Table 3.

Density of EAAT2 in terminals compared to glia in synaptosomal preparations

	Mix	Anti-73 kDa
Terminals (synaptosomes)
Total number of terminals assessed	70	41
Length of labeled membrane	19.7	7.47
Number of gold particles in membrane	21	8
Mean density	0.99	1.5
Number of gold particles in cytosol	14	3
Glia
Total number of profiles assessed	8	7
Length of labeled membrane	5.7	6.6
Number of gold particles in membrane	50	33
Mean density	6.3	5.0
Ratio of density (terminals/glia)	0.16	0.3

Sections of synaptosomes were labeled either with the anti-73 kDa antibody (AB#171) or with a mixture (“Mix”) of the following antibodies: 0.2 μg/ml anti-B12 (AB#150), 0.2 μg/mlanti-B493 (AB#95) and 0.5 μg/ml anti-B518 (AB#94). The length of membrane and number of particles in a number of selected labeled terminal and glial profiles are given along with the density of labeling calculated from these values. Glial labeling density over the membrane was found to be significantly greater than terminal membrane labeling density (P<0.001). Data tested are derived from 10 randomly selected electron micrographs from one experiment. Qualitatively similar results were obtained with other preparations. The number of glial profiles was small because of their partial exclusion from the synaptosomal preparation. Relative labeling densities were also calculated and were comparable to those obtained in slices. However, there were some differences between antibodies suggesting that relative labeling efficiency of antigen by the antibody affects the weak terminal vs. strong glial labeling differentially.