5-HT3 receptor binding sites are on capsaicin-sensitive fibres in the rat spinal cord

Eur J Pharmacol. 1989 May 19;164(2):315-22. doi: 10.1016/0014-2999(89)90472-x.


Specific binding sites for [3H]zacopride were found in the dorsal part of the rat spinal cord, particularly in the superficial layers of the dorsal horn. These binding sites had the same pharmacological profile as 5-HT3 receptors in membranes from the rat entorhinal cortex or from NG 108-15 neuroblastoma-glioma cells. Administration of capsaicin (50 mg/kg s.c.) to neonatal rats to induce degeneration of unmyelinated primary sensory fibres resulted in a significant decrease in [3H]zacopride specific binding (-50%) in the dorsal zone of the spinal cord of 4 month-old rats. This decrease was as pronounced as the decrease in [3H]bremazocine and [3H]naloxone binding to opiate receptors. These data support the presynaptic location of 5-HT3 receptors, at least in part, on capsaicin-sensitive primary afferent fibres in the rat spinal cord.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Animals, Newborn / metabolism
  • Antiemetics / metabolism
  • Autoradiography
  • Benzamides / metabolism
  • Benzomorphans / metabolism
  • Bridged Bicyclo Compounds / metabolism
  • Bridged Bicyclo Compounds, Heterocyclic*
  • Capsaicin / pharmacology*
  • Male
  • Naloxone / metabolism
  • Nerve Tissue Proteins / metabolism
  • Neurons / drug effects*
  • Neurons / metabolism
  • Rats
  • Rats, Inbred Strains
  • Receptors, Serotonin / drug effects*
  • Receptors, Serotonin / metabolism
  • Spinal Cord / cytology
  • Spinal Cord / drug effects*
  • Spinal Cord / metabolism


  • Antiemetics
  • Benzamides
  • Benzomorphans
  • Bridged Bicyclo Compounds
  • Bridged Bicyclo Compounds, Heterocyclic
  • Nerve Tissue Proteins
  • Receptors, Serotonin
  • Naloxone
  • zacopride
  • bremazocine
  • Capsaicin