ATP is released from astrocytes and is involved in the propagation of calcium waves among
them. Neuronal ATP secretion is quantal and calcium-dependent, but it has been suggested
that ATP release from astrocytes may not be vesicular. Here we report that, besides the
described basal ATP release facilitated by exposure to calcium-free medium, astrocytes
release purine under conditions of elevated calcium. The evoked release was not affected
by the gap-junction blockers anandamide and flufenamic acid, thus excluding purine efflux …