File:Myo-Inositol Enlarges Excitatory Synaptic Sites in the Cortex.jpg

English: "Cortical synapse size increases when myo-inositol is supplemented during development. (A) For analysis of the visual cortex area V1, the diet of mouse pups was supplemented from birth with myo-inositol until postnatal day 35. (B, Top), single optical confocal sections of synaptic Homer immunostaining in binocular primary visual cortex area V1b, layer II/III in control (B, Left), and myo-inositol-supplemented mice (B, Right) at postnatal day 35. Mice received 50 mg myo-inositol/kg body weight/day from birth. (B, Bottom), puncta masks after image processing. (C and D) Quantification in layer II/III of V1 from images as in B of synaptic Homer puncta density (C) and size (D) of control and myo-inositol-supplemented animals. Animal averages are shown, and means were compared (Student’s t test, two-tailed unpaired; control, N = 5 mice, data averaged from 3/2/2/2/2 sections per mouse; myo-inositol, N = 4, data averaged from 2/2/2/2 sections per mouse). (E and F) Quantification in layer V of V1b of synaptic Homer puncta density (E) and size (F) of mice treated as in A and imaged as in B (Student’s t test, two-tailed unpaired; control, N = 5 mice; myo-inositol, N = 4)." "Mice received dietary supplementation with 50 mg myo-inositol/kg body weight/day once a day orally, from birth until P35 to probe effects while the V1 is maturing (Fig. 3A). This amount was chosen based on the dietary uptake in infants (SI Appendix, Extended Methods). Body weight was unaffected (SI Appendix, Fig. S7). We first analyzed synaptic markers in layer II/III, which is rich in corticocortical connections. Validating that Homer immunostaining marks excitatory postsynaptic sites, we determined that 89 ± 2 % of Homer puncta colocalized with PSD-95 (SI Appendix, Fig. S8). No effect of dietary myo-inositol supplementation was found on the density of the analyzed excitatory and inhibitory synaptic markers (Fig. 3 B and C and SI Appendix, Fig. S9 and Supplemental Results). We extended our analysis to the size of synaptic specializations, a correlate of synaptic strength in the neocortex (22). Importantly, the size of Homer puncta in V1 was strongly increased in myo-inositol-supplemented mice by 49 ± 18%, from 0.129 ± 0.02 µm2 in control animals to 0.192 ± 0.02 µm2 in myo-inositol-supplemented mice (Fig. 3D) (Student’s t test; n = 5/4, t = 2.764, P = 0.028). Cumulative distribution frequency analysis of Homer puncta supported that they were enlarged by myo-inositol across their full size range (SI Appendix, Fig. S9). The size of other synaptic markers was unaffected (SI Appendix, Fig. S9)."