title: Sodium sensing in the subfornical organ and body-fluid homeostasis.
abstract: The brain monitors conditions of body fluids and levels of circulating neuroactive factors to maintain the systemic homeostasis. Unlike most regions in the brain, circumventricular organs (CVOs) lack the blood-brain barrier, and serve as the sensing center. Among the CVOs, the subfornical organ (SFO) is the sensing site of Na+levels in body fluids to control water and salt intake. The SFO harbors neuronal cell bodies with a variety of hormone receptors and innervates many brain loci. In addition, the SFO harbors specialized glial cells (astrocytes and ependymal cells) expressing Nax, a Na+-level-sensitive sodium channel. These glial cells wrap a specific population of neurons with their processes, and control the firing activities of the neurons by gliotransmitters, such as lactate and epoxyeicosatrienoic acids (EETs), relevant to water/salt-intake behaviors. Recent advances in the understanding of physiological functions of the SFO are reviewed herein with a focus on the Na+-sensing mechanism by Nax.
authors: Division of Molecular Neurobiology, National Institute for Basic Biology, and School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Aichi 444-8787, Japan. Electronic address: hiyama@nibb.ac.jp.
authors: Takeshi Y
authors: TY
authors: Hiyama
authors: Division of Molecular Neurobiology, National Institute for Basic Biology, and School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Aichi 444-8787, Japan.
authors: Masaharu
authors: M
authors: Noda
mesh_terms: D000818:Animals; D001826:Body Fluids / Q000502:physiology*; D004326:Drinking / Q000502:physiology; D006706:Homeostasis; D006801:Humans; D006955:Hypernatremia / Q000503:physiopathology; D012964:Sodium / Q000502:physiology*; D015222:Sodium Channels / Q000502:physiology; D013356:Subfornical Organ / Q000502:physiology*
chemical_list: D015222:Sodium Channels; D012964:Sodium
keywords: Body-fluid homeostasis; Circumventricular organs; Hypernatremia; Na(x); Subfornical organ