Addition of the protein synthesis inhibitor cycloheximide (CX, 1-mu-g/ml) and the RNA synthesis inhibitor actinomycin D (AD, 0.1-mu-g/ml) to unfractionated mouse peritoneal mast cells simultaneously with IgE anti-DNP, for 24 h prior to challenge, completely blocked antigen-induced 5-HT release. Responses to anti-IgE were strongly abrogated whereas responses to the calcium ionophore A23187 were not affected. When CX and AD were added to presensitized cells their effects on antigen and anti-IgE-induced release were much reduced. These results suggest a requirement for protein synthesis during mast cell sensitization.
