Cells in laminae III and IV of the rat spinal cord which possess the neurokinin-1 receptor receive monosynaptic input from myelinated primary afferents

Eur J Neurosci. 1998 Sep;10(9):3012-9. doi: 10.1111/j.1460-9568.1998.00335.x.


We have previously demonstrated that neurons which have cell bodies in laminae III or IV of the rat spinal cord, dendrites that enter the superficial laminae and which possess the neurokinin-1 receptor receive a major synaptic input from substance P-containing primary afferent axons. In this study we set out to determine whether these cells also receive monosynaptic input from myelinated primary afferents by using transganglionic transport of the B subunit of cholera toxin to identify the central terminals of myelinated afferents from the sciatic nerve. Dual-immunofluorescence and confocal microscopy revealed apparent contacts between labelled primary afferent terminals and all of the neurokinin-1 receptor-immunoreactive cells examined, although these contacts were much less numerous than those which the cells receive from substance P-containing primary afferents. By using a combined confocal and electron microscopic technique we were able to confirm that synapses were present at some of the contacts between primary afferents and neurokinin-1 receptor-immunoreactive neurons. These results suggest that cells of this type will have wide-dynamic range receptive fields, but with a relatively strong input from nociceptors.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cholera Toxin / analysis
  • Cholera Toxin / pharmacology
  • Male
  • Microscopy, Confocal
  • Microscopy, Electron
  • Myelin Sheath / physiology*
  • Myelin Sheath / ultrastructure
  • Neurons, Afferent / physiology*
  • Neurons, Afferent / ultrastructure
  • Rats
  • Receptors, Neurokinin-1 / physiology*
  • Receptors, Neurokinin-1 / ultrastructure
  • Spinal Cord / metabolism*
  • Spinal Cord / physiology
  • Spinal Cord / ultrastructure
  • Synapses / physiology*
  • Synapses / ultrastructure


  • Receptors, Neurokinin-1
  • Cholera Toxin