Figure 4. Axonal degeneration induced by ammonia is mediated by calpain. (A) Cultured cerebellar granule cells were treated with 2 mM ammonia for 24 h with or without ALLM, ZVAD, or AR-A014418, and observed by microscopy. Neurons were subjected to immunocytochemistry with βIII-Tubulin (βIII) and Hoechst for nucleus staining. White arrows show the beading puncta. Neurite fragmentation (B) and axonal beading (C) were quantified as in Figure 1. Data are means ± SEs from at least three independent experiments; * p < 0.05 vs. Ctrl. Scale bar, 20 μm.