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Britto-Júnior J, Guimarães RAB, Oliveira DL, Lima AT, Quirino Junior G, de Oliveira Stocco GA, Salgado Uramoto EH, Fregonesi A, Antunes E, De Nucci G. Alpha 1-adrenergic blockers selectively antagonize the contractions induced by 6-nitrodopamine in the human vas deferens. NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 2024; 397:3227-3238. [PMID: 37910185 DOI: 10.1007/s00210-023-02805-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2023] [Accepted: 10/19/2023] [Indexed: 11/03/2023]
Abstract
6-Nitrodopamine (6-ND) is released from human vas deferens and plays a modulatory role in the male ejaculation. Therapeutical use of α1-adrenoceptor antagonists is associated with ejaculatory abnormalities. To evaluate the effect of α1-adrenoceptor antagonists on the contractions induced by 6-ND, dopamine, noradrenaline, and adrenaline in the human epididymal vas deferens (HEVD). HEVD strips were suspended in glass chambers containing heated and oxygenated Krebs-Henseleit's solution. Cumulative concentration-response curves to catecholamines (10 nM-300 μM) were constructed in HEVD strips pre-incubated (30 min) with doxazosin (0.1-1 nM), tamsulosin (1-10 nM), prazosin (10-100 nM) and/or silodosin (0.1-10 nM). The effects of these α1-adrenoceptor antagonists were also evaluated in the electric-field stimulation (EFS, 2-32 Hz)-induced contractions. Doxazosin (0.1 nM) caused significant reductions in 6-ND-induced HEVD contractions without affecting the contractions induced by dopamine, noradrenaline, and adrenaline. Similar results were observed with tamsulosin (1 nM) and prazosin (10 nM). At these concentrations, these α1-adrenoceptor antagonists largely reduced the EFS-induced contractions. Silodosin (1 nM) caused concentration-dependent rightward shifts of the concentration-response curves to 6-ND but had no effect on the contractions induced by dopamine and adrenaline. Silodosin (0.1 nM) only inhibited the contractions induced by noradrenaline. Silodosin at 1 nM, but not at 0.1 nM, caused significant reductions in the EFS-induced contractions. The results reinforce the concept that 6-ND plays a major role in the human vas deferens contractility and indicate that the ejaculation disorders caused by doxazosin, tamsulosin, prazosin and silodosin cause in man, may be due to inhibition of the contractions induced by 6-ND rather than by the classical catecholamines dopamine, noradrenaline, and adrenaline.
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Affiliation(s)
- José Britto-Júnior
- Department of Pharmacology, Faculty of Medical Sciences, State University of Campinas, 126 Tessália Vieira de Camargo St, Campinas, Sao Paulo, 13083-887, Brazil.
| | - Renan Arthur Bosio Guimarães
- Department of Pharmacology, Faculty of Medical Sciences, State University of Campinas, 126 Tessália Vieira de Camargo St, Campinas, Sao Paulo, 13083-887, Brazil
| | - Denis Lima Oliveira
- Department of Pharmacology, Faculty of Medical Sciences, State University of Campinas, 126 Tessália Vieira de Camargo St, Campinas, Sao Paulo, 13083-887, Brazil
| | - Antonio Tiago Lima
- Department of Pharmacology, Faculty of Medical Sciences, State University of Campinas, 126 Tessália Vieira de Camargo St, Campinas, Sao Paulo, 13083-887, Brazil
| | - Gilberto Quirino Junior
- Department of Pharmacology, Faculty of Medical Sciences, State University of Campinas, 126 Tessália Vieira de Camargo St, Campinas, Sao Paulo, 13083-887, Brazil
| | - Gabriel Augusto de Oliveira Stocco
- Department of Pharmacology, Faculty of Medical Sciences, State University of Campinas, 126 Tessália Vieira de Camargo St, Campinas, Sao Paulo, 13083-887, Brazil
| | | | - Adriano Fregonesi
- Department of Pharmacology, Faculty of Medical Sciences, State University of Campinas, 126 Tessália Vieira de Camargo St, Campinas, Sao Paulo, 13083-887, Brazil
- Department of Surgery, Faculty of Medicine of Jundiaí, Jundiaí, Brazil
| | - Edson Antunes
- Department of Pharmacology, Faculty of Medical Sciences, State University of Campinas, 126 Tessália Vieira de Camargo St, Campinas, Sao Paulo, 13083-887, Brazil
| | - Gilberto De Nucci
- Department of Pharmacology, Faculty of Medical Sciences, State University of Campinas, 126 Tessália Vieira de Camargo St, Campinas, Sao Paulo, 13083-887, Brazil
- Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
- Metropolitan University of Santos, Santos, Brazil
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Zatz R, De Nucci G. Endothelium-Derived Dopamine and 6-Nitrodopamine in the Cardiovascular System. Physiology (Bethesda) 2024; 39:44-59. [PMID: 37874898 PMCID: PMC11283902 DOI: 10.1152/physiol.00020.2023] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 10/09/2023] [Accepted: 10/20/2023] [Indexed: 10/26/2023] Open
Abstract
The review deals with the release of endothelium-derived dopamine and 6-nitrodopamine (6-ND) and its effects on isolated vascular tissues and isolated hearts. Basal release of both dopamine and 6-ND is present in human isolated umbilical cord vessels, human popliteal vessels, nonhuman primate vessels, and reptilia aortas. The 6-ND basal release was significantly reduced when the tissues were treated with Nω-nitro-l-arginine methyl ester and virtually abolished when the endothelium was mechanically removed. 6-Nitrodopamine is a potent vasodilator, and the mechanism of action responsible for this effect is the antagonism of dopamine D2-like receptors. As a vasodilator, 6-ND constitutes a novel mechanism by which nitric oxide modulates vascular tone. The basal release of 6-ND was substantially decreased in endothelial nitric oxide synthase knockout (eNOS-/-) mice and not altered in neuronal nitric oxide synthase knockout (nNOS-/-) mice, indicating a nonneurogenic source for 6-ND in the heart. Indeed, in rat isolated right atrium, the release of 6-ND was not affected when the atria were treated with tetrodotoxin. In the rat isolated right atrium, 6-ND is the most potent endogenous positive chronotropic agent, and in Langendorff's heart preparation, it is the most potent endogenous positive inotropic agent. The positive chronotropic and inotropic effects of 6-ND are antagonized by β1-adrenoceptor antagonists at concentrations that do not affect the effects induced by noradrenaline, adrenaline, and dopamine, indicating that blockade of the 6-ND receptor is the major modulator of heart chronotropism and inotropism. The review proposes that endothelium-derived catecholamines may constitute a major mechanism for control of vascular tone and heart functions, in contrast to the overrated role attributed to the autonomic nervous system.
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Affiliation(s)
- Roberto Zatz
- Renal Division, Department of Clinical Medicine, Faculty of Medicine, University of São Paulo, São Paulo, Brazil
| | - Gilberto De Nucci
- Department of Pharmacology, Faculty of Medical Sciences, State University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
- Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo (ICB-USP), São Paulo, Brazil
- Department of Pharmacology, Faculty of Medicine, São Leopoldo Mandic, Campinas, São Paulo, Brazil
- Department of Pharmacology, Faculty of Medicine, Metropolitan University of Santos, Santos, São Paulo, Brazil
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