Comparison of central administration of corticotropin-releasing hormone and urocortin on food intake, conditioned taste aversion, and c-Fos expression

Peptides. 2000 Mar;21(3):345-51. doi: 10.1016/s0196-9781(00)00153-4.

Abstract

Corticotropin-releasing hormone (CRH) is a potent regulator of the hypothalamic-pituitary-adrenal axis, and reduces food intake when administered into the third cerebral ventricle (i3vt). However, CRH also promotes conditioned taste aversion (CTA) learning which indicates that its anorectic effects are accompanied by aversive consequences that would reduce food intake independently of energy regulation. Urocortin (Ucn) is a closely related mammalian peptide that binds to both identified CRH receptor subtypes and also reduces food intake when administered i3vt. The present experiments compared the aversive consequences of i3vt administration of CRH and Ucn at doses that produced comparable decrements in food intake. Experiment 1 found that 1.0 microg Ucn and 2.0 microg CRH produced similar reductions in food intake. Experiment 2 demonstrated that, at these doses, CRH but not Ucn promoted robust and reliable CTA learning. A third experiment showed comparable increased c-Fos-like immunoreactivity after Ucn and CRH in forebrain and hindbrain structures associated with food intake. It is concluded that Ucn, at doses that reduce food intake to levels like that observed after administration of CRH, do not produce similarly aversive consequences.

Publication types

  • Comparative Study
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amygdala / drug effects
  • Amygdala / metabolism
  • Animals
  • Avoidance Learning / drug effects*
  • Cerebral Ventricles / drug effects
  • Cerebral Ventricles / physiology*
  • Corticotropin-Releasing Hormone / administration & dosage
  • Corticotropin-Releasing Hormone / pharmacology*
  • Energy Intake / drug effects*
  • Feeding Behavior / drug effects
  • Gene Expression Regulation / drug effects
  • Genes, fos*
  • Injections, Intraventricular
  • Male
  • Rats
  • Rats, Long-Evans
  • Reaction Time
  • Saccharin
  • Solitary Nucleus / drug effects
  • Solitary Nucleus / metabolism
  • Taste*
  • Urocortins

Substances

  • Urocortins
  • Corticotropin-Releasing Hormone
  • Saccharin