Na+/Ca2+ exchanger inhibitors inhibit neurite outgrowth in PC12 cells.

To elucidate the role of Na+/Ca2+ exchanger (NCX) in neurite outgrowth, we investigated the effects of NCX inhibitors on neurite outgrowth in PC12 cells. KB-R7943 and 3′,4′-dichlorobenzamil, NCX inhibitors, inhibited the neurite outgrowth caused by nerve growth factor (NGF). NCX inhibitors inhibited the neurite outgrowth caused by dibutylyl cAMP, which rapidly reorganizes the cytoskeleton. KB-R7943 inhibited the neurite outgrowth caused by Y-27632, an inhibitor of Rho kinase (ROCK) that regulates actin. However, NCX inhibitors did not inhibit NGF-induced phosphorylation of extracellular signal-regulated kinase. These results suggest that NCX inhibitor affects downstream of the Rho–ROCK signal transduction pathways in neurite outgrowth.