Pain serves as a valuable warning signal, but when it becomes chronic, pain should be considered as a real disease. An international team including research scientists from the CNRS and INSERM1 has identified and controlled one of the centres associated with chronic pain. This work, published in December 2016 in Molecular Psychiatry, made it possible to relieve the symptoms in mice and demonstrated the ability of the brain to remedy this problem.
In order to study these receptors, scientists generally use a ligand that can activate or inhibit them. The team innovated by creating a specific, photo-controlled ligand, optogluram, whose action on mGlu4 is directed by light. The use of optical fibers then enabled them to achieve very precise control of the activation of this neuroreceptor in a particular region of the brain. The scientists worked on mice that were conscious and free to move around, but suffering from chronic inflammatory pain. By activating optogluram with light, they were able to rapidly and reversibly inhibit their painful symptoms, thus demonstrating that the brains of these mice preserved their ability to counteract these effects. By identifying a modulator that can act on chronic pain, this work raises hopes for the development of new therapies.