scholarly journals Whole-Brain Mapping of the Expression Pattern of T1R2, a Subunit Specific to the Sweet Taste Receptor

2021 ◽  
Vol 15 ◽  
Author(s):  
Jea Hwa Jang ◽  
Ha Kyeong Kim ◽  
Dong Woo Seo ◽  
Su Young Ki ◽  
Soonhong Park ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Metabolic Regulation ◽  
Taste Receptor ◽  
Sweet Taste ◽  
Taste Receptors ◽  
Sweet Taste Receptor ◽  
Sweet Taste Receptors ◽  
The Central Nervous System ◽  
A Subunit ◽  
The Brain

Chemosensory receptors are expressed primarily in sensory organs, but their expression elsewhere can permit ligand detection in other contexts that contribute to survival. The ability of sweet taste receptors to detect natural sugars, sugar alcohols, and artificial sweeteners suggests sweet taste receptors are involved in metabolic regulation in both peripheral organs and in the central nervous system. Our limited knowledge of sweet taste receptor expression in the brain, however, has made it difficult to assess their contribution to metabolic regulation. We, therefore, decided to profile the expression pattern of T1R2, a subunit specific to the sweet taste receptor complex, at the whole-brain level. Using T1r2-Cre knock-in mice, we visualized the overall distribution of Cre-labeled cells in the brain. T1r2-Cre is expressed not only in various populations of neurons, but also in glial populations in the circumventricular organs and in vascular structures in the cortex, thalamus, and striatum. Using immunohistochemistry, we found that T1r2 is expressed in hypothalamic neurons expressing neuropeptide Y and proopiomelanocortin in arcuate nucleus. It is also co-expressed with a canonical taste signaling molecule in perivascular cells of the median eminence. Our findings indicate that sweet taste receptors have unidentified functions in the brain and suggest that they may be a novel therapeutic target in the central nervous system.

scholarly journals Sweet Taste Receptor Signaling Network: Possible Implication for Cognitive Functioning

2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
Menizibeya O. Welcome ◽  
Nikos E. Mastorakis ◽  
Vladimir A. Pereverzev
Keyword(s):  
Cognitive Functioning ◽  
Transmembrane Protein ◽  
Taste Receptor ◽  
Sweet Taste ◽  
The Body ◽  
Taste Receptors ◽  
Receptor Signaling ◽  
Sweet Taste Receptor ◽  
Sweet Taste Receptors

Sweet taste receptors are transmembrane protein network specialized in the transmission of information from special “sweet” molecules into the intracellular domain. These receptors can sense the taste of a range of molecules and transmit the information downstream to several acceptors, modulate cell specific functions and metabolism, and mediate cell-to-cell coupling through paracrine mechanism. Recent reports indicate that sweet taste receptors are widely distributed in the body and serves specific function relative to their localization. Due to their pleiotropic signaling properties and multisubstrate ligand affinity, sweet taste receptors are able to cooperatively bind multiple substances and mediate signaling by other receptors. Based on increasing evidence about the role of these receptors in the initiation and control of absorption and metabolism, and the pivotal role of metabolic (glucose) regulation in the central nervous system functioning, we propose a possible implication of sweet taste receptor signaling in modulating cognitive functioning.

scholarly journals Drosophila sweet taste receptor

2002 ◽  
Vol 74 (7) ◽  
pp. 1159-1165 ◽  
Author(s):  
Kunio Isono ◽  
Kohei Ueno ◽  
Masayuki Ohta ◽  
Hiromi Morita
Keyword(s):  
Taste Receptor ◽  
Sweet Taste ◽  
P Element ◽  
Taste Receptors ◽  
Wild Populations ◽  
Intracellular Loop ◽  
Sweet Taste Receptor ◽  
Loop Domain ◽  
Sweet Taste Receptors ◽  
Receptor Family

Like the Sac locus controlling sugar sensitivity in mice, the taste gene Tre of the fruitfly Drosophila was discovered in wild populations as a genetic dimorphism controlling gustatory sensitivity to a sugar trehalose. By activating a P-element transposon near the gene locus we obtained induced Tre mutations and analyzed the associated changes in gene organizations and the mRNA expressions. The analysis showed that Tre is identical to Gr5a, a gene that belongs to a novel seven-transmembrane receptor family expressed in chemosensory neurons and predicted to encode chemosensory receptors. Thus, Gr5a is a candidate sweet taste receptor in the fly. An amino acid substitution in the second intracellular loop domain was identified to be functionally correlated with the genetic dimorphism of Tre. Since Tre controls sweet taste sensitivity to a limited subset of sugars, other Gr genes phylogenetically related to Tre may also encode sweet taste receptors. Those candidate sweet taste receptors, however, are phylogenetically distinct from vertebrate sweet taste receptors, suggesting that the sweet taste receptors in animals do not share a common origin.

scholarly journals Taste sensations: history of study, evolutionary feasibility and strategies for forming correct taste preferences in children

2020 ◽  
pp. 65-73
Author(s):  
I. N. Zakharova ◽  
Yu. A. Dmitrieva ◽  
E. B. Machneva ◽  
A. N. Tsutsaeva
Keyword(s):  
Eating Disorders ◽  
Human Health ◽  
Taste Receptor ◽  
Sweet Taste ◽  
Food Selectivity ◽  
Taste Preferences ◽  
Taste Receptors ◽  
Sweet Taste Receptor ◽  
Sweet Taste Receptors ◽  
History Of

Taste preferences influence not only the formation of human health, but also many areas of his life. That is why the problem of understanding the nature and regularities of taste formation has been a concern for scientists since ancient times and remains relevant nowadays. The article presents generalized data on the history of studying taste from the times of Ancient Greece to our time. Notions about the system of taste sensations in works of Aristotle, Galen, Avicenna, Vesaliy, other medieval scientists and researchers of New time are described. The authors also present an overview of current studies on the evolutionary appropriateness of taste sensations using the expression of sweet taste receptors in animals with different diets. It has been shown that obligate carnivorous animals have lost the function of sweet taste receptors, and in hummingbirds eating sweet floral nectar, on the contrary, another sweet taste receptor has acquired the function of a sweet taste receptor to detect sugars. The authors pay special attention to the available ways of forming correct taste preferences and overcoming eating disorders in infants, which is important from the point of view of the child’s future health. In particular, strategies for repeated taste effects of new foods as well as multisensory interactions with food, including sound, visual, olfactory, tactile and tasting effects are presented. It is particularly important to develop correct taste habits in children with eating disorders such as neophobia and food selectivity. Understanding the multifactorial nature of taste preferences and their impact on human health allows finding new strategies to «teach» taste from early childhood.

scholarly journals Loss of sweet taste despite the conservation of sweet receptor genes in insectivorous bats

2021 ◽  
Vol 118 (4) ◽  
pp. e2021516118
Author(s):  
Hengwu Jiao ◽  
Huan-Wang Xie ◽  
Libiao Zhang ◽  
Nima Zhuoma ◽  
Peihua Jiang ◽  
...  
Keyword(s):  
Functional Divergence ◽  
Receptor Gene ◽  
Taste Receptor ◽  
Sweet Taste ◽  
Taste Perception ◽  
Taste Receptors ◽  
Behavioral Experiments ◽  
Insectivorous Bats ◽  
Sweet Taste Receptor ◽  
Sweet Taste Receptors

The evolution of taste perception is usually associated with the ecology and dietary changes of organisms. However, the association between feeding ecology and taste receptor evolution is unclear in some lineages of vertebrate animals. One example is the sweet taste receptor gene Tas1r2. Previous analysis of partial sequences has revealed that Tas1r2 has undergone equally strong purifying selection between insectivorous and frugivorous bats. To test whether the sweet taste function is also important in bats with contrasting diets, we examined the complete coding sequences of both sweet taste receptor genes (Tas1r2 and Tas1r3) in 34 representative bat species. Although these two genes are highly conserved between frugivorous and insectivorous bats at the sequence level, our behavioral experiments revealed that an insectivorous bat (Myotis ricketti) showed no preference for natural sugars, whereas the frugivorous species (Rousettus leschenaultii) showed strong preferences for sucrose and fructose. Furthermore, while both sweet taste receptor genes are expressed in the taste tissue of insectivorous and frugivorous bats, our cell-based assays revealed striking functional divergence: the sweet taste receptors of frugivorous bats are able to respond to natural sugars whereas those of insectivorous bats are not, which is consistent with the behavioral preference tests, suggesting that functional evolution of sweet taste receptors is closely related to diet. This comprehensive study suggests that using sequence conservation alone could be misleading in inferring protein and physiological function and highlights the power of combining behavioral experiments, expression analysis, and functional assays in molecular evolutionary studies.

scholarly journals The effects of sweeteners and sweetness enhancers on obesity and diabetes: a review

2018 ◽  
Vol 4 ◽  
Author(s):  
Yanli Jiao ◽  
Yu Wang
Keyword(s):  
Metabolic Regulation ◽  
Hormone Secretion ◽  
Taste Receptor ◽  
Caloric Intake ◽  
Sweet Taste ◽  
The Body ◽  
Incretin Hormone ◽  
Obesity And Diabetes ◽  
Sweet Taste Receptors

Sweet taste, one of the five basic taste qualities, is not only important for evaluation of food quality, but also guides the dietary food choices of animals. Sweet taste involves a variety of chemical compounds and structures, including natural sugars, sugar alcohols, natural and artificial sweeteners, and sweet-tasting proteins. The preference for sweetness has induced the over-consumption of sugar, contributing to certain prevailing health problems, such as obesity, diabetes and cardiovascular disease. Non-nutritive sweeteners, including natural and synthetic sweeteners, and sweet-tasting proteins have been added to foods to reduce the caloric intake from sugar, but many of these sugar substitutes induce an off-taste or after taste that negatively impacts any pleasure derived from the sweet taste. Sweet taste is detected by sweet taste receptor, that also play an important role in the metabolic regulation of the body, such as glucose homeostasis and incretin hormone secretion. In this review, the role of sweet tastants and the sweet taste receptors involved in sweetness perception, and their effect on obesity and diabetes are summarized. Sweet taste enhancement, as a new way to solve the over-consumption of sugar, is discussed in this contribution. Sweet taste enhancers can bind with sweet tastans to potentiate the sweetness of food without producing any taste by itself. Various type of sweet taste enhancers, including synthetic compounds, food-processed substances and aroma compounds, are summarized. Notably, few natural, non-volatile compounds have been identified as sweetness enhancers.

scholarly journals Genetics of sweet taste preferences

2002 ◽  
Vol 74 (7) ◽  
pp. 1135-1140 ◽  
Author(s):  
Alexander A. Bachmanov ◽  
Danielle R. Reed ◽  
Xia Li ◽  
Gary K. Beauchamp
Keyword(s):  
Positional Cloning ◽  
Inbred Mouse ◽  
Taste Receptor ◽  
Sweet Taste ◽  
Mouse Strains ◽  
Taste Receptors ◽  
Chromosome 4 ◽  
Sweet Taste Receptor ◽  
Distal Chromosome ◽  
Allelic Differences

Inbred mouse strains display marked differences in avidity for sweet solutions due in part to genetic differences among strains. Using several techniques, we have located a number of regions throughout the genome that influence sweetener acceptance. One prominent locus regulating differences in sweetener preferences among mouse strains is the saccharin preference (Sac) locus on distal chromosome 4. Afferent responses of gustatory nerves to sweeteners also vary as a function of allelic differences in the Sac locus, suggesting that this gene may encode a sweet taste receptor. Using a positional cloning approach, we identified a gene (Tas1r3) encoding the third member of the T1R family of putative taste receptors, T1R3. Introgression by serial back-crossing of a chromosomal fragment containing the Tas1r3 allele from the high sweetener-preferring strain onto the genetic background of the low sweetener-preferring strain rescued its low sweetener-preference phenotype. Tas1r3 has two common haplotypes, one found in mouse strains with elevated sweetener preference and the other in strains relatively indifferent to sweeteners. This study, in conjunction with complimentary recent studies from other laboratories, provides compelling evidence that Tas1r3 is equivalent to the Sac locus and that the T1R3 receptor (when co-expressed with taste receptor T1R2) responds to sweeteners. However, other sweetness receptors may remain to be identified.

scholarly journals Sweet Taste Is Complex: Signaling Cascades and Circuits Involved in Sweet Sensation

2021 ◽  
Vol 15 ◽  
Author(s):  
Elena von Molitor ◽  
Katja Riedel ◽  
Michael Krohn ◽  
Mathias Hafner ◽  
Rüdiger Rudolf ◽  
...  
Keyword(s):  
Alternative Pathway ◽  
Taste Receptor ◽  
Physiological Role ◽  
Primary Source ◽  
Sweet Taste ◽  
Receptor Expression ◽  
Taste Bud ◽  
Sweet Taste Receptor ◽  
The Brain ◽  
Taste Bud Cells

Sweetness is the preferred taste of humans and many animals, likely because sugars are a primary source of energy. In many mammals, sweet compounds are sensed in the tongue by the gustatory organ, the taste buds. Here, a group of taste bud cells expresses a canonical sweet taste receptor, whose activation induces Ca2+ rise, cell depolarization and ATP release to communicate with afferent gustatory nerves. The discovery of the sweet taste receptor, 20 years ago, was a milestone in the understanding of sweet signal transduction and is described here from a historical perspective. Our review briefly summarizes the major findings of the canonical sweet taste pathway, and then focuses on molecular details, about the related downstream signaling, that are still elusive or have been neglected. In this context, we discuss evidence supporting the existence of an alternative pathway, independent of the sweet taste receptor, to sense sugars and its proposed role in glucose homeostasis. Further, given that sweet taste receptor expression has been reported in many other organs, the physiological role of these extraoral receptors is addressed. Finally, and along these lines, we expand on the multiple direct and indirect effects of sugars on the brain. In summary, the review tries to stimulate a comprehensive understanding of how sweet compounds signal to the brain upon taste bud cells activation, and how this gustatory process is integrated with gastro-intestinal sugar sensing to create a hedonic and metabolic representation of sugars, which finally drives our behavior. Understanding of this is indeed a crucial step in developing new strategies to prevent obesity and associated diseases.

scholarly journals Sweet-taste receptors, low-energy sweeteners, glucose absorption and insulin release

2010 ◽  
Vol 104 (10) ◽  
pp. 1415-1420 ◽  
Author(s):  
Andrew G. Renwick ◽  
Samuel V. Molinary
Keyword(s):  
Insulin Release ◽  
Taste Receptor ◽  
Sweet Taste ◽  
Glucose Absorption ◽  
Enteroendocrine Cells ◽  
Low Energy ◽  
Taste Receptors ◽  
Sweet Taste Receptors

The present review explores the interactions between sweeteners and enteroendocrine cells, and consequences for glucose absorption and insulin release. A combination of in vitro,in situ, molecular biology and clinical studies has formed the basis of our knowledge about the taste receptor proteins in the glucose-sensing enteroendocrine cells and the secretion of incretins by these cells. Low-energy (intense) sweeteners have been used as tools to define the role of intestinal sweet-taste receptors in glucose absorption. Recent studies using animal and human cell lines and knockout mice have shown that low-energy sweeteners can stimulate intestinal enteroendocrine cells to release glucagon-like peptide-1 and glucose-dependent insulinotropic peptide. These studies have given rise to major speculations that the ingestion of food and beverages containing low-energy sweeteners may act via these intestinal mechanisms to increase obesity and the metabolic syndrome due to a loss of equilibrium between taste receptor activation, nutrient assimilation and appetite. However, data from numerous publications on the effects of low-energy sweeteners on appetite, insulin and glucose levels, food intake and body weight have shown that there is no consistent evidence that low-energy sweeteners increase appetite or subsequent food intake, cause insulin release or affect blood pressure in normal subjects. Thus, the data from extensive in vivo studies in human subjects show that low-energy sweeteners do not have any of the adverse effects predicted by in vitro,in situ or knockout studies in animals.

scholarly journals Expansion of sweet taste receptor genes in grass carp (Ctenopharyngodon idellus) coincided with vegetarian adaptation

2019 ◽  
Author(s):  
Xiao-Chen Yuan ◽  
Xu-Fang Liang ◽  
Wen-Jing Cai ◽  
Shan He ◽  
Wen-Jie Guo ◽  
...  
Keyword(s):  
Gene Expression ◽  
Grass Carp ◽  
Genetic Basis ◽  
Taste Receptor ◽  
Food Habit ◽  
Adaptive Strategy ◽  
Sweet Taste ◽  
Sweet Taste Receptor ◽  
Intracellular Calcium Signaling ◽  
Sweet Taste Receptors

Abstract Background Taste is fundamental to diet selection in vertebrates. Genetic basis of sweet taste receptor in the shaping of food habits has been extensively studied in mammals and birds, but scarcely studied in fishes. Grass carp is an excellent model for studying vegetarian adaptation, as it exhibits food habit transition from carnivory to herbivory. Results We identified six sweet taste receptors (gcT1R2A-F) in grass carp. The four gcT1R2s (gcT1R2C-F) have been suggested to be evolved from and paralogous to the two original gcT1R2s (gcT1R2A and gcT1R2B). All gcT1R2s were expressed in taste organs and mediated glucose- or fructose-induced intracellular calcium signaling, revealing they were functional. Cells co-transfected with six gcT1R2s/gcT1R3 showed a greater response to glucose or fructose than those transfected alone, while a lower response to plant specific fructose than those co-transfected with the new four gcT1R2s/gcT1R3. Moreover, food habit transition from carnivory to herbivory in grass carp was accompanied by increased gene expression of certain gcT1R2s. Conclusions We suggested that the gene expansion of T1R2 in grass carp was an adaptive strategy to accommodate the change in food environment. Moreover, the selected gene expression of gcT1R2s might drive the food habit transition from carnivory to herbivory in grass carp. This study provided some evolutional and physiological clues for the formation of herbivory in grass carp.

scholarly journals The preference for sugar over sweetener depends on a gut sensor cell

2022 ◽  
Author(s):  
Kelly L. Buchanan ◽  
Laura E. Rupprecht ◽  
M. Maya Kaelberer ◽  
Atharva Sahasrabudhe ◽  
Marguerita E. Klein ◽  
...  
Keyword(s):  
Vagus Nerve ◽  
Sweet Taste ◽  
Taste Receptors ◽  
Neural Pathways ◽  
Glutamatergic Neurotransmission ◽  
Sensory Cues ◽  
Sweet Taste Receptors ◽  
Sensor Cell ◽  
Glutamatergic Signaling ◽  
The Brain

AbstractGuided by gut sensory cues, humans and animals prefer nutritive sugars over non-caloric sweeteners, but how the gut steers such preferences remains unknown. In the intestine, neuropod cells synapse with vagal neurons to convey sugar stimuli to the brain within seconds. Here, we found that cholecystokinin (CCK)-labeled duodenal neuropod cells differentiate and transduce luminal stimuli from sweeteners and sugars to the vagus nerve using sweet taste receptors and sodium glucose transporters. The two stimulus types elicited distinct neural pathways: while sweetener stimulated purinergic neurotransmission, sugar stimulated glutamatergic neurotransmission. To probe the contribution of these cells to behavior, we developed optogenetics for the gut lumen by engineering a flexible fiberoptic. We showed that preference for sugar over sweetener in mice depends on neuropod cell glutamatergic signaling. By swiftly discerning the precise identity of nutrient stimuli, gut neuropod cells serve as the entry point to guide nutritive choices.

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