The effects of the traditional Chinese (Kampo) medicines, Hochu-ekki-to, Yoku-kansan and Saiko-ka-ryukotsu-borei-to, were compared to those of imipramine, a tricyclic antidepressant, in a mouse model of despair. Mice were placed in a water tank, from which there was no escape, for 15 min. The tank contained a water-wheel and the number of wheel rotations counted as escape attempts and, in accord with previous reports, imipramine (10 mg/kg i.p.), given either acutely or daily for 3 days 10 min before testing, markedly increased the number of wheel rotations. The Kampo medicines were administered for 14 consecutive days in the drinking water prior to testing. Hochu-ekki-to (60, 150 and 300 mg/kg/day) also increased wheel rotations but the effect was not dose-dependent. Yoku-kan-san markedly increased the number of wheel rotations at lower doses (60, 150 mg/kg/day), but decreased the number at the highest dose (300 mg/kg/day). Saiko-ka-ryukotsu-borei-to also increased the number of wheel rotations at the lowest dose (60 mg/kg/day), but decreased the number of rotations at higher doses (150, 300 mg/kg/day). These results suggest that these Kampo medicines, like imipramine, may ameliorate despair in mice.
