After treatment of cortical neurons with AF, the phosphorylation of ERK was determined by Western blotting. a Phosphorylation of ERK was increased by AF treatment in a time- (left) and dose-dependent manner (right). b ERK phosphorylation was reduced by treatment with MEK inhibitors, PD98059 and U0126. In cortical neurons, treatment with AF (20 μL/mL) AF for 20 min showed a significant increase in the ERK phosphorylation whereas the application of PD98059 or U0126 reduced its phosphorylation. *p < 0.05, versus CTL cells (CTL); ##p < 0.01, versus AF and DMSO treated cells (DMSO); ###p < 0.001, versus DMSO-treated cells (DMSO). c After treatment of cortical neurons with AF, the phosphorylation of GSK-3α and 3β was determined by Western blotting. Phosphorylation of GSK-3 was increased by the treatment of AF. A representative blot (left) and statistical bar graph (right). *p < 0.05, **p < 0.01, versus CTL cells (CTL).