Extracellular guanosine and guanosine-5'-triphosphate increase: NGF synthesis and release from cultured mouse neopallial astrocytes.

Cultures of neonatal mouse cortical astrocytes synthesized NGF mRNA and released immunoreactive NGF (ir-NGF) into the culture medium. Addition of 10 microM guanosine or GTP to the cultures increased ir-NGF release by 6 and 2 fold, respectively, after 24 h, and increased NGF mRNA 6 fold after 4 h and 2-3 fold after 24 h. In contrast, neither adenosine nor ATP (each 1-100 microM) affected either NGF mRNA synthesis or ir-NGF release.