Mechanism of histamine release from rat mast cells induced by the ionophore A23187: effects of calcium and temperature.

1 The mechanism of histamine release from a pure population of rat mast cells induced by the lipid soluble antibiotic, A23187, has been studied and compared with data for anaphylactic histamine release reported in the literature. 2 Histamine release induced by A23187 in the presence of calcium 10(-3) mol/l was completed in 10 minutes. By preincubation of the mast cells with A23187 for 10 min in the absence of calcium the histamine release induced by calcium, 10(-3) mol/l or 5 x 10(-3) mol/l, was completed in 90 s and 45 s, respectively. 3 A23187-induced histamine release was maximal with calcium 10(-3) mol/l when the cells were incubated at 33 to 39 degrees C for 10 minutes. 4 The cellular mechanism, which was stimulated by A23187 and calcium for the release of histamine, was irreversibly inactivated by incubation at 45 degrees C. 5 An inhibition of energy metabolism was excluded as the cause of the heat inactivation. 6 The dependence of A23187-induced histamine release on calcium and temperature, the time course of histamine release and the heat inactivation are consistent with the view that the same mechanism is involved in A23187-induced and anaphylactic histamine release.