Fig. 2

Glycine induced spine head enlargement is protein synthesis and mTORC1 dependent. (a) Time-course of relative changes in spine head diameter (represented as percentage of baseline value) for neurons treated with glycine (400 μM) either alone (red, n = 1538 spines across 20 cells) or after pretreatment with anisomycin (blue, n = 494 spines across 8 cells) or rapamycn (green, n = 684 spines across 9 cells). Control cells were treated with HBS alone. (b) Cumulative probability distribution and mean (+/−SEM) change in spine head width for cells treated with glycine with or without anisomycin, or rapamycin assessed 45 min post-stimulation. *p < 0.05 relative to control cells treated with HBS alone. (c) Example images taken from neurons treated with 400 μM glycine and either 40 μM anisomycin (blue) or 200 nM rapamycin (green). Scale bar = 1 μm. (d) Box plots showing distribution of values for spine head width across each group at baseline (recorded at min 0). One way ANOVA and post Hoc measures reveal significant variation of two groups from control values. (e) Frequency histogram of all spines in groups down in d, (n = 5061), colored according to groups determined by kmeans clustering. (f) Box plot showing range of spine head values represented in each of the three groups determined by k means cluster (Group 1 “small”, n = 3068; Group 2 “medium”, n = 1504; Group 3 “large”, n = 438 spines). (g-i) Kernel density estimates of spine head width for each cluster group as identified in 2E–F at baseline (minute 0) and 45 min post stimulus onset (middle panel). Right, direct comparison of mean values for spine head width at min0 vs min45