GAD2 and Alzheimer disease: However, we observed a significant reduction in the expression of GABA-related presynaptic proteins, GAD65 and VGAT, in both 3xTg-AD and 3xTg-AD-dnPAK groups when compared with NonTg mice, whereas specific markers of glutamatergic synapses (PSD95, GluN2B and Synaptophysin) and postsynaptic markers of GABAergic synapses (Gephyrin, GABAA receptor) remained unchanged (Fig. 4C).