Fig. 1

Effects of GPS on the number of open arm entries (a) and time spent on open arms (b) in the elevated plus-maze test in mice. Mice (ICR, male, 25–30 g) were orally treated with GPS (30, 50, 100, 200 and 400 mg/kg), GP-WX (50 mg/kg), GP-EX (50 mg/kg, positive control) or saline (0.9 %) once a day for 10 days. Mice were exposed to EF stimuli (intensity, 0.6 mA, 1 s every 5 s, periods, 3 min) for chronic stress for 10 days (chronic EF-stressed groups, Stress). The elevated plus-maze test was performed as described under the Methods section. The results are expressed as means ± S.E.M. for 8–10 animals per group. **p < 0.01 compared with control group; ^#p < 0.05 compared with chronic EF-stressed group (one-way ANOVA followed by Tukey’s test); ^§p < 0.05 compared with between the un-stressed groups and stressed groups (two-way ANOVA followed by Tukey’s test)