title: Altered distribution of small-conductance calcium-activated potassium channel SK3 in Hirschsprung's disease.
abstract: OBJECTIVE
  SK3 channels are voltage-independent Ca(2+)-dependent K(+) channels that play a key role in regulating smooth muscle membrane potential during purinergic inhibitory neurotransmission in the colon. Dysmotility problems are common after a properly performed pull-through operation for Hirschsprung's disease (HSCR). We hypothesised that ganglionic bowel just proximal to the transition zone is abnormal and designed this study to investigate SK3 channel expression in HSCR.
  
  
  METHODS
  Entire resected bowel specimens were collected at the time of pull-through surgery for HSCR (n=6). Control colonic specimens were obtained at the time of colostomy closure in patients following anorectoplasty (n=6). SK3 protein expression was assessed qualitatively using immunofluorescence with confocal microscopy and quantitatively using western blot (WB) analysis.
  
  
  RESULTS
  Positive SK3 immunofluorescence was seen in the mucosa and in all three smooth muscle layers and the myenteric plexus in control specimens. SK3 immunofluorescence co-localised with PDGFRα. A band was detected at ~70kDa on WB. SK3 protein expression was barely detectable in aganglionic tissue and markedly reduced in the ganglionic bowel of 3 patients with HSCR compared to controls.
  
  
  CONCLUSIONS
  Decreased SK3 expression in ganglionic bowel may explain the basis of persistent bowel symptoms in some patients following a properly performed pull-through operation for HSCR.
authors.affiliation: National Children's Research Centre, Our Lady's Children's Hospital, Crumlin, Dublin, Ireland.
authors.forename: David
authors.initials: D
authors.lastname: Coyle
authors.affiliation: National Children's Research Centre, Our Lady's Children's Hospital, Crumlin, Dublin, Ireland.
authors.forename: Anne Marie
authors.initials: AM
authors.lastname: O'Donnell
authors.affiliation: National Children's Research Centre, Our Lady's Children's Hospital, Crumlin, Dublin, Ireland. Electronic address: prem.puri@ucd.ie.
authors.forename: Prem
authors.initials: P
authors.lastname: Puri
mesh_terms: D015415:Biomarkers / Q000378:metabolism; D015153:Blotting, Western; D016022:Case-Control Studies; D003106:Colon / Q000378:metabolism* / Q000601:surgery; D006627:Hirschsprung Disease / Q000378:metabolism* / Q000601:surgery; D006801:Humans; D007223:Infant; D007413:Intestinal Mucosa / Q000378:metabolism; D008297:Male; D009130:Muscle, Smooth / Q000378:metabolism; D009197:Myenteric Plexus / Q000378:metabolism; D051640:Small-Conductance Calcium-Activated Potassium Channels / Q000378:metabolism*
chemical_list: D015415:Biomarkers; C406328:KCNN3 protein, human; D051640:Small-Conductance Calcium-Activated Potassium Channels
keywords: Hirschsprung’s disease; Inhibitory junction potential; P2Y; PDGFRα; Purinergic; SK3