Characterization of Chloride Currents and Their Noradrenergic Modulation in Rat Taste Receptor Cells

Herness, M. Scott; Sun, Xiaodong

doi:10.1152/jn.1999.82.1.260

Cited by 42 publications

(30 citation statements)

References 36 publications

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“…In addition, it is well established that certain transduction mechanisms involve the modulation of voltage-dependent K ϩ currents (Cummings et al, 1996;Gilbertson et al, 1997). Finally, Cl Ϫ currents seem to play a role in sensory adaptation and in efferent control by nerve terminals (Taylor and Roper, 1994;Herness and Sun, 1999). In conclusion, the increased magnitude of repolarizing currents (I K and I C l ) during development is likely to affect markedly the transduction properties of mouse taste cells.…”

Section: Membrane Excitability and Taste Transductionmentioning

confidence: 89%

“…3B). Conversely, 4,4Ј-diisothiocyanostilbene-2,2Ј-disulfonic acid (DIDS), a known Cl Ϫ conductance blocker in taste cells (Taylor and Roper, 1994;Herness and Sun, 1999), did not affect the outward currents in some cells (data not shown) or partially affected them in others (Fig. 3C).…”

Section: Functional Populations Of Taste Cells During Developmentmentioning

confidence: 90%

“…In addition to I K and I C l , Ca 2ϩ -dependent K ϩ currents and Ca 2ϩ -dependent Cl Ϫ currents have been described in rat taste cells (Chen et al, 1996;Herness and Sun, 1999). The application of a Ca 2ϩ -free Tyrode solution (containing 3 mM Mg 2ϩ ) did not affect the outward currents in mouse Na/OUT cells (n ϭ 4; data not shown).…”

Section: Development Of Voltage-dependent Currentsmentioning

confidence: 91%

“…13). It is interesting to note that in rat vallate taste cells chloride currents represent only a small portion of the outward current (Herness and Sun, 1999), whereas in mouse vallate taste buds some cells exhibit large I C l . It is likely that these differences may have a profound effect on the transduction capabilities of taste cells in mouse as compared with rat.…”

Section: Development Of Membrane Excitability In Putative Taste Sensomentioning

confidence: 99%

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Postnatal Development of Membrane Excitability in Taste Cells of the Mouse Vallate Papilla

et al. 2002

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The mammalian peripheral taste system undergoes functional changes during postnatal development. These changes could reflect age-dependent alterations in the membrane properties of taste cells, which use a vast array of ion channels for transduction mechanisms. Yet, scarce information is available on the membrane events in developing taste cells. We have addressed this issue by studying voltage-dependent Na ϩ , K ϩ , and Cl Ϫ currents (I Na , I K , and I Cl , respectively) in a subset of taste cells (the so-called "Na/OUT" cells, which are electrically excitable and thought to be sensory) from mouse vallate papilla. Voltage-dependent currents play a key role during taste transduction, especially in the generation of action potentials. Patch-clamp recordings revealed that I Na , I K , and I Cl were expressed early in postnatal development. However, only I K and I Cl densities increased significantly in developing Na/OUT cells.Consistent with the rise of I K density, we found that action potential waveform changed markedly, with an increased speed of repolarization that was accompanied by an enhanced capability of repetitive firing. In addition to membrane excitability changes in putative sensory cells, we observed a concomitant increase in the occurrence of glia-like taste cells (the so called "leaky" cells) among patched cells. Leaky cells are likely involved in dissipating the increase of extracellular K ϩ during action potential discharge in chemosensory cells. Thus, developing taste cells of the mouse vallate papilla undergo a significant electrophysiological maturation and diversification. These functional changes may have a profound impact on the transduction capabilities of taste buds during development.

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Section: Membrane Excitability and Taste Transductionmentioning

confidence: 89%

Section: Functional Populations Of Taste Cells During Developmentmentioning

confidence: 90%

Section: Development Of Voltage-dependent Currentsmentioning

confidence: 91%

Section: Development Of Membrane Excitability In Putative Taste Sensomentioning

confidence: 99%

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Postnatal Development of Membrane Excitability in Taste Cells of the Mouse Vallate Papilla

et al. 2002

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“…A number of neurotransmitters, neuropeptides, and their corresponding receptors form intricate hard-wired pathways in the bud for information processing. Some examples of cell-to-cell communication in the taste bud include serotonin (5, 6), norepinephrine (7,8), ATP (9), cholecystokinin (10), and neuropeptide Y (11). It is believed that activation of TRCs results in information processing within the bud and ultimate activation of the afferent nerve fibers.…”

mentioning

confidence: 99%

GABA expression in the mammalian taste bud functions as a route of inhibitory cell-to-cell communication

Cao

Zhao

Kolli

et al. 2009

Proc. Natl. Acad. Sci. U.S.A.

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Recent advances have underscored cell-to-cell communication as an important component of the operation of taste buds with individual taste receptor cells (TRCs) communicating with oneanother by means of a number of neurotransmitters and neuropeptides, although functional roles are not yet understood. Here, we characterize the presence, distribution pattern, phenotype, and functional consequences of a previously undescribed inhibitory route within the taste bud mediated by the classic neurotransmitter GABA and its receptors. By using immunocytochemistry, subsets of TRCs within rat taste buds were identified as expressing GABA, and its synthetic enzyme glutamate decarboxylase (GAD). GAD expression was verified with Western blotting. Immunofluorescent studies revealed complex coexpression patterns of GAD with the TRC protein markers gustducin, neural cell adhesion molecule, protein gene product 9.5, and synaptosomal-associated protein of 25 kDa that collectively outline hardwired signaling pathways of GABAergic TRCs. RT-PCR and immunocytochemistry demonstrated that both GABA A and GABAB receptors are expressed in the taste bud. The later was observed in a subset TRCs paracrine to GAD-expressing TRCs. Physiological effects of GABA were examined by patch clamp recordings. GABA and the GABAA agonists muscimol and isoguvacine enhanced isolated chloride currents in a dose-dependent manner. Also, GABA and the GABAB agonist baclofen both elicited increases of the inwardly rectifying potassium currents that could be blocked by the GABAB receptor antagonist CGP 35348 and the G protein blocker GDP-␤S. Collectively, these data suggest that GABAergic TRCs are able to shape the final chemosensory output of the bud by means of processes of cell-to-cell modulation.gustation ͉ neuromodulation ͉ neurotransmitters ͉ transduction ͉ paracrine signaling R ecent studies of gustatory transduction (1, 2) have dramatically altered our understanding of how the taste bud operates. Early views of taste-bud function were based on anatomical studies and classified taste receptor cells (TRCs) into types I, II, or III. Type III cells are synaptically connected to afferent nerve fibers and were considered as ''true'' receptor cells, because they communicate directly with the central nervous system. Types I and II, differing in their opacity (dark or light, respectively) lack synapses, and were considered supportive cells. The discovery of the 7 transmembrane receptor families T1R and T2R and other downstream signaling molecules in type II cells changed the view that single TRCs operate in isolation but instead function collectively through cell-to-cell communication in producing the neural output (3, 4). The notion has lead to discussing transduction as early, or primary, events leading to activation of late, or secondary, events. Early events involve steps leading to the activation (i.e., depolarization) of an individual TRC. Tastant molecules interact with receptors of the T1R or T2R families in type II cells or with ion channels such as the trp...

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Gambierol

Sasaki¹,

Cagide²,

Louzao³

2007

Phycotoxins: Chemistry and Biochemistry

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Characterization of Chloride Currents and Their Noradrenergic Modulation in Rat Taste Receptor Cells

Cited by 42 publications

References 36 publications

Postnatal Development of Membrane Excitability in Taste Cells of the Mouse Vallate Papilla

Postnatal Development of Membrane Excitability in Taste Cells of the Mouse Vallate Papilla

GABA expression in the mammalian taste bud functions as a route of inhibitory cell-to-cell communication

Gambierol

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