Brain chemical that can help reverse chronic pain

A chemical in the brain typically associated with cognition, as well as regulating movement and emotion, among others, may help reverse chronic pain, new research has found. The brain chemical dopamine plays a role in promoting chronic pain, the findings showed.

"These findings demonstrate a novel role for how dopamine contributes to maintaining chronic pain states," said Ted Price, associate professor at the University of Texas at Dallas. "This may open up new opportunities to target medicines that could reverse chronic pain," Price noted.

The researchers followed the sequence of pain impulses travelling from the brain to the spinal cord in mice. They found that by removing a collection of neurons called A11 that contain dopamine, chronic pain was selectively diminished.

Pain signals travel like electricity from an injury to the spinal cord where they pass on electrical or chemical pain signals to other cells. Those pain signals then travel upward and relay that information to neurons in the brain where they can be distributed throughout. There is no single pain centre in the brain, but there is substantial evidence that chronic pain changes how these pain centres are activated.

In people with chronic pain, neurons continue to send pain signals to the brain, even in the absence of injury, but the causes of this are not known. A potential explanation comes from A11. These neurons did not affect acute pain, but they did have a profound effect on chronic pain, the researchers found. By targeting these neurons in mice with chronic pain, the researchers permanently reversed a chronic pain state.

(The study appeared in The Journal of Neuroscience)