(A) Schematic representing the floxed locus for the generation of Nod1f/f mice. (B) Effect of intestinal epithelial Nod1 deletion on behavior: NOR task, L/D box and OFT (N = 7–12), serum corticosterone and hippocampal mRNA expression levels of stress genes (GR, MR) and serotonin signaling (5HTr1a, 5HTr2c, Tph1 and Sert); (C) Ileum and colon basal short circuit current [Isc], basal conductance [G] and FITC dextran flux assessment (N = 6–9) as well as 5HTr1a, 5HTr2c, SERT and Tph1 mRNA expression levels (N = 6–8). Data are presented as mean ± SEM. (*P < 0.05; **P < 0.01, ***P<0.001 unpaired Student’s t-test).