Fig. 4.
c-Fos induction in the hippocampus and amygdala following fear conditioning depends on M3-muscarinic receptor phosphorylation. Wild-type (WT) or M3R-KI (KI) mice were subjected to fear conditioning training, and the animals were killed by cardiac perfusion of fixative solution 30 or 120 min after training. The brain was then dissected and sectioned before staining for c-Fos expression. Basal conditions represent animals that had not undergone fear conditioning training. (A) Immunofluorescent staining for c-Fos expression in the dentate gyrus of the hippocampus. (B) Immunofluorescent staining for c-Fos expression in the CA3 region of the hippocampus. (C) Immunofluorescent staining for c-Fos expression in the amygdala. Graphs represent quantification of the immunofluorescent staining showing means ± SE (n = 4). *, P < 0.05 (t test). c-Fos appears as the red label and nuclei are stained blue using DAPI.