American ginseng improves neurocognitive function in senescence-accelerated mice: Possible role of the upregulated insulin and choline acetyltransferase gene expression

Abstract

Aim: To investigate the effects of American ginseng on neurocognitive function and glucose regulation in senescence-accelerated mice. Methods: Male senescence-resistant inbred strains (SAMR1) and senescence-prone inbred strains (SAMP10) mice were divided into five groups and fed either a control diet or an American ginseng-supplemented diet (1% or 2% g/g) from 6weeks to 10months of age. Bodyweight, levels of fasting plasma glucose (FPG) and grading scores were monitored every month and neurocognitive functions were evaluated at 9months of age with a KUROBOX apparatus using a stress-free positive cue task. Gene expressions of peroxisome proliferator-activated receptor delta (PPAR-δ), insulin, choline acetyltransferase (ChAT) and amyloid precursor protein (APP) in the brain were measured by real-time quantitative reverse transcription polymerase chain reaction assays. Results: American ginseng decreased FPG in SAMR1 mice, but increased FPG in SAMP10 mice. Correct visit ratios were higher in both SAMR1 and SAMP10 strains consuming an American ginseng-supplemented diet. Gene upregulation of insulin and ChAT in the brain, but not of PPAR-δ or APP, was evident in American ginseng-fed groups. Conclusion: Daily consumption of American ginseng induced an enhancement in neurocognitive function in senescence-accelerated mice, which could be related to the upregulation of insulin and ChAT gene expression in the brain. © 2011 Japan Geriatrics Society.