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.
- Active stress
- Isometric contraction
- Acalculous biliary pain
- Apparent rate constant
Li, W., Luo, X., Tian, T., Hill, N., Ogden, R. W., Smythe, A., ... Bird, N. (2011). Cross-bridge apparent rate constants of human gallbladder smooth muscles. Journal of Muscle Research and Cell Motility, 32(3), 209-220. https://doi.org/10.1007/s10974-011-9260-y