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1.
Cells ; 11(15)2022 Aug 04.
Artigo em Inglês | MEDLINE | ID: mdl-35954259

RESUMO

Mucociliary clearance is a primary defence mechanism of the airways consisting of two components, ciliary beating and transepithelial ion transport (ISC). Specialised chemosensory cholinergic epithelial cells, named brush cells (BC), are involved in regulating various physiological and immunological processes. However, it remains unclear if BC influence ISC. In murine tracheae, denatonium, a taste receptor agonist, reduced basal ISC in a concentration-dependent manner (EC50 397 µM). The inhibition of bitter taste signalling components with gallein (Gßγ subunits), U73122 (phospholipase C), 2-APB (IP3-receptors) or with TPPO (Trpm5, transient receptor potential-melastatin 5 channel) reduced the denatonium effect. Supportively, the ISC was also diminished in Trpm5-/- mice. Mecamylamine (nicotinic acetylcholine receptor, nAChR, inhibitor) and amiloride (epithelial sodium channel, ENaC, antagonist) decreased the denatonium effect. Additionally, the inhibition of Gα subunits (pertussis toxin) reduced the denatonium effect, while an inhibition of phosphodiesterase (IBMX) increased and of adenylate cyclase (forskolin) reversed the denatonium effect. The cystic fibrosis transmembrane conductance regulator (CFTR) inhibitor CFTRinh172 and the KCNQ1 potassium channel antagonist chromanol 293B both reduced the denatonium effect. Thus, denatonium reduces ISC via the canonical bitter taste signalling cascade leading to the Trpm5-dependent nAChR-mediated inhibition of ENaC as well as Gα signalling leading to a reduction in cAMP-dependent ISC. Therefore, BC activation contributes to the regulation of fluid homeostasis.


Assuntos
Regulador de Condutância Transmembrana em Fibrose Cística , Papilas Gustativas , Animais , Camundongos , Compostos de Amônio Quaternário/farmacologia , Paladar/fisiologia
2.
PLoS Biol ; 20(7): e3001537, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35877759

RESUMO

Gustatory cortex (GC), a structure deeply involved in the making of consumption decisions, presumably performs this function by integrating information about taste, experiences, and internal states related to the animal's health, such as illness. Here, we investigated this assertion, examining whether illness is represented in GC activity, and how this representation impacts taste responses and behavior. We recorded GC single-neuron activity and local field potentials (LFPs) from healthy rats and rats made ill (via LiCl injection). We show (consistent with the extant literature) that the onset of illness-related behaviors arises contemporaneously with alterations in 7 to 12 Hz LFP power at approximately 12 min following injection. This process was accompanied by reductions in single-neuron taste response magnitudes and discriminability, and with enhancements in palatability-relatedness-a result reflecting the collapse of responses toward a simple "good-bad" code visible in the entire sample, but focused on a specific subset of GC neurons. Overall, our data show that a state (illness) that profoundly reduces consumption changes basic properties of the sensory cortical response to tastes, in a manner that can easily explain illness' impact on consumption.


Assuntos
Percepção Gustatória , Paladar , Animais , Córtex Cerebral/fisiologia , Neurônios/fisiologia , Ratos , Ratos Long-Evans , Paladar/fisiologia
3.
J Exp Psychol Anim Learn Cogn ; 48(3): 169-178, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35878079

RESUMO

Exposure to two similar stimuli (AX and BX; e.g., two tastes) reduces the extent to which a conditioned response later established to BX generalizes to AX. This example of perceptual learning is more evident when AX and BX are exposed in an alternating manner (AX, BX, AX, BX,…) than when AX and BX occur in separate blocks (e.g., AX, AX,…BX, BX,…). We examined in male rats (N = 126) the impact of rapid alternation to AX and BX on generalization of a taste aversion from BX to AX. Experiment 1 showed that such alternating presentations (with 5-min intervals between AX and BX) reduced generalization relative to blocked exposure; but only as assessed by consumption levels and not by lick cluster size (an index of hedonic reactions). Experiment 1 also showed that the nature of exposure did not affect how A influenced performance to a novel conditioned taste, Y. Experiment 2 replicated the pattern of results involving the different influences of rapidly alternating and blocked exposure on generalization from BX to AX, and showed that this effect was only evident when rats received access to water during the 5-min intervals between AX and BX. These results reinforce parallels between perceptual learning effects in rats and humans, both at empirical and theoretical levels. (PsycInfo Database Record (c) 2022 APA, all rights reserved).


Assuntos
Aprendizagem por Discriminação , Paladar , Animais , Aprendizagem por Associação/fisiologia , Condicionamento Clássico , Generalização Psicológica , Humanos , Aprendizagem , Masculino , Ratos , Paladar/fisiologia
4.
Sensors (Basel) ; 22(13)2022 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-35808472

RESUMO

Taste is a key sense that helps identify different food types and most of this work was carried out on primary tastes rather than generating different flavors. In this work, we proposed a plan to create other flavors rather than primary tastes, adjusted the electrical (40-180 µA) and thermal stimulation (20-38 °C and 38-20 °C), and revealed the digital coding for multi-flavors. Our results showed that different combinations of digital coding could generate different flavors and that tastes related to different stimuli are easy to develop. The novelty of this work is to design other types of flavors and primary tastes. The experimental results demonstrated that the novel method proposed for digital taste coding could realize primary tastes (sweet, sour, salty, spicy, and mint) and mixed flavors. Furthermore, some innovative sensations have been realized, which are sprite, soda water, sweet-sour, salty-sweet, and salty-mint sensations. We presume that this innovation could digitally enhance various flavors.


Assuntos
Paladar , Língua , Paladar/fisiologia
5.
Int J Mol Sci ; 23(15)2022 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-35897802

RESUMO

Sweet taste, a proxy for sugar-derived calories, is an important driver of food intake, and animals have evolved robust molecular and cellular machinery for sweet taste signaling. The overconsumption of sugar-derived calories is a major driver of obesity and other metabolic diseases. A fine-grained appreciation of the dynamic regulation of sweet taste signaling mechanisms will be required for designing novel noncaloric sweeteners with better hedonic and metabolic profiles and improved consumer acceptance. Sweet taste receptor cells express at least two signaling pathways, one mediated by a heterodimeric G-protein coupled receptor encoded by taste 1 receptor members 2 and 3 (TAS1R2 + TAS1R3) genes and another by glucose transporters and the ATP-gated potassium (KATP) channel. Despite these important discoveries, we do not fully understand the mechanisms regulating sweet taste signaling. We will introduce the core components of the above sweet taste signaling pathways and the rationale for having multiple pathways for detecting sweet tastants. We will then highlight the roles of key regulators of the sweet taste signaling pathways, including downstream signal transduction pathway components expressed in sweet taste receptor cells and hormones and other signaling molecules such as leptin and endocannabinoids.


Assuntos
Papilas Gustativas , Paladar , Trifosfato de Adenosina , Animais , Carboidratos , Receptores Acoplados a Proteínas G/genética , Receptores Acoplados a Proteínas G/metabolismo , Transdução de Sinais , Açúcares , Paladar/fisiologia , Papilas Gustativas/metabolismo
6.
Elife ; 112022 07 06.
Artigo em Inglês | MEDLINE | ID: mdl-35791902

RESUMO

Taste detection and hunger state dynamically regulate the decision to initiate feeding. To study how context-appropriate feeding decisions are generated, we combined synaptic resolution circuit reconstruction with targeted genetic access to specific neurons to elucidate a gustatory sensorimotor circuit for feeding initiation in adult Drosophila melanogaster. This circuit connects gustatory sensory neurons to proboscis motor neurons through three intermediate layers. Most neurons in this pathway are necessary and sufficient for proboscis extension, a feeding initiation behavior, and respond selectively to sugar taste detection. Pathway activity is amplified by hunger signals that act at select second-order neurons to promote feeding initiation in food-deprived animals. In contrast, the feeding initiation circuit is inhibited by a bitter taste pathway that impinges on premotor neurons, illuminating a local motif that weighs sugar and bitter taste detection to adjust the behavioral outcomes. Together, these studies reveal central mechanisms for the integration of external taste detection and internal nutritive state to flexibly execute a critical feeding decision.


Assuntos
Proteínas de Drosophila , Paladar , Animais , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/fisiologia , Comportamento Alimentar/fisiologia , Fome , Células Receptoras Sensoriais/fisiologia , Açúcares , Paladar/fisiologia
7.
PLoS Biol ; 20(7): e3001705, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35867663

RESUMO

Gustatory receptors (Grs) are well known for their functions in sensory neurons in detecting food and toxins. An intriguing new study in PLOS Biology provides evidence for a role for Grs in Drosophila epithelia in protecting stressed cells from proteotoxicity.


Assuntos
Proteínas de Drosophila , Drosophila , Animais , Sobrevivência Celular , Drosophila/metabolismo , Proteínas de Drosophila/metabolismo , Células Epiteliais/metabolismo , Proteostase , Receptores de Superfície Celular/metabolismo , Paladar/fisiologia
8.
PLoS Biol ; 20(7): e3001710, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35862315

RESUMO

Gustatory Receptor 64 (Gr64) genes are a cluster of 6 neuronally expressed receptors involved in sweet taste sensation in Drosophila melanogaster. Gr64s modulate calcium signalling and excitatory responses to several different sugars. Here, we discover an unexpected nonneuronal function of Gr64 receptors and show that they promote proteostasis in epithelial cells affected by proteotoxic stress. Using heterozygous mutations in ribosome proteins (Rp), which have recently been shown to induce proteotoxic stress and protein aggregates in cells, we show that Rp/+ cells in Drosophila imaginal discs up-regulate expression of the entire Gr64 cluster and depend on these receptors for survival. We further show that loss of Gr64 in Rp/+ cells exacerbates stress pathway activation and proteotoxic stress by negatively affecting autophagy and proteasome function. This work identifies a noncanonical role in proteostasis maintenance for a family of gustatory receptors known for their function in neuronal sensation.


Assuntos
Proteínas de Drosophila , Drosophila , Animais , Drosophila/metabolismo , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/metabolismo , Células Epiteliais/metabolismo , Proteostase/genética , Receptores de Superfície Celular/genética , Receptores de Superfície Celular/metabolismo , Paladar/fisiologia
9.
Curr Biol ; 32(14): 3070-3081.e5, 2022 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-35772408

RESUMO

Dietary salt detection and consumption are crucial to maintaining fluid and ionic homeostasis. To optimize salt intake, animals employ salt-dependent activation of multiple taste pathways. Generally, sodium activates attractive taste cells, but attraction is overridden at high salt concentrations by cation non-selective activation of aversive taste cells. In flies, high salt avoidance is driven by both "bitter" taste neurons and a class of glutamatergic "high salt" neurons expressing pickpocket23 (ppk23). Although the cellular basis of salt taste has been described, many of the molecular mechanisms remain elusive. Here, we show that ionotropic receptor 7c (IR7c) is expressed in glutamatergic high salt neurons, where it functions with co-receptors IR76b and IR25a to detect high salt and is essential for monovalent salt taste. Misexpression of IR7c in sweet neurons, which endogenously express IR76b and IR25a, confers responsiveness to non-sodium salts, indicating that IR7c is sufficient to convert a sodium-selective gustatory receptor neuron to a cation non-selective one. Furthermore, the resultant transformation of taste neuron tuning switches potassium chloride from an aversive to an attractive tastant. This research provides insight into the molecular basis of monovalent and divalent salt-taste coding.


Assuntos
Proteínas de Drosophila , Drosophila , Animais , Drosophila/metabolismo , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/fisiologia , Cloreto de Sódio/farmacologia , Paladar/fisiologia , Percepção Gustatória/fisiologia
10.
Chem Senses ; 472022 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-35749468

RESUMO

The central gustatory pathway encompasses multiple subcortical and cortical regions whose neural functional connectivity can be modulated by taste stimulation. While gustatory perception has been previously linked to sex, whether and how the gustatory network differently responds to basic tastes between men and women is unclear. Here, we defined the regions of the central gustatory network by a meta-analysis of 35 fMRI taste activation studies and then analyzed the taste-evoked functional connectivity between these regions in 44 subjects (19 women) in a separate 3 Tesla activation study where sweet and bitter solutions, at five concentrations each, were administered during scanning. From the meta-analysis, a network model was set up, including bilateral anterior, middle and inferior insula, thalamus, precentral gyrus, left amygdala, caudate and dorsolateral prefrontal cortex. Higher functional connectivity than in women was observed in men between the right middle insula and bilateral thalami for bitter taste. Men exhibited higher connectivity than women at low bitter concentrations and middle-high sweet concentrations between bilateral thalamus and insula. A graph-based analysis expressed similar results in terms of nodal characteristics of strength and centrality. Our findings add new insights into the mechanisms of taste processing by highlighting sex differences in the functional connectivity of the gustatory network as modulated by the perception of sweet and bitter tastes. These results shed more light on the neural origin of sex-related differences in gustatory perception and may guide future research on the pathophysiology of taste perception in humans.


Assuntos
Caracteres Sexuais , Paladar , Mapeamento Encefálico , Feminino , Humanos , Imageamento por Ressonância Magnética , Masculino , Paladar/fisiologia , Percepção Gustatória/fisiologia , Tálamo
11.
Poult Sci ; 101(7): 101928, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35679679

RESUMO

Elucidating the taste sensing systems in chickens will enhance our understanding of poultry nutrition and improve the feeding strategies used in poultry farming. It is known that chickens lack the sweet taste receptor subunit, taste receptor type 1 member 2 (T1R2), in their genome. Thus, the present study investigated T1R2-independent sweet-sensing pathways in chickens. RT-PCR analysis revealed that glucose transporters known to play an important role in T1R2-independent sweet sensing in mammals-namely sodium-glucose cotransporter 1 (SGLT1) and ATP-gated K+ channel subunits-are expressed in the palate, the main taste organ in chickens. In behavioral tests, chickens slightly preferred glucose, galactose, sucrose, maltose, lactose, and stevioside, while high doses of sucrose and fructose were rejected. Chickens did not show any preference for noncaloric sweeteners or sugar alcohol, such as acesulfame K, aspartame, saccharin, sucralose, or sorbitol. The preference for galactose was inhibited by an inhibitor of SGLT1 in a dose-dependent manner. In addition, we found that glucagon-like peptide 1 (GLP-1) and mRNA of the GLP-1 receptor, which are involved specifically in sweet transmission in mice, are also present in the oral tissues of chickens. The present results imply that chickens can sense various sweet compounds via T1R2-independent pathways in oral tissues.


Assuntos
Galinhas , Paladar , Animais , Galinhas/metabolismo , Galactose , Glucose/metabolismo , Mamíferos/metabolismo , Camundongos , Receptores Acoplados a Proteínas G/genética , Sacarose , Paladar/fisiologia
12.
Chem Senses ; 472022 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-35762652

RESUMO

Dopamine plays a key role in food rewards and sweet-taste stimulation. We examined the basis for behavioral responses to sweet taste in dopamine D3 receptor-deficient (D3-/-) mice by determining whether the absence of D3 receptors affects the sensitivity to dilute sucrose solutions. In experiment 1, we measured the intensity generalization threshold of conditioned taste aversion (CTA) to a 0.2 M sucrose solution. Results showed that the generalization thresholds were 0.025-0.05 M in D3-/- mice and 0.0025-0.005 M in wild-type (WT) mice. In experiment 2, we found that D3-/- and WT mice had similar capabilities to form and extinguish CTAs. Since the intensity generalization threshold is mainly due to a combination of sweet-taste sensitivity and the robust nature of CTA formation, the results showed that taste sensitivity to sucrose in D3-/- mice was lower than that in WT mice. In experiment 3, to test whether the peripheral sensory signaling may also be affected by the disruption of the dopamine D3 receptors, the mRNA expression levels of sweet-taste-related proteins in taste buds of D3-/- mice were determined. The T1R1 and BDNF mRNA expression levels in D3-/- mice were higher than the controls, whereas T1R2, T1R3, α-gustducin, and TRPM5 mRNA were similar. These findings suggest that disruption of dopamine D3 receptor-mediated signaling decreases the sweet-taste sensitivity and alters the mRNA expression levels of some taste-related molecules.


Assuntos
Disgeusia , Receptores de Dopamina D3 , Papilas Gustativas , Paladar , Animais , Disgeusia/genética , Camundongos , RNA Mensageiro/genética , Receptores de Dopamina D3/genética , Sacarose/farmacologia , Paladar/fisiologia , Papilas Gustativas/metabolismo
13.
Elife ; 112022 06 24.
Artigo em Inglês | MEDLINE | ID: mdl-35749158

RESUMO

The tongue is a unique muscular organ situated in the oral cavity where it is involved in taste sensation, mastication, and articulation. As a barrier organ, which is constantly exposed to environmental pathogens, the tongue is expected to host an immune cell network ensuring local immune defence. However, the composition and the transcriptional landscape of the tongue immune system are currently not completely defined. Here, we characterised the tissue-resident immune compartment of the murine tongue during development, health and disease, combining single-cell RNA-sequencing with in situ immunophenotyping. We identified distinct local immune cell populations and described two specific subsets of tongue-resident macrophages occupying discrete anatomical niches. Cx3cr1+ macrophages were located specifically in the highly innervated lamina propria beneath the tongue epidermis and at times in close proximity to fungiform papillae. Folr2+ macrophages were detected in deeper muscular tissue. In silico analysis indicated that the two macrophage subsets originate from a common proliferative precursor during early postnatal development and responded differently to systemic LPS in vivo. Our description of the under-investigated tongue immune system sets a starting point to facilitate research on tongue immune-physiology and pathology including cancer and taste disorders.


Assuntos
Papilas Gustativas , Língua , Animais , Macrófagos , Camundongos , Paladar/fisiologia , Língua/inervação
14.
Proc Natl Acad Sci U S A ; 119(25): e2204238119, 2022 06 21.
Artigo em Inglês | MEDLINE | ID: mdl-35700364

RESUMO

The Anthropocene Epoch poses a critical challenge for organisms: they must cope with new threats at a rapid rate. These threats include toxic chemical compounds released into the environment by human activities. Here, we examine elevated concentrations of heavy metal ions as an example of anthropogenic stressors. We find that the fruit fly Drosophila avoids nine metal ions when present at elevated concentrations that the flies experienced rarely, if ever, until the Anthropocene. We characterize the avoidance of feeding and egg laying on metal ions, and we identify receptors, neurons, and taste organs that contribute to this avoidance. Different subsets of taste receptors, including members of both Ir (Ionotropic receptor) and Gr (Gustatory receptor) families contribute to the avoidance of different metal ions. We find that metal ions activate certain bitter-sensing neurons and inhibit sugar-sensing neurons. Some behavioral responses are mediated largely through neurons of the pharynx. Feeding avoidance remains stable over 10 generations of exposure to copper and zinc ions. Some responses to metal ions are conserved across diverse dipteran species, including the mosquito Aedes albopictus. Our results suggest mechanisms that may be essential to insects as they face challenges from environmental changes in the Anthropocene.


Assuntos
Efeitos Antropogênicos , Drosophila melanogaster , Exposição Ambiental , Reação de Fuga , Metais Pesados , Percepção Gustatória , Paladar , Aedes/fisiologia , Animais , Aprendizagem da Esquiva , Cátions/toxicidade , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/fisiologia , Humanos , Metais Pesados/toxicidade , Receptores Ionotrópicos de Glutamato/metabolismo , Paladar/fisiologia , Percepção Gustatória/fisiologia
15.
J Agric Food Chem ; 70(26): 7851-7870, 2022 Jul 06.
Artigo em Inglês | MEDLINE | ID: mdl-35727887

RESUMO

γ-Glutamyl peptides (γ-GPs) are a group of peptides naturally found in various food sources. The unique γ-bond potentially enables them to resist gastrointestinal digestion and offers high stability in vivo with a longer half-life. In recent years, these peptides have caught researchers' attention due to their ability to impart kokumi taste and elicit various physiological functions via the allosteric activation of the calcium-sensing receptor (CaSR). This review discusses the various food sources of γ-glutamyl peptides, different synthesis modes, allosteric activation of CaSR for taste perception, and associated multiple biological functions they can exhibit, with a special emphasis on their role in modulating chronic inflammation concerning cardiovascular health.


Assuntos
Peptídeos , Receptores de Detecção de Cálcio , Humanos , Inflamação , Peptídeos/química , Paladar/fisiologia , Percepção Gustatória
16.
Neuroscience ; 495: 115-125, 2022 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-35659639

RESUMO

Responses in the rostral (gustatory) nucleus of the solitary tract (rNST) are modified by synaptic interactions within the nucleus and the constitutive membrane properties of the neurons themselves. The potassium current IA is one potential source of modulation. In the caudal NST, projection neurons with IA show lower fidelity to afferent stimulation compared to cells without. We explored the role of an A-type K+ current (IA) in modulating the response to afferent stimulation and GABA-mediated inhibition in the rNST using whole cell patch clamp recording in transgenic mice that expressed channelrhodopsin (ChR2 H134R) in GABAergic neurons. The presence of IA was determined in current clamp and the response to electrical stimulation of afferent fibers in the solitary tract was assessed before and after treatment with the specific Kv4 channel blocker AmmTX3. Blocking IA significantly increased the response to afferent stimulation by 53%. Using dynamic clamp to create a synthetic IA conductance, we demonstrated a significant 14% decrease in responsiveness to afferent stimulation in cells lacking IA. Because IA reduced excitability and is hyperpolarization-sensitive, we examined whether IA contributed to the inhibition resulting from optogenetic release of GABA. Although blocking IA decreased the percent suppression induced by GABA, this effect was attributable to the increased responsiveness resulting from AmmTX3, not to a change in the absolute magnitude of suppression. We conclude that rNST responses to afferent input are regulated independently by IA and GABA.


Assuntos
Neurônios GABAérgicos , Núcleo Solitário , Animais , Estimulação Elétrica , Camundongos , Técnicas de Patch-Clamp , Paladar/fisiologia , Ácido gama-Aminobutírico/farmacologia
17.
J Clin Invest ; 132(13)2022 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-35503420

RESUMO

Constant exposure of the airways to inhaled pathogens requires efficient early immune responses protecting against infections. How bacteria on the epithelial surface are detected and first-line protective mechanisms are initiated are not well understood. We have recently shown that tracheal brush cells (BCs) express functional taste receptors. Here we report that bitter taste signaling in murine BCs induces neurogenic inflammation. We demonstrate that BC signaling stimulates adjacent sensory nerve endings in the trachea to release the neuropeptides CGRP and substance P that mediate plasma extravasation, neutrophil recruitment, and diapedesis. Moreover, we show that bitter tasting quorum-sensing molecules from Pseudomonas aeruginosa activate tracheal BCs. BC signaling depends on the key taste transduction gene Trpm5, triggers secretion of immune mediators, among them the most abundant member of the complement system, and is needed to combat P. aeruginosa infections. Our data provide functional insight into first-line defense mechanisms against bacterial infections of the lung.


Assuntos
Infecções Bacterianas , Paladar , Animais , Células Epiteliais , Imunidade Inata , Camundongos , Pseudomonas aeruginosa , Transdução de Sinais , Paladar/fisiologia , Traqueia
18.
Chem Senses ; 472022 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-35512652

RESUMO

In addition to the well-accepted taste receptors corresponding to the 6 basic taste qualities, sweet, salty, sour, bitter, umami, and fatty, another type of taste receptor, calcium-sensing receptor (CaSR), is located in taste bud cells. CaSR is called the kokumi receptor because its agonists induce koku (or kokumi), a Japanese word meaning the enhancement of flavor characteristics, such as thickness, mouthfulness, and continuity. Kokumi is an important factor in enhancing food palatability. γ-Glu-Val-Gly (EVG) is the most potent agonist of CaSR, which induces a strong kokumi flavor. However, no behavioral studies have been documented in animals using EVG. Here, we show that EVG at low concentrations that do not elicit a taste of its own enhances preferences for umami, fat, and sweet taste solutions in rats. An increased preference for inosine monophosphate (IMP) and Intralipos was the most dominant effect. NPS-2143, an antagonist of CaSR, abolished the additive effect of EVG on IMP and Intralipos solutions. These effects of EVG on taste stimuli are thought to occur in the oral cavity, because the effects of EVG were confirmed in a brief exposure test. The additive effects on IMP and Intralipos remained after the transection of the chorda tympani, indicating that these effects also occur in the palate and/or posterior part of the tongue. Moreover, the additive effects of EVG were verified in electrophysiological taste nerve responses. These results may partially provide the underlying mechanisms for EVG to induce kokumi flavor in humans.


Assuntos
Papilas Gustativas , Paladar , Animais , Suplementos Nutricionais , Dipeptídeos , Ingestão de Alimentos , Inosina Monofosfato/farmacologia , Ratos , Receptores de Detecção de Cálcio , Paladar/fisiologia
19.
Anal Chem ; 94(19): 6976-6985, 2022 05 17.
Artigo em Inglês | MEDLINE | ID: mdl-35503097

RESUMO

The past decade has witnessed tremendous progress achieved in taste research, while few studies focus on interactions among taste compounds. Indeed, sweeteners and acidulants are commonly used food additives, and sweet-sour mixtures always provide improved tastes. For example, sensory studies have shown that sourness suppresses sweetness. However, the degree of sweetness suppression by sourness is difficult to evaluate quantitatively and objectively. Therefore, we propose a biohybrid tongue that is constructed by integrating mammalian gustatory epithelium with a microelectrode array chip. The taste quality and intensity information is coded in time-frequency patterns of local field potential. Different response patterns evoked by sweet and sour stimuli are observed, and the response is dose-dependent. Then, interaction effects of sourness against sweetness are quantified. The results indicate that suppression of sweetness by sourness occurs by increasing sourness concentrations. In summary, this study provides a powerful new tool for quantitative evaluation of sweet, sour, and their binary taste interactions that mimic the mammalian taste system.


Assuntos
Edulcorantes , Paladar , Animais , Mamíferos , Paladar/fisiologia , Língua
20.
Chem Senses ; 472022 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-35522083

RESUMO

Somatostatin neurons in the central nucleus of the amygdala (CeA/Sst) can be parsed into subpopulations that project either to the nucleus of the solitary tract (NST) or parabrachial nucleus (PBN). We have shown recently that inhibition of CeA/Sst-to-NST neurons increased the ingestion of a normally aversive taste stimulus, quinine HCl (QHCl). Because the CeA innervates other forebrain areas such as the lateral hypothalamus (LH) that also sends axonal projections to the NST, the effects on QHCl intake could be, in part, the result of CeA modulation of LH-to-NST neurons. To address these issues, the present study investigated whether CeA/Sst-to-NST neurons are distinct from CeA/Sst-to-LH neurons. For comparison purposes, additional experiments assessed divergent innervation of the LH by CeA/Sst-to-PBN neurons. In Sst-cre mice, two different retrograde transported flox viruses were injected into the NST and the ipsilateral LH or PBN and ipsilateral LH. The results showed that 90% or more of retrograde-labeled CeA/Sst neurons project either to the LH, NST, or PBN. Separate populations of CeA/Sst neurons projecting to these different regions suggest a highly heterogeneous population in terms of synaptic target and likely function.


Assuntos
Tonsila do Cerebelo , Hipotálamo , Tonsila do Cerebelo/metabolismo , Animais , Tronco Encefálico/metabolismo , Hipotálamo/metabolismo , Camundongos , Neurônios/metabolismo , Quinina/farmacologia , Somatostatina/metabolismo , Paladar/fisiologia
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