title: A mathematical model for the spontaneous contractions of the isolated uterine smooth muscle from patients receiving progestin treatment.
abstract: The in vitro spontaneous contractions of human myometrium samples can be described using a phenomenological model involving different cell states and adjustable parameters. In patients not receiving hormone treatment, the dynamic behavior could be described using a three-state model similar to the one we have already used to explain the oscillations of intrauterine pressure during parturition. However, the shape of the spontaneous contractions of myometrium from patients on progestin treatment was different, due to a two-step relaxation regime including a latched phase which cannot be simulated using the previous model without introducing an ad hoc mechanism to account for the extra energy involved in this sustained contraction. One way to do this is to introduce an anomalous rate of ATP consumption, the biochemical reasons for which have not yet been elucidated and which cannot be mathematically simulated using our experimental data. An alternative explanation is the reduced cycling rate of actin-myosin cross-bridges known to occur during the latch-phase. Our experimental findings suggest a third possibility, namely a sol-gel transition with a specific relaxation time constant, which would maintain a significant part of the cell population in the contracted-state until the intracellular-medium returns to its normal fluid behavior.
authors.affiliation: U.361 INSERM, Reproduction et Physiopathologie Obstétricale, Université René Descartes, Pavilion Baudelocque, 123 Bld de Port-Royal, 75014 Paris, France.
authors.forename: Christian
authors.initials: C
authors.lastname: Vauge
authors.forename: Thérèse-Marie
authors.initials: TM
authors.lastname: Mignot
authors.forename: Brigitte
authors.initials: B
authors.lastname: Paris
authors.forename: Michelle
authors.initials: M
authors.lastname: Breuiller-Fouché
authors.forename: Charles
authors.initials: C
authors.lastname: Chapron
authors.forename: Michel
authors.initials: M
authors.lastname: Attoui
authors.forename: Françoise
authors.initials: F
authors.lastname: Ferré
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000328:Adult; D003198:Computer Simulation; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D007743:Labor, Obstetric / Q000502:physiology; D008875:Middle Aged; D008954:Models, Biological; D009215:Myometrium / Q000187:drug effects* / Q000502:physiology; D011247:Pregnancy; D011372:Progestins / Q000494:pharmacology*; D014590:Uterine Contraction / Q000187:drug effects* / Q000502:physiology
chemical_list: D011372:Progestins; D000255:Adenosine Triphosphate