(a) Time course during ginsenoside Rb1 exposure in PC12 cells to phosphorylation of Akt, ERK1/2, SAPK/JNK, or p38 MAPK by Western blot. (b) Time course of phospho-p38 MAPK, phospho-SAPK/JNK, phospho- ERK1/2, or phospho-Akt protein expression during MPP+ exposure in PC12 cells by Western blot. Total protein expression of p38 MAPK, SAPK/JNK, ERK1/2, or Akt was also shown. (c) Effects of ginsenoside Rb1 in MPP+-mediated apoptotic signaling. PC12 cells were pretreated with 10−6 M ginsenoside Rb1 for 1hour and then exposed to 10−4 M MPP+ for 30 minutes. Total protein expression of p38 MAPK, SAPK/JNK, ERK1/2, Akt are also shown. (d) Effects of wortmannin, PD 98059, SB 203580, or SP 600125 on DNA fragmentation assay. PC12 cells were pretreated with 10−7 M wortmannin, 10−5 M PD 98059, 10−5 M SB 203580, or 10−5 M SP 600125 for 1 hour before the addition of 10−6 M ginsenoside Rb1 for 4 hours and then exposed to 10−4 M MPP+ for 24 hours. The experimental values were normalized and presented as a percentage of the vehicle section. The data represent means ± SD of three independent experiments. *P < 0.05 versus MPP+ treated group, **P < 0.05 versus MPP+ and Rb1 treated group.