Bitter taste receptors

Hundreds of bitter substances, synthetic or natural, toxic or health beneficial, chemically complex organic molecules or simple inorganic metal salts, surround us and other vertebrates. Their detection is mediated by bitter taste receptors present in the oral cavity and beyond. The present review article summarizes the current knowledge about these highly versatile receptors in humans and other vertebrates. Following the introductory description of taste anatomy and canonical taste signal transduction, a brief section about bitter compounds provides a flavor of their chemical diversity. The main part of the article is devoted to the human bitter taste receptors, their agonist profiles, structures, and sensitivities. For comparison, a section of bitter taste receptors in other species is added, and, to highlight the functional complexity of these molecules, nongustatory bitter taste receptors and their functions are described.