Membrane depolarization represses the SUMO protease Senp1. (a) The relative mRNA levels of Senp1 in cortical neurons was determined by qRT-PCR following treatment with vehicle (Control), 25 mM potassium chloride (KCl) for 2 hours (hrs), 25 mM KCl for 24 hrs, 60 mM KCl for 2 hrs, or 60 mM KCl for 24 hrs. Graphs indicate three independent biological replicates. Error bars represent one standard deviation from the mean. *(p < 0.05). p value was determined using two-tailed unpaired t test. (b) Western blot analysis of Senp1 expression level following neuronal depolarization in cortical neurons. Total proteins were extracted from cortical neurons after 2 hrs treatment with 60 mM KCl and control treatment. Actin was used as loading control.