Researchers at Stanford Medicine have identified a potential new opioid-free method of treating pain and it was inspired by chickens!
They were able to lessen the sensitivity to pain in mice without affecting the receptor’s other features, like sensitivity to heat, by selectively targeting a particular region of a well-known pain receptor.
Farmers know all too well that mammals such as mice and squirrels will not eat chicken feed laced with Capsaicin – the compound that causes chili peppers to be spicy.
Sure enough, Capsaicin causes a burning sensation in mammals by turning on a pain receptor but it does not have much of an effect on most bird species.
Eric Gross, MD, Ph.D. explains that “birds are naturally resistant to capsaicin.”
That knowledge led Gross to ask himself whether some people could also have a genetic variant that makes the same receptor more similar to the one of birds, making them more resilient to pain as a result.
Gross and his team then published a study in the Journal of Clinical Investigation, in which they identified a really rare genetic variant that does indeed reduce pain sensitivity in humans.
More importantly, as rare as the gene may be, its mere existence prompted the scientists to replicate the same effects using a custom designed medication.
The study’s senior author says that “We were amazed there was such a decrease in activity of TRPV1’s response when we made this genetic variant. We actually tried it several times just to make sure that was truly what we were seeing.”
Gross estimates that pain was reduced by about 50 percent, which is actually ideal since this nervous response, while unpleasant, plays an important role in protecting us all from danger.
“You do not want to take away the full sensation of pain. You still want to have someone, if they place a hand over a hot stove or if they step on a Lego, to have that pain sensation.”
In other words, the lab mice were able to enjoy a pretty fortunate medium by experiencing less pain while still sensing all harmful stimuli.
“We were able to just dial it down rather than take it away completely,” he says.
This new chicken-inspired drug works more selectively and with fewer side effects when compared to earlier attempts to treat pain by targeting TRPV1.
Gross explained that “Instead of directly activating or inactivating the receptor, the drug we developed modulates only a specific area of the receptor. We’re able to avoid the side effects that have been plaguing drug discovery for TRPV1 for quite some time.”
When used in pain relief creams or patches, a high concentration of Capsaicin desensitizes the receptor, but it also causes pain to worsen first before getting better.
Drugs that block the receptor, on the other hand, have failed in clinical trials because they made people overheat.
Gross’s team wishes to change the peptide to make it more effective at reducing pain for a longer period of time.