Principal component analysis suggests subtle changes in glutamate receptor subunit expression in the rat hippocampus following bilateral vestibular deafferentation

Previous studies have shown that lesions of the peripheral vestibular system result in electrophysiological dysfunction in the hippocampus. Given the importance of glutamate as a neurotransmitter in the hippocampus, it was predicted that bilateral vestibular deafferentation (BVD) would alter the expression of NMDA and AMPA receptors in this area of the brain. However, the results of studies conducted to date are inconsistent. In this study, we performed principal component analysis (PCA) on the expression of the NR1, NR2B, GluR1, GluR2 and GluR3 glutamate receptor subunits, as well as calmodulin kinase IIα (CaMKIIα) and phosphorylated CaMKIIα (pCaMKIIα), in the rat CA1, CA2/3 and dentate gyrus (DG) subregions of the hippocampus, at 6 months following BVD, using western blotting. The expressions of the different glutamate receptor subunits, in terms of NMDA versus AMPA receptor subunits, as well as CaMKIIα and pCaMKIIα, were tightly correlated, and this was shown again the loading plots. However, the pattern of the contributions of each protein to the first 2 principal components appeared to be inverted for the BVD group compared to the sham group.