Although a lot of behavioral studies are out there on drug addiction, no one really knows how addiction develops at the molecular level. A new review by researchers in Miami describes lots of evidence from more than 80 studies suggesting that non-coding RNAs, such as microRNAs (miRNAs) and long non-coding RNAs (lncRNAs), might have a big role to play in this process.
The review gathers evidence from many studies that link non-coding RNAs to addiction. Here are a few key points from the paper:
- Addiction is essentially neuroplasticity gone wrong, with the brain creating “bad” connections that make a person crave a drug. miRNAs appear to have a hand in regulating neuroplasticity and learning. The authors describe studies that suggest miRNAs are involved in changing neuronal connections. The role of lncRNAs in learning and plasticity is less clear, however.
- Many studies show that miRNAs are involved in responses to cocaine, amphetamine, nicotine, alcohol, and opioids. In other studies, the levels of some lncRNAs are altered in response to heroin and cocaine.
- Both lncRNAs and miRNAs interact with epigenetic factors that could regulate addiction.
The authors say that many questions still remain about how non-coding RNAs might regulate addiction or cause addiction to take hold in the brain.
Read all the evidence at Frontiers in Genetics, June 2012.