Effects of extracellular calcium concentration on neurite outgrowth in PC12 cells by staurosporine. 
Staurosporine as an inhibitor of protein kinases can induce neuronal differentiation in PC12 cells.  We investigated the role of extracellular Ca(2+) on staurosporine inducing neurite outgrowth in PC12 cells.  The cells were cultured during cell differentiation in the presence of 214 nM staurosporine with 0.0-0.7 Ca(2+)mM as treatment media.  We obtained the fraction of neurite-bearing cells, total neurite length and the percentage of cytotoxiciy.  The results showed that decrease or increase of extracellular calcium ions resulted in correspondingly significant decrease or increase in total neurite length and cell differentiation in treated cells.  With an increase of extracellular calcium concentration from 0.0 to 0.7 mM, the percentage of cytotoxicity of the PC12 cells decreased (p<0.05).  Our data suggest that staurosporine uses the extracellular calcium ions to affect on neurite outgrowth.