Insight into the neurobiology of addiction can be gained from studies of post-mortem human brain. We found monocyte chemoattractant protein 1 (MCP-1, CCL2), a key innate immune chemokine, increased several fold in multiple regions of post-mortem alcoholic brain compared to age matched moderate drinking controls (Fig. 3) (He and Crews 2008). MCP-1 protein levels from alcoholic and control human brains indicated increased MCP-1 in ventral tegmental area (VTA), substantia nigra (SN), hippocampus and amygdala of alcoholic brains. We also found increased levels of microglial markers across alcoholic brain (He and Crews 2008). Chronic alcohol treatment of mice causes a similar persistent increase in brain MCP-1 (Fig. 3) (Qin et al. 2008). Interestingly, ethanol treatment of rat hippocampal brain slice cultures also increase MCP-1 and other innate immune genes (Fig. 3) (Zou and Crews 2010). These studies indicate that ethanol induces MCP-1 in rats and mice creating neurobiological changes found in human addicted brain (Fig. 3). Similarly, human methamphetamine addicts and mice treated with methamphetamine show persistent increases in innate immune proteins (Loftis et al. 2010). Increased protein levels are also
