Effect of PKC inhibitors on the [Ca⁺⁺]_i response to anti-IgE antibody in basophils. Purified basophils (88% ± 4%) were labeled with fura-2 and analyzed by digital microscopy for changes in [Ca⁺⁺]_i in the presence or absence of the noted drugs. Panel A shows the results for 400 nmol/L bis-indolylmaleimide II and panel B the results for 100 nmol/L Go 6976 where the basophils were stimulated with 0.5 μg/mL anti-IgE antibody (n = 2 for each drug tested). Panel C shows the average results for three experiments in which basophils were incubated with or without 400 nmol/L BIS II for 10 minutes followed by a 5-minute treatment with or without 10 ng/mL PMA and then a stimulation with 0.5 μg/mL anti-IgE antibody. The conditions were (1) neither BIS nor PMA before challenge with anti-IgE antibody, (2) BIS II before incubation with anti-IgE antibody, (3) PMA before anti-IgE antibody, (4) BIS II (400 nmol/L) before PMA that preceeded anti-IgE antibody, and (5) same as 4 but with 1 μmol/L BIS II.