Figure 5.

Size of the readily releasable pool of synaptic vesicles is unchanged in synaptotagmin polylysine motif mutants. (A) Sample traces showing that application of a hypertonic sucrose solution (bar) to synaptic regions for 10 s increases the frequency of miniature synaptic potentials. (B) Frequency of miniature synaptic potentials is plotted versus time from 10 s before to 10 s after the application of sucrose. (C) Because the basal rate of spontaneous release is greater in the mutants, the frequency of release was normalized to the basal rate within each genotype for comparison. The sucrose-induced, increased frequency in polylysine motif mutants (gray triangles, n = 9 fibers) is comparable to that in transgenic controls (black circles, n = 9 fibers). Error bars are SEM.