Involvement of P2X7 receptors in the hypoxia-induced death of rat retinal neurons.

PURPOSE. To investigate the hypoxia-induced death of rat retinal neurons and to determine whether P2X7 activation is involved in this type of neuronal death. METHODS. Cultured retinal neurons from fetal rats were used. The effects and time course of various degrees of hypoxia (1%–5% O2) in the death of retinal neurons, were examined. The effects of P2X7 antagonists, oxidized adenosine triphosphate (oxidized ATP; 30 –100 M), and brilliant blue G (BBG; 100 nM–10 M) on hypoxia-induced neuronal death, including apoptosis, were assessed by using trypan blue exclusion, TUNEL assays, and cleaved caspase-3 immunoreactivity. Immunocytochemical analysis was performed to determine whether these neurons express P2X7 receptors. The effects of P2X7 receptor stimulation, induced by the P2X7 agonist benzoylbenzoyl-ATP (BzATP), on neuronal viability and intracellular Ca 2 levels ([Ca 2 ]i) were examined.