The calpain inhibitor, calpeptin, rescues SGN neurites from growth inhibition by depolarization. A. Cumulative percent histograms of SGN neurite lengths from cultures maintained in NT-3, NT-3+30K, or NT-3+80K with or without calpeptin (Calp,10 μM) as indicated. Each condition was repeated three times. NT-3+30K and NT-3+80K are significantly different (p<0.05) from NT-3+30K+Calp and NT-3+80K+Calp, respectively, by Kruskal-Wallis ANOVA on Ranks followed by a Dunn’s post-hoc comparison. n=cumulative number of SGNs scored for each condition B–C. Representative images of spiral ganglion cultures maintained in NT-3+30K or NT-3+30K+Calp (B) and NT-3+80K or NT-3+30K+Calp (C) for 48 h and labeled with anti-NF-200. Scale bar=100 μm.