title: Expression of calcium-activated chloride channels Ano1 and Ano2 in mouse taste cells.
abstract: Specialized Ca(2+)-dependent ion channels ubiquitously couple intracellular Ca(2+) signals to a change in cell polarization. The existing physiological evidence suggests that Ca(2+)-activated Cl(-) channels (CaCCs) are functional in taste cells. Because Ano1 and Ano2 encode channel proteins that form CaCCs in a variety of cells, we analyzed their expression in mouse taste cells. Transcripts for Ano1 and Ano2 were detected in circumvallate (CV) papillae, and their expression in taste cells was confirmed using immunohistochemistry. When dialyzed with CsCl, taste cells of the type III exhibited no ion currents dependent on cytosolic Ca(2+). Large Ca(2+)-gated currents mediated by TRPM5 were elicited in type II cells by Ca(2+) uncaging. When TRPM5 was inhibited by triphenylphosphine oxide (TPPO), ionomycin stimulated a small but resolvable inward current that was eliminated by anion channel blockers, including T16Ainh-A01 (T16), a specific Ano1 antagonist. This suggests that CaCCs, including Ano1-like channels, are functional in type II cells. In type I cells, CaCCs were prominently active, blockable with the CaCC antagonist CaCCinh-A01 but insensitive to T16. By profiling Ano1 and Ano2 expressions in individual taste cells, we revealed Ano1 transcripts in type II cells only, while Ano2 transcripts were detected in both type I and type II cells. P2Y agonists stimulated Ca(2+)-gated Cl(-) currents in type I cells. Thus, CaCCs, possibly formed by Ano2, serve as effectors downstream of P2Y receptors in type I cells. While the role for TRPM5 in taste transduction is well established, the physiological significance of expression of CaCCs in type II cells remains to be elucidated.
authors.affiliation: Institute of Cell Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia.
authors.forename: Alexander P
authors.initials: AP
authors.lastname: Cherkashin
authors.affiliation: Institute of Cell Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia.
authors.forename: Alisa S
authors.initials: AS
authors.lastname: Kolesnikova
authors.affiliation: Institute of Cell Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia.
authors.forename: Michail V
authors.initials: MV
authors.lastname: Tarasov
authors.affiliation: Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Spitalgasse 4, A-1090, Vienna, Austria.
authors.forename: Roman A
authors.initials: RA
authors.lastname: Romanov
authors.affiliation: Institute of Cell Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia.
authors.forename: Olga A
authors.initials: OA
authors.lastname: Rogachevskaja
authors.affiliation: Institute of Cell Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia.
authors.forename: Marina F
authors.initials: MF
authors.lastname: Bystrova
authors.affiliation: Institute of Cell Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia. staskolesnikov@yahoo.com.
authors.forename: Stanislav S
authors.initials: SS
authors.lastname: Kolesnikov
mesh_terms: D000200:Action Potentials; D000818:Animals; D000075369:Anoctamin-1; D000075368:Anoctamins; D016466:CHO Cells; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D018118:Chloride Channels / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D006224:Cricetinae; D003412:Cricetulus; D057809:HEK293 Cells; D006801:Humans; D051379:Mice; D058921:Purinergic P2Y Receptor Antagonists / Q000494:pharmacology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D058470:Receptors, Purinergic P2Y / Q000378:metabolism; D050053:TRPM Cation Channels / Q000037:antagonists & inhibitors / Q000378:metabolism; D013650:Taste Buds / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology
chemical_list: C531181:ANO1 protein, mouse; C532161:ANO2 protein, mouse; D000075369:Anoctamin-1; D000075368:Anoctamins; D018118:Chloride Channels; D058921:Purinergic P2Y Receptor Antagonists; D012333:RNA, Messenger; D058470:Receptors, Purinergic P2Y; D050053:TRPM Cation Channels; C498617:Trpm5 protein, mouse; D002118:Calcium
keywords: Ano1; Ano2; Ca2+-gated Cl− channels; Purinergic transduction; Taste cells