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Objective The present study was carried out to investigate the effect of electroacupuncture (EA) on paraventricular nucleus (PVN) neurons in surgical trauma stressed rats, and further study the central mechanism underlying the electroacupuncture.Methods Animals were randomly divided into non-stressed group (Control), surgical trauma stressed group (Trauma), Neiguan EA applied on surgical trauma stressed group (Trauma+EA PC 6).The intracellular recording techniques in PVN neurons of rat hypothalamic slices were used to observe the difference of electrophysiological characteristics of PVN neurons among Control, Trauma, and Trauma+EA PC 6 groups.Results The intensity rheobase of intracellular current injection to initiate action potential in Trauma group decreased significantly (P<0.01) and membrane resistance increased significantly (P<0.01), compared with that in Control group.Significant change could not be observed in the other parameters in Trauma group compared to Control group.In Trauma+EA PC 6 group, the rheobase increased, while membrane resistance and Max L.slope (P<0.05) decreased significantly, compared with that in Trauma group.The excitatory postsynaptic potentials (EPSPs) or inhibitory postsynaptic potentials (IPSPs) in PVN neurons could be elicited by focal electrical stimulation near the fornix.The EPSPs and IPSPs were elicited in 69%, and 6% of tested PVN neurons in Control group (n=16), respectively.However, in Trauma group, the EPSPs were elicited only in 10% of 10 tested PVN neurons by focal electrical stimulation near the fornix, indicating a significant decrease in induction rate of the postsynaptic potentials (P<0.01).In Trauma+EA PC 6 group, focal electrical stimulation near the fornix evoked EPSPs in 50% of 8 PVN neurons, showing an increase of induction rate of the postsynaptic potentials.Conclusion These results indicate that the neurons of the PVN may be involved in regulation of cardiac function when Neiguan EA was applied on surgical trauma rats.