[A role for orexins and melanin-concentrating hormone in the central regulation of feeding behavior]

The hypothalamus is the most important region in the control of food intake and body weight. The ventromedial 'satiety center' and lateral hypothalamic 'feeding center' have been implicated in the regulation of feeding and energy homeostasis by various studies of brain lesions. Orexins(orexin A and orexin B) and melanin-concentrating hormone (MCH), whose intracerebroventricular injections increase food intake, are localized in the lateral hypothalamus and provide diffuse projections throughout the brain. Orexins and MCH neurons have a coextensive distribution, but are not colocalized. Orexins and MCH may affect feeding behavior through distinct neuronal pathways. We here describe the effect of orexins and MCH on feeding behavior from the physiological, neuroanatomical and molecular studies.