Memory formation requires p38MAPK activity in the rat hippocampus.

Using the specific inhibitor of p38MAPK, SB203580, we show a direct involvement of this protein kinase in short- and long-term memory. When given into the CA1 region of the rat dorsal hippocampus immediately, but not 30 or 120 min after training in a one-trial inhibitory avoidance task, SB203580 blocked short- and long-term memory formation. The SB203580 inactive analog, SB202474, had no effect whatsoever. Learning of the avoidance task was accompanied by an immediate and transient increase in hippocampal p38MAPK phosphorylation. No change in p38MAPK phosphorylation was detected in control animals that only received the electric foot-shock associated with the learning paradigm. Therefore, formation of short and long-term memory for inhibitory avoidance requires p38MAPK activation in the rat hippocampus.