Excitable calcium wave propagation in the presence of localized stores

We study the propagation of calcium waves in the presence of a discrete dis tribution of calcium stores. Calcium-induced calcium release coupled to dif fusion can be used to produce a criterion for wave propagation across conne cted clusters of stores. The velocity of the resulting wave and its relatio nship to the frequency of the excitatory stimulus can then be described usi ng percolation theory. Simulations show a homogenous and a fractal regime a nd are in agreement with both experiments and theory.