It's opened the door to developing a drug to treat the condition for which existing painkillers do little.

Diabetes, chemotherapy drugs, multiple sclerosis, injuries and amputations have all been associated with neuropathic pain, usually caused by damage to nerves in various body tissues, including the skin, muscles and joints. Mechanical hypersensitivity – or mechanical allodynia – is a major symptom of neuropathic pain, where innocuous stimuli like light touch cause severe pain.

Many available pain medications aren't effective in reducing this often-debilitating type of chronic pain. However, researchers at the University of Texas at Austin (UT Austin), in collaboration with UT Dallas and the University of Miami, may have advanced the treatment of neuropathic pain by discovering a molecule that reduces mechanical hypersensitivity in mice.

"We found it to be an effective painkiller, and the effects were rather long-lived," said Stephen Martin, a co-corresponding author of the study. "When we tested it on different models, diabetic neuropathy and chemotherapy-induced neuropathy, for example, we found this compound has an incredible beneficial effect."

The compound is FEM-1689, which binds to the sigma 2 receptor (σ2R), which was identified in 2017 as transmembrane protein 97 (TMEM97). The researchers had previously found that several small molecules that bind selectively to σ2R/TMEM97 produce strong and long-lasting anti-neuropathic pain effects in mice. FEM-1689, one such small molecule, was found to have improved selectivity for σ2R/TMEM97.