Extracellular ATP induces retinal photoreceptor apoptosis through activation of purinoceptors in rodents

Abstract

We have previously demonstrated that photoreceptors express P2X7 purinoceptors. These excitatory receptors are activated by extracellular adenosine 5′-triphosphate (ATP) and have been implicated in neurodegeneration in other parts of the central nervous system (CNS). In this study we examined whether extracellular ATP could contribute to photoreceptor degeneration in rodents through excessive activation of P2 purinoceptors. Intravitreal injection of high concentrations of extracellular ATP into normal rat eyes induced extensive and selective apoptosis at photoreceptors within 18 hours of injection. Five days after injection the outer nuclear layer was severely degenerated and electro-retinog..