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Role of T-type calcium current in identified D-hair mechanoreceptor neurons studied in vitro

Authors

  • A.S. Dubreuil
  • H. Boukhaddaoui
  • G. Desmadryl
  • C. Martinez-Salgado
  • R. Moshourab
  • G.R. Lewin
  • P. Carroll
  • J. Valmier
  • F. Scamps

Journal

  • Journal of Neuroscience

Citation

  • J Neurosci 24 (39): 8480-8484

Abstract

  • Different subsets of dorsal root ganglion (DRG) mechanoreceptors transduce low- and high-intensity mechanical stimuli. It was shown recently that, in vivo, neurotrophin-4 (NT-4)-dependent D-hair mechanoreceptors specifically express a voltage-activated T-type calcium channel (Ca(v)3.2) that may be required for their mechanoreceptive function. Here we show that D-hair mechanoreceptors can be identified in vitro by a rosette-like morphology in the presence of NT-4 and that these rosette neurons are almost all absent in DRG cultures taken from NT-4 knock-out mice. In vitro identification of the D-hair mechanoreceptor allowed us to explore the electrophysiological properties of these cells. We demonstrate that the T-type Ca(v)3.2 channel induced slow membrane depolarization that contributes to lower the voltage threshold for action potential generation and controls spike latency after stimulation of D-hair mechanoreceptors. Indeed, the properties of the T-type amplifier are particularly well suited to explain the high sensitivity of D-hair mechanoreceptors to slowly moving stimuli.


DOI

doi:10.1523/JNEUROSCI.1598-04.2004