Time course of fiber outgrowth from fetal anterior hypothalamic heterografts

Research output: Contribution to journalArticle

15 Scopus citations

Abstract

Fetal anterior hypothalamic (AH) heterografts can restore circadian rhythmicity to animals rendered arhythmic following ablation of the suprachiasmatic nucleus (SCN). Behavioral restoration of circadian activity typically begins between two and six weeks post-implantation. The time course of fiber outgrowth from fetal AH heterografts was examined to determine whether neuronal outgrowth from the implants precedes the typically observed effects of such implants upon circadian behavior. Fetal mouse or rat AH tissue containing the SCN was implanted into the third ventricle of SCN-lesioned hamsters. Using species-specific monoclonal antibodies generated against mouse or rat neuronal elements, fiber outgrowth into the host hypothalamus was examined at 2, 4, 7, 14, 30 and 45 days after implantation. Fibers were observed to have emerged from the implant at the earliest time point examined. Four days after surgery, individual fibers had extended up to 0.6 mm into the host neuropil. By 14 days post-implantation, outgrowth from the implant had formed a dense fiber plexus in the host hypothalamus. This observation demonstrates that neuronal integration of the implant with the host brain begins within 48 hours of implantation, and is extensively established well before a restoration of rhythmicity is typically observed. Thus, on the basis of the time course of fiber outgrowth, it is clear that neuronal contact between graft and host may mediate the observed restoration of circadian rhythmicity.

Original languageEnglish (US)
Pages (from-to)212-219
Number of pages8
JournalBrain Research
Volume614
Issue number1-2
DOIs
StatePublished - Jun 18 1993
Externally publishedYes

Keywords

  • Fetal hypothalamic graft
  • Fiber outgrowth
  • Heterograft
  • Neural transplantation
  • Suprachiasmatic nucleus

ASJC Scopus subject areas

  • Neuroscience(all)
  • Molecular Biology
  • Clinical Neurology
  • Developmental Biology

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