title: Passive elastic wall properties in isolated guinea pig small intestine.
abstract: The aim was to study and compare the passive biomechanical wall properties in the isolated duodenum and distal ileum of the guinea pig in vitro. The organ bath contained a Krebs-Ringer solution with 10(-2) M MgCl2 to abolish smooth muscle contractile activity. Stepwise inflation of an intraluminal balloon, in which the cross-sectional area (CSA) was measured, provided the distension stimulus. The circumferential wall tension-strain distributions and wall stiffness-strain relations were computed from steady-state values of these measurements in order to evaluate the passive elastic properties. The CSA always reached equilibrium within the 2-min distension period. The CSAs obtained in the distal ileum were higher than those in the duodenum (P < 0.001). The basal CSA was 17.31 +/- 1.14 mm2 and 12.96 +/- 0.42 mm2 for the distal ileum and the duodenum, respectively (P < 0.01). At a maximum pressure of 6 kPa, the CSA of the ileum was 56.63 +/- 1.81 mm2 and 36.86 +/- 1.76 mm2 for the duodenum (P < 0.01). The circumferential wall tension-strain distributions showed an exponential behavior that accorded well with the equation Y = exp(a+bX) with determination coefficients of 0.96 +/- 0.01 and 0.99 +/- 0.00 in the duodenal segments in the distal ileal segments, respectively. The values of a (intercept with the y-axis) were 0.54 +/- 0.11 and -0.35 +/- 0.19 for the duodenal and ileal segments, respectively (P < 0.001). The slope of the curves (b values) were 4.34 +/- 0.35 in the duodenal and 5.23 +/- 0.37 in the ileal segments (0.1 > P > 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Core Center of Gastrointestinal Motility and Biomechanics, Aarhus University Hospital, Denmark.
authors.forename: J H
authors.initials: JH
authors.lastname: Storkholm
authors.forename: G E
authors.initials: GE
authors.lastname: Villadsen
authors.forename: S L
authors.initials: SL
authors.lastname: Jensen
authors.forename: H
authors.initials: H
authors.lastname: Gregersen
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D002404:Catheterization; D004386:Duodenum / Q000502:physiology*; D004548:Elasticity; D017097:Electric Impedance; D005769:Gastrointestinal Motility / Q000502:physiology; D006168:Guinea Pigs; D007082:Ileum / Q000502:physiology*