An international team led by Australian and US universities has studied a new treatment for cocaine addiction that could also have implications for all types of drug addictions.
Australians rank fourth in the world when it comes to cocaine abuse.
The popular recreational drug makes users feel energetic, confident and talkative. It’s also highly addictive.
Lead author Dr Alexis Northcutt from the University of Colorado Boulder and the University of Adelaide’s Professor Mark Hutchinson had initially been researching neuropathic and chronic pain.
They discovered the immune receptor known as toll-like receptor 4 (TLR4) amplified the addictive properties of morphine.
Their team wanted to see if the same was true for cocaine.
“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,” Professor Hutchinson said.
They discovered the immune system constantly talks to the brain, keeping it updated on any health changes.
It was once thought cells in the brain called glial cells merely acted as somewhat of a glue holding the brain together and feeding neurons, but it turns out these cells can recognise and respond to things.
“So what’s happening is glial cells in the brain are seeing cocaine or seeing morphine as, well, opioids and they think ‘oh no, this is an invading pathogen’, it’s like stranger danger,” Dr Northcutt said.
“Then they mount this immune response that seems to be a really critical element to what makes drugs addictive.”
Knowing this, the trick was to find a way to stop opioids from binding to TLR4.
The team used the drug plus naloxone, which has proved a success. It hopes to start clinical trials soon.
“So cocaine, for example, can’t bind toll-like receptor 4, so it can’t activate glial cells,” Dr Northcutt said.
“If we don’t get information, then we don’t get the activation of the reward areas of the brain that normally you would see with cocaine.”
Treatment could help beat addiction to other drugs: researchers
What most excited the researchers was that the treatment could also be used to curb the addictive properties of other drugs.
“It means we could potentially see a single intervention for a wide range of addictions in the future,” Professor Hutchinson said.
Dr Northcutt said the research team also had some promising results with alcohol and methamphetamines.
“We haven’t looked into things like tobacco or other drugs yet but there’s a strong possibility that this is a very common occurrence across many substances that are abused,” she said.
Dr Northcutt added though that addictions were complicated and would always also require psychological as well as medical intervention.
But she said if a drug could at least take the edge off cravings and withdrawals it would offer addicts who were motivated to recover, a greater chance of success.
The research was published in the Nature journal, Molecular Psychiatry.