P2RX7 and neurodegenerative disease: Recently, P2X7 was found to be a scavenger receptor in the absence of ATP, while excessive ATP abolished P2X7 mediated phagocytosis.377 Given the critical role of phagocytosis in the pathogenesis of neurodegenerative diseases, these results suggest that P2X7 signaling might be beneficial to neurodegenerative diseases in the absence of excessive level of ATP.