An international team of scientists has discovered a key mechanism that causes opioid addiction — and there’s a drug that can selectively block that addiction response, without damaging the brain or interfering with pain relief.
According to a study by the University of Adelaide and the University of Colorado, published in the Journal of Neuroscience, the drug (+)-naloxone may be able to help drug addicts and patients with severe pain alike. It works by shutting down a specific immune system receptor, the Toll-Like receptor 4 (TLR4). Ordinarily, these receptors bind to opiates (like morphine) and then amplify the body’s addictive response to these drugs.
In a press release, the lead author of the study, Dr. Mark Hutchinson from the University of Adelaide, describes their findings:
“Our studies have shown conclusively that we can block addiction via the immune system of the brain, without targeting the brain’s wiring. Both the central nervous system and the immune system play important roles in creating addiction, but our studies have shown we only need to block the immune response in the brain to prevent cravings for opioid drugs. [...]
The drug (+)-naloxone automatically shuts down the addiction. It shuts down the need to take opioids, it cuts out behaviours associated with addiction, and the neurochemistry in the brain changes – dopamine, which is the chemical important for providing that sense of ‘reward’ from the drug, is no longer produced.”
While the drug naloxone has been used to treat emergency overdoses for years, this is the first clear evidence that (+)-naloxone (a variant of naloxone) might be able to prevent and aid opiate addiction in pain patients and drug addicts. Clinical trials of (+)-naloxone co-formulated with morphine, intended for patients with severe pain, may even begin within the next 18 months.