Spiral waves and intracellular calcium signalling

Confocal imaging of intracellular Ca²⁺ brings a new level of resolution to the study of hormonal control of intracellular Ca²⁺ release. This approach has demonstrated the existence of pulsatile circular and spiral waves of Ca⁺ release induced by receptor activation. The data obtained by confocal imaging support a new framework for understanding intracellular Ca²⁺ signalling. The goal of this chapter is to review our data on the complexity of intracellular Ca²⁺ release in Xenopus oocytes, introduce the concept of Ca²⁺ excitability as a model for Ca²⁺ release and discuss the implications for encoding intracellular signal information.