Central Nervous System Regulation of Energy Balance and Energy Stores

Abstract

The central nervous system regulates energy balance and energy stores. Several nuclei in the hypothalamus provide the core of this function, with input from other regions of the brain. The hypothalamus serves as an integrator of circulating and neuronal signals that reach the brain with current information on the energy state of the body. The major orexigenic signal from the periphery is ghrelin, which is made in the stomach during the fasting state. Neuropeptide Y neurons in the arcuate nucleus of the hypothalamus provide the major signaling for hunger and feeding. Orexin from the lateral hypothalamic area contributes to the generation of hunger. There are multiple peripheral anorexigenic signals, among which is leptin, one of the major hormones produced in adipose tissue. Pro-opiomelanocortin neurons in the arcuate nucleus of the hypothalamus provide the major signaling for fullness and cessation of feeding. The integration of these signals in the hypothalamus is modulated by heavy input from other areas of the brain.

In adiposopathy, overweight, and obesity, there is a chronic, tonic upregulation of orexigenic signals and downregulation of anorexigenic signals, including resistance to the effect of leptin, which leads to a positive energy balance. Over time, calories are stored in the body, with adipose tissue being the major storage organ for these excess calories. Bariatric endocrinology involves the study of these neurohormonal systems. Therapeutic options for the treatment of adiposopathy, overweight, and obesity will come from further understanding of the central control mechanisms of hunger and fullness.