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Degree Level: Mestrado
Title: Fisiologia do musculo liso traqueal de cobaias "in vitro" : efeitos da indometacina e do azul de metileno
Author: Marques, Maria Julia, 1961-
Advisor: Meirelles, Urbano Morato Ferraz, 1937-
Abstract: Resumo: 1. A modulação endógena das respostas ao agonista exógeno cabacol foi demonstrada, não apenas pelo uso de inibição específica, como também sem inibidor da ciclooxigenase, em condições isotônicas que revelam o tono intrínseco da cadeia traqueal. 2. Na musculatura lisa traqueal, as respostas relaxantes ao nitroprussiato de sódio são inibidas pelo azul de metileno, tanto em presença como em ausência do sistema intrínseco, sugerindo que os mecanismos envolvidos no relaxamento da musculatura respiratória pelo nitrocomposto são análogos aos já descritos no músculo liso vascular. 3. O azul de metileno não altera as respostas contráteis ao carbacol, mas as contrações aos estímulos mecânicos estão inibidas. Esses resultados são compatíveis com a hipótese de que haja um componente comum a ambos sistemas em que o grupo heme esteja implicado na ativação da guanil-ciclase e também essencial na catálise da reação de produção de prostaglandina G

Abstract: The ¿in vitro¿ analysis of the guinea pig tracheal smooth mulcle behavior hás revealed that its responses to the action of agonists is modulated by endogenously produced prostaglandins (OREHEK et al., 1975). In our experimental conditions, the isotonic contractions after intermittent standard mechanical stimulation cannot be abolished by simple washings of the preparation. Contrarywise, the contractile responses are cumulative until a well defined level of contraction is reached. If at any point the muscarinic agonist carbachol is added to the prepatation, a higher, or even the maximum level of contraction can be attained. If carbachol is removed from the organ bath, only partial relaxation can be achieved, to a level similar to that of the mechanically stimulated preparation. Complete relaxation can be afforded by activelly stimulating beta adrenergic receptors, or, for example, by sodium nitroprusside. The responses to high concentrations of carbachol ate modulated physiologically, a process that can be prevented by treating the preparation with the nonsteroid anti-inflammatory agent indomethacin. The pharmacological effects of nitroprusside and methylene blue on this preparation were studied in the search for analogous actions as those exerted by these agents, alone or combined, in the vascular smooth muscle. The physiological antagonism between carbachol and nitroprusside is dosedependent but tachyphylaxis to the repetitive challenging with nitroprusside could not be demonstrated. Methylene blue, proposed as an inhibitor of the activation of guanylate-cyclase by nitric oxide, the intermediary active component of sodium introprusside, has additional inhibitory properties on the intrinsic system that modulates the tonus of the guinea pig tracheal muscle
Subject: Músculos respiratórios
Language: Português
Editor: [s.n.]
Date Issue: 1987
Appears in Collections:IB - Tese e Dissertação

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