using Taqman assay.115 These two miRNAs are arrayed in tandem in the miR-212/132 cluster located on chromosome 17 in humans and chromosome 10 in rats.116 As such, both miRNAs are thought to function similarly. Next, to investigate the potential role for the miR-212/132 cluster in regulating cocaine intake we used a lentivirus to overexpress miR-212 in striatum of rats (Lenti-miR-212 rats) and assess the impact on self-administration behavior. We found that miR-212 overexpression did not impact cocaine intake in rats with restricted access.115 By contrast, striatal miR-212 overexpression strikingly reduced the motivation to consume cocaine in rats with extended access to the drug, reflected in progressively decreasing levels of cocaine intake across sessions.115 This progressively increasing inhibitory effect of miR212 on cocaine intake is opposite to the escalating rates of cocaine consumption typically observed in extended access rats. Conversely, disruption of miR-212 signaling in striatum, achieved through local infusion of an antisense oligonucleotide against miR-212, accelerated the emergence of escalated cocaine intake in extended access rats.115 These data suggest that miRNAs can regulate cocaine intake and potentially impact the development of compulsive consumption of the drug.
