In a groundbreaking study, McGill University scientists have found a mechanism that could one day help cocaine addicts from relapsing.
The study, published in the scientific journal Neuron this week, found that the same brain cells that activate when we use cocaine—immune cells called "microglia" that protect the central nervous system (CNS)—can actually be re-stimulated with a third-party pharmaceutical to help kill cravings for the drug.
To accomplish the research, scientists at McGill injected mice with cocaine regularly. During this time, the microglia in the mices' brain began to work against damage that the cocaine was doing by producing tumor necrosis factor alpha (TNF-a)—an inflammatory molecule that researchers found is responsible for repressing the synapses related to drug addiction.
Over time, however, the mices' immune response faded, and so did their ability to resist addiction to the drug. Senior researcher on the study Dr. David Stellwagen told VICE this is indicative of how all drug addictions start.
"When something happens, you have a mixture of responses by the brain. Whether you're taking drugs, a disease, or anything else, you have a combination of the actual insult, and then the brain response that can actually be help or adaptive," he told VICE.
"All drugs of addiction are very powerful in the sense that they can reroute normal neural pathways—the brain can't prevent these changes, it can just try and limit them through immune responses. "
As the immune systems in the mice began to slow down, the researchers administered a pharmaceutical agent called MPLA (typically used in conjunction with vaccines) that kickstarted the microglia into action again. This triggered the mice to produce more TNF-a, which helped fight the ability of cocaine to further configure the mices' brain toward addiction.
As Stellwagen told VICE, however, the effect is only temporary—the process cannot fix cocaine damage or addiction, only prevent further damage for a small period of time. Stellwagen's hope is that the research can be used to help develop treatments to prevent relapse, or to help addicts fight back cravings in high-risk situations, such as being around the drug or triggering environments
"From a therapeutical angle, we can't solve the problem, but we might be able to give [somebody] a few days of relief from the cravings. That might get you through those hard periods where you might normally relapse."
Going forward, Stellwagen says that further tests need to be conducted on mice that have the choice to use cocaine or not, in order to determine how individual choice and temptation play against the brain's own immune response.
Follow Jake Kivanc on Twitter.