  Most of the functions performed by astrocytes in brain information processing
are related to calcium waves. Experimental studies involving calcium waves
present discrepant results, leading to gaps in the full understanding of the
functions of these cells. The use of mathematical models help to understand the
experimental results, identifying chemical mechanisms involved in calcium waves
and the limits of experimental methods. The model is diffusion-based and uses
receptors and channels as boundary conditions. The computer program developed
was prepared to allow the study of complex geometries, with several astrocytes,
each of them with several branches. The code structure allows easy adaptation
to various experimental situations in which the model can be compared. The code
was deposited in the ModelDB repository, and will be under number 266795 after
publication. A sensitivity analysis showed the relative significance of the
parameters and identifies the ideal range of values for each one. We showed
that several sets of values can lead to the same calcium signaling dynamics.
This encourages the questioning of parameters to model calcium signaling in
astrocytes that are commonly used in the literature, and it suggests better
experimental planning. In the final part of the work, the effects produced by
the endoplasmic reticulum when located close to the extremities of the branches
were evaluated. We conclude that when they are located close to the region of
the glutamatergic stimulus, they favor local calcium dynamics. By contrast,
when they are located at points away from the stimulated region, they
accelerate the global spread of signaling.
