Chunk #14 — Results — Correlation structure analysis reveals that GluA1—PSD-95 protein expression in the lateral amygdala differentiates heroin abusers from control subjects
In consideration of the gene expression findings we wanted to explore glutamatergic measures at the protein level in the drug users. However, the greater variability of the protein measurements in the postmortem material as compared to the mRNA analysis, in combination with the small sample size, precluded a broad assessment of protein measures in the multi-drug abuse population of Study I. In order to obtain further insight into the potential dysregulation of glutamatergic function in the drug abusers, we thus focused on a large population of heroin abusers in Study II (Table 2) in which abundant amygdala tissue was available to allow detection of multiple proteins of interest. Given that the lateral nucleus is the major receptive subnucleus of the amygdala for glutamatergic input from the cerebral cortex and thalamus, western blot analysis was carried out in this subnucleus to measure protein levels of GluA1, PSD-95, Homer 1b/c as well mGluR5 and NMDA glutamate receptor subunit (GluN1) 1 (Fig. 2A). Furthermore, in order to address possible differences in the organization of the glutamatergic protein network, we used a structural equation
