Role of apical ion channels in sour taste transduction

Ciba Found Symp. 1993;179:201-10; discussion 210-7. doi: 10.1002/9780470514511.ch13.


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 microM). Treatment of isolated taste cells with the bioactive peptide arginine-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.

Publication types

  • Research Support, U.S. Gov't, P.H.S.
  • Review

MeSH terms

  • Animals
  • Cricetinae
  • Ion Channels / physiology*
  • Membrane Potentials / physiology
  • Necturus
  • Potassium Channel Blockers*
  • Protons*
  • Signal Transduction / physiology*
  • Sodium Channels / drug effects
  • Taste / physiology*


  • Ion Channels
  • Potassium Channel Blockers
  • Protons
  • Sodium Channels