Recovery of C-fiber-induced extravasation following peripheral nerve injury in the rat.
Peripheral nerve injury leads to substantial alterations in injured sensory neurons. These include cell death, phenotypic modifications, and regeneration. Primary sensory neurons have recently been shown not to die until a time beyond 4 months following a nerve crush or ligation and this loss is, moreover, limited to cells with unmyelinated axons, the C-fibers. The late loss of C-fibers may be due to a lack of target reinnervation during the regenerative phase. In order to investigate this, we have used a particular peripheral function, unique to C-fibers, as a measure of peripheral reinnervation: an increase in capillary permeability on antidromic activation of C-fibers, i.e., neurogenic extravasation. This was investigated in rats that had received a nerve crush injury 1 to 50 weeks earlier. Some recovery of the capacity of C-fibers to generate extravasation was detected at 8-10 weeks, which increased further at 12-14 weeks, and then plateaued at this level with no further recovery at 30 or 50 weeks. In intact and damaged sciatic nerves, A beta-fibers never induced extravasation. These findings are compatible with the hypothesis that those C-fibers which make it back to their peripheral targets do not subsequently die and those that do not, may die.
Bester
H
H
Department of Anatomy and Developmental Biology, University College London, Medawar Building, Gower Street, London, WC1E 6BT, United Kingdom.
Allchorne
A J
AJ
Woolf
C J
CJ
D000818:Animals; D019771:Axotomy; D001522:Behavior, Animal / Q000502:physiology; D016923:Cell Death / Q000502:physiology; D002463:Cell Membrane Permeability / Q000502:physiology; D004558:Electric Stimulation; D005070:Evans Blue / Q000493:pharmacokinetics; D005119:Extravasation of Diagnostic and Therapeutic Materials; D008297:Male; D009149:Mustard Plant; D009409:Nerve Crush; D009410:Nerve Degeneration / Q000503:physiopathology*; D009412:Nerve Fibers / Q000502:physiology*; D009475:Neurons, Afferent / Q000378:metabolism* / Q000648:ultrastructure; D009619:Nociceptors / Q000187:drug effects / Q000502:physiology; D010146:Pain / Q000503:physiopathology*; D010812:Physical Stimulation; D010936:Plant Extracts / Q000494:pharmacology; D010938:Plant Oils; D051381:Rats; D017207:Rats, Sprague-Dawley; D012584:Sciatic Nerve / Q000166:cytology / Q000293:injuries* / Q000378:metabolism
D010936:Plant Extracts; D010938:Plant Oils; D005070:Evans Blue; C027793:mustard oil