Fig. 5.

PKA activity mediates for cholera toxin-induced differentiation in C6 cells. (A and B) C6 cells were incubated with 10 ng/ml cholera toxin for the time indicated. (A) PKA activity was measured. (B) Total protein was extracted and blotted with antibodies against p-CREB and CREB. (C and D) C6 cells were pretreated with 10 μM PKI for 2 h and then treated with 10 ng/ml cholera toxin for an additional 48 h for morphology of C6 cells (C) (original magnification: ×200) and for Western blotting to evaluate GFAP, cyclin D1, and CREB phosphorylation (D).