METH preconditioning enhanced Akt but not JNK activation in response to 6-OHDA.

MN9D cells were treated with a sub-lethal concentration of METH for 24 hr and then exposed to 100 µM 6-OHDA for 20 min before the cells were lysed at 15 min, 30 min, 1 hr, 6 hr, and 24 hr post 6-OHDA. (A) METH decreased pAkt levels as shown for the 15 and 30 min time points. (B) METH preconditioning potentiates Akt activation in response to 6-OHDA and no effect was seen on total Akt levels. (C) Quantification of pAkt compared to total Akt in 4 independent experiments. (D, E) METH preconditioning has no effect on basal or 6-OHDA induced phosphorylation of JNK. α-tubulin was used to control for protein loading. Data are means ± SEM (N = 3). *p<0.05 compared to control.