The subfornical organ in sodium appetite: Recent insights

To maintain sodium homeostasis, animals will readily seek and ingest salt when salt-depleted, even at concentrations that they typically find aversive when sodium replete. This innate behaviour is known as sodium (or salt) appetite. Salt appetite is subserved by a conserved brain network that senses sodium need and promotes the ingestion of salty substances when sodium-deficient. The subfornical organ (SFO) is a circumventricular organ that has diverse roles encompassing cardiovascular regulation, energy balance, immune responses, reproduction, and hydromineral balance. The SFO acts as a central sensor of sodium need and is essential for the generation of salt appetite. In this review, we discuss recent findings on the neurochemical and circuit-level organisation of the SFO in the context of sodium appetite. This article is part of the Special Issue entitled 'Hypothalamic Control of Homeostasis'.