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Son NT, Gianibbi B, Panti A, Spiga O, Bastos JK, Fusi F. 3,3'-O-dimethylquercetin: A bi-functional vasodilator isolated from green propolis of the Caatinga Mimosa tenuiflora. Eur J Pharmacol 2024; 967:176400. [PMID: 38331336 DOI: 10.1016/j.ejphar.2024.176400] [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: 09/19/2023] [Revised: 01/29/2024] [Accepted: 02/06/2024] [Indexed: 02/10/2024]
Abstract
In the search for novel, bi-functional compounds acting as CaV1.2 channel blockers and K+ channel stimulators, which represent an effective therapy for hypertension, 3,3'-O-dimethylquercetin was isolated for the first time from Brazilian Caatinga green propolis. Its effects were investigated through electrophysiological, functional, and computational approaches. In rat tail artery myocytes, 3,3'-O-dimethylquercetin blocked Ba2+ currents through CaV1.2 channels (IBa1.2) in a concentration-dependent manner, with the inhibition being reversed upon washout. The compound also shifted the voltage dependence of the steady-state inactivation curve to more negative potentials without affecting the slope of the inactivation and activation curves. Furthermore, the flavonoid stimulated KCa1.1 channel currents (IKCa1.1). In silico simulations provided additional evidence for the binding of 3,3'-O-dimethylquercetin to KCa1.1 and CaV1.2 channels and elucidated its mechanism of action. In depolarized rat tail artery rings, the flavonoid induced a concentration-dependent relaxation. Moreover, in rat aorta rings its antispasmodic effect was inversely related to the transmembrane K+ gradient. In conclusion, 3,3'-O-dimethylquercetin demonstrates effective in vitro vasodilatory properties, encouraging the exploration of its scaffold to develop novel derivatives for potential use in the treatment of hypertension.
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Affiliation(s)
- Ninh The Son
- School of Pharmaceutical Sciences of Ribeirão Preto, Ribeirão Preto, University of São Paulo, Avenida Professor Doutor Zeferino Vaz, S/N, 14040-903, Ribeirão Preto-SP, Brazil; Institute of Chemistry, Vietnam Academy of Science and Technology (VAST), 18 Hoang Quoc Viet, Caugiay, Hanoi, 10000, Vietnam; Department of Chemistry, Graduate University of Science and Technology, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Caugiay, Hanoi, 10000, Vietnam
| | - Beatrice Gianibbi
- Dipartimento di Biotecnologie, Chimica e Farmacia, Università di Siena, Via A. Moro 2, 53100, Siena, Italy
| | - Alice Panti
- Dipartimento di Scienze della Vita, Università di Siena, Via A. Moro 2, 53100, Siena, Italy
| | - Ottavia Spiga
- Dipartimento di Biotecnologie, Chimica e Farmacia, Università di Siena, Via A. Moro 2, 53100, Siena, Italy
| | - Jairo Kenupp Bastos
- School of Pharmaceutical Sciences of Ribeirão Preto, Ribeirão Preto, University of São Paulo, Avenida Professor Doutor Zeferino Vaz, S/N, 14040-903, Ribeirão Preto-SP, Brazil.
| | - Fabio Fusi
- Dipartimento di Biotecnologie, Chimica e Farmacia, Università di Siena, Via A. Moro 2, 53100, Siena, Italy.
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2
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Awata WMC, Sousa AH, de Mello MMB, Dourado TMH, Pinheiro LC, Elias-Oliveira J, Rodrigues VF, Carlos D, Castro MM, Tirapelli CR. AT 1 receptors modulate ethanol-induced loss of anticontractile effect of perivascular adipose tissue. Biochem Pharmacol 2023; 217:115840. [PMID: 37783376 DOI: 10.1016/j.bcp.2023.115840] [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: 08/25/2023] [Revised: 09/28/2023] [Accepted: 09/29/2023] [Indexed: 10/04/2023]
Abstract
Ethanol consumption activates renin-angiotensin-aldosterone system (RAAS), which plays a major role in the pro-contractile and hypertensive effects linked to ethanol. We hypothesized that ethanol consumption induces loss of the anticontractile effect of perivascular adipose tissue (PVAT)through RAAS-mediated mechanisms. We examined the contribution of angiotensin II type 1 receptors (AT1R) to ethanol-induced PVAT dysfunction. With this purpose, male Wistar Hannover rats were treated with ethanol 20 % (in volume ratio) and/or losartan (antagonist of AT1R; 10 mg/kg/day, gavage) for 9 weeks. Losartan prevented the increase in blood pressure and the loss of the anticontractile effect of PVAT induced by ethanol consumption. PVAT dysfunction occurred after 3 and 9 weeks of treatment with ethanol in an endothelium-dependent manner. Blockade of AT1R prevented ethanol-induced reduction of adiponectin levels in PVAT from ethanol-treated rats. Functional assays revealed that ethanol impaired the anticontractile effect of PVAT-derived angiotensin (1-7) and endothelial nitric oxide (NO). In conclusion, AT1R are implicated in ethanol-induced loss of the anticontractile effect of PVAT. In PVAT, AT1R activation decreases the production of adiponectin, a PVAT-derived factor that promotes vasorelaxation in an endothelium-dependent manner. In the endothelium, AT1R favors the production of superoxide (O2•-) leading to a reduction in NO bioavailability. These responses impair the vasodilator action induced by PVAT-derived angiotensin (1-7), which occurs via Mas receptors located in endothelial cells. Ethanol-induced PVAT dysfunction favors vascular hypercontractility, a response that could contribute to the hypertensive state associated with ethanol consumption.
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Affiliation(s)
- Wanessa M C Awata
- Programa de Pós-Graduação em Farmacologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo (USP), Ribeirão Preto, São Paulo, Brazil; Laboratório de Farmacologia, Escola de Enfermagem de Ribeirão Preto, USP, Ribeirão Preto, São Paulo, Brazil
| | - Arthur H Sousa
- Programa de Pós-Graduação em Farmacologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo (USP), Ribeirão Preto, São Paulo, Brazil; Laboratório de Farmacologia, Escola de Enfermagem de Ribeirão Preto, USP, Ribeirão Preto, São Paulo, Brazil
| | - Marcela M B de Mello
- Programa de Pós-Graduação em Farmacologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo (USP), Ribeirão Preto, São Paulo, Brazil
| | - Thales M H Dourado
- Programa de Pós-Graduação em Farmacologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo (USP), Ribeirão Preto, São Paulo, Brazil; Laboratório de Farmacologia, Escola de Enfermagem de Ribeirão Preto, USP, Ribeirão Preto, São Paulo, Brazil
| | - Lucas C Pinheiro
- Laboratório de Farmacologia, Escola de Enfermagem de Ribeirão Preto, USP, Ribeirão Preto, São Paulo, Brazil
| | - Jefferson Elias-Oliveira
- Departamento de Bioquímica e Imunologia, Faculdade de Medicina de Ribeirão Preto, USP, Ribeirão Preto, São Paulo, Brazil
| | - Vanessa F Rodrigues
- Departamento de Bioquímica e Imunologia, Faculdade de Medicina de Ribeirão Preto, USP, Ribeirão Preto, São Paulo, Brazil
| | - Daniela Carlos
- Departamento de Bioquímica e Imunologia, Faculdade de Medicina de Ribeirão Preto, USP, Ribeirão Preto, São Paulo, Brazil
| | - Michele M Castro
- Programa de Pós-Graduação em Farmacologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo (USP), Ribeirão Preto, São Paulo, Brazil
| | - Carlos R Tirapelli
- Laboratório de Farmacologia, Escola de Enfermagem de Ribeirão Preto, USP, Ribeirão Preto, São Paulo, Brazil.
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3
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Dourado TMH, Assis VO, Awata WMC, Blascke de Mello MM, Cárnio EC, Castro MM, Tirapelli CR. Mineralocorticoid receptors contribute to ethanol-induced vascular hypercontractility through reactive oxygen species generation and up-regulation of cyclooxygenase 2. Eur J Pharmacol 2023; 949:175723. [PMID: 37059378 DOI: 10.1016/j.ejphar.2023.175723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 03/25/2023] [Accepted: 04/11/2023] [Indexed: 04/16/2023]
Abstract
The effects on blood pressure produced byethanol consumption include both vasoconstriction and activation of the renin-angiotensin-aldosterone system (RAAS), although the detailed relationship between these processes is yet to be accomplished. Here, we sought to investigate the contribution of mineralocorticoid receptors (MR) to ethanol-induced hypertension and vascular hypercontractility. We analyzed blood pressure and vascular function of male Wistar Hannover rats treated with ethanol for five weeks. The contribution of the MR pathway to the cardiovascular effects of ethanol was evaluated with potassium canrenoate, a MR antagonist (MRA). Blockade of MR prevented ethanol-induced hypertension and hypercontractility of endothelium-intact and -denuded aortic rings. Ethanol up-regulated cyclooxygenase (COX)2 and augmented vascular levels of both reactive oxygen species (ROS) and thromboxane (TX)B2, a stable metabolite of TXA2. These responses were abrogated by MR blockade. Hyperreactivity to phenylephrine induced by ethanol consumption was reversed by tiron [a scavenger of superoxide (O2∙-)], SC236 (a selective COX2 inhibitor) or SQ29548 (an antagonist of TP receptors). Treatment with the antioxidant apocynin prevented the vascular hypercontractility, as well as the increases in COX2 expression and TXA2 production induced by ethanol consumption. Our study has identified novel mechanisms through which ethanol consumption promotes its deleterious effects in the cardiovascular system. We provided evidence for a role of MR in the vascular hypercontractility and hypertension associated with ethanol consumption. The MR pathway triggers vascular hypercontractility through ROS generation, up-regulation of COX2 and overproduction of TXA2, which will ultimately induce vascular contraction.
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Affiliation(s)
- Thales M H Dourado
- Programa de Pós-Graduação em Farmacologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo (USP), Ribeirão Preto, São Paulo, Brazil; Laboratório de Farmacologia Cardiovascular, Escola de Enfermagem de Ribeirão Preto, USP, Ribeirão Preto, São Paulo, Brazil
| | - Victor O Assis
- Programa de Pós-Graduação em Farmacologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo (USP), Ribeirão Preto, São Paulo, Brazil; Laboratório de Farmacologia Cardiovascular, Escola de Enfermagem de Ribeirão Preto, USP, Ribeirão Preto, São Paulo, Brazil
| | - Wanessa M C Awata
- Programa de Pós-Graduação em Farmacologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo (USP), Ribeirão Preto, São Paulo, Brazil; Laboratório de Farmacologia Cardiovascular, Escola de Enfermagem de Ribeirão Preto, USP, Ribeirão Preto, São Paulo, Brazil
| | - Marcela M Blascke de Mello
- Programa de Pós-Graduação em Farmacologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo (USP), Ribeirão Preto, São Paulo, Brazil
| | - Evelin C Cárnio
- Laboratório de Fisiologia, Escola de Enfermagem de Ribeirão Preto, USP, Ribeirão Preto, São Paulo, Brazil
| | - Michele M Castro
- Programa de Pós-Graduação em Farmacologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo (USP), Ribeirão Preto, São Paulo, Brazil
| | - Carlos R Tirapelli
- Laboratório de Farmacologia Cardiovascular, Escola de Enfermagem de Ribeirão Preto, USP, Ribeirão Preto, São Paulo, Brazil.
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Carullo G, Saponara S, Ahmed A, Gorelli B, Mazzotta S, Trezza A, Gianibbi B, Campiani G, Fusi F, Aiello F. Novel Labdane Diterpenes-Based Synthetic Derivatives: Identification of a Bifunctional Vasodilator That Inhibits Ca V1.2 and Stimulates K Ca1.1 Channels. Mar Drugs 2022; 20:md20080515. [PMID: 36005518 PMCID: PMC9410420 DOI: 10.3390/md20080515] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Revised: 07/30/2022] [Accepted: 08/11/2022] [Indexed: 11/26/2022] Open
Abstract
Sesquiterpenes such as leucodin and the labdane-type diterpene manool are natural compounds endowed with remarkably in vitro vasorelaxant and in vivo hypotensive activities. Given their structural similarity with the sesquiterpene lactone (+)-sclareolide, this molecule was selected as a scaffold to develop novel vasoactive agents. Functional, electrophysiology, and molecular dynamics studies were performed. The opening of the five-member lactone ring in the (+)-sclareolide provided a series of labdane-based small molecules, promoting a significant in vitro vasorelaxant effect. Electrophysiology data identified 7 as a CaV1.2 channel blocker and a KCa1.1 channel stimulator. These activities were also confirmed in the intact vascular tissue. The significant antagonism caused by the CaV1.2 channel agonist Bay K 8644 suggested that 7 might interact with the dihydropyridine binding site. Docking and molecular dynamic simulations provided the molecular basis of the CaV1.2 channel blockade and KCa1.1 channel stimulation produced by 7. Finally, 7 reduced coronary perfusion pressure and heart rate, while prolonging conduction and refractoriness of the atrioventricular node, likely because of its Ca2+ antagonism. Taken together, these data indicate that the labdane scaffold represents a valuable starting point for the development of new vasorelaxant agents endowed with negative chronotropic properties and targeting key pathways involved in the pathophysiology of hypertension and ischemic cardiomyopathy.
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Affiliation(s)
- Gabriele Carullo
- Department of Life Sciences, University of Siena, Via Aldo Moro 2, 53100 Siena, Italy
| | - Simona Saponara
- Department of Life Sciences, University of Siena, Via Aldo Moro 2, 53100 Siena, Italy
| | - Amer Ahmed
- Department of Life Sciences, University of Siena, Via Aldo Moro 2, 53100 Siena, Italy
| | - Beatrice Gorelli
- Department of Life Sciences, University of Siena, Via Aldo Moro 2, 53100 Siena, Italy
| | - Sarah Mazzotta
- Department of Chemistry, University of Milan, Via Golgi 19, 20133 Milano, Italy
| | - Alfonso Trezza
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, Via Aldo Moro 2, 53100 Siena, Italy
| | - Beatrice Gianibbi
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, Via Aldo Moro 2, 53100 Siena, Italy
| | - Giuseppe Campiani
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, Via Aldo Moro 2, 53100 Siena, Italy
| | - Fabio Fusi
- Department of Biotechnology, Chemistry and Pharmacy, University of Siena, Via Aldo Moro 2, 53100 Siena, Italy
- Correspondence: (F.F.); (F.A.)
| | - Francesca Aiello
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, Edif. Polifunzionale, 87036 Arcavacata di Rende, Italy
- Correspondence: (F.F.); (F.A.)
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Cavalcanti ALDM, Rocha PKL, Zhuge Z, Paulo LL, Mendes-Júnior LDG, Brandão MCR, Athayde-Filho PF, Lundberg JO, Weitzberg E, Carlström M, Braga VDA, Montenegro MF. Cardiovascular characterization of the novel organic mononitrate NDIBP in rats. Nitric Oxide 2022; 119:50-60. [PMID: 34958954 DOI: 10.1016/j.niox.2021.12.007] [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: 06/30/2021] [Revised: 12/18/2021] [Accepted: 12/21/2021] [Indexed: 11/17/2022]
Abstract
Organic nitrates are widely used to restore endogenous nitric oxide (NO) levels reduced by endothelial nitric oxide synthase dysfunction. However, these drugs are associated with undesirable side effects, including tolerance. This study aims to investigate the cardiovascular effects of the new organic nitrate 1,3-diisobutoxypropan-2-yl nitrate (NDIBP). Specifically, we assessed its effects on blood pressure, vascular reactivity, acute toxicity, and the ability to induce tolerance. In vitro and ex vivo techniques showed that NDIBP released NO both in a cell-free system and in isolated mesenteric arteries preparations through a process catalyzed by xanthine oxidoreductase. NDIBP also evoked endothelium-independent vasorelaxation, which was significantly attenuated by 2-phenyl-4,4,5,5,-tetramethylimidazoline-1-oxyl 3-oxide (PTIO, 300 μM), a nitric oxide scavenger; 1-H-[1,2,4] oxadiazolo-[4,3-a]quinoxalin-1-one (ODQ, 10 μM), a soluble guanylyl cyclase inhibitor; tetraethylammonium (TEA, 3 mM), a potassium channel blocker; febuxostat (500 nM), a xanthine oxidase inhibitor; and proadifen (10 μM), an inhibitor of cytochrome P450 enzyme. Furthermore, this organic nitrate did not induce tolerance in isolated vessels and presented low toxicity following acute oral administration. In vivo changes on cardiovascular parameters were assessed using normotensive and renovascular hypertensive rats. NDIBP evoked a reduction of blood pressure that was significantly higher in hypertensive animals. Our results suggest that NDIBP acts as a NO donor, inducing blood pressure reduction without having the undesirable effects of tolerance. Those effects seem to be mediated by activation of NO-sGC-cGMP pathway and positive modulation of K+ channels in vascular smooth muscle.
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Affiliation(s)
| | - Patrícia Keytth Lins Rocha
- Biotechnology Center, Federal University of Paraíba, Cidade Universitária, 58051970, João Pessoa, PB, Brazil
| | - Zhengbing Zhuge
- Department of Physiology and Pharmacology, Karolinska Institutet, 171 65, Stockholm, Sweden
| | - Luciano Leite Paulo
- Biotechnology Center, Federal University of Paraíba, Cidade Universitária, 58051970, João Pessoa, PB, Brazil
| | | | | | - Petrônio F Athayde-Filho
- Department of Chemistry, Federal University of Paraíba, Cidade Universitária, 58059900, João Pessoa, PB, Brazil
| | - Jon O Lundberg
- Department of Physiology and Pharmacology, Karolinska Institutet, 171 65, Stockholm, Sweden
| | - Eddie Weitzberg
- Department of Physiology and Pharmacology, Karolinska Institutet, 171 65, Stockholm, Sweden
| | - Mattias Carlström
- Department of Physiology and Pharmacology, Karolinska Institutet, 171 65, Stockholm, Sweden
| | - Valdir de Andrade Braga
- Biotechnology Center, Federal University of Paraíba, Cidade Universitária, 58051970, João Pessoa, PB, Brazil.
| | - Marcelo F Montenegro
- Department of Physiology and Pharmacology, Karolinska Institutet, 171 65, Stockholm, Sweden
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Aekthammarat D, Pannangpetch P, Tangsucharit P. Moringa oleifera leaf extract induces vasorelaxation via endothelium-dependent hyperpolarization and calcium channel blockade in mesenteric arterial beds isolated from L-NAME hypertensive rats. Clin Exp Hypertens 2020; 42:490-501. [PMID: 31965874 DOI: 10.1080/10641963.2020.1714640] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND An aqueous extract of Moringa oleifera leaves (MOE) is known to cause relaxation of mesenteric resistance arteries of rats in which hypertension has been induced by the administration of L-NAME, but the mechanism(s) of action of MOE remains unclear. The purpose of this study was to investigate these mechanisms in mesenteric arterial beds isolated from L-NAME induced hypertensive rats. Methods: An investigation of vascular reactivity was conducted on isolated mesenteric arterial beds by measuring the changes in perfusion pressure using an in vitro system. RESULTS MOE (0.001-3 mg in 0.1 ml injection volume) caused a dose-dependent relaxation in methoxamine (5 µM) pre-contracted arterial beds, which was partially abolished by endothelium removal. The endothelium-dependent component of vasorelaxation was insensitive to both L-NAME (100 µM) and indomethacin (10 µM), while completely inhibited in high KCl (45 mM)-induced contraction. MOE (1 and 3 mg/ml) showed a dose-dependent inhibitory effect on CaCl2-induced contractions of denuded preparations in Ca2+-free medium containing a high KCl (60 mM) or methoxamine (10 µM). In Ca2+-free medium, MOE (3 mg/ml) also inhibited phenylephrine-induced contractions of denuded preparations. Conclusion: These findings suggest that MOE relaxes mesenteric arterial beds of L-NAME hypertensive rats via both endothelium-dependent and endothelium-independent mechanisms. The endothelium-dependent action occurred via endothelium-derived hyperpolarizing factor-mediated hyperpolarization. The endothelium-independent action was related to blocking the entry of extracellular Ca2+ via voltage-operated and receptor-operated Ca2+ channels, and inhibiting mobilization of sarcolemmal Ca2+ via inositol trisphosphate receptor Ca2+ channels. MOE may be potentially useful as a natural vasodilator against hypertension.
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Affiliation(s)
- Direk Aekthammarat
- Department of Pharmacology, Faculty of Medicine, Khon Kaen University , Khon Kaen, Thailand.,Cardiovascular Research Group, Khon Kaen University , Khon Kaen, Thailand
| | - Patchareewan Pannangpetch
- Department of Pharmacology, Faculty of Medicine, Khon Kaen University , Khon Kaen, Thailand.,Cardiovascular Research Group, Khon Kaen University , Khon Kaen, Thailand
| | - Panot Tangsucharit
- Department of Pharmacology, Faculty of Medicine, Khon Kaen University , Khon Kaen, Thailand.,Cardiovascular Research Group, Khon Kaen University , Khon Kaen, Thailand
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7
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Kubacka M, Kotańska M, Kazek G, Waszkielewicz AM, Marona H, Filipek B, Mogilski S. Involvement of the NO/sGC/cGMP/K + channels pathway in vascular relaxation evoked by two non-quinazoline α 1-adrenoceptor antagonists. Biomed Pharmacother 2018; 103:157-166. [PMID: 29653360 DOI: 10.1016/j.biopha.2018.04.034] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Revised: 04/04/2018] [Accepted: 04/05/2018] [Indexed: 02/06/2023] Open
Abstract
The aim of this study was to explore the α1-adrenoceptor-independent mechanisms involved in the vasorelaxant properties of two non-quinazoline α1-adrenoceptors antagonists (MH-76 and MH-79). Endothelium intact and endothelium denuded rat aorta was contracted with 1 μM phenylephrine to plateau, and the vasodilatory effect of MH-76 and MH-79 was examined in the absence or presence of inhibitors of the different signal transduction pathways. cGMP concetration was measured in rat aorta (enzyme immunoassay kit). In human aortic endothelial cells (HAEC) NO production was examined using a DAF-FM DA fluorescent indicator, whereas in human aortic smooth muscle cells the influence of the title compounds on K+ efflux was evaluated. The vasorelaxant effect of MH-76 and MH-79 was attenuated by endothelium removal, Nω-Nitro-l-arginine methyl ester (L-NAME) and 1H-[1,2,4]Oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) pretreatment to the level characteristic for α1-adrenoreceptor blocking activity. In addition, the MH-76 and MH-79 induced relaxation was reduced by K+ channels blockers. In endothelium intact rat aorta, MH-76 and MH-79 caused an increase in cGMP level, whereas in HAEC they increased NO generation. In contrast, the reference, quinazoline based α1-antagonist prazosin, did not influence NO production. Our findings suggest that the mechanisms underlying the vasodilatory properties of non-quinazoline based α1-adrenoceptors antagonists MH-76 and MH-79 involve not only α1-adrenoceptor blocking activity but also the activation of the endothelial NO-cGMP signalling pathway and the subsequent opening of K+ channels. Our studies show that such double mechanism of action is superior to pure α1-adrenoceptor blockade, and may be considered as a promising alternative for the prevention and treatment of cardiovascular diseases.
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Affiliation(s)
- Monika Kubacka
- Department of Pharmacodynamics, Faculty of Pharmacy, Medical College, Jagiellonian University, Medyczna 9, 30-688, Kraków, Poland.
| | - Magdalena Kotańska
- Department of Pharmacodynamics, Faculty of Pharmacy, Medical College, Jagiellonian University, Medyczna 9, 30-688, Kraków, Poland
| | - Grzegorz Kazek
- Department of Pharmacological Screening, Chair of Pharmacodynamics, Faculty of Pharmacy, Medical College, Jagiellonian University, Medyczna 9, 30-688, Kraków, Poland
| | - Anna Maria Waszkielewicz
- Department of Bioorganic Chemistry, Chair of Organic Chemistry, Faculty of Pharmacy, Medical College, Jagiellonian University, Medyczna 9, 30-688, Kraków, Poland
| | - Henryk Marona
- Department of Bioorganic Chemistry, Chair of Organic Chemistry, Faculty of Pharmacy, Medical College, Jagiellonian University, Medyczna 9, 30-688, Kraków, Poland
| | - Barbara Filipek
- Department of Pharmacodynamics, Faculty of Pharmacy, Medical College, Jagiellonian University, Medyczna 9, 30-688, Kraków, Poland
| | - Szczepan Mogilski
- Department of Pharmacodynamics, Faculty of Pharmacy, Medical College, Jagiellonian University, Medyczna 9, 30-688, Kraków, Poland
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8
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Leite LN, Gonzaga NA, Simplicio JA, do Vale GT, Carballido JM, Alves-Filho JC, Tirapelli CR. Pharmacological characterization of the mechanisms underlying the vascular effects of succinate. Eur J Pharmacol 2016; 789:334-343. [DOI: 10.1016/j.ejphar.2016.07.045] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Revised: 07/25/2016] [Accepted: 07/26/2016] [Indexed: 12/09/2022]
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9
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Pereira PC, Pernomian L, Côco H, Gomes MS, Franco JJ, Marchi KC, Hipólito UV, Uyemura SA, Tirapelli CR, de Oliveira AM. Auto-inhibitory regulation of angiotensin II functionality in hamster aorta during the early phases of dyslipidemia. Eur J Pharmacol 2016; 781:1-9. [DOI: 10.1016/j.ejphar.2016.04.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Revised: 03/31/2016] [Accepted: 04/07/2016] [Indexed: 10/22/2022]
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10
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Moreira JD, Pernomian L, Gomes MS, Moreira RP, do Prado AF, da Silva CHTP, de Oliveira AM. Enhanced nitric oxide generation from nitric oxide synthases as the cause of increased peroxynitrite formation during acute restraint stress: Effects on carotid responsiveness to angiotensinergic stimuli in type-1 diabetic rats. Eur J Pharmacol 2016; 783:11-22. [PMID: 27118175 DOI: 10.1016/j.ejphar.2016.04.050] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Revised: 04/21/2016] [Accepted: 04/22/2016] [Indexed: 12/20/2022]
Abstract
Diabetes mellitus is associated with reactive oxygen and nitrogen species accumulation. Behavioral stress increases nitric oxide production, which may trigger a massive impact on vascular cells and accelerate cardiovascular complications under oxidative stress conditions such as Diabetes. For this study, type-1 Diabetes mellitus was induced in Wistar rats by intraperitoneal injection of streptozotocin. After 28 days, cumulative concentration-response curves for angiotensin II were obtained in endothelium-intact carotid rings from diabetic rats that underwent to acute restraint stress for 3h. The contractile response evoked by angiotensin II was increased in carotid arteries from diabetic rats. Acute restraint stress did not alter angiotensin II-induced contraction in carotid arteries from normoglycaemic rats. However acute stress combined with Diabetes increased angiotensin II-induced contraction in carotid rings. Western blot experiments and the inhibition of nitric oxide synthases in functional assays showed that neuronal, endothelial and inducible nitric oxide synthase isoforms contribute to the increased formation of peroxynitrite and contractile hyperreactivity to angiotensin II in carotid rings from stressed diabetic rats. In summary, these findings suggest that the increased superoxide anion generation in carotid arteries from diabetic rats associated to the increased local nitric oxide synthases expression and activity induced by acute restrain stress were responsible for exacerbating the local formation of peroxynitrite and the contraction induced by angiotensin II.
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Affiliation(s)
- Josimar D Moreira
- Department of Clinical and Toxicological Analysis, Faculty of Pharmacy, Federal University from Minas Gerais, Belo Horizonte, MG, Brazil.
| | - Larissa Pernomian
- Department of Pharmaceutical Sciences, Faculty of Pharmaceutical Sciences from Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Mayara S Gomes
- Department of Physics and Chemistry, Faculty of Pharmaceutical Sciences from Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Rafael P Moreira
- Department of Internalization - Binational Campus, Federal University from Amapá, Oiapoque, AP, Brazil
| | - Alejandro F do Prado
- Institutional Capacity Building Program, Coordination of Earth Science and Ecology, Museum Paraense Emílio Goeldi (MPEG), Belém, PA, Brazil
| | - Carlos H T P da Silva
- Department of Pharmaceutical Sciences, Faculty of Pharmaceutical Sciences from Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Ana M de Oliveira
- Department of Physics and Chemistry, Faculty of Pharmaceutical Sciences from Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
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11
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Simplicio JA, Simão MR, Ambrosio SR, Tirapelli CR. The Labdane Ent-3-Acetoxy-Labda-8(17), 13-Dien-15-Oic Decreases Blood Pressure In Hypertensive Rats. Arq Bras Cardiol 2016; 106:481-90. [PMID: 27096521 PMCID: PMC4940147 DOI: 10.5935/abc.20160058] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Accepted: 02/23/2016] [Indexed: 11/20/2022] Open
Abstract
Background Labdane-type diterpenes induce lower blood pressure via relaxation of
vascular smooth muscle; however, there are no studies describing the effects
of labdanes in hypertensive rats. Objective The present study was designed to investigate the cardiovascular actions of
the labdane-type diterpene ent-3-acetoxy-labda-8(17), 13-dien-15-oic acid
(labda-15-oic acid) in two-kidney 1 clip (2K-1C) renal hypertension. Methods Vascular reactivity experiments were performed in aortic rings isolated from
2K-1C and normotensive (2K) male Wistar rats. Nitrate/nitrite (NOx)
measurement was performed in aortas by colorimetric assay. Blood pressure
measurements were performed in conscious rats. Results Labda-15-oic acid (0.1-300 µmol/l) and forskolin (0.1
nmol/l - 1 µmol/l) relaxed endothelium-intact and
endothelium-denuded aortas from both 2K-1C and 2K rats. Labda-15-oic acid
was more effective at inducing relaxation in endothelium-intact aortas from
2K pre-contracted with phenylephrine when compared to the
endothelium-denuded ones. Forskolin was more potent than labda-15-oic acid
at inducing vascular relaxation in arteries from both 2K and 2K-1C rats.
Labda-15-oic acid-induced increase in NOx levels was lower in arteries from
2K-1C rats when compared to 2K rats. Intravenous administration of
labda-15-oic acid (0.3-3 mg/kg) or forskolin (0.1-1 mg/kg) induced
hypotension in conscious 2K-1C and 2K rats. Conclusion The present findings show that labda-15-oic acid induces vascular relaxation
and hypotension in hypertensive rats.
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Affiliation(s)
- Janaina A Simplicio
- Programa de Pós-Graduação em Farmacologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil
| | - Marilia R Simão
- Núcleo de Pesquisa em Ciências e Tecnologia, Universidade de Franca, Franca, SP, Brazil
| | - Sergio R Ambrosio
- Núcleo de Pesquisa em Ciências e Tecnologia, Universidade de Franca, Franca, SP, Brazil
| | - Carlos R Tirapelli
- Laboratório de Farmacologia, Escola de Enfermagem de Ribeirão Preto, USP, Ribeirão Preto, SP, Brazil
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12
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de Fátima Reis C, de Andrade DML, Neves BJ, de Almeida Ribeiro Oliveira L, Pinho JF, da Silva LP, Cruz JDS, Bara MTF, Andrade CH, Rocha ML. Blocking the L-type Ca2+ channel (Cav 1.2) is the key mechanism for the vascular relaxing effect of Pterodon spp. and its isolated diterpene methyl-6α-acetoxy-7β-hydroxyvouacapan-17β-oate. Pharmacol Res 2015; 100:242-9. [DOI: 10.1016/j.phrs.2015.08.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Revised: 07/14/2015] [Accepted: 08/07/2015] [Indexed: 11/27/2022]
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13
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Pernomian L, do Prado AF, Gomes MS, Pernomian L, da Silva CH, Gerlach RF, de Oliveira AM. MAS receptors mediate vasoprotective and atheroprotective effects of candesartan upon the recovery of vascular angiotensin-converting enzyme 2–angiotensin-(1-7)–MAS axis functionality. Eur J Pharmacol 2015; 764:173-188. [DOI: 10.1016/j.ejphar.2015.07.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Revised: 06/30/2015] [Accepted: 07/01/2015] [Indexed: 11/15/2022]
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14
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Moreira JD, Pernomian L, Gomes MS, Pernomian L, Moreira RP, do Prado AF, da Silva CHTP, de Oliveira AM. Acute restraint stress increases carotid reactivity in type-I diabetic rats by enhancing Nox4/NADPH oxidase functionality. Eur J Pharmacol 2015; 765:503-16. [PMID: 26387612 DOI: 10.1016/j.ejphar.2015.09.020] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Revised: 08/16/2015] [Accepted: 09/14/2015] [Indexed: 12/23/2022]
Abstract
Hyperglycemia increases the generation of reactive oxygen species and affects systems that regulate the vascular tone including renin-angiotensin system. Stress could exacerbate intracellular oxidative stress during Diabetes upon the activation of angiotensin AT1/NADPH oxidase pathway, which contributes to the development of diabetic cardiovascular complications. For this study, type-I Diabetes was induced in Wistar rats by intraperitoneal injection of streptozotocin. 28 days after streptozotocin injection, the animals underwent to acute restraint stress for 3 h. Cumulative concentration-response curves for angiotensin II were obtained in carotid rings pre-treated or not with Nox or cyclooxygenase inhibitors. Nox1 or Nox4 expression and activity were assessed by Western blotting and lucigenin chemiluminescence, respectively. The role of Nox1 and Nox4 on reactive oxygen species generation was evaluated by flow cytometry and Amplex Red assays. Cyclooxygenases expression was assessed by real-time polymerase chain reaction. The contractile response evoked by angiotensin II was increased in diabetic rat carotid. Acute restraint stress increased this response in this vessel by mechanisms mediated by Nox4, whose local expression and activity in generating hydrogen peroxide are increased. The contractile hyperreactivity to angiotensin II in stressed diabetic rat carotid is also mediated by metabolites derived from cyclooxygenase-2, whose local expression is increased. Taken together, our findings suggest that acute restraint stress exacerbates the contractile hyperreactivity to angiotensin II in diabetic rat carotid by enhancing Nox4-driven generation of hydrogen peroxide, which evokes contractile tone by cyclooxygenases-dependent mechanisms. Finally, these findings highlight the harmful role played by acute stress in modulating diabetic vascular complications.
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Affiliation(s)
- Josimar D Moreira
- Department of Clinical and Toxicological Analysis, Faculty of Pharmacy, Federal University from Minas Gerais (UFMG), Belo Horizonte, MG, Brazil.
| | - Larissa Pernomian
- Department of Pharmaceutical Sciences, Faculty of Pharmaceutical Sciences from Ribeirão Preto (FCFRP), University of São Paulo (USP), Ribeirão Preto, SP, Brazil
| | - Mayara S Gomes
- Department of Physics and Chemistry, FCFRP, USP, Ribeirão Preto, SP, Brazil
| | - Laena Pernomian
- Department of Pharmacology, Faculty of Medicine from Ribeirão Preto (FMRP), USP, Ribeirão Preto, SP, Brazil
| | - Rafael P Moreira
- Department of Physics and Chemistry, FCFRP, USP, Ribeirão Preto, SP, Brazil
| | - Alejandro F do Prado
- Department of Pharmacology, Faculty of Medicine from Ribeirão Preto (FMRP), USP, Ribeirão Preto, SP, Brazil
| | - Carlos H T P da Silva
- Department of Pharmaceutical Sciences, Faculty of Pharmaceutical Sciences from Ribeirão Preto (FCFRP), University of São Paulo (USP), Ribeirão Preto, SP, Brazil
| | - Ana M de Oliveira
- Department of Physics and Chemistry, FCFRP, USP, Ribeirão Preto, SP, Brazil
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Ribeiro LAA, Alencar Filho EB, Coelho MC, Silva BA. The vasorelaxant effect of 8(17),12E,14-labdatrien-18-oic acid involves stimulation of adenylyl cyclase and cAMP/PKA pathway: Evidences by pharmacological and molecular docking studies. Eur J Pharmacol 2015; 764:363-371. [PMID: 26144373 DOI: 10.1016/j.ejphar.2015.06.063] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Revised: 06/19/2015] [Accepted: 06/30/2015] [Indexed: 11/24/2022]
Abstract
The relaxant effect of 8(17),12E,14-labdatrien-18-oic acid (LBD) was investigated on isolated aortic rings and compared with forskolin (FSK), a standard and potent activator of adenylyl cyclase (AC) with relaxing effect. The presence of potassium channel blockers, such as glibenclamide (ATP-blocker), apamin (SKCa-blocker), charybdotoxin (BKCa-blocker) did not significantly affect either the LBD or FSK concentration-response curves. However, in the presence of 4-aminopyridine (KV-blocker), the relaxant effect for both diterpenes was significantly attenuated, with reduction of its relative potencies. Moreover, the relaxation induced by 8-Br-cAMP, an analog of cAMP, was also significantly attenuated in the same conditions, i.e., in the presence of 4-aminopyridine. The presence of aminophylline, a nonselective phosphodiesterase inhibitor, caused a significant increasing in the potency for both LBD and FSK. On the other hand, the presence of Rp-cAMPS, a selective PKA-inhibitor, significantly attenuated the relaxant effect of LBD. In this work, in the same experimental conditions, both labdane-type diterpenes presented remarkably similar results; FSK, however, presented a higher potency (100-fold) than LBD. Thus, the hypothesis that LBD could be a novel AC-activator emerged. To assess that hypothesis, computational molecular docking studies were performed. Crystallographic structure of adenylyl cyclase/forskolin complex (1AB8) was obtained from RSCB Protein Data Bank and used to compare the modes of interaction of the native ligand and LBD. The computational data shows many similarities between LBD and FSK concerning the interaction with the regulatory site of AC. Taken together, the results presented here pointed to LBD as a novel AC-activator.
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Affiliation(s)
- Luciano A A Ribeiro
- Colegiado de Farmácia (CFARM), Universidade Federal do Vale do São Francisco (UNIVASF), Av. José de Sá Maniçoba, S/No, Campus Centro, P.O. Box 252, CEP:56304-205, Petrolina, PE, Brazil; Programa de Pós-Graduação em Recursos Naturais do Semiárido (PGRNSA), Universidade Federal do Vale do São Francisco (UNIVASF), 56304-205, Petrolina, PE, Brazil.
| | - Edilson B Alencar Filho
- Colegiado de Farmácia (CFARM), Universidade Federal do Vale do São Francisco (UNIVASF), Av. José de Sá Maniçoba, S/No, Campus Centro, P.O. Box 252, CEP:56304-205, Petrolina, PE, Brazil
| | - Maisa C Coelho
- Curso de Graduação em Farmácia, Universidade Federal do Vale do São Francisco (UNIVASF), 56304-205, Petrolina, PE, Brazil
| | - Bagnólia A Silva
- Universidade Federal da Paraíba, Laboratório de Tecnologia Farmacêutica-Campus I. Cidade Universitária, 58051-970, Joao Pessoa, PB, Brazil
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de Barros Correia Junior CA, Bezerra de Siqueira RJ, Leal Interaminense LF, Alves-Santos TR, Duarte GP, David JM, David JP, Magalhães PJC, Lahlou S. Cardiovascular effects of a labdenic diterpene isolated from Moldenhawera nutans in conscious, spontaneously hypertensive rats. PHARMACEUTICAL BIOLOGY 2015; 53:582-587. [PMID: 25489636 DOI: 10.3109/13880209.2014.934964] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
CONTEXT The labdenic diterpene labd-8(17)-en-15-oic acid (labd-8) isolated from a methanolic extract of Moldenhawera nutans Queiroz & Alkin (Leguminosae) has hypotensive and tachycardiac properties in normotensive rats. A part of the hypotensive effect was due to a reduction in the sympathetic nerve drive to vessels, an event admittedly enhanced in spontaneously hypertensive rats (SHRs). OBJECTIVES We assessed whether the cardiovascular effects induced by labd-8 could be enhanced in SHRs. MATERIALS AND METHODS For in vivo experiments, arterial and venous catheters were implanted under anesthesia for blood pressure recording and drug administration, respectively. For in vitro experiments, thoracic aorta rings were suspended in organ baths containing warm (37 °C) perfusion medium that was continuously bubbled with carbogen. RESULTS Intravenous injection of labd-8 (1, 3, 5, and 10 mg/kg) induced similar dose-dependent hypotension and tachycardia in both SHRs and Wistar-Kyoto rats (WKY). In SHRs, only the tachycardia response to labd-8 was significantly reduced by pretreatment with methylatropine or propranolol. However, both cardiovascular effects of labd-8 were reduced by hexamethonium while remained unchanged by l-NAME. In isolated aortic preparations from SHRs, labd-8 (1-1000 µg/mL) relaxed potassium-induced contractions with an IC50 (geometric mean [95% confidence interval]) value (536.5 [441.0-631.9] µg/mL) significantly greater than that (157.6 [99.1-250.5] µg/mL) obtained in preparations from WKY rats. CONCLUSION In SHRs, the hypotension induced by labd-8 is associated with a reflex tachycardia and seems mediated partly through withdrawal of sympathetic vasomotor tone and partly through an active vasorelaxation. Its magnitude was not enhanced when compared with WKY rats likely because of impaired vasorelaxant effects of labd-8 in preparations from SHRs.
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17
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Leite LN, Gonzaga NA, Tirapelli DPC, Tirapelli LF, Tirapelli CR. Pharmacological characterization of the relaxant effect induced by adrenomedullin in rat cavernosal smooth muscle. Braz J Med Biol Res 2014; 47:876-85. [PMID: 25140812 PMCID: PMC4181223 DOI: 10.1590/1414-431x20143911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Accepted: 05/09/2014] [Indexed: 11/22/2022] Open
Abstract
The aim of the present study was to determine the mechanisms underlying the relaxant
effect of adrenomedullin (AM) in rat cavernosal smooth muscle (CSM) and the
expression of AM system components in this tissue. Functional assays using standard
muscle bath procedures were performed in CSM isolated from male Wistar rats. Protein
and mRNA levels of pre-pro-AM, calcitonin receptor-like receptor (CRLR), and Subtypes
1, 2 and 3 of the receptor activity-modifying protein (RAMP) family were assessed by
Western immunoblotting and quantitative real-time polymerase chain reaction,
respectively. Nitrate and 6-keto-prostaglandin F1α
(6-keto-PGF1α; a stable product of prostacyclin) levels were determined
using commercially available kits. Protein and mRNA of AM, CRLR, and RAMP 1, -2, and
-3 were detected in rat CSM. Immunohistochemical assays demonstrated that AM and CRLR
were expressed in rat CSM. AM relaxed CSM strips in a concentration-dependent manner.
AM22-52, a selective antagonist for AM receptors, reduced the
relaxation induced by AM. Conversely, CGRP8-37, a selective antagonist for
calcitonin gene-related peptide receptors, did not affect AM-induced relaxation.
Preincubation of CSM strips with NG-nitro-L-arginine-methyl-ester (L-NAME,
nitric oxide synthase inhibitor), 1H-(1,2,4)oxadiazolo[4,3-a]quinoxalin-1-one (ODQ,
quanylyl cyclase inhibitor), Rp-8-Br-PET-cGMPS (cGMP-dependent protein kinase
inhibitor), SC560 [5-(4-chlorophenyl)-1-(4-methoxyphenyl)-3-trifluoromethyl pyrazole,
selective cyclooxygenase-1 inhibitor], and 4-aminopyridine (voltage-dependent
K+ channel blocker) reduced AM-induced relaxation. On the other hand,
7-nitroindazole (selective neuronal nitric oxide synthase inhibitor), wortmannin
(phosphatidylinositol 3-kinase inhibitor), H89 (protein kinase A inhibitor), SQ22536
[9-(tetrahydro-2-furanyl)-9H-purin-6-amine, adenylate cyclase inhibitor],
glibenclamide (selective blocker of ATP-sensitive K+ channels), and apamin
(Ca2+-activated channel blocker) did not affect AM-induced relaxation.
AM increased nitrate levels and 6-keto-PGF1α in rat CSM. The major new
contribution of this research is that it demonstrated expression of AM and its
receptor in rat CSM. Moreover, we provided evidence that AM-induced relaxation in
this tissue is mediated by AM receptors by a mechanism that involves the nitric
oxide-cGMP pathway, a vasodilator prostanoid, and the opening of voltage-dependent
K+ channels.
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Affiliation(s)
- L N Leite
- Programa de Pós-Graduação em Farmacologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brasil
| | - N A Gonzaga
- Programa de Pós-Graduação em Farmacologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brasil
| | - D P C Tirapelli
- Departamento de Cirurgia e Anatomia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brasil
| | - L F Tirapelli
- Departamento de Cirurgia e Anatomia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brasil
| | - C R Tirapelli
- Laboratório de Farmacologia, Departamento de Enfermagem Psiquiátrica e Ciências Humanas, Escola de Enfermagem de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brasil
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