Synaptic transmission in autaptic excitatory munc18-1 neurons expressing M18WT or a non-phosphorylatable Munc18-1 variant, M18Y473F, was tested with whole-cell patch clamp electrophysiology.(F) The amount of DSE-triggered EPSC depression was quantified by the ratio of the average EPSC amplitude (taken over 4 pulses given at 0.2 Hz) before or immediately following 10 seconds depolarization to 0mV. Typical EPSCs before and following DSE induction are depicted on the left. Average DSE (M18WT: 0.57 ± 0.04 fold, n=20; M18Y473F: 0.53 ± 0.04 fold, n=16, t-test, p = 0.5227). 