Natural Opioids Linked to Chronic Pain

     

        This article discusses how the body's way of numbing acute pain through naturally released opioids can actually result in a reemergence of the pain even after a couple of months. Bradley Taylor, a neurobiologist from The University of Kentucky Medical Center, studied this process in mice and discovered how inhibiting an already activated MOR or mu opioid receptor could cause a relapse in pain.
       The mice were injected in their paws with complete Freund's adjuvant(CFA) which simulates pain caused by inflammation. After the opioids helped to numb the pain in the mice, the researchers meddled with the signaling pathway that released the opioids. The pain once again reemerged in the mice that were initially injected with the CFA. The researchers then were able to note that this reemergence was due to the inhibition of the MOR. When the body gets injured and the opioids are released, the pain eventually subsides but the MOR pathway that releases the opioids is still left on. Essentially opioids bind to the mu opioid receptor, thereby activating the receptor in such a way that even when the opioids are gone, the receptor still inhibits the pain signal that is sent to the brain. This causes the mice to eventually not feel the pain. When the researchers interfered with this process, they stopped the MOR from preventing the pain signal from reaching the brain. This caused the mice to  feel the pain that was initially numbed down by the opioids. The mice also demonstrated signs of withdrawal through jumping and experiencing tremors in their paws leading the researchers to further deduce that the reemergence of the pain could be linked to opioid withdrawal. This was confirmed when adenylyl cyclase type 1 was discovered as it is known to have a correlation with drug addiction.
      I feel that this article is both interesting and important as understanding how our body deals with pain helps us to develop better analgesics. Understanding the advantages and the flaws of our body's response to pain can help scientists create painkillers that don't have the problems that our body has with natural painkillers such as opioids. As there is also a link to drug addiction in this area of research, one can also better understand addiction and develop treatments that help victims overcome their situation and lead a better life. Scientists may even be able to find connections between this process and the way that other neurological responses occur.




Link: http://www.the-scientist.com/?articles.view/articleNo/37538/title/Natural-Opioids-Linked-to-Chronic-Pain/