Time dependent antisense-NR2B effects.A, Antisense-NR2B injection leads to a time-dependent decrease in the amount of hippocampal NR2B protein that is most significant on day 3 after injection (35% reduction antisense-NR2B/vehicle; number of animals: n = 16;p = 0.002). Scrambled-NR2B controls do not show a significant decrease in the amount of NR2B protein on either day 3 or day 4. B, Spatial learning performance, assessed by four trials per day for 4 d in a Morris water maze hidden platform task, shows a significant time-dependent difference between antisense-NR2B-treated animals and both vehicle- and scrambled-NR2B-treated controls (p = 0.058 by repeated measures ANOVA) that is most pronounced on day 2 of training, which corresponds to day 3 after injection (p = 0.02, antisense-NR2B/scrambled-NR2B;p = 0.035, antisense-NR2B/vehicle, by ANOVA with Fisher's PLSD post hoc test). Distance units shown are in a linear, calibrated arbitrary tracking unit.