Fig. 1.

Experimental groups and time lines. In protocol 1, the effects of the PRR agonists on daily activity were assessed in the LabMaster system. In protocol 2, the effects of MDP and FK565 alone and the combination of MDP or FK565 with the higher dose of LPS (0.83 mg/kg) on sickness and central c-Fos expression were evaluated. In protocol 3, the effects of MDP and FK565 alone and the combination of MDP or FK565 with the lower dose of LPS (0.1 mg/kg) on sickness, mood and inflammation-related parameters were analyzed. Time zero represents the time of injection and was consistent across all experiments. Abbreviations: CORT = corticosterone, KYN/TRP = kynurenine/tryptophan ratio, FST = forced swim test, OF = open field, Temp = temperature, TST = tail suspension test.