Voluntary access to a warm plate reduces hyperactivity in activity-based anorexia.

Activity-based anorexia (ABA) is considered an animal model of anorexia nervosa. In ABA, scheduled feeding in combination with voluntary wheel running leads to hyperactivity, reduced food intake, severe body weight loss and hypothermia. In this study it was investigated whether hyperactivity in ABA could be reduced by introducing a warm plate (which was voluntary accessible and did not influence ambient temperature) into a part of the cage. In ad libitum fed rats, the presence of the warm plate did not influence body temperature, running wheel activity (RWA), body weight or food intake. During ABA, however, rats preferred the warm plate and hypothermia was prevented, while hyperactivity and body weight loss were significantly reduced when compared to ABA rats without a plate. Correlation analysis revealed a significant association between basal body temperature and RWA during the light phase in ABA rats. However, there was no evidence that initiation of light phase RWA was a result of hypothermia. These data suggest that ABA rats prefer to prevent hypothermia passively by choosing a warm plate rather than actively regulating body temperature by hyperactivity.