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J Physiol. 2004 Jul 1;558(Pt 1):147-59. Epub 2004 May 14.

The mammalian amiloride-insensitive non-specific salt taste receptor is a vanilloid receptor-1 variant.

Author information

1
Department of Physiology, Virginia Commonwealth University, Richmond, VA 23298-0551, USA. vlyall@hsc.vcu.edu

Abstract

The amiloride-insensitive salt taste receptor is the predominant transducer of salt taste in some mammalian species, including humans. The physiological, pharmacological and biochemical properties of the amiloride-insensitive salt taste receptor were investigated by RT-PCR, by the measurement of unilateral apical Na+ fluxes in polarized rat fungiform taste receptor cells and by chorda tympani taste nerve recordings. The chorda tympani responses to NaCl, KCl, NH4Cl and CaCl2 were recorded in Sprague-Dawley rats, and in wild-type and vanilloid receptor-1 (VR-1) knockout mice. The chorda tympani responses to mineral salts were monitored in the presence of vanilloids (resiniferatoxin and capsaicin), VR-1 antagonists (capsazepine and SB-366791), and at elevated temperatures. The results indicate that the amiloride-insensitive salt taste receptor is a constitutively active non-selective cation channel derived from the VR-1 gene. It accounts for all of the amiloride-insensitive chorda tympani taste nerve response to Na+ salts and part of the response to K+, NH4+ and Ca2+ salts. It is activated by vanilloids and temperature (> 38 degrees C), and is inhibited by VR-1 antagonists. In the presence of vanilloids, external pH and ATP lower the temperature threshold of the channel. This allows for increased salt taste sensitivity without an increase in temperature. VR-1 knockout mice demonstrate no functional amiloride-insensitive salt taste receptor and no salt taste sensitivity to vanilloids and temperature. We conclude that the mammalian non-specific salt taste receptor is a VR-1 variant.

PMID:
15146042
PMCID:
PMC1664927
DOI:
10.1113/jphysiol.2004.065656
[Indexed for MEDLINE]
Free PMC Article

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