In the present study, we investigated the effects of
Acori graminei rhizoma (AGR) on learning and memory for the Morris water maze task and on the central
cholinergic system of the rats with excitotoxic medial septum (MS) lesion. On the water maze test, the rats were trained to find a platform that was in a fixed position during 6 days and then they received a 60 s probe trial in which the platform was removed from the pool on the 7th day. Ibotenic lesioning of the MS impaired the performance on the maze test and it caused degeneration of
choline acetyltransferase and
acetylcholine esterase in the hippocampus, which are markers of the central
cholinergic system. Daily administrations of AGR (100 mg kg(-1), i.p.) for 21 consecutive days produced reversals of the
ibotenic acid-induced deficit in learning and memory. These treatments also reduced the loss of
cholinergic immunoreactivity in the hippocampus that was induced by
ibotenic acid. These results demonstrated that AGR ameliorated learning and
memory deficits through their effects on the central nervous system, and neuroprotection was partly evaluated through the effect of AGR on the
cholinergic system. Our studies suggest that AGR can possibly be used as treatment for
Alzheimer's disease.