Ginsenoside Rb1 regulates ChAT, NGF and trkA mRNA expression in the rat brain.

Ginsenoside Rb1 (Rb1), a saponin of North American ginseng (Panax quinquefolium L.), has been found to exert beneficial effects on memory and learning, putatively through its actions on the cholinergic system. In situ hybridization studies show that Rb1 increases the expression of choline acetyltransferase and trkA mRNAs in the basal forebrain and nerve growth factor mRNA in the hippocampus. Other neurotrophins (brain-derived neurotrophic factor, neurotrophin-3), genes encoding neuropeptides (preproenkephalin, preprotachykinin) and amyloid protein precursor were also studied, but no significant change was observed. These findings support the specificity of the effects of Rb1 on certain aspects of the cholinergic and neurotrophic systems.