A kampo prescription, shimotsu-to, improves scopolamine-induced spatial cognitive deficits in rats

The effect of a Kampo (traditional Chinese medicine) prescription, Shimotsu-to, on spatial cognitive deficits produced by scopolamine was examined using an eight-arm radial maze and a T-maze. Scopolamine (SCOP; 0.075-0.3 mg/kg, ip) dose-dependently disrupted the radial maze performance. Single doses of Shimotsu-to (0.5 and 1.0 g/kg, po) as well as physostigmine (0.15 and 0.3 mg/kg, ip) improved the SCOP (0.3 mg/kg)-induced performance deficits in a dose-dependent manner. Shimotsu-to administered for 1 week in drinking water (0.5 and 1.0 g/kg/day) also exhibited dose-dependent reversal of SCOP-induced impairments in the radial maze performance. The same treatment improved SCOP (0.2 mg/kg)-induced impairments in T-maze delayed alternation performance. These data clearly demonstrated the beneficial effects of Shimotsu-to on spatial cognition.