title: Ultrastructural localization of sympathetic axons in experimental rat sciatic nerve neuromas.
abstract: The ultrastructural localization of sympathetic axons was investigated in normal rat sciatic nerves and experimental sciatic nerve neuromas. The best ultrastructural localization of noradrenaline in the dense-cored vesicles of sympathetic axons was accomplished following pretreatment of rats with nialamide and 5-hydroxy dopamine, followed by fixation according to the modified chromaffin technique of Tranzer and Richards (1976). After such preparation, sympathetic axons containing 5-hydroxy dopamine-labelled dense-cored vesicles could be identified in normal sciatic nerve. Large accumulations of labelled dense-cored vesicles were also found in acute neuromas, up to 1 week after nerve section. Much smaller numbers of dense-cored vesicles could be identified in chronic neuromas from 2 to 3 weeks following nerve section. Sympathetic axons could also be identified following electron probe X-ray microanalysis of the tissue sections, using chromium detection as the marker for the noradrenaline-containing dense-cored vesicles. Unusual configurations of Schwann cell subunits, which enclosed myelinated fibres and sympathetic axon sprouts within the same basal lamina, were identified in the acute neuromas, 3-7 days after nerve section. Such configurations may be of relevance to the pathophysiological interaction which develops between sympathetic efferent and sensory fibres in peripheral nerve neuromas.
authors.affiliation: Department of Clinical Neurology, Institute of Neurology, Queen Square, London, UK.
authors.forename: J R
authors.initials: JR
authors.lastname: Small
authors.forename: J W
authors.initials: JW
authors.lastname: Scadding
authors.forename: D N
authors.initials: DN
authors.lastname: Landon
mesh_terms: D000320:Adrenergic Fibers / Q000737:chemistry / Q000187:drug effects / Q000648:ultrastructure*; D000818:Animals; D001369:Axons / Q000737:chemistry / Q000187:drug effects / Q000648:ultrastructure*; D019439:Chromaffin Cells / Q000737:chemistry / Q000648:ultrastructure; D004577:Electron Probe Microanalysis; D005260:Female; D006892:Hydroxydopamines / Q000032:analysis; D008854:Microscopy, Electron; D008996:Monoamine Oxidase Inhibitors / Q000494:pharmacology; D009410:Nerve Degeneration / Q000187:drug effects / Q000502:physiology; D009413:Nerve Fibers, Myelinated / Q000737:chemistry / Q000648:ultrastructure; D009463:Neuroma / Q000473:pathology* / Q000648:ultrastructure; D009476:Neurons, Efferent / Q000737:chemistry / Q000187:drug effects / Q000648:ultrastructure; D009526:Nialamide / Q000494:pharmacology; D009638:Norepinephrine / Q000032:analysis; D051381:Rats; D017208:Rats, Wistar; D012584:Sciatic Nerve / Q000737:chemistry / Q000473:pathology*; D016707:Tissue Fixation
chemical_list: D006892:Hydroxydopamines; D008996:Monoamine Oxidase Inhibitors; C027802:5-hydroxydopamine; D009526:Nialamide; D009638:Norepinephrine