Figure 5. Increased free [Ca²⁺]_i led to axial immobilization of vesicles.

(A) Relative axial movement over time of the exemplary LDCV chosen from the cell kept at a free [Ca²⁺]_i of ≈80 nM in Figure 2A (grey circle) and (B) the resulting CD vs. time. Time is color coded (red-yellow-green-blue) (C) Relative axial movement over time of the exemplary LDCV chosen from the cell kept at a free [Ca²⁺]_i of ≈650 nM in Figure 2E (grey circle) and (D) the resulting CD vs. time. Time is color coded (red-yellow-green-blue). (E) Relative axial CDs for each individual LDCV observed in the exemplary cell kept at a free [Ca²⁺]_i of ≈80 nM in Figure 2A and (F) the exemplary cell kept at a free [Ca²⁺]_i of ≈650 nM in Figure 2E. The results for each single LDCV were plotted against the recording time (2 min, X-axis segments). The exemplary LDCV of each cell (B, D) is represented within the dotted grey boxes. (G) Axial CD size distribution of the two cells shown in (E) and (F) (bin size 10 nm). The overall median value of both cells is 42 nm (gray dotted line). Note the increased contribution of axial CDs smaller than the median as the [Ca²⁺]_i was increased from 80 to 650 nM. However, this increase was not as pronounced as that of lateral mobility shown in Figure 2I.