title: Differences in the regenerative response of neuronal cell populations and indications for plasticity in intraspinal neurons after spinal cord transection in adult zebrafish.
abstract: In zebrafish, the capacity to regenerate long axons varies among different populations of axotomized neurons after spinal cord transection. In specific brain nuclei, 84-92% of axotomized neurons upregulate expression of the growth-related genes GAP-43 and L1.1 and 32-51% of these neurons regrow their descending axons. In contrast, 16-31% of spinal neurons with axons ascending to the brainstem upregulate these genes and only 2-4% regrow their axons. Dorsal root ganglion (DRG) neurons were not observed to regrow their ascending axons or to increase expression of GAP-43 mRNA. Expression of L1.1 mRNA is high in unlesioned and axotomized DRG neurons. In the lesioned spinal cord, expression of growth-related molecules is increased in a substantial population of non-axotomized neurons, suggesting morphological plasticity in the spinal-intrinsic circuitry. We propose that locomotor recovery in spinal-transected adult zebrafish is influenced less by recovery of ascending pathways, but more by regrowth of descending tracts and rearrangement of intraspinal circuitry.
authors.affiliation: Zentrum für Molekulare Neurobiologie, Universität Hamburg, Martinistr. 52, D-20246 Hamburg, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Becker
authors.forename: Bettina C
authors.initials: BC
authors.lastname: Lieberoth
authors.forename: Catherina G
authors.initials: CG
authors.lastname: Becker
authors.forename: Melitta
authors.initials: M
authors.lastname: Schachner
mesh_terms: D000818:Animals; D015415:Biomarkers; D002455:Cell Division; D019922:GAP-43 Protein / Q000032:analysis / Q000235:genetics; D005727:Ganglia, Spinal / Q000502:physiology*; D017403:In Situ Hybridization; D009416:Nerve Regeneration / Q000502:physiology*; D009474:Neurons / Q000166:cytology / Q000502:physiology*; D012333:RNA, Messenger; D013116:Spinal Cord / Q000502:physiology*; D015027:Zebrafish
chemical_list: D015415:Biomarkers; D019922:GAP-43 Protein; D012333:RNA, Messenger