Fig. 7

Kynurenine/tryptophan ratio and hippocampal neurotoxic kynurenine metabolite ratio are up-regulated in response to peripheral LPS. The kynurenine/tryptophan ratio was measured at 24 h following LPS injections in the (a) dorsal hippocampus, (b) ventral hippocampus, (c) central amygdala, and (d) nucleus accumbens. Metabolite ratios of 3-hydroxykynurenine/kynurenic acid (3-HK/KA, neurotoxic ratio, left panel) and 5-hydroxyindoleacetic acid/serotonin (5-HIAA/5-HT, serotonin turnover, right panel) were measured 24 h post LPS in the (e) dorsal hippocampus, (f) ventral hippocampus, (g) central amygdala, and (h) nucleus accumbens. Data represent sample means ± SEM, n = 7–12 samples/group. ^# p < 0.1–0.05; *p < 0.05–0.01; **p < 0.01–0.001; ***p < 0.001