Fig. 1. Endocytosis of single vesicles in INS-1 ß-cells. (A) A cell-attached recording where step-wise changes in capacitance (Im/2f) represent exocytosis (upward) and endocytosis (downward) of single vesicles. Transient changes in conductance (Re) during a capacitance step (arrows) result from the formation of fission pores. Step-wise changes in Re upon a capacitance step result from small phase offsets, which were corrected off-line prior to further analysis. (B) The size distribution, shown both as the square root of capacitance (fF^1/2) and vesicle diameter, of endocytotic events observed in cell-attached recordings with 2.6 mM Ca²⁺ in the patch-pipette and 0 mM glucose/0 mM Ca²⁺ in the bath.