Sodium/calcium exchangers selectively regulate calcium signaling in mouse taste receptor cells.
Taste cells use multiple signaling mechanisms to generate appropriate cellular responses to discrete taste stimuli. Some taste stimuli activate G protein coupled receptors (GPCRs) that cause calcium release from intracellular stores while other stimuli depolarize taste cells to cause calcium influx through voltage-gated calcium channels (VGCCs). While the signaling mechanisms that initiate calcium signals have been described in taste cells, the calcium clearance mechanisms (CCMs) that contribute to the termination of these signals have not been identified. In this study, we used calcium imaging to define the role of sodium-calcium exchangers (NCXs) in the termination of evoked calcium responses. We found that NCXs regulate the calcium signals that rely on calcium influx at the plasma membrane but do not significantly contribute to the calcium signals that depend on calcium release from internal stores. Our data indicate that this selective regulation of calcium signals by NCXs is due primarily to their location in the cell rather than to the differences in cytosolic calcium loads. This is the first report to define the physiological role for any of the CCMs utilized by taste cells to regulate their evoked calcium responses.
Szebenyi
Steven A
SA
Department of Biological Sciences, University at Buffalo, The State University of New York, Buffalo, New York 14260, USA.
Laskowski
Agnieszka I
AI
Medler
Kathryn F
KF
D000818:Animals; D002118:Calcium / Q000378:metabolism; D015220:Calcium Channels / Q000187:drug effects; D020013:Calcium Signaling / Q000502:physiology*; D005071:Evoked Potentials / Q000502:physiology; D066298:In Vitro Techniques; D015640:Ion Channel Gating / Q000187:drug effects; D008094:Lithium / Q000494:pharmacology; D051379:Mice; D008810:Mice, Inbred C57BL; D043562:Receptors, G-Protein-Coupled / Q000502:physiology; D012964:Sodium / Q000494:pharmacology; D019831:Sodium-Calcium Exchanger / Q000037:antagonists & inhibitors / Q000502:physiology*; D013649:Taste / Q000502:physiology*; D013650:Taste Buds / Q000502:physiology*
D015220:Calcium Channels; D043562:Receptors, G-Protein-Coupled; D019831:Sodium-Calcium Exchanger; D008094:Lithium; D012964:Sodium; D002118:Calcium
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