Fig. 4

ERK1/2 activation ratios. In the hippocampus (a, b) and striatum (c, d) ERK1/2 activation ratios (pERK/ERK total) were calculated (left panels) as well as ERK1/2 total protein expression (right panels) with data normalized to the WT + SAL group. Data were analyzed by two-way ANOVA and pairwise comparisons corrected with FDR. A significant increase in pERK/ERK total ratio was found in the KO + SAL group compared to the WT + SAL group in the hippocampus and striatum (one-tailed) as predicted. The pERK/ERK total ratio increase in the KO + SAL group was also evident when compared to the WT + Acamp group (two-tailed). In both brain regions, chronic treatment with acamprosate (300 mg/kg) reduced pERK/ERK total ratios in the KO mice to a level not distinguishable from WT + SAL mice (one-tailed) as predicted. There were no differences in the amount of ERK1/2 total in either brain region or between any groups. n = 6 per group and brain region; data shown are LS mean ± SEM; *p < 0.05, †p < 0.1; N.S. = not significant