Figure 4.

pMeCP2 in the LHb is induced by chronic but not acute imipramine treatment after chronic social defeat stress. a, C57BL/6 mice were subjected to 10 consecutive days of social defeat stress and then given acute imipramine (27 d of Veh injections followed by imipramine injection on day 28) or chronic imipramine (28 d). The control group was not subjected to defeat but received 28 d of Veh. pMeCP2 immunoreactivity was analyzed in the NAc, prelimbic cortex (PLC), cingulate cortex (Cing. cortex), hippocampus (Hipp.), and LHb 2 h after the final injection. Overlay of pMeCP2 (red) in the LHb and nuclear Hoechst stain (blue) is shown to highlight the subpopulation of pMeCP2-positive cells. Dotted lines indicate the borders of the LHb and the medial habenula (MHb). b, Inset image of the dashed white box in a of pMeCP2 immunoreactivity in the LHb. c, Quantification of pMeCP2 immunoreactivity in the LHb after Veh or acute or chronic imipramine treatment. n = 8–9 mice per group. Scale bars: a, 10 μm; b, 40 μm. For c, *p < 0.05 compared with Veh.