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At least 973 records · Page 54Linked to original sources
PubMed1986

Taste preference for cough syrups: a comparative study of three codeine-containing medications.

Unpleasant taste is a common feature of cough syrups, particularly those containing codeine. An antitussive compound of codeine sulfate and chlorpheniramine maleate was formulated in a coated drug-resin complex, which prevents release of the active ingredients until they reach the stomach and small intestine. Thus patients do not taste the bitterness of the codeine. A three-way crossover taste test was conducted in 175 volunteers who tasted each of three cough syrups in random sequence, rated the taste of each, and ranked their preferences. The cough syrups used in the study were the aforementioned formulation (CM), promethazine hydrochloride with codeine (PH), and iodinated glycerol with codeine phosphate (IG). Tastes were rated on a scale from +2 (very good) to -2 (very poor). Mean rating scores for each product were 0.97 for CM, 0.14 for PH, and -1.5 for IG. Pairwise comparisons showed statistically significant differences between CM and PH (P less than 0.01) and CM and IG (P less than 0.001) but no significant difference between PH and IG. CM was ranked as most liked by 115 respondents and as least liked by 27 respondents. Reasons cited for this preference were its sweet rather than medicinal taste and its smooth, thick consistency. Bitterness was a common reason for the lack of preference for PH and IG. CM thus was shown to have greater user acceptability than either of the other two cough syrups tested.

Antitussive Agents↗
PubMed1979

Light and scanning microscopy of the taste organs and vascularization of the tongue of the spotted salamander, Salamandra salamandra (L.).

The mucosa of the spotted salamander tongue and its taste organs were investigated by means of light and scanning electron microscopy. The most striking feature of the salamander tongue is an almost complete lack of papillae which are replaced by long, radially disposed folds with linear arrays of taste organs along their ridges. In respect of morphology, the taste organs of the salamander occupy an intermediate position between the taste buds of Urodela and taste discs of Salientia. Scanning electron microscopic examination of microcorrosion casts of the blood vessels of the tongue has revealed that the structure of subepidermal capillary network reflects the topography of the tongue surface and the distribution of its taste organs. In the core regions of the folds the capillary loops accompanying gustatory receptors empty via their shorter, descending arms into the draining vessels, the initial segments of which retain a course parallel to that of the folds. In the few fungiform papillae the capillary vessels form single loops whose distal ends come to lie in the vicinity of taste discs.

Animals↗
PubMed1980

Quantitative analysis of developing epiglottal taste buds in sheep.

Epiglottal taste buds of the sheep increase in number during development, and continue to increase until the epiglottis has reached its adult size. However, since the increase in taste bud numbers is paralleled by increase in the surface area of the epiglottis, the density of taste buds decreases progressively in the fetus and newborn. After birth the density remains relatively constant. From examination of the morphological stages of epiglottal taste bud development, we conclude that taste buds are originally produced by de novo formation, but that further increase in numbers is effected by division of existing, developing taste buds. Because of the large number of taste buds, and the maintenance of their density on the epiglottis, it is concluded that they have an important functional role in upper airway protective reflexes.

Aging↗
PubMed1995

[Whole mouth gustatory test (Part 2)--Effect of aging, gender and smoking on the taste threshold].

The whole mouth test method was employed for examining changes in gustatory senses due to aging. Participants were 314 male and 356 female healthy volunteers not complaining of taste disorders. Simultaneously, the effects of smoking were examined, comparing 71 male smokers to 142 male non-smokers, ranging from 20 to more than 60 years of age. A multiple comparison procedure (Tukey-Kramer) was applied to age groups, revealing a significant increase in the threshold with age; high threshold values were observed in the "70s and older" group in comparison to the younger group for all tastes other than the sweet taste. Concerning the differences between males and females, the gustatory thresholds of males were found to be higher than those of females for some in the "20s and older" group and for all tastes other than the sweet taste, whereas the thresholds of males were lower than those of females for all taste qualities in the late teen group. As to male subjects in whom the effects of smoking could be studied, smokers in their 20s demonstrated a slight rise in the threshold only for the bitter taste.

Adolescent↗
PubMedDate not supplied

Reduced taste perception in AL amyloidosis. A frequently unnoticed sensory impairment.

BACKGROUND: Sporadic observations suggest a possible taste impairment in AL amyloidosis, but the frequency and intensity of this sensory anomaly are not known. MATERIALS AND METHODS: We submitted 21 AL amyloidotic patients, drawn from subjects referred to the Amyloidosis Study Center of the Department of Internal Medicine and Medical Therapy, University of Pavia, to suprathreshold scaling analysis. RESULTS: Taste acuity was reduced in most of them. Every taste showed independent behavior, and 90% of these patients were hypogeusic. True ageusia for one or two tastes was observed in 35% of patients. No patient was aware of reduced taste acuity. Macroglossia did not seem to play a prominent role in dulling tastes. CONCLUSIONS: Impairment of taste perception suggests that gustative neuropathy is a frequently unnoticed expression of sensory involvement in AL amyloidosis.

Adult↗
PubMed1995

Brain mechanisms of satiety and taste in macaques.

Flavor is the primary reinforcer of eating. As satiety is induced, the reinforcement of flavor is lost. Since flavor derives largely from taste, one might expect gustatory responsiveness to decline with increasing satiety. However, no such loss of sensitivity occurs in humans, even as the reinforcing value of taste declines with satiety. Thus, we explored the effect of satiety on taste responses at several levels of the macaque's nervous system to determine where is influence began. Taste-evoked activity in the NTS and primary taste cortex was unaffected by the induction of satiety through or administration of glucose. Taste cortex projects to amygdala and orbitofrontal cortex (OFC). In amygdala, satiety reduced responsiveness by 58%; in OFC, neurons were fully suppressed. Both amygdala and OFC project to the hypothalamus, where taste responsiveness was also suppressed. Thus, the neural impact of food is reduced not in area devoted to quality analysis, but in those concerned with motivation and reinforcement.

Administration, Oral↗
PubMed1995

Glycoconjugates and keratin 18 define subsets of taste cells.

Sections of neonatal, normal adult and denervated adult rat tongue were examined with lectin histochemistry. Attention was focused upon intragemmal cells (cells within the taste bud) and the surrounding perigemmal cells. Informative staining patterns were observed with four of 12 lectins: Ulex europaeus (UEA-I), Bauhinia purpurea (BPA), Helix pomatia (HPA) and Lotus tetragonolobus (LTA) agglutinins. In normal adult tongues, BPA bound to those lingual epithelial cells lacking contact with the basal lamina. After they formed, vallate taste buds were laterally surrounded by distinctive BPA-positive cells. HPA reacted selectively with 28% and LTA with 23% of the intragemmal cells in vallate/foliate taste buds. In double-stained taste buds there was a statistically significant overlap of LTA-positive cells and keratin 18-positive cells. The overlap between HPA binding and keratin 18 was more marked: double-stained cells comprized 67% of all stained cells. During taste bud development in neonates keratin 18 synthesis preceded HPA binding. In contrast, during the replacement of adult taste cells, keratin 18 synthesis and HPA binding were generally concurrent. Keratin 18 and HPA probably identify the same subset of older taste receptor cells. HPA may bind to glycoconjugates on the surface of keratin 18-positive cells. In denervated adult tongue the loss of all UEA-I-positive or BPA-positive perigemmal cells suggests that perigemmal as well as intragemmal cells are nerve-dependent.

Animals↗
PubMed1997

Taste: the neglected nutritional factor.

Scientists now think that every taste bud has some degree of sensitivity to all the primary taste sensations. The brain detects the type of taste by the ratio of stimulation of different taste buds. Many different substances have flavor-enhancing capacity, including ingredients that represent the primary tastes. Medications, chronic disorders, and radiation therapy can alter taste perception, resulting in loss of appetite. Individualizing nutrition advice, with consideration of taste, health needs, and personal preferences, is a "signature dish" of quality dietetics practice.

Aged↗
PubMed1991

Transduction mechanisms for the taste of amino acids.

Amino acids are important taste stimuli for a variety of animals. One animal model, the channel catfish, I. punctatus, possesses sensitive taste receptor systems for several amino acids. Neurophysiological and biochemical receptor binding studies suggest the presence of at least three receptor pathways: one is a relatively nonspecific site(s) responsive to short-chain neutral amino acids such as L-alanine (L-ALA); another is responsive to the basic amino acid L-arginine (L-ARG); still another is a low affinity site for L-proline (L-PRO). Several possible transduction pathways are available in the taste system of this animal model for these amino acids. One of these, formation of inositol trisphosphate (IP3) and cyclic AMP (cAMP), is mediated by GTP-binding regulatory proteins, while another involves ion channels directly activated by stimuli. L-ALA is a potent stimulus to cAMP and IP3 accumulation, while L-ARG at low concentrations is without effect. On the other hand, L-ARG and L-PRO, but not L-ALA, are able to activate stimulus-specific and cation-selective channels in taste epithelial membranes reconstituted in phospholipid bilayers at the tips of patch pipettes. Preliminary studies using mouse taste tissue demonstrate that monosodium-L-glutamate (MSG) did not enhance production of IP3 or cAMP. However, in reconstitution experiments using taste epithelium of mouse, conductance changes due to MSG are observed. The specificity of this channel(s) and its uniqueness have yet to be determined.

Amino Acids↗
PubMed2004

[Etiology, diagnostic and therapeutic management of taste disorders].

Taste disorders can be subdivided in ageusia, which is the inability to detect any qualitative gustatory sensation and hypogeusia, which is a decreased sensitivity to all tastants. Dysgeusia or pargeusia is a distortion or perversion in the perception of a tastant in contrast to phantosmia, which is a perception of taste that occurs in the absence of a tastant. The site of lesion can usually be determined by history and clinical examination. History taking should always include the assessment of current and former medication. Conditions that interfere with access of a tastant to the taste bud are differentiated from conditions that either injure the receptor cell or damage the gustatory afferent nerves and the central pathways. Psychophysical taste evaluation includes identification of quality using sprays or taste strips and testing of intensity perception measuring threshold using the 3-drop technique. Moreover, measurement of taste in localized areas can be performed either with conventional chemicals or using an electrogustometer. Gustatory evoked potentials are not yet routinely elicited. Therapy has to be planned according to the cause of the disorder.

Diagnosis, Differential↗
PubMed2001

Changes in taste intensity perception following anterior temporal lobe removal in humans.

To investigate the role of the anterior temporal lobe in taste perception, we compared taste intensity estimations made by patients who had removal from either the left or the right anterior temporal lobe for the treatment of intractable epilepsy with a group of healthy control subjects. Estimations were made for five concentrations of each of four different tastes, as well as for five cards of varying saturations of gray, which served as a control task. A cross-modal magnitude estimation procedure was employed in which subjects used distance on a measuring tape to reflect intensity estimation. Distances were then transformed into logs, and the slope and the correlation with stimulus concentration or saturation was calculated. Correlation was taken as a measure of accuracy of estimation and slope was taken as a measure of perceived intensity. As predicted, repeated measures analysis of variance (ANOVA) revealed a significant difference between the control group and both patient groups in taste intensity estimations, but not for grayness, reflecting the importance of the anterior temporal lobe in low-level gustatory but not visual perception. Additionally, repeated measures ANOVA for slopes indicated that subjects in the right temporal group rated the bitter taste as more intense than did subjects in other groups, possibly reflecting increased intensity perception of the unpleasant bitter taste.

Adolescent↗
PubMed2002

Taste enhancements between various amino acids and IMP.

It is well known that a strong synergistic interaction of umami occurs between L-alpha-amino acids with an acidic side chain, such as L-Glu or L-Asp, and 5'-mononucleotides, such as inosine 5'-monophosphate (IMP). We tested taste interactions between various L-alpha-amino acids and IMP by the psychophysical method and found that taste enhancement occurred when IMP was added to several sweet amino acids, such as L-Ala, L-Ser and Gly. The enhanced quality of taste was recognized as umami, and was not blocked by the sweetness inhibitor +/-2-(p-methoxyphenoxy)propanoic acid. The total taste intensities of various concentrations of the amino acid and IMP mixtures were measured using magnitude estimation. The results showed that the potentiation ratios were larger than 1 in the cases of L-Ala, L-Ser and Gly. However, the ratio was approximately 1 in the case of D-Ala, which had an enhanced taste of sweetness. Thus the umami taste enhancement of several sweet L-alpha-amino acids by IMP was synergistic rather than additive as that of acidic amino acids.

Adult↗
PubMed2006

Taste deficits related to dental deafferentation: an electrogustometric study in humans.

Dental treatments, the prevalence of which increases with age, can cause orofacial somatosensory deficits. In order to examine whether they may also affect taste sensitivity, electrogustometric thresholds were measured at 9 loci on the tongue surface in 391 healthy non-smoking, non-medicated subjects. Results showed that the greater the number of deafferented teeth, the higher the thresholds. Irrespective of age, subjects with more than 7 deafferented teeth exhibited significantly higher thresholds than subjects with fewer than 7 deafferented teeth. Conversely, across age groups, no statistical difference was observed among subjects with no, or few, deafferented teeth. Hence, a taste deficit, which was not correlated to aging, was observed. An association was noticed between the location of taste deficits and the location of deafferented teeth. Higher thresholds at anterior sites, with no possible traumatic injury relationship, suggested that neurophysiological convergence between dental somatosensory and taste pathways - possibly in the nucleus tractus solitarius - could be responsible for these relative decreases of taste sensitivity when dental afferences were lacking. Among trigeminal contributions, lingual nerve and inferior alveolar nerve may synergize taste.

Adult↗
PubMed2003

Positional cloning of the human quantitative trait locus underlying taste sensitivity to phenylthiocarbamide.

The ability to taste the substance phenylthiocarbamide (PTC) has been widely used for genetic and anthropological studies, but genetic studies have produced conflicting results and demonstrated complex inheritance for this trait. We have identified a small region on chromosome 7q that shows strong linkage disequilibrium between single-nucleotide polymorphism (SNP) markers and PTC taste sensitivity in unrelated subjects. This region contains a single gene that encodes a member of the TAS2R bitter taste receptor family. We identified three coding SNPs giving rise to five haplotypes in this gene worldwide. These haplotypes completely explain the bimodal distribution of PTC taste sensitivity, thus accounting for the inheritance of the classically defined taste insensitivity and for 55 to 85% of the variance in PTC sensitivity. Distinct phenotypes were associated with specific haplotypes, which demonstrates that this gene has a direct influence on PTC taste sensitivity and that sequence variants at different sites interact with each other within the encoded gene product.

Alleles↗
PubMed2005

Genetic tracing shows segregation of taste neuronal circuitries for bitter and sweet.

The recent discovery of mammalian bitter, sweet, and umami taste receptors indicates how the different taste qualities are encoded at the periphery. However, taste representations in the brain remain elusive. We used a genetic approach to visualize the neuronal circuitries of bitter and sweet tastes in mice to gain insight into how taste recognition is accomplished in the brain. By selectively expressing a transsynaptic tracer in either bitter- or sweet and/or umami-responsive taste receptor cells, and by comparing the locations of the tracer-labeled neurons in the brain, our data revealed the potential neuronal bases that underlie discrimination of bitter versus sweet.

Animals↗
PubMed2005

Inhibition of signal termination-related kinases by membrane-permeant bitter and sweet tastants: potential role in taste signal termination.

Sweet and bitter taste sensations are believed to be initiated by the tastant-stimulated T1R and T2R G protein-coupled receptor (GPCR) subfamilies, respectively, which occur in taste cells. Although such tastants, with their significantly diverse chemical structures (e.g., sugar and nonsugar sweeteners), may share the same or similar T1Rs, some nonsugar sweeteners and many bitter tastants are amphipathic and produce a significant delay in taste termination (lingering aftertaste). We report that such tastants may permeate rat taste bud cells rapidly in vivo and inhibit known signal termination-related kinases in vitro, such as GPCR kinase (GRK)2, GRK5, and PKA. GRK5 and perhaps GRK2 and GRK6 are present in taste cells. A new hypothesis is proposed in which membrane-permeant tastants not only interact with taste GPCRs but also interact intracellularly with the receptors' downstream shutoff components to inhibit signal termination.

Animals↗
PubMed2003

Preexposure to the stimulus elements, but not training to detect them, retards human odour-taste learning.

Odours are judged to smell sweeter following simultaneous oral pairings with the tastant sucrose and sourer after parings with the tastant citric acid. This effect may result from human participants perceiving and encoding a unitary odour-taste percept. This study examined two factors thought likely to disrupt such encoding; (a) preexposure to the mixture elements and (b) training to spot the elements of taste-odour mixtures. Half of the participants were trained to identify tastes and smells and half received no training. All participants were preexposed to two odours (A, B) and two tastes (X, Y), followed by pairings of these stimuli (AX, BY) and then by pairings between two non-preexposed odours and the same tastes (CX, DY). This process was then repeated on a second session. Odour-taste learning was retarded following preexposure, but was unaffected by training. These findings suggest; (1) that odour-taste mixtures may be cognitively impenetrable and (2) that preexposure leads to encoding of A and B, which are then resistant to interference when further pairings are presented (i.e. AX, BY).

Journal Article↗
PubMed2001

Younger patients have a higher rate of recovery of taste function after middle ear surgery.

BACKGROUND: Although the chorda tympani nerve (CTN) is frequently damaged during tympanoplasty, little attention has been given to the patients' symptoms and taste function. OBJECTIVE: To investigate patients' symptoms and the functional recovery of taste after surgery using electrogustometry (EGM). DESIGN: Prospective study. PATIENTS: Analysis of 163 ears of 156 patients who underwent middle ear surgery from April 1997 through December 1999. There were 18 ears with noninflammatory diseases, 80 with chronic otitis media, and 65 with cholesteatoma. The patients' taste functions were examined 2 days before surgery and 2 weeks and 6 months after surgery. MAIN OUTCOME MEASURES: The taste disturbance before and after middle ear surgery and the relationship between age and the recovery rate of CTN function. RESULTS: Two weeks after surgery, the mean EGM threshold was elevated in all groups regardless of preservation or section of the CTN. Numbness in the tongue and taste disturbance were more frequently found in patients with preservation of CTN than in those with section of the CTN (P =.008 and P =.001, respectively). In patients with preservation of the CTN, 6 months after surgery, the recovery rate of EGM threshold was 83% in those aged 20 years or younger (P =.008 compared with the 2 older groups), 53% in the those aged 21 to 40 years, and 44% in those aged 41 to 60 years. CONCLUSION: Age is an important factor for recovery of taste function after middle ear surgery, which is useful information when explaining complications to patients.

Adolescent↗