FIG 6.

Rescue of L-LTP by enhanced CREB activity. (A) Western blot analysis of total protein lysates prepared from hippocampal slices treated with forskolin for 10 min (lanes 10) showing increased pCREB but not CREB compared to that in untreated slices (lanes 0) for both LIMK1^−/− mice and their WT littermates. (B) Summary graph of the Western blots shown in panel A showing a significant increase in the levels of pCREB and CREB in hippocampal slices treated with forskolin (10 min) compared to the levels in untreated slices. (C) Western blot analysis of total brain protein lysates prepared from mice treated with intraperitoneal injections of rolipram (R) or the DMSO vehicle (V) showing that rolipram enhanced pCREB but not CREB levels in both LIMK1^−/− mice and their WT littermates. (D) Summary graph of the Western blots shown in panel C showing a significant increase in the levels of pCREB and CREB in mice treated with rolipram compared to that in mice treated with DMSO. (E to H) Western blot experiments showing that neither forskolin (E, F) nor rolipram (G, H) had an effect on cofilin or phosphorylated cofilin. (I, J) Plasticity induced by HFS (four trains of 100 Hz lasting 1 s each delivered at 20-s intertrain intervals) showing that L-LTP in LIMK1^−/− mice was completely rescued to the level in WT mice by coapplication of 50 μM forskolin (solid line) during HFS (arrows) (I) or rolipram injections (J). Representative traces shown above the graphs were taken at the time points indicated by their respective numbers (1 and 2). Dashed lines indicate 100% and are shown for reference. Error bars represent SEMs. *, P < 0.05; n, number of independent experiments (A to H) and number of animals (I and J).