Role of the 5-HT(1A) somatodendritic autoreceptor in the dorsal raphe nucleus on salt satiety signaling in rats

Exp Neurol. 2009 Jun;217(2):353-60. doi: 10.1016/j.expneurol.2009.03.015. Epub 2009 Mar 26.

Abstract

We investigated the possible role of 5-HT(1A) somatodendritic autoreceptors in the dorsal raphe nucleus (DRN) on salt intake response during basal conditions and following natriorexigenic challenge aroused by sodium depletion in rats. Acute systemic administration (76-1520 nmol/kg s.c.) of 8-OH-DPAT, a selective 5-HT(1A) somatodendritic autoreceptor agonist, induced a clear and dose-dependent preference for salt intake through free choice between water and 0.3 M NaCl simultaneously offered under basal conditions. Acute intra-DRN microinjection (7.5 nmol/rat) of 8-OH-DPAT significantly mimicked the acute systemic protocol in sodium-replete rats. Interestingly, microinjection of 8-OH-DPAT into the DRN raised an additional long-lasting increase of 0.3 M NaCl intake in sodium-depleted rats despite a high volume ingested 30 min after central injection. Conversely, chronic systemic treatment (1520 nmol/kg s.c.) with 8-OH-DPAT for 2 and 3 weeks or repeated intra-DRN microinjection (7.5 nmol/rat) evoked a significant long-term decrease in 0.3 M NaCl intake in sodium-depleted rats given only water and a sodium-deficient diet over the course of 24 h after furosemide injection. These results show a clear-cut involvement of the DRN 5-HT(1A) somatodendritic autoreceptors in sodium satiety signaling under basal conditions and during the consummatory phase of salt intake in sodium-depleted rats.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 8-Hydroxy-2-(di-n-propylamino)tetralin / pharmacology
  • Animals
  • Autoreceptors / drug effects
  • Autoreceptors / physiology*
  • Dendrites / drug effects
  • Dendrites / metabolism
  • Dendrites / ultrastructure
  • Dose-Response Relationship, Drug
  • Down-Regulation / drug effects
  • Drug Administration Schedule
  • Furosemide / pharmacology
  • Male
  • Microinjections
  • Pons / cytology
  • Pons / drug effects
  • Pons / metabolism
  • Raphe Nuclei / cytology
  • Raphe Nuclei / drug effects
  • Raphe Nuclei / metabolism*
  • Rats
  • Rats, Wistar
  • Receptor, Serotonin, 5-HT1A / metabolism*
  • Satiety Response / drug effects
  • Satiety Response / physiology*
  • Serotonin 5-HT1 Receptor Agonists
  • Serotonin Receptor Agonists / pharmacology
  • Sodium Chloride / metabolism
  • Sodium Chloride / pharmacology
  • Sodium Chloride, Dietary / metabolism*
  • Sodium Potassium Chloride Symporter Inhibitors / pharmacology
  • Water-Electrolyte Balance / drug effects
  • Water-Electrolyte Balance / physiology*

Substances

  • Autoreceptors
  • Serotonin 5-HT1 Receptor Agonists
  • Serotonin Receptor Agonists
  • Sodium Chloride, Dietary
  • Sodium Potassium Chloride Symporter Inhibitors
  • Receptor, Serotonin, 5-HT1A
  • Sodium Chloride
  • 8-Hydroxy-2-(di-n-propylamino)tetralin
  • Furosemide