Serotonin-immunoreactive projections to the hippocampus from the interpeduncular nucleus in the rat

Neurosci Lett. 1986 Mar 14;64(3):259-62. doi: 10.1016/0304-3940(86)90338-1.


The possibility of a serotonergic projection from the interpeduncular nucleus (IPN) to the hippocampus was examined using a combined immunohistochemical-fluorescence retrograde tracing technique. About one third of the cells in the apical subnucleus of the IPN which projected to the hippocampus could be shown to contain serotonin immunoreactivity, whereas double-labeled cells were only rarely encountered in the lateral subnuclei. These findings suggest that the IPN sends both serotonergic and non-serotonergic projections to the hippocampus and that the serotonergic projections arise primarily from the apical subnucleus.

Publication types

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

MeSH terms

  • Amidines
  • Animals
  • Brain Mapping*
  • Fluorescent Antibody Technique
  • Hippocampus / analysis*
  • Hippocampus / anatomy & histology
  • Male
  • Mesencephalon / analysis*
  • Mesencephalon / anatomy & histology
  • Neural Pathways / analysis
  • Neural Pathways / anatomy & histology
  • Rats
  • Rats, Inbred Strains
  • Serotonin / analysis*
  • Serotonin / immunology
  • Staining and Labeling


  • Amidines
  • diamidino compound 253-50
  • Serotonin