MDR1 in taste buds of rat vallate papilla: functional, immunohistochemical, and biochemical evidence

1998 ◽  
Vol 274 (1) ◽  
pp. C182-C191 ◽  
Author(s):  
Ingrid Jakob ◽  
Ingeborg A. Hauser ◽  
Frank Thévenod ◽  
Bernd Lindemann
Keyword(s):  
Fluorescent Dyes ◽  
Taste Buds ◽  
Sensory Cells ◽  
Acetoxymethyl Ester ◽  
Slow Increase ◽  
Lingual Epithelium ◽  
Western Blots ◽  
Tissue Sections ◽  
Taste Cells ◽  
Posterior Tongue

Multidrug resistance P-glycoprotein (MDR1) is a membrane protein of 150–170 kDa that catalyzes the ATP-driven efflux of hydrophobic xenobiotics, including fluorescent dyes, from cells. Expressed in many epithelial tissues and in the endothelia of the blood-brain barrier, the MDR1 protein provides major routes of detoxification. We found that taste cells of the rat vallate papilla (VP; posterior tongue) had only a slow increase in fluorescence due to uptake of the hydrophobic dye calcein acetoxymethyl ester. However, the development of fluorescence was accelerated two- to threefold by substrates and/or inhibitors of MDR1, such as verapamil, tamoxifen, and cyclosporin A, and by addition of the transport-blocking antibody to MDR1, UIC2. Western blots of vallate tissue rich in taste buds with the MDR1-specific monoclonal antibodies C219 and C494 revealed an immunoreactive protein at ∼170 kDa. In contrast, the lingual epithelium surrounding the VP showed a much weaker band with these antibodies. Furthermore, using the antibodies C494 and UIC2 with tissue sections, MDR1-like immunoreactivity was found in taste cells. These results show that MDR1 is present and functional in vallate taste cells of the rat. MDR1-related transport may achieve active elimination of xenobiotics from the sensory cells and thereby protect the peripheral taste organs from potentially harmful molecules contained in an animal’s food.

scholarly journals Identification of electrophysiologically distinct cell subpopulations in Necturus taste buds.

1993 ◽  
Vol 102 (1) ◽  
pp. 143-170 ◽  
Author(s):  
A Bigiani ◽  
S D Roper
Keyword(s):  
Lucifer Yellow ◽  
Taste Buds ◽  
Taste Bud ◽  
Basal Cells ◽  
Patch Clamp Technique ◽  
Lingual Epithelium ◽  
Voltage Gated ◽  
Receptor Cells ◽  
Taste Cells ◽  
K Currents

We used the patch clamp technique to record from taste cells in thin transverse slices of lingual epithelium from Necturus maculosus. In this preparation, the epithelial polarity and the cellular organization of the taste buds, as well as the interrelationships among cells within the taste bud, were preserved. Whole-cell recording, combined with cell identification using Lucifer yellow, allowed us to identify distinct subpopulations of taste cells based on their electrophysiological properties. Receptor cells could be divided in two groups: one group was characterized by the presence of voltage-gated Na+, K+, and Ca2+ currents; the other group was characterized by the presence of K+ currents only. Therefore, receptor cells in the first group would be expected to be capable of generating action potentials, whereas receptor cells in the second group would not. Basal taste cells could also be divided into two different groups. Some basal cells possessed voltage-gated Na+, K+, and Ca2+ conductances, whereas other basal cells only had K+ conductance. In addition to single taste cells, we were able to identify electrically coupled taste cells. We monitored cell-cell coupling by measuring membrane capacitance and by observing Lucifer yellow dye coupling. Electrical coupling in pairs of dye-coupled taste receptor cells was strong, as indicated by experiments with the uncoupling agent 1-octanol. Electrically coupled receptor cells possessed voltage-gated currents, including Na+ and K+ currents. The electrophysiological differentiation among taste cells presumably is related to functional diversifications, such as different chemosensitivities.

scholarly journals A permeability barrier surrounds taste buds in lingual epithelia

2015 ◽  
Vol 308 (1) ◽  
pp. C21-C32 ◽  
Author(s):  
Robin Dando ◽  
Elizabeth Pereira ◽  
Mani Kurian ◽  
Rene Barro-Soria ◽  
Nirupa Chaudhari ◽  
...  
Keyword(s):  
Tight Junctions ◽  
Basic Research ◽  
Taste Buds ◽  
Cell Junctions ◽  
Sensory Cells ◽  
Permeability Barrier ◽  
Entire Body ◽  
Lingual Epithelium ◽  
Tissue Samples ◽  
Extracellular Matrix Components

Epithelial tissues are characterized by specialized cell-cell junctions, typically localized to the apical regions of cells. These junctions are formed by interacting membrane proteins and by cytoskeletal and extracellular matrix components. Within the lingual epithelium, tight junctions join the apical tips of the gustatory sensory cells in taste buds. These junctions constitute a selective barrier that limits penetration of chemosensory stimuli into taste buds (Michlig et al. J Comp Neurol 502: 1003–1011, 2007). We tested the ability of chemical compounds to permeate into sensory end organs in the lingual epithelium. Our findings reveal a robust barrier that surrounds the entire body of taste buds, not limited to the apical tight junctions. This barrier prevents penetration of many, but not all, compounds, whether they are applied topically, injected into the parenchyma of the tongue, or circulating in the blood supply, into taste buds. Enzymatic treatments indicate that this barrier likely includes glycosaminoglycans, as it was disrupted by chondroitinase but, less effectively, by proteases. The barrier surrounding taste buds could also be disrupted by brief treatment of lingual tissue samples with DMSO. Brief exposure of lingual slices to DMSO did not affect the ability of taste buds within the slice to respond to chemical stimulation. The existence of a highly impermeable barrier surrounding taste buds and methods to break through this barrier may be relevant to basic research and to clinical treatments of taste.

scholarly journals Insulin Is Transcribed and Translated in Mammalian Taste Bud Cells

Endocrinology ◽  
2018 ◽  
Vol 159 (9) ◽  
pp. 3331-3339 ◽  
Author(s):  
Máire E Doyle ◽  
Jennifer L Fiori ◽  
Isabel Gonzalez Mariscal ◽  
Qing-Rong Liu ◽  
Erin Goodstein ◽  
...  
Keyword(s):  
Green Fluorescence Protein ◽  
Taste Buds ◽  
Taste Bud ◽  
Lingual Epithelium ◽  
Processing Enzymes ◽  
Taste Cells ◽  
Specific Proteins ◽  
Fluorescence Protein ◽  
Taste Bud Cells

Abstract We and others have reported that taste cells in taste buds express many peptides in common with cells in the gut and islets of Langerhans in the pancreas. Islets and taste bud cells express the hormones glucagon and ghrelin, the same ATP-sensitive potassium channel responsible for depolarizing the insulin-secreting β cell during glucose-induced insulin secretion, as well as the propeptide-processing enzymes PC1/3 and PC2. Given the common expression of functionally specific proteins in taste buds and islets, it is surprising that no one has investigated whether insulin is synthesized in taste bud cells. Using immunofluorescence, we demonstrated the presence of insulin in mouse, rat, and human taste bud cells. By detecting the postprocessing insulin molecule C-peptide and green fluorescence protein (GFP) in taste cells of both insulin 1-GFP and insulin 2-GFP mice and the presence of the mouse insulin transcript by in situ hybridization, we further proved that insulin is synthesized in individual taste buds and not taken up from the parenchyma. In addition to our cytology data, we measured the level of insulin transcript by quantitative RT-PCR in the anterior and posterior lingual epithelia. These analyses showed that insulin is translated in the circumvallate and foliate papillae in the posterior, but only insulin transcript was detected in the anterior fungiform papillae of the rodent tongue. Thus, some taste cells are insulin-synthesizing cells generated from a continually replenished source of precursor cells in the adult mammalian lingual epithelium.

Phospholipase A2 is involved in mediating the effect of extracellular Ca2+ on apical K+ channels in rat TAL

1997 ◽  
Vol 273 (3) ◽  
pp. F421-F429 ◽  
Author(s):  
W. Wang ◽  
M. Lu ◽  
M. Balazy ◽  
S. C. Hebert
Keyword(s):  
Phospholipase A2 ◽  
Fluorescent Dyes ◽  
Rat Kidney ◽  
K Channel ◽  
Thick Ascending Limb ◽  
Channel Activity ◽  
Patch Clamp Technique ◽  
Acetoxymethyl Ester ◽  
K Channels ◽  
Stimulation Of

Raising extracellular Ca2+ (Ca2+o) stimulating the Ca(2+)-sensing receptor (CaR) decreased the activity of the apical 70-pS K+ channel via a cytochrome P-450-dependent mechanism in the thick ascending limb (TAL) of the rat kidney [W. H. Wang, M. Lu, and S. C. Hebert. Am. J. Physiol. 270 (Cell Physiol. 39): C103-C111, 1996]. We have now used the patch-clamp technique and fluorescent dyes to investigate the signaling mechanism by which this effect is produced. Addition of 500 microM gadolinium (Gd3+), an agent which has been shown to activate the CaR (E. M. Brown, G. Gamba, D. Riccardi, M. Lombardi, R. Butters, O. Kifor, A. Sun, M. A. Hediger, J. Lytton, and S. C. Hebert. Nature 366: 575-580, 1993), mimics the inhibitory effect of raising Ca2+o from 1.1 to 5 mM on channel activity. Effects of the high Ca2+o and Gd3+ were abolished by blockade of phospholipase A2 (PLA2) but not by inhibition of phospholipase C (PLC). Raising Ca2+o also increased 20-hydroxyeicosatetraenoic acid production significantly. To investigate the effect of stimulation of the CaR on intracellular Ca2+ (Ca2+i), we used the acetoxymethyl ester of fura 2 to monitor the Ca2+i. Raising Ca2+o from 1.1 to 5 mM increased the Ca2+i significantly from 50 to 150 nM. However, addition of thapsigargin failed to abolish the effect of 5 mM Ca2+o on Ca2+i. Also, application of Gd3+ only slightly increased the Ca2+i, suggesting that elevation of the Ca2+i by high Ca2+o was the result of an influx of Ca2+ rather than enhanced Ca2+ release from Ca2+ stores. That the increase in Ca2+ influx is not mainly responsible for the effect of stimulating the CaR on channel activity is further supported by experiments in which 500 microM Gd3+ inhibited the K+ channel in cell-attached patches in a Ca(2+)-free bath. Furthermore, addition of 500 microM Gd3+ or 5 mM Ca2+o decreased intracellular Na+ measured with fluorescent sodium indicator, suggesting inhibition of Na+ transport. We conclude that PLA2 is involved in the stimulation of the CaR-induced inhibition of apical K+ channels in the TAL.

scholarly journals Morphological and ultrastructural characteristics of the tongue of wild boar

2020 ◽  
Vol 64 (2) ◽  
Author(s):  
Gabriela de Souza Reginato ◽  
Gabriela Klein Barbosa ◽  
Amanda Olivotti Ferreira ◽  
Bruno Gomes Vasconcelos ◽  
Rose Eli Grassi Rici ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Wild Boar ◽  
Structural Characteristics ◽  
Morphological Characteristics ◽  
Taste Buds ◽  
Flower Bud ◽  
Fungiform Papilla ◽  
Lingual Epithelium ◽  
Lingual Papillae ◽  
Conical Shape

The present study aimed to describe the structural and ultrastructural morphological characteristics of the lingual epithelium and the connective tissue cores (CTCs) of wild boar (Sus scrofa). The tongues were processed for light microscopy, scanning electron microscopy, and transmission electron microscopy. In this study, we revealed the filiform, fungiform, foliate, and vallate papillae. The filiform papilla is elongated with a conical shape and its CTC has a conical shape; the fungiform papilla is rounded with a dome-shape and its CTC is flower bud; the foliate papilla is formed by four pairs of epithelial folds and irregular grooves, and its CTC is thin with adjacent conjunctive projections, and taste buds and serous glands in the epithelial layer have been evidenced; and the vallate papilla is oval surrounded by a groove with increases of epithelium surface, and the CTC is formed by numerous connective projections lined. Also noted were serous gland and taste buds on the medial wall of the vallate papilla. The epithelium has the keratinized, granular, spinous, basal, and lamina propria layers. In conclusion, we found new descriptions and shapes of the CTCs of the lingual papillae. In addition, we demonstrated the epithelium structural characteristics, the nuclear distribution between the epithelial layers, and the ultrastructural aspects of the dorsal epithelium of the tongue.

scholarly journals Expression and Secretion of TNF-α in Mouse Taste Buds: A Novel Function of a Specific Subset of Type II Taste Cells

PLoS ONE ◽  
2012 ◽  
Vol 7 (8) ◽  
pp. e43140 ◽  
Author(s):  
Pu Feng ◽  
Hang Zhao ◽  
Jinghua Chai ◽  
Liquan Huang ◽  
Hong Wang
Keyword(s):  
Taste Buds ◽  
Type Ii ◽  
Specific Subset ◽  
Tnf Α ◽  
Taste Cells ◽  
Mouse Taste

scholarly journals Loading acetoxymethyl ester fluorescent dyes into the cytoplasm of Arabidopsis and Commelina guard cells

2002 ◽  
Vol 153 (3) ◽  
pp. 527-533 ◽  
Author(s):  
Kazuyuki Kuchitsu ◽  
John M. Ward ◽  
Gethyn J. Allen ◽  
Ilona Schelle ◽  
Julian I. Schroeder
Keyword(s):  
Fluorescent Dyes ◽  
Guard Cells ◽  
Acetoxymethyl Ester

scholarly journals Acetic acid modulates spike rate and spike latency to salt in peripheral gustatory neurons of rats

2012 ◽  
Vol 108 (9) ◽  
pp. 2405-2418 ◽  
Author(s):  
Joseph M. Breza ◽  
Robert J. Contreras
Keyword(s):  
Acetic Acid ◽  
Artificial Saliva ◽  
Type I ◽  
Dependent Manner ◽  
Chorda Tympani ◽  
Gustatory System ◽  
Chorda Tympani Nerve ◽  
Concentration Dependent Manner ◽  
Lingual Epithelium ◽  
Taste Cells

Sour and salt taste interactions are not well understood in the peripheral gustatory system. Therefore, we investigated the interaction of acetic acid and NaCl on taste processing by rat chorda tympani neurons. We recorded multi-unit responses from the severed chorda tympani nerve (CT) and single-cell responses from intact narrowly tuned and broadly tuned salt-sensitive neurons in the geniculate ganglion simultaneously with stimulus-evoked summated potentials to signal when the stimulus contacted the lingual epithelium. Artificial saliva served as the rinse and solvent for all stimuli [0.3 M NH4Cl, 0.5 M sucrose, 0.1 M NaCl, 0.01 M citric acid, 0.02 M quinine hydrochloride (QHCl), 0.1 M KCl, 0.003–0.1 M acetic acid, and 0.003–0.1 M acetic acid mixed with 0.1 M NaCl]. We used benzamil to assess NaCl responses mediated by the epithelial sodium channel (ENaC). The CT nerve responses to acetic acid/NaCl mixtures were less than those predicted by summing the component responses. Single-unit analyses revealed that acetic acid activated acid-generalist neurons exclusively in a concentration-dependent manner: increasing acid concentration increased response frequency and decreased response latency in a parallel fashion. Acetic acid suppressed NaCl responses in ENaC-dependent NaCl-specialist neurons, whereas acetic acid-NaCl mixtures were additive in acid-generalist neurons. These data suggest that acetic acid attenuates sodium responses in ENaC-expressing-taste cells in contact with NaCl-specialist neurons, whereas acetic acid-NaCl mixtures activate distinct receptor/cellular mechanisms on taste cells in contact with acid-generalist neurons. We speculate that NaCl-specialist neurons are in contact with type I cells, whereas acid-generalist neurons are in contact with type III cells in fungiform taste buds.

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