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PubMedDate not supplied

Pain sensitivity and saccharin intake in alcohol-preferring and -nonpreferring rat strains.

The experiments were designed to study the association between consumption of palatable 0.1% (w/v) saccharin solution, voluntary drinking of 10% (v/v) ethanol solution, and pain sensitivity measured with the hot plate test. Rat lines that were genetically selected for high alcohol consumption (P and AA rats), alcohol-preferring Fawn Hooded (FH) rats and their F2[FH x FRL] hybrids, and the Maudsley Nonreactive strain (MNRA) had a high propensity to consume saccharin that resulted in a significant (almost twofold; p < 0.05) increase in their daily fluid intake when saccharin was available. These strains also had lower pain thresholds in the hot plate test than did their parallel strains [NP, ANA, Maudsley Reactive (MR)]. Most alcohol-nonpreferring strains [NP, ANA, and Flinders Resistant Line (FRL)] had preference ratios for saccharin about as high as those of the alcohol-preferring rats but, unlike the high alcohol drinkers, they did not increase their total fluid intake when saccharin was available. The mean saccharin intakes of the lines were strongly correlated with their alcohol drinking during the first 5 days, whereas their latencies on the hot plate were inversely related to their change in alcohol drinking with experience. The results are consistent with an endogenous opioid mechanism being involved in alcohol drinking.

Alcohol Drinking↗
PubMed1992

Preference can be more powerful than detection of oddity as a test of discriminability.

Subjects presented with sets of three samples, two of distilled water and one of tap water, were significantly more consistent in choosing the tap water as preferable than they were in identifying it as the odd sample in the set. The result is opposite to the prediction of high-threshold models of sensory discrimination, which say that if a difference is not noticed, preferences will be random, whereas if a difference is noticed, preferences may still be in either direction. The result can be quantitatively explained by a model advanced by Frijters to explain an analogous anomaly found with the triangle test used in the food industry. Applying his model to the observed proportions yields essentially equivalent estimates of sensory difference (d' = 1.5, approximately) from the two tasks, and a direction of preference almost unanimously in favor of the tap water that was used. Since the model predicts that the proportion of subjects choosing the odd item will depart further from chance in the preference task than in the oddity task, the former has greater power to reject the null hypothesis of no sensory difference if one exists and if preference is overwhelmingly in one direction.

Adult↗
PubMed2001

Effects of sweetened ethanol solutions on ethanol self-administration and blood ethanol levels.

The enhancement of voluntary self-administration of ethanol by sucrose or saccharin was tested in conjunction with measurements of blood ethanol levels. Adult male rats were given access to both tap water and one of five solutions: 0.125% saccharin, 10% sucrose, ethanol, saccharin+ethanol, or sucrose+ethanol. The rats receiving the sucrose+ethanol solution drank consistently more ethanol (>5 g/kg/day) than did the rats receiving the saccharin+ethanol solution (<3 g/kg/day) or ethanol only (<2 g/kg/day). Both sweetened solutions produced higher ethanol consumption during these periods than ethanol alone. However, no significant differences in blood ethanol levels were found between the sucrose+ethanol and saccharin+ethanol conditions, when tested at different intervals on Day 44 or Day 45 of ethanol consumption. Following 45 days of consumption, no change in the bicuculline seizure threshold was observed in the ethanol-consuming rats compared to the controls. In a separate study using 90 naive rats, rats were gavaged with ethanol (1, 2, or 3 g/kg) containing either 10% sucrose (n=10 for each dose of ethanol), 0.125% saccharin (n=10 for each dose of ethanol), or ethanol alone (n=10 for each dose of ethanol), and blood was collected from the tip of the tail 30, 60, 180, 300, and 540 min later and analyzed for ethanol concentrations. Sucrose significantly decreased the resultant blood ethanol levels at several time points following gavage. These results indicate that sucrose can significantly alter blood ethanol levels and that chronic self-administration of a sweetened ethanol solution for 6 weeks does not produce ethanol dependence.

Alcohol Drinking↗
PubMed1991

Opioid mediation of odor preferences induced by sugar and fat in 6-day-old rats.

Intraoral infusions of sucrose, fat or polycose reduce ultrasonic vocalizations during isolation, and increase pain threshold in infant rats. These effects are naltrexone reversible. The present study determined whether these substances, when paired with an odor, caused a change in preference for that odor. In 6-day-old rats, pairing orange odor with intraoral infusions of sucrose or corn oil, but not polycose, water, mineral oil or 0.01% quinine hydrochloride, caused a substantial increase in preference for orange. Preference formation was blocked by systemic injection of naltrexone (0.25 mg/kg) prior to pairing orange with either sucrose or corn oil. Moreover, preference expression was prevented by naltrexone injection prior to testing. Thus certain substances thought to reduce stress in infant rats via endogenous opioid release can also cause preference for substances that predict their occurrence. Preference formation depends upon the availability of endogenous opioids. Preference expression reflects the conditioned stimulus causing opioid release.

Animals↗
PubMed2005

Functional MRI detection of activation in the primary gustatory cortices in humans.

Magnetoencephalography (MEG) has recently revealed that the transitions between the parietal operculum (Pop) and the insula (area G) and the ventral end of the central sulcus (cs) were activated with the shortest latency by instrumental gustatory stimulation, which suggests that the location of the primary gustatory area is in these two regions. However, studies using other noninvasive brain-imaging methods such as positron-emission tomography or functional magnetic resonance imaging (fMRI) with manual application of tastants into the mouth have been unable to confirm this. The present study examined cortical activation by repetitive stimulation of the tongue tip with 1 M NaCl with a computer-controlled stimulator and used fMRI to detect it. In individual brains, activations were detected with multiple comparisons (false discovery rate) across the whole brain corrected (threshold at P < 0.05) at both area G and frontal operculum (Fop) in 8 of 11 subjects and at the rolandic operculum (Rop) in 7 subjects. Activations were also found at the ventral end of the cs (n = 3). Group analysis with random-effect models (multiple comparison using familywise error in regions of interest, P < 0.02) revealed activation at area G in both hemispheres and in the Fop, Rop, and ventral end of the cs on the left side. The present study revealed no activation on the gyrus of the external cerebral surface except for the Rop. Taking MEG findings into consideration, the present findings strongly indicate that the primary gustatory area is present at both the transition between the Pop and insula and the Rop including the gray matter within a ventral part of the cs.

Adult↗
PubMed2005

Effects of a sour bolus on the intramuscular electromyographic (EMG) activity of muscles in the submental region.

A sour bolus has been used as a modality in the treatment of oropharyngeal dysphagia based on the hypothesis that this stimulus provides an effective preswallow sensory input that lowers the threshold required to trigger a pharyngeal swallow. The result is a more immediate swallow onset time. Additionally, the sour bolus may invigorate the oral muscles resulting in stronger contractions during the swallow. The purpose of this investigation was to compare the intramuscular electromyographic activity of the mylohyoid, geniohyoid, and anterior belly of the digastric muscles during sour and water boluses with regard to duration, strength, and timing of muscle activation. Muscle duration, swallow onset time, and pattern of muscle activation did not differ for the two bolus types. Muscle activation time was more tightly approximated across the onsets of the three muscles when a sour bolus was used. A sour bolus also resulted in a stronger muscle contraction as evidenced by greater electromyographic activity. These data support the use of a sour bolus as part of a treatment paradigm.

Adult↗
PubMed2006

Effects of oxygen and turmeric on the formation of oxidative aldehydes in fresh-pack dill pickles.

Hexanal, pentanal, and heptanal were found to be normal components of commercially processed, fresh-pack dill pickles. Hexanal and pentanal were present at concentrations severalfold higher than their odor detection thresholds. These aldehydes were also found in pickles that were packed in the laboratory under anaerobic conditions. Injection of oxygen into pickles prepared in anaerobic conditions resulted in the production of increasing the amounts of hexanal, heptanal, and pentanal. Hexanal, pentanal, (E)-2-hexenal, and heptanal levels were negatively correlated with the addition of turmeric in dill pickles with oxygen injected into the jar, indicating that the curcumin present in turmeric is an effective antioxidant in this product. At commercial coloring levels (250 mg/L), turmeric addition maintained aldehyde levels near the concentrations found in commercial fresh-pack pickles packaged in glass containers when oxygen was added in amounts comparable to that which would enter a plastic container during a 1-year storage period. Therefore, the addition of turmeric appears to be an effective approach to minimize the formation of oxidative off-flavors in pasteurized dill pickles that may result from the oxygen permeability of plastic containers.

Aldehydes↗
PubMedDate not supplied

[Perception of sweet and salty flavors in different population groups].

The flavour perceived by humans when eating varies depending on age, gender, habits, emotional status, etc. The present study reflects the changes in the perception of sweet and salt flavours among different population groups depending on age, with an assessment, for each flavour, of the threshold concentration for the detection of these flavours. Triangular discrimination sensorial tests were performed in three groups, with thirty members in each, classified to represent young, adult and elderly age groups. With regard to sweet flavours, the groups of young people and adults distinguished the different sample at 0.1% of sugar for 95% and 99% significance levels, whereas the elderly required the concentration to reach 1% at both levels before they could distinguish the sugar solution from water. In the case of salt flavours, young people are able to detect the different sample at the lowest concentration level, for both levels of significance. Adults significantly distinguished the sample containing 0.05% of salt, at the 95% significance level, whereas the elderly needed a concentration of 0.1% for both levels of significance. Age-dependent variations in response were observed. As age increases, greater concentrations are required in order to distinguish the salt or sweet solutions from the samples containing only water.

Adult↗
PubMed2005

[A transcultural study on stirred strawberry yogurt: consumer acceptability versus sensory quality with trained panel].

The present work was designed in order to obtain the cut off point, to be used in a shelf life study on whole stirred strawberry yogurt. The study was simultaneously carried out in Argentina, Chile and Costa Rica, assaying the same kind of product, elaborated in each one of the countries. The sensory quality parameters obtained from trained panelists and the consumers acceptability, were correlated by using the cut off point methodology through a quality evaluation by the Karlsruhe scale. According to preliminary studies, the storage at 42 degrees C produced considerable damage on parameters such as pH, acidity (volumetric assay), viscosity and sensory quality. For each sample, the cut off point was determined. This value corresponds to the threshold score for the sensory quality, where the consumer starts to perceive negative changes in the product, when comparing with the fresh product. The rejection percentage was also calculated according to the cut off point. The cut off points and the percentage of rejection obtained by the three participating countries were similar. Data obtained from Costa Rica showed changes in color, acidity and rancidity. Argentinean yogurts developed acidity that had a negative effect on texture, appearance and residual flavors. Chilean samples presented a sensory quality that remains almost without change through the studied time. The differences of the deterioration pattern amongst the three countries, demonstrates that the products are different in formulation and elaboration process, in spite of been the same kind of yogurt. This could be explained by differences specified in the regulation of each country.

Adult↗
PubMed2000

Detection of guaiacol produced by Alicyclobacillus acidoterrestris in apple juice by sensory and chromatographic analyses, and comparison with spore and vegetative cell populations.

Spoilage of fruit juice by Alicyclobacillus acidoterrestris is characterized by a distinct medicinal or antiseptic off odor attributed to guaiacol, a metabolic by product of the bacterium. Detection of low populations of A. acidoterrestris that would precede sensory detection of guaiacol would enable juice processors to select appropriate processing and storage conditions that would minimize or eliminate spoilage. The objective of this study was to determine the recognition threshold of guaiacol in apple juice by sensory analysis and the population of A. acidoterrestris and incubation time at 21 and 37 degrees C necessary for chemical detection of guaiacol. Commercially sterilized apple juice (pH 3.54 +/- 0.04, 11.3 +/- 0.3 degrees Brix) was inoculated with a five-strain mixture of A. acidoterrestris spores (2.98 log10 CFU/ml) and stored at 21 or 37 degrees C for up to 61 days. Using an experienced sensory panel and the forced-choice ascending concentration method of limits, the best estimate threshold (BET) for recognition of guaiacol added to uninoculated apple juice was 2.23 ppb. Numbers of A. acidoterrestris spores and cells in inoculated juice remained constant during the 61-day storage period; however, the panel detected (P < or = 0.01) guaiacol in juice stored at 37 degrees C within 8 days. At three of four sampling times ranging from 13 to 61 days at which the sensory panel detected (P < or = 0.001) guaiacol, concentrations of 8.1 to 11.4 ppb were detected by chromatographic analysis. The panel detected (P < or = 0.1 to P < or = 0.01) guaiacol in five samples stored at 21 to 37 degrees C for 8 to 61 days in which the compound was not detected by chromatographic analyses. It appears that guaiacol content in apple juice inoculated with A. acidoterrestris is not always correlated with numbers of cells, and the limit of sensitivity of chromatographic quantitation of the compound is higher than the BET.

Bacillus↗
PubMed2002

Chemical characterization of the aroma of Grenache rosé wines: aroma extract dilution analysis, quantitative determination, and sensory reconstitution studies.

The aroma of a Grenache rosé wine from Calatayud (Zaragoza, Spain) has been elucidated following a strategy consisting of an aroma extract dilution analysis (AEDA), followed by the quantitative analysis of the main odorants and the determination of odor activities values (OAVs) and, finally, by a series of reconstitution and omission tests with synthetic aroma models. Thirty-eight aroma compounds were found in the AEDA study, 35 of which were identified. Twenty-one compounds were at concentrations higher than their corresponding odor thresholds. An aroma model prepared by mixing the 24 compounds with OAV > 0.5 in a synthetic wine showed a high qualitative similarity with the aroma of the rosé wine. The addition of compounds with OAV < 0.5 did not improve the model, whereas the aroma of a model containing only odorants with OAV > 10 was very different from that of the wine. Omission tests revealed that the most important odorant of this Grenache rosé wine was 3-mercapto-1-hexanol, with a deep impact on the wine fruity and citric notes. The synergic action of Furaneol and homofuraneol also had an important impact on wine aroma, particularly in its fruity and caramel notes. The omission of beta-damascenone, which had the second highest OAV, caused only a slight decrease on the intensity of the aroma model. Still weaker was the sensory effect caused by the omission of 10 other compounds, such as fatty acids and their ethyl esters, isoamyl acetate, and higher alcohols.

Chromatography, Gas↗
PubMed1987

Quantitative structure-activity relationships of the bitter thresholds of amino acids, peptides, and their derivatives.

Bitter thresholds of a total of 93 amino acids, peptides, and their derivatives were analyzed quantitatively by use of hydrophobicity parameters reported for amino acid side chains and those for the whole molecules estimated from partition coefficients obtained experimentally. We also explored the steric parameters that best explained the variation in the intensity of bitterness attributable to the molecular shape. The results showed that the total length along the zigzag peptide backbone chain of the molecule is an important factor. The bitterness of nonzwitterionic N-acyl and ester derivatives and that of neutral N-acyl ester derivatives were expressed by a single, common equation together with those of zwitterionic amino acids and peptides. Thus the interaction via the charge with the receptor site was probably not an indispensible factor for triggering of the bitter sensation. This study, together with earlier ones, may serve as a prototype of approaches toward unraveling structure-activity relationships of complex molecules like amino acids, peptides, and their derivatives that are of medicinal or agricultural importance.

Amino Acids↗
PubMed2000

Effects of flavour amplification of Quorn and yoghurt on food preference and consumption in relation to age, BMI and odour perception.

Since the food habits of many elderly people are inadequate, the first experiment of the present study tested whether flavour amplification induces changes in preferences for and consumption of food and thus might result in a nutritional benefit. Two panels, one of 260 and one of 120 subjects, aged 19-98 years, took part in the study in which preferences for flavour-amplified yoghurt and Quorn were measured. For both products, only a few of the young subjects (20%) preferred the high flavour level; the percentage of subjects preferring the high flavour levels increased with age. These changes were highly significant. In a second experiment, participants received, under ad libitum conditions over 2 d in random order, a dish of yoghurt with either a high or a low flavour level. When adjusted for total consumption quantity, consumption of the highly flavoured yoghurt was not significantly correlated with age (r -0.03, P = 0.35). In a third experiment, odour perception was measured by determining the detection threshold for isoamylacetate. BMI values were obtained and the relationships between BMI and odour perception, age, preference and consumption were assessed in the age group 40-65 years. A significant correlation was observed between age and BMI (r 0.51, P < 0.0005). No significant correlation was observed between BMI and relative consumption of highly flavoured yoghurt (r -0.14, P = 0.14). A significant correlation was observed between BMI and preference for flavour-amplified yoghurt (r 0.35, P < 0.001). However, no significant correlation was observed between BMI and odour perception (r 0.07, P = 0.32). With increasing age, a combined influence of age, sex, BMI and odour perception on food preference is to be expected. According to our multiple regression analysis, BMI showed a significant partial regression coefficient (standardized beta 0.36, P = 0.03). In conclusion, flavour amplification of food for older adults deserves attention, but specific approaches, which are tailored to the candidate food systems and older adult target groups, are needed.

Adult↗
PubMed2003

Nicotine-conditioned locomotor sensitization in rats: assessment of the US-preexposure effect.

In rats, stimulus-nicotine associations can be altered by preexposure to the nicotine US (unconditioned stimulus). This alteration differs with the conditioning preparation. In a conditioned taste avoidance preparation, preexposure to nicotine weakens conditioning. In contrast, nicotine preexposure enhances acquisition of a nicotine-conditioned place preference. No one has examined the effects of US preexposure on nicotine locomotor conditioning. In three separate experiments, we assessed the effects of nicotine preexposure on the subsequent expression of conditioned hyperactivity produced by a nicotine US. We found evidence for nicotine-conditioned locomotor sensitization in non-preexposed rats that received repeated pairings of a distinct context with the psychomotor effects of a 0.42 mg/kg dose of nicotine (free base). Conditioning was not observed at lower nicotine doses (0.18 and 0.11 mg/kg) in non-preexposed rats. Preexposure to the 0.42 and 0.18 mg/kg doses of nicotine (3 or 9 days) attenuated acute locomotor suppression and enhanced the development of locomotor sensitization to that same dose. Despite similar qualitative shifts in the locomotor profile induced by preexposure to the nicotine US, conditioned hyperactivity was only altered after 3 or 9 days of preexposure at the 0.18 mg/kg dose. Thus, similar to place conditioning, nicotine preexposure can enhance the subsequent effectiveness of the nicotine US in a locomotor conditioning preparation.

Analysis of Variance↗
PubMed1987

[Peripheral somatic and autonomic nerve functions in patients with occupational vibration disease].

In order to evaluate the functions of the peripheral somatic nerve and autonomic nerve in patients with occupational vibration disease objectively and quantitatively, four examinations were performed on twenty 44-63 yr old patients with occupational vibration disease and their total operating time ranged from 5,000 to 43,750 h. 1) Motor nerve conduction velocities (MCV) and sensory nerve conduction velocities (SCV) of the ulnar and median nerves were measured using conventional methods. 2) Electrogustatory thresholds under the controlled area of the chorda tympani nerve were measured by Tomita's method using an electrogustometer (610-M, M.E.C.). 3) Dopamine-beta-hydroxylase (DBH) activity in blood was assayed by the photometric assay of Nagatsu and Udenfriend. 4) Coefficient of variation of R-R interval in ECG (CVR-R) was measured after 15-min-resting in supine position by using a R-R interval analyzer (Autonomic R 100, M.E.C.). The results of these examinations were compared with those of special examinations for the diagnosis of vibration disease. In patients with occupational vibration disease, MCV and SCV of the ulnar and median nerve were lower in value than those in age-matched healthy controls. In particular, MCV of the ulnar nerve, MCV and SCV of the median nerve were significantly lower in the patients than in the controls. Nerve conduction velocities were significantly correlated with skin temperature and nailpress test, though diminished nerve conduction velocities observed in vibration disease patients were considered to be attributable to peripheral circulatory disturbance.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Role of renin-angiotensin-aldosterone system in NaCl appetite of rats.

A variety of experimental paradigms is now known to induce an appetite for NaCl solutions in rats. These include 1) bilateral adrenalectomy; 2) hypothyroidism; 3) salivariectomy; and 4) administration of hydrochlorothiazide, metyrapone, estrogen, methylxanthines, captopril, propranolol, large doses of deoxycorticosterone acetate, and intraperitoneal isotonic glucose or subcutaneous polyethylene glycol. A point of commonality among these is that a reduction in preference threshold accompanies the appetite for NaCl in all cases thus far tested. An additional point is the fact that each paradigm inducing a salt appetite, except salivariectomy, can be linked to an effect on the renin-angiotensin-aldosterone system. The level of angiotensin II in the brain may play a role in the induction of a salt appetite in the rat. It is clear, however, that modest doses of mineralocorticoid hormones, given in conjunction with the stimulus producing the salt appetite (e.g., adrenalectomy, thyroidectomy, or treatment with captopril), reduces NaCl intake to control level. Although this effect can be partially explained in most cases by the consequent reduction in angiotensin II production, the salt appetite that occurs when mineralocorticoid concentration in blood is high and angiotensin II concentration is low, or when both are low, requires another explanation. This may be related to the effect of mineralocorticoid hormones on salivary sodium concentration. The role of the concentration of sodium in saliva on intake of NaCl solution provides an alternative explanation for the induction of a salt appetite in rats and merits additional study.

Adrenalectomy↗
PubMed1987

Caffeine enhancement of saccharin but not cyclamate flavor avoidance.

The present experiments were designed to assess whether caffeine, a substance that potentiates human perception of some artificial sweeteners, might also enhance perception of such substances by rats. In Experiment 1, rats were given varied concentrations of saccharin, cyclamate, and caffeine in 2-choice tests. 'Indifference thresholds' for these substances were 3.9 X 10(-4) M, 1 X 10(-3) M, and 1.6 X 10(-7) M, respectively. In Experiment 2, concentrations of saccharin and cyclamate just above and below indifference were used as stimuli in a flavor avoidance learning (FAL) paradigm. 'Suprathreshold' concentrations of saccharin and cyclamate produced reliable FAL while 'subthreshold' concentrations did not. In Experiment 3, rats were exposed to a low concentration of caffeine followed by presentations of subthreshold concentrations of saccharin or cyclamate as stimuli in a FAL paradigm. Saccharin FAL was observed but cyclamate FAL was not, suggesting that caffeine preexposure selectively potentiated detection of saccharin. In Experiment 4, animals were given saccharin or cyclamate with or without prior exposure to caffeine in a FAL paradigm. During subsequent tests, animals were presented with saccharin or cyclamate following exposure to caffeine saccharin or cyclamate mixed with caffeine saccharin or cyclamate alone. Saccharin FAL was observed following caffeine preexposure, but mixing with caffeine had no effect. These findings of selective potentiation are consistent with previous studies of human sensitivity after caffeine preexposure. Moreover, the present results support the notion that inhibitory A1 adenosine receptors are involved in modulating the perceived intensity of some flavors.

Animals↗
PubMed2006

Does the chorda tympani nerve confer general sensation from the tongue?

OBJECTIVE: Patients often complain of numbness of the tongue after otologic procedures; this symptom may occur with or without taste alterations. The purpose of this study was to objectively assess possible changes in the general sensation of the tongue in patients undergoing middle ear surgery. STUDY DESIGN AND SETTING: Thirty-three individuals were included in this prospective controlled clinical study conducted at a tertiary referral center. Fifteen patients underwent middle ear surgery and 18 volunteers served as a control group. Subjects underwent objective tests to assess general sensation of the tongue before and twice after surgery. RESULTS: Forty-seven percent of the patients complained of numbness or tingling of the tongue shortly after surgery. In these patients, a significant reduction in sensitivities to light touch and 2-point discrimination on the operated side were noted at that time (P < 0.01; P < 0.009 respectively). Values returned to baseline on subsequent evaluations. No sensitivity change was noted for the contralateral hemi-tongue. CONCLUSION: Objective changes in the general sensory function of the tongue correlated with post-operative clinical symptoms experienced by patients. The results of this study support the notion that the chorda tympani nerve confers general sensation from the tongue. EBM RATING: A-1b.

Adult↗