Suppression of central taste transmission by oral capsaicin

Christopher T. Simons, Yves Boucher, Earl Carstens

Research output: Contribution to journalArticle

40 Scopus citations

Abstract

Because intraoral capsaicin is reported to reduce the perceived intensity of certain taste qualities, we investigated whether it affects the central processing of gustatory information. The responses of gustatory neurons in the nucleus tractus solitarius (NTS) to tastant stimuli were recorded before and after lingual application of capsaicin in anesthetized rats. Thirty-four NTS units were characterized as responding best to sucrose (0.3 M), NaCl (0.1 M), citric acid (0.03 M), monosodium glutamate (0.2 M), or quinine (0.001 M). During lingual application of 330 μM capsaicin for 7 min, the firing rate increased for five units and decreased for four units; the remainder were unaffected. Immediately after capsaicin, responses to each tastant were in nearly all cases depressed (mean, 61.5% of control), followed by recovery in most cases. NTS tastant-evoked unit responses were unaffected by lingual application of vehicle (5% ethanol). Capsaicin elicited an equivalent reduction (to 64.5%) in tastant-evoked responses of nine additional NTS units recorded in rats with bilateral trigeminal ganglionectomy, arguing against a trigeminally mediated central effect. Furthermore, capsaicin elicited a puncate pattern of plasma extravasation in the tongue that matched the distribution of fungiform papillae. These results support a peripheral site of capsaicin suppression of taste possibly via direct or indirect effects on taste transduction or taste receptor cell excitability. The depressant effect of capsaicin on gustatory transmission might underlie its ability to reduce the perceived intensity of some taste qualities.

Original languageEnglish (US)
Pages (from-to)978-985
Number of pages8
JournalJournal of Neuroscience
Volume23
Issue number3
StatePublished - Feb 1 2003

Keywords

  • Capsaicin
  • Gustatory
  • Irritation
  • Nucleus of the solitary tract
  • Rat
  • Taste
  • Trigeminal

ASJC Scopus subject areas

  • Neuroscience(all)

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  • Cite this

    Simons, C. T., Boucher, Y., & Carstens, E. (2003). Suppression of central taste transmission by oral capsaicin. Journal of Neuroscience, 23(3), 978-985.