Expression and coexpression of Trk receptors in subpopulations of adult primary sensory neurons projecting to identified peripheral targets

Neuron. 1994 May;12(5):1161-71. doi: 10.1016/0896-6273(94)90323-9.


To determine whether neurotrophins act on functionally distinct populations of adult sensory neurons, the distributions of mRNAs for TrkA and tyrosine kinase-containing isoforms of TrkB and TrkC were determined in rat DRG neurons projecting to different peripheral targets. Whereas trkA was expressed by a very high percentage of visceral afferents, trkC was expressed frequently only in muscle afferents. Among cutaneous afferents, the size distributions for trkA- and trkC-positive cells showed little overlap. The percentages and size distributions of cells labeled for the trks argue strongly that almost all trkB-expressing cells must also express trkA or trkC. These results indicate that NGF and NT-3 act on functionally distinct populations of adult sensory neurons and suggest that a sizeable number of small DRG neurons may not respond to neurotrophins via a known Trk in the adult rat.

MeSH terms

  • Afferent Pathways / metabolism
  • Aging / metabolism
  • Animals
  • Axonal Transport
  • Female
  • Ganglia, Spinal / cytology
  • Ganglia, Spinal / growth & development
  • Ganglia, Spinal / metabolism*
  • Gene Expression*
  • In Situ Hybridization
  • Male
  • Neurons, Afferent / cytology
  • Neurons, Afferent / metabolism*
  • Protein-Tyrosine Kinases / biosynthesis
  • Proto-Oncogene Proteins / biosynthesis*
  • RNA, Messenger / biosynthesis
  • Rats
  • Receptor Protein-Tyrosine Kinases / biosynthesis*
  • Receptor, trkA
  • Receptor, trkB
  • Receptor, trkC
  • Receptors, Growth Factor / biosynthesis*
  • Receptors, Nerve Growth Factor / biosynthesis*
  • Skin / innervation


  • Proto-Oncogene Proteins
  • RNA, Messenger
  • Receptors, Growth Factor
  • Receptors, Nerve Growth Factor
  • Protein-Tyrosine Kinases
  • Receptor Protein-Tyrosine Kinases
  • Receptor, trkA
  • Receptor, trkB
  • Receptor, trkC