The extracellular signal-regulated kinase (ERK1/2) is one of the downstream kinases of NMDA receptors in the hippocampus, controlling the neuroplasticity underlying memory processes and neuronal development (Krapivinsky et al., 2003). U0126, a selective inhibitor of MAPK kinase (MEK1/2), the immediate upstream activator of ERK1/2, inhibits ERK1/2 activation in acute slices (Giovannini et al., 2003). U0126 (2.5 μM) did not affect control γ power (P > 0.05, vs. baseline, n = 8) or the suppression of γ oscillations by ethanol (example in Figure 6C). In the presence of U0126, 50 mM ethanol caused a 27.5 ± 12.0% (P < 0.01, vs. U0126 baseline, n = 8) and 100 mM ethanol a 53.6 ± 7.4% (P < 0.001, vs. U0126 baseline, n = 8) decrease in γ power, neither of which was different from that in the absence of U0126. (Figure 6D). These results suggest that ERK activation is not required for the ethanol-induced suppression of γ oscillations.
