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PubMed2005

Increased taste intensity perception exhibited by patients with chronic back pain.

There is overlap between brain regions involved in taste and pain perception, and cortical injuries may lead to increases as well as decreases in sensitivity to taste. Recently it was shown that chronic back pain (CBP) is associated with a specific pattern of brain atrophy. Since CBP is characterized by increased sensitivity to pain, we reasoned that the sense of taste might also be enhanced in CBP. Detection and recognition thresholds were established for a sour taste and ratings of both suprathreshold taste intensity and pleasantness-unpleasantness perception were collected for sweet, sour, salty and bitter stimuli in 11 CBP patients and 11 matched control subjects. As a control, ratings were also collected for visual assessment of degree of grayness. There was no difference between CBP and control subjects for visual grayness rating. On the other hand, CBP patients in comparison to control subjects rated gustatory stimuli as significantly more intense but no more or less pleasant and showed a trend towards a lower detection threshold (i.e. increased sensitivity). The selectivity of the taste disturbance suggests interaction between pain and taste at specific brain sites and provides further evidence that CBP involves specific brain abnormalities.

Adult↗
PubMed1975

[Relations between structure and bitter taste of amino acids and peptides. I. Amino acids and related compounds].

About 60 amino acids, amino acid esters, N-acyl amino acids, amines, and other related compounds were tested for bitter taste. The recognition thresholds are in the range from 100 muMol/ml (L-2-amino butyric acid) to 0.8 muMol/ml (benzamide). Essential structural requirements for bitter compounds are a polar (electrophilic) group and a hydrophobic one, which must be arranged in a defined manner. The results are summarized in a model which shows the zones of contact between bitter compound and receptor.

Amino Acids↗
PubMed1990

Experimental sodium depletion and salt taste in normal human volunteers.

To examine the sensory effects of extreme sodium depletion in humans, 10 normal volunteers were fed a very-low-sodium diet and were treated with diuretics for 10 d. Urine samples were collected and blood was drawn for hormone analyses. Taste tests included threshold and intensity judgments of salt (NaCl) and sucrose and preferences for salt and sucrose in foods. Subjects also rated the pleasantness of 29 foods listed on a questionnaire. Substantial sodium depletion was induced in all subjects. Salt thresholds decreased in a majority of the subjects whereas preference judgments for salt in foods tended to be greater during the depletion period. The changes in pleasantness of the 29 foods revealed that saltier foods were substantially more attractive during the depletion period than during the pre- and postdepletion periods. These data indicate that experimental sodium depletion in humans is followed by moderate sensory changes and an increased preference for salty foods.

Adult↗
PubMed1993

Changes in taste and flavor in aging.

This study aims at understanding the role of mixtures (mutual quality suppression) in the evaluation of impact of the human aging process on the perception of taste. Heretofore, the effect of aging on taste has been directed at threshold and suprathreshold magnitudes of single chemicals (e.g., NaCl, sucrose, citric acid) in aqueous solution. Although absolute thresholds typically rise in advanced age (2 to 9 times, depending on the study), suprathreshold magnitude assessed by magnitude matching seems (except for bitter) to resist change in the way presbycusis spares suprathreshold loudness, fostering the impression that aging may handicap the aged little in the perception of food. Asked, however, to discriminate the presence-absence of the prescribed salt flavoring (nominally suprathreshold) in tomato soup, the young outperformed the middle-aged who, in turn, outperformed the elderly. Moreover, NaCl thresholds in the presence of tomato measured several times higher than in water, but the difference between the young and the elderly continued to hold. Elevation of threshold to much higher levels by mixture suppression leaves the young-elderly difference unchanged, implying that the elderly may fail to detect salt levels that really count in their diet. To examine the relation between age and taste mixtures, we measured detection thresholds: (1) for NaCl in citric acid, from zero to strong; (2) for sucrose in citric acid, from zero to strong; and (3) for citric acid in sucrose, from zero to strong. Whether in water alone or in a weak or strong suppressor, the elderly subjects' threshold was consistently 2 or 3 times higher than that of the young. Moreover, the way in which threshold for one quality rises with concentration of a suppressor is the same, except for constant upward displacement of the elderly peoples' threshold. In general, both young and elderly confuse salty and sour (show large suppression at all concentrations of the suppressor) much more than they confuse sweet and sour (seen mainly at high concentrations of the suppressor). Study of other mixtures is planned.

Adult↗
PubMed1992

Convergence of oral and extraoral information in the superior secondary gustatory nucleus of the channel catfish.

Neurons within the superior secondary gustatory nucleus (nGS) of the channel catfish were examined electrophysiologically for responses to mechanical and chemical stimulation of neural peripheral receptive fields (RFs). Of the 28 single units sampled, 18 had mechanosensory RFs on the extraoral epithelium, two had RFs within the oropharyngeal cavity, and eight had RFs that included both oral and extraoral surfaces. RF sizes varied from approximately 2 cm2 on the ipsilateral lips and barbels to the whole body surface, bilaterally. No obvious correlation existed between RF pattern and recording location within the nGS. Eight of the mechanosensory nGS units also responded to amino acid taste stimuli with thresholds from micromolar to millimolar concentrations. The convergence of oral and extraoral information within the nGS determined electrophysiologically was corroborated anatomically by HRP labeling experiments. Restricted HRP injections into each of the primary gustatory nuclei of the medulla, the vagal (VL) and facial (FL) lobes, labeled fibers that appeared to terminate diffusely throughout the nGS, and injections into different portions of the nGS retrogradely labeled cells in both the FL and VL. The present electrophysiological and neuroanatomical data distinguish the convergent gustatory representation within the nGS of the catfish from the highly specific somatotopic and viscerotopic sensory maps previously identified in the FL and VL, respectively.

Afferent Pathways↗
PubMed1989

[The function of the taste analyzer in patients with disseminated sclerosis].

The absolute threshold of gustatory sensibility was studied in 100 patients with multiple sclerosis by means of applying gustatory irritants by the drop method. The patients showed an elevation of the threshold of gustatory sensation as compared with the healthy concerning sweet, salty, bitter. In 5 patients unstable loss loss of taste was the first symptom of the disease.

Adult↗
PubMed2006

Effects of GPD1 overexpression in Saccharomyces cerevisiae commercial wine yeast strains lacking ALD6 genes.

The utilization of Saccharomyces cerevisiae strains overproducing glycerol and with a reduced ethanol yield is a potentially valuable strategy for producing wine with decreased ethanol content. However, glycerol overproduction is accompanied by acetate accumulation. In this study, we evaluated the effects of the overexpression of GPD1, coding for glycerol-3-phosphate dehydrogenase, in three commercial wine yeast strains in which the two copies of ALD6 encoding the NADP+-dependent Mg2+-activated cytosolic acetaldehyde dehydrogenase have been deleted. Under wine fermentation conditions, the engineered industrial strains exhibit fermentation performance and growth properties similar to those of the wild type. Acetate was produced at concentrations similar to that of the wild-type strains, whereas sugar was efficiently diverted to glycerol. The ethanol yield of the GPD1 ald6 industrial strains was 15 to 20% lower than that in the controls. However, these strains accumulated acetoin at considerable levels due to inefficient reduction to 2,3-butanediol. Due to the low taste and odor thresholds of acetoin and its negative sensorial impact on wine, novel engineering strategies will be required for a proper adjustment of the metabolites at the acetaldehyde branch point.

Acetates↗
PubMed1987

Comparative modes of action of lactitol and lactulose in the treatment of hepatic encephalopathy.

Lactitol, an unabsorbed sugar with defined laxative threshold and superior taste properties has been suggested as an alternative to lactulose in the treatment of hepatic encephalopathy. In the present study we have compared the colonic metabolism of the two sugars using an in vitro faecal incubation system. Both sugars were readily metabolised by faecal bacteria producing volatile fatty acids and the metabolism was inhibited by neomycin. The effect of lactitol and lactulose on terminal ileal and colonic pH was monitored in six normal subjects using a radiotelemetry technique. Both sugars significantly lowered right colonic pH (basal -6.51 +/- 0.48 vs lactitol -5.63 +/- 0.50; lactulose -5.18 +/- 0.82, p less than 0.05). The pH of rest of the colon and terminal ileum was unaffected. Neomycin given concurrently with lactulose abolished acidification of right colon. As lactitol and lactulose have similar effects within the colon, lactitol would appear to have a role in the treatment of hepatic encephalopathy. As neomycin antagonises the effect of lactulose in the colon, its concurrent use may be less effective in the treatment of hepatic encephalopathy.

Colon↗
PubMed1979

[Taste test].

Explore the source record for details and available documents.

Differential Threshold↗
PubMed1997

Effect of food palatability on early (cephalic) phase of diet-induced thermogenesis in nonobese and obese man.

OBJECTIVE: To study the effect on the early (cephalic) phase of diet-induced thermogenesis (EDT) of palatable vs unpalatable food, in nonobese and obese man. SUBJECTS: Twenty-four nonobese volunteers and 19 obese clinic patients. DESIGN AND MEASUREMENTS: A palatable, liquid formula meal of Ensure (1048 KJ, 450 ml), and of Ensure made unpalatable by addition of aqueous KCl, were sipped on nonconsecutive mornings. O2 consumption (ml/min) was measured before, and starting 30, 60 and 90 min after beginning the test meal, from which EDT was calculated as KJ/min. RESULTS: Palatability of the test meal significantly increased EDT (palatability effect, P = 0.004) but obesity status per se, did not affect EDT. Nevertheless, the effect of palatability on EDT was dependent on obesity status, being seen only in the nonobese. EDT was significantly greater in the nonobese after the palatable than the unpalatable meal: (mean +/- s.e.m.) 2.45 +/- 0.14 vs 1.83 +/- 0.14; P < 0.0001, but not in the obese: 1.93 +/- 0.28 vs 1.73 +/- 0.20; P < 0.21. Therefore only after the palatable meal was EDT less in the obese compared with the nonobese: P < 0.05. The threshold for the unpleasant taste of added KCI was 31% higher in the obese than the nonobese: 4.2 +/- 0.4 vs 3.2 +/- 0.2 [g KCI]; P < 0.025. CONCLUSIONS: The early (cephalic) phase of dietary thermogenesis (EDT) is significantly increased in the nonobese by palatability, but not in the obese, so that only after a palatable meal is EDT less, or 'deficient,' in the obese compared with the nonobese. Also, the obese have a higher threshold for the unpleasant taste of KCI (in Ensure) than the nonobese.

Adolescent↗
PubMed1994

PTC/PROP tasting: anatomy, psychophysics, and sex effects.

Taste worlds of humans vary because of taste blindness to phenylthiocarbamide (PTC) and its chemical relative, 6-n-propylthiouracil (PROP). We review early PTC studies and apply modern statistical analyses to show that a higher frequency of women tasted PTC crystals, and were tasters (threshold classification). In our laboratory, scaling of PROP bitterness led to the identification of a subset of tasters (supertasters) who rate PROP as intensely bitter. Supertasters also perceive stronger tastes from a variety of bitter and sweet substances, and perceive more burn from oral irritants (alcohol and capsaicin). The density of taste receptors on the anterior tongue (fungiform papillae, taste buds) correlate significantly with perceived bitterness of PROP and support the supertaster concept. Psychophysical data from studies in our laboratory also show a sex effect; women are supertasters more frequently. The anatomical data also support the sex difference; women have more fungiform papillae and more taste buds. Future investigations of PTC/PROP tasting and food behaviors should include scaling to identify supertasters and separate sex effects.

Female↗
PubMedDate not supplied

Taste perception of bitter compounds in young and elderly persons: relation to lipophilicity of bitter compounds.

Threshold and suprathreshold sensitivities to 13 bitter compounds were determined for 16 young adults (mean age = 27.4 years) and 18 elderly persons (mean age = 81.3 years). Half of the subjects in each age group were tasters of the bitter compound phenylthiocarbamide (PTC) and half were nontasters. Both detection and recognition thresholds, determined by a forced-choice ascending detection method, were elevated in older subjects; there were no significant differences in threshold values between tasters and nontasters of PTC. A strong relationship between bitter threshold values and the logarithm of the octanol/water partition coefficient was found for both young and elderly subjects. For young subjects, suprathreshold bitterness ratings were more intense for tasters of PTC compared with nontasters. Significant losses in suprathreshold sensitivity to bitter tastants with age were also found. However, unlike threshold sensitivity, no relationship was found between suprathreshold bitter taste intensity and lipophilicity.

Adult↗
PubMed1998

A multimodal assessment of sensory thresholds in aging.

Young and elderly subjects yielded forced-choice detection thresholds in each of seven sensory tasks: (1) taste of sodium chloride, (2) smell of butanol, (3) cooling, (4) low-frequency vibrotaction, (5) high-frequency vibrotaction, (6) low-frequency hearing, and (7) high-frequency hearing. Average scores across these tasks nearly perfectly separated the 22 elderly from the 15 young subjects. For individual modalities, however, separation between the groups varied from complete (high-frequency touch) to negligible (low-frequency hearing). Scores on the Boston Picture Naming Test and especially the Wechsler Logical Memory Test correlated strongly with average threshold score (Pearson r = .80) and moderately with scores on individual modalities. This sensory-cognitive link is not caused, as might be supposed, by diminishing age-related capacity to handle the detection task, because the very same task resulted in negligible age effect (low-frequency hearing) and large effect (high-frequency hearing) in the same subjects.

Adolescent↗
PubMed2002

A new whole-mouth gustatory test procedure. 1. Thresholds and principal components analysis in healthy men and women.

Gustatory testing using the whole-mouth method was performed in 123 healthy young male and female subjects. The average thresholds for detection and recognition of the four basic tastes were not greatly different from the normal thresholds previously reported in Japan: a 0.0165 M solution of sucrose for sweet taste, a 0.0316 M solution of table salt for salty taste, a 0.000743 M solution of tartaric acid for sour taste and a 0.0000203 M solution of quinine hydrochloride for bitter taste. These results indicate that the whole-mouth gustatory test procedure employed in this study may be useful for evaluating gustatory function clinically. Principal components analysis confirmed that sweet, salty, sour and bitter are indeed the four basic tastes and revealed that the sensation of taste is detected before the specific taste is recognized, regardless of the specific taste tested.

Adolescent↗
PubMed2003

[Taste disorders and recovery of the taste function after middle ear surgery].

BACKGROUND: The incidence and the scale of recovery of the taste function after middle ear surgery is usually determined by the use of anamnestic data and electrogustometry. METHODS: Taste tests (regional chemical taste test, electrogustometry and subjective evaluation) were performed preoperatively, 2 to 3 weeks and 6 to 9 months after middle ear surgery. These results were evaluated by taking the scale of chorda tympani nerve (CTN) manipulation into consideration. Three groups were chosen: group 1: no or small CTN manipulation, n = 54; group 2: strong CTN manipulation, n = 14; group 3: severed CTN, n = 50. PATIENTS: In a prospective study 118 patients were examined after middle ear surgery in the ENT-Department of the University of Rostock between 2001 and 2002. 61 females and 57 males, age from 7 - 81 years, were included. RESULTS: Complaints were observed in all three groups, mainly in groups 2 and 3. These included taste disorders, taste phenomenon and numbness of the tongue. Using regional chemical taste tests, the taste loss of group 3 could be proven for those patients with complaints in 64 % and for those patients without complaints in 27 %. The electrogustometry is more sensitive than chemical taste test. All patients had pathological thresholds after chorda cutting (78 % no thresholds; 22 % elevated thresholds). 68 out of 118 patients (58 %) had a second follow-up after 6 to 9 months after middle ear surgery. The complaints are declining in all groups. In groups 2 and 3 a recovery of taste function could be observed. Even if the number of patients with severed chorda, who suffer from taste disorders, diminishes, a recovery of the taste function could only be observed in 30 %. CONCLUSIONS: The scale of chorda manipulation is important for the recovery of the taste function after middle ear surgery. The CTN should be preserved intraoperatively, especially when an operation of the contralateral ear is planned as well.

Adolescent↗
PubMed1994

Bitter taste in aging: compound-specific decline in sensitivity.

Threshold sensitivity to and the perceived intensity of two bitter compounds, quinine sulfate and urea, were assessed in 52 young adults and 60 elderly adults. Consistent with previous literature, age-related declines in sensitivity to the bitterness of quinine were observed at both threshold and suprathreshold levels. In contrast, the same young and elderly subjects showed comparable sensitivity to the bitterness of urea. These results provide further support for the existence of multiple bitter taste transduction sequences in humans, and indicate that they may be differentially affected by aging.

Adolescent↗
PubMed1975

Taste rejection of nonnutritive sweeteners in cats.

Cats reject saccharin and cyclamate and are indifferent to dulcin, although they, like other mammals, prefer sucrose. The rejection threshold for saccharin found in this experiments, .0001 M, is about 2 log steps lower than a previously reported rejection threshold for sodium saccharin. Water produces a taste in cats adapted to their own saliva. The high sodium saccharin threshold may have resulted because the taste of the sodium saccharin was masked by the taste of the water solvent; however, saccharin may also be somewhat more aversive to the cat than sodium saccharin. Saccharin may produce an aversive taste because it stimulates receptor sites sensitive to substances bitter to man as well as those sensitive to sugars. In addition, saccharin may not be an effective stimulus for all sugar-sensitive sites.

Animals↗