Astrocyte calcium microdomains are inhibited by bafilomycin A1 and cannot be replicated by low-level Schaffer collateral stimulation in situ.

Astrocyte Gq GPCR and IP3 receptor-dependent Ca(2+) elevations occur spontaneously in situ and in vivo. These events vary considerably in size, often remaining confined to small territories of astrocyte processes called "microdomains" and sometimes propagating over longer distances that can include the soma. It has remained unclear whether these events are driven by constitutive (basal) GPCR signaling activity, neuronal action potential-dependent or quantal vesicular release, or some combination of these mechanisms.