The role of leptin in regulation of neuronal activity associated with control of food intake

Abstract

The process of eating is a set of complex and different forms of behavior. Its regulation is based up on appetite control and one of the important factors in that system is leptin, a peptide hormone primarily synthesized in the adipose tissue. Leptin levels, besides the amount of fat tissue in the body, depend on: food intake, sex, age, physical activity and glucose up-take. In addition, leptin secretion displays circadian rhythm. The effects of this hormone are mediated via leptin receptors, which are distributed in the central nervous system and several other tissues. Activation of the receptors initiates a cascade of several signaling pathways, of which JAK2/STAT3 is the most important pathway in the process of feeding regulation and energy homeostasis. Leptin controls energy balance and body weight by activating leptin receptors in the hypothalamus, and the arcuate nucleus of the hypothalamus is the main site of its action. Within that nucleus, leptin stimulates the activity of anorexigenic POMC/CART neurons and inhibits the activity of orexigenic AgRP/NPY neurons. In addition, leptin regulates the expression of (an)orexigenic neuropeptides in the ventromedial, paraventricular nucleus and in the lateral hypothalamus. Bearing these facts in mind, studies that were conducted have shown that leptin may have its place in the treatment of obesity, since its application leads to a significant reduction in body weight in animals and in people with a deficit of this hormone. This has led to the development of clinically appropriate product leptin, which has entered the third phase of clinical trial.