A woman who spent her whole life unable to feel pain has been hurt for the first time after researchers gave her a drug used to treat heroin overdoses – and they think this could lead to a breakthrough in pain relief.
Scientists studied the woman to try and figure out exactly what causes pain – and how it can be stopped.
Her rare condition meant she couldn’t tell if she ran her fingers under scalding or freezing water, but after scientists gave her a medicine to block opioids she was able to feel pain when burned her with a hot laser.
Researchers wanted to find treatment for pain which didn’t have the side effects related to morphine which include addiction and a loss of effectiveness over time.
Thanks to this breakthrough, new drugs could be available in just a few years.
University College London researchers studied people who don’t feel pain because of a genetic mutation, and found out they naturally produce more opiates in their body.
But if they gave them naloxone, a drug which blocks the effects of opiates, they felt pain for the first time in their lives.
Scientists now think they can replicate the painlessness some people feel naturally using a drug.
When something is painful, electrical signals are passed along nerve cells using ‘channels’, proteins that conduct the electrical impulse. One of the most important channels for signalling pain is Nav1.7 (catchy name) which transports sodium.
People who don’t feel pain were born without this, and so in the past scientists tried to mimic this by blocking the Nav1.7 in normal people – but it didn’t really work.
It turns out people born without pain also produce higher than normal levels of opioid peptides (feelgood chemicals we create, for example endorphins).
This is the breakthrough from their study, published in Nature Communications, which could allow for a new combo drug to be created. They will block the chemical that channels the pain signals while also giving a low dose of opiod peptides (a much lower dose than if someone was given, say, morphine).
The results are encouraging because people who naturally feel no pain produce small amounts of opioids all their lives, but don’t develop a tolerance or experience side effects.
People are already given broad-spectrum sodium channel blockers as local anaesthetics, but they are not suitable in the long term because they cause total numbness.
But people born without Nav.1.7 still feel touch normally, and the only side effect is they cannot smell.