The role of the brain in energy balance and obesity.
Levin, Barry E., and Vanessa H. Routh.
Neurology Service, Department of Veterans Affairs Medical Center,
E. Orange 07018 and Department of Neurosciences, NJ, Medical School,
Newark, NJ 07103
APStracts 3:0213R, 1996.
Energy balance and body weight are regulated in short, intermediate
and long cycles which are superimposed upon each other. We propose
that the brain is the primary center of this regulation. The brain
has evolved mechanisms for sensing the energy status of the body
using neural and metabolic signals like glucose, insulin and leptin.
It has central processing and storage capacity for handling this
afferent information and can change both structurally and
functionally in response to its internal and external milieu. The
brain regulates energy balance through its control of energy intake
on the one hand and expenditure and storage on the other using
neurohumoral mechanisms which include the autonomic nervous system.
Work in animal models suggests that the obese brain largely ignores
signals of excess adiposity from the periphery keeping the body
weight setpoint at pathologically high levels. Disordered regulation
of neuropeptide Y and monoamine metabolism within the ventromedial
hypothalamus is a consistent finding in the brains of obesity-prone
and obese rodents. Such dysregulation causes inappropriate
neurohumoral control of metabolism and autonomic output to organs
such as the pancreas resulting in increased metabolic efficiency and
persistent adiposity. The high recidivism rate in the treatment of
obesity suggests that central disfunction may be due to long-term
reorganization of the nervous system in such a way as to perpetuate
the abnormally high setpoint of body weight.
Received 12 March 1996; accepted in final form 13 May 1996.
APS Manuscript Number R145-6.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 17 June 96