Objective The effects of ethanol (0.2 μmol/L) on the spontaneous electrical activity in the neurons of slice preparation of the nucleus accumbens septi (NAcc) was investigated. Methods Use extracellular recording.Results (1) In response to the application of ethanol into the superfusate for 10～15 min, spontaneous discharge rate (SDR) of 25 neurons was increased significantly, then, it was decreased (P<,0.01). This decreasing responses could be reversed by 0.2 μmol/L opiate antagonist naloxone (Nal), which suggests ethanol may exert some effects through interactions with endogenous opiate peptide systems of their receptors. (2) Following the application of DAGO, U-50 and D-PEN for 5～10 min respectively, the effect of ethanol might be reinforced. By statistical analysis of ANOVA, we conclude that the effect of DAGO, the selective μ opiate receptor agonist, is stronger than other two opiate receptor agonists. Conclusion (1) The spontaneous electrical activity of the NAcc neurons can be inhibited by ethanol. The effect of ethanol will be involved in endogenous opiate system. (2) It is possible that μ opiate receptor has the strongest effect on the ethanol inhibitory action.