Interactions among adipose tissue, autonomic nervous system and orexinergic system

Adipose tissue is a biological caloric reservoir that expands in response to over-nutrition and releases lipids in response to energy deficit. It comprises white adipose tissue (WAT) and brown adipose tissue (BAT). WAT primarily stores energy as triglycerides, whereas BAT dissipates chemical energy as heat. BAT is a key site of heat production in mammals that has for many decades been considered an attractive target to promote weight loss. The regulation of the sympathetic nervous system (SNS) tone provides a complex homeostatic mechanism able to specifically coordinate the function and crosstalk of the organs involved in energy balance. Whereas the adaptive thermogenic response to cold and high-fat diet increases the SNS outflow to BAT; the different lipolytic requirements of these two conditions are appropriately met by the increase or decrease of the sympathetic outflow to selected WAT depots. Furthermore adipose tissue acts as an endocrine organ by producing various signalling cytokines, and interacting with some neuropeptides as orexins. This review reports our evidences showing that the autonomic nervous system controls body weight and fat mass (FM) by influencing food intake and energy consumption.