Fig. 1. Phosphorylation of histone H3 is induced in the hippocampus by stimulation of DA, mACh and GLU receptors. (A) Schematic representation of the histone H3 N-terminal tail. The key residues within the H3 tail where covalent regulatory modifications occurs are indicated. These include acetylation at lysines and phosphorylation at conserved serine residues. (B) Immunohistochemistry on mouse hippocampal cryosections using P.H3 antibody. In order to stimulate DA, mACh or GLU receptors, mice were injected with SKF82958 (5 mg kg^–1), pilocarpine (300 mg kg^–1) or kainic acid (35 mg kg^–1), respectively, and sacrificed after15 minutes, 1 hour or 3 hour. Control animals, indicated with the symbol (–), were injected with saline solution. (C) Phosphorylation of histone H3 in the DG and in the CA3 after stimulation of DA, mACh and mGLU receptors. (D) Quantification of the data in (A,B). A total of six animals were analysed from three independent experiments. Cell counts were performed under the light microscope. Statistical comparisons were performed with one-way ANOVA on the total number of positive cells (independently from the intensity of the staining that is indicated on the graph in gray and black) followed by Bonferroni's post hoc test. ^***, P<0.001; ^**, P<0.01. Scale bars, 300 µM (B); 70 µM (C).