Figure 9. The distribution of time constants for endocytotic events is Ca²⁺ dependent.

A, distributions of first (a) and second (b) time constants from double exponential decays, and single time constants from mono-exponential decays (c). Data include excess and compensatory responses, and all stimulations throughout the experiment. Note axis break between 15 and 30 s, so that the wide range of values could be displayed on the same plot. B, for a fixed pulse duration (320 ms) the majority of excess retrieval events were fitted with a double exponential function (59/69; 85 %). Only a fraction of responses with compensatory retrieval required two exponentials for a good fit (11/40; 27.5 %). C, Ca²⁺ dependence of single exponential time constants. Single τ values were binned by amount of Ca²⁺ entry and plotted as means ±s.e.m. (•) and medians (⋆) for each bin. The x-axis error bars represent the means ±s.e.m. for the range of Ca²⁺ entry covered by a particular bin.