Caracterização dos receptores P2 em eosinófilos de ratos e possíveis papéis funcionais. / Characterization of the P2 receivers in eosinophils of rats and possible functional papers.
AUTOR(ES)
Anael Viana Pinto Alberto
DATA DE PUBLICAÇÃO
2007
RESUMO
ATP and other nucleotides can be released from cells through regulated pathways or following the loss of plasma membrane integrity. Once outside the cell, these compounds take on new roles as intercellular signaling molecules that elicit a broad spectrum of physiological responses through the activation of numerous cell surface receptors. These nucleotides act on P2 family of receptors that respond by P2X ionotropic receptors and G proteincoupled P2Y receptors. These receptors have been characterized in many rat immune cells. However, there is a lack on yhe literature concerning to the characterization characterization of these receptors in eosinophils. These cells are involved in asthma and pathological and physiological processes. Dispite of that, we investigate, using different techniques, the expression of the P2 receptors in eosinophils. Our first step was to investigate the expression of P2X receptors (ionotropic) using electrophysiology thecnique. The results with the maximum current amplitude normalized gave us the following ranking of agonist potency: ATP>ATPγS>2meSATP>ADP>αβmeATP>βγmeATP>BzATP>UTP>UDP>cAMP, suggesting the presence of P2X2, P2X4. Following the characterization, intracellular calcium measurements were performed. We obtained the follow ranking order of potency: UTP>ATPγS >ADP >UDP>ATP >BzATP >2meSATP >αβmeATP >cAMP >Adenosine >βγmeATP. Moreover, we did some immunofluorescence assays to corroborate our results and our data showed the presence of P2X1, P2X2, P2X4 and P2Y1, P2Y2, P2Y4. Our next step was to verify the participation of these receptors in the in vitro migration of eosinophils by transwell, in these experiments the ATP was able to increase migration, an effect which could be blocked by suramin a general blocker of P2 receptors. Furthermore, we employed a model of rat allergic pleurisy to confirm our findings that P2 receptors are implicated in the migration of eosinophils to an inflammation site. Our results indicate that suramin decreased the number of cells per cavity, showing the participation of the P2 receptors. xiii We have demonstrated for the first time that rat eosinophils express P2X and P2Y and the activation of these receptors can increase migration of eosinophils in vitro and in vivo.
ASSUNTO(S)
fluorescent antibody technique migration imunologia electrophysiology eletrofisiologia eosinófilos migração pleurisia eosinophils pleurisy animais imunofluorescência
