Activity-based anorexia activates CRF immunoreactive neurons in female rats

•Activity-based anorexia (ABA) is an established animal model for anorexia nervosa.•In PVN, DMH and EW, ABA activates more CRF immunoreactive cells compared to AL and AC.•In the DMH, ABA increases the number of CRF immunoreactive cells.•CRF might play a role in the development and maintenance of ABA. Activity-based anorexia (ABA) is a well-established animal model mimicking the eating disorder anorexia nervosa (AN). Since the pathophysiology of AN is yet poorly understood and specific drug treatments are lacking so far, animal models might be useful to further understand this disease. ABA consists of time-restricted access to food for 1.5 h/day and the possibility to exercise in a running wheel for 24 h/day. This combination leads to robust body weight loss as observed in AN. Here, we investigated the activation of brain corticotropin-releasing factor (CRF) neurons, a transmitter involved in the response to stress, emotional processes and also food intake. After development of ABA, rat brains were processed for c-Fos and CRF double immunohistochemistry. ABA increased the number of c-Fos/CRF double labeled neurons in the paraventricular nucleus (PVN) and the dorsomedial hypothalamic nucleus (DMH) compared to the ad libitum (AL, ad libitum fed, no running wheel) and activity (AC, ad libitum fed, running wheel, p 0.05) group. Also the number of CRF neurons was increased in the DMH of ABA rats compared to AL and AC (p