Taste: Cellular Basis

Abstract

Abstract Taste buds are the peripheral end organs of the gustatory system. Several thousand of these sensory organs are distributed throughout the oral cavity. Each taste bud consists of up to 100 cells that detect food chemicals and transmit this information to sensory afferent fibres that connect taste buds to the hindbrain. Individual taste buds detect many compounds, including those that elicit sweet, salty, bitter, sour, umami and perhaps other perceptions. There is no taste map on the tongue. Sensory receptor cells in taste buds transduce taste stimuli using G protein‐coupled taste receptors and ion channels. Gustatory stimulation causes the taste bud cells to secrete neurotransmitters, including ATP and serotonin, that excite sensory afferent fibres as well as mediate cell–cell (paracrine) interactions within a taste bud. Taste information travels from the hindbrain to cortical centres where the signals are integrated with olfaction to generate perception of flavours. Key Concepts Taste buds respond to chemical compounds found in foods and beverages. Taste buds consist of many cells that are dedicated to sensing multiple tastes, including sweet, sour, salty, bitter and umami. There is no taste map on the tongue. Taste cells comprise a renewing cell population with taste cells having lifespans of 8–12 days. There are 4 major types of cells in taste buds, each having a distinct function. Gustatory stimulation causes taste bud cells to secrete ATP and serotonin. Taste‐evoked ATP release is highly unusual: it is nonvesicular and involves secretion through large‐pore ion channels. Cells within a taste bud communicate with each other during taste stimulation via paracrine synaptic interactions. Gustatory signals transmitted to the brain cortex converge there with olfactory input to generate flavours.