title: A new method for visualization of gut mucosal cells, describing the enterochromaffin cell in the rat gastrointestinal tract.
abstract: OBJECTIVE
  Enterochromaffin (EC) cells in the gastrointestinal tract have an important function as regulators of secretion, motility and sensation. The EC cell has traditionally been described as bottle-shaped, with basally located stores of serotonin. Stimuli acting on the apical membrane trigger serotonin release, which in turn activates the subepithelial sensory nerve terminals. To better describe the appearance of EC cells, we developed a new method for visualization of mucosal cells.
  
  
  METHODS
  The stomach, small intestine and large intestine were excised from Sprague-Dawley rats and then fixed in formalin. The organs were everted and filled with pronase solution. Single cells and aggregates of formalin-fixed mucosal cells were collected by scraping the mucosa off the muscularis mucosa. EC cells were visualized by staining for immunoreactivity against serotonin.
  
  
  RESULTS
  EC cells with luminal extensions and very long (up to 80 microM) basally located axon-like extensions, sometimes connecting to neuron-like structures, were found. Other EC cells had no or only short and blunt basal extensions. Dividing serotonin-containing EC cells were also seen.
  
  
  CONCLUSIONS
  These findings could make an important contribution towards furthering our understanding of EC cell function in gastrointestinal physiology. This new method can also readily be used to give better visualization of the morphology of other mucosal cells.
authors.affiliation: Department of Gastroenterology, St Olav's Hospital HF, Trondheim University Hospital, Trondheim, Norway. bjorn.gustafsson@ntnu.no
authors.forename: Björn I
authors.initials: BI
authors.lastname: Gustafsson
authors.forename: Ingunn
authors.initials: I
authors.lastname: Bakke
authors.forename: Karin
authors.initials: K
authors.lastname: Tømmerås
authors.forename: Helge L
authors.initials: HL
authors.lastname: Waldum
mesh_terms: D000818:Animals; D002469:Cell Separation / Q000379:methods; D004759:Enterochromaffin Cells / Q000166:cytology*; D016267:External Fixators; D005260:Female; D005753:Gastric Mucosa / Q000166:cytology*; D006652:Histological Techniques; D007150:Immunohistochemistry; D007413:Intestinal Mucosa / Q000166:cytology*; D007420:Intestine, Large / Q000166:cytology; D007421:Intestine, Small / Q000166:cytology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012701:Serotonin / Q000032:analysis; D013194:Staining and Labeling; D016707:Tissue Fixation / Q000379:methods
chemical_list: D012701:Serotonin