The numbers of
opiate receptors in the brain increases to combat severe pain
(October 23, 2015) Scientists
at The University of Manchester have shown for the first time that the numbers
of opiate receptors in the brain increases to combat severe pain in arthritis
sufferers.
Chronic pain – pain which lasts for more than six months –
is a real problem for many people with approximately 46% of the UK population
estimated to suffer from it (comprising 20% of consultations in general
practice). However, some people seem to
cope better than others with pain, and knowing more about how these coping
mechanisms work might help to develop new ways of treating this distressing
symptom.
It has been known for a long time that we have receptors in
our brains that respond to natural painkilling opiates such as endorphins, but
the researchers in Manchester have now shown that these receptors increase in
number to help cope with long-term, severe pain.
By applying heat to the skin using a laser stimulator, Dr
Christopher Brown and his colleagues showed that the more opiate receptors
there are in the brain, the higher the ability to withstand the pain.
The study used Positron Emission Tomography (PET) imaging on
17 patients with arthritis and nine healthy controls to show the spread of the
opioid receptors.
This suggests that the increase in opiate receptors in the
brain is an adaptive response to chronic pain, allowing people to deal with it
more easily.
Dr Brown said: “As far as we are aware, this is the first
time that these changes have been associated with increased resilience to pain
and shown to be adaptive.
“Although the mechanisms of these adaptive changes are
unknown, if we can understand how we can enhance them, we may find ways of naturally
increasing resilience to pain without the side effects associated with many
pain killing drugs.”