"... Here we present a formalism by which mathematical models for Ca2+-regulated Ca2+ release sites are derived from stochastic models of single-channel gating that include Ca2+ activation, Ca2+ inactivation, or both. Such models are stochastic automata networks (SANs) that involve a large number of functional transitions, that is, the transition probabilities of the infinitesimal generator matrix of one of the automata (i.e., an individual channel) may depend on the local [Ca2+] and thus the state of the other channels. Simulation and analysis of the SAN descriptors representing homogeneous clusters of intracellular Ca2+ channels show that (1) release site density can modify both the steady-state open probability and stochastic excitability of Ca2+ release sites, (2) Ca2+ inactivation is not a requirement for Ca2+ puffs or sparks, and (3) a single-channel model with a bell-shaped open probability curve does not lead to release site activity that is a biphasic function of release site density. ..."
Model Type: Channel/Receptor
Currents: I Calcium
Simulation Environment: CalC Calcium Calculator (web link to model)
Implementer(s): Matveev, Victor V. [m a t v e e v at n j i t . e d u ]
Nguyen V, Mathias R, Smith GD. (2005). A stochastic automata network descriptor for Markov chain models of instantaneously coupled intracellular Ca2+ channels. Bulletin of mathematical biology. 67 [PubMed]