DEG/ENaC but not TRP channels are the major mechanoelectrical transduction channels in a C. elegans nociceptor

Neuron. 2011 Sep 8;71(5):845-57. doi: 10.1016/j.neuron.2011.06.038.

Abstract

Many nociceptors detect mechanical cues, but the ion channels responsible for mechanotransduction in these sensory neurons remain obscure. Using in vivo recordings and genetic dissection, we identified the DEG/ENaC protein, DEG-1, as the major mechanotransduction channel in ASH, a polymodal nociceptor in Caenorhabditis elegans. But DEG-1 is not the only mechanotransduction channel in ASH: loss of deg-1 revealed a minor current whose properties differ from those expected of DEG/ENaC channels. This current was independent of two TRPV channels expressed in ASH. Although loss of these TRPV channels inhibits behavioral responses to noxious stimuli, we found that both mechanoreceptor currents and potentials were essentially wild-type in TRPV mutants. We propose that ASH nociceptors rely on two genetically distinct mechanotransduction channels and that TRPV channels contribute to encoding and transmitting information. Because mammalian and insect nociceptors also coexpress DEG/ENaCs and TRPVs, the cellular functions elaborated here for these ion channels may be conserved.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amiloride / pharmacology
  • Animals
  • Animals, Genetically Modified
  • Behavior, Animal / physiology
  • Biophysical Phenomena / drug effects
  • Biophysical Phenomena / genetics
  • Biophysical Phenomena / physiology*
  • Caenorhabditis elegans
  • Caenorhabditis elegans Proteins / genetics
  • Caenorhabditis elegans Proteins / physiology*
  • Electric Stimulation / methods
  • Mechanotransduction, Cellular / genetics
  • Mechanotransduction, Cellular / physiology*
  • Membrane Potentials / drug effects
  • Membrane Potentials / genetics*
  • Membrane Proteins / genetics
  • Membrane Proteins / physiology*
  • Mutation, Missense / genetics
  • Nociceptors / metabolism*
  • Patch-Clamp Techniques / methods
  • Reaction Time / drug effects
  • Reaction Time / genetics
  • Sodium / metabolism
  • Sodium Channel Blockers / pharmacology
  • TRPC Cation Channels / metabolism*
  • Touch / physiology

Substances

  • Caenorhabditis elegans Proteins
  • Deg-1 protein, C elegans
  • Membrane Proteins
  • Sodium Channel Blockers
  • TRPC Cation Channels
  • Amiloride
  • Sodium