a positive feedback fashion, nerve-mediated relaxation induced by gasotransmitters, thus indicating a key role for neuronal PDE4 in penile erection.
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Affiliation(s)
- Vítor S Fernandes
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - María Elvira López-Oliva
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - María Pilar Martínez
- Departamento de Anatomía y Anatomía Patológica Comparadas, Facultad de Veterinaria, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Ángel Agis-Torres
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Paz Recio
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Jorge Navarro-Dorado
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - María Victoria Barahona
- Departamento de Farmacología y Toxicología, Facultad de Veterinaria, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Sara Benedito
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Dolores Prieto
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - Belén Climent
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense de Madrid, 28040 Madrid, Spain.
| | - Medardo Hernández
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense de Madrid, 28040 Madrid, Spain.
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de Oliveira MG, Rojas-Moscoso JA, Bertollotto GM, Candido TZ, Kiguti LRDA, Pupo AS, Antunes E, De Nucci G, Mónica FZ. Mirabegron elicits rat corpus cavernosum relaxation and increases in vivo erectile response. Eur J Pharmacol 2019; 858:172447. [PMID: 31228454 DOI: 10.1016/j.ejphar.2019.172447] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Revised: 06/06/2019] [Accepted: 06/12/2019] [Indexed: 12/18/2022]
Abstract
Mirabegron is the first β3-adrenoceptor agonist approved on the market and may offer beneficial pharmacological action in patients with overactive bladder and erectile dysfunction. Here, we further investigate the mechanisms by which mirabegron induces rat corpus cavernosum (CC) relaxation. Adult male Wistar rats were used. The CC were isolated for in vitro functional assays and β-adrenoceptors subtypes mRNA expression evaluation. Animals were treated orally with mirabegron (30 mg/kg, 3 h), tadalafil (10 mg/kg, 3 h) or both for intracavernous pressure (ICP). Intracellular levels of cAMP and cGMP were also determined. The β1-, β2- and β3-adrenoceptors subtypes were expressed in rat CC. Mirabegron produced concentration-dependent CC relaxations that were unaffected by the β1-, β2- or β3-adrenoceptor antagonists atenolol (1 μM), ICI-118,551 (1 μM) and L748,337 (10 μM), respectively. Mirabegron-induced relaxations were not affected by the phosphodiesterase type 4 inhibitor, rolipram, or the adenylyl cyclase selective inhibitor, SQ 22,536. Potassium channel- or calcium influx-blockade are not involved in mirabegron-induced relaxations. In contrast, mirabegron produced rightward shifts in the contractile response induced by the α1-adrenoceptor agonist, phenylephrine. Finally, cavernous nerve stimulation caused frequency-dependent ICP increases, which were significantly increased in rats treated with mirabegron in a similar degree of tadalafil-treated rat, without promoting a significant cAMP or cGMP accumulation. Together, our results demonstrate that mirabegron induced CC relaxation through α1-adrenoceptor blockade. Care should be taken to translate the effect of mirabegron into the clinic, especially when using rat as an animal model of erectile dysfunction.
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Affiliation(s)
- Mariana G de Oliveira
- Department of Pharmacology, Faculty of Medical Sciences, University of Campinas (UNICAMP), Brazil.
| | | | - Gabriela M Bertollotto
- Department of Pharmacology, Faculty of Medical Sciences, University of Campinas (UNICAMP), Brazil
| | - Tuany Z Candido
- Department of Pharmacology, Faculty of Medical Sciences, University of Campinas (UNICAMP), Brazil
| | - Luiz Ricardo de A Kiguti
- Department of Pharmacology, Faculty of Medical Sciences, University of Campinas (UNICAMP), Brazil
| | - André S Pupo
- Department of Pharmacology, Institute of Biosciences, São Paulo State University (UNESP), Brazil
| | - Edson Antunes
- Department of Pharmacology, Faculty of Medical Sciences, University of Campinas (UNICAMP), Brazil
| | - Gilberto De Nucci
- Department of Pharmacology, Faculty of Medical Sciences, University of Campinas (UNICAMP), Brazil
| | - Fabíola Z Mónica
- Department of Pharmacology, Faculty of Medical Sciences, University of Campinas (UNICAMP), Brazil
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Aydın K, Gökçen K, Yıldırım Ş, Bagcivan İ, Parlak M, Gökçe G. In vitro evaluation of nebivolol effects on nonadrenergic noncholinergic responses in rabbit corpus cavernosum. Andrologia 2018; 50:e13062. [PMID: 29920739 DOI: 10.1111/and.13062] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2018] [Revised: 04/30/2018] [Accepted: 05/03/2018] [Indexed: 12/01/2022] Open
Abstract
The purpose of this study was to compare the effects of nebivolol on nonadrenergic noncholinergic (NANC) relaxation functions that are mediated by electric field stimulation (EFS) in rabbit corpus cavernosum smooth muscle by comparison with other beta-adrenergic receptor blockers and show the level on which its effects through nitric oxide take place. After the effects of nebivolol on the isolated corpus cavernosum tissues that were contracted through the alpha-adrenergic pathway and application of L-NAME' (NG -nitro-L-arginine methyl ester) which is a competitive inhibitor of nitric oxide synthase (NOS), the changes that occurred were recorded. Following the effect on the tissue that was contracted with phenylephrine in the presence of atropine and guanethidine that was created by EFS, nebivolol and other beta-blockers were added and the changes were recorded. After receiving relaxation responses with EFS-mediated NANC, no difference was observed between the relaxation responses due to addition of nebivolol and other beta-adrenergic blockers (p > 0.05). The finding that nebivolol which has a NO-mediated relaxation effect did not have an effect on EFS-mediated NANC relaxation but created relaxation on the tissue that was contracted by phenylephrine and the effect was reversed by L-NAME, shows that its effects are on a postsynaptic level.
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Affiliation(s)
- Kaya Aydın
- Department of Pharmacology, School of Medicine, Cumhuriyet University, Sivas, Turkey
| | - Kaan Gökçen
- Department of Urology, School of Medicine, Cumhuriyet University, Sivas, Turkey
| | - Şahin Yıldırım
- Department of Pharmacology, School of Medicine, Cumhuriyet University, Sivas, Turkey
| | - İhsan Bagcivan
- Department of Pharmacology, School of Medicine, Cumhuriyet University, Sivas, Turkey
| | - Mesut Parlak
- Department of Pharmacology, School of Medicine, Cumhuriyet University, Sivas, Turkey
| | - Gökhan Gökçe
- Department of Urology, School of Medicine, Cumhuriyet University, Sivas, Turkey
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Gur S, Peak T, Yafi FA, Kadowitz PJ, Sikka SC, Hellstrom WJ. Mirabegron causes relaxation of human and rat corpus cavernosum: could it be a potential therapy for erectile dysfunction? BJU Int 2016; 118:464-74. [DOI: 10.1111/bju.13515] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Serap Gur
- Department of Pharmacology; School of Pharmacy; Ankara University; Ankara Turkey
- Department of Urology; Tulane University Health Sciences Center; New Orleans LA USA
| | - Taylor Peak
- Department of Urology; Tulane University Health Sciences Center; New Orleans LA USA
| | - Faysal A. Yafi
- Department of Urology; Tulane University Health Sciences Center; New Orleans LA USA
| | - Philip J. Kadowitz
- Department of Pharmacology; Tulane University Health Sciences Center; New Orleans LA USA
| | - Suresh C. Sikka
- Department of Urology; Tulane University Health Sciences Center; New Orleans LA USA
| | - Wayne J.G. Hellstrom
- Department of Urology; Tulane University Health Sciences Center; New Orleans LA USA
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Gagliano-Jucá T, Napolitano M, Del Grossi Ferraz Carvalho F, Campos R, Mónica FZ, Claudino MA, Antunes E, Lopes AG, De Nucci G. Hydrochlorothiazide Potentiates Contractile Activity of Mouse Cavernosal Smooth Muscle. Sex Med 2016; 4:e113-23. [PMID: 27006319 PMCID: PMC5005312 DOI: 10.1016/j.esxm.2016.02.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Revised: 02/04/2016] [Accepted: 02/21/2016] [Indexed: 11/24/2022] Open
Abstract
Introduction Hydrochlorothiazide has a negative influence on penile erection but little is known about the mechanism(s) involved. Aims To characterize the effects of this diuretic on mouse corpus cavernosum (CC) smooth muscle in vitro and ex vivo. Methods CC strips of C57BL/6 mice (12–16 weeks old) were mounted in organ baths containing Krebs-Henseleit solution and tissue reactivity was evaluated. Expression of genes encoding diuretic targets and enzymes involved in penile erection were evaluated by polymerase chain reaction. Main Outcome Measures Stimulation-response curves to phenylephrine (10 nmol/L–100 μmol/L) or to electrical field stimulation (1–32 Hz) were constructed, with or without hydrochlorothiazide. Strips of CC from mice after long-term hydrochlorothiazide treatment (6 mg/kg/day for 4 weeks) with or without amiloride (0.6 mg/kg/day for 4 weeks) in vivo also were studied. Nitric oxide and Rho-kinase pathways were evaluated. Results Hydrochlorothiazide (100 μmol/L) increased the maximum response to phenylephrine by 64% in vitro. This effect was unaffected by the addition of indomethacin (5 μmol/L) but was abolished by N(ω)-nitro-L-arginine methyl ester (100 μmol/L). Hydrochlorothiazide (100 μmol/L) potentiated electrical field stimulation-induced contraction in vitro, but not ex vivo. Long-term treatment with hydrochlorothiazide increased the maximum response to phenylephrine by 60% and resulted in a plasma concentration of 500 ± 180 nmol/L. Amiloride (100μmol/L) caused rightward shifts in concentration-response curves to phenylephrine in vitro. Long-term treatment with hydrochlorothiazide plus amiloride did not significantly increase the maximum response to phenylephrine (+13%). Reverse transcriptase polymerase chain reaction did not detect the NaCl cotransporter in mouse CC. Hydrochlorothiazide did not change Rho-kinase activity, whereas amiloride decreased it in vitro and ex vivo (approximately 18% and 24% respectively). A 40% decrease in Rock1 expression also was observed after long-term treatment with hydrochlorothiazide plus amiloride. Conclusion Hydrochlorothiazide potentiates contraction of smooth muscle from mouse CC. These findings could explain why diuretics such as hydrochlorothiazide are associated with erectile dysfunction.
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Affiliation(s)
- Thiago Gagliano-Jucá
- Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, Brazil
| | - Mauro Napolitano
- Department of Pharmacology, Institute of Biomedical Sciences, University of Sao Paulo (USP), Sao Paulo, SP, Brazil.
| | | | - Rafael Campos
- Department of Pharmacology, Faculty of Medical Sciences, State University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Fabíola Zakia Mónica
- Department of Pharmacology, Faculty of Medical Sciences, State University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Mário Angelo Claudino
- Department of Pharmacology, Faculty of Medical Sciences, State University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Edson Antunes
- Department of Pharmacology, Faculty of Medical Sciences, State University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Anibal Gil Lopes
- Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, Brazil
| | - Gilberto De Nucci
- Department of Pharmacology, Institute of Biomedical Sciences, University of Sao Paulo (USP), Sao Paulo, SP, Brazil; Department of Pharmacology, Faculty of Medical Sciences, State University of Campinas (UNICAMP), Campinas, SP, Brazil
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Hothersall JD, Black J, Caddick S, Vinter JG, Tinker A, Baker JR. The design, synthesis and pharmacological characterization of novel β₂-adrenoceptor antagonists. Br J Pharmacol 2012; 164:317-31. [PMID: 21323900 DOI: 10.1111/j.1476-5381.2011.01269.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND AND PURPOSE Selective and potent antagonists for the β(2) -adrenoceptor are potentially interesting as experimental and clinical tools, and we sought to identify novel ligands with this pharmacology. EXPERIMENTAL APPROACH A range of pharmacological assays was used to assess potency, affinity, selectivity (β(2) -adrenoceptor vs. β(1) -adrenoceptor) and efficacy. KEY RESULTS Ten novel compounds were identified but none had as high affinity as the prototypical β(2) -adrenoceptor blocker ICI-118,551, although one of the novel compounds was more selective for β(2) -adrenoceptors. Most of the ligands were inverse agonists for β(2) -adrenoceptor-cAMP signalling, although one (5217377) was a partial agonist and another a neutral antagonist (7929193). None of the ligands were efficacious with regard to β(2) -adrenoceptor-β-arrestin signalling. The (2S,3S) enantiomers were identified as the most active, although unusually the racemates were the most selective for the β(2) -adrenoceptors. This was taken as evidence for some unusual enantiospecific behaviour. CONCLUSIONS AND IMPLICATIONS In terms of improving on the pharmacology of the ligand ICI-118,551, one of the compounds was more selective (racemic JB-175), while one was a neutral antagonist (7929193), although none had as high an affinity. The results substantiate the notion that β-blockers do more than simply inhibit receptor activation, and differences between the ligands could provide useful tools to investigate receptor biology.
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Kam SC, Do JM, Choi JH, Jeon BT, Roh GS, Chang KC, Hyun JS. The relaxation effect and mechanism of action of higenamine in the rat corpus cavernosum. Int J Impot Res 2011; 24:77-83. [PMID: 21956762 DOI: 10.1038/ijir.2011.48] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Higenamine mediates cardiotonic, vascular relaxation and bronchodilator effects. The relaxation effects and the mechanism of action of higenamine on the rat corpus cavernosum (CC) were assessed to investigate the effect of higenamine on penile erection. Strips of CC and aorta were used in organ baths for isometric tension studies. Tension was measured with isometric force transducers, and muscle relaxation was expressed as the percent decrease in precontraction induced by phenylephrine (PE). The relaxation reactions were investigated in an endothelial-denuded group and groups pretreated with N(G)-nitro-L-arginine methyl ester (NO synthesis inhibitor), propranolol (β-receptor blocker), indomethacin (COX inhibitor), glibenclamide (K(+)(ATP) channel inhibitor), 4-aminopyridine (membrane potential-dependent potassium channel inhibitor) and methylene blue (guanylyl cyclase inhibitor) for 30 min. Intracavernous pressure (ICP) was assessed in rats after the intravenous administration of higenamine, and changes in guanosine 3',5'-cyclic monophosphate and adenosine 3',5'-cyclic monophosphate (cAMP) concentrations were measured on the basis of the higenamine concentration. Also, the combined reaction of higenamine and the phosphodiesterase type-5 (PDE-5) inhibitors was assessed. Higenamine induced relaxation of the CC and the aortic strips precontracted with PE in a dose-dependent manner. The CC was significantly more relaxed than the aortic rings in response to the same higenamine concentration (P<0.05). The CC relaxation reaction was suppressed by the β-receptor blocker propranolol. The cAMP concentration increased gradually with increased higenamine concentration (P<0.05). The ICP also increased with increased higenamine concentration in vivo (P<0.05). In the group pretreated with 10(-7) M higenamine, the relaxation reaction of CC induced by the PDE-5 inhibitor increased significantly, compared with CC exposed to the PDE-5 inhibitor but not pretreated with higenamine (P<0.05). In conclusion, higenamine induced relaxation of the rat CC in a dose-dependent manner. The effect may be mediated through β-adrenoceptors. The results suggest that higenamine may be valuable as a new lead compound for treating erectile dysfunction.
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Affiliation(s)
- S C Kam
- Department of Urology, Institute of Health Sciences, Gyeongsang National University School of Medicine, Jinju, Korea
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Capel RO, Mónica FZ, Porto M, Barillas S, Muscará MN, Teixeira SA, Arruda AMM, Pissinatti L, Pissinatti A, Schenka AA, Antunes E, Nahoum C, Cogo JC, de Oliveira MA, De Nucci G. Role of a novel tetrodotoxin-resistant sodium channel in the nitrergic relaxation of corpus cavernosum from the South American rattlesnake Crotalus durissus terrificus. J Sex Med 2011; 8:1616-25. [PMID: 21477017 DOI: 10.1111/j.1743-6109.2011.02246.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
INTRODUCTION Coitus in snakes may last up to 28 hours; however, the mechanisms involved are unknown. AIM To evaluate the relevance of the nitric oxide (NO)-cyclic guanosine monophosphate (cGMP)-phosphodiesterase type 5 (PDE5) system in snake corpus cavernosum reactivity. METHODS Hemipenes were removed from anesthetized South American rattlesnakes (Crotalus durissus terrificus) and studied by light and scanning electronic microscopy. Isolated Crotalus corpora cavernosa (CCC) were dissected from the non-spiny region of the hemipenises, and tissue reactivity was assessed in organ baths. MAIN OUTCOME MEASURES Cumulative concentration-response curves were constructed for acetylcholine (ACh), sodium nitroprusside (SNP), 5-cyclopropyl-2-[1-(2-fluorobenzyl)-1H-pyrazolo[3,4-b]pyridine-3-yl]pyrimidin-4-ylamine (BAY 41-2272), and tadalafil in CCC precontracted with phenylephrine. Relaxation induced by electrical field stimulation (EFS) was also done in the absence and presence of N(ω) nitro-L-arginine methyl ester (L-NAME; 100 µM), 1H-[1, 2, 4] oxadiazolo[4,3-a]quinoxalin-1-one (ODQ; 10 µM) and tetrodotoxin (TTX; 1 µM). RESULTS The hemipenes consisted of two functionally concentric corpora cavernosa, one of them containing radiating bundles of smooth muscle fibers (confirmed by α-actin immunostaining). Endothelial and neural nitric oxide synthases were present in the endothelium and neural structures, respectively; whereas soluble guanylate cyclase and PDE5 were expressed in trabecular smooth muscle. ACh and SNP relaxed isolated CCC, with the relaxations being markedly reduced by L-NAME and ODQ, respectively. BAY 41-2272 and tadalafil caused sustained relaxations with potency (pEC(50) ) values of 5.84 ± 0.17 and 5.10 ± 0.08 (N=3-4), respectively. In precontracted CCC, EFS caused frequency-dependent relaxations that lasted three times longer than those in mammalian CC. Although these relaxations were almost abolished by either L-NAME or ODQ, they were unaffected by TTX. In contrast, EFS-induced relaxations in marmoset CC were abolished by TTX. CONCLUSIONS Rattlesnake CC relaxation is mediated by the NO-cGMP-PDE5 pathway in a manner similar to mammals. The novel TTX-resistant Na channel identified here may be responsible for the slow response of smooth muscle following nerve stimulation and could explain the extraordinary duration of snake coitus.
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Affiliation(s)
- Rodrigo O Capel
- Department of Pharmacology, Faculty of Medical Sciences, State University of Campinas (UNICAMP), Campinas, SP, Brazil
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Abdel-Hamid IA, Andersson KE, Salonia A. Exploration of therapeutic targets for sexual dysfunctions: lessons learned from the failed stories. Expert Opin Ther Targets 2011; 15:325-40. [DOI: 10.1517/14728222.2011.551008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Claudino MA, Franco-Penteado CF, Corat MAF, Gimenes AP, Passos LAC, Antunes E, Costa FF. Increased cavernosal relaxations in sickle cell mice priapism are associated with alterations in the NO-cGMP signaling pathway. J Sex Med 2009; 6:2187-96. [PMID: 19493282 DOI: 10.1111/j.1743-6109.2009.01337.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
INTRODUCTION Priapism is defined as prolonged and persistent penile erection, unassociated with sexual interest or stimulation, and is one of the many serious complications associated with sickle cell disease (SCD). AIM The aim of this study was to evaluate the role of the NO-cGMP signaling pathway in priapism in Berkeley murine model of SCD (SS). METHODS SS mice and C57BL/6 mice (control) penile tissues were removed and the erectile tissue within the corpus cavernosum (CC) was surgically dissected free. The strips were mounted in 10 mL organ baths containing Krebs solution at 37 degrees C (95% O(2), 5% CO(2), pH 7.4), and vertically suspended between two metal hooks. MAIN OUTCOME MEASURES Cumulative concentration-response curves were constructed for acetylcholine (ACh; endothelium-dependent responses), sodium nitroprusside (SNP; endothelium-independent relaxations) and BAY 41-2272 (a potent activator of NO-independent site of soluble guanylate cyclase) in CC precontracted with phenylephrine. Cavernosal responses induced by frequency-dependent electrical field stimulation (EFS) were also carried out to evaluate the nitrergic cavernosal relaxations. RESULTS In SS mice, ACh-induced cavernosal relaxations were leftward shifted by 2.6-fold (P < 0.01) that was accompanied by increases in the maximal responses (78 +/- 5% and 60 +/- 3% in SS and C57B6/6J mice, respectively). Similarly, SNP- and BAY 41-2272-induced CC relaxations were leftward shifted by approximately 3.3- and 2.2-fold (P < 0.01) in SS mice, respectively. A significant increase in maximal responses to SNP and BAY 41-2272 in SS mice was also observed (113 +/- 6% and 124 +/- 5%, respectively) compared with C57B6/6J mice (83 +/- 4% and 99 +/- 2%, respectively). The EFS-induced cavernosal relaxations were also significantly higher SS mice. CONCLUSION These results showed that SS mice exhibit amplified corpus carvenosum relaxation response mediated by NO-cGMP signaling pathway. Intervention in this signaling pathway may be a potential therapeutic target to treat SCD priapism.
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Affiliation(s)
- Mário Angelo Claudino
- Department of Pharmacology, Faculty of Medical Sciences University of Campinas, Campinas, São Paulo, Brazil.
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Metabolic responses to BRL37344 and clenbuterol in soleus muscle and C2C12 cells via different atypical pharmacologies and beta2-adrenoceptor mechanisms. Br J Pharmacol 2008; 155:395-406. [PMID: 18552870 DOI: 10.1038/bjp.2008.244] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND AND PURPOSE Picomolar concentrations of the beta3-adrenoceptor agonist BRL37344 stimulate 2-deoxyglucose uptake in soleus muscle via undefined receptors. Higher concentrations alter uptake, apparently via beta2-adrenoceptors. Effects of BRL37344 and beta2-adrenoceptor agonists are compared. EXPERIMENTAL APPROACH Mouse soleus muscles were incubated with 2-deoxy[1-(14)C]-glucose, [1-(14)C]-palmitate or [2-(14)C]-pyruvate, and BRL37344, beta2-adrenoceptor agonists and selective beta-adrenoceptor antagonists. Formation of 2-deoxy[1-(14)C]-glucose-6-phosphate or (14)CO2 was measured. 2-Deoxy[1-(14)C]-glucose uptake and beta-adrenoceptor mRNA were measured in C2C12 cells. KEY RESULTS 10 pM BRL37344, 10 pM clenbuterol and 100 pM salbutamol stimulated 2-deoxyglucose uptake in soleus muscle by 33-54%. The effect of BRL37344 was prevented by 1 microM atenolol but not by 300 nM CGP20712A or IC3118551, or 1 microM SR59230A; that of clenbuterol was prevented by ICI118551 but not atenolol. 10 nM BRL37344 stimulated 2-deoxyglucose uptake, whereas 100 nM clenbuterol and salbutamol inhibited uptake. These effects were blocked by ICI118551. Similar results were obtained in C2C12 cells, in which only beta2-adrenoceptor mRNA could be detected by RT-PCR. 10 nM BRL37344 and 10 pM clenbuterol stimulated muscle palmitate oxidation. In the presence of palmitate, BRL37344 no longer stimulated 2-deoxyglucose uptake and the effect of clenbuterol was not significant. CONCLUSIONS AND IMPLICATIONS Stimulation of glucose uptake by 10 pM BRL37344 and clenbuterol involves different atypical pharmacologies. Nanomolar concentrations of BRL37344 and clenbuterol, probably acting via beta2-adrenoceptors, have opposite effects on glucose uptake. The agonists preferentially stimulate fat rather than carbohydrate oxidation, but stimulation of endogenous fat oxidation cannot explain why 100 nM clenbuterol inhibited 2-deoxyglucose uptake.
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Flores Toque HA, Priviero FBM, Teixeira CE, Perissutti E, Fiorino F, Severino B, Frecentese F, Lorenzetti R, Baracat JS, Santagada V, Caliendo G, Antunes E, De Nucci G. Synthesis and pharmacological evaluations of sildenafil analogues for treatment of erectile dysfunction. J Med Chem 2008; 51:2807-15. [PMID: 18393409 DOI: 10.1021/jm701400r] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The 5-[2-ethoxy-5-(4-methylpiperazin-1-ylsulfonyl)phenyl]-1-methyl-3-propyl-1,6-dihydro-7 H-pyrazolo[4,3-d]pyrimidin-7-one, sildenafil, is a cGMP-specific phosphodiesterase-5 (PDE5) inhibitor used for penile erectile dysfunction. In the search for more potent and selective PDE5 inhibitors, new sildenafil analogues (6a-v), characterized by the presence on the sulfonyl group in the 5' position of novel N-4-substituted piperazines or ethylenediamine moiety, were prepared by traditional and microwave-assisted synthesis and tested in rabbit isolated aorta and corpus cavernosum. Similarly to sildenafil, several analogues showed IC50 values in the nanomolar range. In the in vitro studies, all the tested compounds caused concentration-dependent relaxations in both rabbit isolated aorta and corpus cavernosum. All sildenafil analogues potentiated the nitric oxide-dependent vasodilation in endothelium-intact rabbit aorta. Compound 6f exhibited great pEC50 value in corpus cavernosum, and compounds 6r and 6u in isolated aorta were found as potent as sildenafil for inhibiting PDE5. Because several analogues were significantly more lipophilic than sildenafil, these compounds may offer a new lead for development of new sildenafil analogues.
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Affiliation(s)
- Haroldo A Flores Toque
- Department of Pharmacology, Faculty of Medical Sciences, State University of Campinas, Campinas, Brazil
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Grotthus B, Piasecki T, Pieśniewska M, Marszalik P, Kwiatkowska J, Skrzypiec-Spring M, Szelag A. The Influence of prolonged β-blockers treatment on male rabbit's sexual behavior and penile microcirculation. Int J Impot Res 2006; 19:49-54. [PMID: 16688208 DOI: 10.1038/sj.ijir.3901485] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The aim of the study was to assess the effect of the prolonged intake of three beta-blocking drugs (propranolol, metoprolol and nebivolol) on the sexual behavior and penile microcirculation of rabbits. Drugs were administered p.o. for 9 weeks and every three weeks in each group (n=13) one subgroup (n=7) performed behavioral tests, whereas in the second subgroup (n=6) penile microcirculation was measured with a laser Doppler flowmeter. The copulation studies revealed significant impairment of sexual function only in the propranolol treated group. The measured behavioral parameters suggest that at a given dose propranolol affects more performance rather than arousal aspects of rabbits' sexual behavior. In the course of the whole study no significant difference was observed among groups in penile blood flow. The data indicate that among the beta-blockers given only propranolol interferes with sexual behavior, and that beta-blockers do not appear to have a negative effect on penile microcirculation.
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Affiliation(s)
- B Grotthus
- Department of Pharmacology, Wrocław Medical University, Wrocław, Poland.
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Teixeira CE, Ying Z, Webb RC. Proerectile effects of the Rho-kinase inhibitor (S)-(+)-2-methyl-1-[(4-methyl-5-isoquinolinyl)sulfonyl]homopiperazine (H-1152) in the rat penis. J Pharmacol Exp Ther 2005; 315:155-62. [PMID: 15976017 DOI: 10.1124/jpet.105.086041] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The Rho-kinase pathway mediates Ca2+ sensitization in the penile circulation, which maintains the penis in the flaccid state. We aimed to investigate the functional effect of a novel Rho-kinase inhibitor, H-1152 [(S)-(+)-2-methyl-1-[(4-methyl-5-isoquinolinyl)sulfonyl]homopiperazine], both in vitro and in vivo as well as to demonstrate the expression of Rho guanine nucleotide exchange factors (RhoGEFs) in the rat corpus cavernosum (CC), by using a semiquantitative reverse transcription-polymerase chain reaction assay to measure their mRNA expression. Cumulative addition of H-1152 (0.001-3 microM) or Y-27632 [0.01-30 microM; (R)-(+)-trans-N-(4-pyridyl)-4-(1-aminoethyl)-cyclohexanecarboxamide] caused sustained relaxations of precontracted CC strips, which were not affected by inhibition of the nitric oxide signaling pathway. Addition of H-1152 (0.1 microM), Y-27632 (1 microM), or sodium nitroprusside (SNP; 0.1 microM) caused rightward shifts in the curves to phenylephrine (PE), but it had little effect on the contractions mediated by electrical field stimulation (EFS). It is noteworthy that when H-1152 or Y-27632 was combined with SNP, a marked synergistic inhibition was noted both on PE- and EFS-induced contractions. Intraperitoneal administration of H-1152 (100 nmol/kg) had a discrete effect on mean arterial pressure and significantly enhanced erectile responses evoked by stimulation of the cavernous nerve. The mRNA expression for PDZ-RhoGEF, p115RhoGEF, and leukemia-associated RhoGEF in cavernosal segments was visualized by electrophoresis on agarose gel. The results indicate that H-1152 is a powerful Rho-kinase inhibitor, giving rise to its therapeutic potential in the treatment of erectile dysfunction. The regulator of G-protein signaling-containing RhoGEFs may represent key components of the molecular mechanisms associated with the abnormal function of the cavernosal smooth muscle.
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Affiliation(s)
- Cleber E Teixeira
- Department of Physiology, Medical College of Georgia, 1120 15th St., CA-3101, Augusta, GA 30912-3000, USA.
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Frazier EP, Mathy MJ, Peters SLM, Michel MC. Does cyclic AMP mediate rat urinary bladder relaxation by isoproterenol? J Pharmacol Exp Ther 2004; 313:260-7. [PMID: 15576470 DOI: 10.1124/jpet.104.077768] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Cyclic AMP is the prototypical second messenger of beta-adrenergic receptors, but recent findings have questioned its role in mediating smooth muscle relaxation upon beta-adrenergic receptor stimulation. We have investigated the signaling mechanisms underlying beta-adrenergic receptor-mediated relaxation of rat urinary bladder. Concentration-response curves for isoproterenol-induced bladder relaxation were generated in the presence or absence of inhibitors, with concomitant experiments using passive tension and KCl-induced precontraction. The adenylyl cyclase inhibitor 9-(tetrahydro-2-furanyl)-9H-purin-6-amine (SQ 22,536; 1 microM), the protein kinase A inhibitors 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H7; 10 microM), N-[2-(p-bromocinnamylamino)ethyl]-5-isoquinolinesulfonamide (H89; 1 microM), and Rp-adenosine 3',5'-cyclic monophosphorothioate (Rp-cAMPS; 30 microM), and the guanylyl cyclase inhibitor 1H-[1,2,4]oxadiazolo-[4,3-a]quinoxalin-1-one (ODQ; 3 microM) produced only minor if any inhibition of relaxation against passive tension or KCl-induced precontraction. Among various potassium channel inhibitors, BaCl2 (10 microM), tetraethylammonium (3 microM), apamin (300 nM), and glibenclamide (10 microM) did not inhibit isoproterenol-induced relaxation. Some inhibition of the isoproterenol effects against KCl-induced tone but not against passive tension was seen with inhibitors of calcium-dependent potassium channels such as charybdotoxin and iberiotoxin (30 nM each). A combination of SQ 22,536 and ODQ significantly inhibited relaxation against passive tension by about half, but not that against KCl-induced tone. Moreover, the combination failed to enhance inhibition by charybdotoxin against KCl-induced tone. We conclude that cAMP and cGMP each play a minor role in beta-adrenergic receptor-mediated relaxation against passive tension, and calcium-dependent potassium channels play a minor role against active tension.
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Affiliation(s)
- Elfaridah P Frazier
- Department of Pharmacology and Pharmacotherapy, University of Amsterdam, Academisch Medisch Centrum, The Netherlands
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