Morphologic characterization of rat taste receptor cells that express components of the phospholipase C signaling pathway

  title={Morphologic characterization of rat taste receptor cells that express components of the phospholipase C signaling pathway},
  author={Tod Clapp and Ruibiao Yang and Cristi L. Stoick and Sue C. Kinnamon and John C. Kinnamon},
  journal={Journal of Comparative Neurology},
Rat taste buds contain three morphologically distinct cell types that are candidates for taste transduction. The physiologic roles of these cells are, however, not clear. Inositol 1,4,5‐triphosphate (IP3) has been implicated as an important second messenger in bitter, sweet, and umami taste transductions. Previously, we identified the type III IP3 receptor (IP3R3) as the dominant isoform in taste receptor cells. In addition, a recent study showed that phospholipase Cβ2 (PLCβ2) is essential for… 
Separate Populations of Receptor Cells and Presynaptic Cells in Mouse Taste Buds
Functional calcium imaging and single-cell reverse transcription (RT)-PCR demonstrate the existence of at least two molecularly distinct functional classes of taste cells: receptor cells and synapse-forming cells.
Taste cell types and transduction
GFP­labeled Type III cells exhibit voltage­ and Ca2+­ dependent increases in capacitance, suggesting vesicular release of transmitter, and are not obligatory intermediates between Type II cells and nerve fibers.
Evidence for two populations of bitter responsive taste cells in mice.
Analysis of dual responsive cells found that bitter responses were inhibited by the PLC inhibitor U73122, and Immunocytochemical analysis detected PLCbeta3 and IP(3)R1, indicating the presence of multiple PLC signaling pathways in taste cells.
Immunohistochemical localization of cystic fibrosis transmembrane regulator and clara cell secretory protein in taste receptor cells of rat circumvallate papillae.
The results showed that secretory markers such as CFTR, CC10, and CC26 are present in taste cells of rat circumvallate papillae, and their immunoreactivity is expressed, to a different extent, in subsets of taste cells that express alpha-gustducin.
TRPM5, a taste-signaling transient receptor potential ion-channel, is a ubiquitous signaling component in chemosensory cells
TRPM5 is considered to be an intrinsic signaling component of mammalian chemosensory organs, and its expression in rat and mouse tissues is investigated to provide evidence for brush cells being an important cellular correlate in the periphery.
Functional expression of the extracellular-Ca2+-sensing receptor in mouse taste cells
The results indicate that type III cells can serve a novel chemosensory function by expressing the polymodal receptor CASR and identify transcripts for both receptors in type I cells, no transcripts in type II cells and only CASR transcripts intype III cells, by using the SMART-PCR RNA amplification method.
Selective expression of muscarinic acetylcholine receptor subtype M3 by mouse type III taste bud cells
It is found that M3 is expressed by type III TBCs, which is the only cell type that possesses synaptic contacts with taste nerve fibers in taste buds and the results suggest that type III cells respond to ACh and release Ca2+ from intracellular stores.
Gustatory sensory cells express a receptor responsive to protein breakdown products (GPR92)
Results indicate that umami cells may respond not only to amino acids but also to peptides in protein hydrolysates, suggesting that protein breakdown products may contribute to umami taste.
Faithful expression of GFP from the PLCbeta2 promoter in a functional class of taste receptor cells.
Transgenic mice expressing green fluorescent protein (GFP) under the control of the PLCbeta2 promoter-GFP transgenic lines promise to be useful for studying taste transduction, sensory signal processing, and taste bud development.
Development of Full Sweet, Umami, and Bitter Taste Responsiveness Requires Regulator of G protein Signaling-21 (RGS21)
Reduced tastant-mediated responses and behaviors exhibited by adult mice lacking Rgs21 expression since birth have revealed an underappreciated requirement for a GPCR GAP to establish the full character of tastant signaling.


Immunocytochemical evidence for co-expression of Type III IP3 receptor with signaling components of bitter taste transduction
IP3R3 is the dominant form of the IP3 receptor expressed in taste cells and the data suggest it plays an important role in bitter taste transduction.
A transient receptor potential channel expressed in taste receptor cells
Heterologous expression studies of Trpm5 indicate that it functions as a cationic channel that is gated when internal calcium stores are depleted, and may be responsible for capacitative calcium entry in taste receptor cells that respond to bitter and/or sweet compounds.
IP(3) receptor type 3 and PLCbeta2 are co-expressed with taste receptors T1R and T2R in rat taste bud cells.
Findings indicate that PLCbeta2 and IP(3)R3 co-localize together with G(i2) as downstream components of two different types of taste receptors, T1R and T2R, in taste bud cells.
Electrophysiological Characterization of Voltage-Gated Currents in Defined Taste Cell Types of Mice
Taste cells isolated from mouse vallate and foliate papillae are used to characterize voltage-gated currents in the three principal elongate types of taste cells: type I, II, and III, suggesting that these cells use mechanisms other than classical synapses to communicate signals to the brain.
A Plethora of Taste Receptors
Changes in IP3 and cytosolic Ca2+ in response to sugars and non‐sugar sweeteners in transduction of sweet taste in the rat.
A sweet‐sensitive cell of the rat responds to sucrose with an increase in cAMP and Ca2+ uptake, but to non‐sugar sweeteners with a increase in IP3 and Ca1+ release, indicating multiple pathways of Ca2- uptake activated by cAMP.
Taste receptor cell responses to the bitter stimulus denatonium involve Ca2+ influx via store-operated channels.
It is reported here that prolonged exposure to denatonium induces sustained increases in [Ca2+]i that are dependent on Ca2+ influx, and that SOCs may contribute to bitter taste transduction and to regulation of Ca 2+ homeostasis in taste cells.
Acetylcholine increases intracellular Ca2+ in taste cells via activation of muscarinic receptors.
  • T. Ogura
  • Biology
    Journal of neurophysiology
  • 2002
The results suggest that ACh binds to M1/M3/M5-like subtypes of muscarinic ACh receptors, causing an increase in inositol 1,4,5-trisphosphate and subsequent release of Ca2+ from the intracellular stores.
Localization of serotonin in taste buds: A comparative study in four vertebrates
It is postulate that serotonin functions as a neuromodulator or neurotransmitter in vertebrate taste buds and that taste cells can take up 5‐HTP and convert it to serotonin.
Localization of the glutamate–aspartate transporter, GLAST, in rat taste buds
It is proposed that these GLAST‐positive cells play a glia‐like role in the uptake of glutamate following its release at synapses within the taste bud although the precise location of the latter remains uncertain.