SYNERGISTIC ACTIVATION OF DNA-SYNTHESIS IN ASTROCYTES BY FIBROBLAST GROWTH-FACTORS AND EXTRACELLULAR ATP

The effects of extracellular ATP and polypeptide growth factors on DNA synthesis in primary cultures of rat astrocytes have been examined. I t was found that ATP acts synergistically with either acidic or basic fibroblast growth factor to stimulate DNA synthesis. The specificity o f this effect was demonstrated by the inability of ATP to potentiate D NA synthesis induced by platelet-derived growth factor or epidermal gr owth factor. ATP appears to act via P-2 purinergic receptors, because (a) it was more effective than adenosine and (b) the synergistic effec t was observed with the hydrolysis-resistant P-2 agonists, ADP beta S and ATP gamma S. The evidence suggests that extracellular ATP may be a n important factor in regulating the extent of gliosis and, as such, m ay be involved in mechanisms of neural injury and repair.