Influence of Isoflovone on Learning and Memory and Monoamine Neuro-transmitter in Ovariectomized Rats

Objective: To explore the effects and mechanisms of isoflovone(IS) on spatial learning,memory and monoamine neuro-transmitte,gonadotropin-releasing hormone(GnRH) inovariectomized rats.Method: The fifty Sprague-Dawley rats were ovariectomized.Ovariectomized rats were randomly divided into five groups,model group,estradiol benzoate(EB) group,IS low dose group,IS middle dose group,IS high dose group.EB group were treated with estradiol benzoate(0.2 mg·kg-1) by intraperitoneal injection once a week.IS groups were treated with IS(30,60,120 mg·g-1·d-1) by gavage one time daily.The spatial learning and memory performance were evaluated with Morris watermaze task.The contents of monoamine neuro-transmitter in hippocampus were measured,and GnRH in hypothalamus was measured.Result: ① As compared with control group,the latency period of model group increased significantly(P 0.05).Compared with model group,the latency period of EB group and IS middle dose group decreased significantly(P 0.05).②As compared with control group contents of norepinephrine(NE),dopamine(DA) and 5-hydroxytryptamine(5-HT) in hippocampus of model group decreased significantly(P 0.05).As compared with model group,contents of NE in hippocampus of IS high dose group increased significantly(P 0.05).As compared with model group,contents of DA and 5-HT in hippocampus of IS middle dose group,EB group increased significantly(P 0.05).③As compared with control group,contents of GnRH in hypothalamus of model group increased significantly(P 0.05).As compared with model group,contents of GnRH in hypothalamus of IS middle and high dose group,EB group decreased significantly(P 0.05).Conclusion: Isoflovone can improve the ovariectomized rats' impairment of spatial learning and memory by increasing contents of NE,DA,5-HT in hippocampus.Otherwise,isoflovone can decrease contents of GnRH in hypothalamus.