Glucagon-Like Peptide-1 Receptor Signaling in the Lateral Dorsal Tegmental Nucleus Regulates Energy Balance

Neuropsychopharmacology. 2018 Feb;43(3):627-637. doi: 10.1038/npp.2017.225. Epub 2017 Sep 18.

Abstract

The neurobiological substrates that mediate the anorectic effects of both endogenous glucagon-like peptide-1 (GLP-1) and exogenous GLP-1 receptor (GLP-1R) agonists are an active area of investigation. As the lateral dorsal tegmental nucleus (LDTg) expresses the GLP-1R and represents a potential neuroanatomical hub connecting the nucleus tractus solitarius (NTS), the major central source of GLP-1, with the other nuclei in the midbrain and forebrain, we tested the hypothesis that GLP-1R signaling in the LDTg controls food intake. Direct activation of LDTg GLP-1R suppresses food intake through a reduction in average meal size and independent of nausea/malaise. Immunohistochemical data show that GLP-1-producing neurons in the NTS project to the LDTg, providing anatomical evidence of endogenous central GLP-1 in the LDTg. Pharmacological blockade of LDTg GLP-1Rs with exendin-(9-39) dose-dependently increases food intake and attenuates the hypophagic effects of gastric distension. As GLP-1 mimetics are administered systemically in humans, we evaluated whether peripherally administered GLP-1R agonists access the LDTg to affect feeding. Immunohistochemical data show that a systemically administered fluorescent GLP-1R agonist accesses the LDTg and is juxtaposed with neurons. Additionally, blockade of LDTg GLP-1Rs attenuates the hypophagic effects of a systemic GLP-1R agonist. Together, these data indicate that LDTg GLP-1R signaling controls energy balance and underscores the role of the LDTg in integrating energy balance-relevant signals to modulate feeding.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Central Nervous System Agents / pharmacology
  • Dose-Response Relationship, Drug
  • Eating / drug effects
  • Eating / physiology*
  • Exenatide
  • Glucagon-Like Peptide 1 / metabolism
  • Glucagon-Like Peptide-1 Receptor / agonists
  • Glucagon-Like Peptide-1 Receptor / antagonists & inhibitors
  • Glucagon-Like Peptide-1 Receptor / metabolism*
  • Male
  • Neural Pathways / cytology
  • Neural Pathways / drug effects
  • Neural Pathways / metabolism
  • Neurons / cytology
  • Neurons / drug effects
  • Neurons / metabolism
  • Peptide Fragments / pharmacology
  • Peptides / pharmacology
  • Rats, Sprague-Dawley
  • Solitary Nucleus / cytology
  • Solitary Nucleus / drug effects
  • Solitary Nucleus / metabolism
  • Tegmentum Mesencephali / cytology
  • Tegmentum Mesencephali / drug effects
  • Tegmentum Mesencephali / metabolism*
  • Venoms / pharmacology

Substances

  • Central Nervous System Agents
  • Glucagon-Like Peptide-1 Receptor
  • Peptide Fragments
  • Peptides
  • Venoms
  • exendin (9-39)
  • Glucagon-Like Peptide 1
  • Exenatide