Selective degeneration by capsaicin of a subpopulation of primary sensory neurons in the adult rat

Neurosci Lett. 1985 Aug 30;59(2):209-14. doi: 10.1016/0304-3940(85)90201-0.


The morphological effects of systemic capsaicin treatment have been studied in adult rats. Light and electron microscopy revealed that a subpopulation of small-to-medium sized B-type primary sensory neurons, representing about 17% of the total neuronal population in the 4th lumbar spinal ganglion, underwent rapid degeneration after the administration of capsaicin. Quantitative electron microscopy demonstrated a decrease of about 45% in the number of unmyelinated axons in the saphenous nerve. Light microscopy showed extensive axon terminal degeneration in the brainstem and spinal cord confined to the central projection areas of capsaicin-sensitive afferent fibers, as has already been revealed in the newborn rat. The present results furnish evidence for a hitherto unrecognized selective neurodegenerative action of capsaicin in the adult rat.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Capsaicin / pharmacology*
  • Ganglia, Spinal / drug effects*
  • Male
  • Neurons, Afferent / drug effects
  • Rats
  • Rats, Inbred Strains


  • Capsaicin