When an excessive proportion of the human energy requirement is derived from fat, the likelihood of obesity increases. Any such individual is at risk for diabetes and cardiovascular disease- grave and costly health hazards. The selective control of fat ingestion is a promising solution to these concerns. Existing data suggests that macronutrient intake can be manipulated. Further research is working to create pharmacological tools that will suppress fat consumption. It will also be possible to fight obesity, heart disease and diabetes. Neural and Metabolic Control of Macronutrient Intake systematically discusses the known physiological mechanisms involved in macronutrientselection, including their molecular, genetic and neurochemical aspects. The book is also a critical review of the hypothesis that ingestion of the three nutrients is regulated by separate neural control mechanisms, leaving open the possibility that strategies could be devised to intervene in bodily control systems and alter the proportion of fat in the diet. This reference provides three types of information: First, the basic background of the biochemical and physiological systems as they relate to macronutrient selection. Second, opinions and data concerning to what degree animals and humans show evidence of macronutrient selection. And, third, evidence about how the central nervous system might be involved in the choices animals make among macronutrients.

When an excessive proportion of the human energy requirement is derived from fat, the likelihood of obesity increases. Any such individual is at risk for diabetes and cardiovascular disease- grave and costly health hazards. The selective control of fat ingestion is a promising solution to these concerns. Existing data suggests that macronutrient intake can be manipulated. Further research is working to create pharmacological tools that will suppress fat consumption. It will also be possible to fight obesity, heart disease and diabetes. Neural and Metabolic Control of Macronutrient Intake systematically discusses the known physiological mechanisms involved in macronutrientselection, including their molecular, genetic and neurochemical aspects. The book is also a critical review of the hypothesis that ingestion of the three nutrients is regulated by separate neural control mechanisms, leaving open the possibility that strategies could be devised to intervene in bodily control systems and alter the proportion of fat in the diet. This reference provides three types of information: First, the basic background of the biochemical and physiological systems as they relate to macronutrient selection. Second, opinions and data concerning to what degree animals and humans show evidence of macronutrient selection. And, third, evidence about how the central nervous system might be involved in the choices animals make among macronutrients.

1 Introduction The esophagus is a relatively simple though vital organ. It consists of a two-layered muscular tube whose lumen is lined by squamous strati?ed epithelium. Beyond its role of propelling food from the pharynx to the stomach by a propulsive contraction wave representing the esophageal phase of deglutition (Conklin and Christensen 1994; Jean 2001), it is more and more recognized as a sensory organ from which a variety of respiratory and cardiovascular re?exes can be triggered, thus coop- ating with the larynx in protecting the lower airways from aspiration (Barthelemy et al. 1996; Lang et al. 2002; Lang et al. 2001; Loomis et al. 1997; Medda et al. 2003). In ruminants, there is additional antiperistalsis for regurgitation. During emesis, the esophagus is a merely passive conduit except for some antiperistalsis in its upper part. In the interval between swallows, both oral and aboral ends of the esophagus are tonically closed by the upper and lower esophageal sphincters, UES and LES respectively, while the tubular esophagus is ?accid and partly ?lled with air. Despite this apparent simplicity, neuronal control of esophageal functions is quite complex.