CHRNA7 and type 2 diabetes mellitus: The levels of nAChR α7 and α4 subunit proteins in the hippocampus (CA3, which is well-known as one of the areas as most critical to cognitive function) were significantly lower in the T2DM than control samples (α7 subunit: 100.0±5.1% in NDM, 79.2±2.9% in T2DM, F=1.522, p<0.01; α4 subunit: 100.0±4.7% in NDM, 74.8±4.7% in T2DM, F=0.008, p<0.01), but no significant differences in these levels in the frontal and temporal cortices were observed (Figure 1A, 1B).