Marc RobitailleCan we fight pain with pain as you fight fire with fire? This seems possible, at least in part, judging by a study that two researchers from the Faculty of Medicine published this week in the journal Nature Neuroscience .
Indeed, Robert Bonin and Yves De Koninck has shown that it is possible to reduce the sensitivity to pain by a two-step approach which involves waking pain then prevent neurochemical reconsolidation. Both researchers at the Mental Health University Institute in Quebec were inspired by work on memory conducted there fifteen years to explore this avenue of treatment.
This work had shown that when a memory is activated, its neurochemical encoding is temporarily unlocked. The use of a product prevents neurochemical reconsolidation of memory has the effect of erasing the memory.
To determine whether a similar mechanism exists for pain, two researchers first injected capsaicin into the paw 24 laboratory mice. "It is the very molecule that causes burning chili says Yves De Koninck. It activates receptors intense heat, as if they came into contact with a hot object. Although capsaicin does not cause any physical damage, it triggers the mechanism of pain sensitivity. " Indeed, in the hours after the injection, the mice become hypersensitive. They tolerate the pressure on their leg is barely a third of what it was previously. This hypersensitivity depend synthesized proteins in the spinal cord.
Three hours after the injection, the mice were administered a second dose of capsaicin and a product that inhibits protein synthesis. Result: hypersensitivity quickly faded. In just two hours, the permissible pressure on the leg had risen to 70% of what it was originally.
Surprisingly, when the protein inhibitor is administered without injection of capsaicin, hypersensitivity remains. "The second injection of capsaicin seems necessary to make labile sensitivity to pain and to change its neurochemical consolidation," says Professor De Koninck.Additional tests conducted using an inflammatory product that simulates chronic pain yielded similar results. Hypersensitivity begins to decrease just three hours after the injection of capsaicin and inhibitor of protein while she held for eight days in mice that did not benefit from this intervention.
Highlighting this strange mechanism suggests a new way to relieve pain, especially chronic pain. "It takes advantage of the neurochemical reorganization of synapses that occurs when pain wakes to inject a protein inhibitor that erase hypersensitivity offers Yves De Koninck. The challenge now is to find a protein inhibitor that is non-toxic and causes few side effects in humans. "