〔Abstract〕 Objective To study the pathway of noradrenalin(NA) effects on two type neurons(sleep-promoting neurons, interneurons) in the ventrolateral preoptic area(VLPO). Methods The whole cell patch clamp technique and pharmacological methods were used to analyze the pathway of NA excitating or inhibiting effects on the two type neurons in the VLPO. The types of NMDA receptor expressions in VLPO were identified by RT-PCR. Results Electrophysiological results showed that the excitatory effects of NA(100 μmol/L) on VLPO interneurons were blocked by NMDA receptor blocker(AP5)(P<0.05,n=8), but not by AMPA receptor(CNQX) and GABA receptor blocker. The inhibitory effects of NA(100 μmol/L) on the sleep-promoting neurons of VLPO were not blocked by AP5, CNQX or flumazenil. RT-PCR results showed that three subtypes of NMDA receptor(GluN2 A, GluN2 B, GluN1) were expressed in VLPO. Conclusion The excitatory effects of NA on VLPO interneurons is an indirect effects caused by glutamatergic neurons releasing glutamate, which is mediated by NMDA receptor of VLPO interneurons.