Fig. 1

Fatigue- and ME/CFS-like behaviors. After fluoxetine injection for 4 weeks, fatigue-like behaviors were evaluated by both the latency to fall from the drum in rota-rod test (A) and the exercise duration and distance traveled in fatigue rotating wheel test (B). Locomotor activity and immobility duration for 1 h after awakening in the home-cage activity test (C) were assessed. The rota-rod test was then reperformed following 6 weeks of withdrawal of fluoxetine (D). Nesting score was determined according to the degrees to which the mice bit the squares, moved the squares into the corners and nested with the squares in the nest building test (E and F). The latency to paw withdrawal in the plantar test (G) and the time spent in the center and total distance traveled in the open field test (H) were assessed. Forelimb strength per body weight in the grip strength test (I) were assessed. The data are expressed as the mean ± SD (n = 5 or 8/group). *p < 0.05 and **p < 0.01 compared to the saline group