Central oxytocin and ANP receptors mediate osmotic inhibition of salt appetite in rats

Am J Physiol. 1995 Aug;269(2 Pt 2):R245-51. doi: 10.1152/ajpregu.1995.269.2.R245.

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.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Appetite / physiology*
  • Blood Volume / physiology
  • Brain / metabolism*
  • Drinking / drug effects
  • Hypertonic Solutions / pharmacology
  • Male
  • Mannitol / pharmacology
  • Osmolar Concentration
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, Atrial Natriuretic Factor / physiology*
  • Receptors, Oxytocin / metabolism*
  • Sodium Chloride*

Substances

  • Hypertonic Solutions
  • Receptors, Oxytocin
  • Mannitol
  • Sodium Chloride
  • Receptors, Atrial Natriuretic Factor