Ca2+-induced excess capacitance fluctuation studied by phase-sensitive detection method in exocrine pancreatic acinar cells.

A phase-sensitive detection method in combination with whole-cell voltage-clamp was applied to exocrine pancreatic acinar cells from rat. The results have shown that cell-aialysis with a solution containing 5 X 10(-7) M Ca2+ induces stp-wise changes in cell capacitance. The size distribution of increasing and decreasing capacitance steps is compatible with the idea that these capacitance steps are the results of individual granular fusion and retrieval events. This method may enable experiments studying the exo- and endo-cytotic mechanisms in morphologically polarized secretory cells.