Capillary electrophoretic study of individual exocytotic events in single mast cells.

In this work we have demonstrated the application of on-column dynamic release of serotonin from individual granules within rat peritoneal mast cells (RPMCs). These granules are approximately 0.25 fl in volume and represent some of the smallest entities studied by capillary electrophoresis (CE). With the coupling of high-speed CE and laser-induced native fluorescence, a time resolution of 0.002 min and a detection limit of 0.9 amol (S/N = 3, rms) were achieved. By using a secretagogue as the running buffer for CE, we resolved the peak profile of individual degranulation events released due to exocytosis. The average amount of serotonin released for five RPMCs analyzed was 33 amol +/- 16%.