Schematic diagram showing signaling pathways in co-cultured-astrocytes. The data suggest that activation of astrocytes caused by co-culturing with mast cells through CD40-CD40 interaction mainly induces production of cytokines and chemokines via Rho-family GTPases/Ca2+-dependent PKC isoforms, MAP kinases, NF-κB and STAT1727. These cytokines subsequently re-activate astrocytes, and enhance the production of a variety of cytokines via Jak/STAT1701 or STAT1727/CBP pathways. TNFR1, TNF-α receptor 1; CD154, CD40 ligand. Broken lines show parts of the pathways requiring further study.