Most of the pain receptors in our bodies are only able to detect one particular type of pain, according to a new study in the journal Science Advances. This new discovery could have major repercussions for the treatment of various injuries and other uncomfortable conditions, by allowing researchers and doctors to target the specific groups of neurons responsible for producing certain sensations.
Known as nociceptors, the body’s pain receptors are nerve endings that detect harmful external stimuli, generating impulses that are then transmitted to the brain. Until now, it had been largely assumed that most nociceptors were sensitive to all types of pain, although this latest research indicates that more than 85 percent are in fact responsive to only one kind of injury.
The study authors used mice that had been genetically engineered so that their pain-sensitive neurons became illuminated with fluorescent proteins whenever they were activated. These mice were then subjected to either a small pinch, cold water, or hot water in order to stimulate the nociceptors in one of their paws, while the researchers observed which neurons were lit up by each event.
Only around 5 percent of neurons responded to all three types of pain, while roughly 10 percent responded to two of the three stimuli. The vast majority, however, were found to be sensitive to either mechanical, cold, or heat injuries, and completely unresponsive to the other two kinds of pain.
“This technology should allow us to identify sets of sensory neurons that are activated in different pain states,” write the study authors. This, they say, could help them to “define subsets of neurons that may be associated with distinct pain conditions,” thereby opening the door to new, highly specialized treatments that target only the relevant neurons.