SEATTLE, Washington – Opioids continue to have a devastating effect on people across the United States who have become addicted to strong pain relievers. Even when patients use these prescriptions correctly, opioid use can still cause serious side effects. What if there was a “safer” opioid option? Scientists at the University of Washington say they may have discovered a way to create drugs that treat pain without causing addiction.
The study’s authors say the findings could one day produce opioids that bypass the brain’s pleasure center while retaining their pain-relieving properties.
“We have identified a major source of how mu opioids mediate reward,” says lead author of the study Daniel Castro, acting instructor in anesthesiology and pain medicine at UW Medicine and part of from the Bruchas Lab, which examines how neural circuits affect motivated behaviors, in an academic outing. “We have provided a plan of how the system works. “
“Mu-opioids, like morphine, act on specific receptors in the brain, like keys in a lock,” continues Michael Bruchas, professor of anesthesiology and pain medicine at UW. “We have isolated a new brain pathway where these receptors exert potent effects to promote reward consuming behavior.”
The new brain pathway for pain relief
The research team focused on the nucleus accumbens area of the brain, which scientists say is an integral part of the mind’s reward circuitry. Put simply, every time we do something fun, from eating to sex, dopamine neurons get activated in that region.
With regard to opioid pleasure in particular, they note that the opioid receptors are found in the dorsal raphe core area of the brain, which is close to the brainstem. When these receptors activate, they interfere with communications between the raphe and the nucleus accumbens.
“This discovery was quite unexpected,” adds Castro.
So, in light of these findings, the researchers believe they could create a safe opioid if there was a way to keep the new drug’s effects away from the dorsal raphe route to the nucleus accumbens.
The team focused on the opioid peptide receptor MOPR during this study. When something stimulates MOPR, it can interfere with or change the way people experience pain, reward behavior, breathing, and can even prompt drug addiction and overdose. It is important to note that MOPR is the most common opioid receptor that activates when a person takes prescription opioid medications.
When the way MOPR works suddenly changes, it can lead to great discomfort and withdrawal symptoms. Unfortunately, this can lead many patients to relapse into opioid abuse or, in some cases, to use other drugs such as heroin or morphine.
While much more work is needed before a safer opioid option enters the prescription drug market, this research is still a promising first step in the development of new, healthier pain medications.
The study is published in the journal Nature.