Effect of ginseng saponins on beta-amyloid-suppressed acetylcholine release from rat hippocampal slices.
In view of the facts that ginseng has been shown to improve age-related memory deficits and beta-amyloid-related peptides have been suggested to play a significant role in memory degeneration in the elderly, the present study was carried out to examine the effect of various ginsenosides on beta-amyloid peptides-modulated acetylcholine (ACh) release, a key neurotransmitter in memory processing, from the hippocampal slices. Addition of beta-amyloid fragment(25 - 35) (0.01 - 1 microM) in the superfusion medium suppressed the K(+)-evoked [(3)H]-ACh release from the rat hippocampal slices in a concentration-related manner and about 40 % reduction in ACh outflow was observed when incubating with the highest concentration of an amyloid fragment (1 microM). Inclusion of the ginsenoside components Rb(1) (0.1 microM), but not Rg(1), caused a rightward shift of the concentration-response curve of beta-amyloid. The reversal of the beta-amyloid-inhibited ACh release by Rb(1) was not blocked by tetrodotoxin (1 microM) indicating that an interaction occurs at the cholinergic synapse. These results suggest that Rb(1) may elicit its anti-amnesic effect by minimizing the inhibitory effect of beta-amyloid peptides.
Lee
T F
TF
Department of Biological Sciences, University of Alberta, Edmonton, Alberta T6G 2E9, Canada.
Shiao
Y J
YJ
Chen
C F
CF
Wang
L C
LC
D000109:Acetylcholine / Q000378:metabolism*; D016229:Amyloid beta-Peptides / Q000378:metabolism; D000818:Animals; D004305:Dose-Response Relationship, Drug; D036145:Ginsenosides; D006624:Hippocampus / Q000187:drug effects* / Q000378:metabolism; D066298:In Vitro Techniques; D008297:Male; D005894:Panax; D010446:Peptide Fragments / Q000378:metabolism; D010936:Plant Extracts / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012503:Saponins / Q000494:pharmacology*
D016229:Amyloid beta-Peptides; D036145:Ginsenosides; D010446:Peptide Fragments; D010936:Plant Extracts; D012503:Saponins; C078592:amyloid beta-protein (1-40); C075222:amyloid beta-protein (1-42); D000109:Acetylcholine