Early maternal separation promotes alterations in the thermoregulatory profile of adult Wistar rats.

Stressful lifelong events may influence psychiatric diseases, like depression and anxiety. Interestingly, depressed patients have dysfunction of thermoregulatory cooling mechanisms. Thus, understanding the mechanisms related to the thermoregulatory changes in stress-related pathologies is important to better understand the symptoms and treatments for those diseases. However, the influence of early-life stress on the thermoregulatory profile of adults is unknown. In this study, we aimed to evaluate the thermoregulatory profile of adult male Wistar rats submitted to early-life stress by maternal separation (MS). On postnatal days 2-14, rats were submitted daily to MS for 3 h per day. At 3-4 months of age, anxiety-like behavior was evaluated using the open field test and elevated plus maze, depression-like behavior was evaluated using the forced swim test and thermoregulatory profile were also evaluated. In the behavioral tests, MS animals exhibited anxiety- and depression-like behaviors, and had higher core body temperatures during dark period of the circadian cycle, when compared to controls. In addition, MS animals presented higher hyperthermic and vasoconstriction responses than control animals when exposed to the warmth environment, and engaged in cold-seeking behavior whenever possible to select their preferred ambient temperature. The results suggest that, besides emotional alterations, MS induces a change in the thermoregulatory profile of rats that persists into adulthood.