Regular Article
Diversity of Expression of the Sensory Neuron-Specific TTX-Resistant Voltage-Gated Sodium Ion Channels SNS and SNS2

https://doi.org/10.1006/mcne.1999.0828Get rights and content

Abstract

The differential distribution of two tetrodotoxin resistant (TTXr) voltage-gated sodium channels SNS (PN3) and SNS2 (NaN) in rat primary sensory neurons has been investigated. Both channels are sensory neuron specific with SNS2 restricted entirely to those small dorsal root ganglion (DRG) cells with unmyelinated axons (C-fibers). SNS, in contrast, is expressed both in small C-fiber DRG cells and in 10% of cells with myelinated axons (A-fibers). All SNS expressing A-fiber cells are Trk-A positive and many express the vanilloid-like receptor VRL1. About half of C-fiber DRG neurons express either SNS or SNS2, and in most, the channels are colocalized. SNS and SNS2 are found both in NGF-responsive and GDNF-responsive C-fibersand many of these cells also express the capsaicin receptor VR1. A very small proportion of small DRG cells express either only SNS or only SNS2. At least four different classes of A- and C-fiber DRG neurons exist, therefore, with respect to expression of these sodium channels.

References (39)

  • A.N. Akopian et al.

    A tetrodotoxin-resistant voltage-gated sodium channel expressed by sensory neurons

    Nature

    (1996)
  • A.N. Akopian et al.

    The tetrodotoxin-resistant sodium channel SNS has a specialized function in pain pathways

    Nat. Neurosci.

    (1999)
  • M.J. Caterina et al.

    A capsaicin-receptor homologue with a high threshold for noxious heat

    Nature

    (1999)
  • M.J. Caterina et al.

    The capsaicin receptor: A heat-activated ion channel in the pain pathway

    Nature

    (1997)
  • W.A. Catterall

    Cellular and molecular biology of voltage-gated sodium channels

    Physiol. Rev.

    (1992)
  • T.R. Cummins et al.

    Downregulation of tetrodotoxin-resistant sodium currents and upregulation of a rapidly repriming tetrodotoxin-sensitive sodium current in small spinal sensory neurons after nerve injury

    J. Neurosci.

    (1997)
  • S. Dib-Hajj et al.

    NaN, a novel voltage-gated Na channel, is expressed preferentially in peripheral sensory neurons and down-regulated after axotomy

    Proc. Natl. Acad. Sci. USA

    (1998)
  • T. Dryberg et al.

    Peptides as antigens. Importance of orientation

    J. Exp. Med.

    (1986)
  • A.A. Elliott et al.

    Characterization of TTX-sensitive and TTX-resistant sodium currents in small cells from adult rat dorsal root ganglia

    J. Physiol. (London)

    (1993)
  • Cited by (0)

    1

    Contributed equally.

    2

    To whom correspondence and reprint requests should be addressed. Fax: (617) 724 3632. E-mail: [email protected].

    View full text