DAP induced HSP70 expression in rat pheochromocytoma PC12 cells. (A and B) PC12 cells were stimulated with (A) 20 µM DAP for 2, 4, 8, 12 h or (B) various concentrations of DAP for 12 h. Total cellular protein were extracted and subjected to western blotting probed with an anti-HSP70 (70 kDa) antibody. Equal protein loading was confirmed by β-actin (45 kDa). DAP, daphnetin; HSP, heat shock protein.