direct relationship of Homer and dynamin-3 in neuropsychiatric populations, we next sought to assess whether the correlative data reflected true disturbance of the physical interactions between the proteins. We thus carried out immunoprecipitation of the lateral amygdala samples with Homer 1b/c followed by Western blot with dynamin-3 (Fig. 4C–D). As evident in figure 4E, there was a significant increase of dynamin-3 after Homer 1b/c immunoprecipitation in heroin abusers compared to controls (p=0.007). The apparent potentiation of dynamin-3- Homer physical interaction could just reflect the general enhancement of Homer 1b/c levels in the amygdala of heroin abusers. As such, we normalized the dynamin-3 immunoprecipitated protein levels in relation to the amount of Homer 1b/c measured by Western blot in the co-immunoprecipitated samples and noted a significant increase in heroin abusers as compared to controls (p=0.0287). Thus, there was an increase in the functional interaction between Homer 1b/c and dynamin-3 and, in addition, in the absolute amount of dynamin-3 linked to Homer 1b/c in heroin subjects. Although neither Homer 1b/c nor dynamin-3 levels alone were significantly associated with blood opiate concentrations, there was a significant positive correlation (r=0.492, p=0.019) between Homer 1 b/c—dynamin-3 interaction and blood morphine levels in heroin abusers.
