Objective To observe the effect of electroacupuncture(EA) preconditioning of “Shenmen”(HT7)-“Tongli”(HT5) segment of the Heart Meridian on neuronal electrical activities of lateral hypothalamus area(LHA) in rats with myocardial ischemia reperfusion injury(MIRI)

so as to investigate its possible mechanism underlying improvement of MIRI. Methods Twenty-four SD rats were randomly divided into sham

model

EA and damage + EA(D+EA) groups

with 6 rats in each group. The MIRI model was established by occlusion of the anterior descending branch(ADB) of the left coronary artery for 30 min

followed by reperfusion for 2 h. In the sham operation group

the ADB was only threaded beneath the artery without ligation. EA(2 Hz

1 V) was applied to bilateral HT7-HT5 for 20 min

once daily for 7 days. In the D+EA group

FN was injected with 0.4 μL of 1 g/L kainic acid solution. Electrocardiogram(ECG) of the neck-thoracic lead was recorded by using PowerLab. The electrical activities of the LHA region were recorded by the implanted microelectrode array(2×4) and Plexon multi-channel acquisition system. Cluster analysis of neuronal signals was carried out by Offline Sorter software. The discharge waveforms

autocorrelation and cross-correlation of neuronal activities were analyzed by using Neuro Explorer software. Results Compared with the sham group

the ECG-ST height was significantly increased(P<0.05)

the discharge frequency of pyramidal neurons was significantly reduced(P<0.01)

while the discharge frequency of interneurons was increased(P<0.01) in the model group. After EA treatment

the ECG-ST height was significantly decreased(P<0.05)

the discharge frequency of pyramidal neurons was significantly increased(P<0.01) relevant to the model group. In comparison with the EA group

the ECG-ST height in the D+EA group was significantly elevated(P<0.05)

whereas the discharge frequency of pyramidal neurons was significantly decreased(P<0.01). The discharge frequency of interneurons was kept increasing after MIRI. Real-time spectrum analysis showed that the local field potential spectrum energy of the EA group was significantly lower than that of the model group and the D+EA group. Conclusion EA preconditioning of Heart Meridian can significantly increase the discharge frequency of LHA excitatory pyramidal neurons and reduce the energy of the local field potential spectrum

which maybe one of the important mechanisms of EA in anti-MIRI.