Cloning and characterization of a novel mGluR1 variant from vallate papillae that functions as a receptor for L-glutamate stimuli.
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The present experiment examined the individual and combined effects of systemic injection and oral ingestion of lithium chloride (LiCl) on both within and across session shifts in palatability. Male rats fitted with intraoral cannulae received two conditioning days in which they were injected with either LiCl or sodium chloride (NaCl) and were then presented with brief intraoral infusions of a sucrose plus LiCl or NaCl solution. The individual taste reactivity responses during the intraoral infusions were videotaped and later analyzed for response frequency. Forty-eight hours after the second conditioning day the same sucrose plus salt solution was presented again in the absence of any injection. The present results demonstrate that systemic injections of LiCl result in profound within session and across session decreases in ingestive responding accompanied by increased active and passive aversive responses. Animals receiving LiCl by injection as well as ingestion demonstrated an exaggerated response. Rats which received LiCl only through intraoral infusions produced the same pattern of decreased ingestive responding to the sucrose plus salt flavored tastant on each test trial suggesting little or no across session conditioning effects. A two process model by which animals may regulate toxicosis is discussed.
It has been argued whether the 'umami substances' such as monosodium glutamate (MSG) and disodium 5'-guanylate (GMP) stimulate the salt receptor or the unique receptor to the umami substances. We examined effects of amiloride, which inhibited the canine chorda tympani nerve responses to salts such as NaCl, KCl and NH4Cl, in a competitive manner, on the nerve responses to the umami substances and differentiated between the umami and salt components. Amiloride shifted the dose-response curves for MSG to a higher concentration region, suggesting that amiloride inhibits the response to MSG in a competitive manner. The response to GMP alone and that induced by synergism between relatively low concentrations of MSG and GMP were not inhibited by amiloride. These results suggested that the response to MSG alone is the salt response and the response to GMP alone or that induced by the synergism is the umami response. The presence of MSG shifted the dose-response curves for GMP to a lower concentration region, suggesting that MSG increases the affinity of GMP to umami receptors. The present results favor the conclusion that GMP acts as an agonist and MSG acts as a modulator for the umami receptor in the dog. The synergism can be explained by an allosteric model where the umami receptor is assumed to have two binding sites, one for GMP and another for MSG.
OBJECTIVE: To compare children's food preferences longitudinally and identify factors related to food preferences. DESIGN: Mothers completed the Food Preference Questionnaire for children at 2 to 3 years of age (T1), 4 years (T2), and 8 years (T3) and for themselves at T1 and T3. Both groups completed a Food Neophobia Scale at T3. SUBJECTS: 70 child/mother pairs who had participated continuously in the longitudinal study. STATISTICAL ANALYSES PERFORMED: Changes in food preferences over time were tested with paired t tests and correlations. Consistency percentages were calculated by summing the consistent matches (like/like) for each food between two time periods. Similarly, concordance percentages were calculated for child/mother pairs by summing the concordant matches for each food. General linear models were developed to identify influences on children's food preferences. RESULTS: Although children liked most foods, the number of liked foods did not change significantly during the 5 to 5.7 years of the study. The strongest predictors of the number of foods liked at age 8 years (R2=0.74) were the number liked at 4 years (P<.0001) and the food neophobia score (P=.0003). Newly tasted foods were more likely to be accepted between T1 and T2 than T2 and T3. Mothers' and children's food preferences were significantly but moderately related. Foods disliked by mothers tended not to be offered to children. APPLICATIONS/CONCLUSIONS: The important role of children's early food preferences is confirmed by this study. Mothers influence children via their own preferences, which may limit foods offered to children.
One mechanism of salt taste transduction by gustatory receptor cells involves the influx of cations through epithelial sodium channels that can be blocked by oral application of amiloride. A second mechanism is less clearly defined but seems to depend on electroneutral diffusion of the salt through the tight junctions between receptor cells; this paracellular pathway is insensitive to amiloride. Because the first mechanism is more sensitive to sodium salts and the second to nonsodium salts, these peripheral events could underlie the ability of rats to discriminate sodium from nonsodium salts on the basis of taste. Behavioral experiments indicate that amiloride, at concentrations that are tasteless to rats, impairs a rat's ability to discriminate NaCl from KCl and may do so by making both salts taste like KCl. In the present study, we examined the neural representation of NaCl and KCl (0.05-0.2 M), and mixtures of these salts with amiloride (0, 3, and 30 microM), to explore the neural correlates of this behavioral result. NaCl and KCl were represented by distinct patterns of activity in the nucleus of the solitary tract. Amiloride, in a concentration-dependent manner, changed the pattern for NaCl to one more characteristic of KCl, primarily by reducing activity in neurons responding best to NaCl and sucrose. The effect of amiloride concentration on the response to 0.1 M NaCl in NaCl-best neurons was virtually identical to its effect on behavioral discrimination performance. Modeling the effects of blocking the amiloride-insensitive pathway also resulted in highly similar patterns of activity for NaCl and KCl. These results suggest that activity in both the amiloride-sensitive and -insensitive pathways is required for the behavioral discrimination between NaCl and KCl. In the context of published behavioral data, the present results suggest that amiloride-sensitive activity alone is not sufficient to impart a unique signal for the taste of sodium salts.
Three brands of beer of varying alcohol content were presented to separate groups of male rats. The consumption data indicated, firstly, an inverse relationship between acceptability of the beer and its alcohol content. The data also indicated that the acceptability of full-strength beer could be augmented by prior exposure to low-alcohol and alcohol-free beer. The results are discussed with reference to orosensory- and inebriation-based models of alcohol consumption.
Milk and dairy products may contain microorganisms capable of secreting lipases that cause sensory defects and technological problems in the dairy industry. In this study, the effects of thermal and high-intensity pulsed electric field (HIPEF) treatments on an extracellular lipase from Pseudomonas fluorescens, suspended in a simulated skim milk ultrafiltrate (SMUF) have been evaluated. Heat treatments applied were up to 30 min from 50 to 90 degrees C. HIPEF treatments were carried out using pilot plant facilities in a batch or continuous flow mode, where treatment chambers consisted of parallel and coaxial configuration, respectively. Samples were subjected to up to 80 pulses at electric field intensities ranging from 16.4 to 37.3 kV/cm. This resulted in a lipase that was quite resistant to heat and also to HIPEF. High (75 degrees C-15 s) and low pasteurization treatments (63 degrees C-30 min) led to inactivations of 5 and 20%, respectively. Using the batch-mode HIPEF equipment, a 62.1% maximum activity depletion was achieved after 80 pulses at 27.4 kV/cm. However, when HIPEF treatments were applied in the continuous flow mode, an inactivation rate of just 13% was achieved, after applying 80 pulses at 37.3 kV/cm and 3.5 Hz. The results of both heat and HIPEF treatments on enzyme inactivation were adjusted with good agreement to a first-order kinetic model (R2 > 62.3%).
Taste buds on the anterior part of the tongue develop in conjunction with epithelial-mesenchymal specializations in the form of gustatory (taste) papillae. Sonic hedgehog (Shh) and Bone Morphogenetic Protein 4 (BMP4) are expressed in developing taste papillae, but the roles of these signaling molecules in specification of taste bud progenitors and in papillary morphogenesis are unclear. We show here that BMP4 is not expressed in the early tongue, but is precisely coexpressed with Shh in papillary placodes, which serve as a signaling center for both gustatory and papillary development. To elucidate the role of Shh, we used an in vitro model of mouse fungiform papillary development to determine the effects of two functional inhibitors of Shh signaling: anti-Shh (5E1) antibody and cyclopamine. Cultured E11.5 tongue explants express Shh and BMP4(LacZ) in a pattern similar to that of intact embryos, localizing to developing papillary placodes after 2 days in culture. Tongues cultured with 5E1 antibody continue to express these genes in papillary patterns but develop more papillae that are larger and closer together than in controls. Tongues cultured with cyclopamine have a dose-dependent expansion of Shh and BMP4(LacZ) expression domains. Both antibody-treated and cyclopamine-treated tongue explants also are smaller than controls. Taken together, these results suggest that, although Shh is not involved in the initial specification of papillary placodes, Shh does play two key roles during pmcry development: (1) as a morphogen that directs cells toward a nonpapillary fate, and (2) as a mitogen, causing expansion of the interplacodal epithelium and underlying mesenchyme.
OBJECTIVES: To examine the association between the speech and swallowing aspect of health-related quality of life (HRQOL) and selected clinical parameters, and particularly to determine those that are predictive of good outcomes at 1 year after surgery. DESIGN: Prospective questionnaire and clinical study. SETTING: Regional Maxillofacial Unit. PARTICIPANTS: A total of 278 consecutive patients undergoing primary surgery for squamous cell carcinoma between 1995 and 1999. HRQOL was assessed using the University of Washington Quality of Life questionnaire (UW-QOL) pre-surgery, and post-surgery at 6 months, 1 year and later (median 39 months). MAIN OUTCOME MEASURES: Presentation of results was mainly descriptive, involving percentages and mean scores. Association of clinico-demographic factors with tumour site, and with UW-QOL swallowing and speech after 12 months, was tested with Fisher's exact or chi-squared tests as appropriate and modelled using logistic regression methods. RESULTS: Univariate relationships were seen between speech and swallowing scores and with tumour size, T staging, radiotherapy, type of surgery (primary closure or free tissue transfer), tumour site, extent of resection of posterior tongue and soft palate, and UW-QOL taste and saliva scores. Multiple logistic regression showed that no radiotherapy (P<0.001) and primary surgical closure/laser surgery (P=0.003) were the main predictors of good swallowing, and primary surgical closure/laser surgery was the main predictor of good speech (P<0.001) at 1 year. CONCLUSIONS: A number of clinical parameters can influence the speech and swallowing aspect of quality of life in these patients and when feasible, primary closure results in a better outcome than free flap reconstruction.
Unconditioned suppression of feeding due to novelty (hyponeophagia) was studied in Wistar Kyoto (WKY), Lewis, Fischer 344, and Wistar rats. Fasted rats were given access to food either in home cages (controls) or to a single pellet fixed to the middle of a novel open field environment (experimental). The degree of feeding suppression was significantly greater in WKY rats compared to the other three strains. We suggest that this hyponeophagia resembles the reduced feeding frequently associated with behavioral depression, and that this behavior in WKY rats is another demonstration that this strain is very responsive to stressful stimulation and may serve as a useful animal model for depressive behavior.
Twenty-five odor-active compounds were quantified in hand-squeezed juices of Valencia late and Navel oranges using stable isotope dilution assays. Odor activity values (OAVs, ratio of the concentration to odor thresholds) based on odor thresholds in water were calculated for the entire set of aroma compounds in both varieties. It was shown that due to their high OAVs, the fruity-smelling esters ethyl 2-methylpropanoate, ethyl butanoate, (S)-ethyl 2-methylbutanoate, and 3a,4,5,7a-tetrahydro-3,6-dimethyl-2(3H)-benzofuranone (wine lactone), the grassy smelling (Z)-hex-3-enal, and the citrus-like decanal were the most potent odorants in both juices. The weaker fruity note in the Navel oranges was clearly correlated with significantly lower OAVs of all fruity-smelling esters but a higher OAV of (Z)-3-hexenal compared to Valencia late. Model solutions simulating the odor of both orange varieties confirmed the findings of the quantitation studies.
Kynurenine (1) and indole-3-acetic acid (2) are considered as potential precursors of 2-aminoacetophenone (3), which is regarded to be the aroma impact compound causing an "untypical aging off-flavor" (UTA) in Vitis vinifera wines. The mechanism of the formation of 3 was studied using model fermentation and model sulfuration media spiked with 1 or 2 as potential precursors. Possible degradation products such as kynurenamine (4) and kynurenic acid (5), or skatole (6), 2-oxoskatole (7), 2-formamidoacetophenone (8), 2-oxindole-3-acetic acid (9), and 3-(2-formylaminophenyl)-3-oxopropionic acid (10) were evaluated by HPLC-UV of the fermentation and sulfuration media and comparison with synthesized 7, 8, 9, and 10. The synthesis of the possible precursor 4-(2-aminophenyl)-2,4-dioxobutanoic acid (11), a proposed metabolite of 1 failed because a spontaneous cyclization yields 5 and N-oxo-kynurenic acid (12), but not 11. It could be shown that the formation of 3 is triggered by an oxidative degradation of 2 after sulfuration with potassium bisulfite via the intermediates 10 and 8. However, no formation of 3 occurred during sulfuration of a model wine spiked with 1 or during fermentation of a model must spiked with 1 or 2.
The effect of the addition of sucrose to an ethanol solution upon daily intake patterns was examined in a continuous-access operant situation with Wistar rats. Rats were first initiated to self-administer orally a 10% ethanol (v/v) solution using the sucrose-substitution procedure in 30-min limited-access conditions. When then studied in a continuous-access operant situation (23 hr ethanol access), substantial increases in ethanol consumption were found when varying concentrations of sucrose were added to the ethanol solutions presented. This increased consumption was found to be a complex function of both an increase in the number of drinking occurrences each day and in the size of each drinking occurrence. When 2% sucrose was compared with 2% sucrose/10% ethanol, the consumption of the sweetened ethanol was greater than consumption of the sweetener alone, suggesting that the ethanol added to the ability of the solution to maintain behavior beyond that of the sucrose alone. This study supports the use of sweetened ethanol solutions for the study of ethanol drinking patterns, and as a model system for examining factors involved in the regulation of ethanol consumption.
It is surprising to note the evolution of success rates in Belgian universities especially in the first Year. Men are less successful than women and the differences are escalating in an alarming way. Dropouts take the same direction and women now represent a majority of the students at the university. In a previous study, we assessed 616 students in the first Year at the university of Liège with Vasev, the English name of which was TASTE, a self report questionnaire constituted of 4 factors: anxiety, self confidence, procrastination and performance value; anxiety particularly concerned somatic expression of students before and during test evaluations; self confidence was a cognitive component close to self efficacy; procrastination was the behavioral component characterizing avoidance when students are confronted with the risk of failure; performance value referred to intrinsic and extrinsic motivations. French validation of TASTE led to an abbreviated version of 50 items (THEE) consisting of 5 factors, the four of TASTE and an additional one, very consistent, at first called depression because of its correlations with this dimension, then called sense of competence on account of its semantic content. Self-competence has been described in the literature of Achievement Motivation and corresponded to expectancy and ability beliefs in performance process which was also relevant to self-efficacy except the particularity of comparison with others, which was not included in the last construct. Self-competence has been considered as an important part of the Worry component of test anxiety. Some Authors didn't hesitate to view causality flowing from self-competence to test anxiety and have conceptualized the latter as a failure of the self where one's sense of competence has been undermined as a result of experienced failure. In our study, only that factor was equally scored in women and men whereas it was scored higher in failed students. In other respects anxiety and performance value were scored higher in women, self-confidence and procrastination higher in men. Because TASTE didn't discriminate the different components of motivation (performance value referred to intrinsic and extrinsic motivations without precise distinction) we decided to use the MPS (Multidimensional Perfectionism Scale) which gave the opportunity to distinguish SOP (Self Oriented Perfectionism) ie, the self-imposed unrealistic standards with inability to accept faults in order to know and master a subject, that corresponded to intrinsic motivation; SPP (Socially Prescribed Perfectionism) ie, the exaggerated expectancies of others which are subjectively believed as imposed and uncontrollable leading to anxiety, feelings of failure or helplessness, that corresponded to extrinsic motivation; POO (Perfectionism Oriented to Others) ie, the unrealistic demands expected from significant others, which especially characterized males. We assumed that women attached more importance to succeed and submitted more to society exigencies. That way extrinsic and intrinsic motivations were probably more combined unlike men who, dreading a loss of self esteem, tried to avoid failure responsibility in using self handicapping or aggressive behaviours, so separating motivation in an extrinsic part turned to performance value and an intrinsic one more concerned by self confidence and sense of competence with the result that the motivational balance was surely disrupted in case of high competition leading to failure or avoidance. In another previous study we established a structural model illustrating, according to gender, correlations between anxiety, sense of incompetence, self-oriented perfectionism and socially prescribed perfectionism. Self-oriented perfectionism was less correlated to socially prescribed perfectionism in boys than in girls; furthermore especially by those who had never failed, it was negatively correlated to sense of incompetence, thus leading to lower scores of anxiety while in girls, by contrast, such a correlation didn't exist, thus involving higher anxiety. That way, on the one hand, intrinsic and extrinsic motivations by female students complementarily operated on the sense of incompetence and consequently on anxiety, the emotional component of test anxiety; on the other hand, by male students, intrinsic motivation had a negative correlation with the sense of incompetence and a lower correlation with extrinsic motivation, thereby shedding some light on the problem of anxiety level differences according to gender. More, that observation corresponded well to the model of self-worth where test anxiety was understood as a manifestation of perceived incompetence and as a defensive way to ward off negative self-evaluation; that model suited particularly well to boys and explained their attempts to maintain self-worth when risking academic failure. The present research assumes that independence or combination of motivation components is also correlated to different expressions of aggressiveness: hostility corresponding to threat and characterizing more girls while physical aggression is corresponding to personal challenge, a more masculine attribution. If fighting against the sense of incompetence actually characterizes men and consequently shows too the competitive aspects of performance strong enough to mobilize intrinsic motivation, what would be expected regarding the notion of threat suspected to be predominant in girls? The idea of using a questionnaire discriminating the specific dimensions of aggressiveness in fact the Aggression Questionnaire should meet the following purposes: At first establish a French version of that aggression questionnaire, perform the factorial analyses and internal consistency, compare them with other previous samples, then differentiate gender in general and in failure versus success situations. Finally include the different components of aggressiveness in the first described model and build a new one liable to define in boys the explicit pathways between test anxiety, perfectionism and aggressiveness. Statistical analyses have confirmed, in a 3 factor solution, the presence of emotional (anger), cognitive (hostility) and behavioural (physical aggression) components. Internal consistency is satisfactory. It is demonstrated that physical aggression characterizes boys (F=12.04, p=0.0001) while hostility (F=5.22, p=0.0015) and anger (F=0.49, p=0.0001) characterizes girls; furthermore it is noted that physical aggression characterizes more failed students (F=13.43, p=0.0003). Four models (see figures 2, 3, 4, 5) have been established, at first focused on the distinction of correlations between motivation and cognitive and emotional components on the samples of boys (n=268) and girls (348), then developed on the samples of successful students, male (n=193) and female (n=271). They describe the differentiated action of intrinsic and extrinsic motivations on the different components of aggressiveness and test-anxiety according to gender and without experience of failure. The dynamic process of the organizational factors is different according to gender and psychopathology resulting from the combinations of behaviors, cognitions and emotions would be assumed, prioritizing physical aggression and psychopathy by boys, anxiety and depression by girls. Anyway more explanation about the evolution of success rates of boys and girls in Belgian universities is proposed.
The purpose of this study was to identify sites where striatopallidal lesions produce two distinct sensory-triggered hyperkinetic syndromes: (1) exaggerated forelimb treading alone to oral taste infusions and (2) sensorimotor exaggerated treading plus enhanced aversive reactions to taste infusions. The behavioral characteristics of these syndromes have been described previously (Berridge, K.C. and Cromwell, H.C., Behav. Neurosci., 104 (1990) 778-795). Bilateral excitotoxin lesions were made using quinolinic acid (10 micrograms in 1 microliter) in the caudate/putamen, nucleus accumbens, globus pallidus or ventral pallidum/substantia innominata. In order to identify the precise center, borders, severity and size of lesion sites that caused these hyperkinetic treading syndromes, neuron counts (modified fractionator technique) and glial fibrillary acidic protein immunoreactivity (GFAP-IR) densitometry were used in a stereological mapping analysis. The site of lesions that produced the hyperkinetic treading syndrome without enhanced aversion was found to be restricted to the globus pallidus (GP). Damage exceeding 60% neuron loss bilaterally within a 0.8 x 1.0 x 1.0 mm subregion of the ventromedial GP produced this syndrome. The site of lesions that produced the combined syndrome of hyperkinetic treading and aversive enhancement was ventral to the globus pallidus, within the ventral pallidum/substantia innominata (VP/SI). Damage exceeding 70% neuron loss bilaterally within a 1.0 x 0.5 x 1.0 mm diameter subregion of the ventromedial ventral pallidum/substantia innominata produced this syndrome. This subterritory was located immediately lateral to the border of the lateral hypothalamus. Bilateral lesions to the caudate/putamen or nucleus accumbens did not produce either hyperkinetic treading syndrome. These results are discussed in terms of the connectivity of the ventral pallidal/substantia innominata and globus pallidus regions and in terms of neuropathological models of hyperkinetic disorders.
OBJECTIVE: To identify predictors of healthful dietary practices in adolescents using the Theory of Planned Behavior and determine how gender and ethnicity influence the relationship among the theoretical constructs. DESIGN: Initial and 1-month follow-up questionnaires, designed to measure the constructs of the Theory of Planned Behavior and select demographic items, were administered to the participants in the spring of 1997 to gather data for this descriptive research. SETTINGS/PARTICIPANTS: A sample of 780 adolescents, aged 14 to 19 years, was recruited from randomly selected science classes at 4 public high schools in San Bernardino, California. Seven hundred and fifty participants (96%) completed the initial questionnaire and 672 (86%) completed the follow-up questionnaire. ANALYSIS: A 5-step hierarchical multiple regression procedure, general linear model analysis, and Tukey's honestly significant difference post hoc test were used to analyze the data. RESULTS: Intention to eat a healthful diet was a predictor of healthful dietary behavior. Intention was influenced most by attitude and then by perceived behavioral control and subjective norm. Those with positive attitudes toward healthful eating believed that they would like the taste of healthful foods, feel good about themselves, tolerate giving up foods that they like to eat, and lose weight or maintain a healthful weight. Mother, siblings, and friends were identified as important predictors of subjective norm. Knowledge about how to eat a healthful diet, availability of healthful foods, motivation, and access to enough money were salient facilitating factors related to perceived behavioral control. Interesting contrasts among gender and ethnic groups also were noted. CONCLUSIONS AND IMPLICATIONS: The findings indicate that multiple attitudinal, normative, and control factors influence healthful dietary behavior in adolescents. The synergistic use of these factors in the development and implementation of nutrition education interventions may assist in the promotion of healthful eating among teens from culturally diverse communities.
OBJECTIVE: To determine factors associated with the consumption of fruit and vegetables among 11-year-old schoolchildren in Belgium-Flanders and the Netherlands. DESIGN: In total, 2468 school children from 98 randomly selected schools participated in a cross-sectional survey. VARIABLES MEASURED: Frequency of fruit and vegetable intake and potential personal, social and environmental correlates were measured by means of self-administered, school-based, written questionnaires. ANALYSIS: Hierarchical multiple regression analyses were conducted to assess potential correlates of schoolchildren's fruit and vegetable consumption. Separate analyses were conducted for boys and girls. RESULTS: Bringing fruit to school, modeling behavior of parents and friends, parents demanding that their child eat fruit, knowledge about recommended intake levels, liking fruit, and self-efficacy to eat fruit were the strongest correlates of fruit intake. For vegetables, gender, parental demand, parents facilitating the consumption of vegetables by cutting them for their child, modeling behavior of parents and friends, and preferences for vegetables emerged as strongest correlates. No substantial differences in significant correlates were found according to gender. The percentage of explained variance was 33.7% for fruit and 28.4% for vegetable intake. CONCLUSIONS: Interventions need to be focused on personal (taste preferences), social (parental influences), and environmental factors (availability).