New Direction for Painkiller Research: Target Opioid Receptors Outside of the Brain to Reduce Side Effects

New Direction for Painkiller Research: Target Opioid Receptors Outside of the Brain to Reduce Side Effects

By Staff

There may be a new direction in the development of opioid medication after researchers discover a different target for opioid receptors in the brain.  Most opioid pain medications target what is called the mu opioid receptor in the brain, which result in side effects and the potential for abuse.  Researchers found that targeting delta opioid receptors on sensory neurons in peripheral tissues can avoid the side effects and abuse potential with current opioid pain medications.

“People living with chronic pain have few innovative analgesic options available to them outside of systemic opioids,” says senior study author Nathaniel Jeske of the University of Texas Health Science Center at San Antonio. “Being able to increase the responsiveness of peripheral opioid receptor systems could lead to a reduction in systemic opioid administration, thereby reducing the incidence of side effects.”

The study in rats, which was published August 25 in Cell Reports, set out to address the problem of mu opioid receptors by targeting delta opioid receptors in the peripheral nervous system rather than the brain and spinal cord, which could produce fewer side effects in animals.

Jeske and lead author Allison Doyle Brackley, also of the University of Texas Health Science Center at San Antonio found that a protein called GRK2 binds to and prevents delta opioid receptors on rat sensory neurons from responding normally to opioids.  When these peripheral neurons were exposed to a natural inflammatory molecule called bradykinin, GRK2 moved away from the delta opioid receptors, setting off a biochemical reaction that restored the functioning of these receptors.

So, the rats with the reduced GRK2 levels regained their sensitivity to the pain-relieving effects of the drug that activates the delta opioid receptors – and did so without the need for an inflammatory trigger.

“By shedding light on how inflammation activates delta opioid receptors, this research could potentially lead to the development of safer, more effective opioids for the treatment of pain,” Jeske said.

The researchers’ next steps are to attempt to replicate the findings in rats, using human tissue.

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Authored by: Staff

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The claim that this new drug will not have any addictive side effects is bothersome This was said of many other opiates. Tramadol and Methadone were suppose to be non-addictive, too!

Matthew J. Smith

I see any new understanding about how to treat pain as a good thing, and am pleased that they might make opiates “better”, but I , too, worry about the costs of new patented medications, especially when it seems they are trying to close off access to inexpensive meds that do work for many of us. …. I have had severe, chronic, neuropathic pain for more than 8 years now, and am on antidepressants as well as opiates while having tried mind bending drugs like gabapetin and lyrica with no success in combating pain wth them , while at the same time having been shocked by their side effects …… When I look at the numbers of recreational users who do themselves harm with opiatez, I am appalled but their numbers need to be weighed against the enormous number of people who are allowed a better quality of life with responsible opiate use.


Maybe we should be looking to delta and not mu. Interesting!

Jasmin Days

Basically, patients will still be taking opiates. What a joke!!!!! Just leave people alone. People will do what they want to do!!!


Humans are not rats- not all anyway!

It seems to me you are creating new jobs for new scientists that are NOT studying the real pain diseases. We found what works for most of us. You want to call it bad names for something that has given us a chance to live without screaming in pain.. Suffering etc. You will be killing many people who has the right to have meds that help. These meds don’t make them high… They go right to the damaged area and does it’s job. you are playing around with it for I wonder to benefit yourself or other organizations that are not in the patients best interest. It’s just like the Bible says or even like a James Bond movie… GOOD against Evil. One day the truth will come out. I wonder if any of you will have a serious pain diseases or not allowed to be old with no help if needed????? Our young people can get these pain diseases too and do!!!! I don’t trust anyone who says a brain trigger etc. It takes away the truth from REALITY.! We have a disease and need help with our suffering and meds we are on WORK! ¡!


Ten, twenty years? Then how much until it’s affordable as a generic? Or maybe I’ll stop taking asthma medication so I can afford the only pain relief my doctor will prescribe.

Sorry, I’ve lost my sense of optimism. I’m broke because I’ve put a lot of money into trying to get help. Copays, deductibles, tests, doctors who didn’t tell me what they diagnosed me with, doctors who shoved anti-depressants at me so I would go away. I had sleep apnea and osteoarthritis. Yeah, now I sound depressed. I do. It’s the broken system, the doctors, the costs. I can’t afford the help I need, really. I’m choosing between this doctor and that treatment. I’m choosing between food or medicine sometimes. At age 37.

There is a point where anyone who isn’t depressed by our situation may be the outlier. I had a psychologist once tell me, “In your situation, it would be normal to be depressed.” Dysthmia, technically. An anti-depressant might make me feel better, but the broken system is still broken.

If politicians want to get involved in my medicine cabinet, then they ought to fix the system. No, they’d rather cater to Big Pharma and the insurance industry.

Had this research been funded years ago, maybe we’d have an alternative by now. We need the alternative yesterday. We face a lot of pressure and there aren’t alternatives.


I do hope this medication turns out to be all they say it will but I worry not only about the probable cost of a new drug but also side effects they won’t see until it’s been on the market for years and many people are hurt by it! Remember how many drugs are touted as non addictive and “safe” only to find out the realities of the “miracle” drug.