Brain Region Key to Chronic Pain Identified, Offering Potential for New Therapies
Researchers have pinpointed a specific area within the brain – the parabrachial nucleus - that plays a crucial role in the development of chronic pain, potentially opening avenues for novel treatment strategies. The study, published in Nature on October 8th, reveals a subset of neurons within this region that remain active long after an initial injury, contributing to persistent pain.
The research, conducted on mice, suggests that this prolonged neural activity isn’t simply a continuation of the initial pain signal, but a distinct state linked to the experience of chronic pain, which affects approximately one in five people worldwide. “Pain is in your head. But it is indeed very real,” explains Nicholas Betley, a biologist at the University of Pennsylvania in Philadelphia and a co-author of the study.
The team discovered that these neurons, carrying receptors for a signalling molecule called neuropeptide Y, switch on following a painful stimulus like nerve damage and continue firing even after the initial injury has healed.Artificially activating these ‘Y1R’ neurons in mice induced pain-associated behaviors, while blocking their activity reduced persistent pain without impacting normal, short-lived pain responses to immediate threats like heat.
“The Y1R neurons alone don’t cause the feeling of pain,” Betley clarifies, “But, they form part of the network ‘that leads to the sensation that we refer to as pain’.”
Interestingly, the study also revealed the brainS own potential pain-killing mechanism.When mice experiencing chronic pain were subjected to stressors like food or water deprivation, or exposure to a frightening stimulus (such as bobcat urine), their persistent pain decreased. This reduction correlated with an influx of neuropeptide Y into the parabrachial nucleus, released by neurons activated by these urgent needs.
Co-author Ann Kennedy, a neuroscientist at the Scripps Research Institute in La Jolla, California, explains this finding: “We think of pain as just a sensory input … but the sensation of pain is a lot more malleable, and it’s changed by our experiences.” The researchers hypothesize that when faced with more pressing needs, the brain prioritizes those over pain, effectively dampening the activity of the persistent-pain neurons.
If these findings are confirmed in humans, they could lead to the development of new therapies targeting the parabrachial nucleus and neuropeptide Y signaling to alleviate chronic pain.
