title: Viscoelastic properties of the human colon.
abstract: Our objectives were to characterize colonic viscoelastic properties of the human descending colon by assessing pressure-volume (P-V) relationships during barostatic balloon distension. In 16 healthy subjects, a balloon was inflated to 44 mmHg and then deflated to 0 mmHg in 4-mmHg steps at 10, 30, and 60 ml/min, allowing volume fluctuations to stabilize at each pressure increment. Thereafter, these "quasi-static" P-V curves were compared with "dynamic" distensions to 300 ml, at 1 and 10 ml/s, before and after intravenous atropine in another five subjects. During quasi-static curves, balloon volume stabilized at each pressure increment. Quasi-static P-V curves were reproducible within individuals and approximated to a power exponential function and revealed hysteresis, indicative of viscoelasticity. Body mass index influenced quasi-static P-V curves during inflation but not during deflation. The colon was less compliant during dynamic distensions at 10 ml/s than during quasi-static distensions. Atropine increased quasi-static compliance and attenuated differences between quasi-static and rapid distensions. We conclude that colonic viscoelastic properties can be assessed by quasi-static P-V curves. Rapid colonic distension activated neural reflexes, thereby reducing colonic compliance compared with quasi-static distensions.
authors.affiliation: Gastroenterology Research Unit and Enteric Neurosciences Program, Mayo Clinic and Mayo Foundation, Rochester, Minnesota 55905, USA. bharucha.adil@mayo.edu
authors.forename: A E
authors.initials: AE
authors.lastname: Bharucha
authors.forename: R D
authors.initials: RD
authors.lastname: Hubmayr
authors.forename: I J
authors.initials: IJ
authors.lastname: Ferber
authors.forename: A R
authors.initials: AR
authors.lastname: Zinsmeister
mesh_terms: D000328:Adult; D001285:Atropine / Q000494:pharmacology; D015992:Body Mass Index; D003106:Colon / Q000187:drug effects / Q000502:physiology*; D003187:Compliance; D004548:Elasticity; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011312:Pressure; D015203:Reproducibility of Results
chemical_list: D001285:Atropine