Subcellular localization of serotonin immunoreactivity in rat enterochromaffin cells

Histochemistry. 1985;82(4):351-5. doi: 10.1007/BF00494064.


Serotonin immunoreactive material was localized to rat enterochromaffin cells (EC cells) at the subcellular level using antibodies to serotonin (5-HT) raised in rabbits. Ultrathin sections from paraformaldehyde fixed plastic embedded tissues were directly labelled with the 5-HT antiserum, using the protein A-gold technique to visualize the immunoreaction. The 5-HT immunoreactivity (5-HT-IR) in the rat gastrointestinal mucosa was exclusively localized to epithelial EC cells with a low background over other epithelial non-enterochromaffin cells. Quantitative evaluation of the immunoreaction revealed that most of the 5-HT-IR in the cytoplasm of EC cells (60%) was located over the dense cores of the secretory granules. However, a significant part of the cytoplasmic 5-HT-IR (40%) was located outside the dense cores of the secretory granules which suggests that different forms of 5-HT storage may exist.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antigen-Antibody Reactions
  • Chromaffin Granules / analysis
  • Chromaffin System / analysis*
  • Digestive System / analysis
  • Digestive System / cytology
  • Enterochromaffin Cells / analysis*
  • Enterochromaffin Cells / ultrastructure
  • Epithelial Cells
  • Epithelium / analysis
  • Epithelium / ultrastructure
  • Gold
  • Male
  • Rabbits
  • Rats
  • Rats, Inbred Strains
  • Serotonin / analysis*
  • Staphylococcal Protein A
  • Subcellular Fractions / analysis


  • Staphylococcal Protein A
  • Serotonin
  • Gold