Model of ghrelin’s roles in stress-induced behaviors.
(i) CSDS in mice, which is a model of prolonged psychosocial stress in humans, results in several persisting behavioral deficits reminiscent of depression. (ii) Psychosocial stress also leads to elevations in circulating levels of ghrelin, which, in turn (iii), interacts with GHSRs localized to catecholaminergic neurons in the brain (the exact expression site[s] of these GHSR-containing, catecholaminergic neurons — most of which are dopaminergic — has not been identified but likely include the VTA). (iv) Engagement of these neurons by ghrelin induces a series of changes that minimizes what would otherwise be worsened depression-like behaviors, while at the same time, (v) induces HFD food-reward behavior and hyperphagia, leading to (vi) increased intake of highly palatable, calorically dense comfort foods and increased body weight.
Copyright © 2014 American Society for Clinical Investigation