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. Author manuscript; available in PMC: 2007 May 17.
Published in final edited form as: Neuroscience. 2007 Mar 23;146(2):756–772. doi: 10.1016/j.neuroscience.2007.01.067

Figure 4.

Figure 4

Subcutaneous challenge with whole heat-killed M. vaccae in M. vaccae-preimmunized mice increased serotonin and serotonin metabolite concentrations in the medial prefrontal cortex. Graphs illustrate 5-HIAA, 5-HT, and L-tryptophan concentrations in the left and right hemispheres of each brain region 12 h following subcutaneous injections of vehicle or whole heat-killed M. vaccae in M. vaccae-preimmunized mice (n = 8-9). Abbreviations: 5-HIAA, 5-hydroxyindoleacetic acid, 5-HT, 5-hydroxytryptamine; Mv, s.c. challenge with heat-killed M. vaccae, Sal, s.c. challenge with saline vehicle; TRP, L-tryptophan. For additional abbreviations, see Fig. 1 legend. *P ≤ 0.05, compared to M. vaccae-preimmunized, vehicle-injected controls based on multifactor ANOVA with repeated measures analysis within each brain region.