Objective To observe the influence of electroacupuncture(EA)stimulation with different electrical current intensities and therapeutic intervals on learning-memory ability and expression ofβ-amyloid peptide Aβ1-40 and arginine vasopressin(AVP)genes in the hippocampal CA 1region in vascular dementia(VD)rats

so as to provide evidence for treatment of VD.Methods A total of 48 male SD rats were randomly divided into sham

model

0.5mA-5d-EA

1.5mA-5d-EA

0.5mA-1d-EA and 1.5 mA-1d-EA groups(n=8in each group).The VD model was established using modified 4-vessels occlusion method.EA(alternative 2Hz/15 Hz

0.5mA

1.5mA)was applied to"Baihui"(GV 20)and"Dazhui"(GV 14)for 30 min

once a day(1d)or once every 5dfor 10 times.The learning-memory ability was detected using Morris water maze tests(place navigation task and spatial probe trials)

and the expression of Aβ1-40 and AVP genes in hippocampal CA 1region was determined using real time-PCR.Results In comparison with the sham group

the average escape latency of place navigation task

and the duration for crossing the target-platform for the 1st time(spatial navigation task)were significantly increased(P<0.05)

and the times to cross the target-platform within 2min(spatial probe trials)were significantly decreased in the model group(P<0.05)

suggesting a reduction of learning-memory ability.The expression level of Aβ1-40 mRNA was remarkably increased(P<0.05)

and that of AVP mRNA notably decreased in the model group(P<0.05).Following EA intervention

the increased escape latency and the duration of crossing the target-platform for the 1st time and the increased Aβ1-40 mRNA expression

and the decreased target-platform crossing times within 2min as well the down-regulated AVP mRNA expression level were reversed in the 4EA groups compared with the model group(P<0.05).The therapeutic effects of higher stimulating intensity(1.5mA-1d-EA and1.5mA-5d-EA)were markedly superior to those of lower intensity(0.5mA-1d-EA and 0.5mA-5d-EA)

and the effects of higher frequency of EA intervention(0.5 mA-5d-EA and 1.5 mA-5d-EA)were obviously superior to those of lower frequency of EA(0.5mA-1d-EA and 1.5 mA-1d-EA)in suppressing the increased 3indexes and the decreased 2indexes mentioned above(P<0.05).Conclusion EA can improve the learning-memory ability of VD rats

which may be related to its effects in inhibiting the expression of Aβ1-40 mRNA and up-regulating the expression of AVP mRNA in hippocampal CA 1region;and the therapeutic effects of higher stimulating intensity and higher intervention frequency are obviously better than those of lower stimulating intensity and lower therapeutic frequency.