Figure 3.

MAPK activity undergoes a circadian oscillation in the hippocampus. Phosphorylation of MAPK oscillates in the hippocampus on the diurnal cycle. Mice were maintained on a 12-h light/12-h dark cycle for at least 10 d before experimentation. Mice were sacrificed every 4 h. Sacrifices made during the dark cycle were performed under red light. Pooled hippocampal extracts were evaluated by Western blot for phospho-p42MAPK expression. Phospho-P42/MAPK was normalized to actin expression in the hippocampus during the diurnal cycle (n = 3 animals per time point). ANOVA error bars, SE (Bonferroni’s Multiple Comparison Test for post hoc analysis). (Reprinted from Eckel-Mahan et al. 2008.)