Polyunsaturated fatty acids activate the Drosophila light-sensitive channels TRP and TRPL

Nature. 1999 Jan 21;397(6716):255-9. doi: 10.1038/16703.


Phototransduction in invertebrate microvillar photoreceptors is thought to be mediated by the activation of phospholipase C (PLC), but how this leads to gating of the light-sensitive channels is unknown. Most attention has focused on inositol-1,4,5-trisphosphate, a second messenger produced by PLC from phosphatidylinositol-4,5-bisphosphate; however, PLC also generates diacylglycerol, a potential precursor for several polyunsaturated fatty acids, such as arachidonic acid and linolenic acid. Here we show that both of these fatty acids reversibly activate native light-sensitive channels (transient receptor potential (TRP) and TRP-like (TRPL)) in Drosophila photoreceptors as well as recombinant TRPL channels expressed in Drosophila S2 cells. Recombinant channels are activated rapidly in both whole-cell recordings and inside-out patches, with a half-maximal effector concentration for linolenic acid of approximately 10 microM. Four different lipoxygenase inhibitors, which might be expected to lead to build-up of endogenous fatty acids, also activate native TRP and TRPL channels in intact photoreceptors. As arachidonic acid may not be found in Drosophila, we suggest that another polyunsaturated fatty acid, such as linolenic acid, may be a messenger of excitation in Drosophila photoreceptors.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Arachidonic Acid / physiology
  • Calcium Channels / physiology*
  • Calmodulin-Binding Proteins / physiology*
  • Cells, Cultured
  • Drosophila Proteins*
  • Drosophila melanogaster
  • Fatty Acids, Unsaturated / physiology*
  • Insect Proteins / physiology*
  • Ion Channels / physiology
  • Light
  • Linoleic Acid / physiology
  • Lipoxygenase Inhibitors / pharmacology
  • Membrane Proteins / physiology*
  • Photoreceptor Cells, Invertebrate / physiology*
  • Transient Receptor Potential Channels
  • Vision, Ocular
  • alpha-Linolenic Acid / physiology


  • Calcium Channels
  • Calmodulin-Binding Proteins
  • Drosophila Proteins
  • Fatty Acids, Unsaturated
  • Insect Proteins
  • Ion Channels
  • Lipoxygenase Inhibitors
  • Membrane Proteins
  • Transient Receptor Potential Channels
  • trp protein, Drosophila
  • trpl protein, Drosophila
  • alpha-Linolenic Acid
  • Arachidonic Acid
  • Linoleic Acid