A função do sistema purinégico na modulação neural da pressão arterial

João Paulo de Pontes Matsumoto, Merari de Fátima Ramires Ferrari, Monica Akemi Sato, Cristiana Akemi Ogihara, Luiz Carlos de Abreu

Resumo


Introdução: A adenosina e o ATP são substâncias encontradas em abundância nas áreas de controle da pressão arterial. Muitos estudos foram realizados com o propósito de elucidar a função desse sistema nos núcleos do tracto solitário, que constitui o primeiro sítio de integração das aferências do sistema cardiovascular. Objetivo: Descrever os mecanismos e sítios de ação da adenosina e ATP nos núcleos do tracto solitário (NTS) e as diferentes respostas geradas em função de sua estimulação. Métodos: revisão bibliográfica entre os anos de 2006 e 2007 através do portal Medline/Pubmed (via OVID), delimitada em estudos datados entre 1976 e 2006. Resultados e Discussão: Muitos estudos indicam que o ATP atua via receptores purinérgicos P2x no NTS, causando bradicardia via inibição do simpático e estimulação do parassimpático em locais específicos. A adenosina estimula principalmente os receptores A2a e produz preferencialmente vasodilatação nos membros posteriores por meio da ativação da medula adrenal e vasodilatação β-adrenérgica provocando diminuição da pressão arterial. A adenosina e o ATP atuam no NTS como neurotransmissores de ativação rápida, de neuromoduladores e de co-transmissores ligados à liberação do glutamato oriundo das aferências vagais, predominantemente causando hipotensão. Conclusão: O sistema purinérgico atua no NTS ocasionando bradicardia via modulação dos sistemas simpático e parassimpático.

Palavras-chave


Núcleos do tracto solitário; Adenosina; ATP

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