FIGURE 1.

Excitatory and/or inhibitory signals trigger Ca²⁺ elevations in astrocytes and lead to gliotransmitter release. Scheme depicting input signals that trigger astrocyte Ca²⁺ elevations and respective transmitter release. Both excitatory (+) and inhibitory (–) signals cause global or focal Ca²⁺ elevations in astrocytes (Left), and precede gliotransmitter release that might exert excitation or inhibition of neighboring synapses (Right). For each reference, the region studied is indicated in black (Amy, Amygdala; BrSt, brainstem; CA1, CA1 subfield of the hippocampus; Ctx, cortex; DG, dentate gyrus; hHip, human hippocampus; Str, Striatum). ^∗Indicates the studies that described functional consequences to focal Ca²⁺, rather than global Ca²⁺ responses.