Neurokinin receptor 1-expressing spinal cord neurons in lamina I and III/IV of postnatal rats receive inputs from capsaicin sensitive fibers

Neurosci Lett. 2003 Dec 4;352(2):121-4. doi: 10.1016/j.neulet.2003.08.042.

Abstract

Dorsal horn neurons expressing receptor for substance P (SP), the neurokinin 1 (NK1) receptor, play an important role in transmission and processing of nociceptive stimuli. To identify and study these neurons in the rat spinal cord slice preparation, we used fluorescence-conjugated SP to label NK1 receptor-expressing neurons. Labeled neurons in lamina I and III/IV were patch clamped and the vanilloid receptor 1 (TRPV1) agonist, capsaicin, was applied to evoke glutamate release from central terminals of peripheral nociceptors. Capsaicin induced an increase in the frequency of miniature excitatory postsynaptic currents in 73% of lamina I and 43% of lamina III/IV neurons expressing NK1-receptor indicating that these neurons receive direct input from capsaicin and heat sensitive nociceptors.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Animals, Newborn
  • Capsaicin / pharmacology*
  • Excitatory Postsynaptic Potentials / drug effects
  • Excitatory Postsynaptic Potentials / physiology
  • In Vitro Techniques
  • Nerve Fibers / chemistry
  • Nerve Fibers / drug effects
  • Nerve Fibers / metabolism*
  • Posterior Horn Cells / chemistry
  • Posterior Horn Cells / drug effects
  • Posterior Horn Cells / metabolism*
  • Rats
  • Receptors, Neurokinin-1 / analysis
  • Receptors, Neurokinin-1 / biosynthesis*

Substances

  • Receptors, Neurokinin-1
  • Capsaicin