[3H]serotonin release: an improved method to measure mast cell degranulation.

A method based on the release of tritium-labelled serotonin by activated mast cells in rodents is described. Mast cells incorporate labelled serotonin selectively and release the label after activation by non-specific stimulators (compound 48/80, polymyxin B sulphate, ATP, bovine chymotrypsin and L-alpha-lysophosphatidylcholine) or anaphylactic antibody and the corresponding antigen. These two types of activation were investigated in comparison with the toluidine blue microscopic rat mast cell degranulation test, and a methodological study of the release of [3H]serotonin is described. The measurement of labelled serotonin release provides a simple and quick assay of mast cell degranulation compared to the time required for the classical rat mast cell degranulation technique and achieves a greater sensitivity.