Eating behavior in anorexia nervosa--an excess of both orexigenic and anorexigenic signalling?
Anorexia nervosa (AN) is a disorder characterized by abnormal eating behavior, weight regulation, and disturbances in attitudes and perceptions toward body weight and shape. Although progress has been made in the treatment of AN, a substantial portion of patients have a limited response to treatment. Multiple endocrine and metabolic changes occur after prolonged starvation, conserving energy and protein. A number of the endocrine findings in patients with AN may be secondary to adaptive mechanisms. However, AN differs from simple starvation in that excess of both feeding-stimulatory (orexigenic) and feeding-inhibitory (anorexigenic) signalling is characteristic, producing the "mixed" signal about satiety and desire to feed. This leads to a failure of the adaptive feeding response that is initiated by a decrease in leptin, an adiposity signal from fat tissue, and the resultant increase and decrease of orexigenic and anorexigenic signalling, respectively. The hypothesis of unbalanced shift of feeding-regulatory circuitry places anorexigenic corticotropin-releasing factor and orexigenic neuropeptide Y in the final common neurobiological substrate for AN. Therapeutic intervention using such receptor antagonists may lead to more successful and targeted psychopharmacological treatment.
Inui
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Second Department of Internal Medicine, Kobe University School of Medicine, Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan. inui@med.kobe-u.ac.jp
D000856:Anorexia Nervosa / Q000503:physiopathology*; D001923:Brain Chemistry / Q000502:physiology; D002352:Carrier Proteins / Q000502:physiology*; D005247:Feeding Behavior / Q000502:physiology*; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D009479:Neuropeptides / Q000502:physiology*; D000068797:Orexins; D015398:Signal Transduction / Q000502:physiology*
D002352:Carrier Proteins; D047908:Intracellular Signaling Peptides and Proteins; D009479:Neuropeptides; D000068797:Orexins