EFFECT OF HACHIMI-JIO-GAN ON SCOPOLAMINE-INDUCED MEMORY IMPAIRMENT AND ON ACETYLCHOLINE CONTENT IN RAT-BRAIN

The effect of Hachimi-jio-gan (HJ) on scopolamine induced memory impai rment was studied using a radial maze performance, the effect of HJ on the central cholinergic system as measured by acetylcholine (ACh) con tent, choline acetyltransferase (CAT) and acetylcholinesterase (AChE) activities was also examined. HJ (0.01-1.0 g/kg, p.o.) showed no influ ence on the radial maze performance. However, with the administration of scopolamine (0.5 mg/kg, i.p.), the number of the correct choices de creased and the number of the error choices increased. HJ (0.1 and 0.5 g/kg, p.o.) reduced this scopolamine-induced cognitive disturbance. T he effect of HJ on ACh content and enzyme activities in the brain, fro ntal cortex, hippocampus and striatum was also investigated. In normal rats, HJ (0.1 and 0.5 g/kg, p.o. x 7 days) significantly increased AC h content in the frontal cortex, although it did not increased ACh con tent in the hippocampus. In scopolamine-treated rats, ACh content decr eased in the brain regions examined. HJ (0.5 g/kg, p.o.) inhibited a d ecrease in ACh content in the frontal cortex, and with the same dosage of HJ increased CAT activity in the frontal cortex and AChE activity in the hippocampus. These results suggest that the behavioral effects of HJ may be related to its effect on the central cholinergic system.