The Effects Of Radix Polygalae On Learning And Memory And In Vivo Hippocampal Long-Term Potentiation And Brain Activity Of Acetylcholinesterase In AD Model Rats

Objective①To observe the effects of radix polygalae on learning and memory and the in vivo hippocampal long-term potentiation (LTP) and the activity of AchE (acetylcholinesterase).②To observe if these effects of radix polygalae are dose-dependent.Methods 32 healthy male Wistar rats were randomly divided into four groups:control group, model group, low dose radix polygalae group, high dose radix polygalae group. Basal forebrain injured rat was used as a model of Alzheimer's disease. Morris water maze tests were performed to observe the ability of learning and memory. Electrophysiological technique was used to observe the effects of radix polygalae on hippocampal CA1 region LTP. In vivo LTP was represented by the ratio of fEPSP amplitudes before and after high frequency stimulation (HFS). Chemical colorimetric assay was used to detect the activity of AchE according to the kit instructions.Results:1,The results of location navigation test:Through 5-day training all animals appeared learning-memory ability with the escape latency becoming shortter gradually The mean escape latency of model group was significantly longer than the control group (P<0.01), The mean escape latency of low dose radix polygalae group was significantly shorter than the model group (P<0.05),The mean escape latency of high dose radix polygalae group was significantly shorter than the model group (P< 0.01); The mean escape latency of low dose radix polygalae group was significantly longer than high dose radix polygalae group Polygala (P<0.01).2The results of space-exploration test:The times of passing platform of model rats significantly decreased than the control group (P<0.01); while the times of passing platform of low dose radix polygalae group significantly increased compared with model group(P<0.05), the times of passing platform of high dose radix polygalae group significantly increased too than those in model group (P<0.01); The times of passing platform of low dose radix polygalae group was significantly reduced than high dose radix polygalae group (P<0.01).3 The results of LTP:After the HFS 1 minute,30 minutes, and 60 minutes,the fEPSP amplitude of the control group respectively reached 198.1±6.6%,171.7±3.9%, and 160.6±3.7%, while the model group fEPSP amplitude was significantly lower than the control group(P<0.01), only respectively reached 132.1±2.0%,113.3±5.1%, and 109.1±2.9%;The fEPSP amplitude of high dose radix polygalae group respectively reached 181.8±4.9%,159.0±4.3%, and 151.5± 3.8%, which were higher (P<0.01) than the low dose radix polygalae group's 157.1±8.6%, 142.7±3.9%, and 131.2±3.9%;Compared with the model group both of high and low dose radix polygalae groups fEPSP amplitude were obviously improved (P<0.05).4 The results of AchE activity:The brain AchE activity of model group was significantly higher than the control group (P<0.01);The brain AchE activity of high dose radix polygalae group was significantly lower than the model group(P<0.01),while the brain AchE activity of low dose radix polygalae group was obviously lower than the model group too(P<0.05).Compared with low dose radix polygalae group the brain AchE activity of high dose radix polygalae group was significantly declined(P<0.01).Conclusion:Radix polygalae can significantly elevate the ability of learning and memory and the induction of LTP,and decrease the brain AchE activity And we believe the above effects show the dose-dependency.