NPY/AgRP neurons are not essential for feeding responses to glucoprivation

Peptides. 2007 Feb;28(2):214-25. doi: 10.1016/j.peptides.2006.08.036. Epub 2006 Dec 27.

Abstract

Animals respond to hypoglycemia by eating and by stimulating gluconeogenesis. These responses to glucose deprivation are initiated by glucose-sensing neurons in the brain, but the neural circuits that control feeding behavior are not well established. Neurons in the arcuate region of the hypothalamus that express neuropeptide Y (NPY) and agouti-related protein (AgRP) have been implicated in mediating the feeding response to glucoprivation. We devised a method to selectively ablate these neurons in neonatal mice and then tested adult mice for their feeding responses to fasting, mild hypoglycemia, 2-deoxy-d-glucose and a ghrelin receptor agonist. Whereas the feeding response to the ghrelin receptor agonist was completely abrogated, the feeding response to glucoprivation was normal. The feeding response after a fast was attenuated when standard chow was available but normal with more palatable solid or liquid diet. We conclude that NPY/AgRP neurons are not necessary for generating or mediating the orexigenic response to glucose deficiency, but they are essential for the feeding response to ghrelin and refeeding on standard chow after a fast.

MeSH terms

  • Agouti-Related Protein
  • Animals
  • Feeding Behavior*
  • Female
  • Hypoglycemia / metabolism*
  • Insulin / biosynthesis
  • Intercellular Signaling Peptides and Proteins / metabolism*
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Neurons / metabolism*
  • Neuropeptide Y / metabolism*
  • Receptors, G-Protein-Coupled / agonists
  • Receptors, Ghrelin

Substances

  • Agouti-Related Protein
  • Agrp protein, mouse
  • Insulin
  • Intercellular Signaling Peptides and Proteins
  • Neuropeptide Y
  • Receptors, G-Protein-Coupled
  • Receptors, Ghrelin