The role of the anion in salt (NaCl) detection by mouse taste buds

Jennifer K. Roebber, Stephen D. Roper, Nirupa Chaudhari

Research output: Contribution to journalArticlepeer-review

24 Scopus citations

Abstract

How taste buds detect NaCl remains poorly understood. Among other problems, applying taste-relevant concentrations of NaCl (50 –500 mM) onto isolated taste buds or cells exposes them to unphysiological (hypo/hypertonic) conditions. To overcome these limitations, we used the anterior tongue of male and female mice to implement a slice preparation in which fungiform taste buds are in a relatively intact tissue environment and stimuli are limited to the taste pore. Taste-evoked responses were monitored using confocal Ca 2 imaging via GCaMP3 expressed in Type 2 and Type 3 taste bud cells. NaCl evoked intracellular mobilization of Ca 2 in the apical tips of a subset of taste cells. The concentration dependence and rapid adaptation of NaCl-evoked cellular responses closely resembled behavioral and afferent nerve responses to NaCl. Importantly, taste cell responses were not inhibited by the diuretic, amiloride. Post hoc immunostaining revealed that 80% of NaCl-responsive taste bud cells were of Type 2. Many NaCl-responsive cells were also sensitive to stimuli that activate Type 2 cells but never to stimuli for Type 3 cells. Ion substitutions revealed that amiloride-insensitive NaCl responses depended on Cl rather than Na . Moreover, choline chloride, an established salt taste enhancer, was equally effective a stimulus as sodium chloride. Although the apical transducer for Cl remains unknown, blocking known chloride channels and cotransporters had little effect on NaCl responses. Together, our data suggest that chloride, an essential nutrient, is a key determinant of taste transduction for amiloride-insensitive salt taste.

Original languageEnglish (US)
Pages (from-to)6224-6232
Number of pages9
JournalJournal of Neuroscience
Volume39
Issue number32
DOIs
StatePublished - Aug 7 2019

Keywords

  • Amiloride
  • Ca imaging
  • Fungiform taste bud
  • NaCl
  • Sensory transduction
  • Taste

ASJC Scopus subject areas

  • Neuroscience(all)

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