Drugs that target a specific melatonin receptor appear to relieve chronic pain that results from nerve damage.
This condition, known as neuropathic pain, is often severe and can be permanent. It develops after nerve damage from conditions such as shingles, injury, amputation, autoimmune inflammation, and cancer.
Melatonin, a neurohormone present in mammals, acts on the brain by activating two receptors called MT1 and MT2. Those receptors are responsible for regulating several functions, including sleep, depression, anxiety, and circadian rhythms.
A team led by Gabriella Gobbi, associate professor of psychiatry at McGill University, demonstrated that a drug called UCM924, which targets the MT2 receptors, relieves chronic pain in animal models. The team also identified the drug’s mechanism in the brain.
The drug is able to switch off the neurons that trigger pain and switch on the ones that turn off pain by activating the MT2 receptors in the periaqueductal grey (a brain area controlling pain). The findings are reported in the February issue of the journal PAIN.