Effects Of Schisandra On The Learening And Memory And The LTP Induced At PP-DG Synapses In Hippocanpus Of Ovariectomized Rodent

The aged-related dementia which also named Alzheimer's disease(AD)becomesmore and more common original cause to the human health. According to theepidemiology survey the postmenopausal women had more than 1.5 to 3 times on riskof AD compared with the same age men. So, it has an important clinic meaning tostudy on the precaution and put forward the effective strategy on the AD. Theestrogen replacement therapy was a most studied and more disputed therapeuticswhich could improve some symptoms like the memory deficit of AD to thepostmenopausal women markedly. However, the ERT maybe bring some unforeseenside effect to the patient, which is the main cause to restrict the use of ERT on theclinic. So, searching for some natural effective component which have estrogen-likeaction to replace the estrogen on the AD therapy has become a research highlight. Asa kind of Bushen's Chinese medicine, the effect of Fructus Schisandra chinensis onthe brain function was received extensive attention, but how the Fructus Schisandrachinensis improve the memory and whether its effect is contribute to estrogen-likeaction or not is also unclear.So we first use the mice by removed twin ovary to establish the cognitive deficitmodel with the low concentration of estrogen; Then, the step-through test andNADPH-d histochemieal staining were used to evaluate the memory and observe thenumber of NOS positive neurons in the hippocampus; the extracellularelectrophysicological recordings were used to observe the synaptic plasticity. Themain results were as follows:1.The memory of ovariectomized mice was impaired significantly and thenumber of NOS positive neurons was decreased in the subregions of hippocampuscompared to that of control group; Fructus Schisandra chinensis ethanol extractsenhanced the memory of ovariectomized mice and increase the number of NOSpositive neurons in hippocampus significantly; But the Fructus Schisandra chinensispetroleum ether extracts significantly decreased the maintenance of memory ofovariectomized mice and further decreased the number of NOS positive neurons in hippocampus.2. The LTP induced on ovariectomized rat was depressed significantly whencomparied to the control group, representing the PS and the lasting time of LTPdecreased significantly. The Fructus Schisandra chinensis ethanol extracts or estrogencould improve the synaptic plasticity, increased the amplitude of PS and lasting timeof the LTP induced by high frequency stimulation in ovariectomized rat.These results indicated that the memory improvement of Fructus Schisandrachinensis was contributed to the estrogen-like action and the effective componentswas concentrated in their ethanol extracts. And suggested that Fructus Schisandrachinensis ethanol extracts might has the estrogen-like action and its effect on thememory improvement might be related to the distribution and synthesis of the NOSpositive neurons and the synaptic plasticity in hippocampus.