Calcium dependent modulation of histamine release from mast cells by sodium and potassium

The inhibition of sodium-potassium ATPase by ouabain or potassium-deprivation led to a potentiation of histamine release induced by antigen or compound 48/80 from rat mast cells. The fullest potentiation required 30 min preincubation of cells with ouabain or without potassium before adding the triggering agent. The potentiation was observed provided that the calcium concentration was less than 0.5 mM. The effect of sodium-potassium ATPase blockade was reversed slowly by washing out ouabain or by adding potassium. Metabolic inhibition with deoxyglucose and dinitrophenol-blocked histamine release observed under all conditions described. Histamine release from rat mast cells was also elicited when the cells were incubated in sodium-deficient media where sodium was replaced by sucrose. Potassium-deprivation potentiated this secretion process previously shown to be dependent upon metabolic energy and sensitive to millimolar calcium concentrations.