Effect of a potent selective protein kinase C inhibitor on histamine release from rat mast cells.

3,10-Dihydroxy-10-[(dimethylamino)methyl]-2,3,9,10,11,12-hexahydro-9- methyl-9,12-epoxy-1H-diindolo[1,2,3-fg-3',2',1'-k1]pyrrolo[3,4- l][1,6]benzodiazocin-1-one (UCN-01) strongly and dose-dependently inhibited histamine release from rat peritoneal mast cells that was induced by anti-immunoglobulin E (anti-IgE), calcimycin (A 23187), and 1,2-o-tetradecanoyl-13-acetate (TPA). The concentrations of UCN-01 required for 50% inhibition of histamine release induced by anti-IgE, A23187, and TPA were 1.5, 2.7, and 1.4 nM, respectively; these values are similar to those for 50% inhibition of protein kinase C. These results suggest possible participation cells induced by various secretagogues.