CNTF and BMP4, but not NGF or BDNF, greatly reduced the number of cells destroyed by toxin treatment indicating that these factors protect retinal neurons from a severe excitotoxic insult.;Interestingly, pharmacological inhibition of the ALK2 receptor prevented neuroprotection by STI1, while activation of ALK2 receptors by bone morphogenetic protein 4 (BMP4) either before or after OGD was effective in decreasing neuronal death induced by ischemia.