Elevated cyclic AMP levels fail to inhibit extracellular calcium dependent histamine secretion from rat mast cells

Rat mast cells preincubated with chelating agent and bathed in calcium-free medium fail to release histamine when stimulated by compound 48/80 and show elevated levels of cyclic AMP. When calcium is added to the bathing medium, these cells undergo a prompt secretory response yet cyclic AMP levels do not fall. It is suggested that the level of cyclic AMP may not regulate the change in membrane permeability believed produced by compound 48/80.