Calcium waves.

Intracellular Ca2+ oscillations and waves are commonly observed both in excitable cells, including neurons, and in non-excitable cells. Current attempts to describe and explain these complex intracellular signals suggest that the oscillations are the result of a highly regulated mechanism, the details of which vary among different cells. Recently, the Xenopus oocyte has become an important model system in which a single pool of IP3 receptors release Ca2+ to initiate waves. The intrinsic bell-shaped dependence of the IP3 receptor on Ca2+ is sufficient to explain the regenerative wave phenomenon.