(B-G) Munc18-1 null hippocampal neurons were rescued with wildtype Munc18-1a or a Munc18-1 mutant, Y473A, in which Y473 was replaced with alanine.(C) Quantification of confocal images. Average synaptic Munc18-1 intensity (M18WT: 389 ± 85 a.u., n=21; M18Y473A: 321 ± 48 a.u., n=20, t-test with Welch correction, p = 0.4868), somatic Munc18-1 intensity (M18WT: 328 ± 49 a.u., n=21; M18Y473A: 245 ± 42 a.u., n=20, t-test, p = 0.2810), synapse number (M18WT: 129 ± 14, n=21; M18Y473A: 159 ± 16, n=20, t-test, p = 0.1548) and dendrite length (M18WT: 0.433 ± 0.028, n=21; M18Y473A: 0.461 ± 0.037, n=20, t-test, p = 0.5473). 