Objective: To observe changes of contents of excitatory amino acids in focal cerebral ischemic tissue after electroacupuncture (EA) treatment at different time courses in cerebral ischemia and reperfusion(CI/R) rats so as to provide experimental evidence for selecting the best duration of EA stimulation in the treatment of apoplexy.Methods: Forty SD rats were randomized into control

model

EA-10 min

EA-30 min and EA-60 min groups.CI/R model was established by middle cerebral artery occlusion(MCAO) and reperfusion.EA(2 Hz

3.5 mA and continuous waves) was applied to "Baihui"(GV 20) and "Shuigou"(GV 26) for 10 min

30 min and 60 min respectively.Cerebral glutamate(Glu) and aspartic acid(Asp) concentrations were detected by using an amino acid automatic analyzer after homogenate and centrifugalization of the right brain tissue.Results: Compared with control group

Asp and Glu contents of model group and EA-10 min group increased significantly(P<0.01);while in comparison with model group

Asp level in EA-60 min group

and Glu level in EA-10 min

EA-30 min and EA-60 min groups decreased considerably(P<0.05).No significant differences were found between control and EA-30 min groups

and between control and EA-60 min groups in Asp and Glu levels(P>0.05).Conclusion: EA of GV20 and GV26 for 60 min can markedly reduce Glu and Asp levels in the topical cerebral infarct area in CI/R rats

which may contribute to its effect in relieving cerebral ischemic injury.Suitable duration of EA stimulation is definitely necessary for inducing a better therapeutic effect.