Expression of the P2X 7-receptor subunit in neurons of the rat retina

Abstract

Despite the considerable evidence of signaling by extracellular nucleotides in other sensory systems, few studies have been undertaken in the eye. Molecular and immunohistochemical methods were used to demonstrate the expression and cellular localization of the P2X 7 receptor subunit in the retina and choroid. RT-PCR was used for the detection of P2X 7 subunit mRNA in the rat of different postnatal developmental stages (P23–P210) and revealed the presence of P2X 7-mRNA in the retina, but not in the choroid. In the adult rat retina, immunolabelling for P2X 7 was detected in a number of cells in the inner nuclear layer (INL) and ganglion cell layer (GCL), suggesting different types of amacrine cells and ganglion cells. These results demonstrate for the first time the expression of the P2X 7 receptor in the mammalian retina and furthermore in distinct neuronal cell populations. Our data suggest that extracellular ATP may provide both neuromodulatory and trophic influences on visual processing.