Subcellular localization of serotonin immunoreactivity in rat enterochromaffin cells.
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.
D000818:Animals; D000937:Antigen-Antibody Reactions; D002837:Chromaffin Granules / Q000032:analysis; D002838:Chromaffin System / Q000032:analysis*; D004064:Digestive System / Q000032:analysis / Q000166:cytology; D004759:Enterochromaffin Cells / Q000032:analysis* / Q000648:ultrastructure; D004847:Epithelial Cells; D004848:Epithelium / Q000032:analysis / Q000648:ultrastructure; D006046:Gold; D008297:Male; D011817:Rabbits; D051381:Rats; D011919:Rats, Inbred Strains; D012701:Serotonin / Q000032:analysis*; D013205:Staphylococcal Protein A; D013347:Subcellular Fractions / Q000032:analysis
D013205:Staphylococcal Protein A; D012701:Serotonin; D006046:Gold