Targeting the A3 Adenosine Receptor Activates “Off Signals” for Pain

New research undertaken at Saint Louis University, in concert with researchers from the National Institutes of Health, the University of Arizona, and 2 institutes in Quebec, reports the discovery of drugs targeting the A3 adenosine receptor (A3AR) that can “turn off” pain signals in the spinal cord to provide relief from chronic pain. The findings were published in the April issue of the Journal of Neuroscience. The study supports earlier demonstrations that 2 drugs that target the A3AR—IB-MECA and MRS5698—were effective in treating several models of chronic pain, including painful chemotherapy-induced neuropathy, metastatic cancer pain, and nerve injury.

In this study, researchers confirmed that A3AR drugs not only relieved pain, but did so by activating an inhibitory transmitter system known as the gamma amino-butyric acid (GABA) system. In areas of the spinal cord and brain dedicated to pain processing, A3AR activation promoted GABA signaling by preventing the breakdown and removal of GABA from neuronal synapses. A3AR drugs demonstrate good safety profiles in clinical trials as anti-inflammatory and anti-cancer agents, and the research team is enthusiastic about the potential of these new drugs to treat chronic pain in patients.

Read a news story about the study finding here.

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