Hippocampal CA1 Pyramidal Neurons of Mecp2 Mutant Mice Show a Dendritic Spine Phenotype Only in the Presymptomatic Stage
Figure 3
Quantitative electron microscopic analyses of CA3-CA1 excitatory synapses in the hippocampus of symptomatic mutant mice and age-matched wildtype littermates. (a) Electron micrographs of stratum radiatum in the CA1 area of the hippocampus from wildtype and symptomatic male mutant mice (P56). Representative excitatory synapses are indicated (asterisks). Scale bar: 400 nm. (b) Histograms show the number per unit of volume of asymmetric/excitatory CA3-CA1 synapses in CA1 stratum radiatum. The analysis using stereology (dissector method) revealed that MECP2 mutation does not affect excitatory synapse number. (c) Cumulative percentage of the cross-sectional area of dendritic spines associated with asymmetric CA3-CA1 synapses. Area of the dendritic spine was determined when associated with a presynaptic terminal. (d) Cumulative percentage of the cross-sectional area of presynaptic terminals associated with asymmetric CA3-CA1 synapses. Area of the presynaptic terminals was determined when associated with a dendritic spine.
