Effect of Ilantide and interleukin 1 receptor antagonist on survival of cerebellar granule neurons induced to undergo apoptosis. The neurons were allowed to differentiate for 7 days in a high-potassium (40 mM) medium before apoptosis was induced by changing to a low-potassium medium (5 mM). Survival was estimated 48 hours later. (A) The effect of insulin-like growth factor 1 (IGF-1), interleukin 1 receptor antagonist (IL-1Ra) and IL-1β on cerebellar granule neuron (CGN) apoptosis induced by 5 mM KCl. (B) The effect of Ilantide-m on CGN apoptosis induced by 5 mM KCl. (C) The effect of Ilantide-t on CGN apoptosis induced by 5 mM KCl. The results from at least four independent experiments are expressed as mean ± SEM with untreated cultures induced to undergo apoptosis by 5 mM KCl set at 100%. *P < 0.05 and **P < 0.01 compared with untreated cultures induced to undergo apoptosis (one-way analysis of variance followed by Newman-Keuls post hoc test).