THE PHYSIOLOGY AND BRAIN MECHANISMS OF FEEDING

This article is designed as an introduction to the major theoretical m odels in the field of regulation of eating behavior, and a selective r eview of relevant neurobiological data. We first critically consider t he paradigm of homeostasis as it relates to body energy content, and a rgue that additional theoretical constructs will he needed to account for the complexity of eating behavior in both nonhumans and humans. We then summarize some of the methods available to the neuroscientist in this area, and address some of their limitations. We review treatment s and potential mechanisms that increase food intake, including depriv ation, antimetabolites, norepinephrine, and several peptides including neuropeptide Y. We next review treatments that decrease food intake. including a variety of humoral, gastrointestinal, and pancreatic facto rs, as well as examine central pathways of satiety. This includes a di scussion of leptin and other potential anorectic agents. We conclude w ith a discussion of human obesity and anorexias, and prospects for pha rmacotherapy of earing disorders. We emphasize throughout that most re gions of the human brain probably make some contribution to feeding be havior, and so a focus on any one area of transmitter/hormone is an un realistic approach both in basic and applied areas.