Neuromediators and neuropeptides: the biomarkers for metabolic disturbances in obesity

The role of biogenic amines (serotonin, dopamine) and neuropeptides in regulation of energy homeostasis of the organism and their role as markers of metabolic disorders in obesity (Ob) in animal experimental models and in clinical observations is reviewed. The energy homeostasis of the body is controlled via competition of alternative regulatory mechanisms that are mainly localized in the hypothalamus (HT). At the level of aminergic regulation, these are the serotonin and dopamine systems; at the level of the peptidergic system, these are NPY/AgRP and POMC/CART-related peptides. Opioid and cannabinoid receptors and their endogenous ligands closely linked to peptidergic and aminergic regulatory subsystems of the central nervous system ensure the connection between the «metabolic» regulation loop responding to a deficit or excess of energy substrates the «hedonistic» one associated with the body’s perception of pleasure from food consumption. The response of peptidergic and aminergic HT neurons to food and hormonal signals originating from the outside is based on the interaction between the corresponding ligands and G-protein-coupled receptors specific to them. Disruption or breakdown of the central mechanisms is considered to be one of the main pathogenetic factors of obesity and, simultaneously, the reason why reducing diet therapy proves inefficient or unstable. Partial permeability of the blood—brain barrier for neuropeptides makes them an attractive biomarker in the diagnosis of metabolic abnormalities in obese patients.