Single Taste Research Articles

Selective integration of diverse taste inputs within a single taste modality.

A fundamental question in sensory processing is how different channels of sensory input are processed to regulate behavior. Different input channels may converge onto common downstream pathways to drive the same behaviors, or they may activate separate pathways to regulate distinct behaviors. We investigated this question in the Drosophila bitter taste system, which contains diverse bitter-sensing cells residing in different taste organs. First, we optogenetically activated subsets of bitter neurons within each organ. These subsets elicited broad and highly overlapping behavioral effects, suggesting that they converge onto common downstream pathways, but we also observed behavioral differences that argue for biased convergence. Consistent with these results, transsynaptic tracing revealed that bitter neurons in different organs connect to overlapping downstream pathways with biased connectivity. We investigated taste processing in one type of downstream bitter neuron that projects to the higher brain. These neurons integrate input from multiple organs and regulate specific taste-related behaviors. We then traced downstream circuits, providing the first glimpse into taste processing in the higher brain. Together, these results reveal that different bitter inputs are selectively integrated early in the circuit, enabling the pooling of information, while the circuit then diverges into multiple pathways that may have different roles.

Taste Characteristics of Various Amino Acid Derivatives.

Amino acids contribute to the taste of foods. Previous studies on the taste of amino acids focused mainly on α-amino acids, and therefore, the taste characteristics of amino acid derivatives remain unclear. In the present study, we targeted 6 different amino acid derivatives, β-alanine, citrulline, creatine, γ-aminobutyric acid, taurine, and ornithine, and evaluated their taste characteristics in a human sensory study. All tested amino acid derivatives showed multiple taste qualities; no derivatives had only a single taste quality. However, their taste intensities were relatively weak even at high concentrations. Given that the interactions between amino acid derivatives and nucleotide result in taste enhancements, we investigated the effect of inosine 5'-monophosphate (IMP) on the taste characteristics and found that the taste intensity of ornithine increased in the presence of IMP. This finding will be useful for understanding the role of amino acid derivatives as taste substances in daily foods.

Maintenance and turnover of Sox2+ adult stem cells in the gustatory epithelium.

Continuous turnover of taste bud cells in the oral cavity underlies the homeostasis of taste tissues. Previous studies have demonstrated that Sox2+ stem cells give rise to all types of epithelial cells including taste bud cells and non-gustatory epithelial cells in the oral epithelium, and Sox2 is required for generating taste bud cells. Here, we show the dynamism of single stem cells through multicolor lineage tracing analyses in Sox2-CreERT2; Rosa26-Confetti mice. In the non-gustatory epithelium, unicolored areas populated by a cluster of cells expressing the same fluorescent protein grew over time, while epithelial cells were randomly labeled with multiple fluorescent proteins by short-term tracing. Similar phenomena were observed in gustatory epithelia. These results suggest that the Sox2+ stem cell population is maintained by balancing the increase of certain stem cells with the reduction of the others. In the gustatory epithelia, many single taste buds contained cells labeled with different fluorescent proteins, indicating that a single taste bud is composed of cells derived from multiple Sox2+ stem cells. Our results reveal the characteristics of Sox2+ stem cells underlying the turnover of taste bud cells and the homeostasis of taste tissues.

Antifeedant Mechanism of Dodonaea viscosa Saponin A Isolated from the Seeds of Dodonaea viscosa.

Dodonaea viscosa is a medicinal plant which has been used to treat various diseases in humans. However, the anti-insect activity of extracts from D. viscosa has not been evaluated. Here, we found that the total saponins from D. viscosa (TSDV) had strong antifeedant and growth inhibition activities against 4th-instar larvae of Spodoptera litura. The median antifeeding concentration (AFC50) value of TSDV on larvae was 1621.81 μg/mL. TSDV affected the detoxification enzyme system of the larvae and also exerted antifeedant activity possibly through targeting the γ-aminobutyric acid (GABA) system. The AFC50 concentration, the carboxylesterase activity, glutathione S-transferases activity, and cytochrome P450 content increased to 258%, 205%, and 215%, respectively, and likewise the glutamate decarboxylase activity and GABA content to 195% and 230%, respectively, in larvae which fed on TSDV. However, D. viscosa saponin A (DVSA) showed better antifeedant activity and growth inhibition activity in larvae, compared to TSDV. DVSA also exerted their antifeedant activity possibly through targeting the GABA system and subsequently affected the detoxification enzyme system. Further, DVSA directly affected the medial sensillum and the lateral sensillum of the 4th-instar larvae. Stimulation of Spodoptera litura. with DVSA elicited clear, consistent, and robust excitatory responses in a single taste cell.

The capacity and organization of gustatory working memory

Remembering a particular taste is crucial in food intake and associative learning. We investigated whether taste can be dynamically encoded, maintained, and retrieved on short time scales consistent with working memory (WM). We use novel single and multi-item taste recognition tasks to show that a single taste can be reliably recognized despite repeated oro-sensory interference suggesting active and resilient maintenance (Experiment 1, N = 21). When multiple tastes were presented (Experiment 2, N = 20), the resolution with which these were maintained depended on their serial position, and recognition was reliable for up to three tastes suggesting a limited capacity of gustatory WM. Lastly, stimulus similarity impaired recognition with increasing set size, which seemed to mask the awareness of capacity limitations. Together, the results advocate a hybrid model of gustatory WM with a limited number of slots where items are stored with varying precision.

Mastication-Enhanced Taste-Based Classification of Multi-Ingredient Dishes for Robotic Cooking.

Chefs frequently rely on their taste to assess the content and flavor of dishes during cooking. While tasting the food, the mastication process also provides continuous feedback by exposing the taste receptors to food at various stages of chewing. Since different ingredients of the dish undergo specific changes during chewing, the mastication helps to understand the food content. The current methods of electronic tasting, on the contrary, always use a single taste snapshot of a homogenized sample. We propose a robotic setup that uses the mixing to imitate mastication and tastes the dish at two different mastication phases. Each tasting is done using a conductance probe measuring conductance at multiple, spatially distributed points. This data is used to classify 9 varieties of scrambled eggs with tomatoes. We test four different tasting methods and analyze the resulting classification performance, showing a significant improvement over tasting homogenized samples. The experimental results show that tasting at two states of mechanical processing of the food increased classification F1 score to 0.93 in comparison to the traditional tasting of a homogenized sample resulting in F1 score of 0.55. We attribute this performance increase to the fact that different dishes are affected differently by the mixing process, and have different spatial distributions of the salinity. It helps the robot to distinguish between dishes of the same average salinity, but different content of ingredients. This work demonstrates that mastication plays an important role in robotic tasting and implementing it can improve the tasting ability of robotic chefs.

Digital Taste in Mulsemedia Augmented Reality: Perspective on Developments and Challenges

Digitalization of human taste has been on the back burners of multi-sensory media until the beginning of the decade, with audio, video, and haptic input/output(I/O) taking over as the major sensory mechanisms. This article reviews the consolidated literature on augmented reality (AR) in the modulation and stimulation of the sensation of taste in humans using low-amplitude electrical signals. Describing multiple factors that combine to produce a single taste, various techniques to stimulate/modulate taste artificially are described. The article explores techniques from prominent research pools with an inclination towards taste modulation. The goal is to seamlessly integrate gustatory augmentation into the commercial market. It highlights core benefits and limitations and proposes feasible extensions to the already established technological architecture for taste stimulation and modulation, namely, from the Internet of Things, artificial intelligence, and machine learning. Past research on taste has had a more software-oriented approach, with a few trends getting exceptions presented as taste modulation hardware. Using modern technological extensions, the medium of taste has the potential to merge with audio and video data streams as a viable multichannel medium for the transfer of sensory information.

Table for One

Table for One

Taste Bud Connectome: Implications for Taste Information Processing.

Taste buds contain multiple cell types, two of which mediate transduction of specific taste qualities: Type III cells transduce sour while Type II cells transduce either sweet, or bitter or umami. In order to discern the degree of interaction between different cell types and specificity of connectivity with the afferent nerve fibers (NFs), we employed serial blockface scanning electron microscopy (sbfSEM) through five circumvallate mouse taste buds. Points of contact between Type II and Type III cells are rare and lack morphologically identifiable synapses, suggesting that interaction between these cell types does not occur via synapses. Of the 127 NFs that make synaptic contacts with taste cells in the sampling volume, ∼70% (n = 91) synapse with only one taste cell while 32 fibers synapse exclusively with multiple Type II cells or multiple Type III cells. Our data do not rule out multimodal fibers innervating Type II cells of separate taste qualities. Notably, four fibers (∼3%) synapse with both Type II and Type III cells, forming both mitochondrial and vesicular synapses on the different cell types. Since Type II and Type III cells transduce different taste qualities, these dual connected fibers are not consistent with a absolute labeled-line encoding system. Further, our data reveal considerable variation in both the number of synapses per cell/nerve pair and the number of innervating NFs per taste cell, both of which likely have consequences for encoding taste quality and concentration. Finally, we identify a subset of Type II cells which may represent an immature stage.SIGNIFICANCE STATEMENT Taste buds, the sensory end organs for the sense of taste, contain multiple types of sensory cells, with each responding to one of the primary tastes: salt, sweet, sour, bitter, and umami. In order to determine the degree of interaction between cell types and specificity of connectivity to afferent nerves, we employed serial blockface electron microscopy (EM) of mouse circumvallate taste buds. We find no synapses between cell types within the taste bud suggesting that any interactions are indirect. While the majority of nerve fibers (NFs) connect to a single type of taste cell, 3.1% of the fibers branch to receive input from taste cells of different specificities. Thus, taste cannot entirely be carried along NFs dedicated to single taste qualities.

Less light, better bite: How ambient lighting influences taste perceptions

Atmospheric factors within a retail environment provide efficient and effective methods for influencing customer behavior. Drawing on the concept of sensory compensation, this research investigates how ambient lighting influences taste perceptions. Three studies demonstrate that dim lighting enhances taste perceptions. The results of Studies 1a and 1b provide support that low lighting positively influences consumers' perceived taste of single taste dimension foods (e.g., sweet). Study 2 shows the number of taste dimensions (e.g., sweet vs. sweet and salty) stimulated serves as a boundary condition, attenuating the significant effect of dim lighting on taste perceptions.

Bitter Taste Disrupts Spatial Discrimination of Piperine-Evoked Burning Sensations: A Pilot Study.

Simple SummaryThe chemical senses smell, taste, and trigeminal sense enable us to interact with the environment and play an essential role in protecting us from hazardous events. It is theorized that capsaicin and piperine not only elicit burning, but also bitter sensations through bitter taste-responding gustatory receptor cells that possess special channels. Similar psychophysiological responses to capsaicin and piperine suggest that bitter taste might also disrupt the spatial discrimination to piperine-induced burning sensations. Results showed that bitter taste disrupted the spatial discrimination of piperine-evoked burning sensations, providing further evidence for a qualitative similarity between burning and bitter sensations and the usefulness of chemical irritants in spatial discrimination tasks.This study aimed to investigate the perceptual similarity between piperine-induced burning sensations and bitter taste using piperine-impregnated taste strips (PTS). This pilot study included 42 healthy participants. PTS of six ascending concentrations (1 mg, 5 mg, 10 mg, 15 mg, 20 mg, and 25 mg piperine/dL 96% ethanol) were presented at the anterior tongue, and participants rated perceived intensity and duration. Then, participants performed a spatial discrimination task in which they had to report which of the two strips presented to the anterior tongue contained an irritating stimulus when one strip was always a PTS while the other strip was impregnated with either a single taste quality (sweet or bitter) or a blank strip. Repeated measures one-way ANOVA revealed that burning sensations of higher concentrated PTS were perceived more intense and more prolonged compared to lower concentrated PTS. McNemar’s test showed that PTS were identified correctly significantly less often when presented with bitter strips compared to when presented with blank (p = 0.002) or sweet strips (p = 0.017). Our results showed that bitter taste disrupts the spatial discrimination of piperine-evoked burning sensations. PTS might serve as a basis for further studies on disease-specific patterns in chemosensory disorders.

Flannery: The Storied Life of the Writer from Georgia dir. by Mark Bosco, SJ and Elizabeth Coffman

Reviewed by: Flannery: The Storied Life of the Writer from Georgia dir. by Mark Bosco, SJ and Elizabeth Coffman Daniel Moran Flannery: The Storied Life of the Writer from Georgia. Directed by Mark Bosco, SJ and Elizabeth Coffman. USA: Long Distance Productions in association with American Masters, 2020. 97 minutes. Early in Flannery, Richard Rodriguez offers a perfect description of O'Connor's art: "What's happening here is something so remarkable that the profane meets with the sacred, and it's within that comic meeting that the stories operate. This is the way Flannery O'Connor works. You either get it or you don't, and if you don't, then don't go to the carnival." While this remark concerns "A Temple of the Holy Ghost," it applies to O'Connor's entire output. Flannery, directed by Mark Bosco, SJ and Elizabeth Coffman, is an invitation to the O'Connor carnival for readers new to her work and those who have been reading her for years. It's instructive for viewers who get it and viewers who don't, offering the former glimpses of O'Connor's life and work that remind them of what drove them to O'Connor in the first place and the latter an argument about why O'Connor is one of the greatest writers of the twentieth century. Like other carnivals, it's filled with thrills, noise, fun, and occasional freaks. Coffman and Bosco know their way around O'Connor's Georgia and the film is filled with images and sounds of her childhood home in Savannah and her later home at Andalusia, the Milledgeville farm where she lived with her mother. The perfect soundtrack includes Lucinda Williams's "Get Right with God," The Singing Nun's [End Page 47] "Dominique," Bruce Springsteen's "Nebraska," and, of course, Bessie Smith's "A Good Man Is Hard to Find," all of which complement the aspect of O'Connor's life or work under examination. Major players in O'Connor studies (Ralph Wood, Bruce Gentry, William Sessions) offer insights into the fiction; familiar figures from O'Connor's life (Sally Fitzgerald, Mary Gordon, Louise and Frances Florencourt) speak of O'Connor as a friend and relation; celebrities from the screen (Conan O'Brien and Tommy Lee Jones) describe their first encounters with her work; familiar authors (Tobias Wolf, Mary Karr, Alice McDermott) read favorite passages and then look at the camera with expressions that say the same thing O'Connor's readers have been asking for almost seventy years: Can you believe that anyone came up with this? Flannery dutifully walks the reader through the major events of O'Connor's life, guided by biographer Brad Gooch. After the obligatory newsreel of the six-year-old O'Connor and her backwards-walking chicken, the film highlights her residencies at Georgia State College for Women, the Iowa Writers' Workshop, Yaddo (the artists' colony in Saratoga Springs), New York City, and the Fitzgeralds' Connecticut farm—all offered as places from which O'Connor broadened her vision of human nature and became determined to articulate that vision in her art. The directors include a segment on Erik Langkjaer as O'Connor's single (and fruitless) taste of romantic love (and partial inspiration for the devilish Manly Pointer), but this and other events are more changes of address or common experiences than dramatic milestones. In a 1958 letter to Betty Hester, O'Connor said, "There won't be any biographies of me, for only one reason: lives spent between the house and the chicken farm do not make for exciting copy." She was wrong on the first count but right on the second: the real interest in O'Connor's life is not where she lived but how she thought, wrote, and prayed. Her love of God is far more interesting than her crush on a traveling salesman. Coffman and Bosco take great pains to ensure that O'Connor's voice is heard throughout the film. Letters, stories, and essays are quoted frequently, often with accompanying graphics and Mary Steenburgen playing the role of Flannery. The most striking of these quotations is offered by Mary Karr, who reads from...

Quantitative Analysis of Taste Bud Cell Numbers in the Circumvallate and Foliate Taste Buds of Mice.

A mouse single taste bud contains 10-100 taste bud cells (TBCs) in which the elongated TBCs are classified into 3 cell types (types I-III) equipped with different taste receptors. Accordingly, differences in the cell numbers and ratios of respective cell types per taste bud may affect taste-nerve responsiveness. Here, we examined the numbers of each immunoreactive cell for the type II (sweet, bitter, or umami receptor cells) and type III (sour and/or salt receptor cells) markers per taste bud in the circumvallate and foliate papillae and compared these numerical features of TBCs per taste bud to those in fungiform papilla and soft palate, which we previously reported. In circumvallate and foliate taste buds, the numbers of TBCs and immunoreactive cells per taste bud increased as a linear function of the maximal cross-sectional taste bud area. Type II cells made up approximately 25% of TBCs irrespective of the regions from which the TBCs arose. In contrast, type III cells in circumvallate and foliate taste buds made up approximately 11% of TBCs, which represented almost 2 times higher than what was observed in the fungiform and soft palate taste buds. The densities (number of immunoreactive cells per taste bud divided by the maximal cross-sectional area of the taste bud) of types II and III cells per taste bud are significantly higher in the circumvallate papillae than in the other regions. The effects of these region-dependent differences on the taste response of the taste bud are discussed.

An Experimental Bacteriostasis of the Banxiaxiexin Decoction and 7 Kinds of Single Taste Traditional Chinese Medicine on Helicobacter Pylori Resistant Strains in Vitro

Objectives: To research experimental bacteriostasis on the Banxiaxiexin decoction and 7 kinds of single taste Traditional Chinese Medicine (TCM) for Helicobacter pylori resistant strains in vitro. Methods: Collecting specimens of gastric mucosa in patients with upper gastrointestinal disease, separated and identified 8 strains of Hp resistant strains, the E-test methods of metronidazole and clarithromycin, drug resistance status of amoxicillin, selected eight strains of clinical drug resistance strains; Using liquid dilution method to determine the Banxiaxiexin decoction and 7 kinds of single Chinese medicine clinical drug-resistant strains of 8 strains of antibacterial effect in vitro. Results: Banxiaxiexin decoction MIC is 0.31 mg/ml, MIC of Radix scutellariae is 0.09 mg/ml, Rhizoma coptidis MIC 0. 16 mg/ml, Glycyrrhizin realness MIC 0. 31 mg/ml, Ginseng MIC 0. 75 mg/ml, there are four of seven kinds of single taste Traditional Chinese Medicine of TCM has bacteriostatic action, the order of antibacterial strength: Scutellaria baicalensis>Coptis chinesis>Glycyrrhizin realness >Ginseng, three kinds of Pinellia, Jujube and dry Zingibe in vitro for H. P ylori no inhibition, the method of MIC with liquid dilution in this decoction were determined, the decoction of resistant isolates average MIC isolates was 0.20±0.09mg/ml, the results showed that this decoction have stronger antibacterial effect on eight kinds of drug resistant strains in vitro. Banxiaxiexin decoction and 4kinds of single taste TCM have stronger antibacterial effect on drug resistant strains in vitro. Conclusion: Banxiaxiexin decoction and 4 kinds of single TCM have strong bacteriostatic effect on the bacteria resistance of Helicobacter pylori strains in vitro, therefore, we suggest that this decoction could be used as an effective method in the treatment of resistant HP associated gastritis.

An Experimental Bacteriostasis of the Banxiaxiexin Decoction and 7 Kinds of Single Taste Traditional Chinese Medicine on Helicobacter Pylori Resistant Strains in Vitro

Objectives: To research experimental bacteriostasis on the Banxiaxiexin decoction and 7 kinds of single taste Traditional Chinese Medicine (TCM) for Helicobacter pylori resistant strains in vitro. Methods: Collecting specimens of gastric mucosa in patients with upper gastrointestinal disease, separated and identified 8 strains of Hp resistant strains, the E-test methods of metronidazole and clarithromycin, drug resistance status of amoxicillin, selected eight strains of clinical drug resistance strains; Using liquid dilution method to determine the Banxiaxiexin decoction and 7 kinds of single Chinese medicine clinical drug-resistant strains of 8 strains of antibacterial effect in vitro. Results: Banxiaxiexin decoction MIC is 0.31 mg/ml, MIC of Radix scutellariae is 0.09 mg/ml, Rhizoma coptidis MIC 0. 16 mg/ml, Glycyrrhizin realness MIC 0. 31 mg/ml, Ginseng MIC 0. 75 mg/ml, there are four of seven kinds of single taste Traditional Chinese Medicine of TCM has bacteriostatic action, the order of antibacterial strength: Scutellaria baicalensis>Coptis chinesis>Glycyrrhizin realness >Ginseng, three kinds of Pinellia, Jujube and dry Zingibe in vitro for H. P ylori no inhibition, the method of MIC with liquid dilution in this decoction were determined, the decoction of resistant isolates average MIC isolates was 0.20±0.09mg/ml, the results showed that this decoction have stronger antibacterial effect on eight kinds of drug resistant strains in vitro. Banxiaxiexin decoction and 4kinds of single taste TCM have stronger antibacterial effect on drug resistant strains in vitro. Conclusion: Banxiaxiexin decoction and 4 kinds of single TCM have strong bacteriostatic effect on the bacteria resistance of Helicobacter pylori strains in vitro, therefore, we suggest that this decoction could be used as an effective method in the treatment of resistant HP associated gastritis.

A conserved odorant binding protein is required for essential amino acid detection in Drosophila

Animals need to detect in the food essential amino acids that they cannot synthesize. We found that the odorant binding protein OBP19b, which is highly expressed in Drosophila melanogaster taste sensilla, is necessary for the detection of several amino acids including the essential l-phenylalanine. The recombinant OBP19b protein was produced and characterized for its binding properties: it stereoselectively binds to several amino acids. Using a feeding-choice assay, we found that OBP19b is necessary for detecting l-phenylalanine and l-glutamine, but not l-alanine or D-phenylalanine. We mapped the cells expressing OBP19b and compared the electrophysiological responses of a single taste sensillum to several amino acids: OBP19b mutant flies showed a reduced response compared to control flies when tested to preferred amino acids, but not to the other ones. OBP19b is well conserved in phylogenetically distant species suggesting that this protein is necessary for detection of specific amino acids in insects.

The Cost of Heterogeneity: Can Density Peaks Clustering Improve CES Aggregation?

This paper applies recent advances in machine learning to a long-standing macroeconomics question by using density peaks clustering to improve estimation of aggregate price indexes. To measure a price index that properly accounts for consumer welfare, it is important to consider the effect of changes in product variety. Standard methods for estimating this effect using CES demand systems implicitly rely on the assumption that consumer tastes can be accurately represented by a single taste parameter. However, if consumers have heterogeneous unobserved tastes across goods, the estimated aggregate elasticity will tend to be lower than that of the groups. By clustering consumers into groups that share similar tastes, we can accurately estimate elasticity and get more representative measurements for each consumer’s cost of living. Applying the method to a panel of consumer retail purchases, I show that methods that ignore consumer heterogeneity imply elasticities on average 20% below my method and inflation rates about half a percentage point per year lower than a weighted average of the heterogeneous groups.

Electroencephalographic (EEG) alterations in young women with high subclinical eating pathology levels: a quantitative EEG study.

To explore electroencephalographic (EEG) alterations in young women with different eating disorder (ED) psychopathology levels. Thirty-seven young women completed general and ED psychopathology (i.e., the ED Examination Questionnaire; EDE-Q) measures. EEG power spectra data were investigated in two conditions: (a) 5 min of resting state (RS) and (b) 5 min of RS after a single taste of a milkshake (ML-RS). EEG analyses were performed using exact Low-Resolution Electromagnetic Tomography software (eLORETA). Cluster analysis performed on the EDE-Q responses revealed a group of 17 women with high levels of ED pathology falling into the subclinical (i.e., sub-threshold) EDs category and a group of 20 women with low levels of ED pathology (controls). In the RS conditions, no significant modifications were observed between groups. Compared to controls, women with subclinical EDs showed an increase in theta activity in the parieto-occipital areas in the ML-RS condition. After controlling for body mass index and general psychopathology, theta activity in these brain structures was positively associated with EDE-Q global and subscale (restraint, shape and weight concern) scores. Our results may reflect the neurophysiological substrate of ED psychopathology core features like shape/weight concerns. Previous brain imaging and qEEG studies with full-syndrome ED patients also underscored the involvement of parieto-occipital areas in ED pathophysiology. These studies also found brain alterations in the RS condition, not observed here. This is notable given that full-syndrome and subclinical EDs are considered as different manifestations of the same disease along a severity spectrum. Level V, cross-sectional, electroencephalographic, descriptive study.

The shapes associated with the concept of ‘sweet and sour’ foods

Research on taste-shape correspondences has focused on one-to-one taste/shape matching tasks. However, foods and drinks tend to involve multiple shapes (or shape attributes) and tastes that co-occur at different moments of our eating experiences. In the present research, we assessed whether food concepts involving more than one taste (e.g., “sweet and sour”) would be associated with pairs of round and/or angular shapes. The participants matched pairs comprising angular and round shapes with “sweet and sour” food concepts more often than with other single taste and taste combination concepts, in a manner that is broadly consistent with studies involving one-to-one taste/shape matches. These results were observed both when the participants were presented with the shape pairs alone (Experiment 1) or along with a product’s packaging (Experiment 2). We conclude by presenting possible explanations for the results obtained, as well as directions for future research.

Dual functional extracellular recording using a light-addressable potentiometric sensor for bitter signal transduction

This paper presents a dual functional extracellular recording biosensor based on a light-addressable potentiometric sensor (LAPS). The design and fabrication of this biosensor make it possible to record both extracellular membrane potential changes and ATP release from a single taste bud cell for the first time. For detecting ATP release, LAPS chip was functionalized with ATP-sensitive DNA aptamer by covalent immobilization. Taste bud cells isolated from rat were cultured on LAPS surface. When the desired single taste bud cell was illuminated by modulated light, ATP release from single taste bud cells can be measured by recording the shifts of bias voltage-photocurrent curves (I-V curves) when the LAPS chip is working in discrete mode. On the other hand, extracellular membrane potential changes can be monitored by recording the fluctuation of LAPS photocurrent when the LAPS chip is working in continuous mode. The results show this biosensor can effectively record the enhancive effect of the bitter substance and inhibitory effect of the carbenoxolone (CBX) on the extracellular membrane potential changes and ATP release of single taste bud cells. In addition, the inhibitory effect of CBX also confirms LAPS extracellular recordings are originated from bitter signal transduction. It is proved this biosensor is suitable for extracellular recording of ATP release and membrane potential changes of single taste bud cells. It is suggested this biosensor could be applied to investigating taste signal transduction at the single-cell level as well as applied to other types of cells which have similar functions to taste bud cells.