Prostanoid receptor-mediated calcium signaling in cultured rat astrocytes.

We investigated prostanoid-induced intracellular Ca2+ mobilization in Ca2+-sensitive dye fura-2-loaded cultured astrocytes. The thromboxane (TX) A2 analog STA2 (9,11-epithio-1 1,12-methano-TXA2) and/or prostaglandin (PG) F2α (each used at 1 μM) stimulated intracellular Ca2+ mobilization in single cultured rat type 1 astrocytes. Three response patterns were observed: only STA2-sensitive, only PGF2α-sensitive, and both prostanoids-sensitive cells. The Ca2+ response was prostanoid-dose-dependent (0.1–1 μM) and showed a rapid spike-like Ca2+ rise that peaked within 30 sec after the stimulation by the ligand. These observations suggest that type 1 astrocytes are heterogeneous with respect to the expression of receptors for TXA2 and PGF2α, which are linked to Ca2+ mobilization.