Effects of ginsenosides on maze performance and brain choline acetyltransferase activity in scopolamine-treated young rats and aged rats.

In young adult rats with scopolamine-induced cognitive impairment, choline acetyltransferase activity was increased in the medial septum, but not in the diagonal band, caudate and hippocampus, 30 min after the injection of ginsenosides Rg1 or Re. Rb1 and Rd had no effect on choline acetyltransferase activity. Aged rats showed a smaller number of initial correct responses in the radial-arm maze and a lower choline acetyltransferase activity in the medial septum, diagonal band, caudate and hippocampus than did young adult rats. Repeated i.p. injections of Rg1 increased the number of initial correct responses and the activity of choline acetyltransferase in the medial septum, but not in the diagonal band, caudate and hippocampus, in aged rats. These results suggest that Rg1 and Re may contribute the ameliorative effects through an increase of choline acetyltransferase activity in the medial septum.