‘Off Switch’ For Pain Discovered: Activating The Adenosine A3 Receptor Subtype Is Key To Powerful Pain Relief

In research published in the medical journal Brain, Saint Louis University researcher Daniela Salvemini, Ph.D. and colleagues within SLU, the National Institutes of Health (NIH) and other academic institutions have discovered a way to block a pain pathway in animal models of chronic neuropathic pain including pain caused by chemotherapeutic agents and bone cancer pain suggesting a promising new approach to pain relief.

The scientific efforts led by Salvemini, who is professor of pharmacological and physiological sciences at SLU, demonstrated that turning on a receptor in the brain and spinal cord counteracts chronic nerve pain in male and female rodents. 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).

An Unmet Medical Need

Pain 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.

For the past decade, scientists have tried to take advantage of these known pathways -- the series of interactions between molecular-level components that lead to pain. While adenosine had shown potential for pain-killing in humans, researchers had not yet successfully leveraged this particular pain pathway because the targeted receptors engaged many side effects

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