Ion Pathways in the Taste Bud and their Significance for Transduction

  1. Derek Chadwick Organizer,
  2. Joan Marsh Organizer and
  3. Jamie Goode
  1. John A. Desimone,
  2. Qing Ye and
  3. Gerard L. Heck

Published Online: 28 SEP 2007

DOI: 10.1002/9780470514511.ch14

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

Desimone, J. A., Ye, Q. and Heck, G. L. (2007) Ion Pathways in the Taste Bud and their Significance for 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.ch14

Author Information

  1. Department of Physiology, Box 55 1, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA 23298-0551, USA

Publication History

  1. Published Online: 28 SEP 2007

ISBN Information

Print ISBN: 9780471939467

Online ISBN: 9780470514511

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Keywords:

  • ion pathways;
  • transduction;
  • taste bud;
  • Na+ concentration;
  • apical membrane channel conductance

Summary

Taste buds share a topology with ion-transporting epithelia and evidence now indicates that neural responses in rats to Na+ salts of differing anion are mediated by both transcellular and paracellular ion transport. Na+ exerts its effects mainly on the transcellular pathway. Neural responses to Na+ salts are enhanced by negative voltage clamp and suppressed by positive clamp in a manner indicating modulation of the apical membrane potential of receptor cells. Anion effects are mainly paracellular. Under zero current clamp increasing anion size reduces the neural response at constant Na+ concentration. Below about 50 mM this difference is entirely eliminated under voltage clamp. This suggests that paracellular transepithelial potentials normally create an anion difference. At higher concentrations the relatively high permeability of the paracellular shunt to Cl permits sufficient electroneutral diffusion of NaCl below the tight junctions to stimulate cells that do not make direct contact with the oral cavity. In general, the sensitivity of a response to perturbations in the apical membrane potential indicates that some phase of Na+ salt taste transduction is accompanied by changes in an apical membrane channel conductance.