Scientists find brain’s ‘brake’ that can switch off chronic pain

Researchers at Washington University School of Medicine in St. Louis found in mice that nerve damage can turn the locus coeruleus, a small brain region involved in pain regulation, from a pain-relieving system into a driver of chronic pain.

The team focused on mu opioid receptors, which are found on nerve cells in the locus coeruleus. These receptors respond to the body's natural opioids as well as opioid drugs and normally help reduce pain.

When researchers removed the receptors from the locus coeruleus in mice with nerve injuries, the animals became more sensitive to touch and heat. Restoring the receptors reversed this heightened sensitivity, effectively reducing the pain caused by the nerve injury.

The researchers also found that the receptors have different effects depending on the nerve pathways involved. This suggests that the locus coeruleus has several roles in controlling pain rather than acting as a simple on-off switch.

The findings may help explain why chronic nerve pain can persist even though the brain has its own pain-relief system. The study suggests that nerve injury may disrupt the opioid receptors that normally keep the locus coeruleus under control, allowing it to become a source of ongoing pain.

The researchers say the results could eventually lead to treatments that target opioid receptors specifically in the locus coeruleus instead of affecting receptors throughout the brain and body. Such an approach could potentially provide pain relief while reducing some of the problems associated with traditional opioid medications.

Earlier, Qazinform News Agency reported that researchers identified a potential new way to improve treatment for deadly brain tumors.