The laser torture of volunteers has helped biologists figure out how the body can be made to increase the number of opioid receptors in the brain, thereby raising the pain threshold and making a person less sensitive to chronic pain, according to an article published in the journal Pain.
“We do not yet know which mechanisms are responsible for this increased pain tolerance, but if we can uncover this secret and understand how they can be improved in more traditional ways. This will enable us to naturally increase pain tolerance while avoiding the unpleasant side effects of opiates,”said Christopher Brown of the University of Manchester, UK.
Brown and his colleagues discovered why some people tolerate chronic pain better than others, and found a way to "instill" this ability in humans by observing the brain work of a dozen volunteers suffering from arthritis who agreed to participate in an unusual experiment.
As part of these experiments, scientists sat their wards in a positron emission tomograph, asked them to drink a liquid with a special radioactive "sugar", and then subjected them to "stimulation" with a laser that burned their hand.
By observing the activity of the pain center in the brain, the scientists tried to objectively assess how much pain the volunteers experienced and how well they endured it. The biologists compared these indicators with how they tolerated pain and how the brain worked in healthy people from the control group, who were also "stimulated" by a laser.
Neuron coated with opioid receptors
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Photo: University of Manchester
These laser tortures showed that a person's ability to tolerate pain depended on how many so-called opioid receptors were contained in nerve cells in the part of the brain that controls pain.
As a rule, the more such receptors were on the surface of the pain center cells, the less the participants in the experiments reacted to the laser burning.
“People are usually very gloomy and fatalistic about chronic pain. Our research has shown that the pain management system is very flexible in nature and that humans can make it adapt to persistent pain. Perhaps we can find some simple ways to speed up and improve this adaptation process and create drugs that do it,”concludes Anthony Jones of the Manchester Pain Consortium.
