Distribution of immunoreactivity for P2X3, P2X5, and P2X6-purinoceptors in mouse retina.

Previous findings have shown that P2X-purinoceptor-mediated signaling pathways regulate the release of ACh in the retina. We previously reported the existence of immunoreactivity for P2X1-, P2X2-, P2X4-, and P2X7-purinoceptors in mouse retina and speculated that P2X2 and P2X7-purinoceptors may modulate the activity of cholinergic amacrine cells. In the present study, we used an immunohistochemical technique to examine whether P2X3-, P2X5, and P2X6-purinoceptors are also important for the modulation of cholinergic amacrine cells in mouse retina. Immunoreactivity for P2X3-, P2X5-, and P2X6-purinoceptors was observed in mouse retina. Immunoreactivity for P2X3- purinoceptors was observed in the dendrites of cholinergic amacrine cells. Immunoreactivity for P2X5-purinoceptors existed in the soma of cholinergic amacrine cells. P2X6-purinoceptor immunoreactivity was not colocalized with the cholinergic amacrine cells. We concluded that, among the three P2X-purinoceptors that were examined, P2X3-purinoceptors seem to affect the function of cholinergic amacrine cells in the mouse retina.