S100β stimulates calcium fluxes in glial and neuronal cells

The glial-derived protein S 100β can act as a mitogen or a neurotrophic factor, stimulating proliferation of glial cells or differentiation of immature neurons. We report here that dimeric S100β evokes increases in intracellular free calcium concentrations ([Ca²⁺]_i) in both glial cells and neuronal cells. The [Ca²⁺]_i increase exhibited a rapid transient component which was not affected by removal of extracellular calcium and a sustained component which appeared to require influx of extracellular calcium through Ni²⁺-sensitive channels. S100β also stimulated hydrolysis of phosphoinositides, suggesting a mobilization of calcium from intracellular stores. These data suggest that although the final biological responses of neuronal and glial cells to S100β are différent, transduction of the S100β signal in both cell types involves changes in [Ca²⁺]_i.