Figure 4.

Survival effect of DADLE on PC12h and F11 cells as analyzed by MTT assay. (A) PC12h cells (10,000 cells) were plated in 96 well plates and differentiated for three days with 100 ng/mL NGF. After three days, the medium was removed, cells were washed and re-fed with serum free medium (without NGF) and treated with the respective compounds for another 48 h. MTT assay was performed as described in Materials and Methods; (B) F11 cells (10,000 cells/well) were plated in 96-well plates and differentiated for 72 h with 0.5 mM db-cAMP with or without 50 ng/mL NGF. Cells were also differentiated in the presence of db-cAMP, NGF and K252a. Cells were pretreated with 100 nM K252a for 30 min before addition of 50 ng/mL NGF. After 72 h of differentiation the medium was removed and cells were washed and re-fed with serum free medium with or without 1 μM DADLE for 48 h. As a positive control cells were continued to differentiate in db-cAMP in the presence or absence of NGF for a total of five days. After a total of five days in culture the cells were harvested and MTT assay was carried out as described in Materials and Methods. Data are expressed as mean ± SEM of three independent experiments done in six replicate wells for each treatment. * p < 0.05.