Mechanisms of the energy homeostasis of organism. Part I: Regulation on the level of the central nervous system

Abstract

The amount of energy delivered with food must be accurately adjusted to its expenditure. In the longer perspective, even a slight disorder of this balance leads to a change of body mass. The centers collecting information about the nutritional status of the body are specialized nuclei of the hypothalamus constituting axis of the homeostatic system. Within the area of the arcuate nucleus there are groups of neurons specialized in detection of signals about nutritional requirement (called NPY/AgRP from neuropeptide Y and Agouti-related protein synthetized by them) and about its delivery or the lack of requirement (called POMC/CART from proopiomelanocortin and cocaine- and amphetamine-regulated transcript synthetized by them). These signals are then futher processed by neurons located within the area of lateral, paraventricular, ventromedial and dorsomedial nuclei and sent to other areas of the brain, including neurons that the mesolimbic dopaminergic system (reward system) is consisted of. The opioid and endocannabinoid systems  which are the main components of the hedonistic system, play a key role in experiencing nutritional pleasure. Both systems (homeostatic and hedonistic) are connected with each other and constitute a functional whole. Eating disorders can be caused by improper functioning of its elements or communication between the very systems.