Role of Apical Ion Channels in Sour Taste Transduction

  1. Derek Chadwick Organizer,
  2. Joan Marsh Organizer and
  3. Jamie Goode
  1. Sue C. Kinnamon1,2

Published Online: 28 SEP 2007

DOI: 10.1002/9780470514511.ch13

Ciba Foundation Symposium 179 - The Molecular Basis of Smell and Taste Transduction

Ciba Foundation Symposium 179 - The Molecular Basis of Smell and Taste Transduction

How to Cite

Kinnamon, S. C. (2007) Role of Apical Ion Channels in Sour Taste Transduction, in Ciba Foundation Symposium 179 - The Molecular Basis of Smell and Taste Transduction (eds D. Chadwick, J. Marsh and J. Goode), John Wiley & Sons, Ltd., Chichester, UK. doi: 10.1002/9780470514511.ch13

Author Information

  1. 1

    Department of Anatomy and Neurobiology, Colorado State University, Ft Collins, CO 80523

  2. 2

    Rocky Mountain Taste and Smell Center, University of Colorado Health Sciences Center, Denver, CO 80262, USA

Publication History

  1. Published Online: 28 SEP 2007

ISBN Information

Print ISBN: 9780471939467

Online ISBN: 9780470514511

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Keywords:

  • sour taste perception;
  • current flows;
  • conductance;
  • inhibition constant;
  • necturus maculosus

Summary

Sour taste perception depends primarily on the concentration of H+ in the taste stimulus. Acid stimuli elicit concentration-dependent action potentials in taste cells. Recent patch-clamp studies suggest that protons depolarize taste cells by direct interaction with apically located ion channels. In Necturus maculosus, the voltage-dependent K+ conductance is restricted to the apical membrane of taste cells. The current flows through a variety of K+ channels with unitary conductances ranging from 30 to 175 pS, all of which are blocked directly by citric acid applied to outside-out or perfused cell-attached patches. In contrast, hamster fungiform taste cells appear to utilize the amiloride-sensitive Na+ channel for acid transduction. Amiloride completely inhibits H+ currents elicited by acid stimuli in isolated taste cells, with an inhibition constant similar to that for amiloride-sensitive Na+ currents (Ki = 0.2 µM). Treatment of isolated taste cells with the bioactive peptide arginine8-vasopressin results in similar increases in both the amiloride-sensitive Na+ and H+ currents; the effect is mimicked by 8-bromocyclic AMP. These results suggest that H+ can permeate amiloride-sensitive Na+ channels in hamster fungiform taste cells, contributing to the transduction of sour stimuli.