Histamine releasing action of calcium ionophore 985-I.

The polyether antibiotic 985-I induced histamine release from rat and mouse mast cells and human basophils. Histamine release induced by low concentrations (10-50 microM) of the ionophore was a selective (noncytotoxic) process. It was energy and Ca2+-dependent and was potentiated by glucose. In this respect the mode of action of 985-I was similar to that of the Ca2+-ionophore A23187. On the other hand some pharmacological agents (phencarol, verapamil and amitriptyline) inhibited histamine secretion induced by 985-I but not A23187-induced histamine release. These data point to some differences between the mechanisms of action of 985-I and A23187.