title: Central oxytocin and ANP receptors mediate osmotic inhibition of salt appetite in rats.
abstract: These studies evaluated the involvement of central oxytocin (OT) and atrial natriuretic peptide (ANP) receptors in the osmotic inhibition of hypovolemia-induced salt appetite. Rats were pretreated centrally with the A chain of the cytotoxin ricin conjugated to OT (rAOT) or ANP (rAANP) to selectively inactivate cells bearing these respective receptors, or rats were pretreated with the unconjugated A chain (rA) as a control. Hypovolemia was induced with subcutaneous colloid injections, and rats then were given either 2 M mannitol, which raises plasma osmolality but lowers plasma sodium, or 1 M NaCl, which raises both. Hypertonic mannitol inhibited saline ingestion in rA-treated control rats but stimulated ingestion in rAOT- and rAANP-treated rats, whereas hypertonic NaCl blunted saline ingestion in rA- and rAOT-treated rats but stimulated ingestion in rAANP-treated rats. Angiotensin II-induced saline intake was similarly potentiated in rAOT- and rAANP-treated rats, indicating that this treatment also activates central inhibitory OT and ANP pathways. These data suggest that central ANP receptors mediate both Na(+)- and osmolality-induced inhibition of NaCl ingestion, whereas central OT receptors primarily mediate osmolality-induced inhibition of NaCl ingestion in rats.
authors.affiliation: Department of Medicine, University of Pittsburgh, Pennsylvania 15261, USA.
authors.forename: R E
authors.initials: RE
authors.lastname: Blackburn
authors.forename: W K
authors.initials: WK
authors.lastname: Samson
authors.forename: R J
authors.initials: RJ
authors.lastname: Fulton
authors.forename: E M
authors.initials: EM
authors.lastname: Stricker
authors.forename: J G
authors.initials: JG
authors.lastname: Verbalis
mesh_terms: D000818:Animals; D001066:Appetite / Q000502:physiology*; D001810:Blood Volume / Q000502:physiology; D001921:Brain / Q000378:metabolism*; D004326:Drinking / Q000187:drug effects; D006982:Hypertonic Solutions / Q000494:pharmacology; D008297:Male; D008353:Mannitol / Q000494:pharmacology; D009994:Osmolar Concentration; D051381:Rats; D017207:Rats, Sprague-Dawley; D017461:Receptors, Atrial Natriuretic Factor / Q000502:physiology*; D018045:Receptors, Oxytocin / Q000378:metabolism*; D012965:Sodium Chloride
chemical_list: D006982:Hypertonic Solutions; D018045:Receptors, Oxytocin; D008353:Mannitol; D012965:Sodium Chloride; D017461:Receptors, Atrial Natriuretic Factor