In biological systems we often consider the presence or absence of a chemical
signal as the switch controlling whether a cellular process is on or off.
However, many intracellular signalling molecules, such as calcium, can perform
multiple functions. Within cells there exist different calcium channels which
release calcium into the cell but are triggered by different mechanisms, and
serve significantly different purposes. Thus there must be some more
sophisticated aspect of the calcium dynamics that produces these targeted
signals. We have developed a computational model, parameterised using
experimental data, to explore the modulatory effect of activating IP3R calcium
channels on the regular calcium oscillations within heart cells. Through varying
the parameters within and beyond known experimental bounds, we can identify the
key features of the composite signal that can be produced using known
intracellular machinery and decode the underlying message.