title: Recovery of C-fiber-induced extravasation following peripheral nerve injury in the rat.
abstract: 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.
authors.affiliation: Department of Anatomy and Developmental Biology, University College London, Medawar Building, Gower Street, London, WC1E 6BT, United Kingdom.
authors.forename: H
authors.initials: H
authors.lastname: Bester
authors.forename: A J
authors.initials: AJ
authors.lastname: Allchorne
authors.forename: C J
authors.initials: CJ
authors.lastname: Woolf
mesh_terms: 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
chemical_list: D010936:Plant Extracts; D010938:Plant Oils; D005070:Evans Blue; C027793:mustard oil