Figure 8.

BDNF and EGF stimulate calpain-mediated spectrin degradation in cultured cortical neurons. Cortical neurons were pretreated with vehicle or the MAP kinase inhibitor PD98059 (25 μm) for 15 min before being treated with BDNF (50 ng/ml) or EGF (20 ng/ml) for 60 min. Cell lysates were processed for Western blotting with spectrin antibodies and actin antibodies (as a loading control). Levels of the 145–150 kDa calpain-specific breakdown products were quantified and expressed as percentage of values found in control cultures. Results are means ± SEM of six independent experiments. *p < 0.01 compared with control; ^‡p < 0.05 compared with BDNF- or EGF-treated samples.