title: The consequences of microneurography electrode-induced injury of peripheral nerves observed in the rat and man.
abstract: The consequences of microneurography were assessed, using tungsten and coaxial electrodes in rat and man. Firstly, the sequelae of microneurography were examined for up to 1 month in a rat sciatic nerve model, using 3 techniques. Expression of the injury-associated protein GAP-43 was measured by immunofluorescence in sciatic nerve and dorsal root ganglia 3 and 28 days following sciatic nerve injury by microneurography electrodes. No increase in GAP-43 was observed in sciatic nerve 3 days following injury, but 28 days after injury the coaxial electrode was associated with an increase in GAP-43 expression. All electrodes were associated with an increase in GAP-43 in dorsal root ganglia 28 days after injury. The capacity of unmyelinated afferent fibres to induce neurogenic oedema was examined up to the 28th post-experimental day, as measured by Evan's Blue extravasation. The tungsten electrode induced a decrease in extravasation, which persisted for 28 days. In contrast, the decrease in plasma extravasation associated with lesions induced by the coaxial electrode returned to baseline within 7 days. The hind-limb withdrawal time from a noxious stimulus was also measured up to 28 days following injury. Both types of electrode induced a significant change in the immediate post-experimental period, but this returned to normal within 1 week. The direction of change differed between the tungsten and coaxial electrodes. In humans, symptomatology questionnaires were collected after microneurography experiments with the coaxial electrode. Thirty-two volunteers were studied. Two subjects reported mild paraesthesiae, which fully resolved within 24 h. This compares favourably with similar studies of the tungsten electrode.
authors.affiliation: Sherrington School of Physiology, St. Thomas' Hospital Medical School (UMDS), London SE1 7EH UK.
authors.forename: Andrew S C
authors.initials: ASC
authors.lastname: Rice
authors.forename: Nicholai Y
authors.initials: NY
authors.lastname: Andreev
authors.forename: Stephen B
authors.initials: SB
authors.lastname: McMahon
mesh_terms: D000818:Animals; D002452:Cell Count; D002857:Chromium; D005070:Evans Blue; D005260:Female; D005455:Fluorescent Antibody Technique; D019922:GAP-43 Protein; D005727:Ganglia, Spinal / Q000502:physiology; D006801:Humans; D008297:Male; D008562:Membrane Glycoproteins / Q000378:metabolism; D008839:Microelectrodes; D008856:Microscopy, Fluorescence; D009412:Nerve Fibers / Q000502:physiology; D009419:Nerve Tissue Proteins / Q000378:metabolism; D010147:Pain Measurement; D059348:Peripheral Nerve Injuries; D010525:Peripheral Nerves / Q000473:pathology; D051381:Rats; D017208:Rats, Wistar; D012584:Sciatic Nerve / Q000293:injuries / Q000473:pathology; D014414:Tungsten
chemical_list: D019922:GAP-43 Protein; D008562:Membrane Glycoproteins; D009419:Nerve Tissue Proteins; D002857:Chromium; D005070:Evans Blue; D014414:Tungsten