Resumo

Adenosine is a neuromodulator implicated in nervous system development and plasticity. The function of adenosine depends mainly on a balance between activation of inhibitory A1 and facilitatory A2A receptors. Previously we had shown the expression of these receptors in the visual system: being A1 more evident in the early and A2a in the late stage of superior colliculus development. Therefore, we investigated the effect of A1 and A2a receptors blockade upon the development of retinotectal circuitry. For this purpose, Lister Hooded rats at PND7 were submitted to a subpial ELVAX implant containing DMSO (vehicle), DPCPX (1 µM – A1 receptor antagonist) or SCH 58261 (1 µM - A2a receptor antagonist). Animals were maintained with treatment at different stages of development. In each group, animals were processed for western blotting analysis to evaluate A1 and A2a contents. Our data showed that DPCPX- induced A1 receptor blockade during the critical period leads to a slight increase in A1 expression, mainly between PND7 to PND28 compared to DMSO-treated rats. On the other hand, A2a receptor inhibition, between PND7 to PND42, after the critical period, induced a significant decrease in the A1 content compared to control. The blockade of both A1 and A2a receptors also modulated A2a receptor expression. Previously we demonstrated that adenosine receptors blockade leads to a disruption on retinotectal topography. Herein we showed a correlation between A1 and A2a receptors in the retinotectal system. Taken together, these data suggest that an intrinsic regulation between these receptors could be important to the proper synaptic stabilization in the retinotectal pathway.