Western blot analysis of cultured astrocyte cell lysates treated with forskolin at various concentrations for 3 hr. Forskolin induced a dose-dependent increase in both the neuregulin (A) and GFAP (B) expressions by astrocytes. The concentrations of forskolin onA and B were as follows (in μm): lane 1, 0; lane 2, 0.3; lane 3, 1; lane 4, 3; lane 5, 10; lane 6, 30, respectively. The positions of molecular mass markers (in kilodaltons) are shown to theleft of A.