Chronic pain could be treated with the compound that gives chillies their kick, according to scientists.
An Aberdeen University study identified how genes are “turned on” so that humans feel pain. Capsaicin, a compound in chillies, was also found to be capable of flicking the switch.
The study could lead to a new line of painkilling drugs being developed.
The team examined the pain gene known as substance-P - first associated with chronic inflammatory pain more than 30 years ago.
Genes need “switches”, known as promoters and enhancers, to turn them on in the right place, at the right time and at the right level.
One of the major findings of the study was that the switches do not act in isolation and need other switches to “speak to” in order to activate the gene.
Researchers based in the university’s Kosterlitz Centre for Therapeutics spent five years looking for the switches that turn the substance-P gene on in a group of cells called sensory neurones.
Dr Lynne Shanley said: “Finding the switch was like looking for a needle in a haystack.
“However, by comparing the genetic sequences of humans, mice and chickens, we were able to find a short stretch of DNA that had remained unchanged since before the age of dinosaurs.
“We were delighted when this little bit of DNA turned out to be a genetic switch, or enhancer sequence, which could turn on the substance-P gene in sensory neurones.”
Chronic inflammatory pain in the form of arthritis and other conditions affects thousands of people in the UK each year and in many cases is untreatable.
The findings are published in the journal Neurosignals.