The subfornical organ (SFO) is an area in the brain characterized by lack of a blood-brain-barrier that contributes to interaction between the circulation and the central nervous system, and plays key roles in regulation of energy balance. The SFO has two subregions- the dorsolateral peripheral SFO (pSFO) and the ventromedial core of the SFO (cSFO). This study demonstrated the expression of voltage-gated Na+ channel 1.3 (Nav1.3) in the SFO neurons, and a higher Nav1.3 expression in the pSFO. Based on the Nav1.3 expression pattern, intrinsic electrophysiological properties were compared between cSFO and non-cSFO neurons (putative pSFO neurons) identified by a SmartFlare mRNA probe. The patch clamp results revealed a bursting firing pattern in cSFO neurons and a higher spontaneous neuronal activity in non-cSFO neurons. The higher neuronal activity might be related to a more depolarized resting membrane potential and a higher trend of Na+ current density.