title: Centrally Administered Ghrelin Acutely Influences Food Choice in Rodents.
abstract: We sought to determine whether the orexigenic hormone, ghrelin, is involved in the intrinsic regulation of food choice in rats. Ghrelin would seem suited to serve such a role given that it signals hunger information from the stomach to brain areas important for feeding control, including the hypothalamus and reward system (e.g. ventral tegmental area, VTA). Thus, in rats offered a choice of palatable foods (sucrose pellets and lard) superimposed on regular chow for 2 weeks, we explored whether acute central delivery of ghrelin (intracerebroventricular (ICV) or intra-VTA) is able to redirect their dietary choice. The major unexpected finding is that, in rats with high baseline lard intake, acute ICV ghrelin injection increased their chow intake over 3-fold, relative to vehicle-injected controls, measured at both 3 hr and 6 hr after injection. Similar effects were observed when ghrelin was delivered to the VTA, thereby identifying the VTA as a likely contributing neurobiological substrate for these effects. We also explored food choice after an overnight fast, when endogenous ghrelin levels are elevated, and found similar effects of dietary choice to those described for ghrelin. These effects of fasting on food choice were suppressed in models of suppressed ghrelin signaling (i.e. peripheral injection of a ghrelin receptor antagonist to rats and ghrelin receptor (GHSR) knock-out mice), implicating a role for endogenous ghrelin in the changes in food choice that occur after an overnight fast. Thus, in line with its role as a gut-brain hunger hormone, ghrelin appears to be able to acutely alter food choice, with notable effects to promote "healthy" chow intake, and identify the VTA as a likely contributing neurobiological substrate for these effects.
authors.affiliation: Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden.
authors.forename: Erik
authors.initials: E
authors.lastname: Schéle
authors.affiliation: Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden.
authors.forename: Tina
authors.initials: T
authors.lastname: Bake
authors.affiliation: Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden.
authors.forename: Cristina
authors.initials: C
authors.lastname: Rabasa
authors.affiliation: Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden.
authors.forename: Suzanne L
authors.initials: SL
authors.lastname: Dickson
mesh_terms: D000821:Animal Feed; D000818:Animals; D005215:Fasting; D005518:Food Preferences / Q000187:drug effects*; D054439:Ghrelin / Q000008:administration & dosage*; D007267:Injections; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D051381:Rats; D054440:Receptors, Ghrelin / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D017557:Ventral Tegmental Area / Q000187:drug effects / Q000502:physiology
chemical_list: D054439:Ghrelin; D054440:Receptors, Ghrelin