title: Reactive astrocytic responses to denervation in the motor cortex of adult rats are sensitive to manipulations of behavioral experience.
abstract: Recent research has suggested that mild denervation of the neocortex of adult rats may facilitate neuronal growth in response to behavioral changes. Astrocytes react to denervation, produce growth-promoting factors and are a potential mediator of this denervation-facilitated growth. The present study assessed whether astrocytic reactions to denervation vary dependent upon post-injury behavioral experience. Denervation of the transcallosal afferents to the motor cortex was induced via partial transections of the corpus callosum. Transected- or sham-operated rats were then either forced to use the opposite forelimb (via limb-restricting vests) or permitted to use both forelimbs normally for 8 days. In the motor cortex, the surface density of glial fibrillary acidic protein (GFAP)-immunoreactive (IR) astrocytic processes and the density of basic fibroblast growth factor (FGF-2)-IR glial cells was significantly increased as a result of transections alone and as a result of forced forelimb-use alone in comparison to controls. The combination of transections and forced-use significantly enhanced GFAP-IR in comparison to all other groups, but did not further enhance FGF-2-IR. These findings are consistent with behavior and denervation having interactive influences on astrocytic reactivity in the motor cortex. These results also raise the possibility that astrocyte-mediated support of neural restructuring after brain injury might be enhanced with appropriate post-injury behavioral manipulations.
authors.affiliation: Psychology Department, University of Washington, Guthrie Hall Box 351525, Seattle 98195, USA.
authors.forename: S D
authors.initials: SD
authors.lastname: Bury
authors.forename: A C
authors.initials: AC
authors.lastname: Eichhorn
authors.forename: C M
authors.initials: CM
authors.lastname: Kotzer
authors.forename: T A
authors.initials: TA
authors.lastname: Jones
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D001522:Behavior, Animal / Q000502:physiology*; D002452:Cell Count; D003337:Corpus Callosum / Q000473:pathology / Q000502:physiology / Q000601:surgery; D003714:Denervation; D016222:Fibroblast Growth Factor 2 / Q000378:metabolism; D005552:Forelimb / Q000502:physiology; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D005911:Gliosis / Q000473:pathology; D007103:Immobilization / Q000502:physiology; D007150:Immunohistochemistry; D008297:Male; D009044:Motor Cortex / Q000166:cytology / Q000473:pathology / Q000502:physiology*; D011187:Posture / Q000502:physiology; D051381:Rats; D020318:Rats, Long-Evans; D012149:Restraint, Physical / Q000295:instrumentation; D013003:Somatosensory Cortex / Q000473:pathology / Q000502:physiology
chemical_list: D005904:Glial Fibrillary Acidic Protein; D016222:Fibroblast Growth Factor 2