title: Coincident detection of CSF Na+ and osmotic pressure in osmoregulatory neurons of the supraoptic nucleus.
abstract: Behavioral and neuroendocrine responses underlying systemic osmoregulation are under the concerted control of centrally located osmoreceptors and cerebrospinal fluid (CSF) Na+ concentration ([Na+]) detectors. Although the process underlying osmoreception is understood, the mechanism by which [Na+] is detected and integrated with cellular information derived from osmoreceptors is unknown. Here, we show that shifts in extracellular [Na+] ([Na+]0) cause proportional changes in the relative Na+ permeability of mechanosensitive cation channels responsible for signal transduction in the osmosensory neurons of the supraoptic nucleus. This effect causes the generation of Na+ specific receptor potentials under isotonic conditions and modulates osmoreceptor potentials and electrical responsiveness during osmotic perturbation. These results provide a cellular basis for Na+-sensing and for the coordinated detection of CSF [Na+] and osmolality in central osmoregulatory neurons.
authors.affiliation: Centre for Research in Neuroscience, Montréal General Hospital and McGill University, Québec, Canada.
authors.forename: D L
authors.initials: DL
authors.lastname: Voisin
authors.forename: Y
authors.initials: Y
authors.lastname: Chakfe
authors.forename: C W
authors.initials: CW
authors.lastname: Bourque
mesh_terms: D000818:Animals; D002412:Cations / Q000378:metabolism; D005110:Extracellular Space / Q000378:metabolism; D007473:Ion Channels / Q000378:metabolism / Q000502:physiology; D008297:Male; D008465:Mechanoreceptors / Q000378:metabolism / Q000502:physiology; D009474:Neurons / Q000378:metabolism / Q000502:physiology*; D009994:Osmolar Concentration; D009997:Osmotic Pressure; D018408:Patch-Clamp Techniques; D010539:Permeability; D051381:Rats; D020318:Rats, Long-Evans; D015398:Signal Transduction / Q000502:physiology; D012964:Sodium / Q000134:cerebrospinal fluid*; D013495:Supraoptic Nucleus / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D014882:Water-Electrolyte Balance / Q000502:physiology*
chemical_list: D002412:Cations; D007473:Ion Channels; D012964:Sodium