J Ethnopharmacol. 1990 Mar; 28(3): 349-56.

Effects of shosaikoto, an oriental herbal medicinal mixture, on age-induced amnesia in rats.

Amagaya S, Umeda SH, Ogihara Y.

Department of Pharmacognosy, Faculty of Pharmaceutical Sciences, Nagoya City University, Japan.

The possibility of naturally occurring amnesia was examined in aging Fischer F254 rats. Animals 110 weeks old showed a loss of learning and memory in a passive avoidance responses (PAR) failure test. When 120 mg/kg/day of Shosaikoto extract was placed in the diet after 72 weeks of age to 110 weeks, it improved age-induced PAR failure in both the two-compartment avoidance box test and the step-down test. The responses of 110-week-old Shosaikoto-treated rats on both PAR failures were almost the same as those of non-treated 6-week-old rats. In these Shosaikoto-treated rats, dopamine was increased and norepinephrine and vanillyl mandelic acid were decreased in brain relative to those in non-treated aging rats.