Neurochemistry of the gustatory system

D. V. Smith, John Boughter

Research output: Chapter in Book/Report/Conference proceedingChapter

4 Citations (Scopus)

Abstract

The sense of taste is mediated by receptor mechanisms that are distributed on modified epithelial cells within structures called taste buds, which are located on the tongue and other parts of the oral cavity. These cells are innervated by branches of one of three cranial nerves, including the chorda tympani and greater superficial petrosal branches of VII, the lingual-tonsillar branch of IX, and the superior laryngeal branch of X. These nerves project into the rostral portion of the nucleus of the solitary tract (NST) of the medulla. Gustatory information is carried from there to oral motor circuits within the brainstem and to the parabrachial nuclei (PbN) of the pons, from which pathways arise to thalamus and insular cortex and also into areas of the limbic forebrain, including the lateral hypothalamus (LH), central nucleus of the amygdala (CeA), and the bed nucleus of the stria terminalis (BST). Taste buds contain cells that can be classified into types on ultrastructural grounds and these in turn have been shown to exhibit expression of a wide array of molecules, many of which are characteristic of a particular cell type. The transduction of chemical stimuli by taste receptor cells is mediated by several different mechanisms. Salts and acids interact directly with ion channels to depolarize receptor cells, whereas sweet- and bitter-tasting stimuli and amino acids interact with G-protein-coupled receptors of the T1R and T2R families, linked to second-messenger pathways. Although some of these receptors appear to be segregated into different cells, the electrophysiological and calcium imaging data show that taste bud cells are often responsive to stimuli of more than one quality. This multiple sensitivity is evident to an even greater degree in first-order nerve fibers and in central gustatory neurons, due to convergence of afferent input onto higher-order neurons. Afferent input into the NST appears to be mediated by glutamate and most second-order neurons are maintained under tonic GABAergic inhibition. Some of the neurons in the NST are excited by substance P and some are inhibited by met-enkephalin. Areas of the forebrain that receive gustatory input, including the insular cortex, LH, CeA, and BST, provide descending modulatory control over taste neurons in both the NST and PbN.

Original languageEnglish (US)
Title of host publicationHandbook of Neurochemistry and Molecular Neurobiology
Subtitle of host publicationSensory Neurochemistry
PublisherSpringer US
Pages109-135
Number of pages27
ISBN (Print)9780387303499
DOIs
StatePublished - Dec 1 2007

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Neurochemistry
Neurons
Solitary Nucleus
Taste Buds
Lateral Hypothalamic Area
Septal Nuclei
Prosencephalon
Tongue
Cerebral Cortex
Methionine Enkephalin
Second Messenger Systems
Substance P
G-Protein-Coupled Receptors
Ion Channels
Glutamic Acid
Vagus Nerve
Pons
Cranial Nerves
Salts
Thalamus

All Science Journal Classification (ASJC) codes

  • Neuroscience(all)
  • Biochemistry, Genetics and Molecular Biology(all)

Cite this

Smith, D. V., & Boughter, J. (2007). Neurochemistry of the gustatory system. In Handbook of Neurochemistry and Molecular Neurobiology: Sensory Neurochemistry (pp. 109-135). Springer US. https://doi.org/10.1007/978-0-387-30374-1_5

Neurochemistry of the gustatory system. / Smith, D. V.; Boughter, John.

Handbook of Neurochemistry and Molecular Neurobiology: Sensory Neurochemistry. Springer US, 2007. p. 109-135.

Research output: Chapter in Book/Report/Conference proceedingChapter

Smith, DV & Boughter, J 2007, Neurochemistry of the gustatory system. in Handbook of Neurochemistry and Molecular Neurobiology: Sensory Neurochemistry. Springer US, pp. 109-135. https://doi.org/10.1007/978-0-387-30374-1_5
Smith DV, Boughter J. Neurochemistry of the gustatory system. In Handbook of Neurochemistry and Molecular Neurobiology: Sensory Neurochemistry. Springer US. 2007. p. 109-135 https://doi.org/10.1007/978-0-387-30374-1_5
Smith, D. V. ; Boughter, John. / Neurochemistry of the gustatory system. Handbook of Neurochemistry and Molecular Neurobiology: Sensory Neurochemistry. Springer US, 2007. pp. 109-135
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