Figure 2.

ERK activity is required for the upregulation of translational proteins in LTP. A, Immunoblots of CA1 lysates, from slices frozen 30 min after stimulation, showed that the MEK inhibitors PD98059 (50 μm) and U0126 (20 μm) prevented the HFS-induced increases in the expression of the TOP mRNA products eEF1A, eEF2, rpS6, and PABP1. The asterisks indicate p < 0.05 compared with control (Con), and sample immunoblots are shown above each summary graph. All group values of n were ≥6. B, In the presence of an MEK inhibitor, HFS produced only a decremental potentiation. The rate of decay for slices treated with 50 μm PD98059 or 20 μm U0126 (both values of n = 5) was similar to that observed previously when protein synthesis or mTOR activity was blocked (Tsokas et al., 2005), whereas LTP was stable for 2 h in vehicle-treated controls (Veh) (n = 5). The traces show superimposed fEPSPs recorded during the baseline period and 2 h after HFS (arrows) in a vehicle-treated control slice (left) and a slice treated with PD98059 (right).