ABSTRACT
The aim of this chapter is to provide an overview of the molecular mechanisms involved in taste transduction. Human taste perception can be divided into five major categories: sweet, sour, salt, bitter, and umami (glutamate). Acids and sodium salts, which elicit sour and salt taste, respectively, are fluxed by and/or regulate the activities of ion channels expressed in taste receptor cells (TRCs). Sugars, artificial sweeteners, bitter plant alkaloids, and other bitter compounds primarily stimulate G protein-coupled receptors (GPCRs) to initiate one or more second messenger signaling cascades. Transduction of the taste of amino acids such as L-glutamate appears to depend on both GPCR cascades and stimulation of amino acid-gated ion channels. During the past 10 years major new insights in taste transduction have been gained from diverse studies utilizing electrophysiology, biochemistry, molecular cloning, and transgenic and gene knockout animal models.
