Narcotic painkiller addiction kills thousands of people each year because of fatal drug overdoses and opioid addiction. Now, a new research led by researchers at the University of Colorado Boulder suggests that opioids could actually have far-reaching implications in humans that previously expected.
During the study, the researchers discovered that rats who were subjected to morphine treatment experienced a paradox and a peculiar effect - they experienced more pain. This particular behavior can have a lot of long-term implications in humans, EurekAlert has learned.
According to the team, a few days of morphine treatment resulted in chronic pain in mice that continued for months, even after when the treatment was stopped. The chronic pain continued for months because of the release of a specific pain signals from immune cells that reside in the spinal cord. Professor Peter Grace, the lead study researcher believes that the findings indicate that the increase in opioid prescription among people could be a potential contributor to chronic pain.
"What we found is that the opioid painkiller activates spinal immune cells, causing a further inflammatory response. The pain is effectively transitioned to a chronic state, making the pain itself both more severe and longer lasting," Grace said, in an interview with HealthCanal. "This extended period of chronic pain has followed from just five days of treatment with morphine, which in itself is very significant."
The research team used the Designer Receptor Exclusively Activated by Designer Drugs (DREADD) technology to isolate immune cells from the spinal cord of the mice. The immune cells were then used to see how they respond to opioid use.
Grace further explained how the team were successful in blocking the two main receptors that were involved in the immune response - TLR4 and P2X7R. Both these receptors have previously been associated with chronic pain.
Blocking these two receptors helped researchers stop the immune response from taking place in the body of the rats. This way, the morphine just produced the painkilling benefits, and there was no indication of any further chronic pain.
The researchers believe that the implications of the study in humans taking oxycodone, morphine and methadone are huge. A short-term decision to take these drugs can actually produce long-term effects that can make the pain worse.
The following video talks about America's epidemic of opioid abuse: