10 - The Search for Receptors That Mediate Sweetness

Abstract

This chapter provides an overview of the present knowledge of the receptors that mediate sweet taste. It emphasizes that no sweet receptor has ever been isolated nor are the physicochemical properties of molecules necessary to initiate a sweet sensation well understood. The most prominent theory to date is that a pair of simultaneous hydrogen bonds separated by approximately 3 Å is a necessary condition for sweetness. The investigations that shed light on the nature of sweet receptors derive from a range of disciplines including organic chemistry, biochemistry, neurophysiology, psychology, biophysics, and medicinal chemistry. The chapter discusses the following topics—(1) the chemical structure of sweeteners; (2) biochemical approaches to understanding sweet receptors; (3) the electrophysiological and behavioral approaches in animals; (4) the psychophysical studies in humans including data implicating sodium transport and adenosine receptors in sweet taste; and (5) computer-assisted molecular design—a new approach to design sweeteners.