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Proceedings of the National Academy of Sciences of the United States of America logoLink to Proceedings of the National Academy of Sciences of the United States of America
. 1988 Sep;85(18):7023–7027. doi: 10.1073/pnas.85.18.7023

Apical localization of K+ channels in taste cells provides the basis for sour taste transduction.

S C Kinnamon 1, V E Dionne 1, K G Beam 1
PMCID: PMC282112  PMID: 2457924

Abstract

Previous studies have shown that mudpuppy taste receptor cells respond to sour taste stimuli (weak acids) with depolarizing receptor potentials or action potentials that are blocked by the K+ channel blocker tetraethylammonium. Voltage-clamp recordings from isolated taste cells indicated that taste receptor cells exhibit a variety of voltage-dependent conductances and that acids reduce a voltage-dependent K+ current. Since taste stimuli are restricted to the apical surface of the intact tongue, only 1-2% of the taste receptor cell surface is exposed to chemical stimuli. Thus, modification of a K+ conductance would be an effective transduction mechanism in receptor cells only if the majority of K+ channels were located on the apical membrane. We have used a combination of "loose-patch" and whole-cell recording methods to map the distribution of voltage-sensitive K+ and Na+ channels on dissociated Necturus maculosus taste cells. We report here that the K+ conductance is approximately equal to 50-fold greater on apical membrane than on basolateral membrane, whereas the Na+ conductance is distributed evenly. The marked nonuniformity of the voltage-sensitive K+ conductance, together with the block of this conductance by sour stimuli, indicates that K+ current modulation is the mechanism of sour taste transduction.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

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