CHARACTERIZATION OF THE LONG-LASTING ACTIVATOR PROTEIN-1 COMPLEX-INDUCED BY KAINIC ACID TREATMENT

Kainic acid is known to induce seizures, neuronal damage and cell loss in the rat hippocampus. Our laboratory has shown that a single kainic acid injection elicits acute increases of activator protein-1 DNA-bin ding activity and this activity stays at an elevated level for 2 weeks after kainic acid injection. However, some pathological changes such as messy fiber sprouting do not occur until 2-3 weeks after the kainic acid injection and the specific transcription factors regulating the long-term events after kainic acid treatment are not clear. To determi ne the involvement of activator protein-1 transcription factors in the long-term events after kainic acid treatment, gel mobility-shift and Western blot analyses were used. The results showed that two activator protein-1 complexes with different mobilities occur during the acute stage. However, only the faster-migrating complex as well as the 35-37 -kDa fos-related antigen and Jun-D proteins were seen during the late stage. These results suggest that different activator protein-1 comple xes exist at different stages after convulsions and that they regulate ensembles of different genes. (C) 1997 Elsevier Science B.V.