Combined effects of maternal separation stress and social defeat stress on the transcription of genes involved in endorphin and neurotrophin signaling in the amygdala. Quantification of real-time PCR data using primers specific for MOR1 (A), KOR1 (B), DOR1 (C), PENK (D), PDYN (E), POMC (F), BDNF (G), and CREB (H). Black bars show data from control mice not subjected to SDS; grey bars show data from mice exposed to SDS. Δ indicates significant main effect of SDS, * indicates a significant main effect of MSS, ‘x’ denotes significant MSS by SDS interaction by two way ANOVA. N = 8 mice per group.