Fire–diffuse–fire model of dynamics of intracellular calcium waves

When Ca(2+) is released from internal stores in living cells, the resulting wave of increased concentration can travel without deformation (continuous propagation) or with burst-like behavior (saltatory propagation). We analyze the “fire–diffuse–fire” model in order to illuminate the differences between these two modes of propagation. We show that the Ca(2+) release wave in immature Xenopus oocytes and cardiac myocytes is saltatory, whereas the fertilization wave in the mature oocyte is continuous.