Abstract:Objective: To investigated the influence YN-3 on the chronic stress depression rats‘ learning-memory behaviors and research of it‘s mechanism.Method: Forty SD rats were divided into control,model,YN-3 and Prozac groups.Chronic stress model was established by breeding separately and unpredictable chronic mixed stimulation for 21 days.Observe the changes of Open-field test which shows the ability of spontaneous movement and "Y"-maze test which shows the learning-memory behavior ability.The expression of CREB(cAMP response-element binding protein) in hippocampal tissue was detected by immunohistochemical technology.Result: The results of spontaneous movements and learning-memory behaviors of the model group was declined significantly compared with control group(P<0.01),and which of the YN-3 group was improved compared with model group(P<0.05);the expression of CREB in hippocampal of the model rats was declined significantly compared with control group(P<0.01) and which was increased in the YN-3 group compared with modelgroup(P<0.01),but there was no significantly difference between the YN-3 group and Prozac group.Conclusion: The results show that as an early interference instrumentality,Chinese herb formula YN-3 could antagonize the change of learning-memory behavior which was caused by chronic stress,the possible mechanism of it might related to the changes of signal substances such as CREB in the hippocampi tissue.