Medical researchers say they have discovered an ‘off switch’ for pain.

Specifically, a group of academics say they have found a way to block a pain pathway in animal models of chronic neuropathic pain including pain caused by chemotherapeutic agents and bone cancer pain.

The find could lead to a promising new approach to pain relief.

A joint project between Saint Louis University and the National Institutes of Health (NIH) in the US has demonstrated that turning on a receptor in the brain and spinal cord counteracts chronic nerve pain in male and female rodents.

It appears that activating the A3 receptor – either by its native chemical stimulator, the small molecule adenosine, or by powerful synthetic small molecule drugs invented at the NIH – prevents or reverses pain that develops slowly from nerve damage without causing analgesic tolerance or intrinsic reward (unlike opioids).

The treatment of pain itself is an enormous problem.

As an unmet medical need, pain causes suffering and comes with a multi-billion dollar societal cost.

Current treatments are problematic because they cause intolerable side effects, diminish quality of life and do not sufficiently quell pain.

The most successful pharmacological approaches for the treatment of chronic pain rely on certain “pathways”; circuits involving opioid, adrenergic, and calcium channels.

But scientists are now trying to take advantage of these known pathways – the series of interactions between molecular-level components that lead to pain – to find better way to bring relief without the many side-effects.

Researcher Daniela Salvemini says activation of the A3 adenosine receptor subtype is central to mediating the pain-relieving effects of adenosine.

It has long been appreciated that harnessing the potent pain-killing effects of adenosine could provide a breakthrough step towards an effective treatment for chronic pain,” Salvemini said.

“Our findings suggest that this goal may be achieved by focusing future work on the A3AR pathway, in particular, as its activation provides robust pain reduction across several types of pain.

“These studies suggest that A3AR activation by highly selective small molecular weight A3AR agonists such as MRS5698 activates a pain-reducing pathway supporting the idea that we could develop A3AR agonists as possible new therapeutics to treat chronic pain.”

The latest research paper has been published in the medical journal Brain