Aim: To examine if toosendanin (TSN) affects intracellular free-Ca(2+) concentration ([Ca(2+)](i)) in neuroblastoma pluglioma hybrid cells (NG108-15 cells).
Methods: The [Ca(2+)](i) was determined by laser-scanning confocal microscopic imaging technique in which Fluo-3 was used as Ca(2+) indicator.
Results: TSN induced an increase in resting [Ca(2+)](i) and in high K(+)-evoked Ca(2+) transient in differentiated NG108-15 cells. The TSN-induced increase in [Ca(2+)](i) was dose-dependent and disappeared in CdCl(2-), nifedipine-containing or Ca(2+)-free solution, and appeared after washing out the Ca(2+) channel blockers or adding Ca(2+).
Conclusion: TSN increased [Ca(2+)](i) in differentiated NG108-15 cells. The [Ca(2+)](i) enhancement was due to the influx of extracellular Ca(2+) and related to L-type Ca(2+) channels.