title: Spatial and temporal organization of pressure patterns throughout the unprepared colon during spontaneous defecation.
abstract: OBJECTIVE
  The aim of this study was to examine colonic motor events associated with spontaneous defecation in the entire unprepared human colon under physiological conditions.
  
  
  METHODS
  In 13 healthy volunteers a perfused, balloon-tipped, 17-lumen catheter (outer diameter, 3.5 mm; intersidehole spacing, 7.5 cm) was passed pernasally and positioned in the distal unprepared colon.
  
  
  RESULTS
  In the hour before spontaneous defecation, there was an increase in propagating sequence frequency (p = 0.04) and nonpropagating activity when compared to basal conditions (p < 0.0001). During this hour the spatial and temporal relationships among propagating sequences demonstrated a biphasic pattern. Both the early (proximal) and late (distal) colonic phases involved the whole colon and were characterized by respective antegrade and retrograde migration of site-of-origin of arrays of propagating sequences. There was a negative correlation between propagating sequence amplitude and the time interval from propagating sequence to stool expulsion (p = 0.008).
  
  
  CONCLUSIONS
  The colonic motor correlate of defecation is the colonic propagating sequence, the frequency and amplitude of which begin to increase as early as 1 h before stool expulsion. During the preexpulsive phase, the spatial and temporal relationship among the sites of origin of individual propagating sequences demonstrate a stereotypic anal followed by orad migration, which raises the possibility of control by long colocolonic pathways.
authors.affiliation: Department of Gastroenterology, The St. George Hospital, University of New South Wales, Kogarah, Australia.
authors.forename: P A
authors.initials: PA
authors.lastname: Bampton
authors.forename: P G
authors.initials: PG
authors.lastname: Dinning
authors.forename: M L
authors.initials: ML
authors.lastname: Kennedy
authors.forename: D Z
authors.initials: DZ
authors.lastname: Lubowski
authors.forename: D
authors.initials: D
authors.lastname: deCarle
authors.forename: I J
authors.initials: IJ
authors.lastname: Cook
mesh_terms: D000328:Adult; D003106:Colon / Q000502:physiology*; D003672:Defecation / Q000502:physiology*; D005260:Female; D005769:Gastrointestinal Motility / Q000502:physiology; D005772:Gastrointestinal Transit / Q000502:physiology; D006801:Humans; D008297:Male; D008365:Manometry; D012016:Reference Values