Fig. 1.

Glutamate induces Ser¹³³ CREB phosphorylation and Fos protein in primary striatal cultures.A, Immunoblots of rat primary striatal cultures were treated with glutamate (50 μm) for 5 min to 10 hr (times indicated above theblots). P-CREB, CREB was phosphorylated 5 min after the addition of glutamate and remained phosphorylated for at least 5 hr. CREB, An antiserum that is indifferent to the state of phosphorylation of CREB showed that the protein levels of CREB were not changed. Fos, Fos protein was induced 2–5 hr after the addition of glutamate. CREB and Ser¹³³CREB had a molecular weight of ∼43 kDa, whereas Fos protein was slightly below the 60 kDa protein marker. B, Primary striatal cultures were exposed to glutamate (50 μm) for 1–15 min, at which time glutamate was removed from the cells. All cells were harvested 15 min after the addition of glutamate. Immunoblots were developed with Ser¹³³ CREB antiserum (Ginty et al., 1993). All treatments are shown in duplicates.