title: Cross-bridge apparent rate constants of human gallbladder smooth muscle.
abstract: This paper studies human gallbladder (GB) smooth muscle contractions. A two-state cross-bridge model was used to estimate the apparent attachment and detachment rate constants, as well as increased Ca2+ concentration from the peak active stress during the isometric contraction. The active stress was computed from a mechanical model based entirely on non-invasive routine ultrasound scans. In the two-state cross-bridge model, the two apparent rate constants, representing the total attached/detached cross-bridges, respectively, were estimated using active stress prediction for 51 subjects undergoing cholecystokinin-provocation test, together with estimates from the four-state cross-bridge model for a swine carotid, bovine tracheal and guinea pig GB smooth muscles. The study suggests that the apparent rate constants should be patient-specific, i.e. patients with a lower stress level are characterized by smaller apparent rate constants. In other words, the diseased GB may need to develop fast cycling cross-bridges to compensate in the emptying process. This is a first step towards more quantitative and non-invasive measures of GB pain, and may provide useful insight in understanding GB motility and developing effective drug treatments.
authors.affiliation: School of Mathematics and Statistics, University of Glasgow, Glasgow, G12 8QW, UK.
authors.forename: W G
authors.initials: WG
authors.lastname: Li
authors.forename: X Y
authors.initials: XY
authors.lastname: Luo
authors.forename: N A
authors.initials: NA
authors.lastname: Hill
authors.forename: R W
authors.initials: RW
authors.lastname: Ogden
authors.forename: T H
authors.initials: TH
authors.lastname: Tian
authors.forename: A
authors.initials: A
authors.lastname: Smythe
authors.forename: A W
authors.initials: AW
authors.lastname: Majeed
authors.forename: N
authors.initials: N
authors.lastname: Bird
mesh_terms: D002118:Calcium / Q000378:metabolism; D002766:Cholecystokinin / Q000378:metabolism; D005704:Gallbladder / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D008954:Models, Biological; D009119:Muscle Contraction; D009130:Muscle, Smooth / Q000378:metabolism*
chemical_list: D002766:Cholecystokinin; D002118:Calcium