Objective We have repeatedly demonstrated that electroacupuncture(EA)stimulation of"Shenmen"(HT7)-"Tongli"(HT 5)segment of the Heart Meridian can improve acute myocardial ischemia(AMI).This study aimed at observing the effect of EA on contents of hippocampal norepinephrine(NE)

and interleukin 6(IL-6)

IL-1β and tumor necrosis factor-α(TNF-α)in AMI rats

so as to explore its underlying mechanism.Methods SD rats were randomly divided into 3 groups:sham operation(sham)

model and EA(n=6 rats in each).The anterior descending branch(ADB)of the left coronary artery was occluded to make an AMI model.For rats of the sham group

a surgical suture was simply threaded beneath the ADB without ligation.EA(2 Hz/15 Hz

1 mA)was applied to bilateral"Shenmen"(HT 7)-"Tongli"(HT 5)and the middle-point between HT 7 and HT 5 for 30 min

once daily for 3 days.Electrocardiogram(ECG)of the neck-thoracic lead was recorded by using PowerLab 16.The contents of serum creatine kinase(CK)

hippocampal IL-6

IL-1β and TNF-αwere assayed by ELISA.The concentration of NE in hippocampal CA 1 area was detected by microdialysis combined with electrochemical detector.Results Compared with the sham group

the ECG-ST height

serum CK

hippocampal NE

IL-6

IL-1β and TNF-αcontents of the CA 1 region were significantly increased in the model group(P<0.001).Whereas

after EA intervention

the serum CK

hippocampal NE

IL-6

IL-1β and TNF-αcontents were obviously down-regulated relevant to the model group(P<0.05

P<0.001)

and the IL-6

IL-1β and TNF-αcontents were positively correlated with the NE level(P<0.001

P<0.01).Conclusion EA stimulation of the Heart Meridian may improve ischemic myocardial injury in AMI rats

probably by reducing the proinflammatory factors and hippocampal NE.