Maternal separation stress is a model of early life stress performed by the separation between dam and pups in the first days of life. The consequences of this early stress have been demonstrated on various behaviors, including feeding behavior. The results, however, are still controversial and it seems that a second exposure to stress later in life exacerbates the adverse outcomes. The present study aimed to determine the effects of maternal separation as a model of stress in early life, with or without a later life stress experience on eating behavior. Lactating Wistar rats were separated from their litters from postnatal day 2 (PND 2) to PND 14 for 3 h in the dark phase of the circadian cycle. The groups control (C) and separated (S) were composed. The assessment of food intake was performed between the ages of 60 and 150 days of life with a group that experienced only the early stress by maternal separation and with a second group that experienced the pre-weaning maternal separation stress and the food stress from 60 days of age. This food stress consisted of allowing visual and olfactory exposure of the animals to palatable food but did not allow the feeding. Maternal separation promoted higher palatable food and lower standard diet intake only after a double exposure to stress. Besides, the double exposure to stress promoted weight loss and an anxiety-like behavior. These outcomes were associated with a resistance to the anorectic effects of fluoxetine suggesting an alteration of the serotonergic system. Together, these findings indicate that maternal separation stress has long-lasting consequences on eating behavior, and that the dual exposure to stress seems more harmful to eating behavior outcomes. In addition, the results suggest that the serotonergic system is one candidate as the system mediating these alterations.
Keywords: Food stress; Maternal separation; Serotonergic system.
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