and Cohen, 2008). miRNAs also appear to mediate the cellular adaptations induced by exposure to a number of drugs of abuse, including nicotine (Huang and Li, 2008), cocaine (Chandrasekar and Dreyer, 2009), opioids (He et al., 2010), and alcohol (Sathyan et al., 2007; Pietrzykowski et al., 2008; Miranda et al., 2010; Lewohl et al., 2011). In subsequent sections, we discuss major biological processes now known to respond to fluctuations in levels of specific miRNAs, several of which were upregulated in the brain of human alcoholics. We also uncover general patterns of miRNA regulation that may be common to a variety of addiction disorders.
