Induction of Activity-Regulated Cytoskeleton-Associated Protein and c-Fos Expression in an Animal Model of Anorexia Nervosa.

Anorexia nervosa (AN) is a complex eating disorder characterized by reduced caloric intake to achieve body-weight loss. Furthermore, over-exercise is commonly reported. In recent years, animal models of AN have provided evidence for neuroplasticity changes in specific brain areas of the mesocorticolimbic circuit, which controls a multitude of functions including reward, emotion, motivation, and cognition. The activity-regulated cytoskeleton-associated protein (Arc) is an immediate early gene that modulates several forms of synaptic plasticity and has been linked to neuropsychiatric illness. Since the role of Arc in AN has never been investigated, in this study we evaluated whether the anorexic-like phenotype reproduced by the activity-based anorexia (ABA) model may impact its expression in selected brain regions that belong to the mesocorticolimbic circuit (i.e., prefrontal cortex, nucleus accumbens, and hippocampus). The marker of neuronal activation c-Fos was also assessed. We found that the expression of both markers increased in all the analyzed brain areas of ABA rats in comparison to the control groups. Moreover, a negative correlation between the density of Arc-positive cells and body-weight loss was found. Together, our findings suggest the importance of Arc and neuroplasticity changes within the brain circuits involved in dysfunctional behaviors associated with AN.