SEATTLE, Wash. — Opioids continue to have a devastating affect on people across the United States who have become addicted to the powerful painkillers. Even when patients use these prescriptions properly, opioid use can still lead to severe side-effects. So what if there was a “safer” opioid option? Scientists from the University of Washington say they may have discovered a way to create drugs which treat pain without leading to addiction.
Study authors explain that these discoveries may one day produce opioids that bypass the pleasure center of the brain while retaining their pain-relieving properties.
“We identified a major source of how mu-opioids mediate reward,” says lead study author Daniel Castro, acting instructor in anesthesiology and pain medicine at UW Medicine and part of The Bruchas Lab, which examines how neural circuits affect motivated behaviors, in a university release. “We provided a blueprint of how the system works.”
“Mu-Opioids, like morphine act on specific receptors in the brain, like keys in a lock,” continues Michael Bruchas, UW professor of anesthesiology and pain medicine. “We isolated a new brain pathway where these receptors exert powerful effects to promote reward consumption behavior.”
The new brain path to relieving pain
The research team focused on the nucleus accumbens brain area, which scientists believe is an integral region in the reward circuit of the mind. In simpler terms, whenever we do anything pleasurable, from eating to sex, dopamine neurons activate within this region.
Regarding opioid pleasure specifically, they note that opioid receptors sit in the dorsal raphe nucleus brain area, which is close to the brain stem. When these receptors activate, they interfere with communications between the raphe and nucleus accumbens.
“This finding was pretty unexpected,” Castro adds.
So, in light of these findings, researchers believe they can create a safe opioid if there were a way to draw the new drug’s effects away from the dorsal raphe to nucleus accumbens pathway.
The team focused on the opioid peptide receptor MOPR during this study. When something stimulates the MOPR, it can interfere with or alter how people feel pain, reward behavior, respiration, and can even incite substance abuse and overdose. Importantly, MOPR is the most common opioid receptor which activates when someone takes opioid prescription drugs.
When MOPR’s functioning changes abruptly, it can result in great discomfort and withdrawal symptoms. This can unfortunately lead to many patients falling back into opioid abuse or, in some cases, using other drugs like heroin or morphine.
While much more work is necessary before a safer opioid option enters the prescription drug market, this research is still a promising first step in terms of developing new, healthier pain-fighting drugs.
The study is published in the journal Nature.