Evaluation of the general protein levels between heroin and control subjects revealed that of the markers studied (Fig. 2), only Homer 1b/c protein expression differed significantly between the heroin and control groups, with a nearly 2-fold increase detected in heroin subjects (F1,34=11.132; p=0.002; Fig. 2B). No significant associations were observed between the heroin metabolites and protein levels of Homer 1 b/c or the other glutamatergic markers. Homer 1 b/c acts as a scaffold to maintain mGluRs, localized to the perisynaptic region, in the vicinity of the PSD (29, 30). A strong positive correlation was present between mGluR5 and Homer 1b/c levels in control subjects (r=0.831, p=0.004), but this relationship was absent in heroin abusers (r=0.013, p=0.949).
