Sodium fluoride--a stimulus for a calcium-triggered secretory process.

Calcium triggers the secretion of histamine from mast cells after previous exposure of the cells to sodium fluoride. The secretory process can be divided into a fluoride-activating step and a calcium-induced secretory step dependent on cellular metabolic energy. The secretory response induced by compound 48/80 in the absence of extracellular calcium was found to decrease after fluoride pretreatment of the cells. The response was, however, unaffected, provided calcium was introduced to the cells simultaneously with compound 48/80.