Fig 5. (a) The effects of two specific inhibitors of P2Y receptors (suramin and PPADS) on neurite outgrowth of differentiating N2a cells. (b) The effects of specific inhibitors of MEK/ERK and PI3K/Akt pathways (U0126 & PD98059; and LY294002, respectively) on neurite outgrowth of differentiating N2a cells. NGF (50 ng/mL) was used as positive control and medium only with no treatment was used as control. Aqueous (AE) and ethanol extracts (AE; 20 μg/mL) were tested to compare with uridine. Values are mean ± SD from three independent experiments. Different alphabets represent significant differences between samples. *p < 0.05 significantly lower relative to group without inhibitor treatment.