Document Detail

Acid-activated cation currents in rat vallate taste receptor cells.
MedLine Citation:
PMID:  12091539     Owner:  NLM     Status:  MEDLINE    
Sour taste is mediated by acids with the degree of sourness a function of proton concentration. Recently, several members of the acid-sensing ion channel subfamily (ASICs) were cloned from taste cells and proposed to mediate sour taste. However, it is not known whether sour responses in taste cells resemble the responses mediated by ASICs. Using the whole cell patch-clamp technique and Na(+) imaging, we have characterized responses to acid stimuli in isolated rat vallate taste cells. Citric acid (pH 5) induced a large, rapidly activating inward current in most taste cells tested. The response showed various degrees of desensitization with prolonged stimulation. Current amplitudes were pH dependent, and adapting with acidic bath solutions reduced subsequent responses to acid stimulation. Amiloride (100-500 microM) partially and reversibly suppressed the acid-induced current. The current-voltage relationship showed reversal potential near the Na(+) equilibrium potential, suggesting that the current is carried predominantly by Na(+). These data were consistent with Na(+) imaging experiments showing that acid stimulation resulted in increases in intracellular Na(+). Taken together, these data indicate that acid-induced currents in vallate taste cells share general properties with ASICs expressed in heterologous cells and sensory neurons that express ASIC subunits. The large amplitude of the current and its existence in a high percentage of taste cells imply that ASICs or ASIC-like channels may play a prominent role in sour-taste transduction.
Weihong Lin; Tatsuya Ogura; Sue C Kinnamon
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Publication Detail:
Type:  In Vitro; Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Journal of neurophysiology     Volume:  88     ISSN:  0022-3077     ISO Abbreviation:  J. Neurophysiol.     Publication Date:  2002 Jul 
Date Detail:
Created Date:  2002-07-01     Completed Date:  2002-09-06     Revised Date:  2008-11-21    
Medline Journal Info:
Nlm Unique ID:  0375404     Medline TA:  J Neurophysiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  133-41     Citation Subset:  IM    
Department of Anatomy and Neurobiology, Colorado State University, Fort Collins, 80523, USA.
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MeSH Terms
Amiloride / pharmacology
Cations / metabolism*
Chloride Channels / physiology
Citric Acid / pharmacology*
Electric Conductivity
Hydrogen-Ion Concentration
Ion Channels / drug effects*,  physiology*
Patch-Clamp Techniques
Rats, Sprague-Dawley
Receptors, Drug / physiology
Sensory Receptor Cells / physiology*
Sodium / metabolism
Taste / physiology*
Grant Support
Reg. No./Substance:
0/Cations; 0/Chloride Channels; 0/Ion Channels; 0/Receptors, Drug; 2609-46-3/Amiloride; 7440-23-5/Sodium; 77-92-9/Citric Acid

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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