Scientists say they may have found a gene that regulates chronic pain, a discovery that could help researchers develop more effective and targeted painkiller drugs.
The research so far has been performed only on mice. But for the thousands of Canadians suffering from chronic pain, any research that lays the groundwork for better medications is always welcome.
The gene they focused on is called HCN2 and is located at the pain-sensitive ends of nerves. Scientists have known about the gene's existence for some time, but its role in pain was unclear.
So a group from Cambridge University tried creating genetically modified mice in which the HCN2 gene had been deleted.
They measured how quickly the mice withdrew from different types of painful stimuli and discovered that deleting the HCN2 gene took away neuropathic pain, the kind of pain linked to nerve damage.
But deleting HCN2 appeared to have no effect on normal "acute pain" such as the type of pain caused by accidentally burning yourself. That was key, since pain acts as a useful warning signal to the body, says the study's lead author, Prof. Peter McNaughton, the head of the Department of Pharmacology at the University of Cambridge.
"Many genes play a critical role in pain sensation, but in most cases interfering with them simply abolishes all pain, or even all sensation. What is exciting about the work on the HCN2 gene is that removing it – or blocking it pharmacologically- eliminates neuropathic pain without affecting normal acute pain. This finding could be very valuable clinically because normal pain sensation is essential for avoiding accidental damage," he said in a university press release.
The results appear in the journal Science.
Neuropathic pain is caused by damaged nerve fibres that send incorrect signals to other pain centres. It is often the result of injury or amputation, but can also be an effect of shingles, diabetes or cancer treatment.
Neuropathic pain is also notoriously hard to control with medications. Opiates such as morphine are sometimes effective, but they are typically addictive and carry significant side effects.
