Chunk #15 — Results — Correlation structure analysis reveals that GluA1—PSD-95 protein expression in the lateral amygdala differentiates heroin abusers from control subjects
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 multi-group analysis model to determine whether the correlation structure relationship of the glutamatergic markers differed between heroin abusers and controls. The structural equation model was based on published data regarding the known biological organization/connectivity of the glutamatergic markers in the PSD. As such, the model evaluated correlations between, e.g., GluA1—PSD-95, PSD-95—Homer 1, mGluR5—Homer 1 and GluN1—PSD-95 (4, 13, 16, 17, 27, 28). Specifically, the structural equation multi-group analysis model tested whether equal or different correlation structures between heroin abusers and controls best described the data set. The analysis revealed that heroin abusers and control subjects differ in the correlation pattern of the glutamatergic markers evaluated within the lateral amygdala (AIC values, unconstrained model: 52.96, structural residual model: 58.11, X2, p=0.006). Further analysis revealed that alterations in the correlation structure were due to a difference in the relationship between GluA1 and PSD-95 (zeta = 2.31). Independent Pearsons correlation also showed that GluA1—PSD-95 correlated positively in heroin abusers (r=0.534 p=0.003), but not
