However, they say there may be a way to switch off this pain-amplifying mechanism.
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A new study from the University of Colorado Boulder suggests that prescription painkillers such as morphine might be causing an increase in chronic pain instead of treating it.
Although the opioid-based painkillers’ effects are not tested on humans, further study is required to know if these drugs could have the same effect on humans as it did on the rats in the study. This means that although treating someone with morphine after an initial injury may help lessen their pain, doctors should consider limiting morphine use to a short time to avoid an increase in pain and chronic pain. The signal, in outcome, increased the excitability of pain-responsive nerve-cells in the brain and spinal cord.
Increasing use and abuse of opioids, however, has become a major public health concern in the USA; opioid overdoses are responsible for 78 deaths in the country every day.
The results suggest that the recent escalation of opioid prescriptions in humans may be a contributor to chronic pain, Grace said.
A potentially groundbreaking new study finds that using opiod-based painkillers does something completely unexpected to rats. Not only that, the rats treated with morphine experienced chronic pain even months after the treatment, while the untreated rats experienced less long-term pain.
Scientists have known for more than three decades that nerve injuries intensify the release of pain signals. One group was given nothing while the other got morphine for five days. Mice suffering from chronic pain were given morphine for five days. This as a result causes prolong pain that lasts several months. “We found the treatment was contributing to the problem”, CU-Boulder Assistant Research Professor Peter Grace said.
The researchers found that when a peripheral injury is combined with morphine treatment, both of them cause a glial cell signaling cascade, which produces a cell signal from a protein called interleukin-1beta (IL-1b) that elevates activity of pain-responsive nerve cells in the spinal cord and brain. This process can increase and prolong pain.
The study was funded in part by the American Pain Society, Australia’s National Health and Medical Research Council, the National Natural Science Foundation in China, the National Institute on Drug Abuse, the National Institute of Dental and Craniofacial Research and the National Institute of Alcohol Abuse and Alcoholism.
It is not all bad news, however. Besides various medications, some patients may find relief from chronic pain through surgery, nerve blocks or electrical stimulation, alternative therapies like acupuncture, or self-management to cope with their daily tasks despite the pain.
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He adds that drugs that can block such receptors are now in development, but it is likely to be at least another 5 years before they are available for clinical use.
