A 7-metoxiflavona apresenta efeito tocolítico por modulação negativa da via Rho cinase e da calmodulina em ratas
Autor(a) principal: | |
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Data de Publicação: | 2018 |
Tipo de documento: | Dissertação |
Idioma: | por |
Título da fonte: | Biblioteca Digital de Teses e Dissertações da UFPB |
Texto Completo: | https://repositorio.ufpb.br/jspui/handle/123456789/13655 |
Resumo: | Since the 7-methoxyflavone flavonoid (7-MF), one of the major components isolated from Zornia brasiliensis Vogel, showed in vitro tocolytic effect in rats, it was decided to characterize this mechanism. The rat uterus was placed in baths for isolated organ where isotonic and isometric contractions were monitored (n = 5). It was observed that 7-MF relaxed the pre-contracted rat uterus by both oxytocin (OCI) (EC50 = 3.5 ± 0.3 x 10-5 M) and KCl (EC50 = 2.2 ± 0.2 x 10-5 M) being about 2 times more potent compared to this contractile agent, suggesting a participation of voltage-dependent calcium channels (CaV) in tocolytic effect of 7-MF. To confirm this hypothesis, cumulative curves to CaCl2 were performed in the absence and presence of 7-MF and a shift of the control curve to the right was observed, with a reduction of maximum effect only at the concentration of 3 x 10-5 M (30%), indicating that probably blocking Ca2+ influx through CaV is not the main tocolytic mechanism of flavonoid. It was decided to evaluate a possible participation of the potassium channels in tocolytic effect of 7-MF using cesium chloride, a non-selective K+ channel blocker, and in this presence control curve of 7-MF relaxation was not deviated (EC50 = 3.3 ± 0.6 × 10-5 M ), discarding positive modulation of the K+ channels in tocolytic effect of 7-MF. Once prostaglandins are involved in physiopathological uterine processes and the inhibitors of cyclooxygenase (COXs) are one of the main classes used for the treatment of dysmenorrhea so, it was decided to evaluate the possible involvement of the COXs pathway in the tocolytic mechanism of 7-MF and it was observed that in the presence of indomethacin, a nonselective COXs inhibitor, the control curve was not displaced (EC50 = 4.8 ± 0.6 x 10-5 M), indicating that the inhibition of these enzymes are not involved in the tocolytic effect of 7-MF. Another pathway of smooth muscle relaxation is adrenergic-β receptors. In order to evaluate a possible activation of these in the action of 7-MF, used (S)-(-)-propranolol, a adrenergic-β receptor antagonist, was used and it was observed that there was no change in the relaxing potency in the presence of the blocker (EC50 = 2.2 ± 0.5 x 10-5 M), indicating that 7-MF does not act by positive modulation of these receptors to induce the tocolytic effect. As a major route of relaxation of the smooth muscle is the nitric oxide (NO) pathway, it was decided to evaluate the participation of this pathway in the tocolytic effect of 7-MF and it was observed that in the presence of L-NAME, a non-selective inhibitor of NO synthase (NOS), there was no change in the relaxing potency (EC50 = 4.4 ± 1.2 x 10-5 M), also discarding this pathway in tocolytic effect of 7-MF. A common downstream step of the Gs and NO pathways is the enzyme phosphodiesterase (PDE). In the presence of aminophylline, a non-selective PDE, it was observed that there was no change in the relaxing potency of 7-MF (EC50 = 2.8 ± 0.5 x 10-5 M) indicating that it is probably not by its activation that the flavonoid exerts its tocolytic effect. Inhibition of contractile pathways can also lead to smooth muscle relaxation, thus the RhoA/Rho kinase pathway (ROCK) participation in the tocolytic effect of 7-MF was evaluated. In the presence of Y-27632, a non-selective ROCK blocker, the curve was shifted to the left, with an increase in the relaxation potency around 22 times (EC50 = 1.6 ± 0.7 x 10-6 M) suggesting that 7-MF negatively modulates the RhoA/ROCK pathway to exert its tocolytic effect. Still in the contractile mechanism, calmodulin is one of the main mediators for Ca2+ signaling. In order to evaluate its participation in the tocolytic effect of 7-MF used calmidazolium, a calmodulin blocker, and was observed a potentiation of the relaxing effect of 7-MF (EC50 = 6.5 ± 1.6 x 10-7 M), around 54 times, confirming negative modulation of calmodulina in tocolytic effect. Thus, the mechanism of tocolytic action proposed for 7-MF in rats is the inhibition of the ROCK pathway and calmodulin. |
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A 7-metoxiflavona apresenta efeito tocolítico por modulação negativa da via Rho cinase e da calmodulina em ratasMetoxiflavonaTocolíticoÚtero de rataRhoA/Rho cinaseCalmodulinaMethoxyflavoneTocolyticRat uterusRhoA/Rho kinaseCalmodulinSubstâncias naturais - Ação bioativasZornia brasilienses VogelCarrapichoTestes em ratasCNPQ::CIENCIAS BIOLOGICAS::FARMACOLOGIASince the 7-methoxyflavone flavonoid (7-MF), one of the major components isolated from Zornia brasiliensis Vogel, showed in vitro tocolytic effect in rats, it was decided to characterize this mechanism. The rat uterus was placed in baths for isolated organ where isotonic and isometric contractions were monitored (n = 5). It was observed that 7-MF relaxed the pre-contracted rat uterus by both oxytocin (OCI) (EC50 = 3.5 ± 0.3 x 10-5 M) and KCl (EC50 = 2.2 ± 0.2 x 10-5 M) being about 2 times more potent compared to this contractile agent, suggesting a participation of voltage-dependent calcium channels (CaV) in tocolytic effect of 7-MF. To confirm this hypothesis, cumulative curves to CaCl2 were performed in the absence and presence of 7-MF and a shift of the control curve to the right was observed, with a reduction of maximum effect only at the concentration of 3 x 10-5 M (30%), indicating that probably blocking Ca2+ influx through CaV is not the main tocolytic mechanism of flavonoid. It was decided to evaluate a possible participation of the potassium channels in tocolytic effect of 7-MF using cesium chloride, a non-selective K+ channel blocker, and in this presence control curve of 7-MF relaxation was not deviated (EC50 = 3.3 ± 0.6 × 10-5 M ), discarding positive modulation of the K+ channels in tocolytic effect of 7-MF. Once prostaglandins are involved in physiopathological uterine processes and the inhibitors of cyclooxygenase (COXs) are one of the main classes used for the treatment of dysmenorrhea so, it was decided to evaluate the possible involvement of the COXs pathway in the tocolytic mechanism of 7-MF and it was observed that in the presence of indomethacin, a nonselective COXs inhibitor, the control curve was not displaced (EC50 = 4.8 ± 0.6 x 10-5 M), indicating that the inhibition of these enzymes are not involved in the tocolytic effect of 7-MF. Another pathway of smooth muscle relaxation is adrenergic-β receptors. In order to evaluate a possible activation of these in the action of 7-MF, used (S)-(-)-propranolol, a adrenergic-β receptor antagonist, was used and it was observed that there was no change in the relaxing potency in the presence of the blocker (EC50 = 2.2 ± 0.5 x 10-5 M), indicating that 7-MF does not act by positive modulation of these receptors to induce the tocolytic effect. As a major route of relaxation of the smooth muscle is the nitric oxide (NO) pathway, it was decided to evaluate the participation of this pathway in the tocolytic effect of 7-MF and it was observed that in the presence of L-NAME, a non-selective inhibitor of NO synthase (NOS), there was no change in the relaxing potency (EC50 = 4.4 ± 1.2 x 10-5 M), also discarding this pathway in tocolytic effect of 7-MF. A common downstream step of the Gs and NO pathways is the enzyme phosphodiesterase (PDE). In the presence of aminophylline, a non-selective PDE, it was observed that there was no change in the relaxing potency of 7-MF (EC50 = 2.8 ± 0.5 x 10-5 M) indicating that it is probably not by its activation that the flavonoid exerts its tocolytic effect. Inhibition of contractile pathways can also lead to smooth muscle relaxation, thus the RhoA/Rho kinase pathway (ROCK) participation in the tocolytic effect of 7-MF was evaluated. In the presence of Y-27632, a non-selective ROCK blocker, the curve was shifted to the left, with an increase in the relaxation potency around 22 times (EC50 = 1.6 ± 0.7 x 10-6 M) suggesting that 7-MF negatively modulates the RhoA/ROCK pathway to exert its tocolytic effect. Still in the contractile mechanism, calmodulin is one of the main mediators for Ca2+ signaling. In order to evaluate its participation in the tocolytic effect of 7-MF used calmidazolium, a calmodulin blocker, and was observed a potentiation of the relaxing effect of 7-MF (EC50 = 6.5 ± 1.6 x 10-7 M), around 54 times, confirming negative modulation of calmodulina in tocolytic effect. Thus, the mechanism of tocolytic action proposed for 7-MF in rats is the inhibition of the ROCK pathway and calmodulin.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPESUma vez que o flavonoide 7-metoxiflavona (7-MF), um dos componentes majoritários isolados de Zornia brasiliensis Vogel, apresentou efeito tocolítico in vitro em ratas, resolveu-se caracterizar esse mecanismo de ação. O útero de rata era montado em cubas de banhos para órgão isolado onde as contrações isotônicas e isométricas eram monitoradas (n = 5). Observou-se que a 7-MF relaxou o útero de rata pré-contraído tanto por ocitocina (OCI) (CE50 = 3,5 ± 0,3 x 10-5 M) como por KCl (CE50 = 2,2 ± 0,2 x 10-5 M) sendo cerca de 2 vezes mais potente frente a este último agente contrátil, sugerindo a participação dos canais de cálcio dependentes de voltagem (CaV) no efeito tocolítico da 7-MF. Para confirmar essa hipótese, foram realizadas curvas cumulativas ao CaCl2 na ausência e na presença da 7-MF e observou-se um deslocamento da curva controle para direita com redução do seu efeito máximo apenas na concentração de 3 x 10-5 M (30%), indicando que provavelmente o bloqueio do influxo de Ca2+ através dos CaV não seja o principal mecanismo tocolítico do flavonoide. Resolveu-se avaliar uma possível participação dos canais de potássio no efeito tocolítico da 7-MF, utilizando o cloreto de césio, um bloqueador não seletivo de canais de K+, e na sua presença a curva controle de relaxamento da 7-MF não foi alterada (CE50 = 3,3 ± 0,6 x 10-5 M), descartando uma modulação positiva dos canais de K+ no efeito tocolítico da 7-MF. Uma vez que as prostaglandinas estão envolvidas em processos fisiopatológicos uterinos e sendo os inibidores de ciclo-oxigenases (COXs) uma das principais classes utilizadas para o tratamento da dismenorreia, resolveu-se avaliar o possível envolvimento da via da COX no mecanismo de ação tocolítica da 7-MF e observouse que na presença da indometacina, um inibidor não seletivo das COXs, a curva controle não foi deslocada (CE50 = 4,8 ± 0,6 x 10-5 M), indicando que a inibição destas enzimas não está envolvida na ação tocolítica da 7-MF. Outra via de relaxamento do músculo liso é a dos receptores adrenérgicos-β. Para avaliar uma possível ativação destes receptores na ação da 7-MF, utilizou-se o (S)-(-)-propranolol, um antagonista dos receptores adrenérgicos-β, e observou-se que não houve alteração da potência relaxante na presença do bloqueador (CE50 = 2,2 ± 0,5 x 10-5 M), indicando que a 7-MF não age por modulação positiva desses receptores para induzir o efeito tocolítico. Como uma das principais vias de relaxamento do músculo liso é a via do óxido nítrico (NO), avaliou-se a participação dessa via no efeito tocolítico da 7-MF e observou-se que na presença de L-NAME, um inibidor não seletivo de sintase do NO (NOS), não houve alteração da potência relaxante (CE50 = 4,4 ± 1,2 x 10-5 M), descartando também essa via no efeito tocolítico da 7-MF. Um passo downstream em comum das vias Gs e do NO é a ação da enzima fosfodiesterase (PDE). Na presença da aminofilina, um bloqueador não seletivo de PDE, observou-se que não houve alteração da potência relaxante da 7-MF (CE50 = 2,8 ± 0,5 x 10-5 M), indicando que provavelmente não é por ativação desta que o flavonoide exerce seu efeito tocolítico. A inibição de vias contráteis também pode ocasionar relaxamento muscular liso, desta forma avaliou-se a participação da via RhoA/Rho cinase (ROCK) no efeito tocolítico da 7-MF. Na presença de Y-27632, um bloqueador não seletivo de ROCK, a curva controle foi deslocada para a esquerda, com aumento da potência relaxante em torno de 22 vezes (CE50 = 1,6 ± 0,7 x 10-6 M), sugerindo que a 7-MF modula negativamente a via ROCK para exercer seu efeito tocolítico. Ainda no mecanismo contrátil, dá-se um destaque para a calmodulina, um dos principais mediadores para a sinalização do Ca2+. Para avaliar a sua participação no efeito tocolítico da 7-MF, utilizou-se o calmidazolium, um bloqueador da calmodulina, e observou-se uma potencialização do efeito relaxante da 7-MF (CE50 = 6,5 ± 1,6 x 10-7 M), em torno de 54 vezes, confirmando a modulação negativa da calmodulina no seu efeito tocolítico. Dessa forma, o mecanismo de ação tocolítica proposto para a 7-MF em ratas é a inibição da via ROCK e da calmodulina.Universidade Federal da ParaíbaBrasilFarmacologiaPrograma de Pós-Graduação em Produtos Naturais e Sintéticos BioativosUFPBOliveira, Fabiana de Andrade Cavalcantehttp://lattes.cnpq.br/2233846820438278Brasileiro, Laiz Aline Silva2019-02-21T15:36:48Z2018-10-252019-02-21T15:36:48Z2018-08-27info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/masterThesishttps://repositorio.ufpb.br/jspui/handle/123456789/13655porAttribution-NoDerivs 3.0 Brazilhttp://creativecommons.org/licenses/by-nd/3.0/br/info:eu-repo/semantics/openAccessreponame:Biblioteca Digital de Teses e Dissertações da UFPBinstname:Universidade Federal da Paraíba (UFPB)instacron:UFPB2019-02-21T15:36:48Zoai:repositorio.ufpb.br:123456789/13655Biblioteca Digital de Teses e Dissertaçõeshttps://repositorio.ufpb.br/PUBhttp://tede.biblioteca.ufpb.br:8080/oai/requestdiretoria@ufpb.br|| diretoria@ufpb.bropendoar:2019-02-21T15:36:48Biblioteca Digital de Teses e Dissertações da UFPB - Universidade Federal da Paraíba (UFPB)false |
dc.title.none.fl_str_mv |
A 7-metoxiflavona apresenta efeito tocolítico por modulação negativa da via Rho cinase e da calmodulina em ratas |
title |
A 7-metoxiflavona apresenta efeito tocolítico por modulação negativa da via Rho cinase e da calmodulina em ratas |
spellingShingle |
A 7-metoxiflavona apresenta efeito tocolítico por modulação negativa da via Rho cinase e da calmodulina em ratas Brasileiro, Laiz Aline Silva Metoxiflavona Tocolítico Útero de rata RhoA/Rho cinase Calmodulina Methoxyflavone Tocolytic Rat uterus RhoA/Rho kinase Calmodulin Substâncias naturais - Ação bioativas Zornia brasilienses Vogel Carrapicho Testes em ratas CNPQ::CIENCIAS BIOLOGICAS::FARMACOLOGIA |
title_short |
A 7-metoxiflavona apresenta efeito tocolítico por modulação negativa da via Rho cinase e da calmodulina em ratas |
title_full |
A 7-metoxiflavona apresenta efeito tocolítico por modulação negativa da via Rho cinase e da calmodulina em ratas |
title_fullStr |
A 7-metoxiflavona apresenta efeito tocolítico por modulação negativa da via Rho cinase e da calmodulina em ratas |
title_full_unstemmed |
A 7-metoxiflavona apresenta efeito tocolítico por modulação negativa da via Rho cinase e da calmodulina em ratas |
title_sort |
A 7-metoxiflavona apresenta efeito tocolítico por modulação negativa da via Rho cinase e da calmodulina em ratas |
author |
Brasileiro, Laiz Aline Silva |
author_facet |
Brasileiro, Laiz Aline Silva |
author_role |
author |
dc.contributor.none.fl_str_mv |
Oliveira, Fabiana de Andrade Cavalcante http://lattes.cnpq.br/2233846820438278 |
dc.contributor.author.fl_str_mv |
Brasileiro, Laiz Aline Silva |
dc.subject.por.fl_str_mv |
Metoxiflavona Tocolítico Útero de rata RhoA/Rho cinase Calmodulina Methoxyflavone Tocolytic Rat uterus RhoA/Rho kinase Calmodulin Substâncias naturais - Ação bioativas Zornia brasilienses Vogel Carrapicho Testes em ratas CNPQ::CIENCIAS BIOLOGICAS::FARMACOLOGIA |
topic |
Metoxiflavona Tocolítico Útero de rata RhoA/Rho cinase Calmodulina Methoxyflavone Tocolytic Rat uterus RhoA/Rho kinase Calmodulin Substâncias naturais - Ação bioativas Zornia brasilienses Vogel Carrapicho Testes em ratas CNPQ::CIENCIAS BIOLOGICAS::FARMACOLOGIA |
description |
Since the 7-methoxyflavone flavonoid (7-MF), one of the major components isolated from Zornia brasiliensis Vogel, showed in vitro tocolytic effect in rats, it was decided to characterize this mechanism. The rat uterus was placed in baths for isolated organ where isotonic and isometric contractions were monitored (n = 5). It was observed that 7-MF relaxed the pre-contracted rat uterus by both oxytocin (OCI) (EC50 = 3.5 ± 0.3 x 10-5 M) and KCl (EC50 = 2.2 ± 0.2 x 10-5 M) being about 2 times more potent compared to this contractile agent, suggesting a participation of voltage-dependent calcium channels (CaV) in tocolytic effect of 7-MF. To confirm this hypothesis, cumulative curves to CaCl2 were performed in the absence and presence of 7-MF and a shift of the control curve to the right was observed, with a reduction of maximum effect only at the concentration of 3 x 10-5 M (30%), indicating that probably blocking Ca2+ influx through CaV is not the main tocolytic mechanism of flavonoid. It was decided to evaluate a possible participation of the potassium channels in tocolytic effect of 7-MF using cesium chloride, a non-selective K+ channel blocker, and in this presence control curve of 7-MF relaxation was not deviated (EC50 = 3.3 ± 0.6 × 10-5 M ), discarding positive modulation of the K+ channels in tocolytic effect of 7-MF. Once prostaglandins are involved in physiopathological uterine processes and the inhibitors of cyclooxygenase (COXs) are one of the main classes used for the treatment of dysmenorrhea so, it was decided to evaluate the possible involvement of the COXs pathway in the tocolytic mechanism of 7-MF and it was observed that in the presence of indomethacin, a nonselective COXs inhibitor, the control curve was not displaced (EC50 = 4.8 ± 0.6 x 10-5 M), indicating that the inhibition of these enzymes are not involved in the tocolytic effect of 7-MF. Another pathway of smooth muscle relaxation is adrenergic-β receptors. In order to evaluate a possible activation of these in the action of 7-MF, used (S)-(-)-propranolol, a adrenergic-β receptor antagonist, was used and it was observed that there was no change in the relaxing potency in the presence of the blocker (EC50 = 2.2 ± 0.5 x 10-5 M), indicating that 7-MF does not act by positive modulation of these receptors to induce the tocolytic effect. As a major route of relaxation of the smooth muscle is the nitric oxide (NO) pathway, it was decided to evaluate the participation of this pathway in the tocolytic effect of 7-MF and it was observed that in the presence of L-NAME, a non-selective inhibitor of NO synthase (NOS), there was no change in the relaxing potency (EC50 = 4.4 ± 1.2 x 10-5 M), also discarding this pathway in tocolytic effect of 7-MF. A common downstream step of the Gs and NO pathways is the enzyme phosphodiesterase (PDE). In the presence of aminophylline, a non-selective PDE, it was observed that there was no change in the relaxing potency of 7-MF (EC50 = 2.8 ± 0.5 x 10-5 M) indicating that it is probably not by its activation that the flavonoid exerts its tocolytic effect. Inhibition of contractile pathways can also lead to smooth muscle relaxation, thus the RhoA/Rho kinase pathway (ROCK) participation in the tocolytic effect of 7-MF was evaluated. In the presence of Y-27632, a non-selective ROCK blocker, the curve was shifted to the left, with an increase in the relaxation potency around 22 times (EC50 = 1.6 ± 0.7 x 10-6 M) suggesting that 7-MF negatively modulates the RhoA/ROCK pathway to exert its tocolytic effect. Still in the contractile mechanism, calmodulin is one of the main mediators for Ca2+ signaling. In order to evaluate its participation in the tocolytic effect of 7-MF used calmidazolium, a calmodulin blocker, and was observed a potentiation of the relaxing effect of 7-MF (EC50 = 6.5 ± 1.6 x 10-7 M), around 54 times, confirming negative modulation of calmodulina in tocolytic effect. Thus, the mechanism of tocolytic action proposed for 7-MF in rats is the inhibition of the ROCK pathway and calmodulin. |
publishDate |
2018 |
dc.date.none.fl_str_mv |
2018-10-25 2018-08-27 2019-02-21T15:36:48Z 2019-02-21T15:36:48Z |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/masterThesis |
format |
masterThesis |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
https://repositorio.ufpb.br/jspui/handle/123456789/13655 |
url |
https://repositorio.ufpb.br/jspui/handle/123456789/13655 |
dc.language.iso.fl_str_mv |
por |
language |
por |
dc.rights.driver.fl_str_mv |
Attribution-NoDerivs 3.0 Brazil http://creativecommons.org/licenses/by-nd/3.0/br/ info:eu-repo/semantics/openAccess |
rights_invalid_str_mv |
Attribution-NoDerivs 3.0 Brazil http://creativecommons.org/licenses/by-nd/3.0/br/ |
eu_rights_str_mv |
openAccess |
dc.publisher.none.fl_str_mv |
Universidade Federal da Paraíba Brasil Farmacologia Programa de Pós-Graduação em Produtos Naturais e Sintéticos Bioativos UFPB |
publisher.none.fl_str_mv |
Universidade Federal da Paraíba Brasil Farmacologia Programa de Pós-Graduação em Produtos Naturais e Sintéticos Bioativos UFPB |
dc.source.none.fl_str_mv |
reponame:Biblioteca Digital de Teses e Dissertações da UFPB instname:Universidade Federal da Paraíba (UFPB) instacron:UFPB |
instname_str |
Universidade Federal da Paraíba (UFPB) |
instacron_str |
UFPB |
institution |
UFPB |
reponame_str |
Biblioteca Digital de Teses e Dissertações da UFPB |
collection |
Biblioteca Digital de Teses e Dissertações da UFPB |
repository.name.fl_str_mv |
Biblioteca Digital de Teses e Dissertações da UFPB - Universidade Federal da Paraíba (UFPB) |
repository.mail.fl_str_mv |
diretoria@ufpb.br|| diretoria@ufpb.br |
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1801842945253441536 |