Ghrelin protects against stress by promoting the consumption of carbohydrates

T. Rodrigues, Z. Patterson, A. Abizaid

Location: Halls B-H
Presentation Time: Sunday, Nov 10, 2013, 11:00 AM – 12:00 PM
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Stress has shown to increase the rate of caloric intake leading to an eventual gain in weight. Ghrelin, a hormone that is produced in the stomach, is associated with increased caloric intake and weight gain. During acute as well as chronic stress exposure to psychogenic stressors, ghrelin is shown to be elevated. The eventual metabolic disturbances associated with these stressors leads to an imbalance in energy homeostasis and consequently increased adiposity. Interestingly, mice show a preference for carbohydrate rich diets when faced with chronic and acute stress. This change in diet preference might be important to alleviate stress-like symptoms. Here we hypothesize that ghrelin contributes to this change in preference. In our first study, we exposed mice with mutations to the ghrelin receptor (GHSR KO) to chronic social defeat stress for three weeks and compared their food intake, body weight and their preference to either a high fat snack or a sweet solution with those of stressed WT mice and non-stress control GHSR KO and WT mice. As expected, and in correlation with plasma ghrelin concentrations, stressed WT mice showed increases carbohydrate rich diets (increasing their total caloric intake) and body weight, but a decrease in the intake of a preferred diet rich in fat. These changes in behavior were only partially observed in stressed GHSR KO mice. Interestingly, we determined that, GHSR KO mice, showed more signs of stress induced depressive-like behaviors as determined by the forced swim test and measures of social interaction. Additionally when stressed mice are pair fed to non-stressed mice, we see the same depressive-like behaviors. This data suggests that the metabolic changes in food preference when under stress condition are important to protect against the psychopathological effects of stress, and that ghrelin plays an important role in mediating these effects.