Treatment effect on the travelled distance on days 2, 8, 15 and 22. Travelled distance was measured for 30 min, half hour after treatment on days 2, 8, 15, 22. Data are presented as mean ± SD, with 8 rats per group (one-way ANOVA followed by Tukey test). Total degree of freedom = 39. p < 0.05: no symbol, * p < 0.05, ** p < 0.01, *** p < 0.001.