Resection of sciatic nerve re-triggers central sprouting of A-fibre primary afferents in the rat.
We have investigated whether nerve injury or target deprivation is responsible for the injury induced central sprouting of A-fibres. Cholera toxin B subunit conjugated horseradish peroxidase was used to trace the termination of A-fibre primary afferents. Transection of the sciatic nerve induces central sprouting of sciatic myelinated A-fibre primary afferents into the spinal dorsal horn lamina II, which normally is the termination site of unmyelinated C-fibre primary afferents. The sprouting A-fibre terminals withdrew from lamina II after six to eight months. A second cut to the previously sectioned and ligated sciatic nerve re-triggered the central sprouting of A-fibre primary afferents into the spinal dorsal horn lamina II, suggesting that nerve injury per se rather than the deprivation of target tissues is the cause of central sprouting of A-fibre primary afferents.
Ma
Q P
QP
Department of Anatomy and Developmental Biology, University College London, Gower Street, WC1E 6BT, London, UK. qingping_ma@merck.com
Tian
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L
Woolf
C J
CJ
D000818:Animals; D007278:Injections, Spinal; D008297:Male; D009410:Nerve Degeneration / Q000378:metabolism / Q000473:pathology; D009413:Nerve Fibers, Myelinated / Q000502:physiology*; D009416:Nerve Regeneration / Q000502:physiology*; D009475:Neurons, Afferent / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012584:Sciatic Nerve / Q000502:physiology*; D013116:Spinal Cord / Q000502:physiology; D013194:Staining and Labeling