"Nearly everyone will experience persistent pain at some point in their lifetime," said Dr Kenneth Hargreaves, a professor of Endodontics at the University of Texas.

"Our findings are truly exciting because they will offer physicians, dentists and patients more options in prescription pain medications."

"In addition, they may help circumvent the problem of addiction and dependency to pain medications, and will have the potential to benefit millions of people who suffer from chronic pain every day."

"Capsaicin is an ingredient in hot chilli peppers and causes pain by activating a receptor called transient potential vanilloid 1 (TRPV1)."

"We started out seeking the answer to the question: 'Why is TRPV1 consistently activated in the body upon injury or painful heat?'"

"We wanted to know how skin cells talk to pain neurones."

"What we found was much more surprising and exciting."

"We have discovered a family of endogenous capsaicin-like molecules that are naturally released during injury, and now we understand how to block these mechanisms with a new class of non-addictive therapies."

Experiments on mice showed that they creates their own natural endogenous capsaicins when they were subjected to pain.

These compounds were later identified as a series of fatty acids called oxidized linoleic acid metabolites (OLAMs) -- metabolises from the linoleic acid that is found naturally in the body.

Dr Hargreaves and his colleages have now developed two new classes of painkillers using drugs that either block the synthesis of OLAMs or antibodies that inactivate them.

With the right drug delivery technology, these new painkillers have the potential to deal with pain at its source -- in contrast to opiates that must travel to the brain to be effective.

Crucially, these novel analgesics have none of the addictive potential of opiates.

"This is a major breakthrough in understanding the mechanisms of pain and how to more effectively treat it," Dr Hargreaves said.

"These data demonstrate, for the first time, that OLAMs constitute a new family of naturally occurring capsaicin-like agents, and may explain the role of these substances in many pain conditions."

"This hypothesis suggests that agents blocking either the production or action of these substances could lead to new therapies and pharmacological interventions for various inflammatory diseases and pain disorders such as arthritis, fibromyalgia and others, including pain associated with cancer."