Selective degeneration by capsaicin of a subpopulation of primary sensory neurons in the adult rat.
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.
D000818:Animals; D002211:Capsaicin / Q000494:pharmacology*; D005727:Ganglia, Spinal / Q000187:drug effects*; D008297:Male; D009475:Neurons, Afferent / Q000187:drug effects; D051381:Rats; D011919:Rats, Inbred Strains
D002211:Capsaicin