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.
- Almers W., Stanfield P. R., Stühmer W. Lateral distribution of sodium and potassium channels in frog skeletal muscle: measurements with a patch-clamp technique. J Physiol. 1983 Mar;336:261–284. doi: 10.1113/jphysiol.1983.sp014580. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Avenet P., Hofmann F., Lindemann B. Transduction in taste receptor cells requires cAMP-dependent protein kinase. Nature. 1988 Jan 28;331(6154):351–354. doi: 10.1038/331351a0. [DOI] [PubMed] [Google Scholar]
- BEIDLER L. M. A theory of taste stimulation. J Gen Physiol. 1954 Nov 20;38(2):133–139. doi: 10.1085/jgp.38.2.133. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Cummings T. A., Delay R. J., Roper S. D. Ultrastructure of apical specializations of taste cells in the mudpuppy, Necturus maculosus. J Comp Neurol. 1987 Jul 22;261(4):604–615. doi: 10.1002/cne.902610411. [DOI] [PubMed] [Google Scholar]
- Kinnamon S. C., Roper S. D. Membrane properties of isolated mudpuppy taste cells. J Gen Physiol. 1988 Mar;91(3):351–371. doi: 10.1085/jgp.91.3.351. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kinnamon S. C., Roper S. D. Passive and active membrane properties of mudpuppy taste receptor cells. J Physiol. 1987 Feb;383:601–614. doi: 10.1113/jphysiol.1987.sp016431. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Roper S. Regenerative impulses in taste cells. Science. 1983 Jun 17;220(4603):1311–1312. doi: 10.1126/science.6857254. [DOI] [PubMed] [Google Scholar]
- Sato T. Recent advances in the physiology of taste cells. Prog Neurobiol. 1980;14(1):25–67. doi: 10.1016/0301-0082(80)90003-9. [DOI] [PubMed] [Google Scholar]
- Tonosaki K., Funakoshi M. Cyclic nucleotides may mediate taste transduction. Nature. 1988 Jan 28;331(6154):354–356. doi: 10.1038/331354a0. [DOI] [PubMed] [Google Scholar]