Changes in histamine secretion from mast cells caused by digitalis glycosides.

Cardiotonic glycosides modify histamine secretion from rat mast cells in the following way. (1) Preincubation (30 min) of mast cells with liposoluble glycosides (10(-4) mol/l) increases the spontaneous histamine secretion by about 5%. (2) Preincubation of mast cells with 10(-4) mol/l liposoluble glycosides (digitoxin, digoxin, digitoxigenine) decreases histamine release induced by compound 48/80 in the presence of calcium, whereas the water soluble glycoside, strophanthin G, has no effect on the secretion. (3) Preincubation of mast cells in a calcium-free medium with the glycosides (10(-4) mol/l) has a dual-effect on histamine secretion induced by compound 48/80: water soluble glycosides (strophanthin G and K) potentiate histamine release, whereas the liposoluble glycosides (digitoxin, digitoxigenine) decrease the secretory response. The difference in the activity of different glycosides could be explained by their dual effects, namely an inhibition of Na+K(+)-ATPase which leads to an increase in histamine release, and intracellular action(s) of liposoluble glycosides leading to a decrease of histamine secretion.