Research suggests that certain microRNAs may play a role in regulating the rewarding effects of various substances. MicroRNA-132/212 is reported to negatively modulate opioid reward by targeting the dopamine transporter in the ventral tegmental area. Other microRNAs, such as miR-124 and a newly identified microRNA, may have similar regulatory effects on the rewarding properties of other substances, including methamphetamine and cocaine.