Even cooler: it’s found naturally in the body.
Morphine and other opiate-based pain medicines are the go-to treatments for severe or chronic pain, but it’s widely known that these drugs are highly addictive. Even when used properly in a medical setting, patients can build up a tolerance to and dependence on the drugs, so scientists have been working feverishly to find a painkiller without this nasty side effect — they’ve even experimented with using centipede venom as a painkiller in place of morphine.
Now in a new study, researchers engineered variants of the neurochemical endomorphin, which is found naturally in the body, and compared its effectiveness and side effects to morphine. The drug is peptide-based and targets the same pain-relieving opioid receptor as morphine.
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"These side effects were absent or reduced with the new drug," said lead investigator James Zadina, professor of medicine, pharmacology and neuroscience at the Tulane University School of Medicine. "It's unprecedented for a peptide to deliver such powerful pain relief with so few side effects."
According to the National Institute on Drug Abuse, it’s estimated that between 26.4 million and 36 million people around the world abuse opioids. In 2010, over 16,1600 opioid-related deaths occurred in the US alone, and the trends show that the problem is on an alarming rise.
The new endomorphin drug even managed to produce longer pain relief in rats, and it achieved this effect without substantially slowing down breathing. When researchers administered a similarly potent dose of morphine, they observed significant respiratory depression. The rats also experienced impairment of motor skills and coordination after taking morphine, but this effect did not appear with the endomorphin drug.
The scientists also performed several experiments to see if the drug would be addictive. For instance, one test revealed that rats would spend more time in a compartment where they had received morphine, but the new drug did not have the same behavioral affect. In another test where the rats could press a bar to produce an infusion of the drug, the scientists noted that rats only increased their efforts to obtain morphine, but not the new endomorphin drug.
Another pro is that the new drug didn’t produce the same effects on tolerance as morphine, and didn’t produce spinal glial cell activation, which is an inflammatory effect of morphine that’s known to contribute to tolerance.
The results certainly seem promising, and the researchers hope to begin human clinical trials within the next two years. We could be in for some exciting advancements in the pain-related field of medical science.
Their research is published in the journal Neuropharmacology.