Arachidonic acid can function as a signaling modulator by activating the TRPM5 cation channel in taste receptor cells

Hideaki Oike, Minoru Wakamori, Yasuo Mori, Hiroki Nakanishi, Ryo Taguchi, Takumi Misaka, Ichiro Matsumoto, Keiko Abe

Research output: Contribution to journalArticlepeer-review

50 Citations (Scopus)

Abstract

Vertebrate sensory cells such as vomeronasal neurons and Drosophila photoreceptor cells use TRP channels to respond to exogenous stimuli. In mammalian taste cells, bitter and sweet substances as well as some amino acids are received by G protein-coupled receptors (T2Rs or T1Rs). As a result of activation of G protein and phospholipase Cβ2, the TRPM5 channel is activated. Intracellular Ca2+ is known to be a TRPM5 activator, but the participation of lipid activators remains unreported. To clarify the effect of arachidonic acid on TRPM5 in taste cells, we investigated the expression profile of a series of enzymes involved in controlling the intracellular free arachidonic acid level, with the result that in a subset of taste bud cells, monoglyceride lipase (MGL) and cyclooxygenase-2 (COX-2) are expressed as well as the previously reported group IIA phospholipase A2 (PLA2-IIA). Double-labeling analysis revealed that MGL, COX-2 and PLA2-IIA are co-expressed in some cells that express TRPM5. We then investigated whether arachidonic acid activates TRPM5 via a heterologous expression system in HEK293 cells, and found that its activation occurred at 10 μM arachidonic acid. These results strongly suggest the possibility that arachidonic acid acts as a modulator of TRPM5 in taste signaling pathways.

Original languageEnglish
Pages (from-to)1078-1084
Number of pages7
JournalBiochimica et Biophysica Acta - Molecular and Cell Biology of Lipids
Volume1761
Issue number9
DOIs
Publication statusPublished - 2006 Sep
Externally publishedYes

Keywords

  • Arachidonic acid
  • Cyclooxygenase
  • Monoglyceride lipase
  • Phospholipase A
  • TRPM5
  • Taste signaling

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology

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