ABSTRACT
Our ability to sense chemicals occurring in food and beverages relies on the operation of specialized epithelial cells called taste cells, found as clusters (taste buds) mainly in the oral cavity. Unlike other sensory cells, such as hair cells in the cochlea, taste cells differ from each other in terms of structural features. At least three main morphotypes are now recognized in mammalian taste buds: Type I, Type II and Type III. Each of them displays specific membrane properties (i.e. ion channels and receptors) as well as intracellular signalling pathways. Some of them are electrically excitable (Type II and Type III), whereas Type I seems to subserve a glialβlike role. They also differ in the way they communicate with nerve terminals: apparently, only Type III cells seem to be able to relay directly information via synaptic contacts, whereas the other types of cells may communicate through less specialized mechanisms, including ATP release through nonβconventional synapses. What is then the significance of these three cell types in the context of taste reception? Although it is not yet possible to draw any definitive conclusion, the emerging view is that functional diversity of taste cells might represent the basis for a βsensory processingβ circuitry designed to detect chemicals, as a whole. Copyright Β© 2011 John Wiley & Sons, Ltd.