Analysis of the expression of NMDAR subunits in GABAergic and glutamatergic synapses at postnatal day 6–7. A

<p>, Percentage of synapses positive for different NMDAR subunits out of all identified glutamatergic (white columns) and GABAergic synapses (black columns). <b>B</b>, Linear density of labeling (gold particle/µm) for different NMDAR subunits in glutamatergic synapses (white columns), GABAergic synapses (black columns) and extrasynaptic membranes (grey columns), measured on 100 nm thick electron microscopic sections. The extrasynaptic density of labeling was 0.09, 0.03 and 0.02 immunogold particles/µm for GluN1, GluN2B and GluN2A subunits, respectively. <b>C</b>, Size (µm²) of glutamatergic (white column) and GABAergic (black column) synapses. Data shown in A, B and C were measured from preembedding experiments. <b>D</b>, Density of labeling (gold particle/µm) for GluN1 subunits in glutamatergic synapses (white column), GABAergic synapses (black column) and extrasynaptic (E.S.) membranes (grey column, 0.03 gold particles/µm), measured from quantitative post-embedding experiments.