Potential New Treatment for Drug Addictions

A new treatment for drug addictions could be on the horizon if researchers from the University of Adelaide and University of Colorado are on the right track.
The international research project points to new treatments for cocaine addiction but could have implications for all types of drug addictions.
Published in the Nature journal Molecular Psychiatry, the researchers have  focused  on the role of the immune receptor known as Toll-Like receptor 4 (TLR4) and discovered a  mechanism in the body's immune system that amplifies addiction to cocaine. It also shows that cocaine’s rewarding properties can be blocked, thanks to a drug that prevents the immune system's response.
"Our previous studies have shown that TLR4 is responsible for amplifying addiction to opioid drugs such as heroin, but this is the first time we've discovered it has a key role to play in cocaine addiction," says Professor Mark Hutchinson, ARC Research Fellow in the University of Adelaide's School of Medical Sciences.
Lead author Alexis Northcutt, from the Center for Neuroscience at the University of Colorado Boulder, says: "We've demonstrated conclusively that cocaine interacts with TLR4 to produce a pro-inflammatory effect in the brain. The effect is necessary to convey the drug's rewarding effects. Without it, reward is greatly reduced.
"Combined with our previous work, this suggests that the immune signalling may be a key mechanism underlying the rewarding and reinforcing effects of drugs such as opioids, cocaine, and potentially other abused substances, like methamphetamine and alcohol," she says.
In laboratory studies, the researchers had previously demonstrated that opioid addiction could be blocked, by using the drug (+)-naloxone (pronounced: PLUS nal-OX-own) to prevent opioids from binding to TLR4.
"The cocaine study has had the same result, which is unique in itself. We now have two major drugs of addiction that are both being amplified by TLR4, which we can stop through the use of (+)-naloxone," says Professor Hutchinson, who is also Director of the ARC Centre of Excellence for Nanoscale BioPhotonics at the University.
"These are very exciting and encouraging results. It means that we could potentially see a single intervention for a wide range of addictions in the future."
This research is supported by the National Institute on Drug Abuse, the National Institute on Alcohol Abuse and Alcoholism and the Department of Defense in the United States, and the Australian Research Council