Contribution of the TRPV1 channel to salt taste quality in mice as assessed by conditioned taste aversion generalization and chorda tympani nerve responses

Kimberly R. Smith, Yada Treesukosol, A. Brennan Paedae, Robert J. Contreras, Alan C. Spector

Research output: Contribution to journalArticlepeer-review

Abstract

In rodents, at least two transduction mechanisms are involved in salt taste: 1) the sodiumselective epithelial sodium channel, blocked by topical amiloride administration, and 2) one or more amiloride-insensitive cationnonselective pathways. Whereas electrophysiological evidence from the chorda tympani nerve (CT) has implicated the transient receptor potential vanilloid-1 (TRPV1) channel as a major component of amiloride-insensitive salt taste transduction, behavioral results have provided only equivocal support. Using a brief-access taste test, we examined generalization profiles of water-deprived C57BL/6J (WT) and TRPV1 knockout (KO) mice conditioned (via LiCl injection) to avoid 100 μM amiloride-prepared 0.25 M NaCl and tested with 0.25 M NaCl, sodium gluconate, KCl, NH4Cl, 6.625 mM citric acid, 0.15 mM quinine, and 0.5 M sucrose. Both LiCl-injected WT and TRPV1 KO groups learned to avoid NaCl+amiloride relative to controls, but their generalization profiles did not differ; LiCl-injected mice avoided the nonsodium salts and quinine suggesting that a TRPV1-independent pathway contributes to the taste quality of the amiloride-insensitive portion of the NaCl signal. Repeating the experiment but doubling all stimulus concentrations revealed a difference in generalization profiles between genotypes. While both LiCl-injected groups avoided the nonsodium salts and quinine, only WT mice avoided the sodium salts and citric acid. CT responses to these stimuli and a concentration series of NaCl and KCl with and without amiloride did not differ between genotypes. Thus, in our study, TRPV1 did not appear to contribute to sodium salt perception based on gustatory signals, at least in the CT, but may have contributed to the oral somatosensory features of sodium.

Original languageEnglish (US)
Pages (from-to)R1195-R1205
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Volume303
Issue number11
DOIs
StatePublished - 2012

Keywords

  • Gustatory system
  • Sodium chloride
  • Taste transduction

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

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