Ghrelin increases intake of rewarding food in rodents.
We investigated whether ghrelin action at the level of the ventral tegmental area (VTA), a key node in the mesolimbic reward system, is important for the rewarding and motivational aspects of the consumption of rewarding/palatable food. Mice with a disrupted gene encoding the ghrelin receptor (GHS-R1A) and rats treated peripherally with a GHS-R1A antagonist both show suppressed intake of rewarding food in a free choice (chow/rewarding food) paradigm. Moreover, accumbal dopamine release induced by rewarding food was absent in GHS-R1A knockout mice. Acute bilateral intra-VTA administration of ghrelin increased 1-hour consumption of rewarding food but not standard chow. In comparison with sham rats, VTA-lesioned rats had normal intracerebroventricular ghrelin-induced chow intake, although both intake of and time spent exploring rewarding food was decreased. Finally, the ability of rewarding food to condition a place preference was suppressed by the GHS-R1A antagonist in rats. Our data support the hypothesis that central ghrelin signaling at the level of the VTA is important for the incentive value of rewarding food.
Egecioglu
Emil
E
Department of Physiology/Endocrinology, The Sahlgrenska Academy at the University of Gothenburg, SE-405 30 Gothenburg, Sweden. emil.egecioglu@medic.gu.se
Jerlhag
Elisabet
E
Salomé
Nicolas
N
Skibicka
Karolina P
KP
Haage
David
D
Bohlooly-Y
Mohammad
M
Andersson
Daniel
D
Bjursell
Mikael
M
Perrissoud
Daniel
D
Engel
Jörgen A
JA
Dickson
Suzanne L
SL
D000818:Animals; D003214:Conditioning, Classical / Q000187:drug effects; D004298:Dopamine / Q000378:metabolism; D004435:Eating / Q000187:drug effects*; D054439:Ghrelin / Q000494:pharmacology*; D007267:Injections; D008032:Limbic System / Q000187:drug effects*; D008297:Male; D008636:Mesencephalon / Q000187:drug effects*; D051379:Mice; D018345:Mice, Knockout; D009434:Neural Pathways / Q000187:drug effects*; D009714:Nucleus Accumbens / Q000187:drug effects; D054440:Receptors, Ghrelin / Q000187:drug effects / Q000235:genetics; D012201:Reward; D015398:Signal Transduction / Q000187:drug effects; D013649:Taste / Q000187:drug effects; D017557:Ventral Tegmental Area / Q000187:drug effects*
D054439:Ghrelin; D054440:Receptors, Ghrelin; D004298:Dopamine