Astrocytes are considered a reticulate network of cells, through which
calcium signals can spread easily. In Bergmann glia, astrocytic cells of the
cerebellum, we identified subcellular compartments termed 'glial microdomains'.
These elements have a complex surface consisting of thin membrane sheets,
contain few mitochondria and wrap around synapses. To test for neuronal interaction
with these structures, we electrically stimulated parallel fibers. This stimulation
increased intracellular calcium concentration ([Ca2+]
i) in small compartments within Bergmann glial cell processes similar
in size to glial microdomains. Thus, a Bergmann glial cell may consist of
hundreds of independent compartments capable of autonomous interactions with
the particular group of synapses that they ensheath.
