title: Stochastic fire-diffuse-fire model with realistic cluster dynamics.
abstract: Living organisms use waves that propagate through excitable media to transport information. Ca2+ waves are a paradigmatic example of this type of processes. A large hierarchy of Ca2+ signals that range from localized release events to global waves has been observed in Xenopus laevis oocytes. In these cells, Ca2+ release occurs trough inositol 1,4,5-trisphosphate receptors (IP3Rs) which are organized in clusters of channels located on the membrane of the endoplasmic reticulum. In this article we construct a stochastic model for a cluster of IP3R 's that replicates the experimental observations reported in [D. Fraiman, Biophys. J. 90, 3897 (2006)]. We then couple this phenomenological cluster model with a reaction-diffusion equation, so as to have a discrete stochastic model for calcium dynamics. The model we propose describes the transition regimes between isolated release and steadily propagating waves as the IP3 concentration is increased.
authors.affiliation: Departamento de Física, FCEN-UBA, Ciudad Universitaria, Pabellón I, 1428 Buenos Aires, Argentina.
authors.forename: Ana
authors.initials: A
authors.lastname: Calabrese
authors.forename: Daniel
authors.initials: D
authors.lastname: Fraiman
authors.forename: Daniel
authors.initials: D
authors.lastname: Zysman
authors.forename: Silvina
authors.initials: S
authors.lastname: Ponce Dawson
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D020013:Calcium Signaling; D004058:Diffusion; D053496:Inositol 1,4,5-Trisphosphate Receptors / Q000378:metabolism; D015640:Ion Channel Gating; D007700:Kinetics; D008954:Models, Biological; D013269:Stochastic Processes; D013997:Time Factors; D014982:Xenopus laevis / Q000378:metabolism
chemical_list: D053496:Inositol 1,4,5-Trisphosphate Receptors; D002118:Calcium