Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0235290 (bitter taste)
 1,408 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The apically restricted, voltage-dependent K+ conductance of Necturus taste receptor cells was studied using cell-attached, inside-out and outside-out configurations of the patch-clamp recording technique. Patches from the apical membrane typically contained many channels with unitary conductances ranging from 30 to 175 pS in symmetrical K+ solutions. Channel density was so high that unitary currents could be resolved only at negative voltages; at positive voltages patch recordings resembled whole-cell recordings. These multi-channel patches had a small but significant resting conductance that was strongly activated by depolarization. Patch current was highly K+ selective, with a PK/PNa ratio of 28. Patches containing single K+ channels were obtained by allowing the apical membrane to redistribute into the basolateral membrane with time. Two types of K+ channels were observed in isolation. Ca(2+)-dependent channels of large conductance (135-175 pS) were activated in cell-attached patches by strong depolarization, with a half-activation voltage of approximately -10 mV. An ATP-blocked K+ channel of 100 pS was activated in cell-attached patches by weak depolarization, with a half-activation voltage of approximately -47 mV. All apical K+ channels were blocked by the sour taste stimulus citric acid directly applied to outside-out and perfused cell-attached patches. The bitter stimulus quinine also blocked all channels when applied directly by altering channel gating to reduce the open probability. When quinine was applied extracellularly only to the membrane outside the patch pipette and also to inside-out patches, it produced a flickery block. Thus, sour and bitter taste stimuli appear to block the same apical K+ channels via different mechanisms to produce depolarizing receptor potentials.
J Gen Physiol 1992 Apr
PMID:Apical K+ channels in Necturus taste cells. Modulation by intracellular factors and taste stimuli. 159 80

The voltage-dependent currents of isolated Necturus lingual cells were studied using the whole-cell configuration of the patch-clamp technique. Nongustatory surface epithelial cells had only passive membrane properties. Small, spherical cells resembling basal cells responded to depolarizing voltage steps with predominantly outward K+ currents. Taste receptor cells generated both outward and inward currents in response to depolarizing voltage steps. Outward K+ currents activated at approximately 0 mV and increased almost linearly with increasing depolarization. The K+ current did not inactivate and was partially Ca++ dependent. One inward current activated at -40 mV, reached a peak at -20 mV, and rapidly inactivated. This transient inward current was blocked by tetrodotoxin (TTX), which indicates that it is an Na+ current. The other inward current activated at 0 mV, peaked at 30 mV, and slowly inactivated. This more sustained inward current had the kinetic and pharmacological properties of a slow Ca++ current. In addition, most taste cells had inwardly rectifying K+ currents. Sour taste stimuli (weak acids) decreased outward K+ currents and slightly reduced inward currents; bitter taste stimuli (quinine) reduced inward currents to a greater extent than outward currents. It is concluded that sour and bitter taste stimuli produce depolarizing receptor potentials, at least in part, by reducing the voltage-dependent K+ conductance.
J Gen Physiol 1988 Mar
PMID:Membrane properties of isolated mudpuppy taste cells. 245 84

The chincona alkaloid quinine is known to be a bitter tasting substance for various vertebrates. We examined the effects of quinine on isolated taste receptor cells from the bullfrog (Rana catesbeiana). Membrane currents were recorded by whole-cell recording, while quinine hydrochloride was applied extracellularly from a puffer pipette. At the resting potential (-77 +/- 9 mV, mean +/- SD, n = 49 cells), taste cells generated inward currents in response to quinine stimulation (> 1 mM), indicating a depolarizing response in the taste cells. Two types of current responses were observed; a newly found quinine-activated cationic conductance and a previously reported blocking effect of quinine on K+ conductances. The cationic current was isolated from the K+ current by using a Cs(+)-containing patch pipette. The relative permeabilities (Pion) of the quinine-activated cationic conductance were: PNa/PK/PCs = 1:0.5:0.42. The quinine dose-response relation was described by the Hill equation with the K1/2 of 3.6 mM and Hill coefficient of 5.3. When extracellular [Ca2+] (1.8 mM) was reduced to nominally free, the conductance was enhanced by about sixfold. This property is consistent with observations on quinine responses recorded from the gustatory nerve, in vivo. The quinine-induced cationic current was decreased with an application of 8-bromo-cAMP. We conclude that the bitter substance quinine activates a cation channel in taste receptor cells and this channel plays an important role in bitter taste transduction.
J Gen Physiol 1996 Dec
PMID:A quinine-activated cationic conductance in vertebrate taste receptor cells. 897 89

Bitter taste receptors (TAS2Rs or T2Rs) belong to the superfamily of seven-transmembrane G protein-coupled receptors, which are the targets of >50% of drugs currently on the market. Canonically, T2Rs are located in taste buds of the tongue, where they initiate bitter taste perception. However, accumulating evidence indicates that T2Rs are widely expressed throughout the body and mediate diverse nontasting roles through various specialized mechanisms. It has also become apparent that T2Rs and their polymorphisms are associated with human disorders. In this review, we summarize the physiological and pathophysiological roles that extraoral T2Rs play in processes as diverse as innate immunity and reproduction, and the major challenges in this emerging field.
J Gen Physiol 2017 Feb
PMID:Extraoral bitter taste receptors in health and disease. 2805 91

In English, unfair treatment and social injustice are often described as "bitter" experiences, whereas "eating bitterness" refers to endurance in the face of hardship in Chinese. This suggests that bitter taste may ground experiences of adversity in both cultures, but in culture-specific forms. We tested this possibility by assessing Canadian and Chinese participants' responses to fairness and achievement scenarios after incidental exposure to bitter or neutral tastes. Tasting something bitter increased self-reported motivation and intention to invest effort for Chinese participants, but not Anglo-Canadian participants (Studies 1, 4, 5). Tasting something bitter decreased perceived fairness for Anglo-Canadian participants (Studies 1-3) but not Chinese participants living in China (Study 2). The fairness judgments of Chinese participants living in Canada shed light on adaptation to the host culture: Bitter taste decreased these participants' fairness judgments after living in Canada for 4 years or more (Study 4), provided they were tested in English (Studies 3-4), but exerted no influence when they were tested in Chinese (Study 4). The observed cultural differences are compatible with a relatively higher emphasis on self-improvement in China versus self-enhancement in Canada. Supporting this conjecture, the fairness judgments of Chinese students in Canada followed the Anglo-Canadian pattern when primed with a self-enhancement motive and the effort judgments of Anglo-Canadian students followed the Chinese pattern when primed with a self-improvement motive (Study 5). This suggest that a universal aversive experience (bitter taste) grounds thought about adversity in ways compatible with cultural orientations and reflected in culture-specific metaphors. (PsycInfo Database Record (c) 2020 APA, all rights reserved).
J Exp Psychol Gen 2020 Oct 29
PMID:"That's bitter!": Culture-specific effects of gustatory experience on judgments of fairness and advancement. 3311 58