Serotonin 4 Receptors: A Cornerstone in Anorexia Nervosa?

Abstract

Adaptive decision-making to eat is crucial for survival but in anorexia nervosa, the brain persistently supports reduced food intake despite the physiological need to consume food. How the brain persists in reducing food intake sometimes even to the point of death despite the evolution of multiple mechanisms to ensure survival by governing adaptive eating behaviors remains mysterious. Food intake is a conserved behavioral trait between all species and involves numerous biological systems including the old phylogenetically serotonergic system. The present review focuses on anorexia and the implication of specific serotonin (5-HT, 5-hydroxytryptamine) receptors in food intake. In this context, we found that an early restrictive food intake due to stress, critically engages goaldirected (decision-making) systems upon the control of the serotonin 5-HT4 receptors, supporting that an early food restriction may first protect from depressive-like states but could become a deadly dependence. Finally, in the face to environmental challenges, an initial protective and beneficial adaptive response could become a pathologic dependence.