Adult-generated Neurons in the Dentate Gyrus Send Axonal Projections to Field CA3 and Are Surrounded by Synaptic Vesicles

J Comp Neurol. 1999 Apr 19;406(4):449-60.

Abstract

The subgranule zone of the dentate gyrus in rats has been shown to be proliferative into adulthood and senescence. However, the connectivity of newly generated, identified neurons in the adult has not been definitively described. In the present study, 9 weeks after a series of intraperitoneal injections of 5-bromo-2'-deoxyuridine (BrdU), animals received stereotaxic iontophoretic injections of Fluoro-Gold (FG) into field CA3. Three weeks after FG injections, sections were analyzed for BrdU immunoreactivity (proliferative label), FG retrograde label, and either calbindin-D28k or synaptophysin immunohistochemistry. A large proportion (up to 44%) of BrdU-labeled cells in the dentate gyrus within regions of FG retrograde label incorporated FG. All of the doubly labeled (BrdU-FG) neurons also immunolabeled with the antibody to calbindin-D28k. Many doubly labeled (BrdU-FG) cells were also surrounded in three planes by synaptophysin immunoreactivity. We conclude that newly generated neurons in the dentate gyrus have the correct immunohistochemical profile, send appropriate axonal projections to field CA3, and are surrounded by profiles containing synaptic vesicle proteins.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Axons / chemistry*
  • Axons / ultrastructure
  • Bromodeoxyuridine
  • Calbindin 1
  • Calbindins
  • Dentate Gyrus / chemistry*
  • Dentate Gyrus / cytology
  • Fluorescent Dyes
  • Immunohistochemistry
  • Iontophoresis
  • Male
  • Nerve Tissue Proteins / analysis
  • Neural Pathways / chemistry
  • Neural Pathways / ultrastructure
  • Neurons / chemistry*
  • Neurons / ultrastructure
  • Rats
  • Rats, Sprague-Dawley
  • S100 Calcium Binding Protein G / analysis
  • Stilbamidines*
  • Synaptic Vesicles / chemistry*
  • Synaptic Vesicles / ultrastructure
  • Synaptophysin / analysis

Substances

  • 2-hydroxy-4,4'-diamidinostilbene, methanesulfonate salt
  • Calb1 protein, rat
  • Calbindin 1
  • Calbindins
  • Fluorescent Dyes
  • Nerve Tissue Proteins
  • S100 Calcium Binding Protein G
  • Stilbamidines
  • Synaptophysin
  • Bromodeoxyuridine