PRECLINICAL STUDY: FULL ARTICLE: Ghrelin increases intake of rewarding food in rodents

TLDR

The study examined whether ghrelin signaling in the ventral tegmental area drives the reward and motivation for palatable food consumption. Disruption of ghrelin signaling in the VTA—via GHS‑R1A knockout, peripheral antagonist, or VTA lesions—suppressed rewarding food intake, eliminated reward‑evoked dopamine release, and reduced conditioned place preference, indicating that VTA ghrelin drives the incentive value of palatable food.

Abstract

ABSTRACT 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.