|Researchers discover recipe for painlessness|
|Using transgenic mice, researchers have discovered how to replicate the painlessness experienced by people with rare mutations, which might lead to the development of next-generation painkillers, according to a study released Friday by the University College London (UCL).
People born with a rare genetic mutation are unable to feel pain. This is connected to certain mechanism in the nervous system. There are "channels" that allow messages to pass along nerve cell membranes, and they are vital for electrical signaling in the nervous system.
Previous study has shown that sodium channel Nav1.7 is particularly important for signaling in pain pathways and people born with non-functioning Nav1.7 do not feel pain. Drugs that block Nav1.7 have since been developed but they had disappointingly weak effects.
The new study, published in the journal Nature Communications, reveals that mice and people who lack Nav1.7 also produce higher than normal levels of natural opioid peptides.
To examine if opioids were important for painlessness, the researchers gave naloxone, an opioid blocker, to mice lacking Nav1.7 and found that they became able to feel pain. They then gave naloxone to a 39-year-old woman with the rare mutation and she felt pain for the first time in her life.
"The secret ingredient turned out to be good old-fashioned opioid peptides, and we have now filed a patent for combining low dose opioids with Nav1.7 blockers. This should replicate the painlessness experienced by people with rare mutations, and we have already successfully tested this approach in unmodified mice," said Professor John Wood, one of the authors of the research paper.
People with non-functioning Nav1.7 produce low levels of opioids throughout their lives without developing tolerance or experiencing unpleasant side-effects, according to Professor Wood.
"We hope to see our approach tested in human trials by 2017 and we can then start looking into drug combinations to help the millions of chronic pain patients around the world," said Professor Wood.