Acid-sensing ion channel-2 is not necessary for sour taste in mice.
The acid-sensitive cation channel acid-sensing ion channel-2 (ASIC2) is widely believed to be a receptor for acid (sour) taste in mammals on the basis of its physiological properties and expression in rat taste bud cells. Using reverse transcriptase-PCR, we detected expression of ASIC1 and ASIC3, but not ASIC4, in mouse and rat taste buds and nonsensory lingual epithelium. Surprisingly, we did not detect mRNA for ASIC2 in mouse taste buds, although we readily observed its expression in rat taste buds. Furthermore, in Ca2+ imaging experiments, ASIC2 knock-out mice exhibited normal physiological responses (increases in intracellular Ca2+ concentrations) to acid taste stimuli. Our results indicate that ASIC2 is not required for acid taste in mice, and that if a universal mammalian acid taste transduction mechanism exists, it likely uses other acid-sensitive receptors or ion channels.
Richter
Trevor A
TA
Department of Physiology and Biophysics, University of Miami School of Medicine, Miami, Florida 33136, USA.
Dvoryanchikov
Gennady A
GA
Roper
Stephen D
SD
Chaudhari
Nirupa
N
D062565:Acid Sensing Ion Channels; D000818:Animals; D002118:Calcium / Q000378:metabolism; D020013:Calcium Signaling / Q000502:physiology; D062626:Degenerin Sodium Channels; D004847:Epithelial Cells / Q000378:metabolism; D053503:Epithelial Sodium Channels; D066298:In Vitro Techniques; D007473:Ion Channels / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D008565:Membrane Proteins; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015222:Sodium Channels; D013268:Stimulation, Chemical; D013649:Taste / Q000235:genetics / Q000502:physiology*; D013650:Taste Buds / Q000166:cytology / Q000378:metabolism*
C568267:ASIC1 protein, mouse; C568265:ASIC2 protein, mouse; C568269:ASIC3 protein, rat; D062565:Acid Sensing Ion Channels; C568268:Asic1 protein, rat; C568425:Asic2 protein, rat; D062626:Degenerin Sodium Channels; D053503:Epithelial Sodium Channels; D007473:Ion Channels; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D012333:RNA, Messenger; D015222:Sodium Channels; D002118:Calcium