Taste: Cellular Basis

Abstract

Taste is the sense that detects the chemical composition of foodstuffs. Taste is initiated in peripheral sensory organs termed taste buds. Chemical stimuli in the oral cavity are sensed by receptor cells in taste buds, which transit information to primary sensory afferents and on to higher centres in the brain.

Keywords: gustation; chemosensory transduction; taste bud; receptors; orbitofrontal cortex

Figure 1.

Henning's 1916 taste tetrahedron. Tastes are represented as points situated between the four primary qualities: sweet, salty, sour and bitter. For example, the taste of grapefruit (shaded circular spot) might be represented as the combination of sour, bitter and sweet.

Figure 2.

Schematic representation of a taste bud embedded in the stratified squamous epithelium of the tongue. A single taste bud contains 50–100 cells, which include receptor cells, stem cells and possibly sustentacular cells.

Figure 3.

Summary of chemosensory transduction mechanisms believed to operate in mammalian taste bud cells: (a) transduction pathways for receptor‐coupled taste stimuli; (b) transduction pathways for taste stimuli that permeate or modulate ion channels. Not all taste transduction mechanisms are included in these schemes, such as those for K+ and NH4+ salts. Also, there is evidence in fish taste buds for direct ligand‐gated ion channels for certain amino acids. Steps that remain to be demonstrated experimentally are in italics. For example, although neurotransmitters are believed to be released from taste cells and excite primary afferent fibres, to date no transmitter(s) has been identified. Thus in the chemosensory pathways listed below, the release of neurotransmitter is italicized. Abbreviations: AC, adenylyl cyclase; AMP, adenosine monophosphate; ASSC, amiloride‐sensitive sodium channel; cAMP, cyclic adenosine monophosphate; cGMP, cyclic guanosine monophosphate; DAG, diacylglycerol; GMP, guanosine monophosphate; IP3, inositol triphosphate; PDE, phosphodiesterase; PKA, phosphokinase A; PLC, phospholipase C; VGCC, voltage‐gated Ca2+ channel.

Figure 4.

Summary of the taste axis, from peripheral sensory organs (taste buds) to the cerebral cortex. Sensory information from taste buds ascends to the primary gustatory cortex and association cortices. Not shown are descending (efferent) pathways believed to exist at several levels in the taste axis.

close

References

Akabas MH, Dood J and Al‐Awqati Q (1988) A bitter substance induces a rise in intracellular calcium in a subpopulation of rat taste cells. Science 242: 1047–1050.

Bernhardt SJ, Naim M, Zehavi U and Lindemann B (1996) Changes in IP3 and cytosolic Ca2+ in response to sugars and non‐sugar sweeteners in transduction of sweet taste in the rat. Journal of Physiology 490: 325–336.

Chaudhari N, Yang H, Lamp C, Delay E, Cartford C, Than T and Roper S (1996) The taste of MSG: membrane receptors in taste buds. Journal of Neuroscience 16: 3817–3826.

Cummings TA and Kinnamon SC (1992) Apical K+ channels in Necturus taste cells. Modulation by intracellular factors and taste stimuli. Journal of General Physiology 99: 591–613.

Gilbertson TA, Roper SD and Kinnamon SC (1993) Proton currents through amiloride‐sensitive Na channels in isolated hamster taste cells: enhancement by vasopressin and cAMP. Neuron 10: 931–942.

Hayashi Y, Zviman MM, Brand JG, Teeter JH and Restrepo D (1996) Measurement of membrane potential and [Ca2+]i in cell ensembles: application to the study of glutamate taste in mice. Biophysical Journal 71: 1057–1070.

Heck GL, Mierson S and DeSimone JA (1984) Salt taste transduction occurs through an amiloride‐sensitive sodium transport pathway. Science 223: 403–405.

Hoon MA, Adler E, Lindemeier J, Battey JF, Ryba NJ and Zuker CS (1999) Putative mammalian taste receptors: A class of taste‐specific GPCRs with distinct topographic selectivity. Cell 96: 541–551.

Kretz O, Barbry P, Bock R and Lindemann B (1999) Differential expression of RNA and protein of the three pore‐forming subunits of the amiloride‐sensitive epithelial sodium channel in taste buds of the rat. Journal of Histochemistry and Cytochemistry 47: 51–64.

McLaughlin SK, McKinnon RJ and Margolskee RF (1992) Gustducin is a taste‐specific G protein closely related to the transducins. Nature 357: 563–568.

Rosenzweig S, Yan W, Dasso M and Spielman AI (1999) Possible novel mechanism for bitter taste mediated through cGMP. Journal of Neurophysiology 81: 1661–1665.

Ruiz‐Avila L, McLaughlin SK, Wildman D et al. (1995) Coupling of bitter receptor to phosphodiesterases through transducin in taste receptor cells. Nature 376: 80–85.

Striem BJ, Pace U, Zehave U, Naim M and Lancet D (1989) Sweet tastants stimulate adenylate cyclase coupled to GTP binding protein in rat tongue membranes. Biochemical Journal 260: 121–126.

Ugawa S, Minami Y, Guo W, Saishin Y, Takatsuji K, Yamamoto T, Tohyama M and Shimada S (1998) Receptor that leaves a sour taste in the mouth. Nature 395 (6702): 555–556.

Further Reading

Doty RL (ed.) (1995) Handbook of Olfaction and Gustation. New York: Marcel Dekker.

Getchell TV, Bartoshuk LM, Doty RL and Snow J (eds) (1991) Smell and Taste in Health and Disease. New York: Raven Press.

Gilbertson TA (1998) Peripheral mechanisms of taste. In: Linden RWA (ed.) The Scientific Basis of Eating. Frontiers in Oral Biology 9: 1–28. Basel: Karger.

Kinnamon SC and Margolskee RF (1996) Mechanisms of taste transduction. Current Opinion in Neurobiology 6: 506–513.

Lindemann B (1996) Taste reception. Physiological Reviews 76: 718–766.

Rolls ET (1997) Taste and olfactory processing in the brain and its relation to the control of eating. Critical Reviews in Neurobiology 11: 263–287.

Roper SD (1992) The microphysiology of peripheral taste organs. Journal of Neuroscience 12: 1127–1134.

Simon SA and Roper SD (1993) Mechanisms of Taste Transduction. Boca Raton, FL: CRC Press.

Spielman AI (1998) Gustducin and its role in taste. Journal of Dental Research 77: 539–544.

Stewart RE, DeSimone JA and Hill DL (1997) New perspectives in a gustatory physiology: transduction, development, and plasticity. American Journal of Physiology 272: C1–C26.

Contact Editor close
Submit a note to the editor about this article by filling in the form below.

* Required Field

How to Cite close
Roper, Stephen D(Apr 2001) Taste: Cellular Basis. In: eLS. John Wiley & Sons Ltd, Chichester. http://www.els.net [doi: 10.1038/npg.els.0000216]