Abstract
Effects of Kamikihi-To (KMK), a traditional Chinese medicine (Chinese name: Jia-Wei-Gui-Pi-Tang), on learning performance impairment caused by aging were evaluated in senescence accelerated mice (SAM). Normal diet containing 8% KMK extract was given to SAM-P/8, a senile-prone strain, and to SAM-R/1, a resistant strain, from 2 months old. Effects of KMK on learning performance were evaluated in 5 and 10 month old SAM using step through and step down type passive avoidance tests and shuttle box and lever press type conditioned avoidance tests. At 5 months old, KMK increased the retention rate in the step through test and decreased the number of errors in the step down test in SAM-P/8, though KMK had no effects in conditioned avoidance tests. KMK had no effects in any tests in SAM-R/1. At 10 months old, the decrease of the number of errors in the step down test and increase of the rate of the conditioned avoidance response in the shuttle box test were observed in SAM-P/8 treated with KMK. These results suggest that chronic administration of KMK can improve learning performance in the senescence model.
