Abstract
Background: Rehmanniae radix preparata is a medicinal herb widely used in Asian countries, to replenish Yin and Vital Essence through strengthen the kidney function. In Oriental Medicine the brain has physiological relationship with the Vital Essence. And central nerve system (CNS) is also refered to as 'Sea of the Vital Essence'. So if the Vital Essence is strong it will nourish the brain and memory will all be keen. The purpose of this study was to investigate the effect of 7 to 14 days treatment with Rehmanniae radix preparata (3.4 g /100 g, per os) on retention performance of rats in a passive avoidance situation. Methods: Male Sprague-Dawley rats were trained on a one-trial passive avoidance task using a two-way shuttle box by giving a foot shock. They were tested for retention of 6h, 24h, 72h, 168h, and 336h after training. Results: Rehmanniae radix preparata treated rats showed a increased performance in retention test as compared to saline at 6hr (P<0.05) and 24hr (P<0.05). Conclusion: These data suggest that Rehmanniae radix preparata treatment can improve memory in the rat.