Primer sequences for qPCR. Primers were custom designed and validated by PrimerDesign Ltd. (Southampton, UK). Figure S1. The effect of a low dose of LPS on locomotor activity at 24 and 48 h post-challenge in naïve mice. Naïve animals were subjected to a single dose of LPS (0.1 or 0.5 mg/kg) or vehicle injection and were tested at 24 or 48 h post-injection. (A) Neither the resting time was unaltered by the treatment in the TruScan open field nor (B) rearing in the novel cage test for the total number of rear. (C–E) Aggressive behaviour was also unaltered. Data are mean ± SEM, two-way ANOVA throughout. Figure S2. (A, B) Body weight in the chronic stress experiment. Experimental groups were balanced upon baseline mean values of body weight measured 7 days prior the start of the chronic stress experiment and LPS challenge. Mice exposed to chronic stress had a significant reduction in body weight as compared with baseline measurements (*p 0.05, one-way ANOVA and post hoc Tukey test; see the text). (F) Naïve and stressed animals (10 days) were challenged with a single dose of LPS (0.1 mg/kg) or vehicle (saline) and tested 24 h thereafter in a novel cage test for total number of rears (see the text). Data are mean ± SEM. No differences between the groups were observed. Figure S3. (A–C) Baseline behaviour in a resident-intruder test. Experimental groups were balanced upon baseline mean scores of behaviours in a resident-intruder test that were studied 7 days prior the experimental chronic stress procedure and LPS challenge. Mice had similar mean measures of (A) latency to attack, (B) number of attack and (C )duration of crawl over behaviour. (p > 0.05, one-way ANOVA and post hoc Tukey test; see the text). (D) The latency to attack after the chronic stress was not significantly altered.