UTP activates multiple second messenger systems in cultured rat astrocytes.

In astrocytes, a number of second messenger systems are activated upon stimulation with ATP. Recently, UTP has been demonstrated to have effects similar to ATP in some cell types. To determine if this was also true in astrocytes, cultured cells were stimulated with UTP which was found to evoke thromboxane release, stimulate inositol phospholipid turnover and increase intracellular free calcium concentration. A 53 kDa protein was identified on astrocyte membranes by immunoblotting with an antibody raised against a putative rat fibroblast P2U receptor. These data indicate that astrocytes possess a UTP-sensitive receptor which may be distinct from the P2Y-purinergic receptor.