Ablation of GR protein expression in neurons of the adult brain upon tamoxifen treatment. Vibratome-sections of mice homozygous for a conditional GR allele (GRflox) and heterozygous for the CaMKCreERT2 transgene (GRCaMKCreERT2 mice) have been analyzed by immunohistochemistry. GR protein is expressed in vehicle-treated GRCaMKCreERT2 mice (A, D, G, J, M), whereas loss of GR expression upon tamoxifen treatment is observed in brain regions (B, E, H, K, N) that display strong CreERT2 expression (C, F, I, L, O). The analyzed GRCaMKCreERT2 mice harbor two copies of the CaMKCreERT2 transgene. Depicted are brain regions that have been identified as target regions using ROSA26 reporter mice and/or show strong GR expression in controls: cortex (A-C), CA1 region of the hippocampus (D-F), dentate gyrus (G-I), PVN (J-L) as well as central (ceA) and basolateral amygdala (blA) (M-O). The animals were injected with 1 mg tamoxifen or vehicle twice a day for five consecutive days and sacrificed ten days after the last injection. In addition, Cre transgenic mice were injected with tamoxifen 12 hours before analysis to obtain a nuclear staining for the CreERT2 fusion protein.