Effects of Hochu-ekki-to, Yoku-kan-san and Saiko-ka-ryukotsu-borei-to on behavioral despair and acetic acid-induced writhing in mice.

Effects of the Kampo (Chinese herbal) medicines Hochu-ekki-to Yoku-kan-san and Saiko-ka-ryukotsu-borei-to, on behavioral despair and acetic acid-induced writhing were studied in mice. The Kampo medicines were administered for 14 consecutive days in the drinking water. In a behavioral despair study, mice were placed in a water tank containing a water wheel from which there was no escape for 15 min and the number of wheel rotations was counted as escape attempts. In accord with previous studies, imipramine (10 mg/kg i.p.) given daily for 3 days 10 min before testing markedly increased the number of wheel rotations. Hochu-ekki-to (60, 150 and 300 mg/kg/day) similarly increased the number of wheel rotations but the effect was not dose-dependent. Yoku-kan-san markedly increased the number of wheel rotations at lower doses (60 and 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 does (60 mg/kg/day) but decreased the number at higher doses (150 and 300 mg/kg/day). In an antinociception study, all these Kampo medicines reduced the number of acetic acid-induced writhings, although the effect of Saiko-ka-ryukotsu-borei-to were not dose-dependent. These results suggests that these Kampo medicines may have antidepressive and antinociceptive properties.