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 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.

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 Genes for Taste Receptors. Isolation of a Gene for a Sour Taste Receptor.

2000 ◽  
Vol 40 (2) ◽  
pp. 105-110
Author(s):  
Shinya UGAWA ◽  
Shoichi SHIMADA
Keyword(s):  
Taste Receptor ◽  
Taste Receptors ◽  
Sour Taste

Sour taste: receptors, cells and circuits

2021 ◽  
Vol 20 ◽  
pp. 8-15
Author(s):  
Emily R Liman ◽  
Sue C Kinnamon
Keyword(s):  
Taste Receptors ◽  
Sour Taste

scholarly journals Screening of 5- and 6-Substituted Amiloride Libraries Identifies Dual-uPA/NHE1 Active and Single Target-Selective Inhibitors

2021 ◽  
Vol 22 (6) ◽  
pp. 2999
Author(s):  
Benjamin J. Buckley ◽  
Ashna Kumar ◽  
Ashraf Aboelela ◽  
Richard S. Bujaroski ◽  
Xiuju Li ◽  
...  
Keyword(s):  
Selectivity Ratio ◽  
Dual Targeting ◽  
Sodium Hydrogen ◽  
Type Plasminogen Activator ◽  
Single Target ◽  
Urokinase Type Plasminogen Activator ◽  
Anti Cancer ◽  
Sodium Hydrogen Exchanger ◽  
A Cell ◽  
Cell Invasiveness

The K+-sparing diuretic amiloride shows off-target anti-cancer effects in multiple rodent models. These effects arise from the inhibition of two distinct cancer targets: the trypsin-like serine protease urokinase-type plasminogen activator (uPA), a cell-surface mediator of matrix degradation and tumor cell invasiveness, and the sodium-hydrogen exchanger isoform-1 (NHE1), a central regulator of transmembrane pH that supports carcinogenic progression. In this study, we co‑screened our library of 5- and 6-substituted amilorides against these two targets, aiming to identify single-target selective and dual-targeting inhibitors for use as complementary pharmacological probes. Closely related analogs substituted at the 6-position with pyrimidines were identified as dual-targeting (pyrimidine 24 uPA IC50 = 175 nM, NHE1 IC50 = 266 nM, uPA selectivity ratio = 1.5) and uPA-selective (methoxypyrimidine 26 uPA IC50 = 86 nM, NHE1 IC50 = 12,290 nM, uPA selectivity ratio = 143) inhibitors, while high NHE1 potency and selectivity was seen with 5-morpholino (29 NHE1 IC50 = 129 nM, uPA IC50 = 10,949 nM; NHE1 selectivity ratio = 85) and 5-(1,4-oxazepine) (30 NHE1 IC50 = 85 nM, uPA IC50 = 5,715 nM; NHE1 selectivity ratio = 67) analogs. Together, these amilorides comprise a new toolkit of chemotype-matched, non-cytotoxic probes for dissecting the pharmacological effects of selective uPA and NHE1 inhibition versus dual-uPA/NHE1 inhibition.

scholarly journals Phosphoproteomic Analysis of Two Contrasting Maize Inbred Lines Provides Insights into the Mechanism of Salt-Stress Tolerance

2019 ◽  
Vol 20 (8) ◽  
pp. 1886 ◽  
Author(s):  
Xiaoyun Zhao ◽  
Xue Bai ◽  
Caifu Jiang ◽  
Zhen Li
Keyword(s):  
Salt Stress ◽  
Inbred Line ◽  
Carbon Metabolism ◽  
Phosphoenolpyruvate Carboxykinase ◽  
Glutathione Metabolism ◽  
Label Free ◽  
Plasma Membrane Intrinsic Protein ◽  
Sodium Hydrogen ◽  
Salt Response ◽  
Sodium Hydrogen Exchanger

Salinity is a major abiotic stress that limits maize yield and quality throughout the world. We investigated phosphoproteomics differences between a salt-tolerant inbred line (Zheng58) and a salt-sensitive inbred line (Chang7-2) in response to short-term salt stress using label-free quantitation. A total of 9448 unique phosphorylation sites from 4116 phosphoproteins in roots and shoots of Zheng58 and Chang7-2 were identified. A total of 209 and 243 differentially regulated phosphoproteins (DRPPs) in response to NaCl treatment were detected in roots and shoots, respectively. Functional analysis of these DRPPs showed that they were involved in carbon metabolism, glutathione metabolism, transport, and signal transduction. Among these phosphoproteins, the expression of 6-phosphogluconate dehydrogenase 2, pyruvate dehydrogenase, phosphoenolpyruvate carboxykinase, glutamate decarboxylase, glutamate synthase, l-gulonolactone oxidase-like, potassium channel AKT1, high-affinity potassium transporter, sodium/hydrogen exchanger, and calcium/proton exchanger CAX1-like protein were significantly regulated in roots, while phosphoenolpyruvate carboxylase 1, phosphoenolpyruvate carboxykinase, sodium/hydrogen exchanger, plasma membrane intrinsic protein 2, glutathione transferases, and abscisic acid-insensitive 5-like protein were significantly regulated in shoots. Zheng58 may activate carbon metabolism, glutathione and ascorbic acid metabolism, potassium and sodium transportation, and the accumulation of glutamate to enhance its salt tolerance. Our results help to elucidate the mechanisms of salt response in maize seedlings. They also provide a basis for further study of the mechanism underlying salt response and tolerance in maize and other crops.

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