Studies have implicated microRNAs in both human [10–13] and animal models of addiction [7, 9, 14–19]. For example, Lewohl et al. [10] have shown that numerous microRNAs are upregulated in post-mortem frontal cortex of human alcoholics and similarly, microRNA expression is modified in cortices of ethanol-dependent mice [15]. MicroRNAs may be responsible for the ethanol-induced response of addiction-associated signaling molecules such as the D1 dopamine receptor, Drd1 [20] and brain-derived neurotrophic factor, Bdnf [17, 21]. Importantly, several studies have demonstrated perturbations of miRNA-mRNA networks as a result of ethanol exposure [7, 9, 11] but to our knowledge, none has directly evaluated the temporal nature of such networks.
