title: Cholinergic modulation of epithelial integrity in the proximal colon of pigs.
abstract: BACKGROUND
  Within the gut, acetylcholine (ACh) is synthesised by enteric neurons, as well as by 'non-neuronal' epithelial cells. In studies of non-intestinal epithelia, ACh was involved in the generation of an intact epithelial barrier. In the present study, primary cultured porcine colonocytes were used to determine whether treatment with exogenous ACh or expression of endogenous epithelium-derived ACh may modulate epithelial tightness in the gastrointestinal tract.
  
  
  METHODS
  Piglet colonocytes were cultured on filter membranes for 8 days. The tightness of the growing epithelial cell layer was evaluated by measuring transepithelial electrical resistance (TEER). To determine whether ACh modulates the tightness of the cell layer, cells were treated with cholinergic, muscarinic and/or nicotinic agonists and antagonists. Choline acetyltransferase (ChAT), cholinergic receptors and ACh were determined by immunohistochemistry, RT-PCR and HPLC, respectively.
  
  
  RESULTS
  Application of the cholinergic agonist carbachol (10 µm) and the muscarinic agonist oxotremorine (10 µM) resulted in significantly higher TEER values compared to controls. The effect was completely inhibited by the muscarinic antagonist atropine. Application of atropine alone (without any agonist) led to significantly lower TEER values compared to controls. Synthesis of ACh by epithelial cells was proven by detection of muscarinic and nicotinic receptor mRNAs, immunohistochemical detection of ChAT and detection of ACh by HPLC.
  
  
  CONCLUSIONS
  ACh is strongly involved in the regulation of epithelial tightness in the proximal colon of pigs via muscarinic pathways. Non-neuronal ACh seems to be of particular importance for epithelial cells forming a tight barrier.
authors: Institute of Veterinary Physiology, Faculty of Veterinary Medicine, Leipzig University, Leipzig, Germany.
authors: Szilvia
authors: S
authors: Lesko
authors: Ignaz
authors: I
authors: Wessler
authors: Gotthold
authors: G
authors: Gäbel
authors: Carola
authors: C
authors: Petto
authors: Helga
authors: H
authors: Pfannkuche
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D002795:Choline O-Acetyltransferase / Q000378:metabolism; D018678:Cholinergic Agents / Q000494:pharmacology*; D003106:Colon / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D004246:Dimethylphenylpiperazinium Iodide / Q000494:pharmacology; D017097:Electric Impedance; D020895:Enterocytes / Q000166:cytology / Q000187:drug effects / Q000201:enzymology; D005260:Female; D007150:Immunohistochemistry; D007413:Intestinal Mucosa / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D018722:Nicotinic Agonists / Q000494:pharmacology; D062793:Occludin / Q000235:genetics / Q000378:metabolism; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011950:Receptors, Cholinergic / Q000235:genetics / Q000378:metabolism; D011976:Receptors, Muscarinic / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D034421:Sus scrofa; D062826:Zonula Occludens-1 Protein / Q000235:genetics / Q000378:metabolism
chemical_list: D018678:Cholinergic Agents; D018722:Nicotinic Agonists; D062793:Occludin; D012333:RNA, Messenger; D011950:Receptors, Cholinergic; D011976:Receptors, Muscarinic; D062826:Zonula Occludens-1 Protein; D004246:Dimethylphenylpiperazinium Iodide; D002795:Choline O-Acetyltransferase