title: Arcuate AgRP neurons and the regulation of energy balance.
abstract: The arcuate nucleus of the hypothalamus contains at least two populations of neurons that continuously monitor signals reflecting energy status and promote the appropriate behavioral and metabolic responses to changes in energy demand. Activation of neurons making pro-opiomelanocortin (POMC) decreases food intake and increases energy expenditure through activation of G protein-coupled melanocortin receptors via the release of α-melanocyte-stimulating hormone. Until recently, the prevailing idea was that the neighboring neurons [agouti-related protein (AgRP) neurons] co-expressing the orexigenic neuropeptides, AgRP, and neuropeptide Y increase feeding by opposing the anorexigenic actions of the POMC neurons. However, it has now been demonstrated that only AgRP neurons activation - not POMC neurons inhibition - is necessary and sufficient to promote feeding. Projections of AgRP-expressing axons innervate mesolimbic, midbrain, and pontine structures where they regulate feeding and feeding-independent functions such as reward or peripheral nutrient partitioning. AgRP neurons also make gamma aminobutyric acid , which is now thought to mediate many of critical functions of these neurons in a melanocortin-independent manner and on a timescale compatible with neuromodulation.
authors.affiliation: Unité de Biologie Fonctionnelle et Adaptative, CNRS-EAC 4413, Sorbonne Paris Cité, Université Paris Diderot-Paris 7 Paris, France.
authors.forename: Céline
authors.initials: C
authors.lastname: Cansell
authors.forename: Raphaël G P
authors.initials: RG
authors.lastname: Denis
authors.forename: Aurélie
authors.initials: A
authors.lastname: Joly-Amado
authors.forename: Julien
authors.initials: J
authors.lastname: Castel
authors.forename: Serge
authors.initials: S
authors.lastname: Luquet
keywords: GABA; agouti-related protein; dopamine; feeding behavior; metabolism; neuropeptide Y; obesity; reward