Figure 3.
DHPG at concentrations that induce LTD and activate the ERK cascade, but not p38 MAPK, in CA1. Representative Western blots are shown of untreated [ACSF or basal (B)] or treated [100 μm DHPG (D), 5 min] hippocampal slices. Quantitative group data of each condition are described below. The number of slices (n) is indicated on each bar. Conditions are indicated below each bar (D 50 and D 100 indicate 50 and 100 μm DHPG, respectively, for 5 min). *p < 0.01, statistically different from condition control. A, DHPG-induced ERK phosphorylation does not rely on NMDAR activation or action potentials and is blocked by U0126. B, DHPG-induced ERK phosphorylation is blocked by the group 1 mGluR antagonists LY367385 (LY) and MPEP. C, DHPG increases the phosphorylation of the ERK substrate RSK1 and is blocked by U0126. Representative Western blots show control (C) extract (phorbol ester-treated HeLa cells) and hippocampal slices (basal) or DHPG treated as indicated. D, In contrast, DHPG treatment does not result in an increase in phosphorylated p38 MAPK/total p38 MAPK. Dashed lines indicate 100% of basal.