Trapping of secreted molecules at single-cell level using an HPLC resin particle under a videomicroscope

Particles of HPLC resins are used for the trapping of secreted molecules from a single cell. The basic molecules, e.g., histamine, are secreted from a single RBL-2H3 cell by granule exocytosis and are trapped by cation-exchange HPLC resins outside the cell. Since quinacrine is concentrated into the exocytotic and acidic microgranules in RBL-2H3 cells, which are used as a model cell line of mast cells, we measured the change in the fluorescence intensity of the quinacrine released from the cells and that of molecules trapped on the resin using a videomicroscope. By measuring the increase in the fluorescence intensity of the resins, we can estimate the real time course of molecular secretion from a single cell.