“Tripartite Synapses” in Taste Buds: A Role for Type I Glial-like Taste Cells

2021 ◽  
pp. JN-RM-1444-21
Author(s):  
Yuryanni A. Rodriguez ◽  
Jennifer K. Roebber ◽  
Gennady Dvoryanchikov ◽  
Vivien Makhoul ◽  
Stephen D. Roper ◽  
...  
Keyword(s):  
Taste Buds ◽  
Type I ◽  
Taste Cells

scholarly journals GAD65Cre drives reporter expression in multiple taste cell types

2021 ◽  
Author(s):  
Eric D. Larson ◽  
Aurelie Vandenbeuch ◽  
Catherine B. Anderson ◽  
Sue C. Kinnamon
Keyword(s):  
Cell Function ◽  
Cell Types ◽  
Taste Cell ◽  
Taste Buds ◽  
Specific Marker ◽  
Type I ◽  
Chorda Tympani ◽  
Type I Cells ◽  
Taste Cells ◽  
I Cells

ABSTRACTIn taste buds, Type I cells represent the majority of cells (50-60%) and primarily have a glial-like function in taste buds. However, recent studies suggest that they have additional sensory and signaling functions including amiloride-sensitive salt transduction, oxytocin modulation of taste, and substance P mediated GABA release. Nonetheless, the overall function of Type I cells in transduction and signaling remains unclear, primarily because of the lack of a reliable reporter for this cell type. GAD65 expression is specific to Type I taste cells and GAD65 has been used as a Cre driver to study Type I cells in salt taste transduction. To test the specificity of transgene-driven expression, we crossed GAD65Cre mice with floxed tdTomato and Channelrhodopsin (ChR2) lines and examined the progeny with immunochemistry, chorda tympani recording, and calcium imaging. We report that while many tdTomato+ taste cells express NTPDase2, a specific marker of Type I cells, we see expression of tdTomato in both Gustducin and SNAP25 positive taste cells. We also see ChR2 in cells just outside the fungiform taste buds. Chorda tympani recordings in the GAD65Cre/ChR2 mice show large responses to blue light, larger than any response to standard taste stimuli. Further, several isolated tdTomato positive taste cells responded to KCl depolarization with increases in intracellular calcium, indicating the presence of voltage-gated calcium channels. Taken together, these data suggest that GAD65Cre mice drive expression in multiple taste cell types and thus cannot be considered a reliable reporter of Type I cell function.

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 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.

scholarly journals Membrane currents in taste cells of the rat fungiform papilla. Evidence for two types of Ca currents and inhibition of K currents by saccharin.

1990 ◽  
Vol 96 (5) ◽  
pp. 1061-1084 ◽  
Author(s):  
P Béhé ◽  
J A DeSimone ◽  
P Avenet ◽  
B Lindemann
Keyword(s):  
Action Potentials ◽  
Basolateral Membrane ◽  
Cell Voltage ◽  
Taste Buds ◽  
Peak Amplitude ◽  
Fungiform Papilla ◽  
Whole Cell ◽  
Inward Current ◽  
Taste Cells ◽  
K Currents

Taste buds were isolated from the fungiform papilla of the rat tongue and the receptor cells (TRCs) were patch clamped. Seals were obtained on the basolateral membrane of 281 TRCs, protruding from the intact taste buds or isolated by micro-dissection. In whole-cell configuration 72% of the cells had a TTX blockable transient Na inward current (mean peak amplitude 0.74 nA). All cells had outward K currents. Their activation was slower than for the Na current and a slow inactivation was also noticeable. The K currents were blocked by tetraethylammonium, Ba, and 4-aminopyridine, and were absent when the pipette contained Cs instead of K. With 100 mM Ba or 100 mM Ca in the bath, two types of inward current were observed. An L-type Ca current (ICaL) activated at -20 mV had a mean peak amplitude of 440 pA and inactivated very slowly. At 3 mM Ca the activation threshold of ICaL was near -40 mV. A transient T-type current (ICaT) activated at -50 mV had an average peak amplitude of 53 pA and inactivated with a time constant of 36 ms at -30 mV. ICaL was blocked more efficiently by Cd and D600 than ICaT. ICaT was blocked by 0.2 mM Ni and half blocked by 200 microM amiloride. In whole-cell voltage clamp, Na-saccharin caused (in 34% of 55 cells tested) a decrease in outward K currents by 21%, which may be expected to depolarize the TRCs. Also, Na-saccharin caused some taste cells to fire action potentials (on-cell, 7 out of 24 cells; whole-cell, 2 out of 38 cells responding to saccharin) of amplitudes sufficient to activate ICaL. Thus the action potentials will cause Ca inflow, which may trigger release of transmitter.

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 subset of broadly responsive Type III taste cells contribute to the detection of bitter, sweet and umami stimuli

2019 ◽  
Author(s):  
Debarghya Dutta Banik ◽  
Eric D. Benfey ◽  
Laura E. Martin ◽  
Kristen E. Kay ◽  
Gregory C. Loney ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
Taste Receptor ◽  
Live Cell ◽  
Type I ◽  
Type Ii Cells ◽  
Type Ii ◽  
Type Iii ◽  
Umami Taste ◽  
Taste Cells ◽  
Multiple Signaling

ABSTRACTTaste receptor cells use multiple signaling pathways to detect chemicals in potential food items. These cells are functionally grouped into different types: Type I cells act as support cells and have glial-like properties; Type II cells detect bitter, sweet, and umami taste stimuli; and Type III cells detect sour and salty stimuli. We have identified a new population of taste cells that are broadly tuned to multiple taste stimuli including bitter, sweet, sour and umami. The goal of this study was to characterize these broadly responsive (BR) taste cells. We used an IP3R3-KO mouse (does not release calcium (Ca2+) from Type II cells when stimulated with bitter, sweet or umami stimuli) to characterize the BR cells without any potentially confounding input from Type II cells. Using live cell Ca2+ imaging in isolated taste cells from the IP3R3-KO mouse, we found that BR cells are a subset of Type III cells that respond to sour stimuli but also use a PLCβ3 signaling pathway to respond to bitter, sweet and umami stimuli. Unlike Type II cells, individual BR cells are broadly tuned and respond to multiple stimuli across different taste modalities. Live cell imaging in a PLCβ3-KO mouse confirmed that BR cells use a PLCβ3 signaling pathway to generate Ca2+ signals to bitter, sweet and umami stimuli. Analysis of c-Fos activity in the nucleus of the solitary tract (NTS) and short term behavioral assays revealed that BR cells make significant contributions to taste.

Freeze-substitution and Postembedding Immunocytochemistry on Rat Taste Buds: G-Proteins, Calcitonin Gene-related Peptide, and Choline Acetyl Transferase

1997 ◽  
Vol 3 (1) ◽  
pp. 53-69 ◽  
Author(s):  
Bert Ph.M. Menco ◽  
Maya P. Yankova ◽  
Sidney A. Simon
Keyword(s):  
Freeze Substitution ◽  
Taste Buds ◽  
Taste Bud ◽  
Type I ◽  
Type Ii ◽  
Choline Acetyl Transferase ◽  
Type I Cells ◽  
Dense Core Granules ◽  
Electron Dense Core ◽  
I Cells

Abstract: We have explored freeze-substitution combined with low-temperature embedding in rat taste buds for postembedding immunocytochemistry. A major difference in taste bud cells that were rapidly frozen without prior chemical fixation and those that were fixed and cryoprotected before freezing was that electron-dense core granules were virtually absent. The antibodies used in these initial studies were directed against calcitonin gene-related peptide (CGRP), a peptide commonly found in nociceptive neurons; the α-subunits of two G-proteins involved in bitter and sweet taste transduction; and choline acetyl transferase (ChAT), an enzyme involved in the synthesis of acetylcholine. Anti-CGRP immunolabeled a subpopulation of unmyelinated perigemmal neurons; anti-Gqα labeled a larger subpopulation of these neurons and the microvilli of cells that were most likely from Type II vallate taste buds. α-Gustducin was found in cytoplasm of Type II and/or III cells and probably in microvilli of Type I cells of vallate taste buds. The best labeling results were obtained with anti-ChAT, which stained microvilli and lateral membranes of some Type II vallate taste bud cells, and the cytoplasm of some other Type II and/or III vallate cells. In addition, anti-ChAT labeled electron-opaque materials inside taste bud pores of vallate papillae, but, under the same conditions, not granules of Type I cells or most of the vesicles in von Ebner's glands. These data suggest that we can not assume a priori that the contents of the electron-dense core granules of Type I cells, or even of those of von Ebner's glands, contain the precursors of the taste bud pore–dense substances.

scholarly journals Amiloride-sensitive channels in type I fungiform taste cells in mouse

2008 ◽  
Vol 9 (1) ◽  
Author(s):  
Aurelie Vandenbeuch ◽  
Tod R Clapp ◽  
Sue C Kinnamon
Keyword(s):  
Type I ◽  
Taste Cells
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