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

2004 ◽  
Vol 558 (1) ◽  
pp. 147-159 ◽  
Author(s):  
Vijay Lyall ◽  
Gerard L. Heck ◽  
Anna K. Vinnikova ◽  
Shobha Ghosh ◽  
Tam-Hao T. Phan ◽  
...  
Keyword(s):  
Taste Receptor ◽  
Vanilloid Receptor ◽  
Salt Taste ◽  
Vanilloid Receptor 1

scholarly journals Ethanol Modulates the VR-1 Variant Amiloride-insensitive Salt Taste Receptor. I. Effect on TRC Volume and Na+ Flux

2005 ◽  
Vol 125 (6) ◽  
pp. 569-585 ◽  
Author(s):  
Vijay Lyall ◽  
Gerard L. Heck ◽  
Tam-Hao T. Phan ◽  
Shobha Mummalaneni ◽  
Shahbaz A. Malik ◽  
...  
Keyword(s):  
Taste Receptor ◽  
Na Channel ◽  
Mineral Salts ◽  
Tonic Component ◽  
Salt Taste ◽  
Vanilloid Receptor 1 ◽  
Intracellular Na Activity ◽  
Nerve Recordings ◽  
Epithelial Na Channel

The effect of ethanol on the amiloride- and benzamil (Bz)-insensitive salt taste receptor was investigated by the measurement of intracellular Na+ activity ([Na+]i) in polarized rat fungiform taste receptor cells (TRCs) using fluorescence imaging and by chorda tympani (CT) taste nerve recordings. CT responses were monitored during lingual stimulation with ethanol solutions containing NaCl or KCl. CT responses were recorded in the presence of Bz (a specific blocker of the epithelial Na+ channel [ENaC]) or the vanilloid receptor-1 (VR-1) antagonists capsazepine or SB-366791, which also block the Bz-insensitive salt taste receptor, a VR-1 variant. CT responses were recorded at 23°C or 42°C (a temperature at which the VR-1 variant salt taste receptor activity is maximally enhanced). In the absence of permeable cations, ethanol induced a transient decrease in TRC volume, and stimulating the tongue with ethanol solutions without added salt elicited only transient phasic CT responses that were insensitive to elevated temperature or SB-366791. Preshrinking TRCs in vivo with hypertonic mannitol (0.5 M) attenuated the magnitude of the phasic CT response, indicating that in the absence of mineral salts, transient phasic CT responses are related to the ethanol-induced osmotic shrinkage of TRCs. In the presence of mineral salts, ethanol increased the Bz-insensitive apical cation flux in TRCs without a change in cell volume, increased transepithelial electrical resistance across the tongue, and elicited CT responses that were similar to salt responses, consisting of both a transient phasic component and a sustained tonic component. Ethanol increased the Bz-insensitive NaCl CT response. This effect was further enhanced by elevating the temperature from 23°C to 42°C, and was blocked by SB-366791. We conclude that in the presence of mineral salts, ethanol modulates the Bz-insensitive VR-1 variant salt taste receptor.

Taste Receptors in the Gastrointestinal Tract III. Salty and sour taste: sensing of sodium and protons by the tongue

2006 ◽  
Vol 291 (6) ◽  
pp. G1005-G1010 ◽  
Author(s):  
John A. DeSimone ◽  
Vijay Lyall
Keyword(s):  
Food Selection ◽  
Taste Receptor ◽  
Taste Receptors ◽  
Sour Taste ◽  
Salt Taste ◽  
Taste Response ◽  
Sodium Hydrogen ◽  
Vanilloid Receptor 1 ◽  
Sodium Hydrogen Exchanger ◽  
Tonic Phase

Taste plays an essential role in food selection and consequently overall nutrition. Because salt taste is appetitive, humans ingest more salt than they need. Acids are the source of intrinsically aversive sour taste, but in mixtures with sweeteners they are consumed in large quantities. Recent results have provided fresh insights into transduction and sensory adaptation for the salty and sour taste modalities. The sodium-specific salt taste receptor is the epithelial sodium channel whereas a nonspecific salt taste receptor is a taste variant of the vanilloid receptor-1 nonselective cation channel, TRPV1. The proximate stimulus for sour taste is a decrease in the intracellular pH of a subset of acid-sensing taste cells, which serves as the input to separate transduction pathways for the phasic and tonic parts of the sour neural response. Adaptation to sour arises from the activation of the basolateral sodium-hydrogen exchanger isoform-1 by an increase in intracellular calcium that sustains the tonic phase of the sour taste response.

scholarly journals Regulation of the Putative TRPV1t Salt Taste Receptor by Phosphatidylinositol 4, 5-Bisphosphate

2010 ◽  
Vol 103 (3) ◽  
pp. 1337-1349 ◽  
Author(s):  
Vijay Lyall ◽  
Tam-Hao T. Phan ◽  
ZuoJun Ren ◽  
Shobha Mummalaneni ◽  
Pamela Melone ◽  
...  
Keyword(s):  
Monosodium Glutamate ◽  
Taste Receptor ◽  
Receptor Protein ◽  
Chorda Tympani ◽  
Sprague Dawley ◽  
Salt Taste ◽  
Sprague Dawley Rats ◽  
Enhanced Ct ◽  
Biphasic Effect ◽  
Phosphatidylinositol 4

Regulation of the putative amiloride and benzamil (Bz)-insensitive TRPV1t salt taste receptor by phosphatidylinositol 4,5-bisphosphate (PIP2) was studied by monitoring chorda tympani (CT) taste nerve responses to 0.1 M NaCl solutions containing Bz (5 × 10−6 M; a specific ENaC blocker) and resiniferatoxin (RTX; 0–10 × 10−6 M; a specific TRPV1 agonist) in Sprague-Dawley rats and in wildtype (WT) and TRPV1 knockout (KO) mice. In rats and WT mice, RTX elicited a biphasic effect on the NaCl + Bz CT response, increasing the CT response between 0.25 × 10−6 and 1 × 10−6 M. At concentrations >1 × 10−6 M, RTX inhibited the CT response. An increase in PIP2 by topical lingual application of U73122 (a phospholipase C blocker) or diC8-PIP2 (a short chain synthetic PIP2) inhibited the control NaCl + Bz CT response and decreased its sensitivity to RTX. A decrease in PIP2 by topical lingual application of phenylarsine oxide (a phosphoinositide 4 kinase blocker) enhanced the control NaCl + Bz CT response, increased its sensitivity to RTX stimulation, and inhibited the desensitization of the CT response at RTX concentrations >1 × 10−6 M. The ENaC-dependent NaCl CT responses were not altered by changes in PIP2. An increase in PIP2 enhanced CT responses to sweet (0.3 M sucrose) and bitter (0.01 M quinine) stimuli. RTX produced the same increase in the Bz-insensitive Na+response when present in salt solutions containing 0.1 M NaCl + Bz, 0.1 M monosodium glutamate + Bz, 0.1 M NaCl + Bz + 0.005 M SC45647, or 0.1 M NaCl + Bz + 0.01 M quinine. No effect of RTX was observed on CT responses in WT mice and rats in the presence of the TRPV1 blocker N-(3-methoxyphenyl)-4-chlorocinnamide (1 × 10−6 M) or in TRPV1 KO mice. We conclude that PIP2 is a common intracellular effector for sweet, bitter, umami, and TRPV1t-dependent salt taste, although in the last case, PIP2 seems to directly regulate the taste receptor protein itself, i.e., the TRPV1 ion channel or its taste receptor variant, TRPV1t.

Synthesis and evaluation of thiazole carboxamides as vanilloid receptor 1 (TRPV1) antagonists

2005 ◽  
Vol 15 (23) ◽  
pp. 5211-5217 ◽  
Author(s):  
Ning Xi ◽  
Yunxin Bo ◽  
Elizabeth M. Doherty ◽  
Christopher Fotsch ◽  
Narender R. Gavva ◽  
...  
Keyword(s):  
Vanilloid Receptor ◽  
Vanilloid Receptor 1

Local inflammation increases vanilloid receptor 1 expression within distinct subgroups of DRG neurons

2003 ◽  
Vol 963 (1-2) ◽  
pp. 190-196 ◽  
Author(s):  
Fumimasa Amaya ◽  
Kentaro Oh-hashi ◽  
Yoshihisa Naruse ◽  
Norio Iijima ◽  
Masashi Ueda ◽  
...  
Keyword(s):  
Vanilloid Receptor ◽  
Local Inflammation ◽  
Drg Neurons ◽  
Vanilloid Receptor 1
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