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PubMed2004

Subclinical alteration of taste sensitivity induced by candesartan in healthy subjects.

AIMS: There have been case reports of taste disturbance for the angiotensin II receptor blockers losartan and valsartan, but not for candesartan. This study was undertaken to examine whether candesartan causes taste disturbance. METHODS: Candesartan cilexetil (4 mg day(-1)) or vehicle was given to healthy volunteers (n = 8) for 7 days in a randomized, double-blind, placebo-controlled, cross-over design with a 2-week washout period. Clinical gustometry using the filter-paper disc test and electrogustometry were sequentially performed before and at the end of each trial. Serum and salivary zinc concentrations were also measured. RESULTS: Detection thresholds of four basic tastes (sweet, salty, sour and bitter) determined by the paper disc test were significantly (P < 0.05 in all tests) worsened (i.e. score of test increased) after repeated dosing of the drug, although the subjects did not notice such changes. The mean +/- SEM (and 95% CI) scores of the four tastes at just before the seventh dosing of candesartan or vehicle was 3.38 +/- 0.32 (3.02, 3.74) and 2.63 +/- 0.18 (2.18, 3.08) for sweetness, 3.63 +/- 0.38 (4.49, 2.77) and 2.63 +/- 0.26 (3.27, 1.98) for salt, 4.01 +/- 0.42 (3.04, 4.98) and 2.61 +/- 0.32 (3.35, 1.87) for sourness, 4.01 +/- 0.38 (3.22, 4.80) and 2.99 +/- 0.33 (2.24, 3.74) for bitterness, for candesartan and placebo, respectively. Electrogustometry confirmed the candesartan-related taste disturbance. Serum and salivary zinc concentrations were not influenced by candesartan. CONCLUSIONS: These data suggest that candesartan subclinically reduces taste sensitivity after repeated dosing in healthy subjects. Because similar events are reported for losartan and valsartan in case reports, this adverse effect might be a class effect of angiotensin-II receptor blockers (ARBs).

Adult↗
PubMed2005

Angiotensin II receptor blocker-induces blunted taste sensitivity: comparison of candesartan and valsartan.

AIMS: To compare the degree of taste disturbance by candesartan and valsartan. METHODS: Candesartan cilexetil (4 mg day(-1)), valsartan (40 mg day(-1)), or vehicle was given to subjects (n = 8) for 13 days in a randomized, placebo-controlled, three-way crossover design with a 14-days washout period. Gustometry by filter-paper test and electrogustometry were performed before and at the end of each trial. Plasma renin activity and zinc concentrations in serum and saliva were measured. RESULTS: Detection thresholds of four basic tastes (sweet, salty, sour and bitter) by paper-disc test and electrogustometry were significantly worsened and plasma renin activity was elevated after the test, while the effects of two drugs did not significantly differ. These drugs did not affect zinc concentrations. CONCLUSION: Both candesartan and valsartan similarly alter taste sensitivity after the repeated dosing of the drug.

Adult↗
PubMed2003

Taste receptors for pyrrolizidine alkaloids in a monophagous caterpillar.

Caterpillars of Utetheisa ornatrix are monophagous on species of Crotalaria which they obtain pyrrolizidine alkaloids (PAs) for defense and which the males convert to a pheromone. We show that a taste receptor neuron in each of the lateral and medial galeal styloconic sensilla responds to PAs of three different types. Monocrotaline, commonly present in Crotalaria species, is the most strongly stimulating with thresholds of response below 10(-11) and 10(-9) M in the two sensilla. These are among the lowest known taste thresholds in any insect and are similar to the thresholds for PAs in a polyphagous arctiid caterpillar that also sequesters PAs and uses them as the source of male pheromone. The receptors also respond to heliotrine, a type of PA that is probably never encountered by the insects. Monocrotaline and senecionine N-oxide are shown in behavioral assays to be phagostimulants. The data show that there is no tight link between taste receptor sensitivity to specific PAs and hostplant selection in these caterpillars. Perhaps the adults are primarily responsible for hostplant selection.

Animals↗
PubMed2003

Improvement of taste sensitivity of the nursed elderly by oral care.

It has been suggested that oral care is essential for improving the quality of life (QOL). The aim of oral care involves not only maintenance of oral health but also enhancement of mastication and appetite by means of improving taste sensitivity. There are, however, few studies that have investigated the effect of oral care on taste sensitivity. In the present study, we focused on tongue brushing among oral care and examined the changes in taste sensitivities by mild tongue brushing in the nursed elderly. Ninety subjects, over 64 years old with ability to communicate, were divided into 2 groups, one was the cared group (subject's tongue was brushed) and the other was the control group (not brushed but rinsed). The thresholds for four primary tastes such as saltiness, sourness, sweetness and bitterness were measured before and after treatments using the whole mouth method. The mean recognition thresholds for salty and sour tastes significantly decreased after tongue brushing in the cared group, while those for all four tastes were not changed after mouth rinsing in the control group. The present result suggests that mild tongue brushing may enhance taste sensitivity of saltiness and sourness in the nursed elderly.

Aged↗
PubMed1990

Design issues in chemosensory trials.

Randomized clinical trials in taste and smell disorders have been infrequent, in part because of difficulties in both the design and the conduct of such trials. Hyposmia and hypogeusia, impairments of smell and taste, respectively, have a variety of causes, such as upper respiratory infection, head trauma, or laryngectomy. Once definitive diagnosis is established, eligibility and exclusion criteria may relate to etiology. Since the sense of smell is more acute at younger ages and since women can generally identify odors more accurately than men, either prestratification or poststratification should be considered. A control or comparison group is essential because, occasionally, chemosenses spontaneously return to normal. Patient recruitment may be difficult, depending to a large extent on self-referrals, with the exception of head injury cases. To enroll an adequate number of patients in a reasonable length of time usually requires participation of multiple clinical centers. Objective measurements of taste and smell must be reliably obtained before and after intervention. Design issues specific to chemosensory trials are discussed in the context of an example, a factorial design trial of surgery and steroids in patients with olfactory defects.

Humans↗
PubMedDate not supplied

Effect of antimicrobial and anti-inflammatory medications on the sense of taste.

Elderly individuals and HIV-infected patients have a disproportionate number of taste complaints relative to the general population, and these taste alterations are correlated with the use of medications. Clinical reports of taste disorders have been associated with many drugs, including antimicrobial and anti-inflammatory medications. The purpose of this study was to quantify the taste effects of 6 nonsteroidal anti-inflammatory drugs (NSAIDS) and 13 antimicrobial drugs. The six NSAIDS were: diclofenac sodium salt, fenoprofen calcium salt, ibuprofen, ketoprofen, nabumetone, and sulindac. The 13 antimicrobials were: acyclovir, ampicillin, atovaquone, dapsone, enoxacin, ethambutol, lomefloxacin HCl, ofloxacin, pentamidine isethionate, pyrimethamine, sulfamethoxazole, tetracycline HCl, and trimethoprim. These 19 medications were applied topically to the tongues of unmedicated young and elderly volunteers as well as unmedicated HIV-infected patients to measure the direct effect of the drug on taste receptors. Topical application of drugs to the apical tongue surface was used to mimic the situation in which the drug is secreted into the saliva. The main finding was that the taste qualities of these drugs were perceived as predominantly bitter, metallic, and/or sour, although several did not have a taste. Elderly subjects had higher thresholds than young subjects for one-third of the drugs that were tested. Thresholds for HIV-infected patients were statistically equivalent to young controls; however, HIV-infected patients rated the drugs as more intense at four times above the detection threshold than young subjects. Most of these drugs when applied directly to the tongue also modified the taste intensity of other tastants (e.g., NaCl, citric acid).

Administration, Oral↗
PubMed1995

The effect of head and neck irradiation on taste dysfunction: a prospective study.

Taste loss is a major cause of morbidity in patients undergoing head and neck irradiation. In a prospective study, 26 patients undergoing radical head and neck irradiation at the Royal Marsden Hospital, Sutton, and the Queen Elizabeth Hospital, Birmingham, were assessed for taste loss and xerostomia. Taste was tested using a subjective questionnaire and by objective taste testing with a series of solute solutions (sucrose, sodium chloride, urea and hydrochloric acid) at increasing concentrations, to determine the threshold level of taste sensation, both before and after radiotherapy. Xerostomia was assessed using a patient questionnaire. The volume of tongue and parotid contained within the high dose volume of the radiation treatment field was determined for each patient and correlated with the degree of objective and subjective taste loss as well as the degree of xerostomia. The results have shown that both objective (r = 0.59; P = 0.0016) and subjective taste loss (r = 0.78; P = 0.0001) was significantly associated with the proportion of tongue, but not parotid, contained within the radiation treatment field. The data gave no evidence to suggest any relationship between recovery of taste loss and volume of parotid or tongue irradiated. However, recovery of subjective taste loss, 1 month after completing radiotherapy was seen in two patients, both of whom had been treated using a wedge pair technique to avoid the contralateral area of the tongue. Changes in xerostomia were significantly correlated with the proportions of both tongue (r = 0.54; P = 0.004) and parotid (r = 0.82; P = 0.0001) within the radiation treatment fields.(ABSTRACT TRUNCATED AT 250 WORDS)

Head and Neck Neoplasms↗
PubMed1987

Interactions between sucrose, pain and isolation distress.

Two experiments were conducted that establish an opioid-based, functional-relationship between the taste of sucrose, pain threshold and distress vocalization in isolated 10-day-old albino rats. In the first experiment intraoral infusion of sucrose virtually doubled heat-withdrawal latencies. This elevation was naltrexone (0.5 mg/kg b.wt.) reversible. In the second experiment sucrose infusions caused a rapid and sustained diminution of distress vocalizations in rats totally isolated from dam and siblings. These are the first demonstrations of a causal relationship between a positive affective system and ones mediating pain and stress.

Animals↗
PubMed1975

Defects of taste and smell in patients with hypothyroidism.

Taste and smell functions were measured in 18 unselected patients with untreated primary hypothyroidism, and in 15 of the 18 patients after treatment with thyroid hormones. Before treatment, 9 of the 18 patients (50 per cent) were aware of some alteration in their sense of taste, and 7 of the 18 patients (39 per cent) were aware of some alteration in their sense of smell. Distoritions of tase (dysgeusia) and smell (dysosmia) were frequent complaints among the untreated patients; dysgeusia was observed by 7 patients (39 per cent) and dysosmia by 3 patients (17 per cent). Median detection and recognition thresholds for four taste stimuli salt (sodium chloride), sweet (sucrose), sour (hydrochloric acid) and bitter (urea), and for two smell stimuli (pyridine and nitrobenzene), were determined in each patient before and after treatment with thyroid hormones. Before treatment, decreased taste acuity (hypogeusia) for at least one stimulus was observed in 14 of the patients (83 per cent); the most common abnormalities were in the detection and recognition of bitter stimuli. Median detection thresholds for both smell stimuli were also markedly elevated (hyposmia) before therapy. Treatment with throid hormones largely reversed both the taste and smell defects. In one patient, taste and smell abnormalities were completely corrected after 16 days of treatment with thyroxine. This study indicates that taste and smell defects are common clinical abnormalities in primary hypothyroidism, and suggests that these defects may contribute to the anorexia and lack of interest in eating which are frequently observed.

Adult↗
PubMed1978

Smell and taste acuity in epileptic syndromes.

Taste and smell acuity were determined in 50 normal subjects and 48 epileptic patients by means of Henkin's method. Smell detection thresholds are greatly reduced in epileptic patients, mainly those suffering from partial seizures with complex symptomatology. Epileptic patients show also a reduced threshold for sweet and bitter taste. Age, sex and antiepileptic drugs do not affect taste and smell acuity. The significance of these findings in the pathogenesis of epileptic seizures is discussed.

Adult↗
PubMed2002

[Hearing disorders, dysosmia and dysgensia in patients undergoing irradiation for head and neck cancer].

UNLABELLED: The study included 30 patients who underwent irradiation for head and neck cancer in the Regional Oncology Center. Cobalt 60 was used to irradiate facial--cervical area bilaterally and parotid glands partially. Before and after the irradiation, audiometric test, examination for osmaesthesia and sense of taste were performed. MATERIAL AND METHOD: All patients underwent laryngologic examination. The sense of smell was estimated by using quantitative method (smell threshold test) and qualitative method (identificational test). Butyl alcohol with serial watery dilution from 0, 002 to 4 were used in the threshold tests. The identificational test relies on recognition of seven commonly known smells. The examination of taste was performed using the quantitative and qualitative methods. The assessment of taste threshold was made with electrogustometer. The organ of hearing was examined with tone audiometry. RESULTS: Audiometric examination of the patients before irradiation revealed sensorineural hearing loss in 14 patients while 6 patients proved mixed hearing loss. After the irradiation, 50% of the patients showed further hearing loss in the range of 5-30 dB. After the irradiation, the percentage of patients with anosmia was elevated to 20%. Normosmic patients were not observed. The quantitative method of the sense of taste before and after irradiation did not show a significant difference. Only 10% of patients who underwent irradiation recognized 4 basic tastes, 30% of them did not show the sense of taste in the qualitative method. CONCLUSION: 1. After the irradiation, 50% of the patients developed further hearing loss. 2. Olfactometric examination of the patients after laryngectomy showed different degree of hyposmia. 3. The quantitative method of smell performed in patients before and after irradiation showed no significant differences. 4. Distinct deterioration of taste recognition was observed in the qualitative method compared to the examination before irradiation.

Adult↗
PubMed2001

NaCl detection thresholds: comparison of Fischer 344 and Wistar rats.

Adult Fischer 344 (F344) rats fail to display any preference for NaCl solutions at concentrations typically preferred by other rat strains. To determine whether this behavior is due to a strain difference in NaCl detection threshold, a conditioned taste aversion (CTA) was first established to a suprathreshold concentration of NaCl (0.1 M). Then, a series of dilute NaCl solutions, ranging from 0.0 to 0.011 M NaCl, were presented to F344 (n = 16) and Wistar (n = 16) rats. The lowest concentration at which there was a reliable difference in the preference scores of conditioned and control rats was defined as the detection threshold. Results indicate that the detection threshold for NaCl lies between 0.001 and 0.002 M NaCl for both F344 and Wistar rats. The addition of the sodium channel blocker amiloride to the NaCl solutions raised the detection threshold 10-fold to 0.03-0.04 M NaCl for both strains of rats. These results suggest that the NaCl detection thresholds of F344 and Wistar rats are similar and that these strains do not differ in the degree to which amiloride raises this threshold.

Amiloride↗
PubMed1976

Comparative ultrastructure of vallate, foliate and fungiform taste buds of golden Syrian hamster.

A fine-structure study of the hamster fungiform, foliate and vallate taste buds was undertaken for comparative purposes. All three taste bud types shared in common composition of the dark cells, light cells, basal cells, nerve fibers and nerve endings and undifferentiated peripheral cells, but morphological difference existed among them. The foliate and vallate taste buds were quite similar in their ultrastructural morphology. Their dark cells displayed long apical necks, long apical microvilli, apical osmiophilic secretory granules and an abundant rough endoplasmic reticulum. The dark cells of the fungiform taste buds, however, showed no neck formation and lacked apical osmiophilic granules. They had short apical microvilli and relatively scant rough endoplasmic reticulum. There was no difference in the fine structure features of the light cells, basal cells and neural elements of different types of taste buds. Both light and dark cells were much more readily distinguishable in foliate and vallate buds than in fungiform buds at both light-and electron-microscopic levels. Foliate and vallate buds demonstrated homogeneous dense substance within the taste pores while fungiform pores were frequently empty. It is speculated that the differences in taste bud morphology may be due to their different lingual locations and/or may be a reflection of the differences in the inductive influences from different nerves. Furthermore, structural differences may be responsible for varying thresholds to different taste modalities.

Animals↗
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↗
PubMed1999

Alterations of chemosensory function in end-stage liver disease.

Taste and smell dysfunction has been documented in patients with both acute and chronic liver disease. The purpose of this study was to determine if chemosensory function is improved after restoration of hepatic function with liver transplantation. Nine subjects (seven women and two men) with end-stage liver disease participated in the study. Taste and smell detection and recognition thresholds were determined before and after transplantation. A significant improvement in detection of the taste of sodium chloride and the odor of phenethyl alcohol was found after transplantation. These findings may have clinical significance in food choices and nutritional status of these patients.

Adult↗
PubMedDate not supplied

Gustative sensitivity to glucose improvement in diabetics after sulphonylurea.

Sensitivity of the gustatory receptor to glucose has been studied in 20 diabetic patients given tolbutamid and glibenclamid as treatment or examined in the tolbutamid tolerance test (TTT). Tolbutamid and glibenclamid treatment significantly improves the diabetic taste for glucose, both for detection threshold (DT) (p less than 0.01) and recognition threshold (RT) (p less than 0.001). Also in TTT there is a significant improvement of taste reception: DT falls at 2 h (p less than 0.05), RT falls more slowly at 3 h (p less than 0.05). There is no direct correlation between perception for sweet and glycemia and insulinemia increase in TTT. Our results suggest that glucose receptivity is dependent on a receptor glucose-insulin complex, and tolbutamid (and glibenclamid) besides its capacity to stimulate insulin secretion has even a peripheral action, at this receptor level.

Adolescent↗
PubMed2000

Decline in taste and odor discrimination abilities with age, and relationship between gustation and olfaction.

It is important to learn about changes in both taste and odor perceptions with increasing age, because the taste of foods we encounter in our daily life is strongly affected by their smell. This study discusses the difference in qualitative taste and odor discrimination between the elderly and the young. Tastants and odorants used in this study were presented not as single stimuli but as a taste mixture (sucrose and tartaric acid) and an odor mixture (beta-phenylethyl alcohol and gamma-undecalactone). The results showed that quality discrimination abilities of the elderly subjects for both taste and odor were significantly lower than those of the young subjects, indicating a decline in quality discrimination abilities related to age. Also, a moderate but significant correlation was observed between the taste discrimination ability and the odor discrimination ability. We measured thresholds for single-taste and odor components in mixtures and compared them between the elderly and the young to investigate the cause for these findings.

Adult↗
PubMed1978

Pituitary-adrenal axis and oral morphine consumption in rats.

Removal of the pituitary gland in rats leads to suppression of oral morphine and quinine intake behavior. Experiments measuring oral intake of solutions containing graded concentrations of morphine or quinine, revealed that the detection acuity for bitter taste is changed in hypophysectomized (hypox) animals. Treatment of these rats with ACTH 1--24 restored oral morphine intake towards that on intact rats. Morphine consumption in hypox rats was not affected by administration of ACTH 4--10 or ACTH 11--24, but was normalized by treatment with corticosterone. Adrenalectomy also diminished oral morphine intake. It is concluded that hypophysectomized animals refuse a morphine solution because their threshold for bitter taste quality is altered, presumably due to a diminished release of corticosteroids.

Adrenalectomy↗