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

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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GAD65Cre drives reporter expression in multiple taste cell types

10.1101/2021.01.14.426727 ◽

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.

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

10.1101/660589 ◽

2019 ◽

Cited By ~ 1

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.

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

Journal of Neuroscience ◽

10.1523/jneurosci.1444-21.2021 ◽

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

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Denatonium stimulates Ca2+ signaling in taste cells of type I

Biochemistry (Moscow) Supplement Series A Membrane and Cell Biology ◽

10.1134/s1990747813020062 ◽

2013 ◽

Vol 7 (3) ◽

pp. 242-244

Author(s):

R. A. Romanov ◽

G. D. Churbanov ◽

O. A. Rogachevskaya ◽

S. S. Kolesnikov

Keyword(s):

Type I ◽

Taste Cells

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Heat-Etching with a Bullivant Type II Simple Freeze-Cleave Device

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100067522 ◽

1970 ◽

Vol 28 ◽

pp. 106-107 ◽

Cited By ~ 1

Author(s):

Ronald S. Weinstein ◽

N. Scott McNutt

Keyword(s):

New Zealand ◽

General Hospital ◽

Massachusetts General Hospital ◽

Type I ◽

Type Ii ◽

Collaborative Effort ◽

Temperature And Pressure ◽

The University

The Type I simple cold block device was described by Bullivant and Ames in 1966 and represented the product of the first successful effort to simplify the equipment required to do sophisticated freeze-cleave techniques. Bullivant, Weinstein and Someda described the Type II device which is a modification of the Type I device and was developed as a collaborative effort at the Massachusetts General Hospital and the University of Auckland, New Zealand. The modifications reduced specimen contamination and provided controlled specimen warming for heat-etching of fracture faces. We have now tested the Mass. General Hospital version of the Type II device (called the “Type II-MGH device”) on a wide variety of biological specimens and have established temperature and pressure curves for routine heat-etching with the device.

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Two Distinct Types of Microfilaments in the Cytoplasm of Human Adenohypophysial Cells

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100073787 ◽

1973 ◽

Vol 31 ◽

pp. 668-669

Author(s):

E. Horvath ◽

K. Kovacs ◽

I. E. Stratmann ◽

C. Ezrin

Keyword(s):

Pituitary Tumors ◽

Average Diameter ◽

Anterior Lobe ◽

Uranyl Acetate ◽

Type I ◽

Breast Cancer Patients ◽

Human Pituitary ◽

Severe Diabetes ◽

Pituitary Glands ◽

Membrane Bound

Surgically removed human pituitary glands as well as pituitary tumors fixed in glutaraldehyde, postfixed in osmium tetroxide, embedded in epon resin, stained with uranyl acetate and lead citrate have been investigated by electron microscopy in order to correlate ultrastructure with functional activity. In the course of this study two distinct types of microfilaments have been identified in the cytoplasm of adenohypophysiocytes.Type I microfilaments (Fig. 1) were found in the cytoplasm of anterior lobe cells of five female subjects with disseminated mammary cancer and two patients with severe diabetes mellitus. The breast cancer patients were treated pre-operatively for various periods of time with different doses of oxysteroids. The microfilaments had an average diameter of JO A, formed parallel bundles, were scattered irregularly in the cytoplasm and were frequently located in the perikaryon. They were not membrane-bound and failed to show any periodicity.

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The diagnosis of metabolic storage disease in skin biopsies (a light-, electronmicroscopic, and analytical study)

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100084119 ◽

1978 ◽

Vol 36 (2) ◽

pp. 648-649

Author(s):

W. Jurecka ◽

W. Gebhart ◽

H. Lassmann

Keyword(s):

Storage Disease ◽

Hunter Syndrome ◽

Histochemical Demonstration ◽

Sweat Glands ◽

Type I ◽

Storage Material ◽

Scheie Syndrome ◽

Storage Products ◽

Skin Biopsies ◽

Type V

Diagnosis of metabolic storage disease can be established by the determination of enzymes or storage material in blood, urine, or several tissues or by clinical parameters. Identification of the accumulated storage products is possible by biochemical analysis of isolated material, by histochemical demonstration in sections, or by ultrastructural demonstration of typical inclusion bodies. In order to determine the significance of such inclusions in human skin biopsies several types of metabolic storage disease were investigated. The following results were obtained.In MPS type I (Pfaundler-Hurler-Syndrome), type II (Hunter-Syndrome), and type V (Ullrich-Scheie-Syndrome) mainly “empty” vacuoles were found in skin fibroblasts, in Schwann cells, keratinocytes and macrophages (Dorfmann and Matalon 1972). In addition, prominent vacuolisation was found in eccrine sweat glands. The storage material could be preserved in part by fixation with cetylpyridiniumchloride and was also present within fibroblasts grown in tissue culture.

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Methionine-Specific Staining of Collagen

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010005408x ◽

1982 ◽

Vol 40 ◽

pp. 294-295

Author(s):

E.M. Kuhn ◽

K.D. Marenus ◽

M. Beer

Keyword(s):

Amino Acids ◽

Collagen Fibers ◽

Type Iii Collagen ◽

Type I ◽

Electron Microscopic ◽

Good Correspondence ◽

Specific Staining ◽

Type Iii ◽

Different Types ◽

Sulfur Containing

Fibers composed of different types of collagen cannot be differentiated by conventional electron microscopic stains. We are developing staining procedures aimed at identifying collagen fibers of different types.Pt(Gly-L-Met)Cl binds specifically to sulfur-containing amino acids. Different collagens have methionine (met) residues at somewhat different positions. A good correspondence has been reported between known met positions and Pt(GLM) bands in rat Type I SLS (collagen aggregates in which molecules lie adjacent to each other in exact register). We have confirmed this relationship in Type III collagen SLS (Fig. 1).

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