The mechanism of histamine release induced by the ionophore X537A from isolated rat mast cells. II. The relationship between increase of cell volume and histamine release

The ionophore X537A induced swelling of isolated rat mast cells parallel to histamine release. Both actions were depressed by extracellular calcium and BSA, temperatures below 37°C, NEM, PMSF, and TTX, and were enhanced by high potassium and pretreatment of the cells with ATP. DSCG, theophylline, and DFP enhanced the histamine release noted after 10 min of incubation without influencing the swelling action of X537A. The swelling action could not be separated from histamine release and it is suggested that it right be inherent in the mechanism of secretion induced by X537A. The present results further distinguish histamine release induced by the two ionophores X537A and A23187.