Objective To observe the effect of electroacupuncture(EA)stimulation of"Baihui"(GV 20)-"Yintang"(EX-HN 3)on changes of learning-memory ability and hippocampal neuron structure in chronic stress-stimulation induced depression rats.Methods Forty-eight SD rats were randomly divided into normal

model

EA and medication(Fluoxetine)groups

with 12rats in each group.The depression model was established by chronic unpredictable mild stress stimulation(swimming in 4℃ water

fasting

water deprivation

reversed day and night

etc).Treatment was applied to"Baihui"(GV 20)and"Yintang"(EX-HN 3)for 20min

once every day for 21days.For rats of the medication group

Fluoxetine(3.3mg/kg)was given by gavage(p.o.)

once daily for 21days.The learning-memory ability was detected by Morris water maze tests.The pathological and ultrastructural changes of the hippocampal tissue and neurons were assessed by H.E.staining

light microscope and transmission electron microscopy

respectively.Results Compared to the normal group

the rats' body weight on day 14and day 21after modeling was significantly decreased in the model group(P<0.01)

the escape latency and total swimming distance in the 4 quadrants on day 10and 21were significantly increased in the model group(P<0.01).In comparison with the model group

the body weight on day 14and 21were significantly increased(P<0.05)

and the escape latency and total swimming distance levels were significantly decreased in the EA group(P<0.01)

suggesting an improvement of learning-memory ability.Observations of light microscope and transmission electron microscope showed that modeling induced pathological changes such as reduction in hippocampal cell layers

vague and broken cellular membrane

and ultrastructural changes of hippocampal neurons including swelling and reduction of mitochondria and mitochondrial crests were relived after EA and Fluoxetine treatment.Conclusion EA intervention can improve the learning-memory ability and relieving impairment of hippocampal neurons in depression rats

which may be one of its mechanisms underlying bettering depression.