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At least 775 records · Page 43Linked to original sources
PubMed2000

In situ Ca2+ imaging reveals neurotransmitter receptors for glutamate in taste receptor cells.

The neurotransmitters at synapses in taste buds are not yet known with confidence. Here we report a new calcium-imaging technique for taste buds that allowed us to test for the presence of glutamate receptors (GluRs) in living isolated tissue preparations. Taste cells of rat foliate papillae were loaded with calcium green dextran (CaGD). Lingual slices containing CaGD-labeled taste cells were imaged with a scanning confocal microscope and superfused with glutamate (30 micromter to 1 mm), kainate (30 and 100 micrometer), AMPA (30 and 100 micrometer), or NMDA (100 micrometer). Responses were observed in 26% of the cells that were tested with 300 micrometer glutamate. Responses to glutamate were localized to the basal processes and cell bodies, which are synaptic regions of taste cells. Glutamate responses were dose-dependent and were induced by concentrations as low as 30 microm. The non-NMDA receptor antagonists CNQX and GYKI 52466 reversibly blocked responses to glutamate. Kainate, but not AMPA, also elicited Ca(2+) responses. NMDA stimulated increases in [Ca(2+)](i) when the bath medium was modified to optimize for NMDA receptor activation. The subset of cells that responded to glutamate was either NMDA-unresponsive (54%) or NMDA-responsive (46%), suggesting that there are presumably two populations of glutamate-sensitive taste cells-one with NMDA receptors and the other without NMDA receptors. The function of GluRs in taste buds is not yet known, but the data suggest that glutamate is a neurotransmitter there. GluRs in taste cells might be presynaptic autoreceptors or postsynaptic receptors at afferent or efferent synapses.

6-Cyano-7-nitroquinoxaline-2,3-dione↗
PubMed2000

Chlorhexidine and taste. Influence of mouthwashes concentration and of rinsing time.

BACKGROUND: This study aims to define the influence of chlorhexidine on taste, considering either its concentration in mouthwashes or time of rinsing. METHODS: Suprathreshold taste acuity of 40 healthy subjects tasting variously concentrated solutions of sucrose, sodium chloride, citric acid and quinine hydrochloride was determined. Subjects were divided into four groups. Three groups rinsed their mouths during one minute, twice a day, for seven days, with a selected mouthwash (respectively 0.12%, 0.20%, and 0.30% chlorhexidine solutions). The fourth group rinsed in the same manner with a 0.30% chlorhexidine mouthwash, and time of rinsing was 15". RESULTS: All the mouthwashes reduced taste acuity for salt and bitter; the perception of sweet and sour was not significantly modified. Chlorhexidine acted on taste in different ways: salt perception reached the lowest value on the second day of treatment and the degree of hypogeusia changed no more till mouthrinses were interrupted. Bitter perception was progressively reduced and reached the lowest value on the seventh day. In both cases taste reduction lasted some days after the interruption of mouthrinses. Quality of all tastes was altered by mouthwashes, but incidence of dysgeusia was not related to chlorhexidine concentration. CONCLUSIONS: Hypogeusia induced by chlorhexidine concerns specifically salt and bitter. Chlorhexidine concentration in mouthwashes till 0.12% and mucosa exposure not exceeding 60" twice a day, seem the best procedure to protect tastes in clinical practice.

Adult↗
PubMed2002

Postnatal development of membrane excitability in taste cells of the mouse vallate papilla.

The mammalian peripheral taste system undergoes functional changes during postnatal development. These changes could reflect age-dependent alterations in the membrane properties of taste cells, which use a vast array of ion channels for transduction mechanisms. Yet, scarce information is available on the membrane events in developing taste cells. We have addressed this issue by studying voltage-dependent Na+, K+, and Cl- currents (I(Na), I(K), and I(Cl), respectively) in a subset of taste cells (the so-called "Na/OUT" cells, which are electrically excitable and thought to be sensory) from mouse vallate papilla. Voltage-dependent currents play a key role during taste transduction, especially in the generation of action potentials. Patch-clamp recordings revealed that I(Na), I(K), and I(Cl) were expressed early in postnatal development. However, only I(K) and I(Cl) densities increased significantly in developing Na/OUT cells. Consistent with the rise of I(K) density, we found that action potential waveform changed markedly, with an increased speed of repolarization that was accompanied by an enhanced capability of repetitive firing. In addition to membrane excitability changes in putative sensory cells, we observed a concomitant increase in the occurrence of glia-like taste cells (the so called "leaky" cells) among patched cells. Leaky cells are likely involved in dissipating the increase of extracellular K+ during action potential discharge in chemosensory cells. Thus, developing taste cells of the mouse vallate papilla undergo a significant electrophysiological maturation and diversification. These functional changes may have a profound impact on the transduction capabilities of taste buds during development.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed2003

Quantitative assessment of gustatory function in a clinical context using impregnated "taste strips".

Assessment of gustatory sensitivity in a clinical setting is the prerequisite for correct diagnosis and adequate treatment of taste dysfunction. Despite of this, no taste test has been established for the routine clinical testing. The aim of the present study was to create a protocol which is easy to administer. The presently used technique is based on strips made from filter paper which were impregnated with different taste solutions (four concentrations each for sweet, sour, salty and bitter). These strips are placed on the tongue and subjects are asked to identify the taste quality. After establishing the concentration range of the taste solutions, the test was tried in 69 subjects. Each subject received eighteen taste strips (four concentrations of each taste quality plus two blanks) in a pseudo-randomized sequence. Results from this new procedure correlated significantly with the results of the well established extensive three-drop-technique (r69 = 0.67). Repeated measures indicated good reproducibility of the results for the taste strips (r69 = 0.68). These data suggest the usefulness of this new technique in routine clinical practice. Major advantages are long shelf-life, convenience of administration, short time needed for testing (approximately 8 min), and the possibility to test each side of the tongue separately.

Adolescent↗
PubMed2004

Taste and odour testing: how valuable is training?

Correct identification of specific tastes and odours in a water supply can be a powerful tool in identifying the cause of the problem and facilitating rapid remediation. While taste and odour identification can be achieved by laboratory testing, consumer involvement is not only worthwhile as a public education exercise but can also indicate tastes and odours to which the public do not object. Interpretation of taste and odour results is a complex process. The Australian Water Quality Centre (AWQC), based in Adelaide, South Australia, has established a flavour profile panel, trained in Flavour Profile Analysis (FPA). This group was chosen to carry out a survey of tastes and odours present in selected Australian water supplies and laboratory treated water and bottled water. The waters were also assessed by a group of untrained volunteers to simulate the responses of consumers. In two series of tests there were significant differences in responses between the groups with respect to the intensity of the tastes and odours detected. In both instances the responses by the trained group were more consistent, making interpretation of results more straightforward. In the second series of tests the panellists were also asked their personal preferences. The results showed in general the preferred waters were those with minimal taste and odour and this was generally irrespective of the type of taste and odour present.

Australia↗
PubMed1990

Convergence in mammalian nucleus of solitary tract during development and functional differentiation of salt taste circuits.

To determine the type and extent of neural rearrangements that are made during functional differentiation of circuits for salt taste processing, we determined receptive field size and salt response characteristics of second-order taste cells in 3 age groups of sheep. Neurophysiological recordings were made from single cells in the nucleus of the solitary tract (NST) in fetal, perinatal, and postnatal sheep. Responses to NH4Cl, NaCl, and KCl were measured, and location and number of fungiform papillae in the receptive field were determined by stimulating individual papillae with anodal electrical current. The data are compared with previous, parallel measures from chorda tympani nerve afferent taste fibers to permit conclusions about convergence or divergence onto second-order cells. Receptive field size of second-order taste neurons increases during development, in contrast to the decrease in field size observed previously for chorda tympani nerve fibers during the same period. Furthermore, receptive fields of second-order cells are significantly larger than those of first-order fibers at perinatal and lamb ages, but not fetal. Thus, there is convergence of first-order taste afferents onto brain-stem neurons, and the convergence increases remarkably between fetal and perinatal periods. Associated with the increase in convergence are increased salt response frequencies relative to afferent fibers for NaCl in perinatal animals and lambs, and for KCl in lambs. The increase in frequencies occurs before NST neurons are functionally mature, as indicated by the rapid response adaptation of many cells in young animals. Convergence in NST during development apparently functions to maximize gain for processing neural responses to NaCl. In the periphery, response frequencies to NaCl are very low in fetuses, and increase progressively during development. In the NST, NaCl response frequencies are high even in fetuses, and remain high. The process of convergence onto second-order cells is accomplished with maintenance of order in afferent projections because receptive fields of NST neurons are composed of fungiform papillae that are clustered together, not dispersed over the tongue. Our quantification of taste receptive field size at 2 neural levels provides strong evidence for increasing convergence in the NST during development. Altering patterns of afferent neural input and geometry of second-order neurons may have a role in establishing convergence. The convergence has an apparently special function: to increase gain for NaCl taste sensation. Therefore, neural rearrangements during differentiation of salt taste pathways result in specific functional outcomes.

Ammonium Chloride↗
PubMed1989

[Taste disorders and associated factors in type 1 diabetes].

In order to study taste in type 1 diabetes (insulin-dependent), 57 consecutive diabetic patients (mean duration of diabetes +/- SEM = 11.4 +/- 0.4 years) and 38 control subjects underwent electrogustometry and chemical gustometry. The diabetic and control group were comparable with the exception of the ponderal index which was significantly higher in diabetics (p less than 0.05). A deterioration in taste appreciation was confirmed in the diabetic group compared to the control group on electrogustometry (mean threshold: 184.3 +/- 15.8 vs 58.7 +/- 9.2 mu A; p less than 0.001) and chemical gustometry (mean score: 13.2 +/- 0.7 vs 17.1 +/- 0.8; p less than 0.001). Electrical hypogueusia was found in 73% of the diabetics compared to 16% of controls (p less than 0.001). The 4 primary tastes were involved in the deterioration. Multivariate analysis associated the taste disorder with the diabetic status of the subjects, their alcohol and tobacco consumption. In the diabetic group the deterioration in taste was associated with the complications and duration of diabetes. On multivariate analysis peripheral neuropathy had the strongest association with taste disorders. These results suggest that deterioration in taste occurs during the progression of type 1 diabetes and that the taste disorder could be a degenerative complication of the disease. A neuropathic type mechanism could be involved.

Adult↗
PubMed1989

[Localization and gustatory responsiveness of cortical taste area in the hamster].

Mapping of evoked potentials on the cortical surface following electrical stimulation of the chorda tympani and the glossopharyngeal nerve, and anodal D.C. stimulation of the tongue indicated that the cortical taste area (CTA) was located in the dysgranular insular cortex just dorsal to the rhinal fissure near the middle cerebral artery in the hamster. Bilateral lesion of the CTA attenuated or disrupted the conditioned taste aversion that had been acquired preoperatively. This fact suggests that the CTA plays a role in some cognitive processes of taste. Experiments using anterograde and retrograde axonal transport of wheat-germ agglutinin conjugated horseradish peroxidase showed that the CTA received inputs from the contralateral CTA, amygdala, thalamic taste area and the pontine taste area, and that neurons in the CTA (chiefly in layer V) sent axons to the contralateral CTA, amygdala, and the thalamic, pontine and bulbar taste areas. Responses of 87 CTA neurons to the four basic taste stimuli were recorded in urethane-anesthetized hamsters. Majority of the CTA neurons (85%) existed in the dysgranular insular cortex. Neurons responding best to sucrose tended to be located rostrally, those to NaCl caudally, and those to HCl were distributed evenly in the CTA. Judging from the breadth of responses to the four tastes and across-neuron correlation coefficients, responsiveness of neurons in layer V is more narrowly tuned than in layers II-IV and VI.

Animals↗
PubMed1985

Tastes associated with parenteral chemotherapy for breast cancer.

We employed a structured interview to retrospectively study tastes and vomiting associated with the parenteral components of cyclophosphamide, methotrexate, and 5-FU in 45 patients with stage II-IV breast cancer. Sixteen patients (36%) reported tastes which generally occurred in each cycle within 30 minutes of parenteral drug administration, lasted less than or equal to 1 hour, and were bitter. Five patients recalled that tastes seemed to produce vomiting. Tasting was significantly associated with postchemotherapy (P less than 0.01) but not anticipatory vomiting. Employing logistic regression techniques, tasting did not significantly improve prediction of anticipatory vomiting by postchemotherapy vomiting. Tastes may be produced by the action of plasma or salivary cyclophosphamide, methotrexate, and 5-FU on taste buds. While tastes might cause some vomiting, they are not necessary for it. Because this was a retrospective study with a small sample, these findings require confirmation.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1982

Taste bud adenosine -3'5'-monophosphate phosphodiesterase: activity, subcellular distribution and kinetic parameters.

Higher activity of cyclic adenosine 3',5'-monophosphate (cAMP) phosphodiesterase (PDE) was found in homogenates from bovine circumvellate papillae bearing taste buds compared to activity in homogenates from areas surrounding these papillae in which no taste buds were present. With progressive purification of these homogenates cAMP PDE activity increased in the taste bud enriched fractions relative to that measured in the non-taste bud bearing epithelial tissue. The highest levels of cAMP PDE activity were measured in those taste bud fractions in which purification was greatest. Kinetic studies in both taste bud derived and control tissues showed two apparent Km values, one relatively high, the other, lower. cAMP PDE activity of taste bud membranes was enhanced by Mg++, Mn++ and imidazole and inhibited by ethylene-bis (beta-aminoethylether) N,N-tetra-acetic acid (EGTA), isobutyl methyl xanthine (IBMX), theophylline, and cyclic guanosine 3',5'-monophosphate (cGMP). The possible role for cAMP PDE in taste function is discussed.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1993

Keratin expression in taste bud cells of the circumvallate and foliate papillae of adult mice.

The patterns of keratin expression of taste buds in murine oral mucosa were examined using a panel of antibodies with various specificities for cytokeratins. The patterns for taste buds differed markedly from those of the surrounding epithelium but no regional differences in the staining patterns of the taste buds themselves were detected. The taste buds and the ducts of von Ebner's glands were strongly stained by monoclonal antibodies (mAbs) against cytokeratins (K) 8, 18 and 19, those typically expressed by simple epithelia. Merkel cells, which are also present in the oral epithelium and may correspond to the type III cells in taste buds, stained for K8 and K18 but not K19. None of the mAbs against simple epithelial keratins stained the stratifying epithelium of the trench wall or of the oral mucosa. Antibodies with specificity for keratins that are expressed as differentiation products of the mucosal epithelium did not stain taste buds. The staining pattern of the epithelium of the trench wall indicated that it expressed some keratins typical of stratifying epithelia but lacked the full pattern of differentiation of the adjacent mucosal epithelia. Staining within the taste buds was not homogeneous but no clear differences of keratin staining could be directly related to the subtypes of cells constituting them. The markedly differing patterns of keratin expression between taste buds and the adjacent epithelium raises questions about the type of inductive signals that produce and maintain these patterns.

Animals↗
PubMed1995

The effects of anorectic and aversive agents on deprivation-induced feeding and taste aversion conditioning in rats.

We compared the effects of intraperitoneally administered LiCl (0.5-2830 mumol/kg), sulfated cholecystokinin26-33 (10-1000 nmol/kg; CCK-8), nonsulfated CCK-8 (500 and 1000 nmol/kg), sulfated CCK26-29 (500 and 1000 nmol/kg), CCK30-33 (10-1000 nmol/kg) bombesin (10-1000 nmol/kg; BOM), (dl) fenfluramine HCl (0.9-37.3 mumol/kg; fenfluramine), fluoxetine HCl (2.9-86.7 mumol/kg; fluoxetine), and d-amphetamine sulfate (0.27-10.9 mumol/kg; AMPH) on both 18-hr deprivation-induced feeding and one-bottle, taste aversion conditioning in male, Long-Evans rats. Doses of LiCl > or = 177 mumol/kg (or 7.5 mg/kg) induced significant, dose-related taste aversions, but only doses of LiCl > or = 2123 mumol/kg (90 and 120 mg/kg) induced significant anorexia. CCK-8 induced marked anorexia (at doses > or = 25-50 nmol/kg), but only relatively mild taste aversions which were only statistically significant at the highest dose (1000 nmol/kg). The anorectic effects of CCK-8 at 500 and 1000 nmol/kg, but not at lower doses, lasted at least 3 hr. Sulfated CCK26-29, CCK30-33 and nonsulfated CCK-8 induced neither anorexia nor taste aversion. BOM induced marked anorexia at all doses tested, but did not induce statistically significant taste aversions. The nonpeptidal anorectic compounds, fenfluramine, fluoxetine, and AMPH, induced both dose-related anorexia and taste aversion conditioning. We focus on several issues concerning the interpretation of taste aversion conditioning. Our results challenge any simple relationship between the ability of a compound to induce taste aversion and to decrease feeding.

Animals↗
PubMed1993

[Enteral nutrition and changes in taste in diabetic patients: a double-blind prospective study].

The authors present a prospective double blind test aimed at objectively determining the acceptance of flavoured orally administered enteric diets specific to patients with glucose metabolism alterations (Glucerna and Precitene Diabet), in the light of the taste disorders described in such patients. Sixty-two patients were studied, 32 diabetics and 32 control patients, who were given a sample of each product; the level of acceptance was quantified on a modified wine-tasting scale. The average taste of the diabetics was 12.1 points (SD = 4.34) for Glucerna, and 10.1 (SD = 3.91) for the Precitene Diabet. In the control patients, the scores were 12.7 (SD = 3.78) and 13.2 (SD = 3.23) respectively. Multiple regression analysis did not reveal significant differences in taste according to age, sex or place of origin. Average taste among the diabetic patients as a whole with both products was 11.2 points and, for the nondiabetics, 12.92. The model detected significant differences (p = 0.01) between the two groups. The average taste of the diabetics was less than that of the non-diabetics, irrespective of all the remaining variables examined, including the type of preparation. These results confirm the lower oral acceptance in diabetic patients, possibly associated with disorders in the sense of taste, showing the utility of the modified wine-tasting scale as a test in evaluating the acceptance of enteric diets which must be administered orally.

Adolescent↗
PubMed1977

Mutual action of taste and olfaction.

Subjects estimated the intensity of various concentrations of an odorant (ethyl butyrate), a tastant (sodium saccharin), and mixtures of the two. The question of primary interest was whether the perceived intensity of the odor-tast mixtures would be equal to, greater than , or less than the intensities of the unmixed components. The outcome approximated simple additivity: The intensity of the mixtures was only slightly less than the sum of the perceived intensities of the unmixed components. An examination of how subjects apportioned their judgments into the categories odor and taste revealed the existence of taste-smell confusions. Subjects ascribed little odor magnitude to solutions containing only sodium saccharin, but ascribed considerable taste magnitude to solutions containing only ethyl butyrate. The taste ascribed to ethyl butyrate was not due exclusively to its action on gustation since, when the nostrils were closed, as much as 80% of the "taste" disappeared. Subjects seem to resolve ambiguity regarding the locus of mutual olfactory-taste stimulation in favor of taste.

Butyrates↗
PubMed1997

NMDA receptor and the tyrosine phosphorylation of its 2B subunit in taste learning in the rat insular cortex.

We demonstrate that the NMDA receptor is involved in taste learning in the insular cortex of the behaving rat and describe two facets of this involvement. Blockage of the NMDA receptor in the insular cortex by the reversible antagonist APV during training in a conditioned taste aversion (CTA) paradigm impaired CTA memory, whereas blockage of the NMDA receptor in an adjacent cortex or before a retrieval test had no effect. When rats sampled an unfamiliar taste and hence learned about it, either incidentally or in the context of CTA training, the tyrosine phosphorylation of the NMDA receptor subunit 2B (NR2B) in the insular cortex was specifically increased. The level of tyrosine phosphorylation on NR2B was a function of the novelty of the taste stimulus and the quantity of the taste substance consumed, properties that also determined the efficacy of the taste stimulus as a conditioned stimulus in CTA; however, blockage of the NMDA receptor by APV during training did not prevent tyrosine phosphorylation of NR2B. We suggest that tyrosine phosphorylation of NR2B subserves encoding of saliency in the insular cortex during the first hours after an unfamiliar taste is sampled and that this encoding is independent of another, necessary role of NMDA receptors in triggering experience-dependent modifications in the insular cortex during taste learning. Because a substantial fraction of the NR2B protein in the insular cortex seems to be expressed in interneurons, saliency and the tyrosine phosphorylation of NR2B correlated with it may modulate inhibition in cortex.

Animals↗
PubMed1998

Uptake and release of neurotransmitter candidates, [3H]serotonin, [3H]glutamate, and [3H]gamma-aminobutyric acid, in taste buds of the mudpuppy, Necturus maculosus.

Neurotransmitters in vertebrate taste buds have not yet been identified with confidence. Serotonin, glutamate, and gamma-aminobutyric acid (GABA) have been postulated, but the evidence is incomplete. We undertook an autoradiographic study of [3H]serotonin, [3H]glutamate, and [3H]GABA uptake in lingual epithelium from the amphibian, Necturus maculosus, to determine whether taste bud cells would accumulate and release these substances. Lingual epithelium containing taste buds was incubated in low concentrations (0.4-6 microM) of these tritiated transmitter candidates and the tissue was processed for light microscopic autoradiography. Merkel-like basal taste cells accumulated [3H]serotonin. When the tissue was treated with 40 mM K+ after incubating the tissue in [3H]serotonin, cells released the radiolabelled transmitter. Furthermore, depolarization (KCl)-induced release of [3H]serotonin was Ca-dependent: if Ca2+ was reduced to 0.4 mM and 20 mM Mg2+ added to the high K+ bathing solution, Merkel-like basal cells did not release [3H]serotonin. In contrast, [3H]glutamate was taken up by several cell types, including non-sensory epithelial cells, Schwann cells, and some taste bud cells. [3H]glutamate was not released by depolarizing the tissue with 40 mM K+. [3H]GABA uptake was also widespread, but did not occur in taste bud cells. [3H]GABA accumulated in non-sensory epithelial cells and Schwann cells. These data support the hypothesis that serotonin is a neurotransmitter or neuromodulator released by Merkel-like basal cells in Necturus taste buds. The data do not support (nor rule out) a neurotransmitter role for glutamate or GABA in taste buds.

Animals↗
PubMed1998

Electrophysiological characterization of a putative supporting cell isolated from the frog taste disk.

Chemosensory cells in vertebrate taste organs have two obvious specializations: an apical membrane with access to the tastants occurring in food, and synapses with sensory axons. In many species, however, certain differentiated taste cells have access to the tastants but lack any synaptic contacts with axons, and a supportive rather than chemosensory function has been attributed to them. Until now, no functional data are available for these taste cells. To begin to understand their role in taste organ physiology, we have characterized with patch-clamp recording techniques the electrophysiological properties of a putative supporting cell-the so-called wing cell-isolated from frog taste disks. Wing cells were distinguished from chemosensory elements by the presence of a typical, sheet-like apical process. Their resting potential was approximately -52 mV, and the average input resistance was 4.8 GOmega. Wing cells possessed voltage-gated Na+ currents sensitive to TTX, and an inactivating, voltage-gated K+ current sensitive to TEA. Current injections elicited single action potentials but not repetitive firing. We found no evidence for voltage-gated Ca2+ currents under various experimental conditions. Amiloride-sensitive Na+ channels, thought to be involved in Na+ chemotransduction, were present in wing cells. Many of the membrane properties of wing cells have been also reported for chemosensory taste cells. The presence of ion channels in wing cells might be suggestive of a role in controlling the microenvironment inside the taste organs or the functioning of chemosensory cells or both. In addition, they might participate directly in the sensory transduction events by allowing loop currents to flow inside the taste organs during chemostimulation.

Action Potentials↗
PubMed1991

Responses of neurons in the primate taste cortex to glutamate.

In order to investigate the neural encoding of glutamate in the primate, recordings were made from 190 taste responsive neurons in the primary taste cortex and adjoining orbitofrontal cortex taste area in macaques. Single neurons were found that were tuned to respond best to glutamate (umami taste), just as other cells were found with best responses to glucose (sweet), sodium chloride (salty), HCl (sour), and quinine HCl (bitter). Across the population of neurons, the responsiveness to glutamate was poorly correlated with the responsiveness to NaCl, so that the representation of glutamate was clearly different from that of NaCl. Further, the representation of glutamate was shown to be approximately as different from each of the other four tastants as they are from each other, as shown by multidimensional scaling and cluster analysis. Moreover, it was found that glutamate is approximately as well represented in terms of mean evoked neural activity and the number of cells with best responses to it as the other four stimuli, glucose, NaCl, HCl and quinine. It is concluded that in primate taste cortical areas, glutamate, which produces umami taste in humans, is approximately as well represented as are the tastes produced by: glucose (sweet), NaCl (salty), HCl (sour) and quinine HCl (sour).

Animals↗