Table 1.

Quantification of immunogold localization of AMPA receptors in the CA1 stratum radiatum

Antibody Animal CA1-stratum radiatum gold per synapse Number of synapses
GluR2 gold per synapse WT (2 animals; 2 experiments using 1 antibody) 0.13 480
KO (2 animals; 2 experiments using 1 antibody) 0.005 372
GluR2/3 gold per synapse WT (2 animals; 4 experiments using 1 antibody) 1.23 860
KO (2 animals; 4 experiments using 1 antibody) 0.18 856
GluR3 1/100 gold per synapse WT 2 animals 0.25 460
KO 2 animals 0.18 385
GluR3 1/25 gold per synapse WT 2 animals 0.55 379
KO 2 animals 0.41 339
GluR1 gold per synapse WT (3 animals; 7 experiments using 2 antibodies) 0.55 1346
KO (3 animals; 7 experiments using 2 antibodies) 0.31 1324
GluR1 gold per micrometer WT (3 animals; 3 experiments using 2 antibodies) 3.5 641
KO (3 animals; 3 experiments using 2 antibodies) 2.2 664
Control WT (1 animal; 1 experiment using 1 antibody) 0 117
KO (1 animal; 1 experiment using 1 antibody) 0 109
  • All differences between WT (GluR2+/+) and KO (GluR2−/−) are highly significant, except for GluR3, for which the decreases in KOs are slightly significant (p<0.05 for 1/100; p<0.02 for 1/25). Average synapse length for GluR1-labeled sections is 0.20 μm (n=641) and 0.19 μm (n=664) for WT and KO, respectively. This 5% decrease in length is significant. For the latter study, the same area of neuropil was examined (>2000 μm2) for WT and KO, although the area contributed by large structures, especially dendrites, was not subtracted. This indicates that there are, at most, only small changes in synapse number and length.