Modulation of the maitotoxin response by intracellular and extracellular cations.

The aim of the present study was to characterize the role played by intracellular and extracellular calcium and sodium on the maitotoxin (MTX) response in Chinese hamster ovary (CHO) cells. The results presented here indicated that: (1) MTX activates calcium and sodium influx in a concentration-dependent manner; (2) extracellular calcium is required for the sodium influx; (3) removal of the extracellular sodium did not prevent the MTX-induced calcium influx; (4) elevation in the intracellular calcium concentration potentiates the MTX response; and (5) MTX, at the concentrations tested, did not compromise cell viability.