Neurons were treated for 20 min with 0–10 μM of DA, H2O2 or SKF R-38393, and Western blot analyses were conducted to probe for p-ERK1/2 [A], p-JNK [B] and p-p38 MAPK [C]. D. Time-course of p-ERK1/2 expression in striatal neurons treated with 10 μM of either DA or SKF R-38393. E. Time-course of p-ERK1/2 kinase activity in striatal neurons treated with 10 μM of either DA or SKF R-38393. F. Time course of p-MEK expression in striatal neurons treated with 10 μM of either DA or SKF R-38393. Equal levels of ERK2 expression were confirmed by Western blot (Data not shown). Blots were scanned and values expressed as the average ± S.E.M of three experiments (n=3). p<0.05 (*), represents the result of paired Student’s t test with 4 degrees of freedom for the corresponding DA treatment group; p<0.05 (#) and p<0.01 (##), represent the result of paired Student’s t test with 4 degrees of freedom for the corresponding vehicle control group.