RESUMO
AIM: To investigate the effects of Dihuang Yizhi Extract(DHYZE) on learning-memory ability and the central cholinergic system of the rats with Alzheimer's disease(AD) and to explore the possible mechanism of action. METHODS: Aggregated A?25-35 was injected into the right hippocampus of the rats to make experimental rat model of AD.The behavioral abnormalities were investigated by shuttle box.The contents of acetylcholine(Ach)、cholinesterase(ChE) activity、cyclic AMP response element-binding protein(CREB) and phosphorylated CREB serine 133(pCREB Ser133) in hippocampus were measured. RESULTS: DHYZE could markedly improve the function of learning and memory of rats in AD model in a dose-dependent manner.The contents of Ach and AchE activity in hippocampaus increased obviously in DHYZE medium dose group and high dose group compared with AD group.Such promotion was dose-dependent.The contents of pCREB Ser133 in hippocampaus increased obviously in DHYZE high dose group compared with AD group. CONCLUSION: The results indicate DHYZE could improve the ability of spatial learning and memory in AD rats.The mechanism might be associated with improving the impairment of the central cholinergic neurons induced by A?25-35 and activating CREB signal pathway in hippocampus of AD rats.