1,721,009 research outputs found
Effect of the rs2821557 Polymorphism of the Human Kv1.3 Gene on Olfactory Function and BMI in Different Age Groups
Full text linkThe sense of smell plays an important role in influencing the eating habits of individuals and consequently, their body weight, and its impairment has been associated with modified eating behaviors and malnutrition problems. The inter-individual variability of olfactory function depends on several factors, including genetic and physiological ones. In this study, we evaluated the role of the Kv1.3 channel genotype and age, as well as their mutual relationships, on the olfactory function and BMI of individuals divided into young, adult and elderly groups. We assessed olfactory performance in 112 healthy individuals (young n = 39, adult n = 36, elderly n = 37) based on their TDI olfactory score obtained through the Sniffin' Sticks test and their BMI. Participants were genotyped for the rs2821557 polymorphism of the human gene encoding Kv1.3 channels, the minor C allele of which was associated with a decreased sense of smell and higher BMIs compared to the major T allele. The results show that TT homozygous subjects obtained higher TDI olfactory scores and showed lower BMIs than CC homozygous subjects, in all age groups considered. Furthermore, the positive effect of the T allele on olfactory function and BMI decreased with increasing age. The contribution of the genetic factor is less evident with advancing age, while the importance of the age factor is compensated for by genetics. These results show that genetic and physiological factors such as age act to balance each other
The Implications of Taste and Olfaction in Nutrition and Health
Full text linkTaste and olfaction are sensory modalities that act synergistically to orchestrate the behaviors essential for survival, such as interactions with the environment, nutrient-rich food identification, and the avoidance of noxious substances [...]
Effect of oral supplementation of L-Arginine at increasing concentrations on PROP bitter taste responsiveness
No full textTaste perception of sweet, sour, salty, bitter, and Umami and changes due to L-arginine supplementation, as a function of genetic ability to taste 6-n-propylthiouracil
Full text linkBehavioral reaction to different taste qualities affects nutritional status and health. 6-n-Propylthiouracil (PROP) tasting has been reported to be a marker of variation in taste perception, food preferences, and eating behavior, but results have been inconsistent. We showed that L-Arg can enhance the bitterness intensity of PROP, whilst others have demonstrated a suppression of the bitterness of quinine. Here, we analyze the taste perception of sweet, sour, salty, bitter, and umami and the modifications caused by L-Arg supplementation, as a function of PROP-taster status. Taste perception was assessed by testing the ability to recognize, and the responsiveness to, representative solutions of the five primary taste qualities, also when supplemented with L-Arg, in subjects classified as PROP-tasting. Super-tasters, who showed high papilla density, gave higher ratings to sucrose, citric acid, caffeine, and monosodium L-glutamate than non-tasters. L-Arg supplementation mainly modified sucrose perception, enhanced the umami taste, increased NaCl saltiness and caffeine bitterness only in tasters, and decreased citric acid sourness. Our findings confirm the role of PROP phenotype in the taste perception of sweet, sour, and bitter and show its role in umami. The results suggest that L-Arg could be used as a strategic tool to specifically modify taste responses related to eating behaviors
Olfactory Sensitivity Is Associated with Body Mass Index and Polymorphism in the Voltage-Gated Potassium Channels Kv1.3
Full text linkSmell strongly contributes to food choice and its hedonistic evaluation. A reduction or loss of smell has been related to malnutrition problems, resulting in excessive weight loss or gain. Voltage-gated potassium channels Kv1.3 are widely expressed in the olfactory bulb, and contribute mainly to the value of the resting membrane potential and to the frequency of action potentials. Mutations in the Kv1.3 gene are associated with alterations in glycemic homeostasis and olfactory sensitivity. We evaluated the olfactory performance in 102 healthy subjects and its association with BMI and polymorphism in the human Kv1.3 gene. Olfactory performance, based on the olfactory threshold, discrimination and identification scores and their summed score (TDI), was measured using the “Sniffin’ Sticks” test. Subjects were genotyped for the rs2821557 polymorphism of the Kv1.3 gene, whose major allele T was associated with a super-smeller phenotype, lower plasma glucose levels and resistance to diet-induced obesity as compared with the minor allele C. Based on the Kv1.3 genotype, the TDI and I olfactory scores obtained by the subjects were the following: TT > TC > CC. Subjects who were TT homozygous or heterozygous exhibited lower BMIs and reached higher olfactory scores than those with the CC genotype. The results were sex-dependent: heterozygous females performed better than heterozygous males. These findings show an inverse relationship between olfactory function and BMI, and a significant effect of the Kv1.3 genotypes on the olfactory functions and on the BMIs of the subjects. Finally, they suggest that the sex-related differences in the olfactory function can be partially ascribed to the Kv1.3 gene’s polymorphism
Sensing with the legs: contribution of pereiopods in the detection of food-related compounds in the red swamp crayfish Procambarus clarkii
No full textThe red swamp crayfish Procambarus clarkii (Girard, 1852) is one of the most hazardous invasive alien species of freshwater habitats.
Like other decapod crustaceans, crayfish rely on chemical senses to detect and localize food resources. By way of extracellular nerve recordings coupled with behavioural bioassays, we investigated the sensitivity spectra of the walking leg chemoreceptors of P. clarkii in response to different food-related compounds. Recordings from isolated legs confirmed a marked sensitivity of the legs to trehalose, cellobiose, sucrose, maltose, glycine, and leucine. Some sensitivity to glucose, fructose, asparagine, and taurocholic acid was also found.
Under confined experimental conditions, the behavioural bioassays excluded involvement of antennules in the detection of food-related compounds, thus emphasizing the role of the legs as the main short-distance, broad-spectrum sensors involved in feeding. Such information could be valuable for the identification of key chemicals aimed at the future development of strategies for crayfish population control programs
Electrophysiological recordings from the tongue for the objective evaluation of individual variations of 6-n-propylthiouracil (PROP) sensitivity
No full textSeveral studies have focused on identifying the factors that lead to divergent conclusions about the role of the PROP phenotype in taste perception, food preferences, and nutrition. One of the major issues is the difficulty in obtaining an objective measure of the taste phenotype. Here we present direct measures of the gustatory system activation, by electrophysiological recordings from the tongue, in thirty subjects classified by PROP taster status and genotyped for TAS2R38. The potentials generated by PROP stimulation were recorded by means of differential electrophysiological derivations between two silver electrodes, one in contact with the ventral surface of the tongue and one in perfect adhesion with the dorsal surface. The signals were recorded by a polygraph for human use and visualized in real time on PC. The electrotastegrams (ETGs) were analyzed by Clampfit 10.0 software and validated by comparing the voltage amplitude of signals with the perceived PROP bitterness intensity, PROP taster status and TAS2R38 genotypes. The ETGs showed that PROP stimulation evoked negative monophasic potentials characterized by a fast initial rise followed by a slow decline. These potentials represent the measure of the summated voltage change resulting from the response of stimulated taste cells. The amplitude of potentials was highly correlated with the perceived PROP bitterness intensity (p< 0.0001), with voltage reaching as high as 120 mV in super-taster who were homozygous for the tasting variant (PAV) of TAS2R38. The depolarization amplitude, as well as depolarization rate, were associated with PROP taster status and TAS2R38 diplotypes. The direct relationship between the potentials recorded and the parameters defining PROP phenotype show that ETG is a simple and reliable technology for the quantitative measure of the peripheral taste function, which may find application as an objective investigation tool in studies aimed at evaluating eating behavior and taste function impairment
Relationships between gustin (CA6) gene polymorphism, bitter taste sensitivity, fungiform papillae density and morphology
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A Supervised Learning Regression Method for the Analysis of the Taste Functions of Healthy Controls and Patients with Chemosensory Loss
Full text link: In healthy humans, taste sensitivity varies widely, influencing food selection and nutritional status. Chemosensory loss has been associated with numerous pathological disorders and pharmacological interventions. Reliable psychophysical methods are crucial for analyzing the taste function during routine clinical assessment. However, in the daily clinical routine, they are often considered too time-consuming. We used a supervised learning (SL) regression method to analyze with high precision the overall taste statuses of healthy controls (HCs) and patients with chemosensory loss, and to characterize the combination of responses that would best predict the overall taste statuses of the subjects in the two groups. The random forest regressor model allowed us to achieve our objective. The analysis of the order of importance of each parameter and their impact on the prediction of the overall taste statuses of the subjects in the two groups showed that salty (low-concentration) and sour (high-concentration) stimuli specifically characterized healthy subjects, while bitter (high-concentration) and astringent (high-concentration) stimuli identified patients with chemosensory loss. Although the present results require confirmation in studies with larger samples, the identification of such distinctions should be of interest to the health system because they may justify the use of specific stimuli during the routine clinical assessments of taste function and thereby reduce time and cost commitments
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